JP6829828B2 - Lens appearance inspection device - Google Patents

Description

The present invention relates to a lens appearance inspection device for inspecting the appearance of lenses such as spectacle lenses and camera lenses.

As an image imaging device for a lens, the one described in Patent Document 1 below is known.
In this device, as described in [0054] and FIG. 1, the light L emitted from the light source 31 is converted into parallel light L1 by the collimator lens 36, and the parallel light L1 is converted into parallel light L1 by the half mirror 35 and the corner cube prism 49. It is transmitted back and forth through the lens 1 to be inspected and is focused on the CCD40A.
On the other hand, in the visual inspection of lenses such as spectacle lenses, in order to prevent dazzling and perform an accurate inspection, the transmitted light of the illumination is not visually inspected, but the scattered light scattered in the abnormal appearance is captured. ing. For example, in a spectacle lens, an abnormality in appearance is perceived as scattered light by the wearer, and an inspection using scattered light is similar to a detection by the wearer (lens user), and in this respect, it can be said that the inspection is suitable for the user.

Japanese Patent No. 4906708

In Patent Document 1, the image of the lens is captured by the transmitted light of the parallel light, and the transmitted light travels in parallel while the light flux passing through the mark or the like is emitted, so that a clear image can be obtained.
However, in Patent Document 1, an image is captured by capturing the transmitted light, which may result in an inspection with a gap from the visual inspection, which may not be suitable for the user, and depending on the mode of the abnormal appearance portion, the luminous flux may be generated. It may reach the image pickup device without diverging and may not be able to capture the appearance abnormality well.
Therefore, it is conceivable to image the scattered light without imaging the transmitted light and automatically perform the same inspection as the visual inspection.
However, in imaging with only scattered light, it is difficult to obtain the contrast ratio required for a sufficiently accurate inspection because the amount of scattered light is small, and in particular, various curve values and frequencies such as those of spectacle lenses are used. In all cases, it is difficult to secure a sufficient amount of scattered light, and it is difficult to obtain a required contrast ratio.
Therefore, it is a main object of the present invention to provide a lens appearance inspection apparatus in which a sufficient contrast ratio is secured in an image captured by scattered light and the inspection accuracy using the image is good. ..

In order to achieve the above object, the invention according to claim 1 uses light having a directional angle of 30 ° or less from each lateral direction, which is a plurality of directions intersecting the optical axis of the lens to be inspected. A camera that has a narrow-angle light illuminating means that illuminates with a certain narrow-angle light, an object-side telecentric lens or a double-sided telecentric lens that is directed to the lens to be inspected, and captures an inspection image, and an inner surface as an antireflection surface. The camera captures the inspection image in a state where the lens to be inspected is illuminated by the narrow-angle light by the narrow-angle light from the lateral direction . The box body has holes, and the holes are arranged so as to be located on the opposite side of the camera from the lens to be inspected, and the narrow-angle optical illumination means is an outer surface of the box body. It is characterized by being placed on top .
The invention according to claim 2 further includes, in the above invention, the lens to be inspected, the narrow-angle optical illumination means, and an enclosure that covers the object-side telecentric lens or the bilateral telecentric lens. The inner surface is characterized by being an antireflection surface that prevents reflection of the narrow-angle light.
The invention according to claim 3, Oite to the invention, furthermore, is characterized in that it comprises a distance adjusting means for adjusting the distance between said inspected lens camera.
The invention according to claim 4 is characterized in that, in the above invention, the narrow-angle light illuminating means illuminates the entire periphery of the lens to be inspected or a part thereof.
The invention according to claim 5 is characterized in that, in the above invention, the lateral direction is a direction orthogonal to the optical axis of the lens to be inspected.

According to the present invention, it is possible to provide a lens appearance inspection device in which a sufficient contrast ratio is secured in an image captured by scattered light and the inspection accuracy using the image is good. ..

It is a perspective schematic view of the lens appearance inspection apparatus which concerns on this invention. It is a vertical center cross-sectional schematic diagram of FIG. It is a top view of the narrow-angle light illumination means in FIG. It is a photograph which shows the inspection image in FIG. It is a photograph which shows the binarized image of the inspection image of FIG. It is a photograph corresponding to FIG. 4 when the stage is not a box body. It is a photograph which shows the binarized image of the inspection image of FIG.

Hereinafter, examples of embodiments according to the present invention will be described with reference to the drawings as appropriate. The form of the present invention is not limited to the following.

