JPH0933446A - Apparatus for inspecting surface defect - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance a surface defect-detecting accuracy in a surface defect- inspection apparatus. SOLUTION: The surface defect-inspection apparatus has a light projection device 2 for projecting light to a surface of an object 1, a first photodetecting device 3 for detecting the amount of light directly reflected at the surface of the object 1, a light-shutting device 4 having an inner face of a mirror structure for preventing scattering of light irregularly reflected at the surface of the object 1, a second photodetecting device 5 for detecting the amount of light irregularly reflected at the surface of the object 1, and a surface defect judgment device 6 for judging whether a surface defect of the object is good from a ratio of the amounts of light entering the first and second photodetecting devices 3, 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface defect detecting method and a surface defect inspecting device for judging whether or not a minute surface defect such as unevenness or scratches on an object is acceptable.

In recent years, in order to realize miniaturization and high functionality of information equipment, the density of various parts has been dramatically increased.
As a result, magnetic head suspensions, optical disks,
Precision components such as semiconductor wafers and liquid crystals have been miniaturized at an accelerating rate, and even a slight surface defect that has not been a problem in the past has significantly affected the quality.

Therefore, development of a surface defect inspection apparatus capable of detecting such surface defects with high accuracy is strongly desired.

[0004]

2. Description of the Related Art Conventionally, a method used in a surface defect device is to illuminate an object from an arbitrary position with a light projecting means,
The light receiving means is arranged at a position where the specularly reflected light can be detected, and the specularly reflected light is detected by the light receiving means. Then, the presence or absence of the surface defect of the object is determined from the change in the light amount.

[0005]

In the prior art, when there is a change in the reflectance due to the unevenness of the surface of the object (for example, when the light absorptance changes due to the difference in color tone), it is detected by the light receiving means. In some cases, the amount of light changed and a target object that was a good product was determined to be a defective product. Further, when the defect is minute, the change in the amount of light to be detected is small, so that the defective object may be determined as a good product.

The present invention prevents such an erroneous determination,
It is an object of the present invention to provide an apparatus that detects surface defects accurately and accurately.

[0007]

FIG. 1 shows the principle of the present invention. 2 is a light projecting device that irradiates the surface of the target 1 with light, and 3 is a first that detects the specularly reflected light reflected at the inspection point 10.
, A second light receiving device 5 for detecting diffusely reflected light,
Reference numeral 4 is a light-shielding device for preventing the light diffusedly reflected on the surface of the object 1 from being dissipated and preventing the detection power from being lowered due to the influence of ambient light, and 6 is the detection in the first and second light receiving devices 3 and 5. It is a surface defect determination device that determines the presence or absence of a surface defect from the ratio of the amount of light.

The object 1 is held on a moving table 8 controlled by a drive controller 80, and a surface defect judging device 6 is provided.
The quality of each part is determined by, and the operation of the entire surface defect inspection apparatus is controlled by the overall controller 9.

[0009]

In the first aspect of the invention, the surface of the object 1 is irradiated with the inspection light from the light projecting device 2, and the reflected light from the surface is detected by the first and second light receiving devices 3 and 5. The light amount detected by the first and second light receiving devices 3 and 5 is compared by the surface defect determination device 6, and the quality is determined based on the ratio.

When the amounts of light detected by the first and second light receiving devices 3 and 5 are A and B, respectively, | A−B | / (A + B)
If x100 is found and is smaller than the judgment value K obtained in advance by means such as an experiment or a simulation, it is judged as defective because the surface of the object 1 has a change in unevenness.

The effectiveness of the present invention with respect to the conventional method in which A is determined and when it is smaller than the judgment value K'obtained by the same means as described above is defective, the irregular reflection causes a considerable amount of irregular reflection than a flat state. The point is that the amount of light detected by the second light receiving device 5 is increased, and it is easy to determine that the defect is defective in the case of a surface having a reflectance different from that of a normal surface even if it is not a defect in the conventional method. In the present invention, which determines quality based on the ratio of the irregular reflection light amount and the regular reflection light amount, since the light amount ratio is almost the same even if the reflectance is different, the above defects can be prevented and defects such as minute scratches and irregularities can be prevented. Can also be detected.

