JP2009229221A - Optical device defect inspection method and optical device defect inspecting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical device defect inspection method and an optical device defect inspecting apparatus which is not affected by the difference in curvature or the position of an optical device, and which is high-speed and is low cost. <P>SOLUTION: The focus of a photographic means 3 is aligned with a lens under inspection 2, and a light source 5 is moved away from the lens under inspection 2, to a position at which a density difference in a dot pattern 8 within an image of the lens under inspection 2 photographed by the photographic means 3 disappears, thereby defects in the lens under inspection 2 are detected, through image distortion 11 produced inside the image which does not have density difference. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical device defect inspection method and an optical device defect inspection apparatus for detecting a defective portion of an optical device.

  Optical devices such as cameras are composed of various electronic components and optical devices such as lenses. A lens as an optical device must be processed with high precision so that incident light is correctly refracted and travels at each part of the lens, and there is no optical distortion due to surface irregularities or poor internal composition during the manufacturing process. Inspected. Conventionally, in such inspection, the presence or absence of defects from interference fringes caused by transmitting light under the same conditions to the reference lens as a standard and the inspected lens to be inspected and superimposing the respective light beams to interfere with each other An interferometric lens inspection apparatus and method for detecting the above have been used (for example, see Patent Document 1).

  However, since such an inspection apparatus and method require a reference lens that matches the curvature of the lens to be inspected, it is necessary to prepare a reference lens every time the type of lens to be produced changes in multi-product production. Further, since it is necessary to accurately position each lens, it takes time to set, and skill is required to recognize the difference in appearance between the normal part and the defective part of the interference fringes.

  In order to cope with such a problem, as a method for inspecting an optical device without using interference fringes, a defect is detected by detecting the presence or absence of a defect in the optical device by shifting the focus of the imaging means until the black and white pattern of the light source device disappears. A detection method has been proposed (see, for example, Patent Document 2).

There has also been proposed a defect detection apparatus that detects the presence or absence of a defect in an optical device by imaging a lens focused on a light shielding member provided in a light source device with an imaging unit (see, for example, Patent Document 3). ).
JP 2002-357505 A JP-A-8-220021 JP 9-61291 A

  However, the invention as described in Patent Document 2 is for inspection of a continuous plate-like optical device, and an optical device having a large curvature such as a lens has a different appearance depending on the position. The invention as described is not suitable for lens inspection.

  Further, in the invention as described in Patent Document 3, the position of the lens to be inspected must be accurately aligned, and it takes time for readjustment when a lot of inspections are required for a wide variety and a large amount. It was bad.

  The present invention has been made for such a problem, and it is possible to easily detect a defect in an optical device, and to detect a defect in an optical device at a high speed and at a low cost which is not affected by a difference in curvature or the position of the optical device. The object is to provide a defect inspection apparatus.

  In order to achieve the above-mentioned object, the present invention transmits the pattern from a light source device having a pattern formed by a light-shielding portion and a light-transmitting portion, and irradiates one surface of the optical device with light. In an optical device defect inspection method for inspecting a defect of the optical device by imaging the optical device with an imaging unit from a surface opposite to a surface irradiated with light of the optical device, the imaging unit is focused on the optical device The light source device is moved to a position where there is no density difference between the light-shielding part and the light-transmitting part in the image of the optical device imaged by the imaging unit, and the image generated in the image without density difference It is characterized by detecting a defect of the optical device by distortion.

  In the invention, the optical device is a single aspherical convex lens, and the pattern is a dot pattern.

  Further, in the present invention according to the above invention, after the imaging means focuses on the optical device, the focus position is in the axial direction of the optical device or a direction orthogonal to the axial direction and in the vicinity of the optical device. It is also characterized in that the optical device is imaged after being moved.

  According to the present invention, an optical device defect inspection apparatus that inspects the presence or absence of optical distortion due to surface irregularities or internal composition defects of a single aspherical convex lens as an optical device is a CCD camera or the like that images an optical device from one side. A light source that irradiates light to the optical device by transmitting the pattern from the surface opposite to the surface on which the image pickup device picks up the optical device with the pattern comprising the dot pattern formed by the image pickup device, the light shielding portion, and the light transmitting portion The apparatus, the tray positioned between the image pickup means and the light source device and movably provided with a plurality of optical devices, the moving means for moving the light source device, and the image taken by the image pickup means are displayed. And a control means provided with a display means.

  When an optical device is inspected by such an optical device defect inspection apparatus, first, the imaging means is focused on the optical device. Subsequently, the optical device is moved to a position where there is no density difference between the light-shielding part and the light-transmitting part due to the pattern in the image of the optical device that is picked up by the image pickup means and displayed on the display means, so that the entire device has a uniform shading. Move it further away or closer. In this way, it is confirmed whether or not distortion has occurred in the image with the light source device moved. If distortion has occurred, it is recognized that a defect has occurred in the distortion portion.

  As a result, the imaging means, the optical device, and the light source device are each roughly positioned, and even if the curvature of the optical device is different, there is no density difference between the light-shielding part and the light-transmitting part in the entire inspection area, and the entire gray state is uniform. Immediately created, defects can be easily detected, and optical device defect inspection can be performed at high speed and at low cost.

  In the present invention, the imaging means focuses the optical device, moves the focal position to the vicinity of the optical device in the axial direction of the optical device or a direction orthogonal to the axial direction, and then the optical device. Therefore, even if it is difficult to see the defective portion, the focus of the imaging means moves to a position where it can be seen more easily, so that the defect can be easily detected.

  As described above, according to the optical device defect inspection method and the optical device defect inspection apparatus, the light source device including the pattern formed by the light shielding portion and the light transmitting portion is moved from the optical device to a predetermined position. In addition to irradiating light with the pattern transmitted through one surface, the defect of the optical device is detected by imaging the optical device from the surface opposite to the surface irradiated with light. It becomes possible to do.

  Preferred embodiments of an optical device defect inspection method and an optical device defect inspection apparatus according to the present invention will be described below in detail with reference to the accompanying drawings.

  First, the configuration of the optical device defect inspection apparatus according to the present invention will be described. FIG. 1 is a perspective view illustrating a configuration of a defect inspection apparatus, and FIG. 2 is a side view schematically illustrating a state in which an inspection is performed by imaging an optical device.

  As shown in FIG. 1, the defect inspection apparatus 1 can be moved in the Z direction by an image pickup means 3 that picks up an inspected lens 2 of an aspherical convex lens that is an optical device used in a camera or the like, and a moving means 4. A light source device 5, and a tray 6 provided between the imaging means 3 and the light source device 5, on which a plurality of lenses 2 to be inspected are mounted and moved in the X and Y directions by a moving means (not shown).

  Furthermore, the defect inspection apparatus 1 includes a display unit that displays an image captured by the imaging unit 3 and a control unit 7 that controls each part of the defect inspection apparatus 1 such as the moving unit 4.

  The image pickup means 3 is a camera using a CCD or the like, and picks up an image of any one of the inspected lenses 2 supported on a support member (not shown) and placed on the tray 6 from above. The image picked up by the image pickup means 3 is displayed on a monitor 7A which is a display means provided in the control means 7. The image sent from the imaging means 3 to the control means 7 and displayed on the monitor 7A is confirmed by visual observation, or stored in the control means 7 and subjected to image processing by various known image processing techniques.

  The light source device 5 includes a dot pattern 8 that is a pattern formed by a light-shielding portion and a light-transmitting portion, and the dot pattern from the surface opposite to the surface on which the imaging unit 3 images the lens 2 to be inspected to the lens 2 to be inspected. 8 is transmitted and irradiated with light. The light source device 5 is provided so as to be movable in the Z direction perpendicular to the X and Y directions in which the tray 6 moves by a moving means 4 constituted by a known moving mechanism such as a ball screw or a motor.

  When the inspection lens 2 is inspected by the defect inspection apparatus 1 having such a configuration, the imaging means 3 is first focused on the inspection lens 2 as shown in FIG. After the imaging means 3 is focused, the density difference between the light-shielding portion and the light-transmitting portion of the dot pattern 8 reflected on the lens 2 to be inspected in the image taken by the imaging means 3 is eliminated, and a uniform grayscale image as a whole. The light source device 5 is moved away from or closer to the inspected lens 2 to a position where A defect of the lens 2 to be inspected is detected from the distortion of the image generated in the lens 2 to be inspected, which is a uniform gray image.

  As a result, the lens 2 to be inspected, the imaging means 3 and the light source device 5 are each roughly positioned, and even if the curvature of the lens 2 to be inspected is different, the density difference between the light shielding portion and the light transmitting portion in the entire lens 2 to be inspected. An image with a uniform gray state is immediately created without any defects, and defects can be easily detected, and optical device defect inspection can be performed at high speed and at low cost.

  Depending on the type of the lens 2 to be inspected, if it is difficult to see the distortion of the image due to a defect when the focus position of the imaging means 3 is kept on the lens 2 to be inspected, the focus of the imaging means 3 is adjusted to the lens 2 to be inspected. Then, after moving the focal position of the image pickup means 3 to the vicinity of the Z direction that is the axial direction of the lens 2 to be inspected or the X and Y directions orthogonal to the axial direction, the lens 2 to be inspected is imaged for defect inspection. May be. Thereby, even when it is difficult to see the defective portion, the focus of the imaging means 3 moves to a position where it can be seen more easily, so that the detection of the defect becomes easy.

  Next, the optical device defect inspection method according to the present invention will be described. FIG. 3 is a diagram illustrating an image obtained by imaging the optical device with the imaging unit after focusing on the optical device. FIG. 4 is an image obtained by imaging the optical device with the imaging unit when the light source device is moved from the position of FIG. FIG. 5 is a diagram showing an example of an image obtained by imaging a defective optical device.

  When the defect inspection apparatus 1 shown in FIG. 1 inspects a defect of the lens 2 to be inspected, which is an optical device, the tray 6 first moves in the XY direction and is placed on the tray 6 as shown in FIG. One of the placed plurality of inspected lenses 2 is positioned below the imaging means 3. The imaging means 3 prepares for imaging by focusing on the vicinity of the center of the lens 2 to be inspected after the lens 2 to be inspected is positioned immediately below.

  At this time, the imaging unit 3 moves the focal position to the Z direction that is the axial direction of the lens 2 to be inspected or to the vicinity of the X and Y directions that are orthogonal to the axial direction in accordance with the type of the lens 2 to be inspected. The inspection lens 2 may be imaged.

  After the imaging unit 3 is ready for imaging the lens 2 to be inspected, the defect inspection apparatus 1 moves the light source device 5 in the Z direction by the moving unit 4 to move away from or close to the lens 2 to be inspected, and inspect the dot pattern 8. Move away from the focal position of the lens 2. As a result, the image picked up by the image pickup means 3 is obtained from an image in which the density difference between the light shielding portion 8A and the light transmitting portion 8B of the dot pattern 8 shown on the lens 2 to be inspected can be confirmed as shown in the image 10A in FIG. As shown in the image 10B shown in FIG. 4, the light shielding portion 8A and the light transmitting portion 8B appearing on the lens 2 to be inspected are overlapped and changed to a uniform gray image with no density difference.

  At this time, when the defect is generated in the lens 2 to be inspected, the incident light is refracted correctly and does not travel, so that, for example, as shown in an image 10C shown in FIG. As a result, it is recognized that a defect has occurred at the place where the distortion 11 is generated, and it is possible to easily detect the defect even if the lens 2 to be inspected, the imaging means 3 and the light source device 5 are each in a rough positioning. Become.

  The distortion 11 can be confirmed by visually confirming the image by the imaging means 3 displayed on the monitor 7A of the control means 7 or by storing the image in the control means 7 and analyzing it by various image processing techniques. May be recognized. After the presence / absence of a defect in one lens 2 to be inspected is confirmed, the tray 6 is moved in the X and Y directions by a moving means (not shown), and a new lens 2 to be inspected is positioned below the imaging means 3.

  As described above, according to the optical device defect inspection method and the optical device defect inspection apparatus of the present invention, the one surface in a state where the light source device having the light shielding portion and the light transmitting portion is moved from the optical device to a predetermined position. In addition, the optical device defect is detected by imaging the optical device from the surface opposite to the surface irradiated with the light, so that the imaging means, the optical device, and the light source device have rough positioning, respectively. Even if the curvature of the optical device is different, there is no density difference between the light-shielding part and the light-transmitting part in the entire inspection area, and a uniform gray state is instantly created, and defects can be easily detected, and high-speed and inexpensive optics Device defect inspection becomes possible.

  In the present embodiment, the dot pattern 8 formed by the light shielding portion and the light transmitting portion provided in the light source device 5 changes the dot size, pitch, shape, arrangement, etc. depending on the type of optical device to be inspected. May be. As a method for changing the dot pattern 8, any of a mode in which the light source device 5 is provided with a dot display means or a member on which the dot pattern provided in the light source device 5 is formed may be replaced.

The perspective view which showed the structure of the defect inspection apparatus concerning this invention. The side view which showed typically a mode that the optical device was imaged and it test | inspects. The figure which showed the image which imaged the optical device with the imaging means after focusing on the optical device. The figure which showed the image which imaged the optical device with the imaging means when moving the light source device from the position of FIG. The figure which showed an example of the image which imaged the optical device with a defect.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Defect inspection apparatus, 2 ... Lens to be inspected (optical device), 3 ... Imaging means, 4 ... Moving means, 5 ... Light source device, 6 ... Tray, 7 ... Control means, 7A ... Monitor (display means), 8 ... Dot pattern (pattern), 8A ... light-shielding portion, 8B ... translucent portion, 10A, 10B, 10C ... image, 11 ... distortion

Claims (5)

A light source device having a pattern formed by a light-shielding part and a light-transmitting part transmits the pattern to irradiate light on one surface of the optical device. In the optical device defect inspection method for inspecting the defect of the optical device by imaging the optical device from the surface by the imaging means,
Focusing the imaging unit on the optical device, moving the light source device to a position where there is no density difference between the light shielding unit and the light transmitting unit in the image of the optical device imaged by the imaging unit, An optical device defect inspection method, comprising: detecting a defect of the optical device based on distortion of the image generated in the image having no difference.   The optical device defect inspection method according to claim 1, wherein the optical device is a single aspherical convex lens.   The optical device defect inspection method according to claim 1, wherein the pattern is a dot pattern.   The imaging means focuses the optical device, and then moves the focal position in the vicinity of the optical device in the axial direction of the optical device or in a direction orthogonal to the axial direction, and then images the optical device. The optical device defect inspection method according to any one of claims 1, 2, and 3. Imaging means for imaging the optical device from one side;
A light source device comprising a pattern formed by a light-shielding part and a light-transmitting part, wherein the imaging means transmits the pattern from a surface opposite to the surface on which the optical device is imaged and irradiates the optical device with light;
A tray located between the imaging means and the light source device, on which the optical device is placed;
Moving means for moving the light source device;
Control means provided with display means for displaying an image picked up by the image pickup means,
The light source device is moved to a position where there is no difference in density between the light shielding portion and the light transmitting portion in the image of the optical device picked up by the imaging means focused on the optical device and displayed on the display means. An optical device defect inspection apparatus for detecting defects of the optical device by distortion of the image generated in the image having no density difference.

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