JPH02211416A - Deflector and outside diameter measuring instrument formed by using this deflector - Google Patents

Abstract

PURPOSE:To obtain a sufficient number of scanning times and a sufficient deflection angle by providing a lens which adjusts the luminous flux between a light source and a tuning fork oscillator and providing a driving part for controlling the oscillator. CONSTITUTION:The laser light of the light source 1 has the prescribed deflection angle by a concave mirror 8 of the tuning fork oscillator 3 and is outputted to the outside by the oscillation of the tuning fork oscillator 3. The lens 6 is disposed between the light source 1 and the oscillator 3 and the state of the convergence and divergence of the luminous flux is adjusted by this lens. The reflected light is partly outputted by a half mirror 4 to a monitor section 5a and the oscillation of the tuning fork oscillator 3 is controlled accordance with the result of the detection in the monitor section 5a. The outside diameter of an object to be measured W is calculated from the time of the shaded part of the work by irradiation of this laser light. The deflection angle is made as large as >=5 times heretofore and the sufficient number of scanning times are obtd.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a deflector that deflects light from a light source to a desired angle, and an outer diameter measuring device that uses this deflector to measure the outer diameter of an object to be measured. It is related to.

[Prior Art 1] Deflectors such as rotating mirrors and tuning fork deflectors are known as devices that output a light beam emitted from a light source with a predetermined deflection angle. As an application example, this deflector scans the light beam parallel to the optical axis and irradiates the object to be measured, and calculates the time during which the light beam hits the object and becomes a shadow, thereby determining the outer diameter of the object. It is applied to the outer diameter measuring device.

FIG. 5 shows a schematic configuration of a deflector conventionally used as an apparatus for measuring the outer diameter of an object to be measured.

The deflector shown in this figure includes a light source 20 that emits a laser beam,
A rotating mirror 21 that is driven by a motor driver 31 and outputs a laser beam supplied from a light source 20 via a mirror 32 at a predetermined deflection angle θ, and a light source that is provided between the optical path of the light source 20 and the rotating mirror 21. 20, and a mirror 22 that makes the laser beam from 20 enter a rotating mirror 21. The rotating mirror 21 obtains the required deflection angle θ2 of the laser beam.

In addition, a deflector using a tuning fork vibrator instead of the rotating mirror 21 described above has a plane mirror attached to the tip of the tuning fork vibrator, although not particularly shown, and the laser beam from the light source is transmitted through the mirror to the tuning fork. The laser beam is made incident on the plane mirror of the vibrator, and is deflected at a predetermined angle through the plane mirror, and is scanned by the vibration of the tuning fork vibrator. Further, a half mirror is disposed on the optical path between the plane mirror and the object to be measured, and the amplitude and phase of the laser beam branched by the half mirror are detected by the monitor section of the drive section. Based on this detection result, the vibration of the tuning fork vibrator is controlled by the drive circuit.

FIG. 6 shows a specific configuration in which the deflector using the above-mentioned tuning fork vibrator is incorporated into the light projecting section of the outer diameter measuring device.

That is, each component constituting this deflector is positioned within the casing 29 with the distance between each component kept constant, and the laser beam emitted from the light source 25 passes through the plane mirror 24 of the tuning fork vibrator 23. It is reflected by the mirror 27 and guided to the first mirror 26a via the half mirror 27. At this time, a portion of the laser beam is reflected by the half mirror 27 and guided to the monitor section 28 via the mirror 26b. The laser beam reflected by the mirror 26a is guided to the mirror 26c located slightly to the right of the lower center of the housing 29. Furthermore, this mirror 2
The laser beam reflected by 6c is guided to a mirror 26d located on the lower left side of the housing 29, and then this mirror 26d
The light is emitted to the outside via a lens 3o provided to face d. Then, this laser light is transmitted through the lens 30.
The object to be measured is scanned parallel to the optical axis of the laser beam, and the object to be measured is irradiated with the laser beam, and the outer diameter of the object to be measured is determined from the time of the portion of the object to be measured that is shaded by the laser beam irradiation, as described above.

Problems to be Solved by the Invention] However, the above-described conventional deflector and an outer diameter measuring device using this deflector have the following problems.

That is, with the deflector using the rotating mirror 21 described above, a sufficiently large deflection angle θ8 can be obtained, but since the rotating mirror 21 is configured to be mechanically driven, this cannot be applied to an outer diameter measuring device. In this case, the response speed is limited by the processing unit, so even if the number of scans is high, it will be 400~
The number of scans is less than 500 times/s, and since the scan is performed in one direction, there is a problem that it is susceptible to adverse effects when the object to be measured vibrates.

