JP3261762B2 - Interferometer device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an interferometer for inspecting and measuring the surface accuracy of an object to be inspected by an interference effect of a laser beam.

[0002]

2. Description of the Related Art For example, there is a laser interferometer as a measuring instrument for inspecting and measuring lenses and other precision optical products. As this laser interferometer, for example, a Fizeau interferometer as shown in FIG. 1 is used.

In the figure, reference numeral 1 denotes an interferometer main body, and the main body of the interferometer 1 is provided with a laser oscillator 2 composed of a He-Ne laser or the like, and a laser beam emitted from the laser oscillator 2 is reflected. It is bent 90 ° by the mirror 3. The laser beam bent by the reflection mirror 3 is incident on a beam splitter 5 while expanding the beam via a lens 4 for expanding the beam.
The beam splitter 5 has a reflecting surface 5a, and the incident light from the laser oscillator 2 is reflected by the reflecting surface 5a and is again reflected by 90 °.
The direction is changed, and the light is collimated by a collimator lens 6 provided in the middle of this optical path. Collimator lens 6
A reference lens 7 is disposed at a position in front of.

The reference lens 7 has a reference surface 7b having a spherical surface on the surface opposite to the incident surface 7a, and the incident surface 7a is coated with an anti-reflection coating. A part of the laser light incident on the reference lens 7 is reflected by the reference surface 7b, and most of the laser light is transmitted through the reference lens 7 and the test surface 8a of the test lens 8 set at a position in front of the optical path. And a part of the light is reflected by the test surface 8a. Then, the reflected light from the test surface 8a and the reflected light from the reference surface 7b of the reference lens 7 interfere with each other to generate interference fringes.
The reflected light having such interference fringes is transmitted to the collimator lens 6.
Passes through the reflecting surface 5a of the beam splitter 5, and enters the imaging means 10 including a CCD camera or the like via the interference fringe imaging lens 9, and the imaging means 10
, An interference fringe is photographed, and the image can be displayed on a monitor device (not shown).

In the above-described interferometer device, if the test lens 8 is arranged above the reference lens 7,
The positioning and holding of the test lens 8 on the lens mount portion 11 becomes easy, and the work of setting and removing the test lens 8 by an automatic machine can be performed smoothly and reliably. Moreover, with the interference fringes in a stable state,
In order to enable smooth and accurate observation, the interferometer main body 1 and the lens mount 11 must be held so that external vibrations are not transmitted. For this purpose, the surface plate is provided in a horizontal state, and the interferometer body 1 is mounted on the lower surface of the surface plate, and the lens mount 11 is mounted on the upper surface. A light-guiding through hole for forming an optical path between the lens 8 and the test lens 8 set in the lens mount 11 is provided. The surface plate is connected to the support member. By interposing a vibration isolating member between the surface plate and the support member, external vibration is not transmitted to the surface plate.

[0006]

In setting the lens to be measured on the lens mount, the lens to be measured is held at a predetermined position by its own weight. For accurate operation, the surface plate provided with the lens mount must be horizontal. As the vibration isolating member interposed between the surface plate and the support member, a pneumatic type is usually used. In order to maximize the vibration absorbing ability of the vibration isolating member, a predetermined air pressure is required. State. However, these operations of adjusting the position of the surface plate and adjusting the air pressure of the vibration isolating member cannot always be performed smoothly. In particular, since the surface plate needs to be adjusted in relation to both the support member and the vibration isolating member, it is extremely difficult to adjust the level of the surface plate, and the pressure adjustment of the vibration isolating member is also difficult. It is not always easy to do exactly.

The present invention has been made in view of the above points, and an object of the present invention is to make it possible to adjust a surface plate and an anti-vibration member extremely easily.

[0008]

In order to achieve the above-mentioned object, according to the present invention, a support plate is supported on a support member via a pneumatic vibration isolator, and an interferometer main body is provided on a lower surface of the base plate. An interferometer device mounted and provided with a mount portion on the upper surface on which a test object is mounted, wherein the support member is a base.
The base has a flatness detecting means.
Level is detected and the position is adjusted to be horizontal.
A base plate angle adjusting unit is provided, and a platen level detecting unit that can visually detect a relative height position of the platen with respect to the support member is provided between the support member or a member connected thereto and the platen. It is, varying the pressure of the damping member
When the height position of the surface plate is changed by changing
Then, the height position of the platen is determined by the platen level detecting means.
The platen is connected to the support member or to the support member.
To the specified height position with respect to the set member
Thus, the vibration isolating member can exhibit a desired vibration absorbing ability, and the position of the surface plate can be adjusted in a horizontal state.

