JPS60500270A - Inspection equipment and method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Inspection equipment and method The present invention relates to apparatus and methods for use in testing.

The object to be inspected consists of lens surfaces and mirror surfaces. surfaces such as bars, tinplates, or other types of surfaces such as painted surfaces. Okay...

The present invention includes an apparatus and method for comparing a standard wound and a test wound. Kaka This technique is used by providing a reference on the surface in advance.

A reference scratch is formed by the following method.

Ruling (Rtbl digging) chemical etching ion-beam etching thin film corrosion fiber Topplication) These techniques are limited, for example, by the diopter range to be cut, cost, and aging sensitivity. and changes in relative diopter under different test conditions, each with its own advantages and disadvantages. have.

According to the present invention, there is provided a mechanism for generating two optical signals, one of which is detected. one is affected by the defect to be inspected, and the other is affected by the reference defect. Mechanism for placing defects to be inspected and standard defects, defects to be inspected and These two optical signals are compared after being influenced by the reference defect and the reference defect, respectively. and one of the two optical signals that are not affected by the above two defects. A comparator is used so that the sum of the light intensity depending on the area is substantially constant. ) for changing the strength of one of the optical signals received by the optical signal. An apparatus is provided for comparing a predetermined defect and a reference defect characterized by: Ru.

According to the present invention, in the process of obtaining two optical signals, one of the optical signals is pass through the defect to be inspected so that it is affected by the defect, and the other second a step of causing the optical signal to pass through a reference defect so that it is affected by the defect; A process of combining the two optical signals, a process of inspecting the combined optical signal, and a process to be inspected. Total intensity of part of two optical signals at °C, unaffected by defects and reference defects. is substantially constant, and the image of the defect to be inspected and the image of the reference defect are the same. two lights until they reach the intensity of and a step of causing the signal strength to vary. A method is provided for comparing defects with .

The invention further provides a method for comparing a predetermined number or set of defects. In the process of obtaining the predetermined number of optical signals, each optical signal is affected by these defects. The process of passing through each defect, combining the optical signals and inspecting them 3 and the total combined optical signal remains substantially constant and free from defects. The optical signal is A comparison method is provided comprising: changing the relative intensities of the .

The invention further provides a polarized light source, a mechanism for changing the polarization angle of the polarized light, a polarized light source, a mechanism for changing the polarization angle of the polarized light, Polarizing beam splitter for splitting light into two optical signals - 1 surface to be inspected and Place the defect on the surface to be inspected, and one of the two optical signals detects the defect on the surface to be inspected. and the other optical signal is affected by the defect that should serve as a reference. mechanism, and after these optical signals are affected by these defects, these two optical A surface defect characterized by comprising a mechanism for comparing signals and a reference standard. An apparatus is provided for comparing defects with defects.

According to the present invention, in the step of obtaining a polarized light source, the polarized light is transmitted through a local beam splitter. The process of splitting the optical signal into two, one of the optical signals being inspected for defects. The influence of the defect that causes the optical signal to pass through the defect in such a way as to be influenced by the defect, and to use the other optical signal as a reference. A process of passing through the defect so as to receive an optical signal, and a process of combining and inspecting the two optical signals. The defect to be inspected and the defect to be the standard have the same strength or a predetermined ratio. Polarized light is used to compare the defect to be inspected and the reference defect in a given case. A process of changing the relative intensity of two optical signals so that the angle is changed. Provided is a method for comparing a surface defect characterized by comprising a surface defect with a reference defect. .

As used herein, 'optical' and similar phrases including optical wavelength divergence. to use. However, the technique described in detail can be applied to infrared and The present invention also applies to radiation in the ultraviolet region, and the present invention applies to radiation in the infrared to ultraviolet region. It should be understood that this also extends.

We also use the word defect. Optical elements such as scratches on the lens When inspecting the surface of In this case, the chain includes any images that form an abnormal appearance. also the broadest meaning Also includes test patterns, absorption lines, cells, stars, etc.

Preferred embodiments of the invention will be described in detail below with reference to Examples and the accompanying drawings.

FIG. 1 is a diagram schematically showing a side view of the surface inspection apparatus of the present invention.

FIG. 2 is a graph showing the various signals produced by the use of the apparatus of FIG. Ru.

