JPH08334318A - Apparatus for measuring outer diameter - Google Patents

Abstract

PURPOSE: To make the whole of an apparatus compact by reducing a distance between optical parts on an optical path to a necessary minimum. CONSTITUTION: A light source 1, a tuning fork vibrator 3 for projecting a luminous flux from the light source 1 with a predetermined deflection angle, a driving part for controlling the vibration of the tuning fork vibrator 3, and a lens 14 for scanning the luminous flux from the tuning fork vibrator 3 in parallel to an optical axis and irradiating an object to be measured are encased in a case 7, thereby constituting a light-projecting part 11a. The luminous flux projected from the tuning fork vibrator 3 is made incident into the lens 14 with the deflection angle greatly diffused to be symmetric to the optical axis and larger than twice an angular change due to the bending/vibration of the tuning fork vibrator 3. A lens 15 for converging the luminous flux from the lens 14 and a photodetector 17 for receiving the converged luminous flux are encased in a case 12, thereby to constitute a photodetecting part 11b. The light- projecting part 11a and the photodetecting part 11b are set on a stage 13 although separated a predetermined distance so that the object to be measured can be loaded thereon.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring device for measuring an outer diameter or the like of an object to be measured by using a deflector which deflects light from a light source to a desired angle.

[0002]

2. Description of the Related Art A deflector such as a rotating mirror or a tuning fork deflector is known as a device that outputs a light beam emitted from a light source at a predetermined deflection angle. As an application example, this deflector scans a light beam parallel to the optical axis and irradiates the DUT to calculate the time at which the light beam hits and is shaded by the DUT. It is applied to the measuring outer diameter measuring device.

FIG. 5 shows a schematic structure of a deflector which has been conventionally used as a device for measuring the outer diameter of an object to be measured.

The deflector shown in this drawing is driven by a light source 20 for emitting a laser beam and a motor driver 31, and is a rotation for outputting a laser beam supplied from the light source 20 through a mirror 32 at a predetermined deflection angle θ _2. The mirror 21,
A mirror 22 is provided between the light source 20 and the rotating mirror 21 for allowing the laser light from the light source 20 to enter the rotating mirror 21. The rotating mirror 21 deflects the required laser light. The angle θ ₂ is obtained.

Further, although not shown, the deflector using a tuning fork vibrator in place of the rotary mirror 21 has a plane mirror attached to the tip of the tuning fork vibrator, so that the laser light from the light source is reflected by the mirror. The laser beam is made incident on the plane mirror of the tuning fork vibrator via the plane mirror, and the laser beam deflected at a predetermined angle through the plane mirror is scanned by the vibration of the tuning fork vibrator. Further, a half mirror is arranged on the optical path between the plane mirror and the object to be measured, and the laser beam branched by the half mirror has its amplitude and phase detected by the monitor section of the drive section. The vibration of the tuning fork vibrator is controlled by the drive circuit based on the detection result.

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

That is, the components of the deflector are positioned in the housing 29 with the distance between the components being kept constant, and the laser light emitted from the light source 25 is a tuning fork oscillator. It is reflected by the plane mirror 24 of 23 and guided to the first mirror 26 a via the half mirror 27. At this time, a part of the laser light is reflected by the half mirror 27,
It is guided to the monitor unit 28 via the mirror 26b. The laser light reflected by the mirror 26a is guided to the mirror 26c located in the lower center of the housing 29 and slightly to the right. Further, the laser light reflected by the mirror 26c is guided to a mirror 26d located on the lower left side of the housing 29, and then emitted to the outside through a lens 30 provided so as to face the mirror 26d. It The laser light is scanned parallel to the optical axis of the lens 30 to irradiate the object to be measured. Ask for.

[0008]

However, the above-mentioned conventional deflector and the outer diameter measuring device using this deflector have the following problems.

That is, according to the deflector using the rotating mirror 21 described above, a sufficiently large deflection angle θ ₂ can be obtained, but since the rotating mirror 21 is mechanically driven, this is used as the outer diameter. When applied to a measuring device, the response speed is limited by the processing unit, so that even a high-speed scanning is as low as 400 to 500 times / s or less, and since the scanning is in one direction, the measured object vibrates. However, there is a problem that it is likely to be adversely affected.

