JP2002214070A - Instrument and method for eccentricity measurement and projection lens incorporating optical element measured for eccentricity by using them - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the slippage of the emitting direction of measuring light or the optical axis of a focusing lens system from affecting on measured results even when the slippage occurs due to the unstable attitude of a light source. SOLUTION: After the measuring light emitted from the light source 11 is split into first and second light rays, only the first light ray is condensed to a prescribed incident optical axis of an object 91 to be inspected and the first light ray reflected by the surface to be inspected of the object 91 and the second light ray which does not reach the object 91 are respectively caused to form light spots by introducing the light rays to the same measuring surface. The slippage of the centroidal position of the total light quantity of both light spots from a reference position is detected by means of an optical position detecting element 70 and the eccentricity of the object 91 is calculated based on the detected slippage. At the time of splitting the measuring light, the light quantities of the first and second light rays are adjusted to become almost equal to each other. In addition, the light rays are introduced to the measuring surface, so that the first light ray may slip by the same amount as that of the measuring light which slips in the emitting direction in the same emitting direction, and the second light ray may slip by the same amount in the direction opposite to the slipping direction of the first light ray.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an eccentricity measuring device for determining the eccentricity of a test object such as a lens, an eccentricity measuring method, and a projection lens incorporating an optical element whose eccentricity is measured by using these devices. About.

[0002]

2. Description of the Related Art In a conventional eccentricity measuring apparatus, a measuring light emitted from a light source is adjusted by a focus lens system and condensed on an optical axis of a test object (for example, a lens). The light reflected or transmitted through the test object is guided on the measurement surface to form a light spot. Then, the position of this light spot is detected by a light position detecting element (PSD) or the like, and the amount of deviation from a reference position (the position of the light spot formed on the measurement surface by the measurement light when there is no eccentricity) is obtained. Thus, the eccentricity of the test object is determined.

[0003]

However, in such an eccentricity measuring device, the emission direction of the measuring light may be shifted due to the unstable posture of the light source. When such a deviation in the emission direction of the measurement light occurs, the deviation appears as a deviation from the reference position of the light spot formed on the measurement surface, and an error may occur in the eccentricity measurement of the test object. .

Further, when an optical axis shift occurs in the focus lens system for condensing the measurement light on the optical axis of the test object, the optical axis shift also appears as a shift from the reference position of the light spot. Therefore, at the time of eccentricity measurement, the test object is rotated around the optical axis, and depending on whether or not the light spot on the measurement surface moves with this rotation, the deviation of the light spot from the reference position causes the deviation of the test object. It is necessary to judge whether it is due to the core or the optical axis shift due to the focus lens system, and there is a problem that the measurement operation takes time. Furthermore, when the assembling accuracy of the turntable for rotating the test object around the optical axis is insufficient and the test object cannot be rotated around the optical axis with high accuracy, the light spot on the measurement surface is , And a measurement error may occur.

The present invention has been made in view of these problems, and is directed to a case where the attitude of the light source is unstable and the emission direction of the measurement light is shifted, or the optical axis of the focus lens system is shifted. The eccentricity measuring device, eccentricity measuring method and eccentricity measuring method capable of performing highly accurate eccentricity measurement without affecting the measurement result, and a projection lens incorporating an optical element whose eccentricity is measured using these. It is intended to provide.

[0006]

In order to achieve such an object, a first eccentricity measuring apparatus according to the present invention comprises a light source,
After splitting the measurement light emitted from the light source into a first light and a second light having substantially equal light amounts, only the first light of these two lights is condensed on a predetermined incident optical axis of the test object, and The first light reflected from or transmitted through the test object at the test surface of the test object and the second light (not reaching the test object) are compared with each other with respect to the shift of the measurement light emission direction. The second light is guided on the same measurement surface in such a state that the same amount of displacement occurs in the same direction as the emission direction and the second light is displaced in the opposite direction to the first light. An optical system for forming a light spot,
A light position detecting means for detecting the position of the center of gravity of the total light amount of both light spots formed on the measurement surface; and an eccentricity of the test object based on the position of the center of gravity of the total light amount of both light spots detected by the light position detecting means. Eccentricity calculating means for calculating.

Further, in the eccentricity measuring method according to the first aspect of the present invention, the measuring light emitted from the light source is converted into a first light having substantially the same light amount.
After splitting into the light and the second light, only the first light of these two lights is condensed on a predetermined incident optical axis of the test object, and is reflected on the test surface of the test object or transmitted through the test object. The first light and the second light (which have not reached the object) are displaced by the same amount in the same direction as the displacement of the measurement light with respect to the displacement of the measurement light. , The second light is guided on the same measurement surface in such a manner that the same amount of displacement occurs in the opposite direction to the first light to form light spots of both lights, and the total light quantity centroid position of both light spots The eccentricity of the test object is calculated based on.

In the eccentricity measuring device and the eccentricity measuring method according to the first aspect of the present invention, the measuring light emitted from the light source is transmitted to the first eccentricity measuring device.
After splitting into the light and the second light, only the first light of these two lights is focused on a predetermined incident optical axis of the test object, and is reflected on the test surface of the test object or transmitted through the test object. The first light and the second light that have not reached the test object are guided on the same measurement surface to form respective light spots of the two lights. Calculate the eccentricity. Here, the first light and the second light are adjusted so that the light amounts of both light beams are substantially equal at the time of division, and the first light is emitted in the emission direction of the measurement light with respect to the shift in the emission direction of the measurement light. Since the same amount of displacement occurs in the same direction as the displacement, and the second light is guided on the measurement surface in such a manner as to produce the same amount of displacement in the direction opposite to the first light. The eccentricity of the test object obtained based on the position of the center of gravity of the total light quantity of both light spots is a value in which the angle shift between the two light beams caused by the shift in the emission direction of the measurement light is offset. For this reason, even when the orientation of the light source is unstable and the emission direction of the measurement light shifts, this does not affect the measurement result, and the eccentricity measurement of the test object can be performed with high accuracy. Become.

An eccentricity measuring apparatus according to a second aspect of the present invention divides a light source and a measuring light emitted from the light source into a first light and a second light, and divides both of the lights into the emission direction shift amounts of the measuring light. After the light is guided so as to produce the same amount of angular displacement with respect to
Only the light is condensed on a predetermined incident optical axis of the test object, and the first light reflected on the test surface of the test object or transmitted through the test object is guided onto the first measurement surface to form a first light spot. And an optical system that guides the second light (not reaching the test object) onto the second measurement surface to form a second light spot, and the first light beam formed on the first measurement surface. First light position detecting means for detecting the light quantity centroid position of the light spot; second light position detecting means for detecting the light quantity centroid position of the second light spot formed on the second measurement surface; The eccentricity of the test object is calculated based on the light quantity centroid position of the first light spot detected by the light position detection means and the light quantity gravity center position of the second light spot detected by the second light position detection means. Eccentricity calculating means.

Further, in the eccentricity measuring method according to the second aspect of the present invention, the measuring light emitted from the light source is divided into a first light and a second light, and these two lights are deviated to the deviation amount of the measuring light in the emitting direction. After the light is guided to produce the same amount of angular displacement,
Only the light is condensed on a predetermined incident optical axis of the test object, and the first light reflected on the test surface of the test object or transmitted through the test object is guided onto the first measurement surface to form a first light spot. And the second light (not reaching the test object) is guided on the second measurement surface to form a second light spot, and the light intensity centroid position of the first light spot and the light intensity of the second light spot The eccentricity of the test object is calculated based on the position of the center of gravity.

In the eccentricity measuring apparatus and the eccentricity measuring method according to the second aspect of the present invention, the measuring light emitted from the light source is transmitted to the first eccentricity measuring apparatus.
After splitting into the light and the second light, only the first light of these two lights is focused on a predetermined incident optical axis of the test object, and is reflected on the test surface of the test object or transmitted through the test object. The first light is guided on the first measurement surface to form a first light spot, and the second light not reaching the test object is guided on the second measurement surface to form a second light spot. Then, the eccentricity of the test object is calculated based on the light quantity centroid position of the first light spot and the light quantity centroid position of the second light spot. Here, since the first and second lights are guided so as to cause the same amount of angular displacement with respect to the amount of deviation of the measurement light in the emission direction, the light quantity centroid position of these first light spots and the second light The eccentricity of the test object obtained based on the position of the center of gravity of the light amount of the spot is a value in which the angular deviation between the two light beams caused by the deviation in the emission direction of the measurement light is offset. For this reason, even when the orientation of the light source is unstable and the emission direction of the measurement light shifts, this does not affect the measurement result, and the eccentricity measurement of the test object can be performed with high accuracy. Become.

A third eccentricity measuring apparatus according to the present invention is characterized in that the light source and the measuring light emitted from the light source are converted into a first light having substantially the same light quantity.
After the light is split into the second light and the second light, the first light has the same amount of shift in the same direction as the shift in the emission direction of the measurement light with respect to the shift in the emission direction of the measurement light. The light is condensed on a predetermined incident optical axis of the test object in a state where the same amount of displacement occurs in the direction opposite to the first light, and the light is reflected on the test surface of the test object or transmitted through the test object. An optical system that guides light on the same measurement surface to form a light spot for each of the light beams, a light position detection unit that detects a position of a center of gravity of a total light amount of both light spots formed on the measurement surface, and a light position detection Eccentricity calculating means for calculating the eccentricity of the test object based on the total light amount centroid position of both light spots detected by the means.

Further, in the third eccentricity measuring method according to the present invention, the eccentricity measuring light emitted from the light source is converted into a first light having substantially the same light amount.
After splitting the light into the second light, the first light has the same amount of shift in the same direction as the shift in the emission direction of the measurement light with respect to the shift in the emission direction of the measurement light. The light is condensed on a predetermined incident optical axis of the test object in a state where the same amount of displacement occurs in the direction opposite to the first light, and the light is reflected on the test surface of the test object or transmitted through the test object. The light is guided on the same measurement surface to form a light spot for each light, and the eccentricity of the test object is calculated based on the position of the center of gravity of the total light amount of both light spots.

In the eccentricity measuring device and the eccentricity measuring method according to the third aspect of the present invention, the measuring light emitted from the light source is transmitted to the first eccentricity measuring device.
After splitting the light into the light and the second light, these two lights are condensed on a predetermined incident optical axis of the test object, and both lights reflected on the test surface of the test object or transmitted through the test object are the same. The light is guided on the measurement surface to form a light spot for each of the two lights, and the eccentricity of the test object is calculated based on the position of the center of gravity of the total light amount of the two light spots. Here, the first light and the second light are adjusted so that the light amounts of both light beams are substantially equal at the time of division, and the first light is emitted in the emission direction of the measurement light with respect to the shift in the emission direction of the measurement light. Since the same amount of shift occurs in the same direction as the shift, and the second light is guided to the subject in such a manner as to cause the same amount of shift in the direction opposite to the first light. The eccentricity of the test object obtained based on the position of the center of gravity of the total light quantity of both light spots is a value in which the angle shift between the two light beams caused by the shift in the emission direction of the measurement light is offset. For this reason, even when the orientation of the light source is unstable and the emission direction of the measurement light shifts, this does not affect the measurement result, and the eccentricity measurement of the test object can be performed with high accuracy. Become.

According to a fourth aspect of the present invention, an eccentricity measuring apparatus divides a measuring light emitted from a light source into a first light and a second light, and then deviates both of these lights in the measuring light emitting direction. The light is condensed on the predetermined incident optical axis of the test object in such a state that the same amount of angular displacement occurs with respect to the amount, and the light is reflected on the test surface of the test object or transmitted through the test object. An optical system for guiding one light on a first measurement surface to form a first light spot and guiding the second light on a second measurement surface to form a second light spot; and a first measurement surface. First light position detecting means for detecting the light quantity centroid position of the first light spot formed thereon, and second light for detecting the light quantity centroid position of the second light spot formed on the second measurement surface. A position detecting means, a light quantity centroid position of the first light spot detected by the first light position detecting means, and a second light position detecting means; And a eccentricity calculating means for calculating the eccentricity of the test object on the basis of the light quantity gravity center position of the second light spot detected by the means.

Further, in the eccentricity measuring method according to the fourth aspect of the present invention, the measuring light emitted from the light source is divided into a first light and a second light, and these two lights are shifted in the emitting direction of the measuring light. Is converged on a predetermined incident optical axis of the test object in such a state that the same amount of angular displacement occurs, and the first of the two lights reflected or transmitted through the test object on the test surface of the test object. Guiding the light onto the first measurement surface to form a first light spot, and guiding the second light onto the second measurement surface to form a second light spot;
The eccentricity of the test object is calculated based on the light quantity centroid position of the first light spot and the light quantity centroid position of the second light spot.

In the eccentricity measuring device and the eccentricity measuring method according to the fourth aspect of the present invention, the measuring light emitted from the light source is transmitted to the first eccentricity measuring device.
After splitting the light into the second light, the two lights are condensed on a predetermined incident optical axis of the test object, and the two lights are reflected on the test surface of the test object or transmitted through the test object. One light is guided on the first measurement surface to form a first light spot, and
The light is guided on the second measurement surface to form a second light spot, and the eccentricity of the test object is calculated based on the light quantity centroid position of the first light spot and the light quantity centroid position of the second light spot. Here, the first and second lights are led to the test object in such a state that the same amount of angular displacement is generated with respect to the amount of deviation of the measurement light in the emission direction. The eccentricity of the test object obtained based on the position of the center of gravity of the light quantity of the spot and the position of the center of gravity of the quantity of light of the second light spot is a value in which the angular displacement between the two lights caused by the displacement of the measuring light in the emission direction is offset. Becomes For this reason, even when the orientation of the light source is unstable and the emission direction of the measurement light shifts, this does not affect the measurement result, and the eccentricity measurement of the test object can be performed with high accuracy. Become.

An eccentricity measuring apparatus according to a fifth aspect of the present invention divides a measuring light emitted from a light source and transmitted through a focus lens system into a first light and a second light having substantially equal light amounts. These two lights are first shifted with respect to the displacement of the measurement light in the emission direction.
The focus lens system is adjusted so that the light has the same amount of shift in the same direction as the measurement light emission direction and the second light has the same amount of shift in the direction opposite to the first light. The light is condensed on a predetermined incident optical axis of the test object, and both lights reflected on the test surface of the test object or transmitted through the test object are guided on the same measurement surface to form respective light spots of both lights. An optical system to be detected, light position detecting means for detecting the position of the center of gravity of the total light quantity of both light spots formed on the measurement surface, and Eccentricity calculating means for calculating eccentricity of the test object based on the amount of deviation. Here, the reference position is a position where the position of the center of gravity of the total light amount of both light spots on the measurement surface when the test object has no eccentricity (the same applies to the following method).

Further, in the eccentricity measuring method according to the fifth aspect of the present invention, the measuring light emitted from the light source and transmitted through the focus lens system is divided into first light and second light having substantially equal light amounts, The first and second light beams are first shifted with respect to the deviation of the measurement light emission direction.
The focus lens system is adjusted so that the light has the same amount of shift in the same direction as the measurement light emission direction and the second light has the same amount of shift in the direction opposite to the first light. The light is condensed on a predetermined incident optical axis of the test object, and both light reflected on the test surface of the test object or transmitted through the test object is guided on the same measurement surface to form respective light spots of both lights. Then, the eccentricity of the test object is calculated based on the amount of deviation of the center of gravity of the total light amount of both light spots from the reference position.

In the eccentricity measuring apparatus and the eccentricity measuring method according to the fifth aspect of the present invention, the measuring light emitted from the light source and transmitted through the focus lens system is divided into a first light and a second light. Both lights are adjusted by the focus lens system and focused on a predetermined incident optical axis of the test object, and both lights reflected on the test surface of the test object or transmitted through the test object on the same measurement surface. To form a light spot for each of the two light spots, and calculate the eccentricity of the test object based on the amount of deviation of the center of gravity of the total light quantity of both light spots from the reference position. Here, the first and second
The two light beams are adjusted so that the light amounts of the two beams are substantially equal at the time of division, and the first light beam has the same amount of displacement in the same direction as the displacement direction of the measurement light beam with respect to the displacement of the measurement light beam in the emission direction. And the second light is guided to the test object in such a manner that the second light is shifted by the same amount in the direction opposite to the first light. The eccentricity of the test object obtained based on the deviation amount from the position is a value in which the angular deviation between the two light beams caused by the deviation in the emission direction of the measurement light is offset. For this reason, even if the orientation of the light source is unstable and the emission direction of the measurement light shifts, or the optical axis of the focus lens system shifts, this does not affect the measurement result, and the bias of the test object is not affected. The core measurement can be performed with high accuracy.

Further, since the measurement light passes through the focus lens system before being split, the angle shift between the two lights caused by the optical axis shift of the focus lens system is also canceled out. Becomes Therefore, even when the optical axis shift of the focus lens system occurs, this does not affect the measurement result, and the eccentricity measurement of the test object can be performed with higher accuracy. In addition, since there is no measurement error due to the optical axis shift of the focus lens system, there is no need to rotate the test object around the optical axis, and the measurement work efficiency is improved. Furthermore, since a device for rotating the test object is not required, the measurement accuracy is improved, and the cost can be reduced.

According to a sixth aspect of the present invention, the eccentricity measuring device divides the measuring light emitted from the light source and transmitted through the focus lens system into the first light and the second light, and then splits the two lights. The focus lens system is adjusted in such a state that the same amount of angular displacement is generated with respect to the amount of deviation of the measurement light in the emission direction, and the light is condensed on a predetermined incident optical axis of the test object, and the test surface of the test object is measured. Of the two lights reflected or transmitted through the test object at the first
An optical system for guiding the second light on the second measurement surface to form a first light spot while guiding the second light spot on the second measurement surface, and an optical system formed on the first measurement surface. First
First light position detecting means for detecting the light quantity centroid position of the light spot; second light position detecting means for detecting the light quantity centroid position of the second light spot formed on the second measurement surface;
Of the first light spot detected by the second light position detecting means from the reference position and the second light spot detected by the second light position detecting means deviate from the reference position. Eccentricity calculating means for calculating the eccentricity of the test object based on the amount. Here, the reference position is a position where the center of gravity of the amount of light of the first light spot is located on the first measurement surface and the position of the center of gravity of the amount of light of the second light spot when the test object has no eccentricity. It is a position located on the surface (the same applies to the following method).