FIG. 6 is a diagram schematically showing a side view of another embodiment of the surface inspection device.

Figures 4-A to 4-D show how the diopter of the four British standard scratches is changed. This is a diagram.

Figures 5-A to 5-c are representative of television images obtained by the apparatus of Figure 6. It is a figure which shows an example.

FIG. 6 is a diagram schematically showing a side view of still another embodiment of the surface inspection device of the present invention. .

7 and 8 are diagrams showing a portion of the apparatus of FIG. 6 in detail.

In FIG. 1, a light source 101 forms an image point on a pinhole 104 using a lens 102. A polarizer 117 and a polarizer 117 are provided between the lens 102 and the pinhole 104. and an iris diaphragm 106. The aperture 106 is illuminated for inspection and measurement. limit the area of surface 108 that will be exposed.

That is, even if the surface 108 is a curved portion with a small diameter, it is small enough to be considered flat. Only the area is irradiated.

The pinhole 104 is located at the focal point of the lens 106. The light transmitted from 04 is divided into 126 and 1 by polarizing beam splitter 105. 21 and beam 126 passes through lens 106 to surface 10. Reach 8.

The ratio of the intensities (1n intensity) of the two beams 121 and 126 is the polarizer 1 Adjusted by 17 rotations.

The transmitted beam 126 is made into a parallel beam by the lens 106 and passes through the wavelength plate 107. and the reflected beam passes through the leakage wave plate 107 again. . At this time, when the reflected beam returns to the polarizing beam splitter 105, its polarization plane is 1 rotated 80° and reflected by the splitter 105 to form beam 122 and is focused (124) within the plane of the lens 112. This lens 112 is It is used to form an image of surface 108 on the image plane of television camera 116.

A focusing beam sinter 120 converts a portion of the incident beam 122 into a concave reflecting surface 11. 6 and returned to the flat reflective surface 115, and then from the diagonal surface 114. An image point 124 is imaged onto a television camera 116 via a polarizer 117.

The television camera thus effectively receives two sets of images, with the upright image of some surface 108 The autopsy showed surface scratches, and the position of the other central spot was determined by the slope of the surface 108. Therefore, it is determined.

The first of these images is an autopsy image of a portion of the surface 108, which includes the lens. 106 and 112, and the second spot image is formed by lenses 106 and 112. and the focusing surface 116 of the focusing beam splitter 120.

In addition to the location of the central spot indicating the slope of the surface 108, the extent of the central spot is It is affected by the scattering caused by surface 8.

A light source 101 may be reflected at a polarizing beam splitter to form a beam 121. The beam is positioned on a standard or comparison surface 11 with comparison marks and/or measurement graduations. Used to clarify 1. Beam 121 is transmitted through lens 109 and a four-wave plate 110 and reaches the surface 111, and the reflected beam from the surface 111 is again divided into four waves. The light passes through the long plate 110 and the lens 109 and enters the beam splitter 105. mosquito (The image of the surface 111 is captured by the television camera 116 by lenses 109 and 112.) is focused on the image plane of

Therefore, in addition to the two images formed as described above, there is a third image associated with the comparative wound. is formed. Furthermore, the autoplanar beam from surface 111 produces a fourth image. is focused onto camera 116 by concave reflective surface 116.

This spot, along with the image of surface 111, is removed by rotation of polarizer 2040. obtain.

Specific flaws on surface 108 are measured as follows. First surface 108 and surface 1 The reflected rays from 11 must be made equal (ignoring scratches). This equalization The polarization angle of the incident beam 126 is changed by rotating the polarizer 204 back and forth by approximately 10'. Varying the ratio of reflected beam and transmitted beam at polarizing beam splitter 105 This is done by changing the . The reflected beam at the beam splitter 105 like this By changing the relative proportions of the beam and the transmitted beam, the television camera 116 generally Therefore, the received light beam changes in synchronization with the rotation of polarizer 204.

However, if the reflected lights at surfaces 111 and 108 are exactly the same, then one If the light on one side increases a little, the light on the other side will decrease a little accordingly, so camera 1 The total amount of light that 16 receives will remain unchanged. This kind of balance point To set it, it is necessary to rotate the polarizer 204 back and forth approximately 100 degrees. Immediately That is, at a predetermined rotational position of polarizer 117, the trapping rotation of polarizer 204 is It does not affect the light output of the camera 116 in any way (until the second polarizer 20゛4 At this point, the reflected light at surfaces 108 and 111 are even.