Further, in the deflector using the tuning fork vibrator 23 described later, reciprocal scanning of the laser beam is possible, the number of times of scanning described above can be performed 1000 times / s or more, and the object to be measured vibrates. The effect of the case can be reduced. However, the current deflector using the tuning fork vibrator 23 cannot obtain a sufficient deflection angle such that the deflection angle θ is about 150 mrad or less. Further, when the measurement range of the outer diameter measuring machine is set to be large, it is necessary to lengthen the focal length (f) of the lens 14 (fθ lens) to set a large scanning width. Therefore, it is necessary to dispose a plurality of mirrors 26 on the optical path to extend the optical path between the mirror 24 at the tip of the tuning fork vibrator 23 and the lens 14. As a result, the number of parts increases, which causes measurement value errors due to the movement of the DUT in the scanning space due to the effects of mechanical and optical errors caused by multiple mirrors. Had the problem of becoming larger.

Therefore, the present invention has been made in view of the above-mentioned problems, and an object of the present invention is to shorten the distance between optical components arranged on the optical path to a necessary minimum to achieve compactness. At the same time, another object of the present invention is to provide an outer diameter measuring device capable of performing highly accurate measurement with very few errors.

[0012]

In order to achieve the above-mentioned object, the present invention has a light source 1 and a reflecting surface at a tip thereof on which a light beam from the light source is incident symmetrically with respect to an optical axis. The tuning fork vibrator 3 which emits a light beam incident on the beam at a predetermined deflection angle by flexural vibration, the drive unit 5 which controls the vibration of the tuning fork vibrator, and the light beam which is emitted from the reflecting surface of the tuning fork vibrator The second optical member 14 for scanning in parallel to the axis and irradiating the object to be measured W is emitted from the light projecting portion 11a housed in the first casing 7 and the light projecting portion. A light receiving portion 11b in which a third optical component 15 for converging a light beam and a light receiver 17 for receiving the light beam converged by the third optical component are housed in a second housing 12, and the light receiver. The outer diameter of the measured object based on the signal obtained from the above and the signal obtained from the drive unit The light beam emitted from the tuning fork vibrator is provided with a processing unit 18 for calculation, and the deflection angle is diffused symmetrically with respect to the optical axis to be larger than twice the angle change due to the flexural vibration of the tuning fork vibrator. The light is incident on the second optical member, and the light projecting portion and the light receiving portion are integrally provided at a distance that allows the object to be measured to be arranged.

According to the outer diameter measuring device, the light projecting portion 11a
In, the light flux emitted from the light source 1 is incident on the reflection surface of the tuning fork vibrator 3 symmetrically with respect to the optical axis. When the vibration of the tuning fork vibrator 3 is controlled by the driving unit 5, the tuning fork vibrator 3 is controlled.
The light flux emitted from the light source is diffused into the second optical member 14 with the deflection angle being symmetrical with respect to the optical axis and being larger than twice the angle change due to the flexural vibration of the tuning fork vibrator 3. As a result, the deflection angle of the light beam incident on the second optical component 14 is further expanded as compared with the conventional deflection by the tuning fork vibrator. Then, the light beam incident on the second optical component 14 scans in parallel to the optical axis and irradiates the DUT W. The light flux which has passed through the object to be measured W by the irradiation of the light flux is received by the light receiver 17 through the third optical component 15 in the light receiver 11b, and the object to be measured based on the received light and the signal from the drive unit 5. The outer diameter of W is calculated. In this way, since the deflection angle of the light flux emitted from the tuning fork vibrator 3 can be sufficiently enlarged and the object to be measured W can be irradiated with the deflection angle,
The distance between the optical components arranged on the optical path can be shortened to the required minimum, and the focal length of each optical component can also be reduced. Can be realized.

[0014]

1 is a schematic configuration diagram showing an embodiment of a deflector used in an outer diameter measuring apparatus according to the present invention.

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

The light source 1 outputs laser light, which is reflected by the mirror 2 toward the tuning fork vibrator 3 side. At the tip of the tuning fork vibrator 3, concave mirrors 8 are fixedly installed. The concave mirror 8 is for obtaining a deflection angle θ ₁ so that a light beam having a sufficient scanning width is emitted to the object to be measured W. In addition to the concave mirror, for example, a cylindrical or aspherical mirror is used. May be. Then, the light deflected here is reciprocally scanned in a reciprocal manner at the natural frequency of the tuning fork vibrator 3 and transmitted through the lens 14 to be output to the object to be measured W.