≪Composition, etc.≫
FIG. 1 is a schematic perspective view of the lens appearance inspection device 1 according to the embodiment, and FIG. 2 is a schematic view of a vertical center cross section of the lens appearance inspection device 1.
The lens visual inspection device 1 has an enclosure 2 and a horizontal top plate 3, and is opened at a box-shaped stage 4 (box body) arranged at the lower inside of the enclosure 2 and a central portion of the top plate 3. A lens holding mechanism 6 arranged around the hole 5, a narrow-angle optical illumination means 7 arranged on the top plate 3 of the stage 4, a camera 8 installed in the upper part inside the enclosure 2, and a notification means. 9 and a control means 10 for controlling these are provided, and the appearance of the spectacle lens L is inspected. The lens appearance inspection device 1 is suitable for inspecting a spectacle lens L including many lenses having a deep curve (small radius of curvature), but a lens other than the spectacle lens L (deep curve or thick wall). It may be used for the inspection of. Further, at least one of the enclosure 2, the lens holding mechanism 6, and the notification means 9 may be omitted. Further, the lens appearance inspection device may be combined with various inspection devices for performing other inspections related to the lens. In addition, the lens appearance inspection device may be configured by combining a plurality of the following lens appearance inspection devices 1.

The enclosure 2 has a box shape that can be closed and is made of a light-shielding material. The inner surface of the enclosure 2 is anti-reflection processed to prevent light reflection by reducing the reflectance of light, and the inner surface of the enclosure 2 is an anti-reflection surface that prevents light reflection. Here, it is formed so as to exhibit black color (blackening treatment). By attaching the antireflection film, the inner surface of the enclosure 2 with the antireflection film may be formed, and the antireflection surface of the inner surface of the enclosure 2 may be formed.

The stage 4 is supported by a lift 20 as a distance adjusting means so that the top plate 3 can move up and down while being kept in a horizontal posture. The stage 4 (box body) need only have a shape that surrounds the inner surface located below the spectacle lens L so that light does not hit the inner surface as much as possible, and does not need to be completely closed, and windows and doors. There may be an opening such as. Alternatively, the lift 20 may be omitted. Further, a part of the stage 4 may be supported so as to be vertically movable. Further, the stage 4 or a part thereof may be movable to the left or right by a lift 20 or other means.
The outer surface of the stage 4 is black, and the inner surface of the stage 4 is blackened by attaching a black screen.

The lens holding mechanism 6 is a mechanism for holding the spectacle lens L as the lens to be inspected, and here, a pair (two) of hooks 21 and 21 having an L-shaped cross section. One planar portion of each hook 21 is fixed to the inside of the hole 5 (lower surface of the top plate 3) formed in the central portion of the top plate 3, and the other planar portion is in an upright posture. The peripheral edge of the spectacle lens L is supported on the upper portion thereof. The upright portion of each hook 21 has translucency, but may not have translucency as long as it does not interfere with the illumination light. The hooks 21 and 21 are arranged so as to face each other, and their distances are adjusted according to the outer diameter of the spectacle lens L.
The number of hooks 21 may be one or three or more. The hook 21 may be fixed to a position other than the inside of the hole 5. Further, the lens holding mechanism 6 may be a cylindrical member with a flange, and in this case, the inner diameter adjusting means (shape) for matching the size of the inner diameter (inner shape) with the outer diameter (outer shape) of the spectacle lens L. Adjustment means) may be provided. Further, the material of the lens holding mechanism 6 may be resin, ceramics, glass, metal, rubber, or a combination thereof.

The narrow-angle optical illumination means 7 also shown in FIG. 3 includes a housing 23 which is hollow and has a wide cylindrical shape and has a central hole portion 22, and a plurality of narrow-angle optical LEDs 24, 24, and so on arranged in the housing 23. , Narrow-angle light LEDs 24, 24 ... are provided with illumination lenses 26, 26 ...
The outer surface of the housing 23 is black, like the inner surface of the enclosure 2.
Each narrow-angle light LED 24 emits white substantially narrow-angle light. The narrow-angle light is light having a directivity angle of 30 ° or less, and includes parallel light having a directivity angle of 0 °. Approximately narrow-angle light is almost narrow-angle light, but there is still room for fine adjustment to bring it closer to perfect narrow-angle light. For example, it diverges at a directivity angle slightly exceeding 30 ° (). Light that spreads in the distance) and light that diverges due to changes in the directional angle depending on conditions such as voltage. Each narrow-angle light LED 24 may emit substantially narrow-angle light of a color other than white, may emit substantially narrow-angle light other than visible light including ultraviolet rays and infrared rays, or a combination of these. Narrow angle light may be emitted. Further, the narrow-angle light LED 24 may be a parallel light LED that emits parallel light or substantially parallel light. Approximately parallel light is light that is almost parallel light, but leaves room for fine adjustment to approach perfect parallel light, and is slightly focused (although the focusing point is distant) or light that is present. Light that diverges slightly (spreading is observed in the distance) and light whose focusing and divergence change slightly depending on conditions such as voltage.
Each narrow-angle light LED 24 is installed so that the light emitting direction is toward the inside (center) of the central hole 22 of the housing 23.
The narrow-angle optical LEDs 24, 24 ... Are arranged so as to be arranged in the circumferential direction of the housing 23, and here, a total of 16 narrow-angle optical LEDs are arranged at equal intervals in the circumferential direction.
Each illumination lens 26 is arranged inside the corresponding narrow-angle light LED 24, and finely adjusts the optical path of the substantially narrow-angle light emitted from the narrow-angle light LED 24 to obtain narrow-angle light. .. The illumination lens 26 may have substantially narrow-angle light, narrow-angle light, or substantially parallel light as parallel light. Further, the illumination lens 26 may be integrated with the narrow-angle light LED 24, may be common to a plurality of narrow-angle light LEDs 24, 24, ..., Or may be omitted. Further, the means for emitting narrow-angle light is not limited to the combination of the narrow-angle light LED 24 and the illumination lens 26, and may be a laser exciter or the like.

Then, the spectacle lens L is set in the central hole 22 (inspection position) of the housing 23 via the lens holding mechanism 6. The optical axis of the spectacle lens L faces in the vertical direction, and is arranged so that the convex surface is on the bottom when the spectacle lens L is a convex lens, and the concave surface is on the top when the spectacle lens L is a concave lens. Be placed. Since the narrow-angle light illuminating means 7 has narrow-angle light LEDs 24, 24 ... And illumination lenses 26, 26 ... Arranged over the entire circumferential direction of the housing 23, it illuminates the entire periphery of the spectacle lens L. The orientation of the spectacle lens L may be opposite to that described above, but the orientation described above facilitates more appropriate imaging of the scattered light of each lens.
The substantially narrow-angle light emitted from each narrow-angle light LED 24 is parallel to the direction of the narrow-angle light LED 24, becomes narrow-angle light by the corresponding illumination lens 26, and becomes large toward the spectacle lens L. It goes almost straight without spreading or suddenly focusing. The direction of the narrow-angle light emitted from each illuminating lens 26 is a direction intersecting the optical axis of the spectacle lens L, and more specifically, a horizontal direction orthogonal to the optical axis. The light emitting portion of each narrow-angle light LED 24 has a predetermined size (for example, a disk having a diameter of 2 mm (millimeter)), and in the traveling direction related to the narrow-angle light from each narrow-angle light LED 24 or the illumination lens 26. The size of the vertical cross section expands by the direction angle from the size of the light emitting part.
Even when the narrow-angle light reaches the lens holding mechanism 6, at least the reaching portion (the standing portion of each hook 21) has translucency, so that the narrow-angle light passes through the lens holding mechanism 6.
The housing 23 may have another shape such as a wide thick arc shape, and the narrow angle optical LEDs 24, 24 ... And the illumination lenses 26, 26 ... Are arranged over the arc shape. It may be arranged so as not to surround the spectacle lens L. Further, the traveling direction of the substantially narrow-angle light related to the narrow-angle light LEDs 24, 24 ... And the optical axis direction of the illumination lenses 26, 26 ... Are not the directions orthogonal to the optical axis of the spectacle lens L, but the optical axis thereof. It may be oriented at an angle other than 90 °.

The camera 8 includes a camera body 34 having an image sensor 30 and a storage means 32, and a camera lens 36 attached to the lower part of the camera body 34, and is captured from the camera lens 36 based on a command from the control means 10. The image C for inspection is acquired by capturing the image C with the image pickup device 30, stored in the storage means 32, and transmitted to the control means 10. The image sensor 30 is an area sensor here. Note that the camera 8 does not include the storage means 32, and the inspection image C may be immediately transmitted to the control means 10. Further, the storage means 32 may be volatile or non-volatile, and may be a memory, a hard disk, or a combination thereof.
The image sensor 30 and the camera lens 36 are installed so as to face the narrow-angle light illumination means 7 and the spectacle lens L.

The image pickup device 30 is considered to have a relatively high resolution in consideration of the fact that the image pickup is performed only by narrow-angle light. Further, the image pickup device 30 is considered to have a relatively high sensitivity in consideration of the fact that the image pickup is performed only by narrow-angle light.
Further, the camera lens 36 is an object-side telecentric lens in which the main ray on the object-side is parallel to the optical axis of the lens. The camera lens 36 may be a bilateral telecentric lens in which the main ray is parallel to the optical axis of the lens on both the object side and the image side.
Since the camera lens 36 is an object-side telecentric lens, even in a spectacle lens L having a relatively deep depth of field and a deep curve or a large thickness, the depth of field is the entire spectacle lens L. It is like being in focus at.
The actual field of view of the camera lens 36 is relatively wide, preferably 85 mm or more, in consideration of the fact that the image is taken only by narrow-angle light and that the entire spectacle lens L is captured.

The notification means 9 notifies at least the inspection result, and is, for example, a sound generating means, a display means, or a combination thereof. The sound generating means is, for example, a speaker or a buzzer, and the display means is, for example, a lamp, a 7-segment LED, a flat display, or a combination thereof. The display means may be a combination with an input means such as a touch panel. Further, an independent input means (for example, a keyboard, a pointing device, or a combination thereof) may be provided.