In the next operation to accurately measure a given flaw on surface 108, a comparison flaw is It is preferable to change the intensity of the flaw image by considering the intensity of the image. This is beam 1 This is easily accomplished by varying the relative strengths of 21 and 126. this relative Intensity is easily affected by rotation of polarizer 117. That is, the polarizer 117 The rotation changes the polarization angle of the incident beam 126 and further polarizes the beam splitter 1. Change the ratio of 05's reflected beam and transmitted beam. Naturally 1-1, these Even if the relative intensities of the two beams change, the total amount remains constant. It will be understood that When the polarizer 117 is rotated, the intensity of the comparative scratch image increases. Larger than 1 and the intensity of the test flaw image decreases, but the intensity of the comparison flaw image decreases. The opposite is true if In this case, the brightness of the background does not change. of these two statues Is it easy to get even strength? , C operations. Polarization angle must be tested Used to make rigorous measurements of scratches (not subjective).

Next, a description will be given with reference to FIG. FIG. 2 shows the polarizer 117 in three directions (0°, 5° 5°, 90°); In the case of scratches on surface 108 to be tested, column ψ) is for comparison scratches and column (C) indicates the case where intensity signals are combined. This example shows the degree of surface scratches to be tested. That's about twice as many scratches as in the comparison. The intensity in one beam is Halu, z's law If the amount of co〆X changes according to f, then the other beam becomes ? Change by 1n2x do. In this case, the second beam is polarized by 90°, but the sum of the two beams is constant. be. However, the diopter of the comparison flaw and the flaw to be tested changes continuously and the beam intensity The value of X when the degree is adjusted is the optical scale of the scratch to be tested compared to a standard scratch. becomes.

According to Fig. 2, the peak intensity A of the test beam (,z-=Q°) to be tested is Let the intensity at the point of minimum intensity of the flaw image be ((1-4), and the peak of the comparison beam Let the intensity be B(3:=90°) (in this case, let the intensity of the image of the comparison part be B(1-b)). For example, the intensity of the combined beam at the point of minimum intensity is I,=,((1-α) cos2 x+Bs1n”x −−−−−−−−−−47) 1, = A cos2x + B (1-h) 5in2x -----.- (represented by Iil.

Now, if X is adjusted so that I, == I, then equations (1) and (11) the law of nature tan’s = Aα7Bh・・・・・・・・・−・・・・・・・・・・・・・・・・・・・・・ ・・・・・・・・・G11l.

Also, the wavelength plate 107 or 110 is rotated so that it becomes A, -B, preferably If the other polarizer 117A is further rotated within the coupling channel, the flaw value α can be compared. part 0 Calculated immediately from the price.

In this case, if the flaw to be measured is exactly twice that of the flaw for comparison, i.e. α/h−2. For example, when the X values of the flaw to be measured and the comparison part are the same, that is, when It will be 55 degrees or 100 degrees.

If the same scratch is measured repeatedly, it will be measured with an accuracy of ±1°, but this is The diopter (vi, -1 bilty) corresponds to a change within the range of 7 factors. within a single When using a partial 'A comparison flaw, the preferred operating range for the flaw diopter is 64:1 or is 3A to 8 times that of the internal comparison section. The instrument measures the diopter of the wound under the rotational limits of the optical system. Designed to survey, these images define lines and points It can be treated as diffraction. For example, the lens 106 has a HA (numerical aperture) of 0.02. In this case, flaws narrower than 25 microns can be measured.

This method consists of adjusting the Therefore, it can be easily used to measure surface flaws in all ranges by comparing them with predetermined standard flaws. It will be understood that it is possible.

Video signal or mechanical scanner instead of viewing on TV screen It is also possible to perform automatic image analysis using In addition, as described later, a single photocell It is also possible to create a time change signal with an intensity distribution that intersects with the image of the flaw. It is possible.

In the device as described above, the light source 101 is the tongue stem 1. It consists of a number of sources. However, by appropriately correcting the optical system, lasers can also be used. Can be used. Furthermore, the inclination of 108 is measured using a separate channel member. It is also possible to replace the surface 115 with a position sensing photocell.