[0009]

Since the surface plate is provided with a mount on which the object to be tested is mounted, it is ideally required to be in a horizontal state. Also, in order to maximize the vibration absorption function of the vibration isolation member, even if its air pressure is too low,
It should not be too high and must be at a certain level. Therefore, in order to hold the surface plate in a horizontal state, first, the support member is set to a state where there is no inclination. For this purpose, the base part angle adjusting means in the base part of the support member is adjusted so that the base part is in a horizontal state. The adjustment of the base portion can be performed while checking the horizontality by the horizontality detecting means. After the adjustment of the support member is completed, the air pressure of the vibration isolating member is adjusted next. The adjustment of the air pressure is performed while visually confirming the relative position of the surface plate with respect to the support member by the surface level detector. This allows the surface plate to maintain a constant
It is at a height position and is adjusted to a horizontal state. Moreover, when the surface plate is in a horizontal state, the air pressure of the vibration isolator is naturally adjusted to an appropriate value.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. 2 and 3 show the overall configuration of the interferometer device. In the drawing, reference numeral 20 denotes a support member, the support member 20 includes a base portion 20a and a peripheral wall portion 20b,
On the lower surface of the base portion 20a, four height adjusting leg rods 21 are provided. By rotating the leg rod 21, the length of the protrusion from the base portion 20a can be adjusted. Above the peripheral wall portion 20b, vibration isolating members 22 are provided at four places, and a surface plate 23 is installed on the vibration isolating members 22. The interferometer main body 1 is suspended from the lower surface of the surface plate 23, and the lens mount 11 for setting the lens 8 to be detected is mounted on the upper surface side. Here, the lens mount unit 11 is configured such that the optical axis of the interferometer main body 1 and the test lens 8 set in the lens mount unit 11 are arranged.
The lens mount unit 11 includes an XY stage 12 and a Z fine adjustment stage 13, and a lens set unit is mounted on the Z fine adjustment stage 13. 14 are provided. On the other hand, the interferometer body 1 has a reference lens 7 and a test lens 8.
The interferometer main body 1 needs to be able to adjust the distance between
It is attached to. The surface plate 23 has an interferometer body 1
In order to allow the laser light from the laser beam to pass through and strike the lens 8 set on the lens mount 11, a light-guiding through hole 23a is provided. When the test lens 8 is a spherical lens, the Z fine adjustment stage 13 does not always need to be provided.

An extension 20c is extended upward from the support member 20, and a platen cover for protecting the extension 20c from swinging by touching the platen 23 with a hand or the like. 2
4 are connected. The platen cover 24 has an opening 24.
a is formed, and the lens set portion 14 of the lens mount portion 11 projects upward from the opening 24a.

Here, the vibration isolating member 22 is for preventing the vibration from the supporting member 20 from being transmitted to the surface plate 23. As shown in FIG. A lower housing 30 fixed to the support member 20 side;
An upper housing 31 fixed to the surface plate 23 and a flexible film 32 provided between the housings 30 and 31 are provided. The interior of the housings 30 and 31 and the space surrounded by the flexible film 32 are sealed. The air pressure chamber 33 is provided. By supplying air at a predetermined pressure to the inside of the air pressure chamber 33, the platen 23 is supported by the support member 20 by this air pressure.
The vibration on the support member 20 side is absorbed by the vibration isolating member 22 and is prevented from being transmitted to the surface plate 23.

The vibration isolating members 22 are provided at four corners of the surface plate 23, and as shown in FIG. 5, these can be individually adjusted in air pressure. In this figure, suffixes a to d are given to each of the vibration isolating members 22 at the four corners. Air pipes 34a to 34d are connected to the four vibration isolating members 22a to 22d, respectively. Of these air pipes 34a to 34d, 34a and 34b are connected to single air reservoirs 35a and 35b, respectively. , And the air pipes 34c and 34d share a common air reservoir 35.
c. And each of these air reservoirs 35a
Air supply pipes 36a to 36c are connected to .about.35c, and cocks 37a to 37c are provided in the middle of the air supply pipes 36a to 36c. The air supply pipes 36a to 36c are connected to a supply pipe 38, and the supply pipe 38 is connected to an air pressure source 39 such as a cylinder. Therefore, if the cocks 37a to 37c are operated,
The air pressure of the vibration isolating members 22a to 22d can be individually adjusted. However, since the vibration isolating members 22c and 22d are connected to the common air reservoir 35c, the two vibration isolating members 22c and 22d are always in the same pressure state.