Here, since the tuning fork vibrator 3 driven at the natural frequency is used to scan the light beam applied to the object to be measured W, the reciprocal scanning of the laser beam with respect to the object to be measured W is performed. In addition, the tip can be made to have a concave mirror, a cylindrical mirror, or an aspherical mirror so that the deflection angle can be improved five times or more as compared with the conventional tuning fork deflector. Therefore, as described above, the focal length of the lens 14 (fθ lens) can be reduced, and the number of mirrors between the concave mirror 8 and the lens 14 can be reduced, so that an optical error can be reduced. Therefore, highly accurate measurement can be performed.

The half mirror 4 reflects a part of the light from the concave mirror 8, and this reflected light is output to the drive unit 5.

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

The lens 6 disposed on the optical path between the light source 1 and the tuning fork vibrator 3 is combined with the concave mirror 8 of the tuning fork vibrator 3 and the degree of convergence and divergence of laser light deflected by the concave mirror 8. Is being 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 is used.
A light receiving section 11b is installed at a position opposed to the object to be measured W with a light beam passing through the object to be measured W through the optical system. The light is received by the light receiver 17. Then, the processing unit 18
In the process, the signal from the light receiver 17 is processed as the signal from the monitor 5a to calculate the outer diameter value of the object to be measured and the position of the object to be measured in the X direction.

Further, the operation of calculating the outer diameter φ of the object to be measured W in the light receiving portion 11b will be described in detail. The light received through the object to be measured W is photoelectrically converted and then photoelectrically converted. Output to two sample and hold circuits (not shown) controlled by the signal. The sample-hold circuit holds a sinusoidal signal representing the position in the X direction of the scanning light beam generated by the monitor unit 5a in the deflector 10 at a time corresponding to both edges of the measured object W. Further, the difference between the signals from the sample and hold circuits is calculated, and a signal proportional to the outer diameter φ of the object to be measured W is output. This signal is A / D converted and transferred to the processing unit 18, where the outer diameter value φ of the object to be measured W is calculated.

FIG. 3 shows a specific structure of the outer diameter measuring device. Note that the light projecting portion 11a shown in FIG. 3 and the conventional light projecting portion shown in FIG. 6 are shown at substantially the same scale, and as is clear from a comparison of these figures, the present embodiment is realized. The light projecting unit 11a according to the embodiment can shorten the optical path to the minimum, and does not require an installation space even when applied to an outer diameter measuring device, so that the device itself can be made compact.

In the detector 9 of the outer diameter measuring device, the above-mentioned light source 1, mirror 2, tuning fork vibrator 3, half mirror 4, driving unit 5 and lens 6 are positioned and fixed at predetermined distances. The light projecting section 11a and the light receiving section 11b that receives the laser light emitted from the light projecting section 11a and guided through the object to be measured W are respectively configured in separate housings 7 and 12 to form one base. It is fixed on 13 with a predetermined distance.

Next, the operation of the outer diameter measuring device configured as described above will be described. Projector 1 including deflector 10
When the object to be measured W is set on the base 13 between the 1a and the light receiving section 11b, first, the laser light is emitted from the light source 1 in the deflector 10. This laser light is reflected by the concave mirror 8 of the tuning fork vibrator 3 via the mirror 2 while adjusting the degree of convergence or divergence of the beam deflected by the lens 6. Further, this laser beam is sinusoidally scanned by the vibration of the tuning fork vibrator 3 through the mirror 2 and the lens 14 in a state where the deflection angle θ ₁ is sufficiently maintained by the concave mirror 8 and is parallel to the optical axis. Is irradiated. At this time, a part of the laser light 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 by the result of this monitor.
The scanning position of the emitted laser light is simulated. Then, only the laser light passing through the object to be measured is received by the light receiver 17 via the lens 15 in the light receiving section 11b. The received light is processed by the processing unit 18, and the outer diameter φ of the measured object W and the position of the measured object W in the X direction are calculated.

FIG. 4 shows the X of the object to be measured recorded by a recorder (not shown) in order to evaluate the performance of the outer diameter measuring machine.
It is data showing the deviation state of the outer diameter with respect to the movement in the direction, and is compared with the conventional outer diameter measuring device using the deflector shown in FIG.

