JP2003315282A - Surface inspection unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface inspection unit that can detect a flaw on a specular surface of an object to be inspected with accuracy. <P>SOLUTION: This surface inspection unit is constituted so that the light 1a emitted from a point light source or a similar light source 4 may be projected upon the surface 2 to be inspected, by refracting the light 1a through a Fresnel lens 5 to a direction in which the light 1a is parallelly converged, and, at the same time, reflecting the refracted light 1a by a half mirror 6 and the light 1a reflected by the surface 2 is introduced to an image pickup means 10 provided at the converged spot of the light 1a. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface inspection apparatus for mainly inspecting scratches generated on an object to be inspected having a mirror-like surface such as CD, semiconductor wafer, DVD, MD and the like.

[0002]

2. Description of the Related Art Conventionally, various surface inspection apparatuses have been considered for inspecting scratches generated on an inspection object having a mirror-like surface such as a CD or a semiconductor wafer, and one of them has been considered. As shown in FIG. 23, there is known one in which a surface emitting illumination device uniformly illuminates the surface of an object to be inspected, and the reflected light is imaged to inspect for the presence of scratches.

[0003]

However, in the case where the surface to be inspected is a mirror surface, when the diffused light which is not parallel light and is emitted from a plurality of light sources is irradiated, the surface to be inspected is generated. In some cases, it may not be possible to carry out an effective inspection because the scratches and engravings become invisible. Specifically, as shown in FIG. 21, there is a problem that it is extremely difficult to detect scratches such as scratches in the form of thin lines 92 such as scratches and dot-like scratches 92 when the scratches are minute.

[0004]

SUMMARY OF THE INVENTION Therefore, according to the present invention, light emitted from a point light source or a light source close to the point light is refracted by a lens to be parallel light which is gradually converged, and the light is applied to a surface to be inspected. The image pickup means is arranged at a portion where the reflected light converges.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION That is, a surface inspection apparatus according to the present invention is for inspecting a scratch generated on a surface to be inspected having a mirror surface and reading a laser engraved mark, and is a point light source. Or a light emitting means having a point light emitting element which is a light source close to it, a Fresnel lens, a half mirror,
An image pickup means is supported by the main body of the apparatus, light is emitted from the light emitting means, and the light is refracted by the Fresnel lens to be light having a direction of converging close to parallel and refracted by the Fresnel lens. Light is reflected by a half mirror to irradiate almost the entire surface to be inspected, and the light reflected by the surface to be inspected is guided to an imaging means provided at a portion where the light converges. And

[0006] In such a case, since the scratched portion and the other portion are clearly separated by the light and dark, minute scratches such as lines and dots which cannot be found by the conventional surface inspection apparatus are surely detected. can do. This phenomenon is considered to be due to the following reasons.

That is, when the light having a converging property is applied to the mirror surface portion of the object to be inspected, the reflected image is gradually reduced and guided to the image pickup means as the light converges. On the other hand, the light applied to the portion where the scratch is formed is reflected in a direction different from the converging direction due to the fine unevenness of the scratch. Therefore, it is considered that the light reflected from the portion where the scratch is formed does not reach the image capturing means in the image capturing means, and the portion appears dark in the image captured.

On the other hand, CDs, semiconductor wafers, DVDs, MDs
In order to converge light that is close to parallel light to a comparatively large surface to be inspected, etc., it is necessary to lengthen the optical path considerably, making the size of the device realistic. Difficult to do. In order to effectively solve this point, it is preferable that the light reflected on the surface to be inspected is further reflected a plurality of times by a plurality of reflection mirrors provided inside and guided to the image pickup means. Further, since the Fresnel lens which is thin and has a short focal length and is inexpensive is used, there is an effect that it can contribute to the downsizing and cost reduction of the device.

It is desirable that an even number of reflection mirrors are provided in order to prevent the image taken by the image pickup means from being left / right or upside down from the real thing.

In order to easily adjust the image forming position and the visual field by flexibly responding to the change in the optical path length due to the difference in the installation position of the object to be inspected, the image pickup means is attached to and detached from a predetermined position of the apparatus main body. In the case where it can be fixed, a refracting lens is arranged on the optical axis and in the vicinity of the image pickup means so that the refracting lens can be slid along the optical axis. It is preferable that the image pickup means is provided so as to be movable along the optical axis of the light emitted from, or the image pickup means is provided so as to be movable along the optical axis of the light guided to the image pickup means.

As a concrete embodiment, the point light emitting element has a columnar light-transmitting body having a light guide surface at one end and a light-emitting surface at the other end, and irradiation light guides the columnar light-transmitting body. A plurality of LEDs or optical fibers arranged so as to be concentrated on the light surface are provided, and light is emitted from the light emitting surface. A light diffusing action is provided on the light emitting surface of the columnar light-transmitting body. The thing which provided the light diffusion part which runs can be mentioned.