A light projecting device 2 according to a second aspect of the invention.
Is a minute laser spot illuminating device, and a photomultiplier is used as at least the second light receiving device 5. With such a configuration, the accuracy of the device itself is improved, and the inspection of the entire apparatus with higher accuracy becomes possible. By increasing the light-collecting ability of the second light-receiving device 5, the efficiency of capturing irregularly-reflected light is increased and the overall inspection accuracy is improved.

According to the third aspect of the invention, there is provided a structure for preventing disturbance light from entering the light shielding device 4 when the object 1 is covered with the light shielding device 4. A soft roller 40 that rolls on the object 1 is attached to the light shielding device 4, and even when the light shielding device 4 and the object 1 are relatively displaced, a gap between the surface of the object 1 and the light shielding device 4 is provided. Is blocked by the soft roller 40, and disturbance light from the gap is prevented from entering the shielding device. Further, by using the soft roller 40, it is possible to prevent the surface of the object 1 from being damaged when rolling on the surface of the object 1.

In the invention described in claims 4 and 5, there is provided a first light receiving device 3 in which the influence of ambient light is prevented. That is, in the invention of claim 4 shown in FIG.
A bandpass filter 31 that transmits only the irradiation light of the light projecting device 2 is arranged in front of the photoelectric conversion unit 30. The band-pass filter 31 prevents only disturbance light from entering the photoelectric conversion unit 30 by transmitting only the irradiation light from the light projecting device 2, and contributes to improvement in measurement accuracy.

In the invention of claim 5 shown in FIG. 3B, a condenser lens 32 having a focal length f and a pinhole 33 are arranged in front of the photoelectric conversion section 30 of the first light receiving device 3. . The distance between the pinhole 33 and the condenser lens 32 is equal to the focal length f of the condenser lens 32, and the specular reflection light on the surface of the object 1 passes through the condenser lens 32 and the pinhole 3
3, and further enters the photoelectric conversion unit 30. Due to the presence of the condenser lens 32 and the pinhole 33, only the specularly reflected light is focused on the condenser lens 32 and then enters the first light receiving device 3 through the pinhole 33. The disturbance light is prevented from entering the photoelectric conversion unit 30 of the light receiving device 3.

In the invention described in claims 6 and 7, a modification of the second light receiving device 5 is shown. Efficiently receiving diffusely reflected light having a smaller amount of light than that of specularly reflected light is effective for improving inspection accuracy, and the second light receiving device 5 according to the invention of claim 6 It is formed by attaching a photodiode array to the surface to be removed, and in the invention described in claim 7, the pin photodiode is formed to extend over the entire surface except the upper part of the sphere.

In the invention of claim 8 shown in FIG. 4,
The light projecting device 2 is movable along the irradiation light path to the surface of the object 1. As a result of the position of the light projecting device 2 being automatically corrected so that the amount of specularly reflected light in the first light receiving device 3 becomes a peak, the focus of the irradiation light from the light projecting device 2 is always an inspection point on the surface of the object 1. Since the value of 10 is satisfied, accurate pass / fail judgment is performed.

In the invention described in claims 9 to 11,
A configuration effective in preventing overflow in the first light receiving device 3 is provided. That is, in the invention according to claim 9 shown in FIG. 5, the light amount from the light projecting device 2 is automatically controlled so that the regular reflection light amount received by the first light receiving device 3 is always a constant amount. By controlling the irradiation light amount from the light projecting device 2 by voltage or current so that the regular reflection light amount becomes constant, it is possible to prevent the regular reflection light from exceeding the light amount range that can be received by the first light receiving device 3. As a result, accurate measurement is possible.

In the invention of claim 10 shown in FIG. 6, the amount of specular reflection light is monitored by detecting the amount of light in the first light receiving device 3, and the PLZ is provided in the preceding stage of the photoelectric conversion section 30.
A T shutter 34 is arranged. PLZT shutter 34
Is capable of continuously controlling the light transmittance by controlling the applied voltage, and when the incident light quantity exceeds the light quantity that can be received by the photoelectric conversion unit 30, the PLZT shutter 3
The light transmittance of No. 4 is continuously controlled, and the amount of light received by the first light receiving device 3 is kept constant.

In the eleventh aspect of the invention, the adjustment of the light amount in the first light receiving device 3 is performed by selecting the rotation variable ND filter 35. The rotation variable ND filter 35 is formed by arranging a plurality of ND filters having different transmittances on the same circumference, and rotating a plate holding the filters to block the optical path by an arbitrary ND filter to transmit a light transmission amount. Is controlled.