The control means 10 is, for example, a microcomputer arranged outside the enclosure 2 or attached to the enclosure 2, and is electrically connected to the lift 20, the narrow-angle light illumination means 7, the camera 8 or the notification means 9, respectively. Each of these is controlled. The control means 10 may be incorporated in at least one of the lift 20, the narrow-angle light illumination means 7, the camera 8 and the notification means 9, or may be dispersed in a plurality of pieces so as to be cooperatively controllable.
Further, the control means 10 is electrically connected to a transport means (not shown) for placing the spectacle lens L at the inspection position or taking it out from the inspection position, and the control means 10 can control the transport means. .. The transport means is, for example, a robot hand, a conveyor, a lift of the spectacle lens L, or a combination thereof. In the case of a conveyor, the narrow-angle light illuminating means 7 can be retracted (for example, raised) or returned (lowered), and the control means 10 retracts the narrow-angle light illuminating means 7 and inspects the spectacle lens L by the conveyor. After that, the narrow-angle optical illumination means 7 may be restored. In the case of a lift of the spectacle lens L, after the spectacle lens L is placed at the retracted (lowered) position of the spectacle lens L mounting portion, the mounted portion returns (rises) to the inspection position, and after the inspection, at the retracted position. The spectacle lens L may be taken out. The transport means may transport the spectacle lens L and the lens holding mechanism 6. Further, the lens appearance inspection device 1 may be combined with a lens cleaning device. In this case, the transporting means transports the spectacle lens L to the lens cleaning device, and after the spectacle lens L is cleaned, the spectacle lens L is taken out and the lens is taken out. It may be transported to the visual inspection device 1.

Further, the control means 10 includes a storage means 40 similar to the storage means 32 of the camera, a communication means 42, and a CPU 44 that controls them.
The lens appearance inspection program 50 and the lens database 52 are stored in the storage means 40.
The lens database 52 associates a lens characteristic value, which is a characteristic value related to the spectacle lens L, with an imaging set value, which is a set value related to imaging by the camera 8. Here, the lens characteristic value is a value indicating the diameter of the spectacle lens L, the curve value (power), the lens design information (diameter of the spectacle lens L, floor height, center thickness, edge thickness, etc.), and the type of coating. , Any part of the value may be omitted, or other values may be added. Here, the floor height is the height from the flat surface to the uppermost portion of the convex surface (the surface opposite to the concave surface) when the convex surface of the spectacle lens L is placed on a flat surface with the convex surface up or the concave surface down, and the center thickness is It is the thickness at the center of the spectacle lens L, and the edge thickness is the thickness at the edge (edge) of the spectacle lens L. Further, various lens characteristic values may be directly input or calculated from other lens characteristic values. On the other hand, the imaging set values are the imaging distance, the exposure time, and the gain, which are the distances between the spectacle lens L and the camera lens 36, but some arbitrary values may be omitted, and other values may be omitted. A value may be added.
The communication means 42 is a means capable of inputting and outputting various types of information, and is, for example, a hub, various terminals, a communication controller, or a combination thereof.
When the lens holding mechanism 6 whose inner shape can be adjusted is connected to the control means 10, the control means 10 controls the inner shape of the lens holding mechanism 6 according to the lens characteristic value (diameter of the spectacle lens L). You may do so.

≪Operation etc.≫
An operation example of the lens appearance inspection device 1 in this manner will be described below.
The lens appearance inspection device 1 is operated by the CPU 44 (control means 10) that executes the lens appearance inspection program 50, for example, as follows.
Under the control of the control means 10, the transport means carries the spectacle lens L to be inspected to the inspection position in the narrow-angle optical illumination means 7.
The lens characteristic value of the spectacle lens L to be carried in is input to the control means 10 via the communication means 42. The lens characteristic value may be input from another computer (not shown), or may be input by an input means (for example, a keyboard, a pointing device, a touch panel, or a combination thereof) not shown.
The enclosure 2 is provided with a door (not shown), which is opened when the spectacle lens L is carried in so that it can pass through the spectacle lens L, and the door is closed by the time of imaging after the carry-in is completed. Blockage by the enclosure 2 is ensured.

The CPU 44 of the control means 10 refers to the lens database 52, acquires an imaging setting value corresponding to the received lens characteristic value, and causes the camera 8 or the lift 20 to perform imaging matching the imaging setting value. A command is sent to the communication means 42. Here, the control means 10 operates the lift 20 to raise or lower the stage 4 through a command to the lift 20 so as to match the imaging distance acquired by the lens database 52, and the glasses on the top plate 3 By raising or lowering the lens L, the position of the spectacle lens L with respect to the camera lens 36 is adjusted, and the imaging distance is adjusted. The stage 4 may be movable in at least one direction, front-back, left-right (horizontal direction). Further, the camera 8 may be moved up and down or horizontally, and both the camera 8 and the stage 4 may be moved up and down or horizontally.
Further, the control means 10 transmits a light emission command for emitting narrow-angle light with a predetermined intensity to the narrow-angle light illumination means 7, and in response to this, each narrow-angle light of the narrow-angle light illumination means 7. The LED 24 lights up. It should be noted that the control means 10 may control the narrow-angle light illumination means 7 so as to illuminate with the illumination intensity so that the illumination set value includes the illumination intensity.

In this way, the spectacle lens L is illuminated by the narrow-angle light emitted from the narrow-angle light illuminating means 7.
Narrow-angle light passes through the inside of the translucent spectacle lens L in a state of intersecting (orthogonally) with the optical axis of the spectacle lens L, and ideally travels horizontally as it is and exits the spectacle lens L. .. Since the narrow-angle light traveling horizontally in this way has a narrow directivity angle and is diffused by that amount, it is difficult to reach the camera 8 arranged above the spectacle lens L, and the surface of the spectacle lens L (with air). Due to reflection, refraction, etc. at the interface), a small part goes toward the camera 8. Such reflection or refraction tends in various directions as the lens has a deeper curve (spectacle lens L). Further, when the narrow-angle light is parallel light, the parallel light does not focus or diffuse when traveling horizontally, and therefore does not ideally go in the direction of the camera 8 arranged above the spectacle lens L. However, in reality, a small part of the spectacle lens L is directed toward the camera 8 due to reflection or refraction on the surface of the spectacle lens L described above.
On the other hand, when foreign matter is attached or mixed in the spectacle lens L, the narrow-angle light that has reached the foreign matter is scattered, and a part of the scattered light (reflected light by the foreign matter) is directed to the camera 8. The intensity of such scattered light is generally greater than the intensity of light due to reflection or refraction described above. The foreign matter is, for example, dust or uneven coloring generated on the surface or inside of the spectacle lens L, bubbles, fixed substances, fragments, unevenness of the film formed on the surface of the spectacle lens L, or a combination thereof.
Further, when the spectacle lens L has scratches / chips or poorly formed parts, the narrow-angle light reaching the scratches / chips or poorly formed parts is also scattered in the same manner as in the case of foreign matter, and a part of the light is scattered on the camera 8. Head. Hereinafter, the foreign matter, the chipped portion, and the poorly formed portion are collectively referred to as a foreign matter or the like.
In addition, even if the narrow-angle light emitted from the narrow-angle light illuminating means 7 reaches the inner surface of the enclosure 2, the inner surface is an antireflection surface, so that the reflection on the inner surface is prevented. The situation where the reflected light from the inner surface is directed to the camera 8 is prevented.