For good surface inspection, the device body must be
It is preferable that a part or all of them is matt processed.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS <First Embodiment> A first embodiment of the present invention will be described below with reference to FIGS.

The surface inspection apparatus 1 shown in FIGS. 1 to 3 is for inspecting a scratch 92 generated on a mirror surface portion 2 which is an inspection target surface of an inspection object 98 such as a CD or a DVD, and is a main body of the apparatus. Casing 3, light emitting means 4, and total reflection mirror 7
A Fresnel lens 5, a half mirror 6, and a CCD camera 10 as an image pickup means.

The respective parts will be described in detail. The casing 3 has a rectangular shape, and a front plate 131 erected so that its long sides are vertical, and a pair of rear plates extending rearward from the long side parts of the front plate 131. Side plates 132 and these side plates 132
And a partition plate 133 installed between the side plates 132 so as to divide the internal space S formed by the front plate 131 into upper and lower parts of the first space S1 and the second space S2, and the side plate 132.
And a cover 134 covering the periphery of the cover from the outside. Therefore, the front plate side approximately half between the lower edges of the side plates 132 is not covered with the cover 134,
An opening 99 is formed in that portion. It should be noted that each of the above-mentioned members is subjected to black alumite processing which is a matte processing.

The light emitting means 4 has a columnar translucent body 42 having a light guide surface 43 at the tip and a light emitting surface 41 at the base end, and the emitted light is concentrated on the light guide surface 43 of the columnar translucent body 42. Point light source element 4A composed of a plurality of LEDs 44 arranged so as to
Is built in a stepped tubular casing 104, and is configured to emit the light 1 a from the light emitting surface 41. In this embodiment, a plate-shaped light diffusing plate portion 47 is superposed on the light emitting surface 41 of the columnar light-transmitting body 42 so that the light diffusing action is performed in that portion.

Further, the light emitting means 4 is provided in the first space S.
On the side opposite to the front side in 1, the side plate 132 is supported via the light emitting means support plate P1 in a posture in which the light emitting surface 41 faces downward, that is, in a posture in which the light 1a is emitted vertically downward. The light emitting means support plate P1 is provided between the side plates 132 and fixed so as to be slidable in the vertical direction. Specifically, the through groove 4 provided in the side plate 132 so as to extend vertically.
The screw B is inserted through the screw 6, and the screw B is screwed into a screw hole (not shown) provided at the side edge of the light emitting means supporting plate P1 to thereby attach the light emitting means supporting plate P1 and the light emitting means 4 to the optical axis. It can be moved vertically and fixed along 1b.

The total reflection mirror 7 is a plane mirror fixed at an angle of 45 degrees on the side opposite to the front plate in the second space S2, and the light emitted from the light emitting means 4 is directed in the downward direction of 90 degrees. The light 1a is changed in degree and travels horizontally toward the front plate side.

The Fresnel lens 5 is vertically erected in a posture parallel to the front plate 131 at approximately the center of the second space S2, and the light 1 reflected by the total reflection mirror 7
The optical axis 1b of "a" passes through the center of the optical axis 1b, and the light 1a which is refracted by passing therethrough is arranged in a position in which the light 1a has a direction of converging near parallel. The Fresnel lens 5 has
Maximum surface diameter to be inspected (100 m in this embodiment)
m) larger than that is used.

The half mirror 6 is a flat plate-like member that reflects almost half of the emitted light 1a and transmits the other half, and the opening 99 on the front plate side in the second space S2.
A total reflection mirror 7 above and in front of the Fresnel lens 5.
It is fixed in a posture parallel to, that is, at an angle of 45 degrees.

The CCD camera 10 is arranged in the first space S1 such that the lens is directed vertically above the half mirror, that is, the light 1a traveling from vertically below can be introduced into the camera support plate P2. Through the side plate 13
It is supported by 2. This camera support plate P2 is a side plate 1
It is installed between 32 and is fixed so as to be slidable in the vertical direction. Specifically, a screw B is inserted into a through groove 56 provided in the side plate 132 so as to extend in the vertical direction, and the screw B is inserted into the camera support plate P2. The camera support plates P2 and CC can be tightened by tightening the screw holes (not shown) provided on the side edge of the
The D camera 10 can be moved vertically and fixed along the optical axis 1b. Further, the CCD camera 10 is provided with a cord 57 capable of outputting a captured image and the like to the outside and a connector (not shown) at the tip thereof so that the image can be viewed on a display or the like. .

The operation of the surface inspection apparatus 1 described above will be described.

First, in use, an object to be inspected 98 such as a CD or MD is placed outside the casing 3 in such a posture that its mirror surface portion 2 faces the opening 99.

