Appearance inspection apparatus, appearance inspection method, and appearance inspection program

Abstract

Provided are a visual inspection device, a visual inspection method, and a visual inspection program that make it possible to accurately evaluate a subject having optical transparency.　The present invention is provided with: a mounting part (10) on which a lens L is mounted; an illumination unit that is capable of irradiating the mounting part (10) with illumination light having a plurality of shapes; an image capturing unit (30) that captures an image of the mounting part (10); a driving unit that changes the relative positions of the mounting part (10), the illumination unit (20), and the image capturing unit (30); and a processor that performs control for causing the image capturing unit (30) to capture an image of the lens L a plurality of times, while changing the relative positions and the shape of the illumination light. The processor causes the image capturing unit (30) to capture an image of the lens L including reflected light formed by reflection of the illumination light by the lens L, as well as an image of the lens L including transmitted light formed by transmission of the illumination light through the lens L.

Description

Technical Field

[0001] The present invention relates to an appearance inspection apparatus, an appearance inspection method, and an appearance inspection program.

Background Art

[0002] Patent Document 1 discloses an optical inspection method in which an object is illuminated from a plurality of different illumination directions, images of the object acquired by imaging for each of the plurality of illumination directions by an imaging means are subjected to image processing by a control device, and the presence or absence of a defect in the object is determined.

[0003] Patent Document 2 discloses a work inspection apparatus for inspecting the appearance of a work including a curved surface. This work inspection apparatus includes a line sensor camera having a line-shaped imaging range along an orthogonal direction orthogonal to a predetermined direction of the curved surface, a telecentric lens integrally attached to the line sensor camera for causing light parallel to the optical axis of the line sensor camera to enter the line sensor camera, side illumination means for emitting light from a side position outside the front of the imaging range in the predetermined direction of the curved surface toward the imaging range, rotation means for relatively rotating the work along the predetermined direction of the curved surface with respect to the line sensor camera and the side illumination means, and inspection control means for generating an inspection image during side illumination by causing the line sensor camera to image the imaging range while relatively rotating the work with respect to the line sensor camera and the side illumination means and causing the side illumination means to emit light.

[0004] Patent Document 3 discloses a method for distinguishing defects on the front and back of a color filter using a reflection system light source above the color filter surface, a reflection optical system of an inspection camera, and a transmission optical system of a transmission system inspection camera above the color filter surface.

[0005] Patent Document 4 discloses an appearance inspection apparatus having a plurality of types of light sources capable of irradiating inspection light onto an imaging surface that is at least one of the inner peripheral surface and the outer peripheral surface of a cylindrical inspection object, and an imaging inspection unit that images the inspection object and inspects the appearance of the inspection object based on an image of an imaging inspection range corresponding to a part in the circumferential direction of the imaging surface among the captured images. This appearance inspection apparatus has a positioning mechanism having an arrangement unit that positions the inspection object at an inspection position, and a rotation unit that rotates the inspection object positioned at the inspection position around the central axis of the cylinder. The light source includes a bar light source having a pair of linear light emitting units having an optical axis parallel to the optical axis of the imaging inspection unit and extending parallel to each other, and a coaxial light source having the same optical axis as the optical axis of the imaging inspection unit and positioned between the pair of light emitting units. The positioning mechanism positions the inspection object at the inspection position in an imaging arrangement where the optical axis of the imaging inspection unit is orthogonal to the tangent of the imaging surface of the inspection object within the imaging inspection range, and a pair of light emitting units of the bar light source are in a position that does not overlap with the imaging surface within the imaging inspection range and in the optical axis direction of the imaging inspection unit, and the central axis is inclined at a predetermined angle with respect to the optical axis of the imaging inspection unit. The imaging inspection unit images the inspection object in synchronization with the rotation of the inspection object by the rotation unit.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0007] The visual inspection of a light-transmissive member such as a lens or a film has been performed by visual observation. Although methods for automating the visual inspection have been proposed as in Patent Documents 1 and 3, it is difficult to detect various types of defects that may occur in the object to be inspected by these methods. Patent Documents 2 and 4 do not assume the inspection of a light-transmissive member.

[0008] An object of the present invention is to highly accurately evaluate a light-transmissive object to be inspected.

