JP3523411B2 - Optical member inspection apparatus and inspection method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for inspecting a transparent optical member mainly made of plastic, and more particularly to an apparatus and method using an image processing technique.

[0002]

2. Description of the Related Art Recently, in order to reduce the weight and cost of a photographing lens system and a finder of a camera, an optical member made of plastic is often used.

The plastic optical member has a possibility that dust such as plastic which remains in the mold and carbonized during the injection molding may enter the inside, and the material is softer than the glass optical member. It is easily scratched and it is important to inspect it before assembling it as a product.

Conventionally, inspection of optical members such as lenses and prisms has relied on visual inspection performed by a skilled person while illuminating the optical members with strong light. The purpose of the inspection is to determine whether or not the target optical member has sufficient performance to be used as a product, that is, whether it can be used as a good product or is discarded as a defective product.

When dust is mixed in, factors such as the size of the dust, the depth in the direction of the optical axis, and the distance from the optical axis are factors to be judged. On the other hand, in the case of scratches, factors such as the size of the scratches, which surface has the scratches, and the distance from the optical axis of the dust are factors to be judged.

[0006] When judging whether the product is a good product or a defective product, the judgment criteria are different depending on whether dust is mixed or scratched.
For example, there is a case where dust with the same size is allowed but scratches are not allowed. Therefore, the inspector makes a property determination whether the generated defect is dust or scratches. It is necessary to discriminate the non-defective product from the defective product based on the degree of the defect.

[0007]

However, in the above-mentioned conventional inspection method, much of the quality judgment depends on the subjective judgment of the inspector. Even if there is, the discrimination standard may change due to the difference in physical condition, etc., and it is difficult to maintain the uniformity of the determination.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object thereof is to provide an optical member inspection apparatus capable of judging the quality of an optical member on the basis of an objective standard. An object of the present invention is to provide a device that can be used even when an optical member to be inspected has a function of a wedge prism that deflects a light beam to one side.

[0009]

In order to achieve the above object, an optical member inspection apparatus according to the present invention emits a light beam.
The light beam from the light source to a planar shape of each specimen similar
A peripheral region for diffusing the light flux with a high diffuse transmittance, and a region surrounded by the peripheral region.
The diffused means having a central area for diffusing the light flux with a diffuse transmittance lower than the range makes the light incident on the object to be inspected, and the light is transmitted through the object to be inspected by the imaging means provided at a position to reach. The object is photographed to inspect the object for defects, and the image is transmitted through the optical member and received by the photographing means.
Only the light flux that is transmitted through the central region
As a limitation, the above-mentioned diffusing means is configured to be movable in a direction perpendicular to the optical axis of the photographing means.

By making the diffuse transmittance of the diffusing means have the above distribution, light from the central region and light oblique to the optical axis from the peripheral region are incident on the test object. The image of the object to be inspected is formed mainly by the light from the central region of low brightness, and the obliquely incident light from the peripheral region does not participate in the image formation.

When a defect such as black dust that absorbs light is present on the object to be inspected, the amount of light reaching the photographing means decreases in the portion corresponding to this defect, so that it is better than the surrounding parts area in the photographed image. Appears as a low brightness area. On the other hand, if there is a defect such as a scratch that scatters light on the test object, the low-brightness light from the central region is scattered and attenuated at the portion corresponding to this defect, but the high-brightness light from the peripheral region is present. Are scattered and reach the photographing means, and as a result, the light amount of the defective portion on the image plane increases, and appears in the photographed image as a region having higher brightness than the surrounding component region.

Therefore, it is possible to simultaneously detect defects having different properties such as absorptive defects and scattering defects in one shot as a region having a lower brightness and a higher brightness than the base brightness which is the average brightness of the original image of the component area. .

When it is attempted to detect a defect having different properties in the optical member by the difference in the brightness based on the base brightness as described above, the normal part (the part not including the defect) of the optical member is transmitted through the photographing means. The luminous flux taken in by must be a low-luminance component transmitted through the central region of the diffusing means.

Therefore, in the apparatus of the present invention, even when the lens to be inspected has a wedge-shaped prism function, at least the diffused light from the central region that has passed through the optical member is efficiently diffused into the photographing means. The means can be moved in the direction orthogonal to the optical axis.