Further, in the eccentricity measuring method according to the sixth aspect of the present invention, the measuring light emitted from the light source and transmitted through the focus lens system is divided into a first light and a second light. Focused on a predetermined incident optical axis of the test object by adjusting the focus lens system in such a state that the same amount of angular shift is generated with respect to the amount of shift of the measurement light in the emission direction, and on the test surface of the test object Of the two lights reflected or transmitted through the test object, the first light is guided on the first measurement surface to form a first light spot, and the second light is guided on the second measurement surface to form the second light A spot is formed, and the eccentricity of the test object is calculated based on the amount of deviation of the center of gravity of the light amount of the first light spot from the reference position and the amount of deviation of the center of gravity of the amount of light of the second light spot from the reference position.

In the eccentricity measuring apparatus and the eccentricity measuring method according to the sixth aspect of the invention, the measuring light emitted from the light source and transmitted through the focus lens system is divided into a first light and a second light. The two lights are adjusted by the focus lens system and condensed on a predetermined incident optical axis of the test object, and the first light of the two lights reflected on the test surface of the test object or transmitted through the test object is converted to the first light. The first light spot is guided on the second measurement surface to form a light spot, and the second light is guided on the second measurement surface to form a light spot. The eccentricity of the test object is calculated based on the amount of displacement of the center of gravity of the light amount of the second light spot from the reference position. Here, the first and second lights are guided to the test object in such a state that the same amount of angular displacement is generated with respect to the amount of deviation of the measurement light in the emission direction. The eccentricity of the test object obtained based on the amount of deviation of the center of gravity of the light amount of the spot from the reference position and the amount of deviation of the center of gravity of the light amount of the second light spot from the reference position is determined by the deviation in the emission direction of the measurement light. This results in a value in which the angle shift between the two lights caused by the light is canceled. Therefore, even when the orientation of the light source is unstable and the emission direction of the measurement light is shifted, the measurement result is not affected, and the eccentricity measurement of the test object can be performed with high accuracy. .

Further, since the measurement light passes through the focus lens system before being split, the angle shift between the two lights caused by the optical axis shift of the focus lens system is also canceled out. Becomes Therefore, even when the optical axis shift of the focus lens system occurs, this does not affect the measurement result, and the eccentricity measurement of the test object can be performed with higher accuracy. In addition, since there is no measurement error due to the optical axis shift of the focus lens system, there is no need to rotate the test object around the optical axis, and the measurement work efficiency is improved. Furthermore, since a device for rotating the test object is not required, the measurement accuracy is improved, and the cost can be reduced.

In the eccentricity measuring apparatus, the position of the condensed light may be a position in the vicinity of the center of curvature of the surface of the test object or a position of the surface of the test object when the condensed light is reflected on the surface of the test object. It is a position near the paraxial focal point, and when the test object is transmitted, it is preferably a position near the front focus of the test object.
Further, it is preferable that the test object is held by a holding member (for example, a rotary table in the embodiment) having a function of rotating the test object around the optical axis. The optical system preferably has an optical member having a function of reflecting one of the first light and the second light in the incident direction. Further, the above division is performed by a polarizing beam splitter or a transmissive / reflective member (for example, the reflective / transmissive plate 4 in the embodiment).
0) is preferred.

In the eccentricity measuring method, the condensing position may be a position in the vicinity of the center of curvature of the test surface or a position of the test surface when the condensed light is reflected on the test surface of the test object. It is a position near the paraxial focal point, and when the test object is transmitted, it is preferably a position near the front focus of the test object.
Further, it is preferable that the test object is held by a holding member (for example, a turntable in the embodiment) having a function of rotating the test object around the optical axis. In addition, the first light has the same amount of shift in the same direction as the measurement light emission direction shift with respect to the measurement light emission direction shift, and the second light has the same amount in the direction opposite to the first light. The state that causes the shift is
It is preferable that the first light or the second light is formed by an optical member having a function of reflecting the light in the incident direction. Further, in the eccentricity measuring method according to the second, fourth or sixth aspect of the present invention, the first light is shifted in the same direction as the emission direction of the measuring light, and the second light is opposite to the first light. It is preferable that a shift occurs in the direction of.
Preferably, the division is performed by a polarizing beam splitter or a transmissive / reflective member (for example, the reflective / transmissive plate 40 in the embodiment).

A projection lens incorporating an optical element whose eccentricity has been measured using the eccentricity measuring device or method described above is an extremely high-precision optical component with little eccentricity.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below. First, an eccentricity measuring device and an eccentricity measuring method according to the first invention will be described. FIG. 1 shows the first embodiment of the eccentricity measuring apparatus according to the first invention, and is an example in the case of measuring the reflection eccentricity of a test object 91 which is a convex lens. In this eccentricity measuring device, the light source 1
1 (for example, a laser light source) is condensed by a lens 12 and an index 13 located at the converging point
And enters the collimator lens 14. The measurement light converted into a parallel light by the collimator lens 14 proceeds further downward in the drawing and enters the beam splitter 20.

The measuring light that has entered the beam splitter 20 passes through the semi-permeable membrane and proceeds as it is in the lower part of the figure. An image of the index 13 is projected on the reflection surface of the plate 40. The reflection / transmission plate 40 is provided so as to be perpendicular to the optical axis of the lens 31 and to have a reflection surface located at the focal point of the lens 31. The reflection / transmission plate 40 is divided into a first light that passes through the reflection surface and travels downward in the figure and a second light that reflects on the reflection surface and travels upward in the figure. The reflectivity of the reflection / transmission plate 40 is adjusted so that the light amounts of the two lights are substantially equal (so that the light amount difference between the two lights is extremely small). The reason is that, as described later, the first
This is because the barycentric position of the total light amount is calculated based on the light spot of the light and the light spot of the second light, so that if the light amounts of the respective lights are different, the barycentric position is shifted.

The first light that has passed through the reflection / transmission plate 40 and travels downward in the drawing is converted into parallel light by the collimator lens 32, and then the focus lens system 60 near the center of curvature of the object 91 (or paraxial). (The position near the focal point), whereby the image of the index 13 is projected on the surface of the test object 91 to be measured. Here, the focus lens system 60 is composed of a movable lens 61 composed of a biconvex lens and a fixed lens 62 composed of a biconcave lens. By moving the movable lens 61 in the optical axis direction of the test object 91, It is possible to position the focal position of one light at a desired position on the optical axis.

The first light condensed at a position near the center of curvature of the test object 91 is reflected on the test surface of the test object 91,
The light enters from below the focus lens system 60 (below in the drawing), passes through the collimator lens 32, the reflection / transmission plate 40, and the lens 31, and further reflects on the semi-permeable film of the beam splitter 20, and proceeds to the right in the drawing. Then, the light is condensed by a lens 33 installed on the right side (the right side in the drawing) of the beam splitter 20 to form a light spot on the measurement surface (the light receiving surface of the light position detecting element 70). On the other hand, the second light reflected by the reflection / transmission plate 40 and traveling upward in the drawing returns on the same optical path as when entering the reflection / transmission plate 40, and is reflected by the semi-permeable film of the beam splitter 20 like the first light. And go to the right of the figure. Then, the light is condensed by the lens 32 and forms a light spot on the same measurement surface as the first light.

As described above, the measurement light emitted from the light source 11 is split by the reflection / transmission plate 40 into the first light which is the transmitted light and the second light which is the reflected light. After the light is normally reflected on the surface to be inspected 91, the light passes through the reflection / transmission plate 40 and returns to the beam splitter 20, whereas the second light is reflected by the incident optical path due to the above positional relationship between the lens 31 and the reflection / transmission plate 40. Since the light path returns to the beam splitter 20 after being specially reflected (reflecting the light in the incident direction) so that the first and second lights are superimposed, the first and second lights are superimposed on the right side of the drawing from the beam splitter 20. When the first light is emitted, the first light has the same amount of shift in the same direction as the measurement light emission direction shift with respect to the measurement light emission direction shift caused by the unstable posture of the light source 11. Two lights are in the opposite direction to the first It is adapted to produce a shift.
That is, as shown in FIG. 2, when the measurement light L emitted from the light source 11 is shifted by an angle θ from a reference direction (here, the direction of a predetermined incident optical axis of the test object 91 and indicated by a dashed line). , The first light L1 also has an angle shift by the same amount (angle θ), and the second light has an angle shift by the same amount (angle θ) in the direction opposite to the first light L1.

The light position detecting element 70 has a light receiving surface (measurement surface).
The position of the center of gravity of the total light amount of both light spots formed above is detected, and the result is output to the eccentricity calculator 80. The eccentricity calculator 80 determines the position of the test object 9 based on the amount of deviation between the detected center of gravity of the total light amount of both light spots and a predetermined reference position.
1 is calculated and displayed on a display or the like.
Here, the reference position is a position where the center of gravity of the total light amount of both light spots is located on the measurement surface when the test object 91 is not eccentric. When the test object 91 is not eccentric, the optical axis (reflection optical axis) when reflected on the test surface of the test object 91 and the optical axis when the first light is incident on the test object 91. (Incident optical axis), and the light quantity centroid position of the light spot formed solely on the measurement surface by the first light and the light quantity centroid position of the light spot formed solely on the measurement surface by the second light are both reference positions. (For this reason, the center of gravity of the total light amount of both light spots also matches the reference position), but when the test object 91 is eccentric, the reflected optical axis does not match the incident optical axis (angle Because of the shift, the center of gravity of the light amount of the light spot formed solely by the first light on the measurement surface is shifted from the reference position (the center of gravity of the total light amount of both the first and second lights is It will be shifted from the reference position).

If the attitude of the light source 11 is unstable and the emission direction of the measurement light is deviated from the reference direction (here, the direction of the predetermined incident optical axis of the test object 91), the test object 91
Irrespective of the eccentricity of the first light, the incident light axis of the first light with respect to the test object 91 does not coincide with the reflected light axis, so that the first light reflected by the test surface of the test object 91 is on the measurement surface. The light quantity centroid position of the light spot formed alone and the light quantity centroid position of the light spot formed solely on the measurement surface by the second light are both shifted from the reference position.

Here, as described above, the first and second lights are adjusted so that the light amounts of the first and second lights are substantially equal at the time of division on the reflection / transmission plate 40, and the first light and the second light are adjusted with respect to the deviation in the emission direction of the measurement light. The first light has the same amount of displacement in the same direction as the measurement light exit direction, and the second light has the same amount of displacement in the opposite direction to the first light. Therefore, the position of the center of gravity of the light spot of the first light spot formed on the measurement surface and the position of the center of light quantity of the light spot of the second light spot are shifted by the same amount in the opposite direction to the shift of the measurement light emission direction. In addition, the light amounts of both light spots are equal. For this reason, the eccentricity of the test object 91 obtained based on the shift amount of the center of gravity of the total light amount between the light spot of the first light and the light spot of the second light formed on the measurement surface from the reference position is The angle deviation between the two light beams caused by the deviation in the emission direction of the measurement light is a value that cancels out. Even if the attitude of the light source 11 is unstable and the emission direction of the measurement light is deviated, this affects the measurement result. Never reach.

However, as in this example, the focus lens system 60 divides the measurement light (here, the reflection / transmission plate 4
In the eccentricity measuring device installed downstream of (0), when the focus lens system 60 has an optical axis shift (the optical axis of the movable lens 61 does not match the optical axis of the fixed lens 62). Irrespective of the eccentricity of the test object 91,
Since the reflected light axis of the light on the test object 91 no longer coincides with the incident optical axis, the position of the light quantity center of gravity of the light spot formed solely on the measurement surface by the first light reflected on the test surface of the test object 91 is It is shifted from the reference position. For this reason, when measuring the eccentricity of the test object 91 using this device, the test object 9
By rotating a turntable (not shown) for holding the test object 1
It is necessary to rotate 1 around the optical axis, and to observe whether or not the position of the center of gravity of the total light quantity fluctuates accordingly (whether it rotates around the reference position). Here, when the position of the center of gravity of the total light amount does not fluctuate with the rotation of the test object 91, the deviation from the reference position is not due to the eccentricity of the test object 91 but to the optical axis deviation of the focus lens system 60. It turns out that.

FIG. 3 shows a second embodiment of the eccentricity measuring apparatus according to the first invention. The eccentricity measuring apparatus according to this embodiment is an example of measuring the transmission eccentricity of a test object 92 which is a concave lens. The device according to this embodiment has the basic configuration shown in the first embodiment described above. The difference is that it is installed perpendicular to the incident optical axis. In such a configuration, when measuring the transmission eccentricity of the test object 92 which is a concave lens,
The first light split by the reflection / transmission plate 40 is collected by the focus lens system 60 at a position near the front focus of the test object 92.

As a result, the first light transmitted through the test object 92 becomes parallel light and is incident on the reflection mirror 34, and the test object 91
Is not eccentric, the optical axis (reflected optical axis) when the first light is reflected by the reflecting mirror 34 is the optical axis (incident optical axis) when the first light is incident on the reflecting mirror 34. , And the light intensity centroid position of the light spot formed solely on the measurement surface by the first light coincides with the reference position. However, the test object 92
Is eccentric, the reflected optical axis does not coincide with the incident optical axis (causes an angular deviation), and the center of gravity of the light quantity of the light spot formed solely on the measurement surface by the first light is from the reference position. It is shifted.

The measurement light emitted from the light source 11 is split by the reflection / transmission plate 40 into the first light, which is transmitted light, and the second light, which is reflected light. When the light is emitted to the right in the drawing, the first light is shifted by the same amount in the same direction as the emission direction of the measurement light with respect to the emission direction shift of the measurement light caused by the unstable posture of the light source 11. , And the second light is shifted by the same amount in the opposite direction to the first light, as in the case of the first embodiment. For this reason, also in the eccentricity measuring device according to the present embodiment, the same effect as in the case of the eccentricity measuring device according to the first embodiment can be obtained.

FIG. 4 shows a third embodiment of the eccentricity measuring apparatus according to the first invention, which is another example in the case of measuring the reflection eccentricity of a test object 93 which is a convex lens. The eccentricity measuring apparatus according to this embodiment is provided with a deflection beam splitter 21 instead of the beam splitter 20 in the first embodiment (FIG. 1), and to the left of the deflection beam splitter 21 (to the left in the figure). After a quarter-wave plate 35 is installed, a lens 36 and a reflection mirror 37 are installed on the left side (left side in the figure) so that a reflection surface is located at the focal position of the lens 36. The lens 31, the reflection / transmission plate 40, and the collimator lens 32 provided between the splitter 20 and the focus lens system 60 are removed, and a quarter wavelength plate 38 is provided instead.

In the eccentricity measuring device having such a configuration,
The measurement light converted into parallel light by the collimator lens 14 is incident on the polarization beam splitter 21 and includes a first light that is P-polarized light transmitted through the semi-permeable film and a second light that is S-polarized light reflected on the semi-permeable film. Is divided into Here, the state of light incident on the polarization beam splitter 21 is adjusted, and the first
The light amounts of the light and the second light are set to be substantially equal (so that the light amount difference between the two lights is extremely small).

The first light that has passed through the semi-permeable film of the polarizing beam splitter 21 proceeds to the lower part of FIG.
8, the light is condensed by the focus lens system 60 at a position near the center of curvature of the test object 91, and an image of the index 13 is projected on the test surface of the test object 91. Since the first light condensed at a position near the center of curvature of the test object 91 is perpendicularly incident on the test surface of the test object 91, the first light reflected on the test surface of the test object 91 is reflected. After returning through the same optical path as at the time of incidence and passing through the focus lens system 60 and the quarter-wave plate 38, the light enters the polarization beam splitter 21 from below in the figure.

Here, the first light is a polarized beam splitter 2
Although the light was P-polarized light when it was transmitted downward, the １ ／ wavelength plate 38 was moved twice before being reflected on the surface of the test object 91 and returning to the polarization beam splitter 21 again. Since the light passes through the polarization beam splitter 21 from below, it is S-polarized. Therefore, the first light is reflected by the semi-permeable film of the polarizing beam splitter 21 and proceeds to the right in the drawing. Then, the light is condensed by the lens 33 located to the right (to the right in the drawing) of the deflection beam splitter 21 and is measured (the light receiving surface of the light position detecting element 70).
Form a light spot on top.

On the other hand, the second light reflected on the semi-permeable film of the polarization beam splitter 21 advances to the left in the figure, passes through the quarter-wave plate 35, is condensed by the lens 36, and The light is reflected by the located reflection mirror 37. Then, the light again passes through the lens 36 and the quarter-wave plate 35 and enters the polarization beam splitter 21 from the left side in the drawing. Here, the second light was S-polarized light when reflected on the semi-permeable film of the polarization beam splitter 21 to the left in the figure, but was reflected by the reflection mirror 37 and returned to the polarization beam splitter 21 again. Between the two quarter-wave plates 35
Since the light passes through the polarization beam splitter 21 from the left, the light is P-polarized light. Therefore, the second light passes through the semi-permeable membrane of the polarization beam splitter 21 as it is and travels rightward, is collected by the lens 33, and forms a light spot on the same measurement surface as the first light.

As described above, the measurement light emitted from the light source 11 is transmitted by the polarization beam splitter 21 to the first light.
Although the light is split into light and second light that is reflected light, the first light normally reflects on the surface of the test object 91 and then normally reflects on the semi-permeable film of the deflecting beam splitter 21. On the other hand, in the second light that has not reached the test object 91, the incident light path and the reflected light path become parallel (reflect the light in the incident direction) due to the above positional relationship between the lens 36 and the reflection mirror 37.
After the special reflection, the light is normally reflected by the semi-permeable membrane of the deflection beam splitter 21. Therefore, when the first and second lights are superimposed and emitted from the deflection beam splitter 21 to the right, the light source 11 Of the measurement light caused by the unstable posture of the measuring beam.
The light has the same amount of shift in the same direction as the measurement light emission direction shift, and the second light has the same amount of shift in the direction opposite to the first light. Therefore, the eccentricity measuring device according to the present embodiment can also obtain the same effects as those of the eccentricity measuring device according to the first embodiment.