Means for Solving the Problem

[0009] An appearance inspection apparatus according to an aspect of the present invention includes It is rotatably supported on the inner wall of the through hole of the abutment, a holding unit for holding an object to be inspected, a rotation mechanism that rotates the holding portion around a rotation axis extending in the direction of the through hole, and is disposed on a first side that is one side in the direction of the through hole from the holding portion, the above holding unit the subject held therein an imaging unit for imaging, and an imaging unit driving mechanism that changes the position of the imaging unit with respect to the abutment and the imaging direction, a flat light source disposed on the first side and capable of irradiating the subject held by the holding portion with planar light, a flat light source driving mechanism that changes the position of the flat light source with respect to the abutment and the irradiation direction with respect to the subject held by the holding portion, a line light source disposed on a second side that is opposite to the first side from the holding portion and capable of irradiating the subject held by the holding portion with linear light, a line light source driving mechanism that changes the position of the line light source with respect to the abutment and the irradiation direction with respect to the subject held by the holding portion, control for driving the rotation mechanism, the imaging unit driving mechanism, the flat light source driving mechanism, and the line light source driving mechanism, control for operating the flat light source and the line light source, and control for operating the imaging unit a processor for performing, and the processor causes Planar light from the flat light source when the rotation mechanism is driven and the subject held by the holding portion is at a plurality of rotation positions the object to be inspected including reflected light reflected by the object to be inspected and Linear light from the line light source the object to be inspected including transmitted light transmitted through the object to be inspected to be imaged by the imaging unit.

[0011] An appearance inspection method according to an aspect of the present invention is It is rotatably supported on the inner wall of the through hole of the abutment, a holding unit for holding an object to be inspected, a rotation mechanism that rotates the holding portion around a rotation axis extending in the direction of the through hole, and is disposed on a first side that is one side in the direction of the through hole from the holding portion, the above holding unit the subject held therein an imaging unit for imaging, and an imaging unit driving mechanism that changes the position of the imaging unit with respect to the abutment and the imaging direction, a flat light source disposed on the first side and capable of irradiating the subject held by the holding portion with planar light, a flat light source driving mechanism that changes the position of the flat light source with respect to the abutment and the irradiation direction with respect to the subject held by the holding portion, a line light source disposed on a second side that is opposite to the first side from the holding portion and capable of irradiating the subject held by the holding portion with linear light, a line light source driving mechanism that changes the position of the line light source with respect to the abutment and the irradiation direction with respect to the subject held by the holding portion an appearance inspection method for inspecting the appearance of the object to be inspected using, A drive mechanism control step for driving the rotation mechanism, the imaging unit drive mechanism, the flat light source drive mechanism, and the line light source drive mechanism; a light source activation control step for activating the flat light source and the line light source; and an imaging control step for activating the imaging unit. Using the drive mechanism control step, the light source activation control step, and the imaging control step, when the subject held by the holding unit is located at a plurality of rotational positions by driving the rotation mechanism, planar light from the flat light source the object to be inspected including reflected light reflected by the object to be inspected of a plurality of captured images and linear light from the line light source the object to be inspected including transmitted light transmitted through the object to be inspected of a plurality of captured images and Perform a plurality of rotational position captured image acquisition steps to acquire is such that.

[0013] An appearance inspection program according to an aspect of the present invention is is rotatably supported on the inner wall of the through hole of the base, a holding unit for holding an object to be inspected, a rotation mechanism for rotating the holding unit around a rotation axis extending in the direction of the through hole, and disposed on a first side which is one side in the direction of the through hole rather than the holding unit, the above holding unit the subject held an imaging unit for imaging, and an imaging unit drive mechanism for changing the position and imaging direction of the imaging unit with respect to the base, a flat light source disposed on the first side and capable of irradiating the subject held by the holding unit with planar light, a flat light source drive mechanism for changing the position of the flat light source with respect to the base and the irradiation direction with respect to the subject held by the holding unit, a line light source disposed on a second side which is the side opposite to the first side rather than the holding unit and capable of irradiating the subject held by the holding unit with linear light, and a line light source drive mechanism for changing the position of the line light source with respect to the base and the irradiation direction with respect to the subject held by the holding unit, an appearance inspection program for inspecting the appearance of the object to be inspected using, a drive mechanism control step for driving the rotation mechanism, the imaging unit drive mechanism, the flat light source drive mechanism, and the line light source drive mechanism; a light source activation control step for activating the flat light source and the line light source; and an imaging control step for activating the imaging unitwhich causes a computer to execute, Using the drive mechanism control step, the light source activation control step, and the imaging control step, when the subject held by the holding unit is located at a plurality of rotational positions by driving the rotation mechanism, a plurality of captured images of the subject including reflected light reflected by the subject of planar light from the flat light source, and a plurality of captured images of the subject including transmitted light transmitted through the subject of linear light from the line light source are acquired, and a plurality of rotational position captured image acquisition step is performed is as follows.