When the distance between the photographing means and the diffusing means is sufficiently large, only the luminous flux which is substantially parallel to the optical axis of the photographing means is incident on the photographing means, so that the diffusing means is moved. Then, by setting the traveling direction of the light beam from the central region that has passed through the optical member to be parallel to the optical axis, almost all of the light beam that passes through the normal portion of the optical member and is captured by the image capturing means is transmitted by the diffusing means. It can be limited to the light flux transmitted through the central region. As a result, it is possible to separate the component region by lowering the luminance of the component region from the luminance of the background region in the photographed image, and it is easy to detect any scattering or absorptive defect.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an optical member inspection device according to the present invention will be described below. The apparatus of the embodiment targets a plastic optical member for inspection. First, Fig. 1
The principle of the optical system of the optical member inspection apparatus according to the present invention will be described with reference to FIG.

The optical system of the apparatus comprises a light source 10 and this light source 1.
First and second diffuser plates 2 for diffusing the light flux emitted from 0
Diffusion means 20 composed of 1, 22 and diffusion means 20
And a CCD camera 30 as a photographing means for taking in and photographing the light flux that has passed through the lenses 1 and 5 to be inspected and the light flux that has passed around the lenses 1 and 5 to be inspected. The light source 10 and the diffusing means 20 constitute the lighting unit 120 as an integrated block. The illumination unit 120 is supported so as to be movable in the y direction perpendicular to the optical axis Ax of the CCD camera 30 shown by the arrow y in the figure.

FIG. 1 is an arrangement for measuring a wedge prism for deflecting a light beam in one direction, or a rotationally asymmetric test lens 5 having the function of such a wedge prism.
Shows the arrangement in the case of measuring a lens that is rotationally symmetric about the optical axis or a lens 1 to be inspected that does not have a prism action such as a plane parallel plate that deflects a light beam in one direction.

The test lenses 1 and 5 are arranged on the optical axis of the CCD camera 30. The CCD camera 30 is composed of a taking lens 31 and a CCD sensor 32, and is adjusted such that the vicinity of the center of the lens 5 to be measured in the thickness direction is a focus plane P. That is, the focus plane P and the CCD sensor 32
The image receiving surface is optically conjugate with the imaging lens 31 and the images of the lenses 1 and 5 to be inspected on the focusing surface P are formed in the range indicated by the symbol O on the CCD sensor 32.

The image output of the CCD camera 30 is provided with an image processing device 40 having a judging means for judging the defect of the lens to be inspected.
The information of the lens 1a to be measured, which has been processed and measured in 1, is displayed on the monitor display 50 which is a display unit.

The first and second diffusing plates 21 and 22 are both substantially similar to the planar shape of the lenses 1 and 5 to be tested, and the second
The diffusion plate 22 has a smaller area than the first diffusion plate 21. The size of the second diffusing plate 22 is set so as to substantially match the planar shape of the lenses 1 and 5 to be tested. The centers of the diffuser plates 21 and 22 coincide with each other,
Moreover, it is arranged so as to be perpendicular to the optical axis Ax of the CCD camera 30. In addition, these diffusion plates 21, 2
2 have the same or different diffusive transmittances from each other, and therefore, considering the diffusing means 20 as a whole,
The central region where the first and second diffusion plates 21 and 22 overlap has a low diffuse transmittance, and the peripheral region where they do not overlap has a relatively high diffuse transmittance.

In the optical member inspection apparatus of the embodiment, the illumination unit 120 is taken into the CCD camera 30 by making the shape of the second diffusion plate and the shape of the optical member substantially coincide with each other and transmitting the illumination unit 120 through the lens to be inspected. The luminous flux to be adjusted is adjusted so as to be substantially limited to only the luminous flux in the central region which has passed through the second diffusion plate.

When the distance between the CCD camera 30 and the diffusing means 20 is sufficiently large, only the light flux which is substantially parallel to the optical axis Ax of the camera is incident on the CCD camera 30. Therefore, C is transmitted through the lens to be inspected as described above.
When limiting the light flux taken into the CD camera 30 to the component that has passed through the second diffusion plate, the traveling direction of the light flux that has sequentially passed through the second diffusion plate 22 and the lenses 1 and 5 to be inspected is the optical axis Ax.
Must be set to be parallel to. Here, the traveling direction of the light flux indicates the directionality of the entire light flux, and is considered as the direction of the light ray passing through the center of the lens that does not depend on the power of the lens.

In order to satisfy the above requirements, when the lens does not have a prism action, the optical axis of the camera, the lens to be inspected and the diffusing means are arranged in a straight line as shown in FIG. In the case where the lens has a prism function, the illumination unit is arranged so that the light beam that has passed through the second diffusion plate 22 and is deflected by the prism function of the lens becomes parallel to the optical axis Ax as shown in FIG. The position of 120 may be adjusted.

By the above adjustment, the light flux that passes through the normal portion of the lens to be inspected and is taken into the CCD camera is almost limited to the light flux that has passed through the second diffusion plate 22, and the image of the component area in the photographed image is It is formed by the low-luminance light that has passed through the second diffusion plate 22. On the other hand, the background area around the component area on the CCD sensor 32 is the second diffusion plate 2
The low-brightness light that has passed through 2 and the high-brightness light that has passed through only the first diffusion plate 21 arrive at both, but the sensor is out of focus with respect to the diffusing means 20, so in the background area. , A uniform luminance distribution higher than the average of the component area can be obtained.

Therefore, the component area and the background area can be separated as areas having different brightness, and
It is possible to detect a scattering defect in the test lens as a high-luminance region in the component region and an absorptive defect as a low-luminance region in the component region. If the light flux that has passed through the normal portion of the lens under test without passing through the second diffuser plate enters the CCD camera without the above adjustment, at least a part of the component area has high brightness, Area separation based on brightness becomes impossible, and even if there is a scattering defect in this high brightness component area, it becomes difficult to detect it.

FIG. 3 shows an example of the planar shapes of the lens to be inspected and the diffusion plates 21 and 22. As shown in FIG. 3 (A-1), when the lens to be inspected is the finder lens 1a having a rectangular planar shape, the first and second diffusion plates 21a and 22
The plane shape of a is preferably a rectangle as shown in FIG. 3 (A-2). When the lens to be inspected is a general circular lens 1b as shown in FIG. 3 (B-1), the plane shapes of the diffusion plates 21b and 22b are shown in FIG. 3 (B-2). It is desirable to use a round street.

Since the inspection apparatus of the embodiment is configured to inspect a plastic lens molded by a multi-cavity mold without cutting it off from the runner, the lens to be inspected has a gate as shown in FIG. The runner R is connected via G.

FIG. 4 is an explanatory view showing an example of an optical path between the light source 10 and the CCD sensor 32. FIG. 4A shows a case where the rotationally asymmetric test lens 5 having a prism action is inspected.
(B) is a rotationally symmetric test lens 1 that does not have a prism action.
The optical path when inspecting is shown. In any case, the light flux reaching the image area (component area) O of the lens to be tested on the sensor 32 is substantially limited to only the low-luminance light from the central area that has passed through the second diffusion plate 22. Therefore, the brightness of the component area O is lower than that of the surrounding area.

In other words, in this example, the low-brightness component emitted from the central region and transmitted through the lenses 1 and 5 to be tested is the CCD.
The high-intensity component that reaches the range O of the lens image on the sensor 32, originates from the peripheral region, and passes through the periphery of the lens 1 to be tested reaches the periphery of the range O of the lens image on the CCD sensor 32. Therefore, in the captured image, as shown in FIG. 5, a high-brightness background area B mainly formed by high-brightness components in the peripheral area reaching without passing through the second diffusion plate 22 and 2 The component region S mainly formed by the low-luminance component of the central region that has passed through the two diffusion plates is included.

Here, if there is a defect that absorbs light on the surface or inside of the lenses 1 and 5 to be inspected, for example, black dust contained in the optical member, a part of the transmitted light from the central region forming the lens image. Is absorbed and the light does not reach the CCD sensor 32, so that a defect image DL having a brightness lower than that of the component region is generated in the component region S of intermediate luminance as shown in FIG.

If there is a defect that scatters light on the surface of the lens 1 to be inspected, for example, if white dust or scratches are present on the surface of the optical member, the light scatters due to this defect, and if there is no defect, C
A part of the high-intensity oblique emission component from the peripheral region that does not reach the range O of the lens image on the CD sensor 32 is part of the range O of the lens image.
As shown in FIG. 7, a defect image DH having a higher brightness than that of the component region is generated in the component region S of intermediate luminance.

For example, when a low-brightness image DL due to an absorptive defect and a high-brightness image DH due to a scattering defect are present on a certain scanning line in the X-axis direction, the pixel row output along this scanning line Is as shown in FIG. The image processing device 40 binarizes using two threshold values SH1 and SH2, so that two different characteristics are obtained as shown in FIGS.
Each type of defect can be extracted independently.