After that, when the light emitting means 4 is operated, the light 1a emitted from the light emitting means 4 spreads downward in the vertical direction, and after passing through the first through window M1 provided in the partition plate 133, It is reflected by the reflection mirror 7 and changes its traveling direction to the horizontal front.

Then, by passing through the Fresnel lens 5, the light 1a is refracted so as to be gradually converged.
The refracted light 1a is reflected by the half mirror 6, changes its direction so that a part of the light 1a travels vertically downward, passes through the opening 99, and the mirror surface portion 2 of the inspection object 98 installed outside the casing 3. Is irradiated.

Further, the light 1a irradiated on the mirror surface portion 2
Is reflected here and advances vertically upward, passes through the opening 99, the half mirror 6 and the second through window M2 provided in the partition plate 133, and gradually converges toward the CCD camera 10 in a converged state. It will be taken in in a state close to.

With this structure, the scratches 92
The light 1a applied to the portion where the scratches are formed is reflected in a direction different from the converging direction due to the fine irregularities of the scratches 92, so that the CCD camera 10 reflects the light 1a reflected from the portion where the scratches 92 are formed. The reflected image will be captured in the state where the is missing. Therefore, as shown in FIG.
The part where the mark is formed and the other part are clearly separated by light and dark, and a linear scratch 92 such as a scratch and a minute scratch 9 such as a dent that cannot be found by a conventional surface inspection device.
It becomes possible to reliably detect 2 as well. Further, not only scratches but also markings can be read clearly, and therefore it can be applied to the reading device.

Further, since the Fresnel lens 5 which is thin, has a short focal length, and is inexpensive is used, it can be suitably applied to those having a relatively large mirror image surface 2 such as a CD and a DVD.

On the other hand, in order to improve the above-mentioned detection accuracy, theoretically, the light emitting means 4 should be as close to a point light source as possible, and the light 1a thereof should be refracted to become light 1a which is as parallel as possible. However, if it is too close to the theory, the light 1a will not be taken into the CCD camera 10 due to a mounting error or distortion of the Fresnel lens 5, or a slight inclination or warp of the table on which the CD or DVD is placed. As a result, in the image projected on the CCD camera 10, the part without the scratch 92 may be dark.

Therefore, in the present embodiment, the light 1a emitted from the light emitting means 4 is diffused by the light diffusing section 47 to slightly increase the light emitting area. Due to this, mounting error or distortion of the Fresnel lens 5, or CD or DVD
It becomes possible to allow a certain amount of warp, tilt of the table on which the inspection object 98 is placed, and the like, which is extremely preferable in practical use.

Further, since the light emitting means 4 and the CCD camera 10 are slidable along the optical axis 1b, the difference in the installation position of the object 98 to be inspected and the shift of the image forming position due to secular change or the like can be facilitated. Can be adjusted.

Further, since the casing 3 is matt-finished by black alumite processing, light scattering inside the casing 3 can be suppressed and the above-mentioned effect can be made remarkable, and the reliability of the surface inspection apparatus 1 can be improved. Can improve the sex.

Furthermore, by using the surface inspection apparatus 1, it is possible to discriminate the printed characters M and the like applied to the mirror surface portion of the CD. The light radiated to the surface to be inspected is diffusely reflected by the printed characters M and the like, while it is reflected by the mirror surface portion where the printed characters M are not applied, while maintaining the convergence. This is because, as shown, the printed character M portion and other portions are clearly separated depending on the lightness and darkness, and the contrast of the printed state is clearly projected on the image pickup means such as a CCD camera. <Second Embodiment> Next, a second embodiment of the present invention will be described with reference to FIGS. The members corresponding to those in the first embodiment are designated by the same reference numerals.

The surface inspection apparatus 1 shown in FIGS.
The purpose is the same as that of the embodiment, and the casing 3, the light emitting means 4 disposed inside the casing 3, the Fresnel lens 5, the half mirror 6, and the three total reflection mirrors 7 and 8,
9 and a CCD camera 10 as an image pickup means.

The casing 3 has a pair of generally L-shaped upper side plates 33, a horizontal plate 34 arranged so as to straddle the lower end edges of the upper side plate 33, and the horizontal plates 34 hang down from the left and right ends thereof. The lower side plate 35, the rear plate 37 arranged over the rear end edges of the upper side plate 33 and the lower side plate 35, the upper cover 81 that can cover the upper side plate 33 from above, and the lower half front half of the lower side plate 35. And a bottom cover 82 which is L-shaped in side view and which can be arranged over the front end edge, and a bottom cover 83 which is arranged so as to straddle between the rear end portions of the lower end edges of the lower side plates 35. An opening 99 for exposing the inspection object 98 is provided in the latter half of the bottom surface, and the opening 9 is provided in the latter half of the horizontal plate 34.
An opening 97 is provided so as to be located above 9. Inside the light emitting means mounting chamber 11,
A mirror mounting chamber 12 and an imaging means mounting chamber 13 are formed. It should be noted that each of the above-mentioned members is subjected to black alumite processing which is a matte processing.