Advantages of the Invention

[0015] According to the present invention, it is possible to highly accurately evaluate a subject having light transmissivity.

Brief Description of the Drawings

[0016]

Figure 1

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Figure 11

Best Mode for Carrying Out the Invention

[0017] FIG. 1 is a schematic diagram showing a schematic configuration of an appearance inspection apparatus 100 according to an embodiment of the present invention. In FIG. 1, a direction X, a direction Y orthogonal to the direction X, and a direction Z orthogonal to both the direction X and the direction Y are shown. For example, the appearance inspection apparatus 100 is constructed such that the direction Z coincides with the vertical direction and the opposite direction thereof.

[0018] The appearance inspection apparatus 100 includes a base 11 fixed at a predetermined position in the direction Z. A through hole penetrating in the direction Z is formed in the base 11, and a substantially cylindrical mounting portion 10 (an example of a holding portion in this specification) is rotatably supported on the inner wall of this through hole. The mounting portion 10 is a member on which a lens L as a subject to be inspected for appearance by the appearance inspection apparatus 100 is mounted. The mounting portion 10 is rotatably supported about a rotation axis extending in the direction Z. In a state where the lens L is mounted on the mounting portion 10, the optical axis K of the lens L and the rotation center of the mounting portion 10 are configured to coincide.

[0019] The base 11 is provided with a rotation mechanism 10A for rotating the mounting portion 10. The mounting portion 10 is configured to be rotatable about the rotation axis by the rotation mechanism 10A. The rotation angle of the mounting portion 10 is defined as the position of the mounting portion 10.

[0020] The appearance inspection apparatus 100 further includes a flat light source 21 constituting a surface light source, and a flat light source drive mechanism 21A for moving the flat light source 21 in the directions X and Z and rotating it about an axis Ax1 extending in the direction Y. The flat light source 21 and the flat light source drive mechanism 21A are disposed on one side (the upper side, the first side in the figure) of the base 11 in the direction Z.

[0021] The flat light source 21 irradiates the placement portion 10 with planar light (surface light). The configuration of the flat light source 21 is not limited as long as it can irradiate surface light. For example, the flat light source 21 can be composed of an LED (Light Emitting Diode) and a light guide, or composed of a planar organic EL (Electro Luminescence), etc.

[0022] Hereinafter, a combination of the position of the flat light source 21 in the direction X, the position of the flat light source 21 in the direction Z, and the rotation angle around the axis Ax1 of the flat light source 21 is defined as the position of the flat light source 21.

[0023] The appearance inspection device 100 further includes a line light source 22 that constitutes a line light source, and a line light source drive mechanism 22A that moves the line light source 22 in the directions X and Z and rotates it around an axis Ax2 extending in the direction Y. The line light source 22 and the line light source drive mechanism 22A are arranged on the other side in the direction Z (the lower side, the second side in the figure) than the base 11.

[0024] The line light source 22 irradiates the placement portion 10 with linear light (line light) extending in the direction Y. The configuration of the line light source 22 is not limited as long as it can irradiate line light. For example, the line light source 22 can be composed of a metal halide lamp and a light guide, or composed of an LED and a light guide, etc.

[0025] Hereinafter, a combination of the position of the line light source 22 in the direction X, the position of the line light source 22 in the direction Z, and the rotation angle around the axis Ax2 of the line light source 22 is defined as the position of the line light source 22.

[0026] The appearance inspection device 100 further includes a placement unit 10, an imaging unit 30 that images the lens L placed thereon, a spot light source 23 that constitutes a point light source and is fixed to the imaging unit 30, and an imaging unit drive mechanism 30A that moves the imaging unit 30 in the directions X and Z and rotates it around the axis Ax extending in the direction Y. The imaging unit 30, the spot light source 23, and the imaging unit drive mechanism 30A are arranged on one side (the upper side, the first side in the figure) of the base 11 in the direction Z.