Looking at this data, in the conventional case, the deviation dφ of the outer diameter φ with respect to the movement of the object to be measured is large, whereas in the case of the present embodiment, the deviation dφ is extremely small and stable. It can be seen that the outer diameter φ of the object to be measured can always be measured with high accuracy. Therefore, as described 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 be reduced, so that an optical error can be reduced and high precision can be achieved. It was realized.

As described above, according to the deflector 10 of this embodiment in which the deflection angle θ _{1 of the} laser beam applied to the object to be measured can be sufficiently taken by the concave mirror 8, the deflector 10 shown in FIGS.
It is possible to reduce the distance between the optical components as compared with the conventional deflector in which the distance between the optical components is set to be long in order to sufficiently obtain the deflection angle of the light irradiated on the object to be measured as shown in FIG. Therefore, the mounting space for each component can be made extremely small, and the device itself can be made compact. Further, since 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 be made small, an optical error can be reduced, and this deflector can have an outer diameter. When applied to a measuring device, highly accurate measurement can be performed.

Further, in the above-described embodiment, the case where the deflector is applied to the outer diameter measuring device has been described as an example, but the present invention is not limited to this, and other measuring instruments such as a transparent body thickness gauge and triangulation are used. It may be applied to the displacement measuring device described above. For example, taking a thickness meter as an example, when laser light is emitted from the light source 1 as shown in FIG. 7, this laser light is covered by the tuning fork vibrator 3 and the concave mirror 8 as parallel vibration spots having a predetermined deflection angle. The measurement object W is scanned, and the reflected light from the measurement object W can be separated through the slit 19, and a bimodal waveform output can be obtained in synchronization with the scanning of the laser light. Thing W
Is measured. In the figure, the same parts as those of the deflector according to the present embodiment are designated by the same reference numerals.

[0031]

As described above, according to the outer diameter measuring apparatus of the present invention, stable light beam deflection can be obtained with a sufficient number of scans and deflection angles in the light projecting section. Further, since a sufficient deflection angle can be obtained in the light projecting unit, the distance between the optical components arranged on the optical path can be shortened to the necessary minimum, and the focal length of each optical component can be shortened, so that the installation space can be reduced. It is possible to reduce the size of the entire apparatus by arranging each component without requiring many.
Moreover, since a stable light flux is always emitted from the light projecting unit to the object to be measured, highly accurate measurement with very few errors can be performed.

[Brief description of drawings]

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

FIG. 2 is a schematic configuration diagram showing an embodiment of an outer diameter measuring device including the deflector.

FIG. 3 is a sectional view of an outer diameter measuring device including the deflector.

FIG. 4 is data showing the deviation state of the outer diameter with respect to the moving amount of the measured object recorded by the recorder in the outer diameter measuring apparatus of the present invention.

FIG. 5 is a diagram showing a schematic configuration of a conventional deflector using a rotating mirror.

FIG. 6 is a cross-sectional view showing a specific internal configuration of a deflector including a tuning fork vibrator.

FIG. 7 is a configuration diagram when a deflector according to the present invention is applied to a thickness gauge.

[Explanation of symbols]

1 ... Light source, 3 ... Tuning fork vibrator, 5 ... Driving unit, 6 ... Lens,
8 ... concave mirror, 9 ... outer diameter measuring device, 10 ... deflector, 11a
... light emitting unit, 11b ... light receiving unit, 18 ... processing unit.

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[Procedure amendment]

[Submission date] June 6, 1996

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

[Outer diameter measuring device]

[Claims]

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an outer diameter measuring device for measuring the outer diameter of an object to be measured using a deflector that deflects light from a light source to a desired angle.

[0002]

2. Description of the Related Art A deflector such as a rotating mirror or a tuning fork deflector is known as a device that outputs a light beam emitted from a light source at a predetermined deflection angle. As an application example, this deflector scans a light beam parallel to the optical axis and irradiates the DUT to calculate the time at which the light beam hits and is shaded by the DUT. It is applied to the measuring outer diameter measuring device.

FIG. 5 shows a schematic structure of a deflector which has been conventionally used as a device for measuring the outer diameter of an object to be measured.