The light emitting means mounting chamber 11 is formed in the lower part of the front half of the casing 3, and is surrounded by the horizontal plate 34, the lower side plate 35, and the lid 82. Then, the light emitting means 4 is housed inside.

The mirror mounting chamber 12 is formed in the rear half of the casing 3, is located behind the light emitting means mounting chamber 11, and has a lower side plate 35, a bottom cover 83, and an upper side plate 33. It is surrounded by the rear plate 37. And inside it, three total reflection mirrors 7, 8, 9 and a half mirror 6
It houses and.

The image pickup means mounting chamber 13 is located above the light emitting means mounting chamber 11, and has an upper side plate 33 and an upper cover 81.
It is surrounded by the horizontal plate 34 and houses the CCD camera 10 inside.

The light emitting means 4 has a columnar translucent body 42 having a light guide surface 43 at the tip and a light emitting surface 41 at the base end, and the emitted light is concentrated on the light guide surface 43 of the columnar translucent body 42. The point light source element 4A including a plurality of LEDs 44 arranged as described above is provided, and the light 1a is emitted from the light emitting surface 41. Then, a plate-shaped light diffusing plate portion 47 is provided on the light emitting surface 41 of the columnar light-transmitting body 42, and the light diffusing action is performed in that portion. Further, the posture of the light emitting means 4 is set so that the emitted light 1a is directed toward the mirror mounting chamber 12 and the optical axis 1b thereof is horizontal in the front and rear direction. Further, in this embodiment, the light emitting means 4 is arranged in the light emitting means mounting chamber 11 so as to be slidable back and forth along the optical axis 1b. In particular,
A through groove 46 is provided in the lower side plate 35 so as to extend horizontally, and a screw B is inserted into the through groove 46, and the screw B is provided on the side edge of the light emitting means supporting plate P1 for supporting the light emitting means 4. The holes (not shown) can be tightened and loosened. By tightening and loosening the screw B, the light emitting means support plate P1 and the light emitting means 4 can be moved back and forth along the optical axis 1b to be fixed at a desired position.

The Fresnel lens 5 is a known one, and in this embodiment, its diameter is larger than the maximum inspectable surface diameter to be inspected (140 mm in this embodiment).
The optical axis 1b of the light 1a emitted from the light emitting means 4 passes through the center of the light emitting means 4 and is separated from the light emitting means 4 more than the focal length thereof, and the face plate direction and the optical axis 1
It is erected at the boundary between the mirror mounting chamber 12 and the light emitting means mounting chamber 11 so that it is orthogonal to b.

The half mirror 6 is a known one that reflects almost half of the emitted light and transmits the other half, and the lower end edge thereof is supported by the bottom cover 83 and is behind the Fresnel lens 5. Is disposed above the opening 99. Specifically, the upper surface is inclined forward by 45 degrees so that it is located forward of the lower end, and
Is parallel to the left and right horizontal axes.

The reflection surfaces of the three total reflection mirrors, that is, the first total reflection mirror 7, the second total reflection mirror 8 and the third total reflection mirror 9, become smaller in that order, and the light 1a from the light emitting means 4 is emitted. Among them, the light 1a that is irradiated and reflected on the inspection object 98 arranged under the opening 99 is sequentially reflected,
This is for guiding to the CCD camera 10.

The first total reflection mirror 7 is provided above the half mirror 6. Specifically, the upper end is inclined rearward by 45 degrees so that it is located rearward of the lower end, and the reflecting surface 71 is parallel to the horizontal horizontal axis.

The second total reflection mirror 8 is provided behind the first total reflection mirror 7. Specifically, the upper end is tilted forward by 45 degrees so that the upper end is located forward of the lower end, and the reflecting surface 81 is parallel to the horizontal horizontal axis.

The third total reflection mirror 9 is provided below the second reflection mirror 8. Specifically, the upper end is tilted backward by 45 degrees so that it is located rearward of the lower end, and the reflecting surface 91 is parallel to the horizontal horizontal axis.