[0027] The imaging unit 30 includes an imaging element and an imaging optical system, and images the lens L placed on the placement unit 10 through the imaging optical system.

[0028] The spot light source 23 irradiates the placement unit 10 with dot-shaped light (dot light). The configuration of the spot light source 23 is not limited as long as it irradiates dot-shaped light. For example, the spot light source 23 can use those including a laser or an LED and an irradiation optical system. The spot light source 23 is fixed to the imaging unit 30 in a state where its optical axis intersects with the optical axis of the imaging unit 30.

[0029] The imaging unit drive mechanism 30A moves or rotates the imaging unit 30 to move or rotate the spot light source 23 fixed to the imaging unit 30. Therefore, the imaging unit drive mechanism 30A can also be referred to as a spot light source drive mechanism that moves the spot light source 23 in the directions X and Z and rotates it around the axis Ax3.

[0030] Hereinafter, a combination of the position of the imaging unit 30 in the direction X, the position of the imaging unit 30 in the direction Z, and the rotation angle of the imaging unit 30 around the axis Ax3 is defined as the position of the imaging unit 30. Also, a combination of the position of the spot light source 23 in the direction X, the position of the spot light source 23 in the direction Z, and the rotation angle of the spot light source 23 around the axis Ax3 is defined as the position of the spot light source 23.

[0031] The flat light source 21, the line light source 22, and the spot light source 23 constitute an illumination unit 20 capable of irradiating the placement unit 10 with light of a plurality of shapes (linear light as the first shape, planar light as the second shape, and dot light as the third shape).

[0032] Although details will be described later, when performing an appearance inspection of the lens L for a predetermined evaluation item, any one of the flat light source 21, the line light source 22, and the spot light source 23 is controlled to be in a state of irradiating light. Hereinafter, among the flat light source 21, the line light source 22, and the spot light source 23, the position of the light source controlled to be in a state of irradiating the placement unit 10 is defined as the position of the illumination unit 20. In addition to the light source controlled to be in a state of irradiating the placement unit 10 in the following description, light may be irradiated from another light source. For example, in the inspection of the line light source 22, the flat light source 21 may be used as auxiliary illumination for specifying the position of the outer peripheral portion of the lens.

[0033] The flat light source drive mechanism 21A, the line light source drive mechanism 22A, the imaging unit drive mechanism 30A, and the rotation mechanism 10A constitute drive units that change the relative positions of the placement unit 10, the illumination unit 20, and the imaging unit 30. The flat light source drive mechanism 21A, the line light source drive mechanism 22A, and the imaging unit drive mechanism 30A constitute drive mechanisms that move the illumination unit 20 and the imaging unit 30 relative to the placement unit 10.

[0034] The appearance inspection apparatus 100 further includes a general control unit 40 that performs overall control, a position control unit 41, and an illumination control unit 42. Each of the general control unit 40, the position control unit 41, and the illumination control unit 42 includes a processing unit that performs various processes, and a memory including a RAM (Random Access Memory) and a ROM (Read Only Memory). The hardware structure of the processing unit is various processors as shown below.

[0035] Various processors include the CPU (Central Processing Unit), which is a general-purpose processor that executes software (programs) to perform various processes, a programmable logic device (PLD), such as an FPGA (Field Programmable Gate Array), which is a processor whose circuit configuration can be changed after manufacturing, or a dedicated electric circuit, such as an ASIC (Application Specific Integrated Circuit), which is a processor having a circuit configuration specifically designed to execute specific processes.

[0036] The processing unit may be composed of one of these various processors, or may be composed of a combination of two or more processors of the same or different types (for example, a plurality of FPGAs, or a combination of a CPU and an FPGA). Each of the processing units of the overall control unit 40, the position control unit 41, and the illumination control unit 42 is configured by using one or more of the above various processors as a hardware structure. More specifically, the hardware structure of these various processors is an electric circuit (circuitry) that combines circuit elements such as semiconductor elements. The overall control unit 40, the position control unit 41, and the illumination control unit 42 may have a configuration in which the processing unit, the RAM, and the ROM are shared.

[0037] The position control unit 41 independently drives the imaging unit drive mechanism 30A, the flat light source drive mechanism 21A, the line light source drive mechanism 22A, and the rotation mechanism 10A according to commands from the overall control unit 40. The position control unit 41 operates the imaging unit drive mechanism 30A to control the positions of the imaging unit 30 and the spot light source 23. The position control unit 41 operates the flat light source drive mechanism 21A to control the position of the flat light source 21. The position control unit 41 operates the line light source drive mechanism 22A to control the position of the line light source 22. The position control unit 41 operates the rotation mechanism 10A to control the position of the placement unit 10.