The control means 10 issues an image pickup command to the camera 8, and in response to this, the camera 8 releases the shutter, captures the light captured by the camera lens 36 with the image sensor 30, and sets the pixel information of the still image. Is converted to, and after appropriate image processing, it is stored in the storage means 32 as an inspection image C. Here, one inspection image C is acquired for one spectacle lens L, but a plurality of images may be acquired. Further, the camera 8 may capture a moving image and acquire a moving image for inspection.
Since the inspection image C is acquired by the camera lens 36, which is a telecentric lens on the object side, even a spectacle lens L having a deep curve or a spectacle lens L having a large thickness is in focus in all parts. Therefore, scattered light is generated in the out-of-focus portion due to foreign matter, chipping, etc., and a clear image cannot be obtained, which prevents a situation in which the inspection by the inspection image C is hindered. In addition, the non-telecentric lens distorts the scattered light generated by foreign matter and the like by the amount of the parallax, making the actual size and state of the foreign matter unclear, or when there are a plurality of foreign matter and the like. There is a possibility that some foreign matter may be hidden in the camera lens 36, but the camera lens 36 does not have such a possibility, and all foreign matter and the like can be captured in the actual size and state. Strictly speaking, it is difficult to completely prevent the size change, but the size change is remarkably suppressed as compared with the case of imaging with a non-telecentric lens, and the center and outer periphery of the spectacle lens L are suppressed. When there is a height difference in the spectacle lens L as described above, the deformation of the shape in the imaging portion of the spectacle lens L is suppressed.
The lens database 52 stores the imaging distance according to the diameter and curve value of the spectacle lens L, and in the inspection image C, the entire spectacle lens L is in focus (the entire spectacle lens L is captured). An imaging distance (within the depth of field) is obtained in advance, and is stored in association with the diameter and curve value of the spectacle lens L. As described above, the control means 10 controls the lift 20 and moves the spectacle lens L via the stage 4 and the lens holding mechanism 6 so as to have an imaging distance thereof. Since the camera lens 36 has a telecentric effect at least on the object side, the actual field of view is constant regardless of the imaging distance.
For example, when the actual field of view is 80 mm in length and 80 mm in width, the depth of field is 9 mm, and the center of the depth of field is at a position 150 mm from the tip of the camera lens 36, the floor height is a plus intensity number of 5 mm. With respect to the spectacle lens L (convex lens) of the above, the control means 10 operates the lift 20 so that the position of the center of the floor height (2.5 mm) matches the center position of the depth of field. On the other hand, in the same case, for the spectacle lens L (concave lens) having a negative intensity number with a floor height of 6 mm, the control means 10 so that the position of the floor height center (3 mm) matches the center position of the depth of field. The lift 20 is operated. Here, consider the case where the lift 20 is not provided (the imaging distance is not adjusted). Since the convex lens is located below the support point of the lens holding mechanism 6 and the concave lens is located above the support point of the lens holding mechanism 6, the total vertical width occupied by both lenses (in the floor height direction). The total value of the widths of the lenses is 5 mm below the support point (convex lens) and 6 mm above the support point (concave lens), which is 11 mm. This vertical width of 11 mm is larger than the depth of field of 9 mm, and therefore, if the imaging distance is not adjusted, at least one of the convex lens and the concave lens will be partially out of focus. On the other hand, in the lens appearance inspection device 1, since the imaging distance is adjusted by the lift 20, both the convex lens and the concave lens can be positioned within the depth of field and can be focused over the entire area.
Further, the spectacle lens L is held by the lens holding mechanism 6 that holds the peripheral edge thereof so as to overlap (overlap) the hole 5 of the top plate 3 in the top view, and the camera 8 (camera lens 36) is held in the hole 5. The inside of the hole 5 (the inside of the box-shaped stage 4) is blackened. Therefore, the camera lens 36, the spectacle lens L, and the hole 5 are arranged in the vertical direction, and the hole 5 is located on the opposite side of the spectacle lens L with the spectacle lens L in between. Such an arrangement and the black on the inner surface of the stage 4 By the conversion process, the portion of the inspection image C where scattered light does not occur can be made blacker, and the contrast ratio with respect to the scattered light due to foreign matter or the like is improved. Further, the reflection of the scattered light traveling toward the stage 4 side is prevented inside the stage 4, the reflection of the scattered light not due to foreign matter or the like is suppressed, and the decrease in the contrast ratio in the inspection image C is prevented. Further, since the stage 4 has a box shape and partially or completely covers the lower part of the spectacle lens L (the part on the side beyond the spectacle lens L when viewed from the camera lens 36), the reflected light on the inner surface of the enclosure 2 and the like are covered. Is directed downward from the spectacle lens L, but can be blocked by the stage 4, the reflection of scattered light not due to foreign matter or the like is suppressed, and a decrease in the contrast ratio in the inspection image C is prevented.
The camera 8 transmits the inspection image C thus acquired to the control means 10, and the control means 10 stores the inspection image C received by the communication means 42 in the storage means 40.

The control means 10 determines whether or not an abnormality has occurred in the stored inspection image C. Here, it is determined whether or not the pixels having the brightness of a predetermined value (for example, 128 out of 256 steps) or more in the inspection image C are present in the predetermined range (for example, the range of 3 pixels × 3 pixels) or more. At the time of acquiring the inspection image C, the portion outside the spectacle lens L may be arranged outside the photographing range. Further, the above determination may be made based on a plurality of inspection images C, C ... In addition, the above-mentioned determination may be made depending on whether or not the brightness is equal to or higher than the second predetermined value (the same value as or different from the above-mentioned predetermined value) even within the predetermined range, and the brightness is the third. It may depend on whether or not a predetermined number or more of pixels which are equal to or more than the predetermined value (the same value as or different from the above-mentioned predetermined value or the second predetermined value) or more are adjacent to each other, or a combination thereof may be used.
The control means 10 outputs a determination result that an abnormality has occurred in the inspection image C when pixels having a brightness of a predetermined value or more are present over a predetermined range or more.
Then, when the control means 10 obtains a determination result that an abnormality has occurred in the inspection image C, it indicates that an abnormality is found in the appearance of the spectacle lens L related to the inspection target (inspection result is abnormal). ), The notification means 9 notifies. The notification of the occurrence of an abnormality may be the generation of a buzzer sound, the lighting of a lamp, the pronunciation or display of a message, or a combination thereof. Further, when the notification means 9 includes the display means, the inspection image C may be displayed on the display means. In addition, the notification means 9 may notify that no abnormality is found (inspection result is normal) in a mode different from the mode of notification of abnormality occurrence.

When the determination process or the abnormality occurrence notification process for the inspection image C is completed, the control means 10 commands the narrow-angle light illumination means 7 to turn off the light, and also carries out the spectacle lens L by the transport means to carry out the next inspection target. If the spectacle lens L is present, the above process is repeated. The lighting of the narrow-angle light illumination means 7 may be continued.