In the twelfth aspect of the invention shown in FIG. 8, an effective structure is provided for directing the first light receiving device 3 to the measurement point of the object 1. That is, the first light receiving device 3 includes a half mirror 36 arranged on the optical path of specularly reflected light on the surface of the object 1, and a CCD camera 37 that captures the light reflected by the half mirror 36. CCD
By determining the position of the specular reflection light incident on the first light receiving device 3 from the image information of the camera 37, and automatically correcting the position on the first light receiving device 3 side based on the position information of the specular reflection light, Accurate capture of specular reflection light is possible.

In the thirteenth aspect of the invention shown in FIG. 9, the light projecting device 2 is constituted by using a laser slit illuminating device, and line CCDs are used as the first and second light receiving devices 5.
A sensor is used. By using the laser slit illuminator, it is possible to inspect one line at a time and the inspection efficiency is improved.

In the fourteenth and fifteenth aspects of the present invention, there is provided a laser slit illuminating means for obtaining a stationary linear beam which is less affected by diffraction. That is, FIG.
In the fourteenth aspect of the invention shown in (a), the laser slit illuminating means comprises a semiconductor laser 20, a beam expander 21, an optical slit 22, and a slit reduction imaging optical system 23. By passing the light from the beam expander 21 through the optical slit 22 having a large slit width, the influence of the diffraction of the light is reduced, and the influence of the diffraction is prevented by narrowing the light in this state by the reduction imaging optical system. It

In a fifteenth aspect of the invention shown in FIG. 10 (b), a laser slit illuminating means which does not use the optical slit 22 is provided and is constituted by a semiconductor laser 20, a slit imaging optical system 23 and a concave cylindrical lens 24. To be done.

For the laser slit illumination light, not only a stationary type but also a flying beam can be used.
In the sixteenth aspect of the invention shown in (a), a scanning beam is formed by the galvano mirror 25, and in the seventeenth aspect of the invention shown in FIG. 11 (b), the polygon mirror 26 forms a scanning beam.

In the eighteenth aspect of the present invention shown in FIG. 12, in order to further enhance the surface defect detection power, the light projecting device 2
Then, a plurality of sets of the first light receiving device 3 are arranged, and the pass / fail judgment is performed by calculating the ratio of the received light amounts of the specular reflection light and the diffuse reflection light of all of them.

Further, in the invention according to claim 19 shown in FIG. 13, the arrangement angles of the light projecting device 2 and the first light receiving device 3 can be automatically changed at the same time, and the light projecting device 2 and the first light receiving device 3 can be changed. An electric slit 7 is added to the front stage of the device 3.

The light projecting device 2 is capable of irradiating the inspection point 10 from various angles, and the first light receiving device 3
Is configured to move to a position corresponding to the specular reflection angle from the inspection point 10. The pass / fail judgment is performed by calculating the total amount of received light of specular reflection light and diffuse reflection light from the target surface at various irradiation angles, and by calculating the ratio, it is possible to further improve the detection capability of surface defects. become.

In the invention as set forth in claim 20 shown in FIG. 14, there is provided a shading device 4 which is advantageous for efficient capture of diffused reflection light. That is, the light shielding device 4 is formed in a semi-elliptical spherical shape, and one of the two focal points of the ellipse is placed at the point where the optical axis of the light projecting device 2 and the target surface intersect, and the second focal point is located at the second focal point. The light receiving center of the light receiving device 5 is set.

[0030]

FIG. 2 shows a first embodiment of the present invention. In the figure, 8 is a moving table such as an XY table, 80 is a drive control device for controlling the moving speed, moving direction, etc. of the moving table 8. The inspection object 1 is placed on the moving table 8 by a fixing means (not shown). Placed and fixed.

Reference numeral 4 denotes a light-shielding device arranged on the moving table, which is arranged so as to cover the upper surface of the object 1.
The illustrated light shielding device 4 is formed in a box shape,
A mirror surface is formed on the inner surface. The shading device 4 having a mirror surface is formed by attaching a mirror body inside the housing or assembling the shading device 4 with a plurality of mirror bodies.