If the slope of 108 is measured by the number of neighboring points intersecting the surface, then The resulting values may be integrated to obtain the surface geometry.

Additionally, a laser source can be used as a comparison flat between plate 107 and surface 108. It is also possible to form a diffraction pattern on the television camera 160 by using a diffraction pattern. child A conventional diffraction fringe counter is used to record the change in distance between the flat and the surface 108. method can be used.

If the scratches on the surface are due only to changes in phase difference, such as steps at the surface level. If so, it would be difficult to see clearly with the television camera 160. Pi By using a phase difference filter positioned above the hole image 124, Such a phase change can be converted into an amplitude change in a phase contrast microscope. .

Also, by using an absorbing disk in the pinhole 124, it is possible to use a dark-field illumination. It is also possible to employ conventional lighting techniques.

Another embodiment of this autopsy device is shown in FIG. In Figure 6, one light similar to Figure 1 is shown. Numbers indicate the same parts.

This figure 6 shows the elements 101, 102, 103, 104, 105, 106, 107.109゜110.112, 116 and 117 combined It is. Comparison surface 108 replaces retroreflector 208 and is a three-wave A comparative flaw scale 201 is provided between the long plate 107 and the V-lens 106. ratio The comparison surface 111 is replaced by a retroreflector 211, and the lens 109 and three-wave plate 11 A test lens 200 is provided between the two. Pinhole 104 and eccentricity Another lens 206 is provided between the optical beam splitters 105 and A rotating polarizer 204 is provided in place of the bundle beam splitter 120.

In the embodiment of FIG. 6, the tungsten halogen lamp at the focal position of the lens 103 After reflection at the polarizing beam splitter 105, the beam 101 is reflected at the lens 1090 surface. Form an image within. The iris diaphragm 117 is located at the focal point of the lens 203, and the lens 109 on the plane of lens 200 at the focal point of lens 109 during testing. It is designed to be imaged. 104 is an aperture stop used to control the amount of light It is. After passing through the k-wave plate 110, the light transmitted by the lens 200 It hits the retroreflector 211, returns to the system, and rotates the polarizer 20 by the lens 112. 4 onto a television camera 116.

The other part of the light transmitted by the polarizing beam splitter 105 is 109 and the comparative scale 201 at its focus. Light transmitted through scale 201 passes through the 3-wave plate 110 and hits the retroreflector 110, inverting the system to 3 An image of the scale 201 is formed on the television camera 116. Same as the mode shown in Figure 1. Similarly, polarizer 117 protects the light transmitted for the test and comparison channels (i.e., The elements from lens 109 and lens 106 are rotatable to make them equivalent. In addition, the polarizer 204 disturbs this balance depending on the measured amount and causes the lens 200 to It is used to equalize the diopter of the test scratch on the scale 201 and the comparison scratch on the scale 201. Ru. The four-wavelength plates 107 and 110 are used to capture the image of the scratch on the lens 200 and the scratch on the scale 201. can be rotated to maximize the intensity of each image.

Figures 4-A to 4-D show etching of rectangular long grooves on the surface of the glass substrate. The diopter of each of the four British standard scratches formed by Show what you have. The width and depth of this scratch is specifically indicated in the diopter range of approximately 10 to 1. However, it is as follows.

Wound dimension Depth (microns) Width (microns) X　O,02316,O AO, lower 8 16.9 B O, 01516-O CO,5217,1 Figures 5-A to 5-c show DIN O,0 placed vertically in the center of the screen. The TV image screen when measuring 10 scratches is shown.

For internal comparison scratches, two vertical parallel lines are placed between the scratches to be measured. Form the scale as used in automatic collimators equipped with

In Figure 5-B, the diopter of the DIN scratch and the scale are equal. Figure 5-A and Figure 5 Figure 5-c shows the polarizer 204 at 90°±5° from the exact position shown in Figure 5-B. Indicates that the diopter differs when rotated.

This equipment does not allow persons skilled in the art (and operators to Surface flaws can be measured continuously. In this method, the polarizer 117 is roughly adjusted. by placing a three-wave plate between the lens 206 and the surface to be tested. A method of measuring scratches on reflective surfaces and thin films has been adopted. Diamondta on a wide range of surfaces, including surfaces created by polishing, etching and conventional polishing. can be tested.

FIGS. 6 to 8 show still other embodiments of the present invention.