In addition, the deflector using the tuning fork vibrator 23 described later enables reciprocating scanning of the laser beam, and the above-mentioned scanning number can be performed more than 1000 times/s, and the above-mentioned influence when the measured object is vibrating. can be made smaller. However, the current deflector using the tuning fork S mover 23 has a deflection angle θ of 150 mra.
If the angle of deflection is less than d, it is not possible to obtain a sufficient deflection angle.
It is necessary to increase the scanning width by increasing the focal length (f) of the lens 4 (fθ lens). Therefore, it was necessary to extend the optical path between the mirror 24 at the tip of the tuning fork vibrator 23 and the lens 14 by disposing a plurality of mirrors 26 on the optical path. For this reason,
The number of parts is large, which leads to measurement errors due to movement of the object in the scanning space due to the influence of mechanical and optical errors caused by multiple mirrors (it also takes up more installation space than necessary, making the device difficult to use). There was a problem with increasing the size.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and the object thereof is to provide a deflector that can obtain stable beam deflection with a sufficient number of scans and a deflection angle, and to provide a highly accurate and compact deflector. It is an object of the present invention to provide an outer diameter measuring device using the deflector, which can achieve the following.

[Means for Solving the Problems] In order to achieve the above object, a deflector according to the present invention includes a light source, a tuning fork vibrator provided with a concave mirror that emits a light beam from the light source at a predetermined deflection angle, and A lens provided on an optical path between a tuning fork vibrator and the light source to adjust convergence and divergence states of the deflected light beam, and a drive unit to control driving of the tuning fork vibrator. It is said that

In addition, an outer diameter measuring device using this deflector includes a light source, a tuning fork vibrator provided with a concave mirror that emits a light beam from the light source with a predetermined deflection angle, and a space between the tuning fork vibrator and the light source. a deflector, which is provided on the optical path of the deflector, and includes a lens that adjusts the convergence and divergence states of the deflected light beam, and a drive section that controls the driving of the tuning fork vibrator; and a light beam emitted from the deflector. a lens for scanning parallel to the optical axis, a lens for converging the light flux passing from the lens through the object to be measured, a light receiver for receiving the light flux converged by the lens, and a light receiver for receiving the light flux from the light receiver. The apparatus is characterized by comprising a processing section that calculates the outer diameter of the object to be measured based on the obtained signal and the signal obtained from the drive section.

[Operation] The light beam emitted from the light source of the deflector is deflected at a predetermined deflection angle by the concave mirror while its convergence and divergence are adjusted by a lens disposed on the optical path and a concave mirror provided in the tuning fork vibrator. It is output to the outside by the vibration of the tuning fork vibrator. In this case, the deflection angle is not only determined by the conventional tuning fork vibrator, but also expanded by a concave mirror.

In an outer diameter measuring device using this deflector, the light beam from the deflector is scanned parallel to the front axis of the lens using a lens and irradiated onto the object to be measured. The light flux that has passed through the object to be measured due to the light irradiation from the deflector is received by the detection processing section, and the outer diameter of the object to be measured is calculated based on the received light and the signal from the drive section.

[Embodiment 1] FIG. 1 is a schematic diagram showing an embodiment of a deflector according to the present invention.

The deflector according to this embodiment is applied to an outer diameter measuring device that scans the object to be measured with a light beam at a predetermined deflection angle and measures the outer diameter of the object by scanning the light beam.
Light source 1. Mirror 2, tuning fork vibrator 3, half mirror 4, drive unit 5. A lens 6 and a lens 14 are housed in a housing 7 and are generally configured.

The light source l outputs a laser beam, and the laser beam is reflected by the mirror 2 to the tuning fork vibrator 3111. A concave mirror 8 is fixed at the tip of each tuning fork vibrator 3. This concave mirror 8 is used to emit a light beam with a sufficient scanning width to the object W to be measured (to obtain a deflection angle θ). The deflected light may be transmitted through the lens 14 and output to the object W while being sinusoidally scanned back and forth at the natural frequency of the tuning fork vibrator 3.

