JP4616692B2 - Displacement detector - Google Patents

Description

  The present invention relates to a displacement detection device. More specifically, the present invention relates to a displacement detection apparatus that detects a displacement of a workpiece using a speckle image generated by interference of scattered light from the workpiece.

Displacement detection devices that detect minute displacement of a workpiece using a speckle image are known (Non-Patent Documents 1 to 4).
FIG. 30 is a diagram illustrating a configuration of a conventional displacement detection device 10.
The displacement detection apparatus 10 includes a casing 11 having a storage space 12 therein, an illumination optical system 13 that irradiates the workpiece W with laser light, and a speckle image generated by interference of scattered light from the workpiece W. A CCD camera 16 that captures an image and an image processing unit 19 that performs image processing on an output image from the CCD camera 16 are provided.
The illumination optical system 13 includes a laser light source 14 and a collimator lens 15, and irradiates the workpiece W with a laser beam from an oblique direction.

Further, between the workpiece W and the CCD camera 16, a magnifying lens 17 that magnifies an image of light scattered on the workpiece surface S toward the CCD camera 16, and between the magnifying lens 17 and the CCD camera 16. The magnifying lens 17, the aperture 18, and the CCD camera 16 are disposed so as to have an optical axis in a direction substantially perpendicular to the workpiece W.
The workpiece W and the displacement detection device 10 can be relatively moved in a direction orthogonal to the normal line of the workpiece W, and the displacement detection device 10 is a displacement amount of the workpiece W in a direction orthogonal to the normal line of the workpiece W. Is detected.
The surface S of the work W is an optically rough surface (optical rough surface), and a speckle image having a black and white spot pattern as shown in FIG. 31 is formed by scattered light from the work W.

  In such a configuration, the light L40 emitted from the laser light source 14 is collimated by the collimator lens 15 and is irradiated onto the workpiece W. Then, the 0th-order light L41 of the light reflected by the workpiece surface S is reflected to the side opposite to the incident direction of the laser light. On the other hand, the scattered light L42 scattered in the direction perpendicular to the workpiece W by the optical rough surface of the workpiece W enters the magnifying lens 17 and is received by the CCD camera 16 through the aperture 18 (L43). Then, a speckle image is picked up by the CCD camera 16.

  Here, a speckle image is picked up at the standard position of the workpiece W, and is stored in the image processing unit 19 as a reference speckle image. Next, the current speckle image when the workpiece W is slightly displaced is captured and output to the image processing unit 19. Then, the current speckle image and the reference speckle image are compared in the image processing unit 19, and the displacement amount of the workpiece W is detected based on the displacement of the pattern to be matched in the image.

The displacement detection device 10 using such a speckle image can detect the displacement of the workpiece W with high resolution with a simple configuration.
Further, by irradiating the laser light L40 from the oblique direction of the workpiece W, the zero-order reflected light L41 is deflected from the magnifying lens 17, and only the scattered light L42 that generates a speckle image is passed through the magnifying lens 17 to the CCD camera 16. It is made to enter. Thereby, a speckle image with a favorable SN ratio can be acquired.

"Optical applied machine measurement technology" 3rd printing, Asakura Shoten, p101-p102 "Applied optics-Introduction to optical measurement-" 4th printing, Maruzen, p152-p153 "Nikkei Advanced Technology 69" Nikkei Inc., Nikkei Industrial Consumption Research Institute, p7-p8 "Optical Measurement Symposium 2004 Proceedings", Optical Measurement Symposium Executive Committee, p75-p77

However, when the laser beam L40 is applied to the workpiece W from an oblique direction, the following problem occurs.
For example, when the workpiece W is displaced in the normal direction and the gap between the displacement detection device 10 and the workpiece W changes, the position on the workpiece surface S where the laser beam L40 strikes is different. This relationship is schematically shown in FIG.
When the position where the laser beam L40 strikes on the workpiece W changes, the speckle image changes. Therefore, when the workpiece W is displaced in the normal direction, even if the workpiece W is not displaced in the direction orthogonal to the normal line, the displacement detection device 10 can use the normal line of the workpiece W based on the change in the speckle image. A displacement in a direction perpendicular to the direction is erroneously detected. Further, when the workpiece W is displaced in the normal direction, the irradiation position of the laser light L40 is different, so that the light amount distribution with respect to the optical axis of the CCD camera 16 is shifted, and the amount of light incident on the CCD camera 16 is insufficient. There also arises a problem that the detection accuracy is lowered.

  It is also known that when the temperature of the laser light source 14 changes, the wavelength of the emitted laser light L40 changes. For example, a change of about 657 ± 0.2 nm occurs. FIG. 33 is a diagram showing how the optical path of the interference light changes when the wavelength of the laser beam L40 changes. When the wavelength of the laser beam L40 changes, the interference position of the light shifts as shown in FIG. 33. Therefore, even if the workpiece W is not displaced, the speckle image captured by the CCD camera 16 is displaced. There arises a problem that the displacement of the workpiece W is erroneously detected.

  An object of the present invention is to provide a displacement detection device that detects a relative displacement with respect to a workpiece with high accuracy without being affected by a gap variation with the workpiece or a temperature change.

The displacement detection apparatus of the present invention includes an illumination optical system that irradiates laser light toward the workpiece surface, and an imaging unit that captures a speckle image generated by light scattered on the workpiece surface. A displacement detection device that detects a relative displacement amount of a workpiece in a direction substantially orthogonal to a normal line of the workpiece based on a change in the speckle image, wherein the illumination optical system is substantially The laser beam is irradiated vertically, the imaging means receives light scattered in a substantially vertical direction of the workpiece surface, and the displacement detection device is a beam disposed on the normal line of the workpiece surface. A splitter, a magnifying lens that is disposed between the workpiece and the imaging unit and that magnifies an image of light scattered on the workpiece surface toward the imaging unit, and between the magnifying lens and the imaging unit In An aperture disposed at a focal position of the magnifying lens, and the beam splitter is disposed between the magnifying lens and the work, and allows light incident from the illumination optical system to be incident on the work surface. The workpiece is irradiated with the laser light reflected in a direction substantially perpendicular to the workpiece, and the light scattered from the workpiece surface is transmitted toward the imaging means. The aperture is formed on the workpiece surface. The vertically reflected light is shielded and the light deviated from the normal line of the workpiece surface is transmitted toward the imaging means .

In such a configuration, the light from the illumination optical system is irradiated substantially perpendicularly to the surface of the workpiece. Then, the reflected light from the workpiece surface is received by the imaging means. At this time, a speckle image is generated by the light reflected on the workpiece surface, and the imaging means captures the speckle image.
The relative displacement of the workpiece is obtained by comparing the speckle image acquired when the workpiece is at the reference position and the speckle image acquired when the workpiece is relatively displaced in a direction substantially orthogonal to the normal direction. Is detected.