[0038] The lighting control unit 42 controls the flat light source 21, the line light source 22, and the spot light source 23 individually according to commands from the overall control unit 40.

[0039] When performing an appearance inspection of the lens L placed on the placement unit 10, the overall control unit 40 performs at least a transmitted light inspection process and a first reflected light inspection process. Depending on the structure of the lens L, the overall control unit 40 additionally performs a second reflected light inspection process. Hereinafter, the details of each inspection process will be described.

[0040] (Transmitted Light Inspection Process) The transmitted light inspection process includes position control for controlling the positions of the line light source 22 and the imaging unit 30 to positions determined according to the lens information (information regarding the structure such as shape and curvature) of the lens L, activation of the line light source 22 and the imaging unit 30 whose positions are determined by this position control, and imaging control for imaging the lens L irradiated with line light from the line light source 22 a plurality of times by the imaging unit 30 while rotating the placement unit 10, and evaluation processing for evaluating the first evaluation item of the lens L based on the plurality of imaging images obtained by this imaging control.

[0041] The first evaluation items are scratches (linear defects), bumps (dot-like or circular defects), cloudiness, and stains which are complexes of these defects, etc., which are widely known as lens defects. Scratches, bumps, cloudiness, and stains are major lens defects, but other evaluation items may also be used.

[0042] The evaluation regarding the first evaluation item of the lens L means, for example, ranking the lens L based on the feature amounts (length, width, etc.) of the scratch areas detected from the captured image, ranking the lens L based on the feature amounts (size, etc.) of the foreign matter areas detected from the captured image, ranking the lens L based on the feature amounts (area, luminance, etc.) of the fog areas detected from the captured image, and ranking the lens L based on the feature amounts (size, etc.) of the stain areas detected from the captured image. Ranking means classifying the lens L into ranks such as good products, defective products, and products that require reinspection. The size can be calculated, for example, by (long side + short side) / 2 of the smallest rectangle surrounding the defect. Also, as the size, the area of the smallest rectangle surrounding the defect may be calculated.

[0043] Scratches, foreign matter, fog, and stains are visually recognized by irradiating light from one side in the optical axis direction of the lens L and observing the transmitted light of this light from the other side in the optical axis direction of the lens L.

[0044] In the captured image of the lens L obtained by the above imaging control, in the area where the line light source 22 is not reflected, if there are no scratches, foreign matter, fog, or stains in that area, the luminance is low and uniform. If there are scratches, foreign matter, fog, or stains in this area, the luminance becomes high at the location of the defect. Therefore, by detecting the portion where the luminance is higher than the threshold value in the area of the captured image that does not include the line light source 22 (the area where the line light source 22 is not reflected), the presence or absence of scratches, foreign matter, fog, or stains can be determined. In the transmitted light inspection process, based on such an idea, scratches, foreign matter, fog, or stains are detected, and the evaluation regarding the first evaluation item is performed based on the feature amounts of each defect.

[0045] FIG. 2 is a schematic diagram showing an example of the positional relationship among the imaging unit 30, the placement unit 10, and the line light source 22 during the transmitted light inspection process.

[0046] In the transmitted light inspection process, the overall control unit 40 performs the above-described position control so as to reach the state ST1 in FIG. 2. In this state ST1, the placement unit 10 is rotated, and the lens L is imaged when the placement unit 10 is at each rotation position. Hereinafter, as an example, the imaging of the lens L is performed once every 12 degrees of rotation of the placement unit 10, and it is assumed that the placement unit makes one full rotation. That is, in the above-described imaging control, a total of 29 imaging operations are performed. Note that the imaging interval (angle) and the number of imaging times can be arbitrarily set. Also, the placement unit does not necessarily have to make one full rotation.

[0047] In the transmitted light inspection process, the overall control unit 40 further performs the above-described position control so as to reach the state ST2 in FIG. 2. In this state ST2, the placement unit 10 is rotated once, and the lens L is imaged when the placement unit 10 is at each rotation position (rotation positions that are N times 12 degrees (N = 1 to 29)).