Here, since the tuning fork oscillator 3 driven by the natural frequency is used to scan the light beam irradiated onto the object to be measured, the object to be measured W can be scanned back and forth with the laser beam. By using a concave, cylindrical, or aspheric mirror at the tip, the deflection angle can be improved by more than five times compared to a conventional tuning fork deflector. Therefore, as mentioned above, the focal length of the lens 14 (fθ lens) can be made small, and the number of mirrors between the concave surface [8 and the lens 14 can also be reduced, so optical errors can be reduced. Therefore, highly accurate measurements can be performed.

The half mirror 4 reflects a part of the light from the concave surface 11B, and this reflected light is output to the drive unit 5.

The drive unit 5 includes a monitor unit 5a and a drive circuit 5b, and the monitor unit 5a detects the amplitude and phase of the laser beam reflected and guided by the half mirror 4. Further, the four drive circuit 5b constantly controls the vibration of the tuning fork vibrator 3 based on the detection result of the monitor section 5a.

A lens 6 disposed on the optical path between the light source l and the tuning fork vibrator 3, together with the concave mirror 8 of the tuning fork vibrator 3,
The degree of convergence and divergence of the laser beam deflected by f48 is adjusted.

Next, FIG. 2 shows an embodiment of an outer diameter measuring device equipped with the above-mentioned deflector.

In this outer diameter measuring device, the above-mentioned deflector 10 and the object to be measured W are used.
A light receiving section 11b is installed at a position opposite to each other with the laser beam irradiated from the deflector 1O. Then, in the processing section 18, the light receiver 1
7 and the monitor section 5a to calculate the outer diameter value of the object to be measured and the position of the object in the X direction.

Furthermore, in this light receiving section 11b, the outer diameter φ of the object W to be measured is
To explain in detail the operation of calculating , the light received after passing through the object W is photoelectrically converted, and then output to two sample and hold circuits (not shown) controlled by the photoelectrically converted signals. be done. In the sample hold circuit, a sinusoidal signal representing the position in the X direction of the scanning light beam generated by the monitor section 5a of the deflector 10 is sent to the object W to be measured.
Hold at the time corresponding to both edges of. Further, the difference between the signals from each sample and hold circuit is calculated, and a signal proportional to the outer diameter φ of the object W to be measured is output. This signal is A/D converted and transferred to the processing section 18, where the outer diameter value φ of the object W to be measured is calculated.

FIG. 3 shows an embodiment of the outer diameter measuring device.

Note that the light projecting section 11a shown in FIG. 3 and the conventional light projecting section shown in FIG. The light projecting section 11a according to the embodiment can shorten the optical path to the minimum, and does not require installation space even when applied to an outer diameter measuring device, so that the device itself can be made compact.

The detection section 9 of this outer diameter measuring device includes the aforementioned light source 1, mirror 2, tuning fork vibrator 3. A light projecting section 11a in which parts such as a half mirror 4, a driving section 5, and a lens 6 are positioned and fixed at a predetermined distance, and a laser beam emitted from the light projecting section 11a and guided through the object W to be measured. The light receiving section 11b receives the light.
are configured in separate housings 7 and 12, respectively, and form one base 1.
3 at a predetermined distance.

Next, the operation of the outer diameter measuring device configured as described above will be explained.

When the object W to be measured is set on the base 13 between the light projecting section 11a and the light receiving section ttb including the deflector 1O, a laser beam is first emitted from the light source 1 in the deflector 1O. This laser light is reflected by the concave surface t18 of the tuning fork vibrator 3 via the mirror 2 while the degree of convergence or divergence of the beam deflected by the lens 6 is adjusted. Further, this laser beam is sinusoidally scanned parallel to the optical axis via the mirror 2 and lens 14 by the vibration of the tuning fork oscillator 3, with the deflection angle maintained sufficiently by the concave mirror 8, and is directed to the object to be measured. irradiated. At this time, a part of the laser beam is reflected by the half mirror 4 and guided to the monitor circuit 5a via the mirror 2, and the vibration of the tuning fork vibrator 3 is controlled based on the result of this monitoring, and the emitted laser beam is A spot rate of the scanning position is performed. Then, when the object to be measured is irradiated with the laser beam, only the laser beam that passes through the object to be measured is received by the light receiver 17 via the lens 15 in the light receiving section 11b. This received light is processed by the processing section 18, and the outer diameter φ of the object W to be measured and the position of the object W in the X direction are calculated.

Figure 4 shows a recorder (
This data shows the deviation state of the outer diameter of the measured object with respect to the movement of the object in the be.