According to such a configuration, even when the workpiece moves in the normal direction, the light from the illumination optical system is irradiated substantially perpendicularly to the workpiece surface, so that the light irradiation position does not deviate on the workpiece surface. . Therefore, even if the work moves in the normal direction, the speckle image picked up by the image pickup means does not change, and the amount of reflected light from the work does not change.
For example, when the light is irradiated obliquely with respect to the workpiece surface as in the prior art, when the workpiece fluctuates in the normal direction, the position where the light is irradiated on the workpiece surface is shifted. As a result, the speckle image picked up by the image pickup means fluctuates and the workpiece is in the normal direction even though the object is to detect the workpiece displacement in the direction orthogonal to the normal of the workpiece. The displacement of the workpiece was erroneously detected just by changing.

Further, when the light irradiation position is shifted due to the variation in the normal direction of the workpiece, the light amount distribution of the reflected light is changed, so that the position where a good reflected light amount is obtained is changed. As a result, the amount of light received by the imaging means is insufficient, and the detection accuracy is reduced.
In this regard, in the present invention, light is irradiated onto the workpiece surface from a substantially vertical direction, so that even if the workpiece fluctuates in the normal direction, the light irradiation position does not shift. Therefore, it is possible to accurately detect the displacement in the direction substantially perpendicular to the normal direction of the workpiece regardless of the variation in the normal direction of the workpiece.

  Even if the wavelength of the laser beam fluctuates due to temperature changes, the light is incident on the workpiece substantially perpendicularly, and the light reflected in the vertical direction from the workpiece is received by the imaging means. The position does not change, and the workpiece displacement can be detected with high accuracy.

In this configuration, the light emitted from the illumination optical system is incident on the beam splitter, and a part of the incident light is reflected by the beam splitter and irradiated to the workpiece substantially perpendicularly.
Then, after the light reflected by the workpiece enters the beam splitter, a part of the light passes through the beam splitter and is received by the imaging means.
According to such a configuration, the incident light to the workpiece and the reflected light from the workpiece pass through the beam splitter through the same path between the workpiece and the beam splitter, and light is substantially perpendicular to the workpiece. And the light reflected from the workpiece in the substantially vertical direction is received by the imaging means.

Further, according to this configuration, since there are no parts between the beam splitter and the workpiece, there is no internal reflection between the beam splitter and the workpiece. Therefore, since almost all of the light incident on the beam splitter from the illumination optical system and reflected by the beam splitter toward the workpiece is irradiated onto the workpiece, the amount of light irradiated to the workpiece can be increased. As a result, the amount of light received by the imaging means can be increased, and the detection accuracy can be improved with a clear speckle image.
Moreover, the said aperture is an eccentric aperture, Comprising: The structure which has a light transmissive part in the position shifted | deviated from the optical axis which connects the said imaging means and the said workpiece | work is mentioned as an example. The light transmission part may be a circular small hole provided at a position shifted from the optical axis, or may be a transmission part provided in an annular shape around the optical axis.
In such a configuration, the laser light emitted from the illumination optical system is irradiated substantially perpendicularly onto the workpiece surface via the polarization beam splitter. Then, the light reflected on the workpiece surface is received by the imaging means via the magnifying lens and the aperture. At this time, of the light reflected from the workpiece surface, the light reflected perpendicularly from the workpiece surface is shielded by the aperture when it is focused to the focal position by the magnifying lens and does not enter the imaging means. On the other hand, of the light reflected on the workpiece surface, the light scattered in the direction deviated from the normal direction of the workpiece surface is transmitted through the aperture and imaged by the imaging means.
Of the light reflected from the workpiece surface, the speckle image is generated by the light scattered by the workpiece surface. The light reflected from the workpiece surface vertically (0th order light) is generated as a speckle image. Therefore, when the 0th order light is incident on the image pickup means, the SN ratio of the speckle image is deteriorated.
In this regard, in the present invention, the aperture shields the zero-order light reflected perpendicularly on the workpiece surface and transmits only the scattered light contributing to the generation of the speckle image toward the imaging unit. And clear speckle images can be taken.
By irradiating a laser beam substantially perpendicular to the workpiece surface and imaging light reflected from the workpiece surface in a substantially vertical direction, it is not affected by fluctuations in the normal direction of the workpiece or fluctuations in the wavelength of the laser beam. A displacement in a direction substantially perpendicular to the normal direction of the workpiece can be accurately detected. On the other hand, if the 0th-order light reflected perpendicularly from the workpiece surface also enters the imaging means, it becomes noise for the generation of the speckle image, and there is a possibility that the detection accuracy is lowered. In this respect, in the present invention, since the light reflected perpendicularly from the workpiece surface is shielded by the aperture, a speckle image with a good SN ratio can be obtained.

The displacement detection apparatus of the present invention includes an illumination optical system that irradiates laser light toward the workpiece surface, and an imaging unit that captures a speckle image generated by light scattered on the workpiece surface. A displacement detection device that detects a relative displacement amount of a workpiece in a direction substantially orthogonal to a normal line of the workpiece based on a change in the speckle image, wherein the illumination optical system is substantially The laser beam is irradiated vertically, the imaging means receives light scattered in a substantially vertical direction of the workpiece surface, and the displacement detection device is a beam disposed on the normal line of the workpiece surface. splitter and the enlargement lens to the image formed by light scattered by arranged to the work surface between the workpiece and the imaging means to expand toward the imaging means, and said image pickup means and the magnifying lens Before And a aperture disposed at the focal position of the magnifying lens, the beam splitter is disposed between said aperture and said magnifying lens, the light incident from the illumination optical system relative to the workpiece surface The laser beam is reflected in a substantially vertical direction to irradiate the workpiece with the laser beam, and the light scattered from the workpiece surface is transmitted toward the imaging means, and the aperture is perpendicular to the workpiece surface. The light reflected on the surface of the workpiece is shielded, and the light deviated from the normal line of the workpiece surface is transmitted toward the imaging means.

According to this configuration , the following operations and effects are achieved in addition to the operations and effects substantially the same as those of the displacement detection device described above.
That is, since the beam splitter is disposed on the imaging means side with respect to the magnifying lens, no components are disposed between the magnifying lens and the workpiece. Accordingly, the distance between the magnifying lens and the workpiece can be made closer. As a result, a magnifying lens with a short focal length can be used, and the magnification of the magnifying lens can be increased. The distance between the magnifying lens and the workpiece is about 4.5 mm, which is relatively narrow. Compared to the case where an optical component such as a beam splitter is disposed at this interval, the beam splitter is disposed between the aperture and the magnifying lens. Since it is simpler to arrange, the assembly cost can be reduced.
Further, the aperture is disposed at the focal position of the magnifying lens. By arranging the beam splitter between the magnifying lens and the aperture, the beam splitter is located at a place that has been present as a space in the displacement detector from the beginning. Therefore, the dead space can be eliminated and the displacement detecting device can be made thinner.