FIG. 5 shows a fourth embodiment of the eccentricity measuring apparatus according to the first invention. The eccentricity measuring apparatus according to this embodiment is another example of measuring the transmission eccentricity of the test object 94 which is a concave lens. The device according to this embodiment is:
The basic configuration is the configuration shown in the above-described third embodiment. However, a flat reflecting mirror 34 is provided below the test object 94 (downward in the drawing) so as to be perpendicular to a predetermined incident optical axis of the test object 94. The installed point is different. In such a configuration, when measuring the transmission eccentricity of the test object 94 which is a concave lens, the first light split by the deflection beam splitter 21 is focused by the focus lens system 60 on the front focus of the test object 94. Light is collected at a nearby position. Accordingly, the first light transmitted through the test object 94 becomes parallel light and enters the reflection mirror 34, and thereafter, the first and second lights behave in the same manner as described in the third embodiment. .

The measuring light emitted from the light source 11 is split by the deflection beam splitter 21 into a first light which is a transmitted light and a second light which is a reflected light. When the light is emitted to the right in the drawing, the first light has the same amount in the same direction as the displacement of the measurement light due to the displacement of the measurement light due to the unstable orientation of the light source 11. Causes a shift and the second
The light shifts by the same amount in the direction opposite to the first light as in the third embodiment. For this reason, in the eccentricity measuring device according to the present embodiment, the same effect as that of the eccentricity measuring device according to the third embodiment (that is, the same effect as the eccentricity measuring device according to the first embodiment) is obtained. Can be.

As described above, in the eccentricity measuring apparatus and the eccentricity measuring method according to the above procedure according to the first invention, the light source 1
After dividing the measurement light emitted from 1 into a first light and a second light, only the first light of these two lights is condensed on a predetermined incident optical axis of the test object by the focus lens system 60, Guiding the first light that has been reflected or transmitted through the test object on the test surface of the test object and the second light that has not reached the test object on the same measurement surface to form a light spot for each of the two lights; The eccentricity of the test object is calculated based on the shift amount of the center of gravity of the total light amount of both light spots from the reference position. Here, the first light and the second light are adjusted so that the light amounts of both light beams are substantially equal at the time of division, and the first light is emitted in the emission direction of the measurement light with respect to the shift in the emission direction of the measurement light. Since the same amount of displacement occurs in the same direction as the displacement, and the second light is guided on the measurement surface in such a manner as to produce the same amount of displacement in the direction opposite to the first light. The eccentricity of the test object obtained based on the shift amount of the center of gravity of the total light quantity of both light spots from the reference position is a value in which the angular shift of both lights caused by the shift of the measurement light emission direction is offset. Becomes Therefore, the light source 1
Even in the case where the posture of the sample 1 is unstable and the emission direction of the measurement light shifts, this does not affect the measurement result, and the eccentricity measurement of the test object can be performed with high accuracy.

Although the above-described embodiments correspond only to the case where the reflection eccentricity of the test object which is a convex lens is measured and the case where the transmission eccentricity of the test object which is a concave lens is measured. By appropriately rearranging the configuration of the optical system of the above embodiment, it is possible to measure the transmission eccentricity of the test object which is a convex lens, and also to measure the reflection eccentricity of the test object which is a concave lens. is there.

Next, an eccentricity measuring apparatus and an eccentricity measuring method according to a second embodiment of the present invention will be described. FIG. 6 shows an embodiment of the eccentricity measuring apparatus according to the second aspect of the present invention, which is an example in the case of measuring the reflection eccentricity of a test object 191 which is a convex lens. In this eccentricity measuring device, the light source 11
The measurement light emitted from 1 is condensed by a lens 112 and enters a collimator lens 114 via an index 113 located at the condensing point. The measurement light converted into parallel light by the collimator lens 114 further proceeds in the lower part of the figure and enters the polarization beam splitter 121, where the first light, which is P-polarized light, passes through the semi-permeable film, and S, which is reflected at the semi-permeable film. It is split into the second light that is polarized light. Here, unlike the eccentricity measuring apparatus according to the first aspect of the present invention, it is not necessary to make the light amounts of the first and second lights substantially equal. The reason is that, as will be described later, the center of gravity of the amount of light of the first light spot (first light spot) and the center of the amount of light of the second light spot (second light spot) are calculated separately. This is because the position of the center of gravity does not depend on the light amount balance between the first light and the second light.

The first light that has passed through the semi-permeable film of the polarizing beam splitter 121 proceeds directly downward in the drawing, passes through the quarter-wave plate 131, and then moves to the movable lens 1 composed of a biconvex lens.
The light is condensed at a position near the center of curvature of the test object 191 (or near a paraxial focal point) by a focus lens system 160 composed of a fixed lens 162 formed of a biconcave lens and a surface of the test object 191. Is an image of the index 113 is projected. Here, in the focus lens system 160, the movable lens 161 is movable in the optical axis direction, whereby the focal position of the first light can be located at a desired position on the optical axis. The first light condensed at a position near the center of curvature of the test object 191 is reflected on the test surface of the test object 191 and then enters from below the focus lens system 160 (lower in the figure) and becomes 1/4. After passing through the wave plate 131, the light enters the polarization beam splitter 121 from below in the figure.

Here, the first light is the polarized beam splitter 1
Although the light was P-polarized light at the time of transmitting the light downward, the １ ／ wavelength plate 131 was moved twice before being reflected by the surface of the test object 191 and returning to the polarizing beam splitter 121 again. Since the light passes through the polarization beam splitter 121 from below, it is S-polarized. Therefore, the first light is reflected by the semi-permeable film of the polarizing beam splitter 121 and proceeds to the right in the drawing. Then, the light is condensed by the lens 132 located on the right side (the right side in the drawing) of the deflection beam splitter 121 and is collected on the first measurement surface (the first measurement surface).
A first light spot is formed on the light receiving surface of the light position detecting element 171). On the other hand, the second light reflected on the semi-permeable film of the polarizing beam splitter 121 proceeds to the left in the figure, and is condensed by the lens 133 located on the left side (left side in the figure) of the deflecting beam splitter 121, and becomes the second light. A second light spot is formed on the measurement surface (the light receiving surface of the second light position detection element 172).

As described above, the measuring light emitted from the light source 111 is split by the polarizing beam splitter 121 into the first light, which is transmitted light, and the second light, which is reflected light. After normal reflection on the surface of the test object of 191,
The second light that has not reached the test object 191 normally reflects only on the semi-permeable film of the polarizing beam splitter 121, while the semi-permeable film of the deflection beam splitter 121 normally reflects the light. The first light has the same amount of shift in the same direction as the measurement light emission direction shift with respect to the measurement light emission direction shift due to instability.
The second light is shifted by the same amount in the direction opposite to the first light.

The first light position detecting element 171 detects the center of gravity of the light quantity of the first light spot formed on the light receiving surface (first measurement surface), and outputs the result to the eccentricity calculator 180. Further, the second light position detecting element 172 has a light receiving surface (second light receiving surface).
Of the second light spot formed on the (measurement surface) is detected, and the result is output to the eccentricity calculator 180 in the same manner. The eccentricity calculator 180 is provided with the first optical position detecting element 1
The light quantity centroid of the second light spot detected by the second light position detection element 172 from the shift angle of the first light obtained based on the shift amount of the light quantity centroid position of the first light spot from the reference position detected by the first light spot 71 The eccentricity of the test object 191 is calculated by subtracting the shift angle of the second light obtained based on the shift amount of the position from the reference position, and this is displayed on a display or the like.

Here, the reference position is the position of the light spot formed on the first measurement surface by the first light reflected on the surface of the test object 191 when the test object 191 has no eccentricity. The light quantity centroid position and the light quantity centroid position of the light spot formed on the second measurement surface by the second light. When the test object 191 is not eccentric, the optical axis (reflection optical axis) when reflecting on the test surface of the test object 191 is the optical axis when the first light is incident on the test object 191. (Incident optical axis), the first light spot formed on the first measurement surface by the first light has the light quantity centroid position coincident with the reference position, and the second light is formed on the second measurement surface. The light intensity centroid position of the second light spot also matches the reference position. However, when the test object 191 is eccentric, the reflected optical axis does not coincide with the incident optical axis (causes an angular deviation), so that the first light formed on the first measurement surface by the first light is not reflected. The light intensity barycentric position of the light spot is shifted from the reference position.

Also, the attitude of the light source 111 is unstable,
The emission direction of the measurement light is the reference direction (here, the test object 191).
(In the direction of the predetermined incident optical axis), the reflected light axis of the first light on the test object 191 does not coincide with the incident optical axis regardless of the eccentricity of the test object 191. The center of gravity of the light quantity of the first light spot formed by the first light reflected on the surface to be inspected of the inspection object 191 on the first measurement surface is shifted from the reference position, and the second light is transmitted to the second measurement surface. The light quantity centroid position of the second light spot formed above is also shifted from the reference position.

Here, as described above, the first light and the second light have the same amount of displacement in the same direction as the displacement of the measurement light with respect to the displacement of the measurement light with respect to the displacement of the measurement light. , The second light is guided so as to generate the same amount of shift in the direction opposite to the first light, so that the shift of the light quantity centroid position of the first light spot formed on the first measurement surface from the reference position Quantity and the second
The amount of deviation of the center of gravity of the light amount of the second light spot formed on the measurement surface from the reference position is the same as the deviation of the measurement light in the emission direction. For this reason, based on the shift amount of the light quantity centroid position of the first light spot formed on the first measurement surface from the reference position and the shift quantity of the light quantity centroid position of the second light spot from the reference position (the second light spot). From the shift angle of the first light obtained based on the shift amount of the light quantity centroid position of one light spot from the reference position, the second light obtained based on the shift amount of the light quantity centroid position of the second light spot from the reference position. The eccentricity of the test object obtained by subtracting the deviation angle is a value in which the angular deviation between the two light beams caused by the deviation in the emission direction of the measurement light is offset, and the posture of the light source 111 is unstable and the measurement light This does not affect the measurement result even if the emission direction of the laser beam is shifted.

However, also in this case, similarly to the case of the eccentricity measuring device according to the first aspect of the present invention, the focus lens system 1 is used.
60 is provided downstream of the means for splitting the measurement light (the deflection beam splitter 121 in this case), and this focus lens system 160 has an optical axis shift (movable lens 16
1 does not coincide with the optical axis of the fixed lens 162), regardless of the eccentricity of the test object 191,
Since the reflected light axis of the light on the test object 191 does not coincide with the incident optical axis, the first light reflected on the test surface of the test object 191 is the first light.
The center of gravity of the light amount of the first light spot formed by the light on the first measurement surface is shifted from the reference position. Therefore, when performing eccentricity measurement of the test object 191 using this apparatus, a turntable (not shown) holding the test object 191 is rotated to rotate the test object 191 around the optical axis. Accordingly, it is necessary to observe whether or not the light quantity centroid position of the first light spot fluctuates (rotates around the reference position). Here, when the position of the center of gravity of the light amount of the first light spot does not change with the rotation of the test object 191, the deviation from the reference position is not due to the eccentricity of the test object 191.
This is due to the optical axis shift of the focus lens system 160.

As described above, in the eccentricity measuring apparatus and the eccentricity measuring method according to the second embodiment of the present invention, the light source 1
After splitting the measurement light emitted from 11 into a first light and a second light, only the first light out of these two lights is condensed on a predetermined incident optical axis of the test object, and The first light reflected on the inspection surface (or transmitted through the test object) is guided on the first measurement surface to form a first light spot, and the second light not reaching the test object is subjected to the second measurement. A second light spot is formed by guiding the light spot on the surface, and the test is performed based on the amount of deviation of the center of gravity of the first light spot from the reference position and the amount of deviation of the center of gravity of the second light spot from the reference position. Calculate the eccentricity of the object. Here, since the first and second light beams are guided so as to generate the same amount of angular deviation with respect to the deviation amount of the measurement light in the emission direction, the first light spot is shifted from the reference position of the light amount centroid position. The eccentricity of the test object obtained based on the deviation amount of the light quantity and the deviation amount of the center of gravity of the light amount of the second light spot from the reference position is the angular deviation between the two light spots caused by the deviation in the emission direction of the measuring light. Are offset values. For this reason, even when the orientation of the light source 111 is unstable and the emission direction of the measurement light is shifted, this does not affect the measurement result, and the eccentricity measurement of the test object can be performed with high accuracy. Becomes

Although the above-described embodiment is only for the case where the reflection eccentricity of the test object which is a convex lens is measured, the configuration of the optical system of the above-described embodiment can be appropriately rearranged. It is possible to measure the transmission eccentricity of the test object which is a convex lens, and to measure the transmission eccentricity and the reflection eccentricity of the test object which is a concave lens. Note that, in the above embodiment, the first and second split light beams have the same amount of displacement in the same direction as the measurement light emission direction shift with respect to the measurement light emission direction shift, and the measurement light emission direction shift. The second light is guided so as to generate the same amount of displacement in the direction opposite to the first light, but both lights are guided so as to produce the same amount of angular displacement with respect to the displacement of the measurement light in the emission direction. , It is not always necessary to shift in the opposite directions.

Next, an eccentricity measuring apparatus and an eccentricity measuring method according to the third invention will be described. FIG. 7 shows the first embodiment of the eccentricity measuring apparatus according to the third aspect of the present invention, which is an example of measuring the reflection eccentricity of the test object 291 which is a concave lens. In this eccentricity measuring device, the light source 2
The measurement light emitted from 11 is condensed by the lens 212 and enters the collimator lens 214 via the index 213 located at the condensing point. The measurement light converted into parallel light by the collimator lens 214 proceeds further downward in the figure and enters the polarization beam splitter 221, where the first light, which is P-polarized light transmitted through the semi-permeable film, and the S reflected at the semi-permeable film. It is split into the second light that is polarized light. Here, as in the case of the third embodiment (or the fourth embodiment) according to the first present invention described above, the state of the light incident on the polarization beam splitter 221 is adjusted, and the first light and the second light are adjusted. The light amount with the light is set to be substantially equal (so that the light amount difference between the two lights is extremely small). The reason is that, similarly to the case of the eccentricity measuring apparatus according to the first aspect of the present invention, the center of gravity of the total light amount is calculated from the light spot of the first light and the light spot of the second light formed on the same measurement surface. Therefore, if the light amounts of the respective lights are different, the position of the center of gravity is shifted.

The first light transmitted through the semi-permeable film of the polarization beam splitter 221 proceeds as it is in the lower part of the figure, while the second light reflected by the semi-permeable film of the polarization beam splitter 221 proceeds to the left in the figure and becomes 1 / After passing through the four-wavelength plate 231, the light is condensed by the lens 232 and reflected by the reflection mirror 233 located at the condensing point. And again, the lens 23
The light passes through the two- and quarter-wave plates 231 and enters the polarization beam splitter 221 from the left side in the drawing.

Here, the second light is the polarized beam splitter 2
At the time when the light was reflected to the left in the figure by the semi-permeable film 21, the light was S-polarized light. Since it has passed twice, it is P-polarized when it enters the polarization beam splitter 221 from the left. Therefore, the second light passes through the semi-permeable membrane of the polarizing beam splitter 221 as it is and proceeds rightward, and passes through the quarter-wave plate 234 provided to the right (right side in the drawing) of the polarizing beam splitter 221. Later, reflection mirror 2
At 35 it reflects. Then, again, the ４ wavelength plate 23
4 and enters the polarization beam splitter 221 from the right side of the figure.

Here, the second light is the polarized beam splitter 2
At the time when the semipermeable membrane No. 21 penetrated from the left to the right in the figure, P
Although the light is polarized, it passes through the quarter-wave plate 234 twice before being reflected by the reflection mirror 235 and returning to the polarization beam splitter 221 again. When the light is incident from one side, it is S-polarized. Therefore, the second light is reflected by the semi-permeable film of the polarizing beam splitter 221 and proceeds downward in the drawing in a state where the second light is superimposed on the first light.

The first and second beams emitted below the polarizing beam splitter 221 in the state of being overlapped in this way
The two beams pass through a half-wave plate 236 (or a combination of a quarter-wave plate and an analyzer) installed below the polarizing beam splitter 221 (below in the drawing), and then move into a movable lens composed of a biconvex lens. A focus lens system 260 including a fixed lens 261 and a fixed lens 262 formed of a biconcave lens condenses light at the focal position of the test object 291, and an image of the index 213 is projected on the test surface of the test object 291.
Here, the focus lens system 260 is a movable lens 261
Are movable in the optical axis direction, so that the focal positions of the first and second lights can be located at desired positions on the optical axis. At this time, the first and second lights are polarized by the polarizing beam splitter 237 and the quarter-wave plate 238 installed below the focus lens system 260 (below in the figure).
Through. Further, both the first and second lights traveling downward from the drawing from the polarization beam splitter 221 are １ ／ wavelength plates 236.
, The S-polarized light (second light) is converted to P-polarized light (the amount of light decreases at this time), and the P-polarized light (first light) is also converted to P-polarized light having the same light amount as the S-polarized light. First and second
Both the lights pass through the semi-permeable membrane of the polarizing beam splitter 237.

The two lights condensed at the focal position of the test object 291 are reflected on the test surface of the test object 291 to become parallel lights, pass through the quarter-wave plate 238 again, and pass through the polarization beam splitter 237. Light enters from the bottom of the figure. Here, both the first and second lights are P-polarized light when they pass through the polarizing beam splitter 237 downward, but are reflected on the surface of the test object 291 and are again reflected by the polarizing beam splitter 2.
Until returning to 37, １ ／ wavelength plate 238
Since the light beam passes through the polarization beam splitter 237 from below, the light beam is S-polarized light. Therefore, both of these lights are reflected by the semi-permeable film of the polarizing beam splitter 237 and travel to the right in the drawing. Then, the light is condensed by a lens 239 provided on the right side (the right side in the drawing) of the polarizing beam splitter 237 to form a light spot on the same measurement surface (light receiving surface of the light position detecting element 270).