As described above, the light quantity distribution of the illumination light is set in two stages by using the two diffuser plates, and the shape of the second diffuser plate 22 is similar to the planar shape of the lens 1 under test. By doing so, in the component area S whose brightness is lower than that of the background area B,
In the case of an absorptive defect, the defect can be recognized as an image DL having a brightness lower than that of the component region S, and in the case of a scattering defect, the defect can be recognized as a high-brightness image DH. Can be detected simultaneously.

On the other hand, for example, when the light amount distribution of the illumination light is uniform, if there is a scattering defect, the light amount is attenuated because the light beam is scattered at that portion, and the CCD sensor 32 has it. Like the absorptive defect, it is detected as a low-luminance region. Therefore, it is impossible to judge the property of the defect from one image data.

When inspecting a lens, it is necessary to determine the properties because the criteria for determining whether the product is a good product or a defective product differs depending on the property, size, and position of the defect. If the property of the defect can be determined by one inspection as in the embodiment, the inspection procedure can be simplified as compared with the case of inspecting the defect to further characterize the property after the defect is detected. When the lens to be inspected is not set, the light quantity distribution on the CCD sensor 32 does not have regularity, and a substantially uniform light quantity distribution is obtained macroscopically.

Next, the movement amount of the illumination unit 120 when the lens to be inspected has a prism action will be described. C
When the optical axis Ax of the CD camera 30 and the central axis Axc of the illumination unit 120 coincide with each other as a reference position, the movement amount Δy of the illumination unit 120 is the same as the test lens 5 and the illumination unit 120. Let h be the distance in the direction of the optical axis and φ be the deviation angle due to the wedge prism action of the lens 5 to be inspected.
It is calculated by the following general formula (1). Δy = h · tan (φ) (1)

Theoretically, if the illumination unit 120 is moved by the movement amount Δy obtained by this equation, the camera side takes an image of the component area of the lens to be inspected by the light transmitted through the second diffusion plate 22. can do. The above general formula
Since (1) depends only on the action of the wedge prism of the optical member to be inspected, it can be applied to the case where the optical member has the power as a lens and the case where the optical member does not have the power.

In FIG. 9, for the sake of explanation, the shape of the optical member is simplified to a wedge prism 6 having an apex angle θ, and the exit end surface of the wedge prism 6 on the CCD camera 30 side is perpendicular to the optical axis Ax. Here is an example of setting. The angle formed between the optical axis Ax and the normal line of the incident end face of the wedge prism 6 on the illumination unit 120 side is θ, and the incident angle θd of the light beam refracted by the incident end face and coinciding with the optical axis Ax is according to Snell's law. It is as follows. n ・ sin θ ＝ sin θd θd ＝ sin ^-1 (n ・ sin θ)

Therefore, when the wedge prism 6 is inspected with the arrangement as shown in FIG. 9, the movement amount Δy of the illumination unit 120 is as shown in the following equation (2). Δy = h ・ tan (sin ^-1 (n ・ sin θ)) (2)

At the time of actual inspection, the lighting unit 120 is moved using the above calculated value as an index, but finally,
The actually photographed image is displayed on the monitor display 50 and adjusted to a position where the defect to be inspected can be best detected.

In the embodiment, the lighting unit 120 is used.
That is, the light source 10 and the first and second diffusing plates 21 and 22 are moved in parallel as a whole. However, in order to achieve the object of the invention, at least the diffusing means 20 is moved in parallel. It is sufficient, and further, it is sufficient to move only the second diffusion plate 22 that defines the central region of the diffused light.

When the illumination unit 120 is moved as a whole as in the embodiment or when the diffusing means 20 is moved, the area of the first diffusing plate 21 is sufficiently large with respect to the photographing range of the CCD camera. It is necessary to have a margin. If the area of the first diffusion plate is insufficient, the movement of the first diffusion plate may cause a part of the shooting range of the camera to deviate from the first diffusion plate, and the background area of the deviated part becomes dark. The background luminance distribution, which should be originally uniform, varies, which hinders image processing.

If the area of the first diffusion plate has a sufficient margin with respect to the photographing range, the luminance distribution of the background does not vary even when the illumination unit 120 moves, and the component area is separated from the photographing range. When performing image processing, it is possible to easily separate a high-luminance portion as a background area.

[0045]

EXAMPLE Next, an example of a lens inspection device having two sets of left and right inspection optical systems based on the above principle will be described. For the sake of explanation, in the figure, an x axis parallel to the optical axis direction and y and z axes orthogonal to each other in the horizontal plane are set.