The displacement detection apparatus of the present invention includes an illumination optical system that irradiates laser light toward the workpiece surface, and an imaging unit that captures a speckle image generated by light scattered on the workpiece surface. A displacement detection device that detects a relative displacement amount of a workpiece in a direction substantially orthogonal to a normal line of the workpiece based on a change in the speckle image, wherein the illumination optical system is substantially The laser beam is irradiated vertically, the imaging means receives light scattered in a substantially vertical direction of the workpiece surface, and the displacement detection device is a beam disposed on the normal line of the workpiece surface. splitter and the enlargement lens to the image formed by light scattered by arranged to the work surface between the workpiece and the imaging means to expand toward the imaging means, and said image pickup means and the magnifying lens Before And a aperture disposed at the focal position of the magnifying lens, the beam splitter is disposed between the aperture and the imaging means, the light incident from the illumination optical system relative to the workpiece surface The laser beam is reflected in a substantially vertical direction to irradiate the workpiece with the laser beam, and the light scattered from the workpiece surface is transmitted toward the imaging means, and the aperture is perpendicular to the workpiece surface. The light reflected on the surface of the workpiece is shielded, and the light deviated from the normal line of the workpiece surface is transmitted toward the imaging means.

According to such a configuration , the following operations and effects are exhibited in addition to the operations and effects substantially the same as those of the displacement detection device described above.
In other words, since the beam splitter is disposed between the aperture and the imaging means, the beam splitter is disposed at a place that has existed as a space in the displacement detection device from the beginning. Thus, the displacement detection device can be thinned. Since the distance between the aperture and the imaging means is relatively wide in order to increase the magnification by the magnifying lens, it is easy to dispose a beam splitter between the aperture and the imaging means, and the assembly cost is reduced. Can be reduced.
Also, for example, when a beam splitter is disposed between the magnifying lens and the work, a lens having a long focal length must be used because the distance between the magnifying lens and the work cannot be shortened. It was difficult to increase the magnification. In this regard, in the present invention, since no parts are disposed between the magnifying lens and the workpiece, the distance between the magnifying lens and the workpiece can be shortened, and the magnification by the magnifying lens is increased by using a lens having a short focal length. Can do.
In each displacement detection apparatus described above, the beam splitter may be a non-polarizing beam splitter or a polarizing beam splitter, and may be plate-shaped or cube-shaped.

  In the present invention, comprising a ¼ wavelength plate disposed between the beam splitter and the workpiece, the beam splitter is a polarizing beam splitter that transmits almost all light having a predetermined polarization direction, The illumination optical system preferably makes the laser beam polarized in a direction orthogonal to the polarization direction of the polarization beam splitter incident on the polarization beam splitter.

In this configuration, for example, when the polarization beam splitter passes almost all P-polarized light and the illumination optical system emits S-polarized light, the light emitted from the illumination optical system and incident on the polarization beam splitter is polarized. The beam splitter reflects almost everything toward the workpiece.
When the light reflected from the work surface returns to the polarizing beam splitter, the light passes through the quarter-wave plate twice between the polarizing beam splitter and the work, so that the S-polarized light is rotated 90 degrees. , And enters the polarization beam splitter as P-polarized light. Therefore, almost all of the light returning from the work to the polarizing beam splitter passes through the polarizing beam splitter and is received by the imaging means.

In this way, almost all of the light incident on the polarization beam splitter from the illumination optical system is reflected toward the workpiece, and almost all of the light returning from the workpiece to the polarization beam splitter is transmitted toward the imaging unit. Light loss can be reduced.
For example, when the light is split by 1/2 with the beam splitter, the light amount is reduced to 1/4 when the light is passed through the beam splitter twice. About 4 times the amount of light can be received. Therefore, a clear speckle image is obtained with a sufficient amount of light, and the detection accuracy is improved by this clear speckle image. Further, since the light loss is small, the laser output of the illumination optical system can be reduced, and by using a small laser light source, the displacement detection device can be reduced in size and price.

The polarizing beam splitter may be plate-shaped or cube-shaped.
And when making a beam splitter into a cube type, you may provide a quarter wavelength plate integrally in a cube type beam splitter.

The displacement detection apparatus of the present invention includes an illumination optical system that irradiates laser light toward the workpiece surface, and an imaging unit that captures a speckle image generated by light scattered on the workpiece surface. A displacement detection device that detects a relative displacement amount of a workpiece in a direction substantially orthogonal to a normal line of the workpiece based on a change in the speckle image, wherein the illumination optical system is substantially The laser beam is irradiated vertically, the imaging means receives light scattered in a substantially vertical direction of the workpiece surface, and the displacement detection device is disposed on the normal line of the workpiece. A polarizing beam splitter that transmits almost all light in a predetermined polarization direction; a quarter-wave plate disposed between the workpiece and the polarizing beam splitter; the workpiece and the polarizing beam splitter; A larger lens disposed between the reflecting mirror disposed on the workpiece opposite to between the polarizing beam splitter, disposed between the reflective mirror and the polarization beam splitter 1 / A four-wave plate, and the illumination optical system causes the laser beam polarized in a direction orthogonal to the polarization direction of the polarization beam splitter to enter the polarization beam splitter, and the imaging means transmits the light from the workpiece. The polarizing beam splitter is disposed at a position for receiving light reflected in a direction orthogonal to the normal direction of the workpiece, and the polarization beam splitter reflects light from the illumination optical system toward the workpiece, and from the workpiece. that the light is reflected toward the imaging means recursion light to the polarization beam splitter is reflected by the reflection mirror after the reflected light is transmitted toward the reflective mirror And features.

According to such a configuration , the following operations and effects are exhibited in addition to the operations and effects substantially the same as those of the displacement detection device described above.
For example, when the polarization beam splitter passes only P-polarized light and the illumination optical system emits S-polarized light, almost all light incident on the polarization beam splitter from the illumination optical system is directed toward the work by the polarization beam splitter. Reflected. Then, when the light reflected from the workpiece surface returns to the polarization beam splitter, the S-polarized light is rotated 90 degrees between the polarization beam splitter and the workpiece twice, so that the S-polarized light is rotated by 90 degrees and P-polarized light is passed. Is incident on the polarization beam splitter.
Therefore, almost all the light returning from the work to the polarizing beam splitter passes through the polarizing beam splitter and travels to the reflecting mirror, and the light reflected by the reflecting mirror returns to the polarizing beam split.
Here, since the light passes through the quarter wavelength plate twice between the polarizing beam splitter and the reflecting mirror, the polarization direction of the light is rotated by 90 degrees, and the recursive light from the reflecting mirror is converted to S-polarized light. Return to the polarizing beam splitter. Thus, the light that has returned to the polarization beam splitter as S-polarized light is reflected by the polarization beam splitter toward the image pickup means and received by the image pickup means.