With respect to the devices described above, the use of polarizers may be undesirable in some cases.

For example, light with a large cone angle is required to illuminate a surface with a small radius of curvature. In some cases, a relatively large diameter light is required when examining contact lenses, etc. This is the case. Also, when changing the angle of incidence, if polarized light is used, surface reflection There are various problems.

The apparatus of FIGS. 6-8 uses a split aperture beam splitter. Solve these problems by 15 This is what I did.

In a general sense, two different biases passing through the test and comparison scratches respectively Instead of using a light beam, we use two horn normal light beams, and furthermore, these two A device is provided that changes the intensity of the beams so that the total sum remains the same but differs from each other.

As in the device described above, the two combined beams are observed or measured, and this By changing the relative intensities of these beams, the background illumination of the combined beams is Although always the same, the contrast between the two scratches changes.

Referring to FIGS. 6 to 8, the light from the tungsten halogen lamp 1 is diffused. It is partially scattered by the condenser lens 3 and onto the convex lens 4. focused. This convex lens 4 converts the image of the aperture 5 into an inclined parallel plate microphone self-meter. -6 to a predetermined position along the axis between the inclined plate 6 and the beam sinter 7. Therefore, it is formed at a position along the NS axis. Regarding opening 5, see Figure 7. It is illustrated in detail. As understood from FIG. 7, the opening 5 is long in the direction of the arrow. It consists of a rectangular opening 19 located across the square plate 20.

The beam splitter 7 is shown in detail in FIG.

As is clear from FIG. 8, this beam splitter 7 has an elliptical aperture 8 and It consists of an elliptical mirror surface 22. It is clear from Figure 6 that these are elliptical. This is because, as shown in white, the Sugeritter 7 forms an angle of 45° with the optical axis. light As far as the axially passing beam is concerned, the aperture 8 and the mirror surface 22 are annular. Ma , and Figure 8 shows the beam slits to show the relative positional relationship with respect to the optical axis. A projected view of the rectangular quantity [ ] 19 and the rectangular plate 2o in the tar 7 is shown.

If the aperture 5 is located at the focal point of the convex lens 4, the image of the aperture 5 will be formed at infinity. On the other hand, where should the convex lens 4 be located between the aperture 5 and the center of the beam splitter ~7? If the distance between the aperture 5 and the beam splitter 7 is 4, which is the focal length of the lens 4, If multiplied, the image of the aperture 5 will be formed on the beam splitter 7. . Compensate for different optical powers in combination with different radii of curvature of the surface to be examined Therefore, it is necessary to move the convex lens 4.

The light transmitted by the elliptical aperture 8 located at the focal point of the lens 9 is transmitted to the surface 1 to be examined. irradiate o. In this case, the surface 10 is located at the opposite focal point of the lens 9. inspection Light from the surface 10 to be viewed passes through the lens 9 and is reflected at the back of the beam splitter 7. total reflection by the lens 11 with the beam splitter located at its focal point. on the television camera 12 through the mirror 16 or directly on the photomultiplier 15. An image is formed on a pinhole 14 located in the plane. In such a case, a small amount of surface 1o The tilt prevents all the light from going in the opposite direction through the elliptical aperture 8. Considering that, the output of the television camera 12 is the area illuminated on the surface 10. can be used for autopsy.

Alternatively, since the surface 10 is perpendicular to the optical axis NS, the photomultiplier arm Output is used to record microscopic variations in reflection due to defects such as scratches on the surface 10. It can be used.

A preferred method of examining a generally spherical surface by reflection is described in our patent. According to the scanning mechanism disclosed in Application No. 8307348.

A portion of the light entering the beam splitter 7 is reflected along the ETV axis and focused A beam splitter 7 at a point and an inner comparison plate 17 at its sub-focal point. incident on the lens 16. A television camera is used to capture the light that is reflected back from the comparison section 17. When used, light from the surface 10 to be examined will be added.

When using a television camera, the mirror 13 is placed in the beam and manual irradiation operation is required. may be used to measure surface flaws. As already explained, the comparison section 17 and the test The total luminous flux reaching the television camera 12 from the scratch 10 on the scratch-free surface is maintained at a constant level similar to a given point, but with relative light intensities from the two scratches. The diopter of the comparative and test scratches is the same as that of the preferred example of the invention described above. It must be changed so that it is corrected.