As shown in FIGS. 10 and 11, the apparatus body unit 100 is provided with first, second and third guide rail members 110, 111 and 112 along the x-axis direction. First and second guide rail members 110, 11
1 includes a CCD camera 30 and a lighting unit 12, respectively.
0 and 0 are attached so as to be independently displaceable in the x-axis direction. In addition, these first and second guide rail members 11
0 and 111 are supported by position adjusting means 113 fixed to the main unit 100 so as to be independently adjustable in the y-axis direction.

Further, the first and second guide rail members 1
Auxiliary lens unit 130 is detachably attached to 10, 11 and marking point unit 140 for marking a lens having a poor property.

An illumination unit 150 and a CCD camera 151, which constitute a reading unit for reading the cavity number stamped on the runner to be measured, are attached to the third guide rail member 112 so as to be slidable in the x-axis direction. ing.

On the base side of the main body unit 100, a lens holding unit 160 for holding the lens to be inspected while being connected to the runner is provided slidably on a rail 161 arranged in the z-axis direction.

The illumination unit 120 is attached to support substrates 110a and 111a fixed to the lower ends of the first and second guide rail members 110 and 111 so as to be movable in the y-axis direction. Slide rails 110b, 11 for movably supporting the illumination unit are provided on the support substrate 110a.
0c is laid in the y-axis direction, and the lighting unit 120
As shown in an enlarged view in FIG. 12, slide pieces 125 and 126 that engage with the slide rails 110b and 110c are formed in the casing 121 of FIG. Similarly, a slide rail is laid on the support substrate 111a of the other guide rail member 111.

The lighting unit 120 includes a casing 121.
An optical fiber 122 for transmitting light from a light source (not shown) is introduced from the lower side, and one plate-shaped diffusing means 20 is attached to the upper opening. The emitting end of the optical fiber 122 is fixed to the casing 121 by a set screw 123, and the insertion stroke can be changed by loosening the set screw. Since the emission angle of the light from the optical fiber is constant, changing the insertion stroke of the optical fiber has the same effect as changing the distance between the light source and the diffusing means 20, and the amount of light emitted from the central region of the diffusion plate is The ratio with the amount of light emitted from the peripheral region can be adjusted.

On the other hand, the diffusing means 20 has a central area having a small diffuse transmittance and a peripheral area having a large diffuse transmittance, and a plurality of diffusing means 20 are prepared so as to be used according to the planar shape of the optical member to be inspected. There is. These diffusion plates are the first diffusion plate 2 having the standard shape as shown in FIG. 13 (A), which is fitted into the upper opening of the illumination unit 120 shown in FIG. 13 (A).
1 is prepared, and a sheet-shaped second diffusing plate 22 that defines the central region is adhered thereon as shown in (B), and light is shielded from the outer periphery of the peripheral region as shown in (C). The light-shielding mask 23 is bonded and configured.

FIG. 14 shows the lens 5 to be inspected set in the lens holding unit 160 in a state of being connected to the runner R.
FIG. 4 is an explanatory diagram showing a positional relationship between the left and right inspection optical systems. The lens 5 to be inspected is held by inserting the tip of the sprue Sp into the lens holding unit 160, and is rotatably supported about a rotation axis Ax3 parallel to the optical axes Ax1 and Ax2 of the left and right inspection optical systems. ing. The distance between the optical axes Ax1 and Ax2 of the left and right inspection optical systems can be adjusted by scanning the position adjusting means 113, and as shown in the figure, each optical axis is substantially aligned with the optical axis of the lens 1 to be inspected. Adjusted to match.

The position of the illumination unit 120 is set so that the above-mentioned condition is satisfied, that is, the traveling direction of the light beam transmitted through the lens 5 to be inspected is parallel to the optical axis direction of each CCD camera. It is set at a position parallel to the center of the diffusing means 20) by a predetermined amount in the y-axis direction.

[0055]

As described above, according to the present invention, it is possible to detect a defect of an object to be inspected by an image processing method based on an image of the object to be inspected. This enables stable evaluation. Further, by using a diffuser plate having different diffuse transmittances in the central region near the optical axis and in the peripheral region, it is possible to simultaneously detect two types of defects contained in the optical member and having different properties in one shooting.

Further, since at least the diffusing means is movable in the direction orthogonal to the optical axis, even when the lens to be inspected has the function of a wedge prism, the diffused light from the central region which has passed through the optical member is taken by the photographing means. Can be efficiently incorporated into.