According to such a configuration, almost all of the light incident on the polarization beam splitter from the illumination optical system is reflected toward the workpiece, and almost all of the light returning from the workpiece to the polarization beam splitter passes through the reflection mirror. Since the light is received by the image pickup means, the light loss can be reduced.
Since the loss of light amount can be reduced, a clear speckle image can be obtained with a sufficient amount of light, and the detection accuracy is improved by this clear speckle image.

Further, since the imaging means is disposed at a position for receiving light reflected in a direction perpendicular to the normal direction of the workpiece, the thickness in the normal direction of the workpiece can be reduced.
At this time, in order to maintain the magnification ratio of the speckle image, it is necessary to make the optical path length between the magnifying lens and the imaging means long to some extent, because the light is reciprocated between the polarization beam splitter and the reflection mirror, The optical path length can be earned by this reciprocating optical path. Therefore, it is not necessary to make the distance between the imaging unit and the polarization beam splitter so long, and the planar dimension of the displacement detection device can be reduced.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be illustrated and described with reference to reference numerals attached to respective elements in the drawings.
(First embodiment)
A first embodiment of the displacement detection apparatus of the present invention will be described with reference to FIG.
The displacement detection apparatus 100 includes a casing 110 having a storage space 111 therein, an illumination optical system 120 that irradiates laser light toward the workpiece W, and a speckle image generated by scattered light from the workpiece W. A CCD camera (imaging means) 130 for capturing the image, a magnifying lens 140 for magnifying an image of scattered light from the workpiece W toward the CCD camera 130, an aperture 150 disposed at the focal position of the magnifying lens 140, and a magnification A beam splitter 160 disposed between the lens 140 and the workpiece W, and an image processing unit 170 that performs image processing on an output image from the CCD camera 130 are provided.

The illumination optical system 120 includes a laser light source 121, a collimating lens 122 that converts the light L1 from the laser light source 121 into a parallel light beam, a reflection mirror 123 that reflects the light from the collimating lens 122 toward the beam splitter 160, Is provided.
Here, the beam splitter 160 has a plate shape, reflects the light from the illumination optical system 120, and irradiates the laser beam (L3) substantially perpendicularly to the workpiece surface S.
The beam splitter 160 may be a non-polarizing beam splitter or a polarizing beam splitter.
Further, the magnifying lens 140, the aperture 150, and the CCD camera 130 are arranged in order of the magnifying lens 140, the aperture 150, and the CCD camera 130 on the normal line of the workpiece surface S so as to have an optical axis in a direction substantially perpendicular to the workpiece W. It is installed.

  The surface S of the workpiece W is an optically rough surface (optical rough surface). The workpiece W and the displacement detection device 100 can be relatively moved in a direction orthogonal to the normal line of the workpiece surface S. The displacement detection device 100 can move the workpiece W in a direction orthogonal to the normal line of the workpiece surface S. Detect displacement.

In such a configuration, the light (L 1) emitted from the laser light source 121 is converted into a parallel light beam by the collimator lens 122 and enters (L 2) the beam splitter 160 via the reflection mirror 123. A part of the laser beam (L2) is reflected toward the workpiece surface S by the beam splitter 160, and enters the workpiece surface S perpendicularly (L3). The laser beam (L3) incident on the workpiece surface S is reflected by the workpiece surface S and again enters the beam splitter 160 (L4). A part of the light (L4) incident on the beam splitter 160 passes through the beam splitter 160 and enters the CCD camera 130 via the magnifying lens 140 and the aperture 150 (L5). Then, a speckle image is picked up by the CCD camera 130. Note that the speckled image has a speckled pattern as the aperture 150 reduces the light. An image captured by the CCD camera 130 is output to the image processing unit 170.
Then, the reference speckle image acquired at the standard position of the workpiece W is compared with the current speckle image acquired when the workpiece W is displaced, and the workpiece W is based on the displacement of the matching pattern in the image. Displacement is detected.

According to 1st Embodiment provided with such a structure, there exists the following effect.
(1) Since the light from the illumination optical system 120 is irradiated substantially perpendicularly to the workpiece surface S, the irradiation position of the light does not shift on the workpiece surface S even when the workpiece W fluctuates in the normal direction. Therefore, even if the workpiece W fluctuates in the normal direction, the speckle image picked up by the CCD camera 130 does not change, and the amount of reflected light from the workpiece W does not change. Therefore, the displacement in the direction substantially perpendicular to the normal direction of the workpiece W can be accurately detected regardless of the variation in the normal direction of the workpiece W.

(2) Even if the wavelength of the laser beam fluctuates due to temperature changes, the light is incident on the workpiece W substantially perpendicularly and the light reflected in the vertical direction from the workpiece W is received by the CCD camera 130. The light interference position does not change, and the workpiece displacement can be detected with high accuracy regardless of the change in wavelength.

(Modification 1)
As a first modification, a modification of the first embodiment will be described with reference to FIG.
The basic configuration of the first modification is the same as that of the first embodiment. Here, in the first embodiment, in the illumination optical system 120, the light (L 1) from the laser light source 121 passes through the collimator lens 122 and is then reflected by the reflection mirror 123 and guided to the beam splitter 160. In this regard, the first modification is characterized in that the light (L1) from the laser light source 121 is directly incident on the beam splitter 160 after being converted into a parallel light beam (L2) by the collimator lens 122.

(Modification 2)
As a second modification, a modification of the first embodiment will be described with reference to FIG.
The basic configuration of Modification 2 is the same as that of the first embodiment, but is characterized in that the beam splitter 161 is not a plate but a cube.

(Modification 3)
As a third modification, a modification of the first embodiment will be described with reference to FIG.
The basic configuration of Modification 3 is the same as that of the first embodiment.
Here, in FIG. 4, the beam splitter is a plate-shaped polarization beam splitter 162 that transmits only P-polarized light. A quarter wavelength plate 180 is disposed between the polarization beam splitter 162 and the workpiece W. The laser light source 121 emits S-polarized light (L6).