The CCD camera 10 is provided with a lens 101, and the center of the lens 101 is arranged on the front-rear horizontal axis passing through the approximate center point of the third total reflection mirror 9, and the direction of the face plate of the lens 101. The horizontal axis is orthogonal. In this embodiment, the CCD camera 10 is
In the image pickup means mounting chamber 13, the upper side plate 33 is supported via the camera support plate P2. This camera support plate P
2 is fixed between the upper side plates 33 so as to be slidable back and forth. Specifically, the screw B is inserted into a through groove 56 provided in the upper side plate 33 so as to extend in the front and rear direction.
By screwing the screw B into a screw hole (not shown) provided on the side edge of the camera support plate P2, the camera support plate P2 and the CCD camera 10 are moved back and forth along the optical axis 1b or fixed. I am able to do it. Further, the CCD camera 10 is provided with a cord 57 capable of outputting a captured image and the like to the outside and a connector (not shown) at the tip thereof so that the image can be viewed on a display or the like. .

The operation of the surface inspection apparatus 1 described above will be described.

First, in use, the mirror surface portion 2 of the inspection object 98 such as a CD is arranged so as to face the opening 99. When the light emitting means 4 is actuated, the light 1a emitted from the light emitting means 4 advances toward the horizontal rear while spreading, and passes through the Fresnel lens 5 to be bent so that the light 1a gradually converges. To be made. The refracted light 1a is reflected by the half mirror 6 and changes its direction so as to travel vertically downward, passes through the opening 99, and is applied to the mirror surface portion 2 of the inspection object 98. Then, the light is reflected by the mirror surface portion 2 and advances vertically upward, passes through the opening 99 and the half mirror 6, and gradually converges toward the first total reflection mirror 7. Next, the direction is changed so that the light is reflected by the first total reflection mirror 7 and proceeds horizontally toward the rear, and thereafter, by the second total reflection mirror 8,
The direction is changed so that it is reflected and proceeds vertically downward. Finally, the light is reflected by the third total reflection mirror 9 and turned toward the front in the horizontal direction to be taken into the CCD camera 10 in a state close to the converged state.

Therefore, in this case, in addition to the effect of the first embodiment, the light 1a after being reflected by the object to be inspected is reflected a plurality of times inside the apparatus main body to increase the optical path length, Since it is installed in the CCD camera 10, it can be suitably applied to those having a relatively large mirror image surface 2 such as a CD and a DVD, and can contribute to downsizing of the device, which is suitable for practical use. You will be able to achieve the size and price you want. <Third Embodiment> Next, a third embodiment of the present invention will be described with reference to FIGS.
2 will be described. Since the third embodiment is different from the second embodiment only in the structure of the light emitting means 4, the description of the structure other than the light emitting means 4 will be omitted in principle. The members corresponding to those in the first and second embodiments are designated by the same reference numerals.

The light emitting means 4 is provided near the focal point of the Fresnel lens 5, and is a point light emitting element 4A which is a point light source or a light source close to the point light source, and a ring arranged so as to surround the point light emitting element 4A. The surface emitting element 4B in the shape of a circle is provided, and the point light emitting element 4A and the surface emitting element 4B are configured to emit light in a switchable manner.

The point light emitting element 4A is the same as that of the first embodiment in terms of its structure and arrangement position, and therefore detailed description thereof will be omitted.

As shown in FIGS. 11 and 12, the surface emitting element 4B includes a disk-shaped transparent body 141, and the transparent body 14.
One of the face plate portions 141a is provided with a disc-shaped holder P1 and a plurality of LEDs 143 provided around the outer periphery of the transparent body 141 so as to emit light toward the center. A through hole 144 penetrating in the thickness direction is provided, and the other face plate portion 141b of the transparent body 141 is used as a light emitting surface for surface emission. The light emitting surface 141b is attached integrally to the point light emitting element 4A in a posture in which the light emitting surface 141b is parallel and opposed to the Fresnel lens 5. Explaining each part in detail, the holder P1 is opaque, and a screw hole P1b for mounting is provided on the end surface P1a on the side opposite to the transparent body.
The transparent body 141 has a plurality of recesses 141c formed on the outer peripheral surface thereof at regular intervals, and the LEDs 143 are embedded in the recesses 141c. Further, the light emitting surface 141b has a ground glass surface shape, and is configured so that uniform surface light emission is performed. Alternatively, the LEDs may be laid on one face plate portion of the transparent body without surrounding, and the light emitting surface may be directly irradiated with the light emitted from these LEDs.

However, the point light emitting element 4A and the surface light emitting element 4B can be switched to emit light. Then, during the above-described mirror surface inspection, the point emission element 4A is turned on, and when inspecting the printed surface or the like,
The surface emitting element 4B is turned on.

By doing so, by lighting and illuminating the surface emitting element 4B, it becomes possible to inspect a surface other than a mirror surface such as a printing surface. In particular, in this device, the diffusion of the illumination light is promoted by passing through the Fresnel lens 5, so that the inspection accuracy thereof is improved. In this case, it is preferable that the illumination light is white and the imaging device 10 is capable of color display.