[0048] The overall control unit 40 detects defects in the first evaluation item from each of the 58 imaging images obtained by the 29 imaging operations in state ST1 and the 29 imaging operations in state ST2, and ranks the lens L based on the detection results.

[0049] The state ST1 shown in FIG. 2 is a state in which the optical axis of the imaging unit 30 is parallel to the optical axis K of the lens L (in the example of FIG. 2, the positions in the X and Y directions of both optical axes coincide), and the irradiation direction of the line light from the line light source 22 is inclined with respect to the optical axis K.

[0050] FIG. 3 shows the irradiation range AR1 of the line light on the lens L in the state ST1. As shown in FIG. 3, in the state ST1, the line light is obliquely irradiated on the central portion (second region) of the lens L in the X direction. The central portion is a region that includes the optical axis of the lens L and has a width in the X direction. By rotating the placement unit 10 once in the state ST1, the entire inspection target region (specifically, the region of the effective diameter) of the lens L is irradiated with the line light.

[0051] The state ST2 shown in FIG. 2 is a state in which only the position of the line light source 22 is changed with respect to the state ST1. FIG. 3 shows the irradiation range AR2 of the line light on the lens L in the state ST2. As shown in FIG. 3, in the state ST2, the line light is obliquely irradiated on the region (first region) at one end on one side in the direction X of the lens L. By rotating the placement unit 10 once in the state ST2, the line light will be irradiated on the entire peripheral region on the outer side in the radial direction of the inspection target region of the lens L.

[0052] In the example of FIG. 3, the irradiation range AR1 reaches from one end to the other end in the direction Y of the lens L, but it is not limited to this. For example, as in the state ST1a of FIG. 3, the irradiation range AR1 may be set at the center of the lens L in the directions X and Y. Even in this case, by rotating the placement unit 10 once in the state ST1a and rotating the placement unit 10 once in the state ST2, the entire inspection target region of the lens L can be irradiated with the line light.

[0053] Also, the irradiation range AR2 may be set, for example, between one end on one side in the direction X of the lens L and the center, as in the state ST2a of FIG. 3. Even in this case, by rotating the placement unit 10 once in the state ST1 or state ST1a and rotating the placement unit 10 once in the state ST2a, the entire inspection target region of the lens L can be irradiated with the line light.

[0054] In the state ST1, when the lens L is imaged by the imaging unit 30, the position of the line light source 22 is determined so that the line light source 22 does not appear in the irradiation range AR1 in the captured image. Such a position of the line light source 22 varies depending on the shape of the lens L to be inspected and is determined according to the shape of the object to be inspected.

[0055] Similarly, in the state ST2, when the lens L is imaged by the imaging unit 30, the position of the line light source 22 is determined so that the line light source 22 does not appear in the irradiation range AR2 in the captured image. Such a position of the line light source 22 varies depending on the shape of the lens L to be inspected and is determined according to the shape of the object to be inspected.

[0056] Depending on the structure of the lens L, in either state ST1 or state ST2, there may be a blind spot area that cannot be imaged by the imaging unit 30 near the periphery of the inspection target area of the lens L, or there may be an area where the luminance does not become sufficiently low near the periphery of the inspection target area of the lens L in the captured image of the lens L. In such a case, the position of the imaging unit 30 and the position of the line light source 22 are changed so that the periphery of the inspection target area of the lens L can be imaged by the imaging unit 30 and the luminance of the captured image of this periphery becomes sufficiently low.

[0057] The overall control unit 40, for example, as shown in state ST3 of FIG. 2, tilts the optical axis of the imaging unit 30 with respect to the optical axis K of the lens L, and controls the position of the imaging unit 30 and the position of the line light source 22 so that the line light from the line light source 22 is irradiated onto a region (third region) different from that in state ST2 at one end of the lens L in the direction X. The overall control unit 40 rotates the mounting unit 10 once in this state ST3, and images the lens L when the mounting unit 10 is at each rotation position (rotation position that is N times 12 degrees).

[0058] In this case, the overall control unit 40 detects defects in the first evaluation item from each of the 87 captured images obtained by 29 captures in state ST1, 29 captures in state ST2, and 29 captures in state ST3, and ranks the lens L based on the detection results.