In such a configuration, the S-polarized laser beam (L6) emitted from the laser light source 121 enters the polarization beam splitter 162 via the collimator lens 122 (L7). Then, the polarization beam splitter 162 reflects (L8) almost all the S-polarized laser light (L7) toward the workpiece surface S. Then, when the light (L9) reflected by the workpiece surface S returns to the polarizing beam splitter 162, the light (L8, L9) passes through the quarter-wave plate 180 twice between the polarizing beam splitter 162 and the workpiece W. Since it passes, it enters the polarization beam splitter 162 as P-polarized light (L9). Therefore, almost all the light (L9) recursed from the workpiece W to the polarization beam splitter 162 is transmitted through the polarization beam splitter 162 and received by the CCD camera 130 (L10).
As described above, almost all the light (L7) incident on the polarization beam splitter 162 from the laser light source 121 is reflected toward the work W, and the light (L9) returning from the work W to the polarization beam splitter 162 is almost total. Therefore, the loss of light quantity can be reduced.

(Modification 4)
As a modification 4, a modification of the first embodiment will be described with reference to FIG.
Here, the basic configuration of the modified example 4 is the same as that of the modified example 3 described above, but the polarizing beam splitter 163 is a cube type, and the quarter wave plate 180 is provided integrally with the polarizing beam splitter 163. It has a feature in that.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG.
The basic configuration of the second embodiment is the same as that of the first embodiment, but is characterized in that the beam splitter 160 is disposed between the magnifying lens 140 and the aperture 150.
Further, in FIG. 6, a collimator lens 122 and a relay lens 124 are disposed between the laser light source 121 and the beam splitter 160.
The collimating lens 122 converts the light (L11) from the laser light source 121 into a parallel light beam.
The relay lens 124 is disposed so that its focal position matches the focal position of the magnifying lens 140.

In this configuration, the light (L 11) from the laser light source 121 is converted into a parallel light beam by the collimator lens 122, further focused at the focal position by the relay lens 124, and then reflected toward the magnifying lens 140 by the beam splitter 160 (L 12). ) When the focal position of the relay lens 124 coincides with the focal position of the magnifying lens 140, the magnifying lens 140 converts the light (L12) into a parallel luminous flux and irradiates the surface S of the workpiece W.
Then, the reflected light (L13) from the workpiece surface S is imaged (L14) by the CCD camera 130 via the magnifying lens 140, the beam splitter 160, and the aperture 150.

According to such 2nd Embodiment, in addition to said effect (1) (2), there exists the following effect.
(3) When the aperture 150 is disposed at the focal position of the magnifying lens 140, the beam splitter 160 is disposed between the magnifying lens 140 and the aperture 150, so that it exists as a space in the displacement detection device 100 from the beginning. Since the beam splitter 160 is arranged at the place where the displacement is detected, the dead space can be eliminated and the displacement detecting device 100 can be thinned.
(4) Since no member is disposed between the magnifying lens 140 and the workpiece W, the distance between the magnifying lens 140 and the workpiece W can be shortened, and a magnification with the magnifying lens 140 is increased by using a lens having a short focal length. can do.

(Modification 5)
As Modification 5, a modification of the second embodiment will be described with reference to FIG.
The basic configuration of Modification 5 is the same as that of the second embodiment, but is characterized in that the beam splitter 161 is a cube type in FIG.

(Modification 6)
As a modification 6, a modification of the second embodiment will be described with reference to FIG.
The basic configuration of Modification 6 is the same as that of the second embodiment, but in FIG. 8, only the relay lens 124 is disposed between the laser light source 121 and the beam splitter 160 and emitted from the laser light source 121. The light L 11 is characterized by being incident on the beam splitter 160 after being focused at the focal position by the relay lens 124.

(Modification 7)
As a modified example 7, a modified example of the second embodiment will be described with reference to FIG.
The basic configuration of Modification 7 is the same as that of the second embodiment.
Here, in FIG. 9, a relay lens 124 is disposed between the laser light source 121 and the beam splitter 161, and the beam splitter 161 is a cube type.

(Modification 8)
As a modification 8, a modification of the second embodiment will be described with reference to FIG.
The basic configuration of the modified example 8 is the same as that of the second embodiment, but the beam splitter is a polarizing beam splitter 162, and a quarter wavelength plate 180 is disposed between the polarizing beam splitter 162 and the magnifying lens 140. It is characterized in that it is installed.
Here, the polarization beam splitter 162 passes only P-polarized light. The laser light source 121 emits S-polarized light L15.

In this configuration, almost all the light (L15) incident on the polarization beam splitter 162 from the laser light source 121 is reflected (L16) toward the workpiece W. Then, when the light (L17) reflected by the workpiece surface S returns to the polarization beam splitter 162, the light (L16, L17) passes through the quarter wavelength plate 180 twice between the polarization beam splitter 162 and the workpiece W. Since it passes, it enters the polarization beam splitter 162 as P-polarized light. Therefore, almost all the light (L17) recursed from the workpiece W to the polarization beam splitter 162 passes through the polarization beam splitter 162 and is imaged (L18) by the CCD camera 130.
As described above, almost all the light (L15) incident on the polarization beam splitter 162 from the laser light source 121 is reflected toward the work W, and the light (L17) returning from the work W to the polarization beam splitter 162 is almost total. Since the light is transmitted (L18) toward the CCD camera 130, the light amount loss can be reduced.

(Modification 9)
As a modification 9, a modification of the second embodiment will be described with reference to FIG.
The basic configuration of the modified example 9 is the same as that of the modified example 8 except that the polarizing beam splitter 163 is a cube type and the quarter wavelength plate 180 is integrally provided on the polarizing beam splitter 163. Has characteristics.

(Modification 10)
As a modification 10, a modification of the second embodiment will be described with reference to FIG.
Here, the basic configuration of the modification 10 is the same as that of the modification 8, but is characterized in that only the relay lens 124 is disposed between the laser light source 121 and the polarization beam splitter 162.

(Modification 11)
As a modification 11, a modification of the second embodiment will be described with reference to FIG.
Here, the basic configuration of the modification 11 is the same as that of the modification 8, but the polarization beam splitter 163 is a cube type, and the quarter wavelength plate 180 is integrally provided on the polarization beam splitter 163. It has a feature in that.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG.
The basic configuration of the third embodiment is the same as that of the first embodiment, but is characterized in that the beam splitter 160 is disposed between the aperture 150 and the CCD camera 130.
Further, in FIG. 14, a collimator lens 122 and a relay lens 124 are disposed between the laser light source 121 and the beam splitter 160. The collimating lens 122 converts the light from the laser light source 121 into a parallel light beam, and the relay lens 124 is disposed with its focal position coincident with the focal position of the magnifying lens 140. Note that the focal positions of the relay lens 124 and the magnifying lens 140 coincide with the position of the aperture 150.

  In this configuration, light (L 19) from the laser light source 121 is reflected (L 20) toward the magnifying lens 140 by the beam splitter 160 via the collimator lens 122 and the relay lens 124. At this time, the light (L20) focused at the position of the aperture 150 by the relay lens 124 passes through the aperture 150 and is incident on the magnifying lens 140. The magnifying lens 140 converts the light into a parallel light beam and irradiates the surface S of the workpiece W. (L21). Then, the reflected light (L22) from the workpiece surface S is received by the CCD camera 130 (L23) via the magnifying lens 140, the aperture 150, and the beam splitter 160.