Since the printing condition can be inspected,
By installing it together with a printing machine that prints on the anti-mirror surface of a CD or the like, it becomes possible to carry out the process from product manufacturing to inspection in an integrated workflow.

Needless to say, the structure of the light emitting means in this embodiment may be applied to the light emitting means in the first embodiment. <Fourth Embodiment> Finally, a fourth embodiment of the present invention will be described with reference to FIGS. The members corresponding to those in the first, second and third embodiments are designated by the same reference numerals.

The surface inspection apparatus 1 is, for example, smaller than those of the first to third embodiments and has a basic structure of the first embodiment.
It is almost the same as that of the embodiment. Specifically, this device is provided with a casing 3 as an apparatus main body, a light emitting means 4, a total reflection mirror 7, a Fresnel lens 5, a half mirror 6, and a CCD camera 10 as an image pickup means. And the first
The main differences from the embodiment are that the CCD camera 10 is detachably attached to the outside of the apparatus main body, and that a refracting lens R is arranged on the optical axis 1b and in the vicinity of the CCD camera 10 to refract the light. The point is that the lens R can be slid along the optical axis 1b.

Explaining each part in detail, the casing 3 has a rectangular top plate 301, a pair of side plates 302 extending downward from the long side portions of the top plate 301, and the top plate 3
01 from the front side to the side plate 302 in the opposite direction, that is, from the outside, between the peripheral edge of the side plate 302 and the second cylinder 305 extending upward from the opposite front side of the top plate 301. And the cover 304 covered as described above. The tubular body 303 has a cylindrical shape with upper and lower surfaces opened,
The lower end portion is embedded so as to penetrate the top plate 301. In addition, approximately half on the front side between the lower edges of the side plates 302 is
It is not covered by the cover 304, and an opening 99 is formed in that portion.

The light emitting means 4 has a columnar light-transmitting body 42 having a light guide surface 43 at the front end and a light-emitting surface 41 at the base end, and the light emitted from the columnar light-transmitting body 42 is the same as in each of the embodiments. Light guide surface 4
A point light source element 4A composed of a plurality of LEDs 44 arranged so as to be concentrated on 3 is built in a stepped cylindrical casing 104, and the light 1a is emitted from the light emitting surface 41. It is configured in. It is to be noted that the plate-like light diffusing plate portion 47 is superposed on the light emitting surface 41 of the columnar light-transmitting body 42 so that the light diffusing action is carried out at that portion as in the above-mentioned respective embodiments. Is.

Further, the light emitting means 4 has a cylindrical second tube that penetrates the top plate 301 in the thickness direction with the light emitting surface 41 facing downward, that is, with the light 1a emitted vertically downward. The body 305 supports the small-diameter portion 141 of the housing 104.

The total reflection mirror 7 has a casing internal space SS.
Is a plane mirror fixed at an angle of 45 degrees diagonally to the front side, and changes the traveling direction of the vertically downward light 1a emitted from the light emitting means 90 by 90 degrees, and travels horizontally toward the front side. To do.

The Fresnel lens 5 has a space S in the casing.
The face plate direction is erected vertically in the approximate center of S, and the optical axis 1b of the light beam 1a reflected by the total reflection mirror 7 passes through the center thereof and is also refracted after passing through the center. , Are arranged at positions that are close to parallel and have a converging direction.

The half mirror 6 is a flat plate-like member which reflects almost half of the emitted light and transmits the other half.
It is fixed on the front plate side of the casing internal space SS, above the opening 99 and in front of the Fresnel lens 5, in a posture parallel to the total reflection mirror 7, that is, at an angle of 45 degrees obliquely.

The CCD camera 10 is detachably attached to the male screw portion 331 provided on the upper end of the cylindrical body 303. The CCD camera 10 reflects on the object 98 to be inspected, passes through the half mirror 6, and is vertically cylindrical. It is attached in such a posture that the light 1a traveling along the body can be introduced. Further, the CCD camera 10 is provided with a cord 57 capable of outputting a captured image and the like to the outside and a connector (not shown) at the tip thereof so that the image can be viewed on a display or the like. .

Further, in this embodiment, a refracting lens R is arranged at an intermediate position of the cylindrical body 303 so that the refracting lens R can be slid up and down along the optical axis 1a. Specifically, the refracting lens R is arranged along the inner circumference of the cylindrical body 303 via the lens support R1 fixed to the outer circumference thereof, and is screwed into the through groove 66 provided so as to extend vertically in the cylindrical body 303. B is inserted and the screw B is screwed into the screw hole N formed in the lens support R1 so that the refractive lens R can be moved up and down and fixed at an arbitrary position.