As described above, the measurement light emitted from the light source 211 is split by the polarization beam splitter 221 into the first light as the transmitted light and the second light as the reflected light, and the test light is superposed. Although the first light is transmitted through the semi-permeable film of the polarizing beam splitter 221 as it is, the incident light path and the reflected light path of the second light are changed due to the positional relationship between the lens 232 and the reflection mirror 233. After a special reflection that becomes parallel (reflects light in the incident direction), the light passes through the semi-permeable film of the deflection beam splitter 221, and is further normally reflected by the reflection mirror 235, and then is transmitted through the semi-permeable film of the polarization beam splitter 221. When the first and second lights are superimposed and emitted from the deflecting beam splitter 221 downward in FIG. The first light has the same amount of shift in the same direction as the shift of the measurement light in the emission direction due to the instability of the measurement light, and the second light is opposite to the first light. The same amount of shift occurs in the direction of. That is, as shown in FIG. 8, the measurement light L emitted from the light source 211 is at an angle θ from a reference direction (here, the direction of a predetermined incident optical axis of the test object 291 and is indicated by a dashed line).
In this case, the first light L1 also has an angle shift of the same amount (angle θ), and the second light has an angle shift of the same amount (angle θ) in the direction opposite to the first light L1. Wake up.

The light position detecting element 270 detects the position of the center of gravity of the total light amount of these two light spots formed on the light receiving surface (measurement surface), and outputs the result to the eccentricity calculator 280. The eccentricity calculator 280 calculates the eccentricity of the test object 291 based on the amount of deviation between the detected center of gravity of the total light amount of both light spots and a predetermined reference position, and displays this on a display or the like. . Here, the reference position is the object 29
When there is no eccentricity in 1, the position of the center of gravity of the total light amount of both light spots is located on the measurement surface. Test object 291
Is not eccentric, the optical axis (reflected optical axis) when the first and second lights are reflected on the surface of the test object 291 is the optical axis when entering the test object 291. (Incident optical axis)
And the center of gravity of the light amount of the light spot formed independently on the measurement surface by the first and second lights respectively coincides with the reference position. However, when the test object 291 is eccentric, the reflected optical axis does not coincide with the incident optical axis (causes an angular deviation), so that both the first and second lights are independently measured on the measurement surface. Both the light quantity centroid positions of the light spots formed above deviate from the reference position (for this reason, the total light quantity centroid position of both the first and second lights deviates from the reference position).

The posture of the light source 211 is unstable,
The emission direction of the measurement light is the reference direction (here, the test object 291).
(In the direction of the predetermined incident optical axis), the reflected light axis of the first light on the test object 291 does not coincide with the incident optical axis regardless of the eccentricity of the test object 291. Both the light quantity centroid positions of the light spots formed by the first and second lights reflected on the surface to be inspected of the inspection object 291 independently on the measurement surface are both shifted from the reference position.

Here, as described above, the first and second lights are adjusted so that the light amounts of the first and second lights are substantially equal at the time of division by the polarizing beam splitter 221, and the first and second lights are adjusted with respect to the deviation in the emission direction of the measuring light. The first light has the same amount of displacement in the same direction as the measurement light exit direction, and the second light has the same amount of displacement in the opposite direction to the first light. Therefore, the position of the center of gravity of the light spot of the first light spot formed on the measurement surface and the position of the center of gravity of the light spot of the second light spot are shifted in the opposite direction and by the same amount with respect to the shift in the emission direction of the measurement light. In addition, the light amounts of both light spots are equal. For this reason, the eccentricity of the test object 291 obtained based on the amount of deviation of the center of gravity of the total light amount of the two light spots formed on the measurement surface from the reference position is caused by the deviation of the measurement light emission direction. The resulting angle shifts of the two lights are offset, and even if the direction of emission of the measurement light is shifted due to the unstable posture of the light source 211, this does not affect the measurement result.

However, also in this case, as in the case of the eccentricity measuring devices according to the first and second aspects of the present invention, the focus lens system 260 uses the means (here, the deflection beam splitter 221) for dividing the measuring light. If the focus lens system 260 has an optical axis shift (the optical axis of the movable lens 261 does not coincide with the optical axis of the fixed lens 262), the focus lens system 260 is positioned downstream. Irrespective of the core, the reflected light axis of the first light on the test object 291 does not coincide with the incident optical axis, so that both the first and second lights reflected on the test surface of the test object 291 are respectively measured. The positions of the light spots formed independently on the top are both shifted from the reference positions. Therefore, when performing eccentricity measurement of the test object 291 using this apparatus, the turntable (not shown) holding the test object 291 is rotated to rotate the test object 291 around the optical axis. Accordingly, it is necessary to observe whether the position of the center of gravity of the total light amount fluctuates (rotates around the reference position). Here, when the position of the center of gravity of the total light amount of the two light spots does not change with the rotation of the test object 291, the deviation from the reference position is not due to the eccentricity of the test object 291, but the light of the focus lens system 260. This is due to axis misalignment.

FIG. 9 shows a second embodiment of the eccentricity measuring apparatus according to the third aspect of the present invention. A cube 240 is installed.
Also in this configuration, the second light transmitted through the quarter-wave plate 231 from right to left passes through the quarter-wave plate 231 from left to right on the same path. The same effect as in the case can be obtained.

FIG. 10 shows a third embodiment of the eccentricity measuring apparatus according to the third invention. In the first embodiment (FIG. 7), the eccentricity measuring device is to the right of the polarization beam splitter 221 (to the right in the drawing). The を wavelength plate 234 and the reflection mirror 235 provided in the above are removed so that the light emitted therefrom is guided to the 波長 wavelength plate 326, and below the polarization beam splitter 221 (below in the figure). Is provided with a 波長 wavelength plate 241 and a reflection mirror 242.
In such a configuration, first, the light from the light source 211 passes through the polarizing beam splitter 221 to pass through the semi-permeable membrane.
The light is split into the first light that is polarized light and the second light that is S-polarized light reflected on the semi-permeable film. Then, the first light transmits through the quarter-wave plate 241, is reflected by the reflection mirror 242, passes through the quarter-wave plate 241 again, and enters the polarization beam splitter 221 from below in the figure. Here, the first light was P-polarized light when transmitted through the polarizing beam splitter 221 downward, but was reflected by the reflection mirror 242 and returned to the polarizing beam splitter 221 again to be a 波長 wavelength plate. 241 twice, when entering the polarization beam splitter 221 from below, S
It is polarized. Therefore, the first light is reflected by the semi-permeable film of the polarizing beam splitter 221 and proceeds to the right in the drawing.

On the other hand, the second light reflected by the polarization beam splitter 221 and traveling to the left in the drawing is
After passing through 1, the light is condensed by the lens 232 and reflected by the reflection mirror 233 located at the condensing point. Then, the light again passes through the lens 232 and the quarter-wave plate 231 and enters the polarization beam splitter 221 from the left side in the drawing. Here, the second light was s-polarized light when reflected by the semi-permeable film of the polarizing beam splitter 221, but was １ ／ of the time before being reflected by the reflecting mirror 233 and returning to the polarizing beam splitter 221 again. Since the light passes through the wave plate 231 twice, the light is P-polarized when the light enters the polarization beam splitter 221 from the left. Therefore, the second light passes through the polarizing beam splitter 210 from left to right as it is, and proceeds to the right in the drawing in a state where the second light is superimposed on the first light. Then, both of these lights enter the half-wave plate 236 as in the case of the first embodiment, and
It reaches 91.

As described above, the measurement light emitted from the light source 211 is split into the first light as the transmitted light and the second light as the reflected light by the polarization beam splitter 221, and then the test light is superposed. Although guided to the object 291, the first light passes through the semi-permeable film of the polarization beam splitter 221 as it is, and is normally reflected by the reflection mirror 242, and is further normally reflected by the semi-permeable film of the polarization beam splitter 221. On the other hand, the second light is subjected to a special reflection such that the incident light path and the reflected light path become parallel (reflects light in the incident direction) due to the above-described positional relationship between the lens 232 and the reflection mirror 233, and then the half of the deflection beam splitter 221. Because it passes through the permeable membrane,
When these first and second light beams are superimposed and emitted from the deflection beam splitter 221 to the right in the drawing, the first and second light beams are shifted in the emission direction shift of the measurement light beam due to the unstable posture of the light source 211. One light has the same amount of shift in the same direction as the measurement light emission direction shift, and the second light has the same amount of shift in the direction opposite to the first light. For this reason, the same effect as that of the first embodiment can be obtained.

FIG. 11 shows a fourth embodiment of the eccentricity measuring apparatus according to the third invention. In this embodiment, a corner cube 240 is provided in place of the configuration of the third embodiment (FIG. 10) including the lens 232 and the reflection mirror 233. Also in this configuration, 1
The second light that has passed through the 板 wavelength plate 231 from right to left passes through the 板 wavelength plate 231 from left to right on the same path, and therefore has the same effect as that of the third embodiment ( That is, the same effect as in the first embodiment can be obtained.

FIG. 12 shows a fifth embodiment of the eccentricity measuring apparatus according to the first invention. In this embodiment, the polarization beam splitter 221 in the above-described third embodiment (FIG. 10) is rearranged such that the direction in which reflected light of light from the light source 211 exits to the right in the drawing.

In such a configuration, first, the light from the light source 211 in the polarizing beam splitter 21 is first light that is P-polarized light transmitted through the semi-permeable film and second light that is S-polarized light reflected by the semi-permeable film. And divided into Then, the first light transmits through the quarter-wave plate 241, is reflected by the reflection mirror 242, passes through the quarter-wave plate 241 again, and enters the polarization beam splitter 221 from below in the figure. Here, the first light was P-polarized light when transmitted through the polarization beam splitter 221, but was reflected by the reflection mirror 242 to return to the polarization beam splitter 221 before the 光 wavelength plate 241. Since it has passed twice,
When the light enters the polarization beam splitter 221 from below, it is S-polarized. Therefore, the first light is reflected by the semi-permeable film of the polarizing beam splitter 221 and proceeds to the left in the drawing.

The first light further passes through the quarter-wave plate 231 and is condensed by the lens 232, and is reflected by the reflection mirror 233 located at the condensing point. Then, the light again passes through the lens 232 and the quarter-wave plate 231 and enters the polarization beam splitter 221 from the left side in the drawing. Here, the first light was s-polarized light at the time when it was reflected to the left by the polarization beam splitter 221, but it was 1/4 before being reflected by the reflection mirror 233 and returning to the polarization beam splitter 221 again. Since the light passes through the wave plate 231 twice, the light is P-polarized when the light enters the polarization beam splitter 221 from the left. Therefore, the first light passes through the polarization beam splitter 221 from left to right as it is. On the other hand, the polarization beam splitter 22
In FIG. 1, the second light reflected to the right travels to the right in the figure while being superimposed on the first light. Then, both of these lights enter the half-wave plate 236 as in the case of the first embodiment, and reach the test object 291.

As described above, the measurement light emitted from the light source 211 is split by the polarizing beam splitter 221 into the first light as the transmitted light and the second light as the reflected light, and the test light is superposed. Although guided to the object 291, the second light normally reflects on the semi-permeable film of the polarizing beam splitter 221, whereas the first light normally reflects on the reflecting mirror 242, and furthermore, the semi-permeable film of the polarizing beam splitter 221. After performing normal reflection at the lens 232 and the reflection mirror 2
Since the incident light path and the reflected light path become parallel (reflect light in the incident direction) due to the above-mentioned positional relationship with the light beam 33 and then pass through the semi-permeable membrane of the deflecting beam splitter 221, When the first light and the second light are superimposed and emitted from the deflection beam splitter 221 to the right in the drawing, the first light and the second light are compensated for the deviation of the measurement light emission direction caused by the unstable posture of the light source 211. Causes the same amount of shift in the same direction as the shift of the measurement light emission direction.
The light will shift the same amount in the opposite direction to the first light. Therefore, the same effect as that of the third embodiment (that is, the same effect as that of the first embodiment) can be obtained.

FIG. 13 shows a sixth embodiment of the eccentricity measuring apparatus according to the third invention. In this embodiment, the corner cube 2 is replaced with the configuration including the lens 232 and the reflection mirror 233 in the fifth embodiment (FIG. 12).
40 are installed. Also in this configuration, 1 /
The second light transmitted through the four-wavelength plate 231 from right to left passes through the quarter-wavelength plate 231 from left to right along the same path. The same effect as in the case of the first embodiment can be obtained.

FIG. 14 shows a seventh embodiment of the eccentricity measuring apparatus according to the third invention. In this embodiment, the polarization beam splitter 221 in the above-described first embodiment (FIG. 7) is rearranged so that the emission direction of the reflected light is on the right side in the drawing, and the configuration including the lens 232 and the reflection mirror 233 is adopted. Is replaced with a right-angle prism 243, and the reflection mirror 235 is replaced with a right-angle prism 244. Here, both right-angle prisms 243, 244
As shown in the figure, are provided such that the planes including the incident light and the reflected light are orthogonal to each other.

In such a configuration, the measurement light from the light source 211 is firstly subjected to the polarization beam splitter 221 by the first light which is P-polarized light transmitted through the semi-permeable film and the second light which is S-polarized light reflected by the semi-permeable film. Split into light and Here, the first light passes through the polarizing beam splitter 221 as it is in the lower part of the figure, but the second light is reflected to the right in the figure, passes through the quarter-wave plate 234, and is reflected by the right-angle prism 244. . Then, the light again passes through the quarter-wave plate 234 and enters the polarization beam splitter 221 from the right. Here, the second light was s-polarized light when reflected by the polarization beam splitter 221, but was reflected by the right-angle prism 244 and returned to the polarization beam splitter 221 again. Since it has passed twice, it is P-polarized when it enters the polarization beam splitter 221 from the right. For this reason, the second light passes through the polarizing beam splitter 221 as it is from right to left, and further passes through the quarter-wave plate 231 to pass through the right-angle prism 2.
It reaches 43. Then, after being reflected by the right-angle prism 243, it is transmitted again through the 板 wavelength plate 231 and enters the polarization beam splitter 221 from the left.

Here, the second light is the polarized beam splitter 2
21 was P-polarized light when it was transmitted from the right to the left.
31 has passed through the polarization beam splitter 2 twice.
21 is S-polarized when it is incident from the left.
Therefore, the second light is reflected by the semi-permeable film of the polarization beam splitter 221 and travels straight downward in the figure while being superimposed on the first light. Then, both of these lights enter the half-wave plate 236 as in the case of the first embodiment, and reach the test object 291.

As described above, the measuring light emitted from the light source 211 is split into the first light, which is transmitted light, and the second light, which is reflected light by the polarizing beam splitter 221, and then the test light is superposed. It is led to the surface to be inspected of the object 291,
The first light is transmitted through the semi-permeable membrane of the polarizing beam splitter 221 and proceeds straight, while the second light is transmitted through the right-angle prism 2.
After normal reflection at 44, normal reflection at the semi-permeable membrane of the polarizing beam splitter 221,
3, the incident light path and the reflected light path become specially parallel (reflect light in the incident direction) and then normally reflected by the semi-permeable film of the polarizing beam splitter 221. On the other hand, the first light has the same amount of shift in the same direction as the emission direction of the measurement light, and the second light has the same amount of shift in the direction opposite to the first light. For this reason, the same effect as that of the first embodiment can be obtained.

FIG. 15 shows an eighth embodiment of the eccentricity measuring apparatus according to the third invention. In this embodiment, the し た wavelength plate 234 and the right-angle prism 244 provided on the right side of the polarization beam splitter 221 in the seventh embodiment (FIG. 14) are removed, and the light emitted therefrom is reduced by one.
A 波長 wavelength plate 245 and a right-angle prism 246 are provided below the polarization beam splitter 221 (corresponding to the left side in FIG. 15) while being guided to the 波長 wavelength plate 326. Here, the double right-angle prism 24 is also used.
3, 246 are provided in such a posture that planes including incident light and reflected light are orthogonal to each other.

In such a configuration, the measurement light from the light source 211 traveling from the right side in FIG. 15 is first supplied to the polarizing beam splitter 221 by the first light as P-polarized light transmitted through the semi-permeable film and the semi-permeable film. And the second light that is S-polarized light reflected at The first light passes through the quarter-wave plate 245, is reflected by the right-angle prism 246, and is again quarter-wave.
The light passes through the wave plate 245 and enters the polarization beam splitter 221 from the left side in the drawing. Here, the first light was P-polarized light when transmitted through the semi-permeable membrane of the polarization beam splitter 221, but was reflected by the right-angle prism 246 and returned to the polarization beam splitter 221 again by 1/4.
Since the light passes through the wave plate 245 twice, when the light enters the polarization beam splitter 221 from the left side in the drawing, the light is S-polarized. For this reason, the first light is polarized beam splitter 2
The light is reflected at the semipermeable membrane 21 and proceeds downward in the figure.

On the other hand, the second light is reflected upward in FIG.
After passing through the wave plate 231, the light is reflected by the right-angle prism 243. Then, the light again passes through the quarter-wave plate 231 and enters the polarization beam splitter 221 from above in the drawing. Here, the second light was s-polarized light when reflected by the polarization beam splitter 221, but was reflected by the right-angle prism 243 and again returned to the polarization beam splitter 22.
Since the light passes through the quarter-wave plate 231 twice before returning to 1, the light is P-polarized when it enters the polarization beam splitter 221 from above in the drawing. Therefore, the second light passes through the semi-permeable film of the polarizing beam splitter 221 as it is, and goes straight down in the figure in a state where the second light is overlapped with the first light. Then, both of these lights enter the half-wave plate 236 as in the case of the above-described seventh embodiment (that is, as in the case of the first embodiment), and reach the test object 291.