According to such 3rd Embodiment, in addition to said effect (1) (2) (4), there exists the following effect.
(5) Since the beam splitter 160 is disposed between the aperture 150 and the CCD camera 130, the beam splitter 160 is disposed at a place that exists as a space in the displacement detection apparatus 100 from the beginning. The dead space can be eliminated and the displacement detecting device 100 can be thinned.

(Modification 12)
As a modification 12, a modification of the third embodiment will be described with reference to FIG.
The basic configuration of the modification 12 is the same as that of the third embodiment, but is characterized in that the beam splitter 161 is a cube type.

(Modification 13)
As a modification 13, a modification of the third embodiment will be described with reference to FIG.
The basic feature of the modified example 13 is the same as that of the third embodiment. However, in FIG. 16, only the relay lens 124 is provided between the laser light source 121 and the beam splitter 160.

(Modification 14)
As a modification 14, a modification of the third embodiment will be described with reference to FIG.
Here, the basic configuration of the modification 14 is the same as that of the modification 13, but is characterized in that the beam splitter 161 is a cube type.

(Modification 15)
As a modification 15, a modification of the third embodiment will be described with reference to FIG.
The basic configuration of the modification 15 is the same as that of the third embodiment, but the beam splitter is a polarization beam splitter 162, and a ¼ wavelength plate 180 is disposed between the polarization beam splitter 162 and the aperture 150. It is characterized in that Here, the polarization beam splitter 162 passes only P-polarized light. The laser light source 121 emits S-polarized laser light.

In this configuration, almost all light (L24) incident on the polarization beam splitter from the laser light source 121 is reflected (L25) toward the workpiece W.
Then, when the light (L26) reflected by the workpiece surface S returns to the polarization beam splitter 162, the light passes through the quarter-wave plate 180 twice between the polarization beam splitter 162 and the workpiece W. The light enters the polarization beam splitter 162 as polarized light. Therefore, almost all the light (L26) recursed from the work W to the polarization beam splitter 162 passes through the polarization beam splitter 162 and is imaged by the CCD camera 130.

  As described above, almost all of the light incident on the polarization beam splitter 162 from the laser light source 121 is reflected toward the workpiece W, and all of the light returning from the workpiece W to the polarization beam splitter 162 is directed toward the CCD camera 130. The light loss can be reduced.

(Modification 16)
As a modification 16, a modification of the third embodiment will be described with reference to FIG.
The basic configuration of the modified example 16 is the same as that of the modified example 15 except that the polarizing beam splitter 163 is a cube type and the quarter wavelength plate 180 is provided integrally with the beam splitter 163. Has characteristics.

(Modification 17)
As a modified example 17, a modified example of the third embodiment will be described with reference to FIG.
The basic configuration of the modified example 17 is the same as that of the modified example 15 except that only the relay lens 124 is disposed between the laser light source 121 and the polarization beam splitter 162.

(Modification 18)
As a modification 18, a modification of the third embodiment will be described with reference to FIG.
The basic configuration of the modified example 18 is the same as that of the modified example 16, but is characterized in that only the relay lens 124 is disposed between the laser light source 121 and the polarization beam splitter 163.

(Fourth embodiment)
A fourth embodiment of the present invention will be described with reference to FIG.
The basic configuration of the fourth embodiment is the same as that of the first embodiment.
Here, in the first embodiment, as shown in FIG. 1, the magnifying lens 140, the beam splitter 160, and the CCD camera 130 are sequentially arranged in the normal direction of the workpiece W.
In this regard, in the fourth embodiment, the CCD camera 130 is disposed at a position where light reflected in a direction perpendicular to the normal direction of the workpiece W can be received.

That is, the reflected light from the work W passes through the magnifying lens 140, is reflected by the reflecting mirror 190, is further reflected by the polarizing beam splitter 162 at a right angle, and is bent by the optical path, and then received by the CCD camera 130. The In FIG. 22, a magnifying lens 140, an aperture 150, and a polarization beam splitter 162 are disposed in the normal direction of the workpiece W, and a reflection mirror 190 is further disposed. A quarter wavelength plate 180 is disposed between the polarization beam splitter 162 and the aperture 150, and a quarter wavelength plate 191 is disposed between the polarization beam splitter 162 and the reflection mirror 190.
Here, the polarization beam splitter 162 passes only P-polarized light. The laser light source 121 emits S-polarized laser light.

  In this configuration, the light (L28) emitted from the laser light source 121 enters the polarization beam splitter 162 via the relay lens 124. When S-polarized light is emitted from the laser light source 121, it is reflected (L 29) toward the workpiece W by the polarization beam splitter 162. The light (L29) reflected by the polarization beam splitter 162 passes through the quarter-wave plate 180, the aperture 150, and the magnifying lens 140, and is irradiated onto the workpiece W perpendicularly (L30). The light (L30) irradiated on the workpiece W is reflected by the workpiece W, passes through the magnifying lens 140, the aperture 150, and the quarter wavelength plate 180 and returns to the beam splitter (L31).

Here, since the light (L29, L30, L31) passes through the quarter wavelength plate 180 twice between the polarization beam splitter 162 and the workpiece W, the light (L28) emitted as S-polarized light from the laser light source 121 is Return to the polarization beam splitter as P-polarized light (L31).
Accordingly, almost all of the light (L31) that has returned to the polarization beam splitter 162 passes through the polarization beam splitter 162, travels straight toward the reflection mirror 190 (L32), and is further reflected (L33) by the reflection mirror 190. Return to the polarization beam splitter 162.

  Here, since the light (L32, L33) passes through the quarter-wave plate 191 twice between the polarizing beam splitter 162 and the reflecting mirror 190, the light (L32) that has passed through the polarizing beam splitter 162 as P-polarized light. ) Returns to the polarization beam splitter 162 as S-polarized light (L33). Then, the light (L33) recursed as S-polarized light from the reflection mirror 190 to the polarization beam splitter 162 is reflected toward the CCD camera 130 by the polarization beam splitter 162 and received by the CCD camera 130 (L34).

According to such 4th Embodiment, in addition to said effect (1) (2) (4), there can exist the following effect.
(6) The light (L28) incident on the polarization beam splitter 162 from the laser light source 121 is reflected almost toward the workpiece W (L29), and the light (L31) returning from the workpiece W to the polarization beam splitter 162 is returned. Since almost all light is received by the CCD camera 130 via the reflection mirror 190 (L34), the loss of light quantity can be reduced.
Since the loss of light amount can be reduced, a clear speckle image can be obtained with a sufficient amount of light, and the detection accuracy of the workpiece displacement can be improved by this clear speckle image.