Looking at this data, it can be seen that in the conventional model, the deviation dφ of the outer diameter φ with respect to the movement of the object to be measured is large, whereas in this example, the deviation dψ is extremely small and stable, and as mentioned above, the accuracy is always high. It can be seen that the outer diameter φ of the object to be measured can be measured. Therefore, as mentioned above, the focal length of the lens 14 can be reduced, and the number of mirrors between the tuning fork vibrator 3 and the lens 14 can also be reduced. was realized.

As explained above, according to the deflector 10 of this embodiment, in which the deflection angle θ of the laser beam irradiated onto the object to be measured can be sufficiently determined by the concave mirror 8, the object to be measured can be The distance between each optical component is long to obtain a sufficient deflection angle of the light irradiated onto the object (compared to a conventional deflector, the distance between each optical component can be shortened, The mounting space can be made extremely small, and the device itself can be made compact.Furthermore, the focal length of the lens 14 can be made small, and the number of mirrors between the tuning fork vibrator 3 and the lens 14 can also be made small. Since the deflector can be reduced in number, optical errors can be reduced, and when this deflector is applied to an outer diameter measuring device, highly accurate measurement can be performed.

In addition, in the above-mentioned embodiments, the case where the deflector is applied to an outer diameter measuring device is explained as an example, but the deflector is not limited to this, and other measuring devices such as a thickness gauge of a transparent body or a displacement measuring device using triangulation can be used. For example, taking a thickness gauge as an example, as shown in FIG.
When a laser beam is emitted from the object W, the tuning fork vibrator 3 and the concave mirror 8 scan the object W with this laser beam as a parallel vibration spot having a predetermined deflection angle.
By separating the reflected light from the slit 19 through the slit 19,
A bimodal waveform output is obtained in synchronization with the scanning of the laser beam, and the thickness of the object W to be measured is measured from the peak interval of this signal.

In the figure, the same parts as the components of the deflector of this embodiment are given the same numbers.

[Effects of the Invention] As explained above, according to the deflector of the present invention, stable deflection of a light beam can be obtained with a sufficient number of scans and a sufficient deflection angle. In addition, since the concave mirror provides a sufficient deflection angle, the distance between optical components placed on the optical path can be shortened to the minimum necessary, allowing each component to be placed without requiring a large amount of installation space. This allows the device to be made more compact.

In addition, according to the outer diameter measuring device using the above-mentioned deflector, since the object to be measured is always irradiated with a more stable light beam than the deflector, it is possible to perform highly accurate measurements with extremely little error. Since the deflection angle is large, the focal length of the lens lla can also be made small, and the device can be made more compact.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing an embodiment of the deflector according to the present invention; Fig. 2 is a schematic diagram showing an embodiment of an outer diameter measuring device equipped with the deflector; and Fig. 3 is a schematic diagram showing an embodiment of the deflector. FIG. 4 is a cross-sectional view of an outer diameter measuring device equipped with an outer diameter measuring device according to the present invention, FIG. 6 is a sectional view showing the specific internal structure of a deflector using a tuning fork vibrator, and FIG. 7 is a diagram showing a deflector according to the present invention applied to a thickness gauge. FIG. l... Light source, 3... Tuning fork vibrator, 5... Drive unit,
6-...Lens, 8...Concave mirror, 9...Outer diameter measuring device, 10...Deflector, lla...Light projection part, llb...
... Light receiving section, 18... Processing section.

Claims (1)

[Scope of Claims] 1) A light source, a tuning fork vibrator provided with a concave mirror that emits a light beam from the light source with a predetermined deflection angle, and a tuning fork vibrator provided on an optical path between the tuning fork vibrator and the light source. 1. A deflector comprising: a lens that adjusts convergence and divergence states of a deflected light beam; and a drive section that controls driving of the tuning fork vibrator. 2) The deflector according to claim 1, wherein an aspherical mirror or a cylindrical mirror is used in place of the concave mirror. 3) The deflector according to claim 1, wherein a lens designed to reduce aberrations of the concave mirror is used as the lens. 4) A deflector according to claim 1, a lens for scanning the light flux emitted from the deflector parallel to the optical axis, and a lens for converging the light flux passing from the lens through the object to be measured. , a light receiver that receives the light beam converged by the lens, and a processing section that calculates the outer diameter of the object based on the signal obtained from the light receiver and the signal obtained from the drive section. An outer diameter measuring device characterized by: