JP2009288121A - Apparatus and method for inspecting lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens inspection apparatus capable of downsizing an inspection facility and simplifying inspection processes. <P>SOLUTION: The apparatus emits a light to an inspection target lens 10 and photographs a reflected light therefrom to inspect the lens 10. The apparatus includes a first illuminating means 11 for irradiating the lens 10 the light from a first circular area 17 surrounding an optical axis R of the lens 10, a second illuminating means 12 for irradiating the lens 10 with the light along the optical axis R of the lens 10 inside the first circular area 17, and a third illuminating means 13 for irradiating the lens 10 with the light from a second circular area 18 external to the first circular area 17 in the lens 10 side closer than the first circular area 17. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention mainly relates to a lens inspection apparatus and method that can be used when inspecting the quality of plastic lenses such as scratches, coating defects, and foreign matters.

Conventionally, when inspecting the quality of a plastic lens for scratches, coating defects, foreign matters, etc., visual inspection is performed by an inspection apparatus using a microscope. In this case, because the appearance differs depending on the type of defect, such as scratches on the lens surface, internal foreign matter, coating defects such as coating peeling, etc., an inspection device mainly for detecting scratches and foreign matters and coating Two systems, that is, an inspection apparatus for coating defect inspection for detecting defects, are used. A predetermined number of lenses are arranged on a predetermined inspection table. First, an inspection device for scratches / foreign matter inspection finds and removes scratches and foreign matters from the inspection table, and then an inspection device for coating defect inspection. It has been carried out to find a defective coating and remove it from the inspection table.
JP 2006-329714 A JP 2008-020356 A

  As described above, in the conventional method, since the appearance differs depending on the type of defect such as a flaw on the lens surface, internal foreign matter, coating failure, etc., an inspection apparatus mainly for detecting scratches and foreign matters Two types of inspection devices are used, which are an inspection device for inspecting coating defects to detect coating defects. For this reason, the inspection equipment becomes large and the number of inspection processes increases, which increases the cost required for the inspection.

  The present invention has been made to solve such problems, and an object of the present invention is to provide a lens inspection apparatus and method capable of reducing the inspection equipment and simplifying the inspection process.

In order to achieve the above object, the lens inspection apparatus of the present invention is an apparatus for inspecting a lens by irradiating light onto a lens to be inspected and photographing its reflected light.
First illumination means for irradiating the lens with light from a first annular region around the optical axis of the lens;
Second illumination means for irradiating the lens with light along the optical axis of the lens inside the first annular region;
The gist of the present invention is to include a third illumination unit that irradiates the lens with light from a second annular region outside the first annular region on the lens side with respect to the first annular region.

In order to achieve the above object, the lens inspection method of the present invention is a method for inspecting a lens by irradiating light onto a lens to be inspected and photographing the reflected light.
Irradiating the lens with light from a first annular region around the optical axis of the lens;
Irradiating the lens with light along the optical axis of the lens inside the first annular region,
The gist is to irradiate the lens with light from a second annular region outside the first annular region on the lens side of the first annular region.

  According to the lens inspection apparatus and method of the present invention, the light irradiates the lens from the first annular region around the optical axis of the lens and the optical axis of the lens inside the first annular region. The lens is made up of three light beams: light that irradiates the lens and light that irradiates the lens from the second annular region outside the first annular region on the lens side of the first annular region. Irradiation makes it possible to find scratches on the lens surface, foreign matter inside the lens, coating defects, and the like with a single inspection device and process. Therefore, the inspection equipment can be reduced, the inspection process can be simplified, and the cost required for the inspection can be reduced.

  In the present invention, when the first illuminating means irradiates light by surface light emission from an annular light guide diffusion plate inclined so that at least a part of the light emitting surface faces the optical axis, There is no reflection etc., and scratches on the lens surface, foreign matter inside the lens, coating defects, etc. can be easily found.

  In the present invention, the camera that captures the reflected light from the lens exists on the optical axis, and the second illuminating means includes a half mirror disposed in an inclined manner on the optical axis between the lens and the camera, If the half mirror is configured to include a light source that supplies light from the outside of the optical axis, the light source is arranged along the optical axis of the lens so as not to interfere with shooting with the camera. The lens can be irradiated with light.

  In the present invention, when the brightness of the light from the first illumination means and the second illumination means is set to be higher than the brightness of the light from the third illumination means, the reflection of the light source It is easy to find any scratches on the lens surface, foreign matter inside the lens, and coating defects.

  In the present invention, when the brightness of the light from the first illumination means is set to be higher than the brightness of the light from the second illumination means, there is no reflection of the light source and the lens surface. You can easily find any scratches, foreign matter inside the lens, and poor coating.

  In the present invention, when the inner diameter of the second annular region is set to be 1.8 times or more of the outer diameter of the first annular region, there is no reflection of the light source, and the lens surface is scratched. Any foreign matter inside the lens or defective coating can be easily found.

  Next, the best mode for carrying out the present invention will be described.

  FIG. 1 is a diagram illustrating a configuration of a main part of a lens inspection apparatus according to an embodiment to which the present invention is applied.

  As shown in FIG. 1, the lens 10 inspection apparatus is an apparatus for inspecting the lens 10 by irradiating the lens 10 to be inspected with light and photographing the reflected light. The lens 10 to be inspected is attached to the lens holder 8 and arranged with the back sheet 7 as a background.

  The inspection apparatus for the lens 10 includes a camera 9 that captures reflected light from the lens 10, a first lamp unit 15 that irradiates the lens 10 with illumination light between the camera 9 and the lens 10, and a second lamp unit 15. The lamp unit 16 is provided.

  The lens 10 is attached to the lens holder 8 so that the optical axis R is in the vertical direction in this example. In this example, the lens 10 is arranged so that the convex surface faces the camera 9 side.

  The camera 9 is arranged on the optical axis R so as to photograph the reflected light from the lens 10. The first lamp unit 15 is disposed on the camera 9 side between the camera 9 and the lens 10, and the second lamp unit 16 is disposed on the lens 10 side.

  2 is a view of the first lamp unit 15 as viewed from the lens 10 side, and FIG. 3 is a view of the second lamp unit 16 as viewed from the lens 10 side.

  The first lamp unit 15 has a substantially disk shape, and the first illumination unit of the present invention irradiates the lens 10 with light from the first annular region 17 around the optical axis R of the lens 10. 11 and the second illumination means 12 of the present invention for irradiating the lens 10 with light along the optical axis R of the lens 10 inside the first annular region 17.

  The second lamp unit 16 has a generally ring shape, and is located on the lens 10 side from the first annular region 17 and from the second annular region 18 outside the first annular region 17 to the lens 10. It functions as the third illumination means 13 of the present invention that irradiates light.

  In the first lamp unit 15, the second illumination unit 12 is disposed on the camera 9 side, and the first illumination unit 11 is disposed on the lens 10 side.

  The first lamp unit 15 has an opening 20 formed in the center, and the opening 20 is disposed so as to be coaxial with the optical axis R. The reflected light from the lens 10 passes through the opening 20 and enters the camera 9, and the lens 10 is photographed by the camera 9.

  The first lamp unit 15 is provided with a half mirror 21 inclined on the optical axis R between the lens 10 and the camera 9 so as to close the opening 20. In this example, the half mirror 21 is arranged with an inclination angle of 45 ° with respect to the optical axis R. An LED 22 serving as a light source for supplying light from the outside of the optical axis R to the half mirror 21 is provided in a space 23 that faces the surface of the half mirror 21 facing obliquely 45 °. And the 2nd illumination means 12 is comprised including the said half mirror 21 and LED22.

  The second illuminating means 12 irradiates the lens 10 with light that is irradiated along the optical axis R by reflecting the light of the LED 22 with the half mirror 21. On the other hand, the reflected light of the lens 10 passes through the half mirror 21 and the opening 20 and enters the camera 9. Thereby, both the photographing of the lens 10 by the camera 9 disposed on the optical axis R of the lens 10 and the illumination of the lens 10 by the light along the optical axis R of the lens 10 are realized.

  The first lamp unit 15 has a frame-like portion 24 protruding from the periphery on the lens 10 side, and a large number of LEDs 25 as light sources are attached to the inner surface of the frame-like portion 24 so as to face the center. Yes. An annular light guide diffusion plate 26 that is inclined so that at least a part of the light emitting surface faces the optical axis R is provided inside the LED 25.