As described above, the measuring light emitted from the light source 211 is split by the polarizing beam splitter 221 into the first light as the transmitted light and the second light as the reflected light, and the test light is superposed. It is led to the surface to be inspected of the object 291,
The first light undergoes special reflection in the right-angle prism 246 so that the incident light path and the reflected light path become parallel (reflects the light in the incident direction), and after being normally reflected by the semi-permeable film of the polarizing beam splitter 221, The second light is normally reflected by the prism 246 and then passes through the semi-permeable membrane of the polarizing beam splitter 221, whereas the second light is normally reflected by the right-angle prism 243 and then passes through the semi-permeable membrane of the polarizing beam splitter 221. Therefore, the first light has the same amount of shift in the same direction as the measurement light emission direction shift with respect to the measurement light emission direction shift, and the second light has the same amount shift in the direction opposite to the first light. Will occur. Therefore, the same effect as that of the above-described seventh embodiment (that is, the case of the first embodiment) can be obtained.

FIG. 16 shows a ninth embodiment of the eccentricity measuring apparatus according to the third invention. In this embodiment, the polarization beam splitter 221 in the eighth embodiment (FIG. 15) is rearranged so that the direction of emission of the reflected light of the light from the light source 211 is below the figure.

In such a configuration, the measurement light from the light source 211 traveling from the right side of FIG. And the second light that is S-polarized light reflected at The first light passes through the quarter-wave plate 245, is reflected by the right-angle prism 246, and is again quarter-wave.
The light passes through the wave plate 245 and enters the polarization beam splitter 221 from the left side in the drawing. Here, the first light was P-polarized light when transmitted from the right to the left through the polarization beam splitter 221, but was reflected by the right-angle prism 246 before returning to the polarization beam splitter 221 again. Since the light beam has passed through the 波長 wavelength plate 245 twice, when the light beam enters the polarization beam splitter 221 from the left side in the drawing, S
It is polarized. Therefore, the first light is reflected by the semi-permeable film of the polarizing beam splitter 221 and proceeds upward in the drawing.

The first light traveling upward in the figure further passes through the quarter-wave plate 231, is reflected by the right-angle prism 243, passes again through the quarter-wave plate 231, and is reflected by the polarization beam splitter 221. From above. Here, the first light was s-polarized at the time when the first light was reflected upward by the polarization beam splitter 221, but the right-angle prism 243 was used.
Since the light beam passes through the quarter-wave plate 231 twice before being reflected at and returning to the polarization beam splitter 221 again, when the light enters the polarization beam splitter 221 from above, it becomes P-polarized light. Therefore, the first light passes through the polarizing beam splitter 221 as it is in the lower part of the figure. On the other hand, the second light reflected on the semi-permeable film of the polarization beam splitter 221 proceeds downward in the figure while being superimposed on the first light. And both of these lights are the first
Incident on the half-wave plate 236 as in the case of the embodiment,
The object 291 is reached.

As described above, the measuring light emitted from the light source 211 is split by the polarizing beam splitter 221 into the first light as the transmitted light and the second light as the reflected light, and the test light is superposed. It is led to the surface to be inspected of the object 291,
After the first light has a special reflection in the right-angle prism 246 where the incident light path and the reflected light path are parallel (reflects the light in the incident direction) and is normally reflected on the semi-permeable film of the polarizing beam splitter 221, the right-angle prism At 243, the light is normally reflected and then transmitted through the semipermeable membrane of the polarization beam splitter 221, whereas the second light is reflected by the polarization beam splitter 221.
Since the light is normally reflected by the semi-permeable film of the first type, the first light has the same amount of shift in the same direction as the shift of the measurement light in the emission direction with respect to the shift of the measurement light in the emission direction, and the second light has the first light. The same amount of shift occurs in the opposite direction. Therefore, the same effect as that of the above-described seventh embodiment (that is, the case of the first embodiment) can be obtained.

FIG. 17 shows a tenth embodiment of the eccentricity measuring apparatus according to the third aspect of the present invention, and the above-described first embodiment (FIG. 7).
One polarization beam splitter 221 and two 1
波長 wavelength plates 231, 234, one lens 232 and 2
The configuration including the two reflection mirrors 233 and 235 is replaced by two beam splitters 247 and 248 and two reflection mirrors 2.
49, 250 and two lenses 251, 252. Here, the beam splitter 2
47 and 248 and the reflection mirrors 249 and 250 are installed in parallel with each other.

In such a configuration, the light from the light source 211 traveling from the left in FIG.
At 47, the light is split into a first light that transmits through the semi-permeable film and a second light that is reflected by the semi-permeable film. Beam splitter 2
The first light that has passed through 47 is reflected at the reflection mirror 249 downward in the figure, and further reflected at the beam splitter 248 to the right in the figure. On the other hand, the second light reflected by the beam splitter 247 and traveling downward in the figure is reflected rightward in the figure by the reflection mirror 250, and once condensed by the lens 251, and has the same focal length as the lens 251. After being made into parallel light again by the lens 252 whose focus is set at the same position as the focal position of the lens 251, the light is transmitted through the beam splitter 248 from left to right. Then, both of these lights enter the half-wave plate 236 as in the first embodiment, and reach the test object 291.

As described above, the measurement light emitted from the light source 211 is split by the beam splitter 247 into the first light, which is transmitted light, and the second light, which is reflected light. Although the first light is guided to the surface to be inspected at 291, the first light normally reflects at the reflecting mirror 249 and then further reflects at the beam splitter 248,
After the second light is normally reflected by the reflection mirror 250,
The light travels straight through the two lenses 251 and 252 (at this time, if there is a shift in the emission direction of the measurement light, the shift direction of the second light is reversed). One light has the same amount of shift in the same direction as the measurement light emission direction shift, and the second light has the same amount of shift in the direction opposite to the first light. For this reason, the same effect as that of the first embodiment can be obtained.

FIG. 18 shows an eleventh embodiment of the eccentricity measuring apparatus according to the third aspect of the present invention.
7) Two beam splitters 247, 248
Is replaced by two polarizing beam splitters 253 and 254 installed such that the semipermeable membranes are parallel to each other.

In such a configuration, the light from the light source 211 traveling from above in FIG. 18 is first polarized by the polarizing beam splitter 253 to be the first P-polarized light transmitted through the semi-permeable film.
The light is split into light and second light, which is S-polarized light reflected by the semi-permeable film. The first light that has passed through the semi-permeable membrane of the polarizing beam splitter 253 and has traveled downward in the figure is reflected rightward in the figure by the reflection mirror 250, is once collected by the lens 251, and then focuses on the lens 251. The distance is the same,
After being converted into parallel light again by the lens 252 whose focal point is set to the same position as the focal position of the lens 251, the light passes through the semi-permeable membrane of the polarizing beam splitter 254 from left to right. On the other hand, the second light reflected rightward in the figure at the semi-permeable film of the polarization beam splitter 253 is reflected by the reflection mirror 249.
At the bottom of the figure, and further to the right of the figure at the semi-permeable membrane of the polarizing beam splitter 254. And
Both of these lights enter the half-wave plate 236 as in the first embodiment, and reach the test object 291.

As described above, the measurement light emitted from the light source 211 is split into the first light, which is transmitted light, and the second light, which is reflected light by the polarizing beam splitter 253, and the test light is superposed. It is led to the surface to be inspected of the object 291,
After the first light normally reflects on the reflection mirror 250,
While the light goes straight through the two lenses 251 and 252 (at this time, if there is a shift in the emission direction of the measurement light, the shift direction of the second light is reversed), whereas the second light is reflected by the reflection mirror 24.
9, after the normal reflection, the polarization beam splitter 2
Since the light is normally reflected by the semi-permeable film 54, the first light has the same amount of displacement in the same direction as the displacement of the measurement light in the emission direction with respect to the displacement of the measurement light in the emission direction.
The same amount of shift occurs in the direction opposite to the light. Therefore, it is possible to obtain exactly the same effects as in the case of the above-described first embodiment.

FIG. 19 shows a twelfth embodiment of the eccentricity measuring apparatus according to the third invention. The eccentricity measuring apparatus according to this embodiment is an example of a case where the transmission eccentricity of the test object 292 which is a convex lens is measured. This device has the basic configuration shown in the first embodiment described above. However, after removing the half-wave plate 236 provided in the first embodiment, the device is located below the test object 292 (in FIG. Lens 2 at the bottom)
53 is different. In such a configuration,
When measuring the transmission eccentricity of the test object 292 which is a convex lens, the polarization beam splitter 22
The first and second lights, which are emitted downward in the figure, are focused by the focus lens system 260 at a position near the front focus of the test object 292 (convex lens).

As a result, the first light transmitted through the test object 292
The second light and the second light are collimated and converged on the reflection mirror 34, and are respectively measured on the measurement surface (the light receiving surface of the light position detecting element 270).
Although an optical spot is formed on the upper side, when the test object 91 is not eccentric, the optical axis (transmitted optical axis) when both the first and second lights pass through the test object 292 is Both the light axes coincide with the optical axis (incident optical axis) when the light enters the test object 292, and the light quantity centroid positions of the light spots formed independently on the measurement surface by the first and second lights are both reference positions. (For this reason, the center of gravity of the total light amount of both light spots also matches the reference position). However, when the test object 92 is eccentric, the transmitted optical axis does not coincide with the incident optical axis (causes an angular deviation), so that both the first and second light beams are individually present on the measurement surface. Both the light quantity centroid positions of the light spots to be formed are shifted from the reference position (for this reason, the first and second light spots are shifted).
The position of the center of gravity of the total light amount of both lights is shifted from the reference position.)

Also in this configuration, the first light is displaced by the same amount in the same direction as the displacement of the measurement light due to the displacement of the measurement light due to the unstable orientation of the light source 211. And the second light is shifted by the same amount in the direction opposite to the first light, so that the same effect as in the first embodiment can be obtained. In addition, the 2nd above
The partial modification shown in the eleventh embodiment can be applied to the twelfth embodiment as it is.

As described above, in the eccentricity measuring apparatus and the eccentricity measuring method according to the third procedure of the present invention, the light source 2
After dividing the measurement light emitted from 11 into a first light and a second light, these two lights are condensed on a predetermined incident optical axis of the test object by the focus lens system 260 in a state of being superimposed, and The two lights reflected on or transmitted through the test object surface are guided on the same measurement surface to form light spots for both lights, and the deviation of the center of gravity of the total light quantity of both light spots from the reference position The eccentricity of the test object is calculated based on the amount. Here, the first light and the second light are adjusted so that the light amounts of both light beams are substantially equal at the time of division, and the first light is emitted in the emission direction of the measurement light with respect to the shift in the emission direction of the measurement light. Since the same amount of shift occurs in the same direction as the shift, and the second light is guided to the subject in such a manner as to cause the same amount of shift in the direction opposite to the first light. The eccentricity of the test object obtained based on the shift amount of the center of gravity of the total light quantity of both light spots from the reference position is a value in which the angular shift of both lights caused by the shift of the measurement light emission direction is offset. Becomes Therefore, even when the orientation of the light source 211 is unstable and the emission direction of the measurement light is shifted, this does not affect the measurement result, and the eccentricity measurement of the test object can be performed with high accuracy. Becomes

Also, here, only the case where the reflection eccentricity of the test object which is a concave lens is measured and the case where the transmission eccentricity of the test object which is a convex lens is measured are shown. By appropriately rearranging the configuration of the system,
It is possible to measure the transmission eccentricity of the test object which is a concave lens and to measure the reflection eccentricity of the test object which is a convex lens.

Next, an eccentricity measuring apparatus and an eccentricity measuring method according to the fourth invention will be described. FIG. 20 shows an embodiment of the eccentricity measuring apparatus according to the fourth aspect of the present invention, and is an example in the case of measuring the transmission eccentricity of a test object 391 which is a convex lens. In this eccentricity measuring device, the light source 3
The measurement light emitted from 11 is condensed by a lens 312 and enters a collimator lens 314 via an index 313 located at the condensing point. The measurement light converted into parallel light by the collimator lens 314 is applied to the polarization beam splitter 32.
1 and is split into a first light, which is a P-polarized light transmitted through the semi-permeable film, and a second light, which is an S-polarized light reflected by the semi-permeable film. Here, as in the eccentricity measuring apparatuses according to the first and third aspects of the present invention, the light amounts of the first and second lights are made substantially equal (the light amount difference between the two lights is extremely small). It is not necessary to keep it. The reason for this is the same as in the case of the eccentricity measuring device according to the second aspect of the present invention described above, and the center of gravity of the light amount of the first light spot (first light spot) and the second light spot (second light spot). This is because the center of gravity of the light amount is calculated separately, and the position of the center of gravity does not depend on the light amount balance of the first light and the second light.

The first light transmitted through the semi-permeable film of the polarizing beam splitter 321 proceeds as is in the lower part of the figure, while the second light reflected by the semi-permeable film of the polarizing beam splitter 321 proceeds to the left in the figure to be 1 / After passing through the four-wavelength plate 331, the light is condensed by the lens 332 and reflected by the reflection mirror 333 located at the condensing point. And the lens 33 again
The light passes through the 2 and １ ／ wavelength plates 331 and enters the polarization beam splitter 321 from the left side in the figure.

Here, the second light is the polarized beam splitter 3
At the time when the light was reflected to the left by the semi-permeable film of No. 21, the light was S-polarized light.
Since the light passes through the four-wavelength plate 331 twice, it is P-polarized light when it enters the polarization beam splitter 321 from the left. For this reason, the second light passes through the polarization beam splitter 321 to the right as it is, and
After passing through the 波長 wavelength plate 334 provided to the right of FIG. 1 (to the right in the drawing), the light is reflected by the reflection mirror 335. Then, the light again passes through the quarter-wave plate 334 and enters the polarization beam splitter 321 from the right side in the drawing.

Here, the second light is the polarized beam splitter 3
At the time when the semipermeable membrane No. 21 penetrated from the left to the right in the figure, P
Although the light is polarized, it passes through the quarter-wave plate 334 twice before being reflected by the reflection mirror 335 and returning to the polarization beam splitter 321 again. When the light is incident from one side, it is S-polarized. For this reason, the second light is reflected by the semi-permeable film of the polarizing beam splitter 321 and proceeds downward in the figure while being superimposed on the first light.

The first and second beams emitted below the polarizing beam splitter 321 in the state of being superposed in this way
Both lights are condensed at a position near the front focus of the test object 391 by a focus lens system 360 including a movable lens 361 formed of a biconvex lens and a fixed lens 362 formed of a biconcave lens. Index 31 on the surface
Three images are projected.

The two lights condensed at a position near the front focal point of the test object 391 pass through the test object 391, become parallel light, and enter the polarization beam splitter 336 from above in the figure. Here, the first light, which is P-polarized light, is supplied to the polarization beam splitter 3.
The light passes through the semipermeable membrane of No. 36 and proceeds downward in the figure, and the lens
To the first measurement surface (the first light position detecting element 371).
A first light spot is formed on the light receiving surface of the first light spot. The second light, which is the S-polarized light, is reflected by the semi-permeable film of the polarization beam splitter 336, travels to the right in the drawing, is collected by the lens 338, and is focused on the second measurement surface (the second light position detection element 372). A second light spot is formed on the light receiving surface).

As described above, the measurement light emitted from the light source 311 is split by the polarizing beam splitter 321 into the first light, which is transmitted light, and the second light, which is reflected light. It is led to the surface to be inspected of the object 391,
While the first light passes through the semi-permeable membrane of the polarizing beam splitter 321 as it is, the incident light path and the reflected light path of the second light become parallel due to the above-described positional relationship between the lens 332 and the reflection mirror 333 (light is incident on the reflection light path). After the special reflection (reflecting in the direction), the light is transmitted through the semi-permeable film of the polarization beam splitter 321, and is further normally reflected by the reflection mirror 335, and then is normally reflected by the semi-permeable film of the polarization beam splitter 321. When the first light and the second light are superimposed and emitted downward from the deflection beam splitter 321, the first light and the second light are offset by the deviation of the measurement light emission direction due to the unstable posture of the light source 311. Causes the same amount of shift in the same direction as the measurement light emission direction shift, and the second light causes the same amount of shift in the opposite direction to the first light (see FIG. 8).

The first light position detecting element 371 detects the position of the center of the light quantity of the first light spot formed on the light receiving surface (first measurement surface), and outputs the result to the eccentricity calculator 380. Further, the second light position detecting element 372 has a light receiving surface (second
Of the second light spot formed on the (measurement surface) is detected, and the result is output to the eccentricity calculator 380 in the same manner. The eccentricity calculator 380 is used for the first light position detecting element 3
The light quantity centroid of the second light spot detected by the second light position detecting element 372 from the shift angle of the first light obtained based on the displacement amount of the light quantity centroid position of the first light spot detected by 71 from the reference position. The eccentricity of the test object 391 is calculated by subtracting the shift angle of the second light obtained based on the shift amount of the position from the reference position, and this is displayed on a display or the like.

Here, the reference position is the first light which is formed on the first measurement surface by the first light reflected on the surface of the test object 391 when the test object 391 has no eccentricity. The light intensity barycentric position of the spot and the light intensity barycentric position of the second light spot formed on the second measurement surface by the second light. When the test object 391 is not eccentric, the first and second lights are emitted from the test object 3.
The optical axis (incident optical axis) when entering the object 91 and the test object 391
Are transmitted, the optical axis (transmitted optical axis) coincides, the first light spot formed on the first measurement surface by the first light has the light quantity centroid position coincident with the reference position, and the second light has the second light spot. Of the second light spot formed on the measurement surface of the second light spot also coincides with the reference position. However, when the test object 391 is eccentric, its transmitted optical axis does not coincide with the incident optical axis (causes an angular deviation), so that the positions of the light spots formed on the respective measurement surfaces by both lights are different. Are each shifted from the reference position.

Further, the posture of the light source 311 is unstable,
The emission direction of the measurement light is the reference direction (here, the test object 391).
Deviated from the predetermined incident optical axis direction), the reflected optical axes of the first and second lights on the test object 391 coincide with the incident optical axis regardless of the eccentricity of the test object 391. Therefore, the position of the first light spot formed on the first measurement surface by the first light transmitted through the test object 391 is shifted from the reference position, and the second light is formed on the second measurement surface. The second to form
The position of the light spot also deviates from the reference position.