(7) Since the CCD camera 130 is disposed at a position for receiving light reflected in a direction perpendicular to the normal direction of the workpiece W, the thickness of the displacement detection device 100 can be reduced.

(8) In order to maintain the magnification ratio of the speckle image, it is necessary to increase the optical path length between the magnifying lens 140 and the CCD camera 130 to some extent, and light is transmitted between the polarization beam splitter 162 and the reflection mirror 190. Since it is made to reciprocate, an optical path length can be earned by this reciprocating optical path. Therefore, it is not necessary to make the distance between the CCD camera 130 and the polarization beam splitter 162 so long, and the planar dimension of the displacement detection device 100 can be reduced.

(Modification 19)
As a modification 19, a modification of the fourth embodiment will be described with reference to FIG.
The basic configuration of the modification 19 is the same as that of the fourth embodiment, but the polarization beam splitter 163 is a cube type, and the two quarter-wave plates 180 and 191 and the reflection mirror 190 are the polarization beam splitter 162. It is characterized in that it is provided integrally with.

(Modification 20)
As a modification 20, a modification of the fourth embodiment will be described with reference to FIG.
Here, the basic configuration of Modification 20 is the same as that of Modification 19, except that a polarizing plate 125 is disposed between the laser light source 121 and the polarization beam splitter 163.
Then, the light (L28) from the laser light source 121 is filtered by the polarizing plate 125, and only the S-polarized light enters the polarizing beam splitter 163 (L281).

According to this configuration, the light (L281) that passes through the polarizing plate 125 and is incident on the polarization beam splitter 163 is substantially all accurate S-polarized light, and therefore is substantially reflected by the polarization beam splitter 163 toward the workpiece W. Is done.
Here, for example, in the fourth embodiment and the modified example 19, it is assumed that S-polarized light is emitted from the laser light source 121. However, not all S-polarized light is accurately emitted, and polarized light other than S-polarized light is used. Directional light will also be mixed somewhat. At this time, part of the light (L 28) from the laser light source 121 may pass through the polarization beam splitter 163 and enter the CCD camera 130.
Then, noise is mixed with the speckle image to be imaged by the CCD camera 130, and a clear speckle image cannot be obtained.
In this regard, in Modification 20, since the light (L28) from the laser light source 121 is filtered by the polarizing plate 125, the light (L281) incident on the polarization beam splitter 163 from the laser light source 121 is transmitted through the polarization beam splitter 163. There is nothing. As a result, the CCD camera 130 can capture a clear speckle image without noise.

(Fifth embodiment)
A fifth embodiment of the present invention will be described with reference to FIG.
The basic configuration of the fifth embodiment is the same as that of the first embodiment, but in the fifth embodiment, the aperture is an eccentric aperture 200 and the opening (light transmission portion) 210 is shifted from the center. It is characterized by being provided in.
That is, the eccentric aperture 200 has an opening 210 at a position shifted from the center point, as shown in FIG.

  In this configuration, the light reflected from the workpiece W passes through the beam splitter 160 and the magnifying lens 140 and enters the eccentric aperture 200, and the zero-order light (L35) reflected perpendicularly from the workpiece W is the eccentric aperture 200. Is shielded by. On the other hand, the light (L 36) scattered in the direction deviated from the normal line of the workpiece surface S passes through the opening 210 of the eccentric aperture 200 and is received by the CCD camera 130.

According to such a configuration, in addition to the above effects (1) and (2), the following effects can be obtained.
(9) Of the light reflected from the workpiece surface S (L35, L36), the speckle image is generated by the light scattered by the workpiece surface S (L36). Since the 0th-order light (L35) reflected perpendicularly at 1 is shielded and only the scattered light (L36) contributing to the generation of the speckle image is transmitted toward the CCD camera 130, the CCD camera 130 has clear speckle. An image can be taken.

(Modification 21)
As a modification 21, a modification of the fifth embodiment will be described with reference to FIG.
The basic configuration of the modified example 21 is the same as that of the fifth embodiment, but the eccentric aperture 200 has an annular light transmission part 210 at a position shifted from the center as shown in FIG. Characterized by points.
Such an annular light transmitting portion 210 can be realized, for example, by forming a mask that leaves an annular portion on one surface of a glass plate.

  Here, the eccentric aperture 200 of the fifth embodiment is not limited to the above example. For example, as shown in FIGS. 29 (A), (B), and (C), a plurality of eccentric apertures 200 are arranged at positions shifted from the center. You may have the opening part 210. FIG. That is, as shown in FIG. 29 (A), two openings 210 may be provided at positions shifted from the center, and three openings at positions shifted from the center as shown in FIG. 29 (B). A portion 210 may be included, and four openings 210 may be provided at positions shifted from the center as shown in FIG.

  In the configuration described in the first embodiment, Modification 1 to Modification 4, Second Embodiment, Modification 5 to Modification 11, the aperture 150 may be replaced with the eccentric aperture 200.

The present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.
For example, in the embodiment and the modification described above, the workpiece is moved with respect to the displacement detection device. However, since the displacement detection device detects a relative displacement amount with respect to the workpiece, the displacement detection device is displaced with respect to the workpiece. Of course it is good.
Although the case where the magnifying lens is a single lens has been described as an example, it may be a lens system in which a plurality of lenses are combined.

  The present invention can be used in a displacement detection device that detects the displacement of a workpiece.

The figure which shows the structure of 1st Embodiment which concerns on the displacement detection apparatus of this invention. The figure which shows the structure of the modification 1. FIG. The figure which shows the structure of the modification 2. The figure which shows the structure of the modification 3. The figure which shows the structure of the modification 4. The figure which shows the structure of 2nd Embodiment which concerns on the displacement detection apparatus of this invention. The figure which shows the structure of the modification 5. The figure which shows the structure of the modification 6. The figure which shows the structure of the modification 7. The figure which shows the structure of the modification 8. The figure which shows the structure of the modification 9. The figure which shows the structure of the modification 10. The figure which shows the structure of the modification 11. The figure which shows the structure of 3rd Embodiment which concerns on the displacement detection apparatus of this invention. The figure which shows the structure of the modification 12. The figure which shows the structure of the modification 13. The figure which shows the structure of the modification 14. The figure which shows the structure of the modification 15. The figure which shows the structure of the modification 16. The figure which shows the structure of the modification 17. The figure which shows the structure of the modification 18. FIG. The figure which shows the structure of 4th Embodiment which concerns on the displacement detection apparatus of this invention. The figure which shows the structure of the modification 19. The figure which shows the structure of the modification 20. The figure which shows the structure of 5th Embodiment which concerns on the displacement detection apparatus of this invention. The figure which shows the structure of an eccentric aperture in 5th Embodiment. The figure which shows the structure of the modification 21. FIG. In the modification 21, the figure which shows the structure of an eccentric aperture. The figure which shows the example of an eccentric aperture. The figure which shows the structure of the conventional displacement detection apparatus. The figure which shows an example of a speckle image. The figure which shows the laser irradiation position when a workpiece | work moves to the normal line direction. The figure which shows a mode that the optical path of interference light changes when the wavelength of a laser beam changes.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Displacement detection apparatus, 11 ... Housing | casing part, 12 ... Storage space, 13 ... Illumination optical system, 14 ... Laser light source, 15 ... Collimating lens, 16 ... CCD camera, 17 ... Magnifying lens, 18 ... Aperture, 19 ... Image Processing unit, 100: Displacement detection device, 110: Housing unit, 111: Storage space, 120 ... Illumination optical system, 121 ... Laser light source, 122 ... Collimator lens, 123 ... Reflection mirror, 124 ... Relay lens, 125 ... Polarizing plate , 130 ... CCD camera (imaging means), 140 ... magnifying lens, 150 ... aperture, 160 ... beam splitter, 161 ... beam splitter, 162 ... polarization beam splitter, 163 ... polarization beam splitter, 170 ... image processing unit, 180 ... 1 / 4 wavelength plate, 190 ... reflecting mirror, 191 ... quarter wavelength plate, 200 ... eccentric aperture 210 ... opening (light transmitting portion).