The deflector shown in this drawing is driven by a light source 20 for emitting a laser beam and a motor driver 31, and is a rotation for outputting a laser beam supplied from the light source 20 through a mirror 32 at a predetermined deflection angle θ _2. The mirror 21,
A mirror 22 is provided between the light source 20 and the rotating mirror 21 for allowing the laser light from the light source 20 to enter the rotating mirror 21. The rotating mirror 21 deflects the required laser light. The angle θ ₂ is obtained.

Further, although not shown, the deflector using a tuning fork vibrator in place of the rotary mirror 21 has a plane mirror attached to the tip of the tuning fork vibrator, so that the laser light from the light source is reflected by the mirror. The laser beam is made incident on the plane mirror of the tuning fork vibrator via the plane mirror, and the laser beam deflected at a predetermined angle through the plane mirror is scanned by the vibration of the tuning fork vibrator. Further, a half mirror is arranged on the optical path between the plane mirror and the object to be measured, and the laser beam branched by the half mirror has its amplitude and phase detected by the monitor section of the drive section. The vibration of the tuning fork vibrator is controlled by the drive circuit based on the detection result.

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

That is, the components of the deflector are positioned in the housing 29 with the distance between the components being kept constant, and the laser light emitted from the light source 25 is a tuning fork oscillator. It is reflected by the plane mirror 24 of 23 and guided to the first mirror 26 a via the half mirror 27. At this time, a part of the laser light is reflected by the half mirror 27,
It is guided to the monitor unit 28 via the mirror 26b. The laser light reflected by the mirror 26a is guided to the mirror 26c located in the lower center of the housing 29 and slightly to the right. Further, the laser light reflected by the mirror 26c is guided to a mirror 26d located on the lower left side of the housing 29, and then emitted to the outside through a lens 30 provided so as to face the mirror 26d. It The laser light is scanned parallel to the optical axis of the lens 30 to irradiate the object to be measured. Ask for.

[0008]

However, the above-mentioned conventional deflector and the outer diameter measuring device using this deflector have the following problems.

That is, according to the deflector using the rotating mirror 21 described above, a sufficiently large deflection angle θ ₂ can be obtained, but since the rotating mirror 21 is mechanically driven, this is used as the outer diameter. When applied to a measuring device, the response speed is limited by the processing unit, so that even a high-speed scanning is as low as 400 to 500 times / s or less, and since the scanning is in one direction, the measured object vibrates. However, there is a problem that it is likely to be adversely affected.

Further, in the deflector using the tuning fork vibrator 23 described later, reciprocal scanning of the laser beam is possible, the number of times of scanning described above can be performed 1000 times / s or more, and the object to be measured vibrates. In this case, the influence can be reduced. However, the current deflector using the tuning fork vibrator 23 cannot obtain a sufficient deflection angle such that the deflection angle θ is about 150 mrad or less. Further, when the measurement range of the outer diameter measuring machine is set to be large, it is necessary to lengthen the focal length (f) of the lens 14 (fθ lens) to set a large scanning width. Therefore, it is necessary to dispose a plurality of mirrors 26 on the optical path to extend the optical path between the mirror 24 at the tip of the tuning fork vibrator 23 and the lens 14. As a result, the number of parts increases, which causes measurement value errors due to the movement of the DUT in the scanning space due to the effects of mechanical and optical errors caused by multiple mirrors. Had the problem of becoming larger.

Therefore, the present invention has been made in view of the above-mentioned problems, and an object of the present invention is to shorten the distance between optical components arranged on the optical path to a necessary minimum to achieve compactness. At the same time, another object of the present invention is to provide an outer diameter measuring device capable of performing highly accurate measurement with very few errors.

[0012]

In order to achieve the above object, the outer diameter measuring apparatus according to the present invention has a first accommodating portion 7 and a second accommodating portion 12 which are spaced apart from each other so that an object to be measured W can be interposed. Are opposed to each other to form a housing, and the first housing portion has a light source 1 and a reflection surface at a tip thereof on which a light beam from the light source is incident symmetrically with respect to an optical axis. A tuning fork vibrator 3 that emits a light beam incident on a reflecting surface at a predetermined deflection angle by flexural vibration, and is provided on an optical path between the tuning fork vibrator and the light source and is deflected by the reflecting surface of the tuning fork vibrator. First lens 6 for adjusting the state of convergence and divergence of the reflected light beam
A driving unit 5 for controlling the vibration of the tuning fork vibrator; a half mirror 4 for reflecting a part of the light beam emitted from the tuning fork vibrator to the driving unit as a monitor signal; A second lens 14 for scanning the object to be measured by scanning in parallel with respect to the light source, and a light beam from the tuning fork vibrator provided on the optical path between the second lens 14 and the tuning fork vibrator. And a mirror 2 for reflecting the light on the second lens. The light flux emitted from the tuning fork vibrator has a deflection angle symmetrical with respect to the optical axis and changes in angle due to flexural vibration of the tuning fork vibrator. It is adapted to be incident on the mirror after being diffused more than twice.
A third lens 15 provided in parallel with the second lens for converging the scanning light flux, and the light flux converged by the third lens is received and converted into an electric signal. It is characterized in that the light receiver 17 is housed therein.