Here, as described above, the first light and the second light have the same amount of displacement in the same direction as the displacement of the measurement light with respect to the displacement of the measurement light with respect to the displacement of the measurement light. , The second light is guided so as to generate the same amount of shift in the direction opposite to the first light, so that the shift of the light quantity centroid position of the first light spot formed on the first measurement surface from the reference position Quantity and the second
The amount of deviation of the center of gravity of the light amount of the second light spot formed on the measurement surface from the reference position is the same as the deviation of the measurement light in the emission direction. For this reason, based on the shift amount of the light quantity centroid position of the first light spot formed on the first measurement surface from the reference position and the shift quantity of the light quantity centroid position of the second light spot from the reference position (the second light spot). From the shift angle of the first light obtained based on the shift amount of the light quantity centroid position of one light spot from the reference position, the second light obtained based on the shift amount of the light quantity centroid position of the second light spot from the reference position. The eccentricity of the test object obtained by subtracting the shift angle is a value in which the angle shift between the two light beams caused by the shift in the emission direction of the measurement light is offset, and the posture of the light source 311 is unstable and the measurement light This does not affect the measurement result even if the emission direction of the laser beam is shifted.

However, also in this case, similarly to the eccentricity measuring apparatus according to the first to third aspects of the present invention, the focus lens system 360 uses the means (here, the deflection beam splitter 321) for dividing the measuring light. It is installed on the downstream side, and the focus lens system 360 has an optical axis shift (movable lens 3
61 does not coincide with the optical axis of the fixed lens 362), the test object 391 is placed in the first position regardless of the eccentricity.
Since the optical axis of the light reflected by the test object 191 does not coincide with the incident optical axis, the first light reflected by the test surface of the test object 391 is the first light.
The positions of the light spots formed by the second light and the second light on the respective measurement surfaces are respectively shifted from the reference positions. Therefore, when performing eccentricity measurement of the test object 391 using this apparatus, the turntable (not shown) holding the test object 391 is rotated to rotate the test object 391 around the optical axis. Accordingly, the position of the center of gravity of the light amount of the first light spot (or the second
It is necessary to observe whether the light spot center of gravity of the light spot fluctuates (rotates around the reference position). Here, when the position of the light quantity center of gravity of the first light spot (or the position of the light quantity center of gravity of the second light spot) does not fluctuate with the rotation of the test object 391, the deviation from the reference position is equal to the test object 3.
The focus lens system 3 is not due to the eccentricity of 91.
This is due to 60 optical axis shifts.

As described above, in the eccentricity measuring apparatus and the eccentricity measuring method according to the fourth procedure of the present invention, the light source 3
After dividing the measurement light emitted from 11 into a first light and a second light, these two lights are condensed on a predetermined incident optical axis of the test object by the focus lens system 360 in a state of being superimposed, and Of the two lights transmitted through the specimen (or reflected on the surface to be inspected), the first light is guided on the first measurement surface to form a light spot, and the second light is transmitted to the second measurement surface. The light spot is formed by guiding the light spot upward, and the eccentricity of the test object is calculated based on the shift amount of the first light spot from the reference position and the shift amount of the second light spot from the reference position. Here, since the first and second lights reach the test object in such a state that the same amount of angle shift occurs with respect to the shift of the measurement light emission direction, the first light spot The eccentricity of the test object obtained based on the shift amount of the light quantity centroid position from the reference position and the shift quantity of the second light spot from the reference position of the light quantity centroid is caused by the displacement of the measurement light in the emission direction. The resulting angular deviation between the two lights is a value that is offset. For this reason, even when the orientation of the light source 311 is unstable and the emission direction of the measurement light shifts, this does not affect the measurement result, and the eccentricity measurement of the test object can be performed with high accuracy. Becomes

Also, here, only the case where the transmission eccentricity of the test object which is a convex lens is measured has been described.
It is possible to measure the reflection eccentricity of the test object which is a convex lens and the transmission eccentricity and the reflection eccentricity of the test object which is a concave lens. Note that, in the above embodiment, the first and second split light beams have the same amount of displacement in the same direction as the measurement light emission direction shift with respect to the measurement light emission direction shift, and the measurement light emission direction shift. The second light is guided so as to generate the same amount of displacement in the direction opposite to the first light, but both lights are guided so as to produce the same amount of angular displacement with respect to the displacement of the measurement light in the emission direction. , It is not always necessary to shift in the opposite directions.

Next, an eccentricity measuring apparatus and an eccentricity measuring method according to the fifth invention will be described. FIG. 21 shows the first embodiment of the eccentricity measuring apparatus according to the fifth aspect of the present invention, and is an example in the case of measuring the reflection eccentricity of a test object 491 which is a convex lens. In this eccentricity measuring device, the measurement light emitted from the light source 411 is condensed by the lens 412 and enters the collimator lens 414 via the index 413 located at the condensing point.

The measurement light converted into parallel light by the collimator lens 414 passes through a focus lens system 460 including a movable lens 461 formed of a biconvex lens and a fixed lens 462 formed of a biconcave lens, and is incident on a polarization beam splitter 421. Then, the polarization beam splitter 42
The measurement light incident on 1 is split into first light, which is P-polarized light transmitted through the semi-permeable film, and second light, which is S-polarized light reflected on the semi-permeable film. Here, the state of the light incident on the polarization beam splitter 421 is adjusted so that the light amounts of the first light and the second light are substantially equal (so that the light amount difference between the two lights is extremely small). deep. The reason is that the light spot of the first light and the second light spot formed on the same measurement surface are the same as in the case of the eccentricity measuring apparatus according to the first or third aspect of the present invention.
This is because the center of gravity of the total light amount is calculated from the light spot of the light, and if the light amount of each light is different, the position of the center of gravity shifts.

The first light that has passed through the semi-permeable film of the polarizing beam splitter 421 proceeds rightward in the figure as it is, passes through the quarter-wave plate 423, and passes through the first reflecting surface 4 of the corner mirror 424.
24a. The first incident on the first reflecting surface 424a
The light is reflected downward in the figure and is incident on the second reflecting surface 424b of the corner mirror 424, where it is further reflected to the left in the figure, then passes through the quarter-wave plate 425, and is transmitted to the polarizing beam splitter 426. Light enters from the right side of the figure. Here, the first light was P-polarized light at the time when it passed through the semi-permeable film of the polarizing beam splitter 421, but before reflected by the corner mirror 424 and incident on the polarizing beam splitter 426, two 1/1 light beams were used. Since the light passes through the four-wavelength plates 423 and 425, the light is s-polarized when it enters the polarization beam splitter 426 from the right. Therefore, the first light is reflected by the semi-permeable membrane of the polarizing beam splitter 426,
Go to the bottom of the figure.

On the other hand, the second light reflected on the semi-permeable film of the polarizing beam splitter 421 and traveling upward in the figure is transmitted through the quarter-wave plate 427 and then reflected on the reflection mirror 428. Then, the light again passes through the quarter-wave plate 427 and enters the polarization beam splitter 421 from above in the drawing. Here, the second light was S-polarized light at the time when the second light was reflected upward in the drawing at the semipermeable membrane of the polarizing beam splitter 421,
The １ ／ wavelength plate 4 is used before the light is reflected by the reflection mirror 428 and returns to the polarization beam splitter 421 again.
27, the polarization beam splitter 4
21 is P-polarized when it is incident from above in the figure. Therefore, the second light passes through the semi-permeable membrane of the polarizing beam splitter 421, and further passes through the semi-permeable membrane of the polarizing beam splitter 426. The corner mirror 424 has an appropriate position and posture such that the optical path lengths of the measurement light are equal to each other between the time when the measurement light is separated into the first light and the second light and the time when the two lights are overlapped again. Placed in

The first and second beams emitted below the polarizing beam splitter 426 in the state of being superposed in this manner are superposed.
The two lights pass through a quarter-wave plate 429 installed below (below in the figure) the polarizing beam splitter 426, and then enter the polarizing beam splitter 430. here,
Since both the first and second lights pass through the quarter-wave plate 429 and are both circularly polarized, the respective P-polarized light components pass through the semi-permeable membrane of the polarizing beam splitter 430, and are further reduced by a quarter.
The light passes through the wave plate 431 and is incident on the surface of the test object 491. Here, the position of the movable lens 461 of the focus lens system 460 is adjusted such that both the first and second lights are focused on the focal position of the test object 491. Thus, an image of the index 413 is formed on the surface of the test object 491.

The first light focused at the focal position of the test object 491
The second light and the second light are reflected on the surface to be inspected of the object 491, become parallel light, again pass through the quarter-wave plate 431, and enter the polarization beam splitter 430 from below in the figure. Here, the first light and the second light are polarized beam splitters 430.
At the time when the light was transmitted downward,
The １ ／ wavelength plate 43 is reflected by the surface to be inspected 91 and returns to the polarization beam splitter 430 again.
1 twice, the polarization beam splitter 43
When the light enters from 0 below, it is S-polarized light. Therefore, both the first and second lights are reflected by the semi-permeable film of the polarizing beam splitter 430 and travel to the right in the drawing. Then, the light is condensed by a lens 432 provided on the right side (the right side in the drawing) of the polarization beam splitter 430 to form a light spot on the same measurement surface (light receiving surface of the light position detecting element 470).

The measuring light emitted from the light source 411 is split by the polarizing beam splitter 421 into the first light, which is transmitted light, and the second light, which is reflected light. Although the first light is guided to the surface to be inspected at 491, the first light passes through the polarizing beam splitter 421 to the right, and then the incident light and the reflected light are parallelized by the corner mirror 424 (the light is reflected in the incident direction). A strong reflection,
Further, while the light is normally reflected on the semi-permeable membrane of the polarization beam splitter 426 to reach the test object 491, the second light reflected upward in the drawing by the polarization beam splitter 421 is:
After being normally reflected by the reflection mirror 428, the light passes through the semi-permeable films of the two polarization beam splitters 421 and 426 as it is and reaches the test object 491, so that the first light is measured with respect to the deviation of the measurement light emission direction. A shift of the same amount occurs in the same direction as the shift of the light emission direction, and the second light shifts by the same amount in the direction opposite to the first light (see FIG. 8).

The light position detecting element 470 detects the position of the center of gravity of the total light amount of these two light spots formed on the light receiving surface (measurement surface), and outputs the result to the eccentricity calculator 480. The eccentricity calculator 480 calculates the eccentricity of the test object 491 based on the amount of deviation between the detected center of gravity of the total light amount of both light spots and a predetermined reference position, and displays this on a display or the like. . Here, the reference position is the test object 49.
When there is no eccentricity in 1, the position of the center of gravity of the total light amount of both light spots is located on the measurement surface. Test object 491
Is not eccentric, the optical axis (reflected optical axis) when the first and second lights are reflected on the surface of the test object 491 is the optical axis when the light enters the test object 491. (Incident optical axis)
And the center of gravity of the light amount of the light spot formed independently on the measurement surface by the first and second lights respectively coincides with the reference position (for this reason, the position of the center of gravity of the total light amount of both light spots also coincides with the reference position) However, when the test object 491 is eccentric, the reflected optical axis does not coincide with the incident optical axis (causes an angular deviation), so that the first and second lights are each independently measured on the measurement surface. Both the light quantity centroid positions of the light spots formed above deviate from the reference position (for this reason, the total light quantity centroid position of both the first and second lights deviates from the reference position).

Also, the attitude of the light source 411 is unstable,
The emission direction of the measurement light is the reference direction (here, the test object 491
(In the direction of the predetermined incident optical axis), the reflected light axis of the first light on the test object 491 does not coincide with the incident optical axis regardless of the eccentricity of the test object 491, so that Both the light quantity centroid position of the light spot formed by the first light and the second light reflected on the surface to be inspected of the inspection object 491 independently on the measurement surface are shifted from the reference position.

Here, as described above, the first and second light beams are adjusted so that the light amounts of the first and second light beams are substantially equal at the time of splitting by the polarizing beam splitter 421, and the first light beam and the second light beam are shifted with respect to the deviation of the measurement light emission direction. The first light has the same amount of shift in the same direction as the measurement light emission direction shift, and the second light has the same amount of shift in the direction opposite to the first light on the measurement surface. Therefore, the position of the center of gravity of the light spot of the first light formed on the measurement surface and the position of the center of light of the light spot of the second light are shifted in the opposite direction and by the same amount with respect to the shift in the emission direction of the measurement light. In addition, the light amounts of both light spots are equal. Therefore, the eccentricity of the test object 491 obtained based on the amount of deviation of the center of gravity of the total light amount of the two light spots formed on the measurement surface from the reference position is caused by the deviation of the measurement light emission direction. The resulting angle shifts of the two lights are offset values, and even if the orientation of the light source 411 is unstable and the emission direction of the measurement light shifts, this does not affect the measurement result.

In the eccentricity measuring apparatus according to the fifth aspect of the present invention, unlike the eccentricity measuring apparatuses according to the first to fourth aspects of the present invention, the focus lens system 460 transmits the measuring light. Since the splitting means (here, the deflection beam splitter 421) is installed on the upstream side, the focus lens system 460 has an optical axis shift (the optical axis of the movable lens 461 and the optical axis of the fixed lens 462 coincide with each other). No), the first and second lights are shifted in opposite directions and by the same amount of angle, so that the first and second lights formed on the measurement surface
The light spot of the light and the light spot of the second light are shifted by the same amount in the opposite direction to the shift of the emission direction of the measurement light.
For this reason, when the eccentricity measurement of the test object 491 is performed using this device, the test object 491 is moved to the same position as in the case of the above-described eccentricity measuring devices according to the first to fourth inventions. It is not necessary to rotate around the optical axis and check whether the detected eccentricity is due to the test object or to the optical axis shift of the focus lens system.

FIG. 22 shows a second embodiment of the eccentricity measuring apparatus according to the fifth invention. The eccentricity measuring apparatus according to this embodiment is an example of a case where the transmission eccentricity of a test object 492 which is a concave lens is measured. This device has the basic configuration shown in the above-described first embodiment (FIG. 21), and includes the deflection beam splitter 426 in the first embodiment and the quarter-wave plate 425 located on the right side (right side in the figure) of the deflection beam splitter 426. And the corner mirror 424 are removed, and a corner cube 433 is set to the right of the quarter-wave plate 423. In addition, the two quarter-wave plates 429 and 431, the deflection beam splitter 430, and the lens 432 are removed, and the test is performed. The lens 434 is provided below the object 492 (below in the figure).

In this eccentricity measuring device, the measuring light converted into parallel light by the collimator lens 414 passes through the focus lens system 460 and enters the polarizing beam splitter 421 from the left side in the figure. Then, the measurement light that has entered the polarization beam splitter 421 is split into a first light, which is P-polarized light transmitted through the semi-permeable film, and a second light, which is S-polarized light reflected on the semi-permeable film. Here, the state of the light incident on the polarization beam splitter 421 is adjusted so that the light amounts of the first light and the second light are substantially equal (so that the light amount difference between the two lights is extremely small). deep. The reason is the same as in the case of the above-described fifth embodiment of the present invention.

The first light that has passed through the semi-permeable film of the polarizing beam splitter 421 proceeds rightward in the figure as it is, passes through the quarter-wave plate 423, and is reflected by the corner cube 433. The first light reflected by the corner cube 433 again passes through the quarter-wave plate 423 and enters the polarization beam splitter 421 from the right side in the drawing. Here, the first light was P-polarized light when it passed through the semi-permeable membrane of the polarizing beam splitter 421 to the right in the drawing, but the corner cube 4
The light is reflected at 33 and is again reflected by the polarization beam splitter 421.
Since the light beam has passed through the quarter-wave plate 423 twice before returning to, the light is s-polarized when it enters the polarization beam splitter 421 from the right. Therefore, the first
Light is reflected by the semi-permeable membrane of the polarizing beam splitter 421, and travels downward in the figure.

On the other hand, the second light reflected on the semi-permeable film of the polarizing beam splitter 421 and traveling upward in the drawing is transmitted through the quarter-wave plate 427 and then reflected on the reflection mirror 428. Then, the light again passes through the quarter-wave plate 427 and enters the polarization beam splitter 421 from above in the drawing. Here, the second light was S-polarized light at the time when the second light was reflected upward in the drawing at the semipermeable membrane of the polarizing beam splitter 421,
The １ ／ wavelength plate 4 is used before the light is reflected by the reflection mirror 428 and returns to the polarization beam splitter 421 again.
27, the polarization beam splitter 4
21 is P-polarized when it is incident from above in the figure. For this reason, the second light passes through the semi-permeable membrane of the polarizing beam splitter 421, and proceeds downward in the drawing in a state where the second light is superimposed on the first light.

The first light and the second light emitted below the polarizing beam splitter 421 in the state of being superposed in this way are
The light is incident on the surface of the test object 492 located below the polarization beam splitter 421 (below the drawing).
Here, the movable lens 4 of the focus lens system 460
The position of the first light 61 and the second light 61 is adjusted such that the first light and the second light are converged at a position near the front focus of the test object 492. As a result, an image of the index 413 is formed on the surface of the test object 492. The first and second lights condensed at a position near the front focal point of the test object 492 pass through the test object 492 to become parallel lights, are condensed by the lens 434, and are respectively condensed by the same measurement surface (light A light spot is formed on the light receiving surface of the position detecting element 470).

As described above, the measuring light emitted from the light source 411 is split into the first light as the transmitted light and the second light as the reflected light by the polarizing beam splitter 421, and the test light is superposed. It is led to the surface to be inspected of the object 492,
After the first light passes through the polarization beam splitter 421 to the right, the incident light path and the reflected light path become specially parallel (reflect the light in the incident direction) due to the property of the corner cube 433, and further, the polarized light beam is reflected. While the second light is normally reflected by the semi-permeable film of the splitter 421, the second light is normally reflected by the reflection mirror 428, and then passes through the semi-permeable film of the polarization beam splitter 421. On the other hand, the first light has the same amount of shift in the same direction as the measurement light emission direction shift, and the second light has the same amount of shift in the direction opposite to the first light (see FIG. 8). ). For this reason, the same effect as that of the first embodiment can be obtained.