A light projecting device 2 is arranged on the side of the light shielding device 4, and the irradiation light from the light projecting device 2 is transmitted through a through hole 41 formed in one side wall of the light shielding device 4 to the light shielding device 4. The inspection point 10 of the object 1 held inside the movable table 8 is guided at a predetermined angle θ. As the light projecting device 2, a minute laser spot illuminating device using a laser oscillator or the like can be used.

In order to receive the specularly reflected light of the observation light at the inspection point 10, the first light receiving device 3 is arranged at a position symmetrical to the light projecting device 2 with respect to the light shielding device 4, and the inspection point 10 is also provided. A second light receiving device 5 for receiving the diffusely reflected light in the above is provided in the light shielding device 4. Silicon photodetectors can be used for the first and second light receiving devices 3 and 5, but it is also possible to amplify the amount of detected light by using a photomultiplier.

FIG. 3A shows the first light receiving device 3, which is a photoelectric conversion part 30 such as a silicon photodetector, a condenser lens 32, and a bandpass which transmits only the irradiation light of the light projecting device 2. The disturbance light is blocked by the band-pass filter 31, and only the specular reflection light indicated by the arrow in the figure enters the photoelectric conversion unit 30 to measure the light amount.

The first light receiving device 3 shown in FIG.
In the preceding stage of the photoelectric conversion unit 30, a condenser lens 32 having a focal length f and a pinhole 33 body arranged at the focal position of the condenser lens 32 are arranged in parallel with the condenser lens 32. Except for the specularly reflected light from the object 1 to be incident, it is blocked by the pinhole 33 formed in the center of the pinhole 33 member, so that the disturbance light is prevented from entering the photoelectric conversion unit 30.

Further, increasing the light collection efficiency of the second light receiving device 5 is effective for improving the inspection accuracy. As described above, in addition to using the photomultiplier for the second light receiving device 5, The light receiving device 5 is formed into a rectangular parallelepiped or a polyhedron such as a cube, and a photodiode array is attached to all surfaces other than one surface to which wiring for signal extraction is connected, or the second light receiving device 5 is formed into a spherical shape. However, it is possible to attach pin photodiodes to all surfaces other than one point where wiring for signal specifications is connected, and to detect light from all directions.

Reference numeral 42 denotes an ambient light blocking device, which is a light projecting device 2
Is provided in order to prevent disturbance light from being mixed into the irradiation light from the light source and the reflected light from the inspection point 10, and the optical path from the light projecting device 2 to the light shielding device 4 and the light shielding device 4
To the first light receiving device 3 and a box body 43 for covering the optical path of the specularly reflected light, and a soft roller 40 for closing the gap between the surface of the object 1 and the light shielding device 4. As the soft roller 40, synthetic rubber, soft synthetic resin, or the like can be used.

Therefore, in this embodiment, the light emitted from the light projecting device 2 illuminates the inspection point 10 of the object 1 through the through hole, and the irregularly reflected light is reflected directly or repeatedly by the mirror surface in the shielding device. While receiving the second light receiving device 5
The light amount is captured by and is measured. On the other hand, the light specularly reflected by the inspection point 10 passes through the other through hole of the light shielding device 4 and is captured by the first light receiving device 3 to measure the light amount thereof. The quality of the surface condition at the inspection point 10 is determined.

The inspection point 10 is changed by driving the moving table 8, and the soft roller 40 provided on the light shielding device 4 moves on the object 1 by driving the moving table 8, that is, by moving the object 1. While rolling, the relative displacement between the shading device 4 and the object 1 is allowed, and the entry of ambient light into the shading device 4 is prevented.

The movement control device 8 is used to inspect the surface of the object 1.
The overall control device 9 controls the surface defect determination device 6, the drive control device 80, and the entire device such as the light projecting device 2 while driving the moving table 8 by 0.

FIG. 4 shows a second embodiment of the present invention. In the following description, the same components as those in the above-described embodiment are designated by the same reference numerals in the drawings, and the description thereof will be omitted. In this embodiment, the irradiation light from the light projecting device 2 is focused on the object 1.
This is a modification that is effective for increasing the inspection accuracy in accordance with the inspection point 10 of 1. The projector 2 advances and retracts the projector 2 with respect to the inspection point 10 of the object 1 with the incident angle θ kept constant. In order to be able to do so, it is held on a light projecting device moving table 271 which moves along the optical axis of the light projecting device 2. The operation of the light projecting device moving table 271 is controlled by the light projecting device drive control device 272, and the light projecting device 2 moves from the light projecting device 2 to a position where the amount of light detected by the first light receiving device 3 becomes maximum. The irradiation light is automatically controlled so as to focus on the inspection point 10 of the object 1.