[0059] Note that, in any of state ST1, state ST2, and state ST3, there may be a case where there is a lens with a blind spot area that cannot be imaged by the imaging unit 30. In this case, after inverting the front and back of the lens on the mounting unit 10, the position of the imaging unit 30 and the position of the line light source 22 may be controlled to perform additional imaging so that the defects existing in this blind spot area can be imaged.

[0060] The state ST1 in FIG. 2 indicates a state where the position of the imaging unit 30 is the first imaging position and the position of the line light source 22 is the second irradiation position. The state ST2 in FIG. 2 indicates a state where the position of the imaging unit 30 is the first imaging position and the position of the line light source 22 is the first irradiation position. The state ST3 in FIG. 2 indicates a state where the position of the imaging unit 30 is the second imaging position.

[0061] (First reflected light inspection process) The first reflected light inspection process includes position control for controlling the positions of the flat light source 21 and the imaging unit 30 to positions determined according to the lens information of the lens L, actuating the flat light source 21 and the imaging unit 30 whose positions are determined by this position control, and imaging control for imaging the lens L irradiated with flat light a plurality of times by the imaging unit 30 while rotating the placement unit 10, and evaluation processing for evaluating the second evaluation item of the lens L based on a plurality of captured images obtained by this imaging control.

[0062] The second evaluation item is a defect observable by specularly reflected light, such as coating peeling (peeling of the antireflection coating provided on the outer surface), burning (color unevenness of the coating, or a portion with an appearance different from the normal portion), etc., which are widely known as lens defects. Coating peeling and burning are major defects of the lens, but other evaluation items may also be used.

[0063] The evaluation of the second evaluation item of the lens L means, for example, ranking the lens L based on the feature amount (size) of the coating peeling region detected from the captured image, and ranking the lens L based on the feature amount (size, color information (RGB, HSV), etc.) of the burning region detected from the captured image. The size can be calculated, for example, by (long side + short side) / 2 of the smallest rectangle surrounding the defect. Also, as the size, the area of the smallest rectangle surrounding the defect may be calculated. Also, RGB is an abbreviation for Red, Green, Blue. HSV is an abbreviation for Hue, Saturation, Value.

[0064] Coating peeling and burning are visually recognized by irradiating light from one side in the optical axis direction of the lens L and observing the reflected light of this light from one side in the optical axis direction of the lens L. In the captured image of the lens L, the area where the flat light source 21 is reflected will have no luminance unevenness if there is no coating peeling in that area. If there is coating peeling in this area, an increase in luminance will occur at the site where it exists. Therefore, the presence or absence of coating peeling can be determined by determining the presence or absence of an area where the luminance is equal to or higher than the threshold value in the area including the flat light source 21 (the area where the flat light source 21 is reflected) in the captured image.

[0065] Also, in the captured image of the lens L, the area where the flat light source 21 is reflected will have no luminance unevenness or color unevenness if there is no burning in that area. If there is burning in this area, luminance unevenness or color unevenness will occur at the site where it exists. Therefore, the presence or absence of burning can be determined by determining the presence or absence of an area where the luminance is higher than the periphery or the color tone is different from the periphery in the area including the flat light source 21 in the captured image. In the first reflected light inspection process, coating peeling and burning are detected based on such an idea, and an evaluation for the second evaluation item is performed based on the feature amounts of each defect.

[0066] FIG. 4 is a schematic diagram showing an example of the positional relationship among the imaging unit 30, the placement unit 10, and the flat light source 21 during the first reflected light inspection process.

[0067] In the first reflected light inspection process, the overall control unit 40 performs the above-described position control so that the state ST4 in FIG. 4 is achieved, rotates the placement unit 10 once in this state ST4, and captures an image of the lens L when the placement unit 10 is at each rotation position (rotation positions that are N times 12 degrees).

[0068] Furthermore, the overall control unit 40 performs the above-described position control so that the state ST5 in FIG. 4 is achieved, rotates the placement unit 10 once in this state ST5, and captures an image of the lens L when the placement unit 10 is at each rotation position (rotation positions that are N times 12 degrees).

[0069] The overall control unit 40 detects defects in the second evaluation item from each of the 58 captured images obtained by 29 times of imaging in the state ST4 and 29 times of imaging in the state ST5, and ranks the lens L based on the detection results.

[0070] The state ST4 shown in FIG. 4 is a state in which the optical axis of the imaging unit 30 is inclined with respect to the optical axis K of the lens L, and the direction in which the perpendicular to the light emitting surface of the flat light source 21 extends is inclined with respect to the optical axis K.