Claims (5)

An illumination optical system that emits laser light toward the workpiece surface;
Imaging means for capturing a speckle image generated by light scattered on the workpiece surface,
A displacement detection device that detects a relative displacement amount of a workpiece in a direction substantially orthogonal to a normal line of the workpiece based on a change in the captured speckle image,
The illumination optical system irradiates the laser light substantially perpendicularly to the workpiece surface,
The imaging means receives light scattered toward a substantially vertical direction of the workpiece surface ,
The displacement detector is
A beam splitter disposed on the normal of the workpiece surface;
A magnifying lens that is arranged between the workpiece and the imaging means and expands an image of light scattered on the workpiece surface toward the imaging means;
An aperture disposed at a focal position of the magnifying lens between the magnifying lens and the imaging means;
The beam splitter is disposed between the magnifying lens and the workpiece, reflects light incident from the illumination optical system in a direction substantially perpendicular to the surface of the workpiece, and reflects the laser beam to the workpiece. While irradiating the workpiece, the light scattered from the workpiece surface is transmitted toward the imaging means,
The aperture detection apparatus according to claim 1, wherein the aperture shields light vertically reflected on the work surface and transmits light deviated from a normal line of the work surface toward the imaging unit . An illumination optical system that emits laser light toward the workpiece surface;
Imaging means for capturing a speckle image generated by light scattered on the workpiece surface,
A displacement detection device that detects a relative displacement amount of a workpiece in a direction substantially orthogonal to a normal line of the workpiece based on a change in the captured speckle image,
The illumination optical system irradiates the laser light substantially perpendicularly to the workpiece surface,
The imaging means receives light scattered toward a substantially vertical direction of the workpiece surface,
The displacement detector is
A beam splitter disposed on the normal of the workpiece surface;
And enlarging lens for enlarging toward an image on said imaging means by light scattered by the workpiece surface disposed between the workpiece and the imaging means,
An aperture disposed at a focal position of the magnifying lens between the magnifying lens and the imaging means,
The beam splitter is disposed between the aperture and the magnifying lens, and reflects the light incident from the illumination optical system in a direction substantially perpendicular to the work surface to reflect the laser light. While irradiating the workpiece, the light scattered from the workpiece surface is transmitted toward the imaging means,
The aperture detection apparatus according to claim 1, wherein the aperture shields light vertically reflected on the work surface and transmits light deviated from a normal line of the work surface toward the imaging unit . An illumination optical system that emits laser light toward the workpiece surface;
Imaging means for capturing a speckle image generated by light scattered on the workpiece surface,
A displacement detection device that detects a relative displacement amount of a workpiece in a direction substantially orthogonal to a normal line of the workpiece based on a change in the captured speckle image,
The illumination optical system irradiates the laser light substantially perpendicularly to the workpiece surface,
The imaging means receives light scattered toward a substantially vertical direction of the workpiece surface,
The displacement detector is
A beam splitter disposed on the normal of the workpiece surface;
And enlarging lens for enlarging toward an image on said imaging means by light scattered by the workpiece surface disposed between the workpiece and the imaging means,
An aperture disposed at a focal position of the magnifying lens between the magnifying lens and the imaging means,
The beam splitter is disposed between the aperture and the imaging means, and reflects the light incident from the illumination optical system in a direction substantially perpendicular to the work surface to reflect the laser light. While irradiating the workpiece, the light scattered from the workpiece surface is transmitted toward the imaging means,
The aperture detection apparatus according to claim 1, wherein the aperture shields light vertically reflected on the work surface and transmits light deviated from a normal line of the work surface toward the imaging unit . In the displacement detection apparatus in any one of Claims 1-3 ,
Comprising a quarter wave plate disposed between the beam splitter and the workpiece;
The beam splitter is a polarizing beam splitter that transmits almost all light having a predetermined polarization direction,
The displacement optical apparatus is characterized in that the illumination optical system makes laser light polarized in a direction orthogonal to a polarization direction of the polarization beam splitter incident on the polarization beam splitter. An illumination optical system that emits laser light toward the workpiece surface;
Imaging means for capturing a speckle image generated by light scattered on the workpiece surface,
A displacement detection device that detects a relative displacement amount of a workpiece in a direction substantially orthogonal to a normal line of the workpiece based on a change in the captured speckle image,
The illumination optical system irradiates the laser light substantially perpendicularly to the workpiece surface,
The imaging means receives light scattered toward a substantially vertical direction of the workpiece surface,
The displacement detector is
A polarization beam splitter that is disposed on the normal line of the workpiece and transmits almost all light in a predetermined polarization direction; and
A quarter-wave plate disposed between the workpiece and the polarizing beam splitter;
A larger lens disposed between said workpiece and said polarization beam splitter,
A reflecting mirror disposed on the opposite side of the workpiece with the polarizing beam splitter in between;
A quarter wave plate disposed between the polarizing beam splitter and the reflecting mirror,
The illumination optical system makes laser light polarized in a direction orthogonal to the polarization direction of the polarization beam splitter incident on the polarization beam splitter,
The imaging means is disposed at a position for receiving light reflected from the work in a direction perpendicular to the normal direction of the work,
The polarization beam splitter reflects light from the illumination optical system toward the workpiece, and transmits reflected light from the workpiece toward the reflection mirror, and then reflects the light on the reflection mirror. Then, the light that has been returned to the polarization beam splitter is reflected toward the imaging means.

Images