FIG. 5 shows a third embodiment of the present invention. In this embodiment, the amount of specularly reflected light from the object 1 does not exceed the amount of light that can be received by the first light receiving device 3,
In particular, it is a modification that is effective when the target object 1 is changed or when the target object 1 having greatly different properties locally is inspected.
The output value from the first light receiving device 3 is constantly monitored, and the light amount control device 28 is fed back so that the output value becomes constant. The amount of irradiation light in the light projecting device 2 is adjusted by controlling the current or the voltage.

FIG. 6 shows a modification of FIG. This modification prevents the overflow in the first light receiving device 3 by directly adjusting the incident light amount of the specularly reflected light from the object 1, and in the preceding stage of the photoelectric conversion unit 30 of the first light receiving device 3. ,
A PLZT shutter 34 is arranged in which the light transmittance can be continuously controlled by controlling the applied voltage. The light transmittance of the PLZT shutter 34 is controlled by the shutter control device 340, and the shutter control device 340 controls the PLZT shutter 34 by the output from the first light receiving device 3 which is constantly monitored.

In this case, instead of the PLZT shutter 34, as shown in FIG. 7, a plurality of Ns having different light transmittances are used.
D (Neutral Density) filter 35
Variable rotation type ND with 0, 350 ...
It is also possible to use the filter 35.

FIG. 8 shows a fourth embodiment of the present invention. This embodiment is a configuration effective for always directing the first light receiving device 3 to the inspection point 10 of the object 1, and the light shielding device 4
The wall surface on the first light receiving device 3 side is a light transmission wall surface 44. The first light receiving device 3 includes a photoelectric conversion unit 30, an electric slit 38 whose slit position is controlled by the slit control device 380, and which transmits only specularly reflected light to the first light receiving device 3, and a half mirror 36. , A CCD camera 37 for capturing the reflected light from the half mirror 36,
The output from the CD camera 37 is processed by the image processing device 370 to determine the position of the specularly reflected light incident on the first light receiving device 3.

The above first light receiving device 3 and light projecting device 2
Can be moved on a circular orbit around the inspection point 10 of the object 1 by the moving device 39, and by controlling the position of the first light receiving device 3 based on the output from the image processing device, The first light receiving device 3 is located on the optical path of specularly reflected light.

FIG. 9 shows a fifth embodiment of the present invention. In this embodiment, it is possible to collectively inspect the inspection points 10, 10, ... On one line.
As a laser slit illuminator is used as
Line CCD sensors are used for the first and second light receiving devices 3 and 5.

The laser slit illuminator is shown in FIG.
, The semiconductor laser 20, the beam expander 21, the optical slit 22, and the slit imaging optical system 2 are shown in FIG.
3 and the semiconductor laser 20.
After the beam width of the laser beam from is expanded by the beam expander 21, a slit having a large slit width with little influence of diffraction is obtained by the optical slit 22, and further, the slit image forming optical system 23 narrows down the laser slit light. can get.

The laser slit device shown in FIG. 10 (b) obtains a static linear beam without using the optical slit 22, and includes a semiconductor laser 20, a slit imaging optical system 23, and a concave laser beam. Cylindrical lens 24
The slit light focused by the slit imaging optical system 23 is expanded by the concave cylindrical lens 24 to obtain laser slit light.

In the inspection using these laser slit illuminators, for example, the quality of the line to be inspected is determined by the first and second inspections.
It is possible to determine the defect point on the line from the distribution of the amount of light received in each cell in the CCD sensor of the first light receiving device 3 by making a determination from the ratio of the total amount of light in the light receiving devices 3 and 5.

FIG. 11 shows a modification of the laser slit illuminating device when a scanning beam is used as irradiation light. The laser slit illuminating device shown in FIG. 11 (a) includes a semiconductor laser 20 and a slit imaging optical system 23. , A collimator lens 29, and a galvanometer mirror 25. In the laser slit illuminator of FIG. 11B, a polygon mirror 26 is used instead of the galvanometer mirror 25.