  An opening 20 a having the same diameter as the opening 20 is formed in the light guide diffusion plate 26. The light guide diffuser plate 26 is set such that the peripheral portion where the LED 25 is embedded is substantially the same thickness as the frame-shaped portion 24 and gradually decreases in thickness toward the center, that is, the inner peripheral edge of the opening 20a. A light emitting surface including an inclined surface inclined inward is formed on the lens 10 side. The light guide diffusion plate 26 can be formed of, for example, a transparent epoxy resin.

  Thereby, in the first illumination means 11, the surface of the light guide diffuser plate 26 on the lens 10 side (that is, a light emitting surface composed of an inclined surface and a flat portion subsequent thereto) is formed in the first annular region 17. Then, light is emitted by surface emission from the light emitting surface. The light emitted from the first annular region 17 is irradiated toward the lens 10 disposed on the optical axis R, and the lens 10 is illuminated.

  On the other hand, the second lamp unit 16 has a ring-shaped inner peripheral surface formed in the second annular region 18, and a large number of LEDs 28 as light sources are attached in one row over the entire surface. An inner flange 44 that slightly protrudes inward is formed at the top of each LED 28. Further, the lens 10 side of each LED 28 is covered with a cover member 45. Thereby, the light of LED28 is irradiated toward inner side. The light emitted from the LED 28 provided in the second annular region 18 is irradiated toward the lens 10 disposed on the optical axis R, and the lens 10 is illuminated.

  In this apparatus, the light from three irradiation means of the 1st irradiation means 11, the 2nd irradiation means 12, and the 3rd irradiation means 13 is irradiated with respect to the lens 10 arrange | positioned on the optical axis R. FIG. The light emitted from the first irradiating means 11 is surface-emitted from the first annular region 17, and the light having a large irradiation area is irradiated to the lens 10 while being slightly narrowed inward. The light from the second irradiation means 12 travels along the optical axis R and is irradiated onto the lens 10. The light from the third irradiating means 13 is directed inward from the second annular area 18 outside the first annular area 17 on the lens 10 side of the first irradiating means 11 and the second irradiating means 12. Irradiation is performed, and the entire circumference of the lens 10 is irradiated from a position near the side surface of the lens 10.

  In this way, by irradiating the lens 10 with three lights, it is possible to find scratches on the surface of the lens 10, foreign matters inside the lens 10, coating defects, and the like with one system of inspection apparatus and process. Further, there is no reflection of light sources, no interference, etc., and scratches on the surface of the lens 10, foreign matter inside the lens 10, coating defects, etc. can be easily photographed and easily discovered.

Here, the relationship between the distance H ₁ between the camera 9 side of the lens 10 and the first illumination means 11 with respect to the distance H _C between the camera 9 side of the lens 10 and the lens 10 side of the camera 9 is H ₁ ≦ H _C × 0.5 is preferable. Moreover, it is preferable that the relationship between the distance H ₂ between the camera 10 side of the lens 10 and the second illumination unit 12 with respect to the distance H _C is H ₂ ≦ H _C × 0.7. Furthermore, with respect to the distance _{H C,} the relationship between the distance H3 of the camera 9 side and the third illumination unit 13 of the lens 10 is preferably set to _{H 3} ≦ _{H C} × 0.3. By doing so, there is no reflection or interference of the light source, and it is possible to easily detect a flaw on the surface of the lens 10, a foreign matter inside the lens 10, and a coating defect by photographing clearly.

  The inner diameter of the annular light emitting portion formed in the second annular region 18 is set to be 1.8 times or more and 3 times or less the outer diameter of the annular light emitting region formed in the first annular region 17. Is preferred. More preferably, the inner diameter of the annular light emitting portion formed in the second annular region 18 is set to be 2 to 3 times the outer diameter of the annular light emitting region formed in the first annular region 17. By doing so, there is no reflection of the light source, and any defects on the surface of the lens 10, foreign matter inside the lens 10, and defective coating can be easily found.

  Moreover, it is preferable that the light irradiated from the 1st illumination means 11, the 2nd illumination means 12, and the 3rd illumination means 13 is red visible light with a wavelength of 630-680 nm. By doing so, there is no reflection or interference of the light source, and it is possible to easily detect a flaw on the surface of the lens 10, a foreign matter inside the lens 10, and a coating defect by photographing clearly.

  Further, it is preferable that the brightness of the light emitted from the first illumination means 11 and the second illumination means 12 is set higher than the brightness of the light emitted from the third illumination means 13. Furthermore, it is preferable to set so that the brightness of light by the first illumination means 11 is higher than the brightness of light by the second illumination means 12. By doing so, there is no reflection of the light source, and it is possible to easily detect flaws on the surface of the lens 10, foreign matters inside the lens 10, and defective coating by photographing clearly.

At this time, it is preferable that the luminance of the light by the first illumination unit 11 is set within 656 ± 50 cd / m ² , and the luminance of the light by the second illumination unit 12 is set within 525 ± 50 cd / m ² . It is preferable to set the luminance of light by the third illumination means 13 within 394 ± 50 cd / m ² .

  Moreover, it is preferable that the color of the back sheet 7 arrange | positioned on the opposite side to the camera 9 of the lens 10 shall be black and glossless. By doing so, there is no reflection or interference of the light source, and it is possible to easily detect a flaw on the surface of the lens 10, a foreign matter inside the lens 10, and a coating defect by photographing clearly.

  FIG. 4 is a diagram showing an example of the entire configuration of the inspection line including the inspection device 30 for the lens 10.

  This inspection line includes a defective lens from the above-described inspection device 30, a supply device 31 that supplies the tray-shaped lens holder 8 to the inspection device 30, and the lens holder 8 that has finished the inspection by the inspection device 30. A pickup device 32 that picks up and removes and a stocker 33 that stocks the lens holder 8 discharged from the pickup device 32 are provided.

  In this example, the lens holder 8 has a rectangular tray shape, and the lenses 10 to be inspected are set in a vertical and horizontal arrangement. Such lens holders 8 are stacked and stocked on the supply device 31, and are supplied to the inspection device 30 one by one by the loader device 34.

  The lens holder 8 supplied to the inspection device 30 is placed on the XY table 35. The XY table 35 is moved and controlled by an XY movement control unit 36 so that the optical axis R of each lens 10 arranged in the lens holder 8 is sequentially aligned with the optical axis of the camera 9. The first illumination unit 11 and the second illumination unit 12 of the first lamp unit 15 and the third illumination unit 13 of the second lamp unit 16 are controlled by the illumination controller 37. The camera 9 is controlled by a computer device 38 as control means.

  Then, the movement of the XY table 35 is controlled, and when the optical axis R of the lens 10 is on the optical axis of the camera 9, photographing is performed by the camera 9. When shooting is completed, the movement control of the XY table 35 is repeated for the next shooting of the lens 10.

  The image taken by the camera 9 is captured by the computer device 38 and subjected to image analysis processing to detect defects such as scratches on the surface of the lens 10, foreign matter inside the lens 10, coating defects, and the like. Remember. In addition, information such as the captured image, the position information of the defective lens, and the content of the defect is displayed on the monitor 39.

  When photographing and analysis of all the lenses 10 on the lens holder 8 are completed, the lens holder 8 is moved onto the pickup device 32. The pickup device 32 includes a removal arm 40 that picks up and removes a defective lens, and an XY stage 41 that moves the removal arm 40. Based on the defective lens position information acquired from the computer device 38, the XY controller 42 controls the XY stage 41 to move the removal arm 40 to the position of the defective lens. Picking up and removing from the lens holder 8 is performed.

  The lens holder 8 from which the defective lens is removed is moved to the stocker 33 and stocked. As described above, the lens 10 is automatically inspected and defective products are picked up.

  As described above, according to the inspection apparatus 30 and the method for the lens 10 of the present embodiment, the light irradiated to the lens 10 from the first annular region 17 around the optical axis R of the lens 10, and the first The light that irradiates the lens 10 along the optical axis R of the lens 10 inside the one annular region 17, and the outside of the first annular region 17 on the lens 10 side of the first annular region 17. By irradiating the lens 10 with three lights, that is, the light irradiating the lens 10 from the second annular region 18, one system of inspection device for scratches on the surface of the lens 10, foreign matters inside the lens 10, coating defects, etc. It became possible to discover in 30 and steps. Therefore, the inspection equipment can be reduced, the inspection process can be simplified, and the cost required for the inspection can be reduced.

  In the case where the first illuminating means 11 irradiates light by surface light emission from the annular light guide diffusion plate 26 inclined so that at least a part of the light emitting surface faces the optical axis R, a reflection of the light source. No flaws or the like can be found, and scratches on the surface of the lens 10, foreign matter inside the lens 10, coating defects, etc. can be easily found.

  The camera 9 that captures the reflected light from the lens 10 exists on the optical axis R, and the second illumination means 12 is a half arranged in an inclined manner on the optical axis R between the lens 10 and the camera 9. When the mirror 21 and the LED 22 that supplies light from the outside of the optical axis R to the half mirror 21 are configured, the LED 22 is arranged so as not to interfere with the photographing with the camera 9. Light can be irradiated to the lens 10 along the optical axis R of the lens 10.

  When the brightness of the light from the first illumination means 11 and the second illumination means 12 is set to be higher than the brightness of the light from the third illumination means 13, the reflection of the light source, etc. There are no defects, and scratches on the surface of the lens 10, foreign matter inside the lens 10, and defective coating can be easily found.

  When the brightness of the light from the first illumination means 11 is set to be higher than the brightness of the light from the second illumination means 12, there is no reflection of the light source and the surface of the lens 10 Scratches, foreign matter inside the lens 10, and coating defects can all be easily found.

  When the inner diameter of the second annular region 18 is set to be 1.8 times or more the outer diameter of the first annular region 17, there is no reflection of the light source, and scratches on the surface of the lens 10, Both foreign matter and coating defects inside the lens 10 can be easily found.

  In the inspection apparatus 30 shown in FIG. 1, red visible light is emitted from each of the first illumination means 11, the second illumination means 12, and the third illumination means 13, and the position of the lens 10 on the camera 9 side and each illumination means. Table 1 shows the result of a shooting test performed with the distance between and.

Table 1 shows that the distance H ₃ between the lens 10 and the third illumination means 13 is 17 mm and 30 mm, and the distance H ₁ between the lens 10 and the first illumination means 11 is 33 mm and 45 mm. As a result of setting the distance H2 to the _second illumination means 12 to 49 mm and 61 mm, the incident light that is direct light from the camera 9 side and the distance to the lens 10 to 33 mm, the direct light from the camera 9 side is used. The result of setting the distance from the lens 10 to 33 mm by using a certain incident light in combination with a diffusion plate is shown.

The best results are obtained when the distance H ₃ is 17 mm with the third illumination means 13, the distance H ₁ is 33 mm with the first illumination means 11, and the distance H ₂ is 49 mm with the second illumination means 12. It was. Thereby, it turns out that a favorable result is obtained when the 1st illumination means 11, the 2nd illumination means 12, and the 3rd illumination means 13 are used together.

First illumination means 11, a second illumination means 12, in combination with a third illuminating means 13, the distance _{H 1} 33 mm, the distance _{H 2} 49 mm, the distance _{H 3} and 17 mm, the first lighting unit 11 Table 2 shows the results of a photographing test when the outer diameter of the light emitting surface is 55 mm, 65 mm, and 105 mm, and the inner diameter of the light emitting portion of the third illumination unit 13 is 60 mm, 110 mm, 140 mm, and 170 mm.

The best results were obtained when the outer diameter of the light emitting surface of the first illuminating means 11 was 65 mm and the inner diameter of the light emitting part of the third illuminating means 13 was 140 mm.

First illumination means 11, a second illumination means 12, in combination with a third illuminating means 13, the distance _{H 1} 33 mm, the distance _{H 2} 49 mm, the distance _{H 3} and 17 mm, the first lighting unit 11 Table 3 shows the results of a photographing test performed by changing the type of light emitted when the outer diameter of the light emitting surface was 65 mm and the inner diameter of the light emitting portion of the third illumination unit 13 was 140 mm. The best results were obtained with red visible light having a wavelength of 630 to 680 nm.

First illumination means 11, a second illumination means 12, in combination with a third illuminating means 13, the distance _{H 1} 33 mm, the distance _{H 2} 49 mm, the distance _{H 3} and 17 mm, the first lighting unit 11 Table 4 shows the results of a photographing test performed by changing the luminance level of light in each illumination unit when the outer diameter of the light emitting surface was 65 mm and the inner diameter of the light emitting portion of the third illumination unit 13 was 140 mm.

The level is 16 steps from 1 to 16, and the brightness at the maximum level 16 is 2100 cd / m ² (measured immediately after irradiation at a room temperature of 20 ° C. at a distance of 50 mm. The first illumination means 11 is level 5 (about 656 cd / m ²⁾ . m ² ), the second illumination means 12 was level 4 (about 525 cd / m ² ), and the third illumination means 13 was level 3 (about 394 cd / m ² ), the best results were obtained.

The results of a shooting test in which the first illumination means 11, the second illumination means 12, and the third illumination means 13 are used together and the color of the backsheet 7 disposed on the opposite side of the lens 10 from the camera 9 is changed. Table 5 shows. The best results were obtained with black and no gloss.

  In addition, the said embodiment is only what showed one Embodiment of this invention, and this invention is the meaning containing various modifications. For example, the first illumination unit 11 and the second illumination unit 12 may be individual lamp units. The light source is not limited to the LED, and other light sources may be used. The lens 10 to be inspected is not limited to a plastic lens. In addition, various modifications can be added as necessary.

It is a figure explaining the structure of the principal part of the inspection apparatus of the lens to which this invention is applied. It is the figure which looked at the 1st lamp unit from the lens side. It is the figure which looked at the 2nd lamp unit from the lens side. It is a figure which shows an example of the whole structure of an inspection line.

Explanation of symbols

7: Back sheet 8: Lens holder 9: Camera 10: Lens 11: First illumination means 12: Second illumination means 13: Third illumination means 15: First lamp unit 16: Second lamp unit 17: Second 1 annular region 18: second annular region 20: opening 20a: opening 21: half mirror 22: LED
23: Space 24: Frame portion 25: LED
26: Light guide diffuser plate 28: LED
30: Inspection device 31: Supply device 32: Pickup device 33: Stocker 34: Loader device 35: XY table 36: XY movement control unit 37: Lighting controller 38: Computer device 39: Monitor 40: Removal arm 41: XY stage 42: XY controller 44: inner flange 45: cover member

Claims (7)

An apparatus for inspecting a lens by irradiating light onto a lens to be inspected and photographing the reflected light,
First illumination means for irradiating the lens with light from a first annular region around the optical axis of the lens;
Second illumination means for irradiating the lens with light along the optical axis of the lens inside the first annular region;
And a third illumination means for irradiating the lens with light from a second annular region outside the first annular region on the lens side of the first annular region. Inspection device.   2. The lens inspection apparatus according to claim 1, wherein the first illuminating means irradiates light by surface light emission from an annular light guide diffusion plate inclined so that at least a part of the light emitting surface faces the optical axis. The camera that captures the reflected light from the lens exists on the optical axis,
The second illuminating means includes a half mirror disposed in an inclined manner on the optical axis between the lens and the camera, and a light source that supplies light to the half mirror from outside the optical axis. The lens inspection device according to claim 1 or 2.   The lens according to any one of claims 1 to 3, wherein the brightness of light by the first illumination means and the second illumination means is set to be higher than the brightness of light by the third illumination means. Inspection equipment.   The lens inspection apparatus according to any one of claims 1 to 4, wherein the brightness of the light emitted from the first illumination means is set higher than the brightness of the light emitted from the second illumination means.   The lens inspection device according to claim 1, wherein an inner diameter of the second annular region is set to be 1.8 times or more of an outer diameter of the first annular region. A method of inspecting a lens by irradiating light onto a lens to be inspected and photographing the reflected light,
Irradiating the lens with light from a first annular region around the optical axis of the lens;
Irradiating the lens with light along the optical axis of the lens inside the first annular region,
A lens inspection method comprising irradiating light to a lens from a second annular region outside the first annular region on the lens side with respect to the first annular region.

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