The relative intensity of light from the comparison and test scratches is similar to that of a medium-toned dark (rust). btral d-ensity voetLgg) and lens 168 The adjustment I- is obtained by controlling the aperture diameter of the lens 9. However, the surface A suitable device for changing the intensity of light passing through the aperture 5 and the comparator 17 is the aperture 5, the inclined It has a plate 6 and a beam splitter 7.

The operation method is best (can be buried) as shown in FIG. Two corners 26 and 27 are formed by the intersection of the rectangular shapes. beam 26 hits the mirror surface 22 and is reflected to the comparison section 17. Beam 27 hits aperture 8. The relative intensities of these beams can be modified in two ways. Returning to FIG. 7, the rectangular plate 20 can be aligned by sliding it laterally. It is useful to globally increase the dimensions of one beam relative to the other. It is Noh. (However, the overall dimensions of the beam will change. Na~・. Also referring to FIG. 8, this effect shows that the inner edge 29 of the beam Move the inner edge 60 of the beam 27 from the right side to the left side with the V puff. If you move this edge 29.30 to the right, the beam will be The beam 26 becomes smaller, and the beam 27 passes through the dog 108 for autopsy. A large amount of light reaches the surface to be exposed.

However, the plate 20 is moved by rotating the tilting block l/-)/). Also, the beam passing through the plate 6 is accurate since the plate 6 is relative to the optical axis If it forms an angle of U 90', it will remain coaxial, but if the play toro is In a tilted position, the beam will shift laterally. Korenyo19 The image of the aperture 5 crossing the beam splitter 7 having a similar effect is effectively Moving. That is, if the inclined plate is rotated once in one direction, the surface 10 is A part of the beam 27 increases 1~, and is reflected by the mirror 8 and reaches the comparative scratch 17. 6 will be partially reduced. In this way, the image formed by the television camera 12 The resulting image will have the same relative strength as the comparison scratch and the surface 10"2/6 as described above. You can see it at

The techniques described herein reduce the cost of inspecting and measuring various surfaces. becomes possible.

The main characteristics of the ship are fast autopsy, non-contact, and surface scratches on a given area.1. optical clarity It can be measured with Cold-made or plated, the surface has a rough surface 0) It is possible to perform an autopsy. , and this surface can have virtually any radius of curvature. This technology can also be applied to the following fields: electronic optics, Engineering and surface 4♀ research.

Although we have discussed surface scratches here, the same applies to devices inside transparent materials. It can be inspected by law. In this case, it passes through the substance and is reflected from the back surface of the substance. The light passes through the material again and is detected by the light that returns into the device from the back of the material. It would be necessary to perform fortune-telling.

In addition to removing scratches, it is also possible to inspect images other than scratches, especially in the form of No. 6Nb shown in Figure 8. Use 1 - Obtain. For example, -〇 beam is reflected by mirror surface 22, and other beams are opened. Replace the light from two light sources with mirrors, such as through the mouth 8, the surface 10 and the comparative scratch 17. . Such a device can be used to determine the comparative intensity of grass and other light sources.

According to the present invention, instead of the traditional slow method of visual needle autopsy, , a fast computer-controlled inspection using the scanners and sensors mentioned above. By replacing it with , automation becomes extremely easy.

The apparatus and method of the present invention are useful for determining cell density in microbiotechnology. It can also be used for

smell Joheki (Contents (: No change) (Shisho courier/No support) Engraving (Contents) 3 No death) Sign table Showa 60-50027t5 (8) 20 029 Procedure supplement, TE letter (method) %formula% 1.Display of the incident PCT/GB83100332 2. Name of the invention Inspection equipment and method ), the person making the correction Relationship to the incident: Patent applicant 5. Date of amendment order November 27, 1982 (Shipping date) 6 Target of correction Taman visit ;! : report,

Claims (1)