FIG. 12 shows a sixth embodiment of the present invention. This embodiment is a modification for further improving the reliability of the inspection, and the inspection point 10 is irradiated with the inspection light from two sets of the light projecting devices 2 and 2. On the other hand, on the opposite side of the light shielding device 4, two sets of first light receiving devices 3 and 3 are arranged to receive the specularly reflected light of each inspection light, and whether the object 1 is good or bad is the first.
This is determined by the ratio of the amount of light detected by the light receiving device 3 and the amount of light detected by the second light receiving device 5. Note that FIG. 12 shows the case where two sets of the light projecting device 2 and the first light receiving device 3 are used, but it is of course possible to use more than that.

FIG. 13 shows a seventh embodiment of the present invention. In this embodiment, electric slits 7 whose slit positions are movable are fixed to both side walls of the shading device 4, and correspond to the installation area of the electric slit 7 on the wall surface of the shading device 4 whose inner surface is a mirror surface. The area to be formed is the half mirror surface 45.

On the other hand, the first light receiving device 3 and the light projecting device 2 can be moved on a circumferential orbit around the inspection point 10 by the moving device 39, and the light projecting device 2 can be moved along the above orbit. At the same time, while the first light receiving device 3 is positioned on the optical path of the specularly reflected light, irradiation and light reception are performed at various angles, and the total amount of light received by the first light receiving device 3 and the second light receiving device 5 is calculated. The quality is calculated and the quality is judged based on the calculated ratio.

In the above embodiment, the light shielding device 4
Although the box-shaped one is shown, as shown in FIG. 14, it is formed in a semi-elliptical sphere shape, the light receiving center of the second light receiving device 5 is placed at one focus position of the ellipse, and the other focus position is set. It is also possible to arrange the inspection point 10 so as to focus the diffused reflected light on the second light receiving device 5.

[0056]

As is apparent from the above description, according to the present invention, it is possible to improve inspection accuracy by eliminating defects such as erroneously determining defects even on a surface having a reflectance different from that of a normal surface. it can.

[Brief description of drawings]

FIG. 1 is a diagram showing the principle of the present invention.

FIG. 2 is a diagram showing a first embodiment of the present invention.

FIG. 3 is a diagram showing a first light receiving device.

FIG. 4 is a diagram showing a second embodiment of the present invention.

FIG. 5 is a diagram showing a third embodiment of the present invention.

FIG. 6 is a diagram showing a modification of FIG. 5;

FIG. 7 is a diagram showing a variable rotation ND filter.

FIG. 8 is a diagram showing a fourth embodiment of the present invention.

FIG. 9 is a diagram showing a fifth embodiment of the present invention.

FIG. 10 is a diagram showing a light projecting device.

FIG. 11 is a diagram showing a modified example of the light projecting device.

FIG. 12 is a diagram showing a sixth embodiment of the present invention.

FIG. 13 is a diagram showing a seventh embodiment of the present invention.

FIG. 14 is a diagram showing a modified example of the light shielding device.

[Explanation of symbols]

 1 Object 2 Projection Device 20 Semiconductor Laser 21 Beam Expander 22 Optical Slit 23 Slit Reduction Imaging Optical System 24 Concave Cylindrical Lens 25 Galvano Mirror 26 Polygon Mirror 3 First Light Receiving Device 30 Photoelectric Converter 31 Band Pass Filter 32 Condenser lens 33 Pinhole 34 PLZT shutter 35 Rotatable variable ND filter 36 Half mirror 37 CCD camera 4 Shading device 40 Soft roller 5 Second light receiving device 6 Surface defect determination device 7 Electric slit

Claims (21)