According to the above outer diameter measuring device, the light beam emitted from the light source 1 is incident on the center line of the flexural vibration of the tuning fork vibrator 3. At that time, the tuning fork vibrator 3 is moved by the first lens 6 provided on the optical path between the tuning fork vibrator 3 and the light source 1.
The state of convergence and divergence of the light flux deflected by the reflection surface of is adjusted. When the vibration of the tuning fork vibrator 3 is controlled by the driving unit 5, the luminous flux emitted from the tuning fork vibrator 3 is diffused so as to be larger than twice the angular change of the flexural vibration of the tuning fork vibrator 3, and then the second Is incident on the lens 14. As a result, the deflection angle of the light beam incident on the second lens 14 is
It is further expanded than the conventional deflection by the tuning fork vibrator. At this time, a part of the light flux emitted from the tuning fork vibrator 3 is reflected by the half mirror 4 as a monitor signal to the drive unit 5. Then, the light beam incident on the second lens 14 scans in parallel with the optical axis and irradiates the DUT W. The light flux which has passed through the object to be measured W by the irradiation of the light flux is received by the light receiver 17 through the third lens 15 and converted into an electric signal. Based on the electric signal by this light reception and the signal from the drive unit 5. Then, the outer diameter of the object to be measured W is calculated. In this way, the deflection angle of the luminous flux emitted from the tuning fork vibrator 3 can be sufficiently expanded to irradiate the DUT W, so that the distance between the optical components arranged on the optical path can be minimized. The focal length of each optical component can be shortened as well as being shortened. Then, an optical component for irradiating the object to be measured W with the scanning light flux is housed in the first housing part 7, and the object to be measured W is measured.
An optical component for receiving a light flux passing through the outer diameter and calculating the outer diameter thereof is housed in the second housing portion 12, and the DUT W is separated so as to intervene between the first housing portion 7 and the second housing portion. By arranging the parts 12 so as to face each other to form a housing, it is possible to arrange each component and reduce the size of the entire device without requiring a large installation space.

[0014]

1 is a schematic configuration diagram showing an embodiment of a deflector used in an outer diameter measuring apparatus according to the present invention.

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

The light source 1 outputs laser light, which is reflected by the mirror 2 toward the tuning fork vibrator 3 side.
It is incident on the center line of the flexural vibration of the tuning fork vibrator 3. At the tip of the tuning fork vibrator 3, concave mirrors 8 are fixedly installed. As shown in FIG. 1, the concave mirror 8 has a tuning fork vibrator 3
Are arranged so that the deviation of the deflection point in the optical axis direction is symmetric with respect to the optical axis. The concave mirror 8 diffuses the light so as to be larger than twice the angular change of the flexural vibration of the tuning fork vibrator 3, and obtains a deflection angle θ ₁ so that a light beam having a sufficient scanning width is emitted to the object to be measured W. ing. In addition to the concave mirror, for example, a mirror formed in a cylindrical shape or an aspherical shape may be used. Then, the light deflected here is reciprocally scanned in a reciprocal manner at the natural frequency of the tuning fork vibrator 3 and transmitted through the lens 14 to be output to the object to be measured W.

Here, since the tuning fork vibrator 3 driven at the natural frequency is used to scan the light beam applied to the object to be measured W, the reciprocal scanning of the laser beam with respect to the object to be measured W is performed. In addition, the tip can be made to have a concave mirror, a cylindrical mirror, or an aspherical mirror so that the deflection angle can be improved five times or more as compared with the conventional tuning fork deflector. Therefore, as described above, the focal length of the lens 14 (fθ lens) can be reduced, and the number of mirrors between the concave mirror 8 and the lens 14 can be reduced, so that an optical error can be reduced. Therefore, highly accurate measurement can be performed.