With such a structure, not only the same operational effect as the first embodiment can be obtained, but also the light emitting means 4 and C
Without moving the CD camera 10 with respect to the casing 3, it is possible to change the field of view and focus only by sliding the refractive lens. That is,
In order to expand the field of view, the distance between the object to be inspected and the device is increased and the refracting lens R is moved upward.
The opposite is true for reduction. By reducing the number of movable parts in this way, operability can be improved.

As a modified example of the fourth embodiment, FIG.
8 and those shown in FIG. In this modification, a concave portion 303a is provided in the cylindrical body 303, the through groove 66 is formed in the concave portion 303a, and an opening / closing lid 303b that covers the opening of the concave portion 303a is provided, without impairing the sliding function of the lens R. It is possible to prevent external light from entering the inside of the device through the through groove 66 and adversely affecting the inspection. Further, in this modified example, the cylindrical body 30
The male screw portion 331 provided at the upper end of the
It is configured so that it can be rotated around its axis and fixed at an arbitrary angle. Specifically, the male screw portion 331 is fixed by a set screw TB. This is because when the CCD camera 10 is screwed into the male screw portion 331 and fixed, the angle of the CCD camera 10 with respect to the apparatus main body is
This is to allow arbitrary setting.

The present invention is not limited to the above embodiments. For example, if the total number of total reflection mirrors in the second and third embodiments is increased to an even number, the image captured by the image pickup means will not be a mirror image, and the workability of surface inspection can be improved. FIG. 20 shows this as a fifth embodiment.
Shown in. In the fifth embodiment, as compared with the third embodiment, another total reflection mirror 9A is added, the light 1a introduced into the CCD camera 10 is directed upward, and the CCD camera 10 is placed vertically. ing. In addition, the point light emitting element 4A also has a vertical posture in which the light emitting surface 41 faces downward, and the light diffusing portion 47 is perpendicular (longitudinal) to the traveling direction of the light 1a that is horizontally and horizontally oriented by the reflection mirror MR. Is arranged so that the light diffusion action is performed. As a result, the depth direction can be made compact.

Further, the light source may be an LED, an optical fiber or the like. Matte processing is not limited to black alumite processing.

Needless to say, the above-described surface inspection apparatus can be used by turning it over so that the position of the opening is on the upper side, and the posture can be changed according to the application. is there.

The specific construction of each of the other parts is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0072]

According to the present invention described in detail above, since the scratched portion and the other portion are clearly separated by the light and dark, linear scratches such as scratches and the like which cannot be found by the conventional surface inspection apparatus. It is possible to reliably detect minute scratches or markings due to dents or the like.

On the other hand, if such a method is simply used and it is attempted to deal with a device having a comparatively large surface to be inspected such as a CD or a DVD, the device becomes large in size and expensive as described above. However, in the lens for collimating the light,
By using a thin Fresnel lens that has a short focal length and is inexpensive, and further introduces the light after hitting the surface to be inspected and reflected multiple times inside to increase the optical path length and introduce it into the imaging means, it can be used in real time. The size and price can be realized.

If an even number of reflection mirrors are provided,
It is possible to prevent the image captured by the image capturing means from being left-right or up-down from the actual object.

In the case where the image pickup means is detachably fixed to a predetermined position of the apparatus main body, a refracting lens is arranged on the optical axis and in the vicinity of the image pickup means, and the refracting lens can be slid along the optical axis. Alternatively, the light emitting means may be provided so as to be movable along the optical axis of the light emitted from the light emitting means, or the image pickup means may be provided so as to be movable along the optical axis of the light guided to the image pickup means. For example, it becomes possible to flexibly cope with the change in the optical path length due to the difference in the installation position of the object to be inspected and easily adjust the imaging position and the visual field.

The light emitting means is arranged so that the light-transmitting means has a columnar light-transmitting surface at one end and a light-emitting surface at the other end, and the emitted light is concentrated on the light-guided surface of the columnar light-transmitting body. A structure comprising a plurality of LEDs or optical fibers, configured to emit the light from the light emitting surface, wherein the light emitting surface of the columnar light-transmitting body is provided with a light diffusing portion that performs a light diffusing action. if there is,
Fresnel lens mounting error, distortion, CD or DVD
Due to a slight tilt or warp of the table on which the object to be inspected is placed, part of the light radiated to the non-scratched part is reflected so that it does not go to the converging point, and as a result, the imaging means It is possible to avoid that the non-scratch portion in the projected image is slightly darkened and the contrast between the scratched portion and the image is not clear. Therefore, it becomes possible to allow the mounting error and distortion of the Fresnel lens, and the inclination and warpage of the table on which the inspection object is placed to some extent.

If the main body of the apparatus is partially or wholly frosted, the surface inspection can be satisfactorily performed.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a surface inspection apparatus according to a first embodiment of the present invention.

FIG. 2 is a side sectional view showing the internal structure of the surface inspection apparatus according to the embodiment.