In the interferometer device having the above configuration, the inside of the pneumatic chamber 33 of each vibration isolating member 22 must be in a predetermined pressure state in order to more reliably absorb the vibration on the supporting member 20 side. . In addition, since the lens mount 11 is provided on the upper surface of the surface plate 23 and the lens 8 to be measured is positioned on the lens set portion 14 by its own weight, it is necessary to precisely position the lens 8 to be measured by the surface plate. 2
3 must be exactly horizontal.

In order to arrange the surface plate 23 in a horizontal state, the peripheral wall portion 20b of the support member 20 is in a state where there is no inclination. For this reason, even if the floor surface on which the support member 20 is provided has irregularities, the base portion 20a is adjusted so as to be horizontal. For this purpose, a horizontality detecting means and a base part angle adjusting means are provided. The level detecting means is provided with an indicator 40 shown on the upper surface of the base 20a of the support member 20.
And this weight 41. The index 40 is formed by forming a predetermined scale in the XY axis direction with the origin point being the intersection of a line connecting the height adjusting leg bars 21 and 21 provided at opposing positions. Is suspended from the lower surface of the surface plate 23 by a thread 42, and the base portion 20a
Is in a horizontal state, the weight 41
Has been adjusted to point to the origin. Therefore, when the weight 41 is displaced in any direction from the origin position, it is detected that the base portion 20a is tilted, and the height of the height adjusting leg 21 is adjusted. Thus, the support member 20 can be adjusted so as not to be inclined. Accordingly, the leg portion 21 constitutes a base portion angle adjusting means.

As described above, when the base portion 20a of the support member 20 is horizontal and the peripheral wall portion 20b is in a state where there is no inclination, the platen 23 is brought into a positional relationship parallel to the base portion 20a of the support member 20. If adjusted, the platen 23 will be in a horizontal state. The position adjustment of the surface plate 23 is performed by adjusting the air pressure in the vibration isolating member 22. Then, in a pneumatic state in which the vibration isolating member 22 exhibits the maximum vibration absorbing ability, the surface plate 23 is set in advance so as to be in a horizontal state. As a result, when the air pressure of the vibration isolating member 22 is in an appropriate state, the platen 23 is adjusted to be in a horizontal state.

In order to easily adjust the air pressure of the vibration isolating member 22, as shown in FIG.
Is formed with a mark 43 for level display functioning as a platen level detecting means. The mark 43 is set such that the platen 23 is horizontal and the air pressure of the vibration isolating member 22 is in an appropriate state when the mark 43 is at a height position coincident with the upper surface of the platen cover 24.

With the above-described configuration, for example, the floor where the interferometer device is installed is not flat,
Even when there are some irregularities, the index 40 of the weight 41
The leg portion 21 is appropriately screwed in and out while confirming the relative position with respect to the base portion 20a of the support member 20.
Can be adjusted to be horizontal, so that the support member 20 can be adjusted.
Of the peripheral wall portion 20b can be in a state without inclination.
Here, the indicator 40 is formed on the upper surface of the base portion 20a,
In addition, since the leg 21 is also attached to the base portion 20a, the operator can easily confirm the
1 can be adjusted, and it is not necessary to change the posture during the work, so that the work can be smoothly performed.

Next, after the supporting member 20 is adjusted to an appropriate state, the cock 37 is operated to supply air to the vibration isolating member 22 and to discharge air therefrom.
The height position of the platen 23 with respect to the support member 20 is adjusted. The height adjustment of the platen 23 is performed while checking the mark 43, and the mark 43 is attached to the opening 24 a of the platen cover 24.
, The table 23 is adjusted to be horizontal, and the vibration isolating member 22 is adjusted to a state of maximizing the vibration absorbing ability. Here, the lens mount 11 and the interferometer main body 1 are attached to the surface plate 23.
It is normal that the center position is not the position of the center of gravity. Therefore, when the four provided vibration isolating members 22a to 22d are in the same pressure state, the surface plate 23 does not become horizontal, Tilts out. Therefore, each of these vibration isolating members 22a to 22a
2d is individually pressure-adjusted. However, the vibration isolating member 22
c and 22d have the same pressure, but the inclination is adjusted by adjusting the height of the other two corners of two of the four corners of the surface plate 23. However, the adjustment is easier than when the four corners are individually adjusted. However, it is also possible to make it possible to individually adjust the pressure of all the four vibration isolating members 22a to 22d.