The half mirror 4 reflects a part of the light from the concave mirror 8, and this reflected light is output to the drive unit 5.

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

The lens 6 disposed on the optical path between the light source 1 and the tuning fork vibrator 3 is combined with the concave mirror 8 of the tuning fork vibrator 3 and the degree of convergence and divergence of laser light deflected by the concave mirror 8. Is being 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 is used.
A light receiving section 11b is installed at a position opposed to the object to be measured W with a light beam passing through the object to be measured W through the optical system. The light is received by the light receiver 17. Then, the processing unit 18
In this case, the signal from the light receiver 17 and the signal from the monitor unit 5a are processed to calculate the outer diameter value of the measured object and the position of the measured object in the X direction.

Further, the operation of calculating the outer diameter φ of the object to be measured W in the light receiving portion 11b will be described in detail. The light received through the object to be measured W is photoelectrically converted and then photoelectrically converted. Output to two sample and hold circuits (not shown) controlled by the signal. The sample-hold circuit holds a sinusoidal signal representing the position in the X direction of the scanning light beam generated by the monitor unit 5a of the deflector 10 at a time corresponding to both edges of the object to be measured W. Further, the difference between the signals from the sample and hold circuits is calculated, and a signal proportional to the outer diameter φ of the object to be measured W is output. This signal is A / D converted and transferred to the processing unit 18, where the outer diameter value φ of the object to be measured W is calculated.

FIG. 3 shows a specific structure of the outer diameter measuring device. Note that the light projecting portion 11a shown in FIG. 3 and the conventional light projecting portion shown in FIG. 6 are shown at substantially the same scale, and as is clear from a comparison of these figures, the present embodiment is realized. The light projecting unit 11a according to the embodiment can shorten the optical path to the minimum, and does not require an installation space even when applied to an outer diameter measuring device, so that the device itself can be made compact.

In the detector 9 of the outer diameter measuring device, the above-mentioned light source 1, mirror 2, tuning fork vibrator 3, half mirror 4, driving unit 5 and lens 6 are positioned and fixed at predetermined distances. The light projecting section 11a and the light receiving section 11b that receives the laser light emitted from the light projecting section 11a and guided through the object to be measured W are respectively configured in separate housings 7 and 12 to form one base. It is fixed on 13 with a predetermined distance.

Next, the operation of the outer diameter measuring device configured as described above will be described. Projector 1 including deflector 10
When the object to be measured W is set on the base 13 between the 1a and the light receiving section 11b, first, the laser light is emitted from the light source 1 in the deflector 10. This laser light is reflected by the concave mirror 8 of the tuning fork vibrator 3 via the mirror 2 while adjusting the degree of convergence or divergence of the beam deflected by the lens 6. Further, this laser light is sinusoidally generated by the vibration of the tuning fork vibrator 3 while the deflection angle θ ₁ (greater than twice the angular change of the flexural vibration of the tuning fork vibrator 3) is sufficiently maintained by the concave mirror 8. Mirror 2 and lens 1
The object to be measured is scanned through 4 through the optical axis in parallel with the optical axis. At this time, a part of the laser light 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 by the result of this monitor, and the laser light emitted is The scanning position is simulated. Then, only the laser beam that passes through the object to be measured has the lens 15 in the light receiving section 11b.
The light is received by the light receiver 17 via. The received light is processed by the processing unit 18, and the outer diameter φ of the measured object W and the position of the measured object W in the X direction are calculated.

FIG. 4 shows the X of the object to be measured recorded by a recorder (not shown) in order to evaluate the performance of the outer diameter measuring machine.
It is data showing the deviation state of the outer diameter with respect to the movement in the direction, and is compared with the conventional outer diameter measuring device using the deflector shown in FIG.

Looking at this data, in the conventional case, the deviation dφ of the outer diameter φ with respect to the movement of the object to be measured is large, whereas in the case of the present embodiment, the deviation dφ is extremely small and stable. It can be seen that the outer diameter φ of the object to be measured can always be measured with high accuracy. Therefore, as described 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 be reduced, so that an optical error can be reduced and high precision can be achieved. It was realized.