[Claims] 1. A light projecting device for irradiating the surface of an object with light, a first light receiving device for detecting the amount of light specularly reflected by the surface of the object, and an inner surface having a mirror structure, A light-shielding device that prevents the diffused reflection of light on the surface of the object, a second light-receiving device that detects the amount of light diffusely reflected on the surface of the object, and the first and second light-receiving devices. A surface defect inspection device having a surface defect determination device for determining the quality of a surface defect of an object from the ratio of the amount of light. 2. The surface defect inspection apparatus according to claim 1, wherein a minute laser spot illuminating device is used as the light projecting device, and a photomultiplier is used as at least the second light receiving device. 3. The surface defect inspection according to claim 1, wherein the shading device is equipped with a soft roller that rolls on the object to prevent the influence of ambient light entering through the gap between the shading device and the object. apparatus. 4. The bandpass filter for transmitting only the irradiation light of the light projecting device is arranged in front of the photoelectric conversion unit of the first light receiving device to prevent the influence of ambient light. The surface defect inspection apparatus according to. 5. The specularly reflected light on the surface of the object is guided to the photoelectric conversion portion of the first light receiving device through a condenser lens having a focal length f and a pinhole arranged at a distance f.
4. The surface defect inspection apparatus according to any one of 3 to 3. 6. The surface defect inspection apparatus according to claim 1, wherein the second light receiving device is formed by adhering a photodiode array to a surface of the polyhedron excluding the upper surface. 7. The surface defect inspection apparatus according to claim 1, wherein the second light receiving device is formed by arranging pin photodiodes all over the surface except the upper part of the sphere. 8. The light projecting device is movable along an irradiation optical path to an object surface, and the light projecting device is automatically corrected to a position where the amount of specularly reflected light in the first light receiving device reaches a peak. The surface defect inspection apparatus according to any one of 1 to 7. 9. The surface defect inspection apparatus according to claim 1, wherein the light amount from the light projecting device is automatically controlled so that the amount of light received by the first light receiving device is always constant. 10. The amount of specular reflection light is monitored by detecting the amount of light in the first light receiving device, and the amount of light received by the first light receiving device is set at a pre-stage of the photoelectric conversion unit so that the amount of light received is always constant. 9. The surface defect inspection apparatus according to claim 1, wherein the surface defect inspection apparatus is automatically controlled by the PLZT shutter arranged in. 11. The surface defect inspection apparatus according to claim 10, wherein a variable rotation type ND filter is used in place of the PLZT shutter. 12. The first light receiving device comprises a half mirror arranged on the optical path of specularly reflected light on the surface of an object,
A CCD camera for capturing light reflected by a half mirror is provided, the position of specularly reflected light is captured from an image by the CCD camera, and the position of the first light receiving device is automatically corrected to match the specularly reflected position. The surface defect inspection apparatus according to any one of 1. 13. The surface defect inspection apparatus according to claim 1, wherein a laser slit illuminating device is used as the light projecting device, and one line on the surface of the object is inspected collectively. 14. The surface defect inspection apparatus according to claim 13, wherein said laser slit illuminating means comprises a semiconductor laser, a beam expander, an optical slit, and a slit reduction imaging optical system. 15. The surface defect inspection apparatus according to claim 13, wherein the laser slit illuminating means comprises a semiconductor laser, a slit imaging optical system, and a concave cylindrical lens. 16. The laser slit illumination light is a laser beam scanned by a galvanometer mirror.
The surface defect inspection device according to the above. 17. The laser slit illumination light is a laser beam scanned by a polygon mirror.
The surface defect inspection device according to the above. 18. A surface defect of a surface defect is determined by arranging a plurality of sets of the light projecting device and the first light receiving device, calculating the ratio of the amount of received light of specular reflected light and diffused reflected light of all of them, and judging whether the light is defective. The surface defect inspection apparatus according to any one of claims 1 to 17, which enhances detection power. 19. A structure in which the arrangement angles of the light projecting device and the first light receiving device can be automatically changed at the same time, and electric slits are added in front of the light projecting device and the first light receiving device, respectively. The detection power of a surface defect is increased by obtaining the total amount of received light of specular reflection light and diffuse reflection light from a target surface at various irradiation angles, and calculating the ratio to determine whether the defect is good or bad. The surface defect inspection device described. 20. The light-shielding device is formed in a semi-elliptical spherical shape, and one of the two focal points of the ellipse is placed at the point where the optical axis of the light projecting device 2 and the target surface intersect, and another focal point is set. 20. By setting the light receiving center position of the second light receiving device so that all the diffusely reflected light is incident on the second light receiving device, the detectability of minute defects is enhanced. Surface defect inspection device. 21. The surface of the inspection object is irradiated with inspection light from a light projecting device to measure the amounts of specular reflection light and diffuse reflection light from the surface of the inspection object, and the ratio of the irregular reflection light amount to the specular reflection light amount is predetermined. A surface defect inspection method that determines that there is a surface defect when the value is higher than the value and determines that there is no surface defect when the value is lower.