As described above, in the eccentricity measuring apparatus and the eccentricity measuring method according to the fifth procedure of the present invention, the light source 4
After the measurement light emitted from the lens 11 and transmitted through the focus lens system 460 is divided into a first light and a second light, the two light beams are adjusted by the focus lens system 460 in a superimposed state, and a predetermined amount of the test object is measured. Condensed on the incident optical axis, reflected on the surface of the test object or transmitted through the test object on the same measurement surface to form a light spot for each of the two lights,
The eccentricity of the test object is calculated based on the amount of deviation of the center of gravity of the total light amount of both light spots from the reference position. Here, the first and second light beams are adjusted so that the light amounts of both light beams are substantially equal to each other at the time of division, and the first light beam is different from the measurement light emission direction shift with respect to the measurement light emission direction shift. Since the same amount of shift occurs in the same direction and the second light is guided to the test object in such a manner as to cause the same amount of shift in the direction opposite to the first light, both of these lights are used. The eccentricity of the test object obtained based on the amount of deviation of the center of gravity of the total light amount of the spot from the reference position is a value in which the angular deviation between the two light beams caused by the deviation in the emission direction of the measurement light has been offset. . For this reason, even when the orientation of the light source 411 is unstable and the emission direction of the measurement light is deviated, or the optical axis of the focus lens system 460 is deviated, this does not affect the measurement result. Eccentricity measurement can be performed with high accuracy.

Further, since the measurement light passes through the focus lens system 460 before being split, the angle shift between the two lights caused by the optical axis shift of the focus lens system 460 is also canceled. Value. For this reason,
Even if the optical axis shift of the focus lens system 460 occurs, this does not affect the measurement result, and the eccentricity measurement of the test object can be performed with higher accuracy. In addition, since there is no measurement error due to the optical axis shift of the focus lens system 460, there is no need to rotate the test object around the optical axis, and the measurement work efficiency is improved. Furthermore, since a device for rotating the test object is not required, the measurement accuracy is improved, and the cost can be reduced.

[0139] Here, only the case where the reflection eccentricity of the test object which is a convex lens is measured and the case where the transmission eccentricity of the test object which is a concave lens is measured are described. By appropriately rearranging the composition of the system,
It is possible to measure the transmission eccentricity of the test object which is a convex lens, and to measure the reflection eccentricity of the test object which is a concave lens.

Next, an eccentricity measuring apparatus and an eccentricity measuring method according to the sixth invention will be described. FIG. 23 shows the first embodiment of the eccentricity measuring apparatus according to the sixth aspect of the present invention, which is an example in the case of measuring the reflection eccentricity of a test object 591 which is a convex lens. In this eccentricity measuring device, the measurement light emitted from the light source 511 is condensed by the lens 512 and enters the collimator lens 514 via the index 513 located at the converging point.

The measurement light converted into parallel light by the collimator lens 514 passes through a focus lens system 560 composed of a movable lens 561 composed of a biconvex lens and a fixed lens 562 composed of a biconcave lens, and is incident on a polarization beam splitter 521. Then, the polarization beam splitter 52
The measurement light incident on 1 is split into first light, which is P-polarized light transmitted through the semi-permeable film, and second light, which is S-polarized light reflected on the semi-permeable film. Here, it is not necessary to make the light amounts of the first light and the second light substantially equal (to make the light amount difference between the two lights extremely small). The reason is similar to the eccentricity measuring apparatus according to the second or fourth aspect of the present invention, in which the center of gravity of the light amount of the first light spot (first light spot) and the light spot of the second light (second light spot) are determined. This is because the center of gravity of the light amount of the light spot) is calculated separately, and the position of the center of gravity does not depend on the balance of the light amounts of the first light and the second light.

The first light transmitted through the semi-permeable film of the polarizing beam splitter 521 proceeds rightward in the figure as it is, passes through the quarter-wave plate 523, and passes through the first reflection surface 5 of the corner mirror 524.
24a. The first incident on the first reflecting surface 524a
The light is reflected downward in the figure and is incident on the second reflecting surface 524b of the corner mirror 524, where it is further reflected to the left in the figure, passes through the quarter-wave plate 525, and passes through the polarizing beam splitter 526. Light enters from the right side of the figure. Here, the first light was P-polarized light when transmitted through the semi-permeable membrane of the polarization beam splitter 521, but was reflected by the corner mirror 524 and entered into the polarization beam splitter 526 by two 1 / l. Since the light passes through the four-wavelength plates 523 and 525, the light is s-polarized when entering the polarization beam splitter 526 from the right. Therefore, the first light is reflected by the semi-permeable membrane of the polarizing beam splitter 526,
Go to the bottom of the figure.

On the other hand, the second light reflected on the semi-permeable film of the polarizing beam splitter 521 and traveling upward in the drawing is transmitted through the quarter-wave plate 527 and then reflected on the reflection mirror 528. Then, the light again passes through the quarter-wave plate 527 and enters the polarization beam splitter 521 from above in the drawing. Here, the second light was s-polarized light at the time when it was reflected upward in the figure at the semi-permeable membrane of the polarizing beam splitter 521,
The １ ／ wavelength plate 5 is used before the light is reflected by the reflection mirror 528 and returns to the polarization beam splitter 521 again.
27, the polarization beam splitter 5
21 is P-polarized when it is incident from above in the figure. For this reason, the second light passes through the semi-permeable film of the polarizing beam splitter 521, further passes through the semi-permeable film of the polarizing beam splitter 526, and proceeds downward in the figure in a state where the second light is superimposed on the first light. The corner mirror 524 has an appropriate position and posture such that the optical path lengths of the measurement light are equal to each other between the time when the measurement light is separated into the first light and the second light and the time when the two lights are overlapped again. Placed in

The first light and the second light emitted below the polarizing beam splitter 526 in the state of being superposed in this manner are superposed.
The light passes through the semi-permeable membrane of the beam splitter 529 installed below the polarizing beam splitter 526 (below in the figure), and then enters the surface of the test object 591. Here, the movable lens 561 of the focus lens system 560
Is adjusted so that both the first and second lights are focused on the focal position of the test object 591. As a result, an image of the index 513 is formed on the surface of the test object 591.

The first light focused at the focal position of the test object 591
The second light and the second light are reflected on the surface to be inspected of the object 591 to become parallel light, and enter the beam splitter 529 from below in the figure. Then, the light is reflected by the semi-permeable membrane of the beam splitter 529, advances to the right in the figure, and is incident on the deflection beam splitter 530 provided to the right (to the right in the figure) of the beam splitter 529. Here, the S-polarized first light is reflected on the semi-permeable film of the deflection beam splitter 530 downward in the figure, is collected by the lens 531 and is collected on the first measurement surface (the first light position detection element 571). A first light spot is formed on the light receiving surface. On the other hand, the P-polarized second light passes through the semi-permeable membrane of the deflection beam splitter 530 to the right in the drawing, is collected by the lens 532, and is collected on the second measurement surface (the second light position detection element 572). A second light spot is formed on the light receiving surface).

The measurement light emitted from the light source 511 is split into the first light, which is transmitted light, and the second light, which is reflected light by the polarizing beam splitter 521. Although the first light is guided to the surface to be inspected at 591, the first light passes through the polarizing beam splitter 521 to the right, and then the incident light and the reflected light are parallelized by the corner mirror 524 (light is reflected in the incident direction). A strong reflection,
Further, while the light is normally reflected by the semi-permeable membrane of the polarization beam splitter 526 to reach the test object 591, the second light reflected upward in the drawing by the polarization beam splitter 521 is:
After normal reflection by the reflection mirror 528, the light passes through the semi-permeable membranes of the two polarization beam splitters 521 and 526 as it is and reaches the test object 591. A shift of the same amount occurs in the same direction as the shift direction of the measurement light, and the second light shifts by the same amount in the direction opposite to the first light (see FIG. 8).

The first light position detecting element 571 detects the center of gravity of the light amount of the first light spot formed on the light receiving surface (first measurement surface), and outputs the result to the eccentricity calculator 580. Further, the second light position detecting element 572 has a light receiving surface (second
Of the second light spot formed on the (measurement surface) is detected, and the result is output to the eccentricity calculator 580 in the same manner. The eccentricity calculator 580 includes the first optical position detecting element 5
The light amount centroid of the second light spot detected by the second light position detection element 572 from the deviation angle of the first light obtained based on the deviation amount of the light amount centroid position of the first light spot from the reference position detected by the first light spot 71 The eccentricity of the test object 591 is calculated by subtracting the shift angle of the second light obtained based on the shift amount of the position from the reference position, and this is displayed on a display or the like.

Here, the reference position is the first light which is formed on the first measurement surface by the first light reflected on the surface of the test object 591 when the test object 591 has no eccentricity. The light intensity barycentric position of the spot and the light intensity barycentric position of the second light spot formed on the second measurement surface by the second light. When the test object 591 is not eccentric, the first and second lights are emitted from the test object 5.
Optical axis (incident optical axis) at the time of incidence on 91 and object 591
The optical axis (reflected optical axis) at the time of reflection coincides with the first light spot formed on the first measurement surface by the first light, the light intensity centroid position coincides with the reference position, and the second light coincides with the second light spot. Of light of the second light spot formed on the measurement surface of (1) also coincides with the reference position. However, when the test object 591 is eccentric, its reflected optical axis does not coincide with the incident optical axis (causes an angular deviation), so that the position of the light spot formed on each measurement surface by the two lights Are shifted from the reference position.

The posture of the light source 511 is unstable,
The emission direction of the measurement light is the reference direction (here, the test object 591
(In the direction of the predetermined incident optical axis), the reflected light axis of the first light on the test object 591 does not coincide with the incident optical axis regardless of the eccentricity of the test object 591. The center of gravity of the amount of light of the first light spot formed on the first measurement surface by the first light reflected by the surface to be inspected of the inspection object 591 and the second light spot formed by the second light on the second measurement surface The light quantity centroid position is shifted from the reference position.

Here, as described above, the first light and the second light have the same amount of shift in the same direction as the shift of the measurement light with respect to the shift of the measurement light with respect to the shift of the measurement light emission direction. , The second light is guided so as to cause the same amount of shift in the direction opposite to the first light, so that the shift of the light quantity centroid position of the first light spot formed on the first measurement surface from the reference position Quantity and the second
The amount of deviation of the center of gravity of the light amount of the second light spot formed on the measurement surface from the reference position is the same as the deviation of the measurement light in the emission direction. For this reason, based on the amount of deviation of the center of gravity of the light amount of the first light spot formed on the first measurement surface from the reference position and the amount of deviation of the center of gravity of the amount of light of the second light spot from the reference position (the second position). From the shift angle of the first light obtained based on the shift amount of the center of gravity of the light amount of one light spot from the reference position, the second light obtained based on the shift amount of the center of gravity of the light amount of the second light spot from the reference position is obtained. The eccentricity of the test object obtained by subtracting the shift angle is a value in which the angle shift between the two lights caused by the shift in the emission direction of the measurement light is offset, and the posture of the light source 511 is unstable and the measurement light This does not affect the measurement result even if the emission direction of the laser beam is shifted.

In the eccentricity measuring apparatus according to the sixth aspect of the present invention, similarly to the eccentricity measuring apparatus according to the fifth aspect, the eccentricity measuring apparatuses according to the first to fourth aspects of the present invention are described. Unlike the measurement device, the focus lens system 560 splits the measurement light (here, the deflection beam splitter 52).
1), the focus lens system 560 has an optical axis shift (when the optical axis of the movable lens 561 does not coincide with the optical axis of the fixed lens 562), the first and the second lenses are shifted. Since the two second lights are shifted by the same amount of angle, the position of the center of gravity of the light amount of the first light spot formed on the first measurement surface and the position of the second light spot formed on the second measurement surface The light amount center of gravity is shifted by the same amount as the shift of the measurement light in the emission direction. For this reason, when the eccentricity measurement of the test object 591 is performed using this device, the test object 591 is moved as in the case of the above-described eccentricity measurement devices according to the first to fourth inventions. It is not necessary to rotate around the optical axis and check whether the detected eccentricity is due to the test object or to the optical axis shift of the focus lens system.

FIG. 24 shows a second embodiment of the eccentricity measuring apparatus according to the sixth invention. The eccentricity measuring apparatus according to this embodiment is an example in the case of measuring the transmission eccentricity of a test object 592 which is a concave lens. This device has the basic configuration shown in the above-described first embodiment (FIG. 23), and includes a deflection beam splitter 526 in the first embodiment and a quarter-wave plate 525 located on the right side (right side in the drawing) of the deflection beam splitter 526. And the corner mirror 524 are removed, a corner cube 533 is set on the right side of the quarter-wave plate 523, and a test object 592 is arranged between the deflection beam splitter 521 and the beam splitter 529. A lens 534 is provided on the side, and a lens 535 is provided below the beam splitter 529 (below in the figure).

In this eccentricity measuring device, the measuring light converted into parallel light by the collimator lens 514 passes through the focus lens system 560 and enters the polarizing beam splitter 521 from the left side in the figure. Then, the measurement light that has entered the polarization beam splitter 521 is split into first light that is P-polarized light that passes through the semi-permeable film and second light that is S-polarized light that is reflected by the semi-permeable film. Here, it is not necessary to make the light amounts of the first light and the second light almost equal (so that the light amount difference between the two lights is extremely small). The reason is the same as in the above-described sixth embodiment of the present invention.

The first light transmitted through the semi-permeable film of the polarizing beam splitter 521 proceeds rightward in the figure as it is, passes through the quarter-wave plate 523, and is reflected by the corner cube 533. The first light reflected by the corner cube 533 again passes through the quarter-wave plate 523 and enters the polarization beam splitter 521 from the right side in the drawing. Here, the first light was P-polarized light when it passed through the semi-permeable membrane of the polarizing beam splitter 521 to the right in the drawing, but the corner cube 5
33, the reflected light is reflected again by the polarization beam splitter 521.
Since the light beam passes through the quarter-wave plate 523 twice before returning to the above, the light is S-polarized when it enters the polarization beam splitter 521 from the right. Therefore, the first
Light reflects off the semi-permeable membrane of the polarizing beam splitter 521 and travels downward in the figure.

On the other hand, the second light reflected on the semi-permeable film of the polarization beam splitter 521 and traveling upward in the drawing is transmitted through the quarter-wave plate 527 and then reflected on the reflection mirror 528. Then, the light again passes through the quarter-wave plate 527 and enters the polarization beam splitter 521 from above in the drawing. Here, the second light was s-polarized light at the time when it was reflected upward in the figure at the semi-permeable membrane of the polarizing beam splitter 521,
The １ ／ wavelength plate 5 is used before the light is reflected by the reflection mirror 528 and returns to the polarization beam splitter 521 again.
27, the polarization beam splitter 5
21 is P-polarized when it is incident from above in the figure. For this reason, the second light passes through the semi-permeable membrane of the polarization beam splitter 521, and travels downward in the drawing while being superimposed on the first light.

The first light and the second light emitted below the polarizing beam splitter
The light is incident on the surface of the test object 592 located below the polarization beam splitter 521 (below the drawing).
Here, the movable lens 5 of the focus lens system 560
The position of the first light 61 is adjusted so that both the first light and the second light are condensed at a position near the front focus of the test object 592. Thus, an image of the index 513 is formed on the surface of the test object 592. Then, the first and second lights condensed at a position near the front focal point of the test object 592 pass through the test object 592, become parallel light, and enter the deflection beam splitter 529 from above in the drawing. Here, the S-polarized first light is reflected rightward in the drawing on the semi-permeable film of the deflection beam splitter 529, is collected by the lens 534, and is collected on the first measurement surface (the first light position detecting element 571). A first light spot is formed on the light receiving surface of the first light spot. On the other hand, the P-polarized second light passes through the semi-permeable membrane of the deflection beam splitter 529 downward in the figure, is collected by the lens 535, and is collected on the second measurement surface (the second measurement surface).
A second light spot is formed on the light receiving surface of the light position detecting element 572).

As described above, the measuring light emitted from the light source 511 is divided into the first light as the transmitted light and the second light as the reflected light by the polarizing beam splitter 521, and the test light is superposed. It is led to the surface to be inspected of the object 591,
After the first light passes through the polarizing beam splitter 521 to the right, the incident light path and the reflected light path become specially parallel (reflect the light in the incident direction) due to the nature of the corner cube 533, and further, the polarized light beam While the second light is normally reflected by the semi-permeable film of the splitter 526, the second light is normally reflected by the reflection mirror 528, and then passes through the semi-permeable film of the polarization beam splitter 521. On the other hand, the first light has the same amount of shift in the same direction as the measurement light emission direction shift, and the second light has the same amount of shift in the direction opposite to the first light (see FIG. 8). ). For this reason, the same effect as that of the first embodiment can be obtained.

As described above, in the eccentricity measuring apparatus and the eccentricity measuring method according to the sixth procedure of the present invention, the light source 5
After dividing the measurement light emitted from 11 and transmitted through the focus lens system 560 into a first light and a second light, the two light beams are superimposed on each other and adjusted by the focus lens system 560 to adjust the predetermined amount of the test object. The first light is condensed on the incident optical axis, and the first light is reflected on the surface of the test object or transmitted through the test object, and the first light is guided to the first measurement surface to form a light spot. The two light beams are guided on the second measurement surface to form a light spot, and the shift amount of the first light spot from the reference position of the light amount centroid position and the shift amount of the second light spot from the reference position. The eccentricity of the test object is calculated based on. Here, the first and second lights are guided to the test object in such a state that the same amount of angular displacement is generated with respect to the amount of deviation of the measurement light in the emission direction. The eccentricity of the test object obtained based on the amount of deviation of the center of gravity of the light amount of the spot from the reference position and the amount of deviation of the center of gravity of the light amount of the second light spot from the reference position is determined by the deviation in the emission direction of the measurement light. This results in a value in which the angle shift between the two lights caused by the light is canceled. For this reason, even when the orientation of the light source 511 is unstable and the emission direction of the measurement light is shifted, the measurement result is not affected, and the eccentricity measurement of the test object can be performed with high accuracy. Become.