[Brief description of drawings]

FIG. 1 is an explanatory diagram including an outline of an optical system and a block of a processing system showing an arrangement when inspecting a lens to be inspected having a prism action by an optical member inspection device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of an optical system showing an arrangement when inspecting a lens to be inspected having no prism action by the optical member inspection apparatus of FIG.

FIG. 3 is an explanatory view showing the shape of a test object and the shape of a diffusing means in the apparatus of FIG. 1 in comparison.

FIG. 4 is an explanatory diagram showing an optical path in a state where a lens to be inspected of the optical system of FIG. 1 is set.

5 is an explanatory diagram showing an image taken by the apparatus of FIG. 1 when the lens to be inspected has no defect.

FIG. 6 is an explanatory diagram showing an image when the test lens imaged by the apparatus of FIG. 1 has an absorptive defect.

FIG. 7 is an explanatory diagram showing an image when the test lens imaged by the apparatus of FIG. 1 has a scattering defect.

8 shows an example of a luminance distribution on one scanning line of an image photographed by the apparatus of FIG. 1, where (A) is a signal of an original image, (B) is a signal obtained by binarizing a low luminance component, and (C) ) Is a signal obtained by binarizing the high luminance component.

9 is an explanatory diagram showing an optical path when a wedge prism is inspected by the apparatus of FIG.

FIG. 10 is a front view showing a specific configuration of an apparatus using the optical system of the embodiment.

11 is a side view of the device of FIG.

12 is a sectional view showing an illumination unit of the apparatus of FIG.

13 is a plan view showing the structure of a diffusing unit of the apparatus shown in FIG.

14 is an explanatory diagram showing a positional relationship between a lens to be inspected set in a lens holding unit of the apparatus of FIG. 10 and left and right inspection optical systems in a state of being connected to a runner.

[Explanation of symbols]

1 Test lens (rotationally symmetric, no prism action) 5 Test lens (rotational asymmetry, prism function) 10 light sources 20 diffusion means 21 First Diffusion Plate 22 Second diffuser plate 23 Shading mask 30 CCD camera 31 shooting lens 32 CCD sensor 40 Image processing device 50 monitor display 120 lighting units

Front Page Continuation (72) Inventor Atsushi Kida 2-36-9 Maenocho, Itabashi-ku, Tokyo Asahi Optical Co., Ltd. (56) Reference JP-A-9-15166 (JP, A) JP-A-9- 15159 (JP, A) JP-A 8-334470 (JP, A) JP-A 8-334434 (JP, A) JP-A 8-334433 (JP, A) JP-A 2-206145 (JP, A) JP-A-1-314955 (JP, A) JP-A-63-163137 (JP, A) Actually open 5-20007 (JP, U) Actually open 58-62247 (JP, U) Actually open 58-44849 (JP, U) (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01M 11/00-11/02 G01J 1/00-1/06 G01J 1/42 G01B 11/00-11/30 102 G01N 21/00-21/01 G01N 21/17-21/61 G01N 21/84-21/958

Claims (4)

(57) [Claims] 1. A light source that emits a light beam , a peripheral region that is similar to the planar shape of an object to be examined , and a peripheral region that diffuses the light beam with high diffuse transmittance, and a peripheral region
An area surrounded with a lower diffusion transmittance than the peripheral area
Provided in a position for receiving the spreading means having a central area for diffusing the light beam, the light beam transmitted through the optical member is the test object passes through the diffusing means, imaging means for imaging the optical member And the luminous flux transmitted through the optical member and received by the photographing means is
It is qualitatively limited to only the light flux that has passed through the central region.
Cormorants, a support mechanism for adjustably supporting at least said diffusing means in a direction perpendicular to the optical axis of the imaging means, the light faculty based on an image signal output from the imaging means
An optical member inspection device, comprising: a determination unit that determines a defect of a material . 2. The optical member inspection device according to claim 1, wherein the support mechanism movably supports an illumination unit in which the diffusion means and the light source are integrated. 3. The optical member inspection according to claim 1, wherein the diffusing means is provided as a flat plate-shaped member substantially perpendicular to the optical axis of the photographing means. apparatus. 4. The inspection method using the optical member inspection device according to claim 1, wherein the light flux that has passed through a normal portion of the optical member and is taken into the photographing means is a component that has passed through a central region of the diffusion means. An optical member inspection including: a step of positioning the diffusing means so as to be substantially limited; a step of inputting an image of the optical member; and a step of judging quality of the optical member based on the input image. Method.