≪Effects, etc.≫
The lens appearance inspection device 1 described above emits narrow-angle light having a directivity angle of 30 ° or less from the lateral direction, which is the direction in which the spectacle lens L, which is the lens to be inspected, intersects the optical axis of the spectacle lens L. It has a narrow-angle light illuminating means 7 illuminated by a narrow-angle light LED 24, 24 ... and an illumination lens 26, 26 ..., and a camera lens 36 which is an object-side telecentric lens directed to the spectacle lens L for inspection. A camera 8 for capturing the image C for inspection is provided, and the camera 8 captures the image C for inspection in a state where the spectacle lens L is illuminated by the narrow-angle light illuminating means 7 from the lateral direction. ..
Therefore, in the generation of the inspection image C, the camera 8 hardly captures the narrow-angle light transmitted in the lateral direction through the normal portion without foreign matter, while the camera 8 reaches the abnormal portion with foreign matter and is reflected. The angular light is clearly captured, and the contrast ratio in the inspection image C becomes extremely good, which makes it easier to find foreign matter and the like. Further, since the camera 8 generates the inspection image C through the camera lens 36 which is the object-side telecentric lens, even if the spectacle lens L has a large wall thickness or curve value, the wall thickness direction (optical axis direction of the spectacle lens L). ), A clear inspection image C can be obtained over the entire surface, and since it is not necessary to acquire a plurality of images having different focus positions, the processing amount and the inspection time are reduced, and foreign matter or the like on any part of the spectacle lens L is reduced. Can be detected at an appropriate position or size in the inspection image C even if a foreign object or the like occurs, and even if a plurality of foreign substances or the like occur, they can be captured at an appropriate position or size in the inspection image C. Therefore, accurate inspection can be ensured by the inspection image C.
In particular, when the inspection by the lens appearance inspection device 1 is compared with the inspection using transmitted light as in Patent Document 1 described above, in the inspection of transmitted light, the portion corresponding to foreign matter and the like is dark and the other portions are bright. Since the image is used, the inspection is not suitable for the situation where the user feels a foreign substance, and the light beam reflected by the foreign substance does not diverge well, so that it is not captured by the camera and may affect the accuracy of the inspection. However, in the inspection of the lens appearance inspection device 1, the inspection image C in which the part corresponding to the foreign matter is bright and the other part is dark can be used, and the inspection can be performed according to the user's situation. A good contrast ratio can be secured to ensure excellent inspection accuracy.
On the other hand, as compared with the direct visual inspection using reflected light, the diffused light such as a foreign substance is enlarged or reduced by the action of the spectacle lens L, which causes an erroneous judgment, and such enlargement or reduction. The degree of the difference depends on the power of the spectacle lens L, and the difference is particularly remarkable in the lens to be inspected such as the spectacle lens L having various powers, and such a difference is also a cause of erroneous judgment. However, in the inspection of the lens appearance inspection device 1, at least in the inspection image C imaged by the lens whose object side is telecentric, the diffused light such as foreign matter has the same magnitude regardless of any part of the spectacle lens L. An image is taken, and any spectacle lens L of any power is imaged with the same size, so that erroneous determination is avoided and a more accurate inspection can be performed.

In addition, a stage 4 having an inner surface as an antireflection surface is provided, and the stage 4 has a hole 5, and the hole 5 is opposite to the camera lens 36 (camera 8) with the spectacle lens L interposed therebetween. Is arranged so that is located. Therefore, the inner surface on the other side of the spectacle lens L as viewed from the camera lens 36 can be separated from the spectacle lens L, and the reflected light and the repeatedly reflected light are prevented from entering the stage 4 and slightly. Even if it enters, the reflection is suppressed by the antireflection surface, and as a result, the reflected light and the scattered light are not illuminated on the above-mentioned inner surface where the distance from the spectacle lens L is secured, so that the decrease in the contrast ratio is suppressed. The contrast ratio of the inspection image C can be further improved, and the inspection image C capable of performing a more accurate inspection can be obtained.
FIG. 4 is a photograph showing an inspection image C when the stage 4 is a box body as in the lens appearance inspection device 1, and FIG. 5 is a binarization of the inspection image C of FIG. 4 (brightness threshold). Value: 16/256 from the dark side) The photograph shows an image, and FIG. 6 shows an inspection image C when the stage is not a box (there is no light intrusion prevention means for the surface below the spectacle lens L). FIG. 7 is a photograph showing a binarized image of the inspection image C of FIG. 6 in the same manner.
Although the contrast ratio is also good in the photograph of FIG. 6, each of the upper right, lower right, upper left, and lower left portions immediately inside the narrow-angle light illumination means 7 is a portion P having higher brightness than the surroundings. The generation of such a portion P is formed by dividing the narrow-angle optical illumination means 7 into four parts for each arc having a central angle of 90 °, and the joint surface thereof and parts (screws, etc.) used for the joint. Due to the appearance of reflected light from. The occurrence of these partial Ps is prominent in the photograph of FIG. 7 related to binarization, and depending on the setting of the threshold value or the like, when analyzing a high-luminance portion, that is, an existing portion such as a foreign substance in the binarized image, The reflected light from the joint surface or parts may be mistaken for an existing part such as a foreign substance.
On the other hand, in the photograph of FIG. 4, the contrast ratio is further improved as compared with the photograph of FIG. 6, and the brightness of the reflected light due to the structure (junction) of the narrow-angle light illumination means 7 is suppressed. .. Such suppression of brightness can be clearly seen from the fact that in the photograph of FIG. 5 relating to binarization, the partial P does not appear even after binarization as in the photograph of FIG. 7.
From these photographs, it can be seen that the installation of the box body (stage 4) has the effect of preventing reflection of reflected light (including the one from the narrow-angle light illumination means 7) and the effect of improving the contrast ratio.