[Claims] 1. Mechanism for generating two optical signals, defects to be inspected in one of the optical signals and the other is affected by the reference defect. Mechanism for placing defects and reference defects, defects to be inspected and reference defects A mechanism for comparing these two optical signals after each has been affected by a defect. , and the light intensity due to parts of the two optical signals that are not affected by the above two defects. received by the comparator so that the sum is substantially constant. and a mechanism for changing the intensity of one of the optical signals. A device for comparing the defects in a standard defect with a reference defect. 2 Contains a mechanism to equalize the intensities of two optical signals in the absence of defects. An apparatus according to claim 1. 6. In use, the comparator combines two optical signals into a single signal for inspection. Apparatus according to claim 1 for providing a single image. 4. The mechanism for changing the intensity of the optical signal is the mechanism for obtaining polarized light, the polarization of the polarized light A mechanism for changing the angle and a polarizing beamspring for splitting the polarized light into two optical signals. 7. A device according to claim 1 or claim 6 for emitting from a liter. 5. The mechanism for changing the intensity of the optical signal is a mechanism for providing a light beam, and a mechanism for changing the intensity of the optical signal. A mechanism for splitting and giving two optical signals (beam splitter), the beam splitter By relatively moving the splitter and the beam, the ratio of the optical beams is changed and each optical signal is 2. A device according to claim 1, comprising a mechanism for forming. 6. The beam splitter consists of a mirror and an aperture, and a part of the beam that hits the mirror is It gives one optical signal, and some of the beams passing through the aperture give another optical signal. 5. The device according to claim 5. B. The beam splitter and the mechanism for moving the beam relatively The claimed invention consists of an optically transparent block rotatable about an axis intersecting the The device according to scope item 6. 8. Process of obtaining two optical signals, defect to be inspected in one of the optical signals during inspection to be affected by the defect, and use the other second optical signal as a reference. The process of causing the two optical signals to pass through a defect so as to be affected by the defect, The process of combining, the process of inspecting the combined optical signal, the defects to be inspected and the reference The total intensity of the parts of the two optical signals that are not affected by defects in the until the image of the defect to be inspected and the image of the reference defect have the same intensity. Alternatively, the intensities of the two optical signals may be varied until they become contrasting or at a predetermined ratio to each other. a predetermined defect and a reference defect characterized by How to compare. 9. In the absence of defects, the intensities of the two optical signals are at most 23 9. The method of claim 8, which is initially equivalent. 10. A polarized light source, a mechanism for changing the polarization angle of the polarized light, and a mechanism for changing the polarization angle of the polarized light. Polarizing beam splitter for dividing into 5 surfaces to be inspected and reference material a defect on the surface to be inspected, and one of the two optical signals is affected by the defect on the surface to be inspected. a mechanism for causing the other optical signal to be influenced by the defect that is to be the reference; and Compare these two optical signals after they are affected by these defects. Comparison of surface defects characterized by a mechanism for equipment for 11.Reflect the two optical signals and return them to the polarizing beam splitter. The device according to claim 10 is provided with a reflection mechanism for combining the numbers. Place. 12. The surface to be inspected is a reflective surface, which reflects the optical signal and creates a polarized beam splitter. The device according to claim 10 or 11. 16. The two optical signals are reflected by the reflection mechanism and returned to the polarizing beam splitter. An apparatus according to claim 10 or 11. 14. The device according to claim 13, wherein the reflection mechanism comprises a retroreflection mechanism. 15. Install a focusing beam splitter so that the two combined optical signals pass through. , the focusing beam splitter splits the two combined beams to form a central spot. Contains a conical mirror surface on which a portion of the signal is focused, and the remainder of the two combined optical signals. The relative movement of the part with respect to the axis is inclined to the surface to be inspected. An apparatus according to any one of claims 11 to 14. 16. As described above with reference to the accompanying drawings Figure 1, Figure 6, or Figures 6 to 8. Comparing the defect that should be the standard described in claim 1 in terms of quality with the surface defect. device for In the process of obtaining a polarized light source, the polarized light is passed through a polarizing beam splitter and divided into two In the process of dividing one optical signal into two optical signals, one optical signal is The optical signal passes through the defect and is applied so that the other optical signal is influenced by the defect that is to be the reference. The process of passing the defect, the process of combining and inspecting the two optical signals, and the process of passing the defect to be inspected. In cases where the defect and the standard defect have the same strength or a predetermined ratio. For example, the polarization angle is changed to compare the defect to be inspected and the defect to be the reference. A process of changing the relative intensities of two optical signals so that A method of comparing the surface defects to be used as a reference with the defects to be used as a reference. 18゜Comparison method between surface defects as described above and defects to be used as a reference.