Thus, when the test lens 8 is set on the lens mount section 11, the entire contact portion of the test lens 8 comes into contact with the lens setting section 14 with a uniform load.
For example, when the test lens 8 is a spherical lens, 1
Although the projections are supported by three projections every 20 °, the load of the contact portion at these three points becomes uniform. As a result, the test lens 8 is set extremely stably, and if the curved surface portion of the test lens 8 is brought into contact with the test lens 8, the load of the test lens 8 also exerts a self-centering effect. . As described above, when the positioning accuracy of the lens 8 to be inspected is improved, it is possible to accurately observe the interference fringes, and the accuracy of the inspection is significantly improved. Moreover, since the vibration isolating member 22 exhibits the maximum vibration absorbing ability, the observed interference fringes are also stabilized, and the inspection accuracy and efficiency are further improved.

After a long time, the pressure of the vibration isolating member 22 may decrease. In this case, the platen 23 is inclined, and the vibration absorbing ability is also reduced. Therefore, it is preferable that the pressure state in the air pressure chamber 33 of the vibration isolating member 22 can always be recognized. By connecting a pressure gauge to the air reservoirs 35a to 35c or the like, the fluctuation of the pressure in the air pressure chamber 33 can be detected.
If the pressure fluctuates, the position of the surface plate 23 with respect to the support member 20 fluctuates.
Since the mark 43 can be confirmed by visual inspection, the mark 43 also functions as a monitoring mechanism of the pressure state in the pneumatic chamber 33 of the vibration isolating member 22.

In the above-described embodiment, a mark 43 is formed on the lens mount section 11 as the platen level detecting means, and the mark 43 is connected to the platen cover 24 connected to the support member 20. Although it is configured to detect the relative positional relationship between the platen, in the case where the platen cover is not provided, for example, by providing a scale plate for indicating the height position of the upper surface of the platen on the support member, etc. Level detecting means can be configured. As the levelness detecting means, various levels, etc. may be used in addition to those described above.

[0023]

As described above, according to the present invention, the base portion of the supporting member for supporting the surface plate is leveled by the flatness holding means comprising the flatness detecting means and the base portion angle adjusting means. adjusted to, also between the support member or members and plate coupled thereto, provided with a detectable platen level detecting means by eye relative height position relative to the support member of the surface plate, antivibration Change the air pressure of the components
When adjusting the height position of the surface plate, the surface plate level detection means
By setting the surface plate to a predetermined height position, the surface plate is in a horizontal state, so that the vibration isolating member is adjusted to exhibit the desired vibration absorption capacity, so with a simple configuration,
This adjustment can be performed very easily and accurately without special skill, and the effect is obtained.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of an interferometer apparatus.

FIG. 2 is an external view of an interferometer apparatus showing one embodiment of the present invention.

FIG. 3 is a sectional view of FIG. 2;

FIG. 4 is a cross-sectional view of an anti-vibration member.

FIG. 5 is an explanatory diagram of a configuration of an air pressure adjusting mechanism of a vibration isolating member.

FIG. 6 is an enlarged view of a main part of FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Interferometer main body 7 Reference lens 8 Test lens 11 Lens mount part 20 Support member 20a Base part 21 Height adjustment leg 22, 22a-22d Anti-vibration member 23 Surface plate 23a Through hole 24 Surface plate cover 24a Opening 40 Indicator 41 Weight 43 mark

Claims (3)

(57) [Claims] 1. A base plate is supported on a support member via a pneumatic vibration isolating member, an interferometer body is mounted on a lower surface of the base plate, and a mount portion on which a test object is mounted is mounted on an upper surface. In the interferometer device provided, the support member has a base portion, and the base portion has water.
The flatness is detected by the flatness detection means,
A base angle adjustment means is provided to adjust the position
Between the support member or the member connected thereto and the surface plate, the relative height position of the surface plate with respect to the support member is visually observed.
A platen level detecting means capable of detecting the platen is provided, and the platen is changed by changing an air pressure of the vibration isolating member.
When the height position of the platen is changed,
The platen is detected by the platen level detecting means, and the platen is
Predetermined height for the support member or the members connected to it
By adjusting such a position, the interferometer device the conjunction to exhibit desired vibration absorption capacity antivibration member, characterized in that the surface plate and the position adjustment can be configured in a horizontal state. 2. The interference according to claim 1, wherein the horizontality detecting means is formed by an index formed on a base plate of the support member and a weight suspended from the surface plate with a thread. Instrument. 3. A surface plate cover connected to a support member is provided at a position on the surface plate, and an opening is formed in the surface plate cover so that the mount portion is exposed to the outside. 2. The interferometer device according to claim 1, wherein a level display mark is provided on the base plate so as to serve as the platen level detecting means.