Further, the spectacle lens L, the narrow-angle light illumination means 7, and the enclosure 2 covering the camera 8 having the camera lens 36 are provided, and the inner surface of the enclosure 2 is the narrow-angle light emitted from the narrow-angle light illumination means 7. It is painted black so that it is an anti-reflection surface that prevents reflection. Therefore, it is possible to prevent the ingress of external light (natural light, illumination light, etc.) from the outside into the enclosure 2 to prevent the appearance of the external light in the inspection image C, and to prevent the narrow-angle light on the inner surface of the enclosure 2. Further reflection (repetition of reflection) of reflected light and reflected light can be suppressed, the appearance of the reflected light in the inspection image C can be prevented, and an excellent contrast ratio can be realized in the inspection image C. It is possible to acquire an inspection image C capable of performing a highly accurate inspection.
Further, since the lens appearance inspection device 1 includes a lift 20 for adjusting the imaging distance, which is the distance between the spectacle lens L and the camera 8, the spectacle lens L having different characteristic values is continuously inspected. Even in the case, it is possible to secure an imaging distance that matches the characteristic value, and a small number of clear inspection images C (here, one image) are provided for the entire spectacle lens L related to any characteristic value. ), It is possible to realize an accurate inspection with a small amount of processing amount and inspection time.

Furthermore, since the narrow-angle light illuminating means 7 illuminates the entire periphery of the spectacle lens L or a part thereof, it is possible to evenly apply the narrow-angle light in the lateral direction to the spectacle lens L, which is more reliable. It is possible to obtain an inspection image C for more accurate inspection by causing reflection of foreign matter or the like.
In addition, since the direction in which the narrow-angle light illuminating means 7 irradiates the narrow-angle light is a direction orthogonal to the optical axis of the spectacle lens L, the narrow-angle light is more appropriately irradiated, and the accuracy is higher. An inspection image C for high inspection can be obtained.

1 ... Lens visual inspection device, 2 ... Enclosure, 4 ... Stage (box), 5 ... (Stage) hole, 7 ... Narrow angle light illumination means, 8 ... Camera, 20 ... Lift ( Distance adjustment means), 24 ... narrow angle optical LED, 26 ... illumination lens, 36 ... camera lens (object side telecentric lens or both side telecentric lens), C ... inspection image, L ... eyeglass lens (inspection) Target lens).

Claims (5)

The inspected lens, from the lateral direction that is a plurality of directions crossing the optical axis of the test object lens, a narrow SumiHikari illumination means directed angle illuminates the narrow angle light is light of 30 ° or less,
A camera having an object-side telecentric lens or a bilateral telecentric lens directed at the inspection target lens and capturing an inspection image,
A box whose inner surface is an anti-reflection surface,
Is equipped with
The camera captures the inspection image in a state where the inspection target lens is illuminated by the narrow-angle light by the narrow-angle light illumination means from the lateral direction .
The box body has holes, and is arranged so that the holes are located on the side opposite to the camera with the lens to be inspected sandwiched therein.
The lens appearance inspection device is characterized in that the narrow-angle light illumination means is arranged on the outer surface of the box body . Further, the lens to be inspected, the narrow-angle optical illumination means, and an enclosure covering the object-side telecentric lens or the bilateral telecentric lens are provided.
The lens appearance inspection device according to claim 1 , wherein the inner surface of the enclosure is an antireflection surface that prevents reflection of the narrow-angle light. The lens appearance inspection apparatus according to claim 1 or 2 , further comprising a distance adjusting means for adjusting the distance between the lens to be inspected and the camera. The lens appearance inspection apparatus according to any one of claims 1 to 3 , wherein the narrow-angle light illuminating means illuminates the entire periphery of the lens to be inspected or a part thereof. The lens appearance inspection apparatus according to any one of claims 1 to 4 , wherein the lateral direction is a direction orthogonal to the optical axis of the lens to be inspected.