FIG. 3 is a front view showing a surface inspection apparatus according to the same embodiment.

FIG. 4 is a CD photographed by a CCD camera in the example.
Video.

FIG. 5 is an exploded perspective view showing a surface inspection apparatus according to a second embodiment of the present invention.

FIG. 6 is a side sectional view showing the internal structure of the surface inspection apparatus according to the embodiment.

FIG. 7 is a front view showing the surface inspection apparatus in the embodiment.

FIG. 8 is a bottom view showing the surface inspection apparatus in the example.

FIG. 9 is a side sectional view showing the internal structure of the surface inspection apparatus according to the third embodiment of the present invention.

FIG. 10 is a front view showing the surface inspection apparatus in the embodiment.

FIG. 11 is a plan view showing a surface emitting element according to the embodiment.

FIG. 12 is a vertical cross-sectional view showing a surface emitting element in the example.

FIG. 13 is an overall perspective view showing a surface inspection device according to a fourth embodiment of the present invention.

FIG. 14 is a side view of the surface inspection apparatus in the example.

FIG. 15 is a rear view of the surface inspection apparatus in the example.

16 is a cross-sectional view taken along the line AA in FIG.

17 is a sectional view taken along line BB in FIG.

FIG. 18 is an overall perspective view showing a surface inspection device in a modified example of the same embodiment.

19 is a cross-sectional view taken along the line CC in FIG.

FIG. 20 is a side sectional view showing the internal structure of the surface inspection apparatus in the fifth embodiment of the present invention.

FIG. 21: CD photographed by a conventional surface inspection device
Video.

FIG. 22 is an image of an inspection surface having printed characters taken by a CCD camera by the surface inspection device according to the first embodiment of the present invention.

FIG. 23 is a schematic view showing a conventional surface inspection device.

[Explanation of sign]

1-Surface inspection device 1a ... light 1b ... optical axis 2 ... Inspected surface (mirror surface) 3 ... Casing 4 ... Light emitting means 4A: point-emitting element 41 ... Light emitting surface 42: Columnar translucent body 43 ... Light guide surface 44 ... LED 47 ... Light diffuser 5 ... Fresnel lens 6 ... Half mirror 7 ... Total reflection mirror 8 ... Total reflection mirror 9 ... Total reflection mirror 10 ... Image pickup means (CCD camera) 92 ... scratch R ... Refractive lens

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2G051 AA51 AA71 AB07 BA01 BA20                       BB02 BB09 BB11 BB17 CA04                       CA06 CB01 CB05 DA01                 4M106 AA01 BA04 CA38 DB04 DB07                       DB12 DB13                 5D121 AA02 AA04 HH01

Claims (8)

[Claims] 1. A method for inspecting a scratch generated on a surface to be inspected having a mirror surface and reading an inscribed inscription,
A light emitting means having a point light emitting element which is a point light source or a light source close to the point light source, a Fresnel lens, a half mirror, and an image pickup means are supported on the apparatus main body, and light is emitted from the light emitting means to emit the light. The light is refracted by the Fresnel lens to be a light having a direction of converging close to parallel, and the light refracted by the Fresnel lens is reflected by a half mirror to irradiate almost the entire surface to be inspected, and the surface to be inspected. A surface inspection apparatus characterized in that the light reflected by is guided to an imaging means provided in a portion where the light is converged. 2. The surface inspection apparatus according to claim 1, wherein the light reflected by the surface to be inspected is reflected a plurality of times by a plurality of reflection mirrors provided inside the apparatus main body and is guided to an image pickup means. 3. The surface inspection apparatus according to claim 2, wherein an even number of reflection mirrors are provided. 4. The image pickup means can be detachably fixed to the outside of the apparatus main body, and a refraction lens is arranged on the optical axis and near the image pickup means, and the refraction lens can be slid along the optical axis. The surface inspection apparatus according to claim 1, 2, or 3. 5. The surface inspection apparatus according to claim 1, wherein the light emitting means is provided so as to be movable along the optical axis of the light emitted from the light emitting means. 6. The surface inspection apparatus according to claim 1, wherein the image pickup means is provided so as to be movable along the optical axis of the light guided to the image pickup means. . 7. A columnar light-transmitting element having a light guide surface at one end and a light-emitting surface at the other end, and a light-emitting element for irradiating light is concentrated on the light guide surface of the columnar light-transmitting body. Multiple LEDs arranged
2. The surface according to claim 1, further comprising an optical fiber, configured to emit light from the light emitting surface, wherein the light emitting surface of the columnar light-transmitting body is provided with a light diffusing portion that performs a light diffusing action. Inspection device. 8. The device body according to claim 1, wherein a part or all of the device body is matt processed.
The surface inspection device according to 3, 4, 5, 6 or 7.