As described above, according to the deflector 10 of this embodiment in which the deflection angle θ _{1 of the} laser beam applied to the object to be measured can be sufficiently taken by the concave mirror 8, the deflector 10 shown in FIGS.
It is possible to reduce the distance between the optical components as compared with the conventional deflector in which the distance between the optical components is set to be long in order to sufficiently obtain the deflection angle of the light irradiated on the object to be measured as shown in FIG. Therefore, the mounting space for each component can be made extremely small, and the device itself can be made compact. Further, since 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 be made small, an optical error can be reduced, and this deflector can have an outer diameter. When applied to a measuring device, highly accurate measurement can be performed.

Further, in the above-described embodiment, the case where the deflector is applied to the outer diameter measuring device has been described as an example, but the present invention is not limited to this, and other measuring instruments such as a transparent body thickness gauge and triangulation are used. It may be applied to the displacement measuring device described above. For example, taking a thickness meter as an example, when laser light is emitted from the light source 1 as shown in FIG. 7, this laser light is covered by the tuning fork vibrator 3 and the concave mirror 8 as parallel vibration spots having a predetermined deflection angle. The measurement object W is scanned, and the reflected light from the measurement object W can be separated through the slit 19, and a bimodal waveform output can be obtained in synchronization with the scanning of the laser light. Thing W
Is measured. In the figure, the same parts as those of the deflector according to the present embodiment are designated by the same reference numerals.

[0031]

As described above, according to the outer diameter measuring apparatus of the present invention, stable light beam deflection can be obtained with a sufficient number of scans and deflection angles in the light projecting section. Further, since a sufficient deflection angle can be obtained in the light projecting unit, the distance between the optical components arranged on the optical path can be shortened to the necessary minimum, and the focal length of each optical component can be shortened, so that the installation space can be reduced. It is possible to reduce the size of the entire apparatus by arranging each component without requiring many.
Moreover, since a stable light flux is always emitted from the light projecting unit to the object to be measured, highly accurate measurement with very few errors can be performed.

[Brief description of drawings]

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

FIG. 2 is a schematic configuration diagram showing an embodiment of an outer diameter measuring device including the deflector.

FIG. 3 is a sectional view of an outer diameter measuring device including the deflector.

FIG. 4 is data showing the deviation state of the outer diameter with respect to the moving amount of the measured object recorded by the recorder in the outer diameter measuring apparatus of the present invention.

FIG. 5 is a diagram showing a schematic configuration of a conventional deflector using a rotating mirror.

FIG. 6 is a cross-sectional view showing a specific internal configuration of a deflector including a tuning fork vibrator.

FIG. 7 is a configuration diagram when a deflector according to the present invention is applied to a thickness gauge.

[Explanation of Codes] 1 ... Light source, 3 ... Tuning fork oscillator, 5 ... Driving unit, 6 ... Lens,
8 ... concave mirror, 9 ... outer diameter measuring device, 10 ... deflector, 11a
... light emitting unit, 11b ... light receiving unit, 18 ... processing unit.

Front page continuation (72) Inventor Takahiro Nakamura 5-10-10 Minamiazabu, Minato-ku, Tokyo Anritsu Co., Ltd.

Claims (1)

[Claims] 1. A light source (1) and a reflection surface at the tip of which a light beam from the light source is incident symmetrically with respect to the optical axis, and the light beam incident on the reflection surface is deflected at a predetermined deflection angle by flexural vibration. With a tuning fork vibrator (3), a drive unit (5) for controlling the vibration of the tuning fork vibrator, and a light beam emitted from the reflecting surface of the tuning fork vibrator, which is scanned parallel to the optical axis. A light projecting portion (11a) in which a second optical member (14) for irradiating a measurement object (W) is housed in a first housing (7), and a light beam emitted from the light projecting portion. A third optical component (15) for converging the light and a light receiver (17) for receiving the light flux converged by the third optical component are housed in a second housing (12). 11b), and the outer diameter of the object to be measured is calculated based on the signal obtained from the light receiver and the signal obtained from the driving unit. The light flux emitted from the tuning fork vibrator is diffused symmetrically with respect to the optical axis with respect to the angle change due to the flexural vibration of the tuning fork vibrator. The light is incident on the second optical member, and the light projecting unit and the light receiving unit are integrally provided at a distance allowing the object to be measured to be arranged. Outer diameter measuring device.