Further, since the measurement light passes through the focus lens system 560 before being split, the angle shift between the two lights caused by the optical axis shift of the focus lens system 560 is also canceled. Value. For this reason,
Even if the optical axis shift of the focus lens system 560 occurs, this does not affect the measurement result, and the eccentricity measurement of the test object can be performed with higher accuracy. Further, since there is no measurement error due to the optical axis shift of the focus lens system 560, it is not necessary to rotate the test object around the optical axis, and the measurement work efficiency is improved. Furthermore, since a device for rotating the test object is not required, the measurement accuracy is improved, and the cost can be reduced.

[0160] Here, only the case where the reflection eccentricity of the test object which is a convex lens is measured and the case where the transmission eccentricity of the test object which is a concave lens is measured are described. By appropriately rearranging the composition of the system,
It is possible to measure the transmission eccentricity of the test object which is a convex lens, and to measure the reflection eccentricity of the test object which is a concave lens. In the above embodiment, the split first and second light beams are guided so as to generate the same amount of angular deviation in directions opposite to each other with respect to the deviation of the measurement light emission direction.
As long as both lights are guided so as to generate the same amount of angular deviation with respect to the deviation in the emission direction of the measurement light, it is not always necessary that the two beams are deviated in the opposite directions.

In the fifth and sixth eccentricity measuring apparatuses according to the present invention, the configuration from the light source (411 or 511) to the movable lens (461 or 561) in the focus lens system (460 or 560) is the same. , The other components are each divided into two units, and the light source (411 or 511), which is both a vibration source and a heat source, and the test object are structurally separated from each other. Can also be reduced.

Although the preferred embodiments of the first to sixth aspects of the present invention have been described above, the above-described embodiments are merely examples for embodying the respective aspects of the present invention. Of course, it is also possible to adopt a system.

The eccentricity measuring device and the eccentricity measuring method according to the present invention are used in the process of manufacturing a high-precision lens. That is, the eccentricity with respect to the design value of the test object is measured, and after processing and polishing by a known method, the eccentricity with respect to the design value of the test object is measured again, and the eccentricity with respect to the design value of the test object is obtained. In the process of keeping it within the allowable range,
The eccentricity measuring device (or eccentricity measuring method) according to the present invention is applied. Then, the test object (optical element) having the predetermined eccentricity obtained in this manner is incorporated in a lens barrel to manufacture a projection lens for a projection exposure apparatus. As described above, a projection lens incorporating an optical element (lens) whose eccentricity has been measured using the eccentricity measuring device or the eccentricity measuring method according to the present invention is a very high-precision optical component with little eccentricity. Become.

[0164]

As described above, in the eccentricity measuring apparatus and the eccentricity measuring method according to the first to fourth aspects of the present invention, the eccentricity of the object to be measured is determined by the deviation of the measuring light emission direction. Because the angle shift between the two lights resulting from the cancellation is a value that is offset,
Even if the direction of emission of the measurement light is deviated due to the unstable posture of the light source, this does not affect the measurement result, and the eccentricity measurement of the test object can be performed with high accuracy.

Further, in the eccentricity measuring apparatus and the eccentricity measuring method according to the fifth and sixth aspects of the present invention, the eccentricity of the object to be determined is determined by the two eccentricities caused by the deviation of the measuring light emission direction. Since the angle deviation is canceled out, even if the orientation of the light source is unstable and the emission direction of the measurement light is deviated, or the optical axis of the focus lens system is deviated, this affects the measurement result. Therefore, the eccentricity measurement of the test object can be performed with high accuracy. Furthermore, since the measurement light passes through the focus lens system before being split, the angle shift between the two lights caused by the optical axis shift of the focus lens system is also canceled, and the focus lens system has Even when the optical axis shift occurs, this does not affect the measurement result, and the eccentricity measurement of the test object can be performed with higher accuracy. In addition, since there is no measurement error due to the optical axis shift of the focus lens system, there is no need to rotate the test object around the optical axis, and the measurement work efficiency is improved. Furthermore, since a device for rotating the test object is not required, the measurement accuracy is improved, and the cost can be reduced.

A projection lens incorporating an optical element whose eccentricity has been measured using the eccentricity measuring apparatus or method described above is an extremely high-precision optical component with little eccentricity.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an eccentricity measuring device according to a first embodiment of the first invention.

FIG. 2 is a diagram showing a path of a first light L1 and a second light L2 when a measurement light L emitted from a light source is shifted from a reference direction by an angle θ in the first embodiment of the first invention. is there.

FIG. 3 is a configuration diagram of an eccentricity measuring device according to a second embodiment of the first invention.

FIG. 4 is a configuration diagram of an eccentricity measuring device according to a third embodiment of the first invention.

FIG. 5 is a configuration diagram of an eccentricity measuring device according to a fourth embodiment of the first invention.

FIG. 6 is a configuration diagram of an eccentricity measuring device according to an embodiment of the second invention.

FIG. 7 is a configuration diagram of an eccentricity measuring device according to a first embodiment of the third invention.

FIG. 8 is a diagram showing the course of the first light L1 and the second light L2 when the measurement light L emitted from the light source is shifted from the reference direction by an angle θ in the third embodiment of the present invention. .

FIG. 9 is a configuration diagram of an eccentricity measuring device according to a second embodiment of the third invention.

FIG. 10 is a configuration diagram of an eccentricity measuring device according to a third embodiment of the third invention.

FIG. 11 is a configuration diagram of an eccentricity measuring device according to a fourth embodiment of the third invention.

FIG. 12 is a configuration diagram of an eccentricity measuring device according to a fifth embodiment of the third invention.

FIG. 13 is a configuration diagram of an eccentricity measuring device according to a sixth embodiment of the third invention.

FIG. 14 is a configuration diagram of an eccentricity measuring device according to a seventh embodiment of the third invention.

FIG. 15 is a configuration diagram of an eccentricity measuring device according to an eighth embodiment of the third invention.

FIG. 16 is a configuration diagram of an eccentricity measuring device according to a ninth embodiment of the third invention.

FIG. 17 is a configuration diagram of an eccentricity measuring device according to a tenth embodiment of the third invention.

FIG. 18 is a configuration diagram of an eccentricity measuring device according to an eleventh embodiment of the third invention.

FIG. 19 is a configuration diagram of an eccentricity measuring device according to a twelfth embodiment of the third invention.

FIG. 20 is a configuration diagram of an eccentricity measuring device according to an embodiment of the fourth invention.

FIG. 21 is a configuration diagram of an eccentricity measuring device according to a first embodiment of the fifth invention.

FIG. 22 is a configuration diagram of an eccentricity measuring device according to a second embodiment of the fifth invention.

FIG. 23 is a configuration diagram of an eccentricity measuring device according to a first embodiment of the sixth invention.

FIG. 24 is a configuration diagram of an eccentricity measuring device according to a second embodiment of the sixth invention.

[Explanation of symbols]

 Reference Signs List 11 light source 12 lens 13 index 14 collimator lens 20 beam splitter 31, 32, 33 lens 40 reflection transmitting plate 50 focus lens system 70 optical position detecting element (optical position detecting means) 80 eccentricity calculator (eccentricity calculating means) 91 Inspection

 ──────────────────────────────────────────────────続 き Continuing on the front page F term (reference) 2F065 AA11 AA17 BB03 BB16 BB22 CC22 DD00 FF01 GG04 HH03 HH04 HH13 JJ03 JJ05 LL04 LL09 LL12 LL17 LL36 LL37 LL46 MM04 PP01 PP13 PP22 QQ00 QQ25G04 2

Claims (23)

[Claims] 1. A light source, comprising: a first light source for measuring light emitted from the light source;
After splitting into the light and the second light, the first light
Only the light is focused on a predetermined incident optical axis of the test object, and the first light and the second light reflected on the test surface of the test object or transmitted through the test object are converted into the measurement light. The first light has the same amount of shift in the same direction as the emission direction shift of the measurement light with respect to the emission direction shift, and the second light has the same amount of shift in the direction opposite to the first light. An optical system that guides on the same measurement surface to form the light spots of the two lights in a state where the light spot is generated, and a light position for detecting the position of the center of gravity of the total light amount of the two light spots formed on the measurement surface Eccentricity comprising: detecting means; and eccentricity calculating means for calculating the eccentricity of the test object based on the total light quantity centroid position of the two light spots detected by the light position detecting means. measuring device. 2. A light source, and a measuring light emitted from the light source is divided into a first light and a second light, and both of the light are subjected to the same amount of angular displacement with respect to the amount of deviation of the measuring light in the emitting direction. After being guided to occur, only the first light of the two lights is condensed on a predetermined incident optical axis of the test object, and is reflected on the test surface of the test object or transmitted through the test object. Guiding the first light onto a first measurement surface to provide a first
An optical system that forms a light spot and guides the second light on a second measurement surface to form a second light spot; and an amount of light of the first light spot formed on the first measurement surface First light position detecting means for detecting the position of the center of gravity; second light position detecting means for detecting the position of the center of gravity of the amount of light of the second light spot formed on the second measurement surface; Eccentricity of the test object based on the light quantity centroid position of the first light spot detected by the light position detection means and the light quantity centroid position of the second light spot detected by the second light spot detection means And an eccentricity calculating means for calculating the eccentricity. 3. A light source, comprising: a first light source for measuring light emitted from the light source;
After splitting the light into the second light, the first light has the same amount of shift in the same direction as the shift in the emission direction of the measurement light with respect to the shift in the emission direction of the measurement light. The second light is converged on a predetermined incident optical axis of the test object in such a state that the same amount of shift occurs in a direction opposite to the first light, and is reflected on the test surface of the test object or An optical system that guides the two lights transmitted through the test object on the same measurement surface to form respective light spots of the two lights; and an overall light quantity centroid position of the two light spots formed on the measurement surface. Light position detecting means for detecting, and eccentricity calculating means for calculating the eccentricity of the test object based on the total light amount centroid position of the two light spots detected by the light position detecting means. Eccentricity measuring device. 4. A light source, and after dividing the measurement light emitted from the light source into a first light and a second light, these two lights are angularly displaced by the same amount with respect to the deviation in the emission direction of the measurement light. Is converged on a predetermined incident optical axis of the test object in such a state as to cause the first light of the two lights reflected on the test surface of the test object or transmitted through the test object to the first. An optical system that guides the second light on the measurement surface to form a first light spot and guides the second light on the second measurement surface to form a second light spot; First light position detecting means for detecting the position of the light quantity centroid of the first light spot, and second light for detecting the position of the light quantity centroid of the second light spot formed on the second measurement surface. Position detecting means, and the amount of light of the first light spot detected by the first light position detecting means Eccentricity calculation means for calculating the eccentricity of the test object based on a position and a light quantity gravity center position of the second light spot detected by the second light position detection means. Eccentricity measuring device. 5. A light source, and a measuring light emitted from the light source and transmitted through the focus lens system is divided into a first light and a second light having substantially equal light amounts. With respect to the direction shift, the first light has the same amount of shift in the same direction as the emission direction shift of the measurement light, and the second light has the same amount of shift in the direction opposite to the first light. In such a state, the focus lens system is adjusted to focus the light on a predetermined incident optical axis of the test object, and the two lights reflected on the test surface of the test object or transmitted through the test object are the same. An optical system that guides the light spots on the measurement surface to form respective light spots of the two light beams; a light position detection unit that detects a center of gravity of the total light amount of the two light spots formed on the measurement surface; Total light intensity barycentric position of both light spots detected by the detecting means An eccentricity calculating device for calculating the eccentricity of the test object based on the amount of deviation of the position from the reference position. 6. A light source, and after dividing the measurement light emitted from the light source and transmitted through the focus lens system into a first light and a second light, these two lights are converted into the deviation amount of the measurement light in the emission direction. The focus lens system is adjusted in such a state that the same amount of angular displacement is caused to converge on a predetermined incident optical axis of the test object, and is reflected on the test surface of the test object or the test object. Guides the first light of the two lights transmitted through the first measurement surface to form a first light spot, and guides the second light to a second measurement surface to form a second light spot. An optical system to be formed; first light position detecting means for detecting a light quantity centroid position of the first light spot formed on the first measurement surface; and the first light position detection means formed on the second measurement surface. A second light position detecting means for detecting a light quantity centroid position of the second light spot; The deviation amount of the light quantity centroid position of the first light spot detected by the first light position detecting means from the reference position and the reference of the light quantity centroid position of the second light spot detected by the second light spot detecting means. An eccentricity measuring device, comprising: eccentricity calculating means for calculating the eccentricity of the test object based on an amount of deviation from a position. 7. The condensing position may be a position near the center of curvature of the surface to be measured or a paraxial focal point of the surface to be measured when the condensed light is reflected by the surface of the object to be measured. The eccentricity measuring apparatus according to any one of claims 1 to 6, wherein the eccentricity measuring apparatus is located near the front focus position when the test object is transmitted. 8. The apparatus according to claim 1, wherein the test object is held by a holding member having a function of rotating the test object around the optical axis. Eccentricity measuring device. 9. The optical system according to claim 1, wherein the optical system includes the first light and the second light.
The eccentricity measuring apparatus according to any one of claims 1 to 8, further comprising an optical member having a function of reflecting one of the lights in the incident direction. 10. The eccentricity measuring apparatus according to claim 1, wherein the division is performed by a polarizing beam splitter or a transmission / reflection member. 11. After splitting a measuring light emitted from a light source into a first light and a second light having substantially equal light amounts, only the first light out of these two lights is positioned on a predetermined incident optical axis of the test object. And the first light and the second light reflected on or transmitted through the test object at the test surface of the test object, and the first light is The same amount of displacement occurs in the same direction as the exit direction of the measurement light, and the second light is on the same measurement surface in such a state that the same amount of displacement occurs in the opposite direction to the first light. An eccentricity measurement method for calculating the eccentricity of the test object based on the total light amount center of gravity of the two light spots. 12. A measuring light emitted from a light source is divided into a first light and a second light, and both of these lights are guided so as to cause an equal amount of angular deviation with respect to the amount of deviation of the measuring light in the emission direction. After that, only the first light of the two lights is condensed on a predetermined incident optical axis of the test object, and the first light reflected on the test surface of the test object or transmitted through the test object. On the first measurement surface to form a first light spot, and guide the second light on the second measurement surface to form a second light spot, and the light quantity centroid position of the first light spot An eccentricity measuring method for calculating the eccentricity of the test object based on the light amount gravity center position of the second light spot and the light amount centroid position of the second light spot. 13. After dividing the measuring light emitted from the light source into a first light and a second light having substantially equal light amounts, the first light is divided by the first light with respect to a shift in the emitting direction of the measuring light. A predetermined incident light of the test object is generated in such a state that the same amount of displacement occurs in the same direction as the emission direction of the measuring light and the second light produces the same amount of displacement in the opposite direction to the first light. The two lights condensed on an axis and reflected on or transmitted through the test object on the test surface of the test object are guided on the same measurement surface to form respective light spots of the two lights, An eccentricity measuring method, wherein the eccentricity of the test object is calculated based on the position of the center of gravity of the total light amount of the light spot. 14. After dividing the measuring light emitted from the light source into a first light and a second light, the two light are separated by the same amount with respect to the amount of deviation of the measuring light in the emitting direction. In the state, the first light is condensed on a predetermined incident optical axis of the test object, and the first light of the two lights reflected on the test surface of the test object or transmitted through the test object is reflected on the first measurement surface. To form a first light spot, and to guide the second light on a second measurement surface to form a second light spot, and to determine the light intensity centroid position of the first light spot and the second light spot. An eccentricity measuring method, wherein the eccentricity of the test object is calculated based on a light amount gravity center position. 15. After dividing the measurement light emitted from the light source and transmitted through the focus lens system into a first light and a second light having substantially equal light amounts, the two lights are separated with respect to a shift in the emission direction of the measurement light. The first light has the same amount of shift in the same direction as the emission direction shift of the measurement light, and the second light has the same amount of shift in the opposite direction to the first light. By adjusting the focus lens system, the light is condensed on a predetermined incident optical axis of the test object, and the two lights reflected on the test surface of the test object or transmitted through the test object are on the same measurement surface. Eccentricity of the test object is calculated based on the amount of deviation of the center of gravity of the total light quantity of the two light spots from the reference position. Measuring method. 16. After dividing the measurement light emitted from the light source and transmitted through the focus lens system into a first light and a second light,
Both of these lights are adjusted on the focus lens system in a state where the same amount of angle shift is generated with respect to the emission direction shift amount of the measurement light, and are condensed on a predetermined incident optical axis of the test object,
The first light of the two lights reflected on the test surface of the test object or transmitted through the test object is guided on a first measurement surface to form a first light spot, and the second light spot is formed on the first measurement surface.
The light is guided on the second measurement surface to form a second light spot, and the amount of deviation of the light quantity centroid position of the first light spot from the reference position and the light quantity centroid position of the second light spot from the reference position are determined. An eccentricity measuring method, wherein the eccentricity of the test object is calculated based on a shift amount. 17. The condensing position may be a position near a center of curvature of the surface to be measured or a paraxial focus of the surface to be measured when the condensed light is reflected on the surface to be measured of the object. The eccentricity measuring method according to any one of claims 11 to 16, wherein the eccentricity measuring method is a position near the front focal point of the test object when the test object is transmitted therethrough. 18. The apparatus according to claim 1, wherein the test object is held by a holding member having a function of rotating the test object around the optical axis. Eccentricity measurement method. 19. The displacement of the first light with respect to the displacement of the measurement light in the emission direction causes the same amount of displacement in the same direction as the displacement of the measurement light in the emission direction, and the second light is different from the first light. 19. The optical member having a function of reflecting the first light or the second light in the incident direction, in which the same amount of displacement occurs in the opposite direction, is performed. 3. The eccentricity measurement method described in 1. above. 20. The apparatus according to claim 20, wherein the first light shifts in the same direction as the emission direction shift of the measurement light, and the second light shifts in a direction opposite to the first light. 17. The eccentricity measuring method according to claim 12, wherein the eccentricity is measured. 21. The eccentricity measuring method according to claim 11, wherein the division is performed by a polarizing beam splitter or a transmission / reflection member. 22. A projection lens incorporating an optical element whose eccentricity has been measured using the eccentricity measuring device according to claim 1. Description: 23. A projection lens comprising an optical element whose eccentricity has been measured using the eccentricity measuring method according to claim 11.