[0071] FIG. 5 shows, in the state ST4, the light reflection region of the lens L where the reflected light of the flat light irradiated from the flat light source 21 is incident on the imaging unit 30 in a sufficient amount, indicated by a frame AR3. In the state ST4, there is a light reflection region in which a sufficient amount of flat light is reflected toward the imaging unit 30 at the central portion of the lens L in the directions X and Y. By rotating the placement unit 10 once in the state ST4, it becomes possible to image a sufficient amount of reflected light from a portion excluding the outer peripheral portion in the radial direction of the inspection target region of the lens L with the imaging unit 30.

[0072] The state ST5 shown in FIG. 4 is a state in which the positions of the imaging unit 30 and the flat light source 21 are changed with respect to the state ST4. FIG. 5 shows, in the state ST5, the light reflection region of the lens L where the reflected light of the flat light irradiated from the flat light source 21 is incident on the imaging unit 30 in a sufficient amount, indicated by a frame AR4. In the state ST5, there is a light reflection region in which a sufficient amount of flat light is reflected toward the imaging unit 30 at one end portion of the lens L in the direction X. By rotating the placement unit 10 once in the state ST5, it becomes possible to image a sufficient amount of reflected light from the outer peripheral portion in the radial direction of the inspection target region of the lens L with the imaging unit 30.

[0073] Thus, in the first reflected light inspection process, the positions of the imaging unit 30 and the flat light source 21 are determined so that a sufficient amount of reflected light is incident on the imaging unit 30 from the entire inspection target region of the lens L. Such combinations of the position of the imaging unit 30 and the position of the flat light source 21 vary depending on the shape of the lens L to be inspected and are determined according to the shape of the subject.

[0074] For example, when the lens L is a concave lens, imaging of the lens L is performed in the states ST6 and ST7 of FIG. 6. The frames AR5 and AR6 shown in FIG. 6 indicate the light reflection regions of the lens L where the reflected light of the flat light irradiated from the flat light source 21 is incident on the imaging unit 30 in a sufficient amount.

[0075] Note that depending on the structure of the lens L, it may not be possible to make a sufficient amount of reflected light from the entire inspection target region of the lens L incident on the imaging unit 30 only by imaging from one surface side in the optical axis direction. In such a case, the imaging may be performed by controlling the positions of the imaging unit 30 and the flat light source 21 after inverting the front and back of the lens L in the placement unit 10.

[0076] (Second reflected light inspection process) The second reflected light inspection process includes position control for controlling the positions of the spot light source 23 and the imaging unit 30 to positions determined according to the lens information of the lens L, operating the spot light source 23 and the imaging unit 30 whose positions are determined by this position control, and imaging the lens L irradiated with the spot light a plurality of times by the imaging unit 30 while rotating the placement unit 10, and evaluation processing for evaluating the third evaluation item of the lens L based on a plurality of imaging images obtained by this imaging control.

[0077] The third evaluation item is ink defect that can occur only in lenses with ink-coated parts. Ink defect refers to a state where a part of the ink-coated part is thin or peeled off.

[0078] The evaluation of the third evaluation item of the lens L means ranking the lens L based on the feature amount (length or area) of the ink defect region detected from the imaging image.

[0079] The ink defect is visually recognized by irradiating light onto the ink-applied portion of the lens L from one side in the optical axis direction of the lens L and observing the reflected light of this light from one side in the optical axis direction of the lens L. In the captured image of the lens L, the ink-applied portion would be in a low-luminance state if there were no ink defects. On the other hand, if there is an ink defect, the luminance becomes high at the location of the defect. Therefore, by searching for a high-luminance region in the region including the ink-applied portion of the captured image, the presence or absence of an ink defect can be determined. In the second reflected light inspection process, based on such an idea, an ink defect is detected, and based on the detection result, an evaluation for the third evaluation item is performed.

[0080] FIG. 7 is a schematic diagram showing an example of the positional relationship among the imaging unit 30, the placement unit 10, and the spot light source 23 during the second reflected light inspection process. The lens L shown in FIG. 7 is provided with an ink-applied portion BL.

[0081] In the second reflected light inspection process, the overall control unit 40 performs the above-described position control so that the state ST8 in FIG. 7 is achieved, and in this state ST8, the placement unit 10 is rotated once, and the lens L is imaged when the placement unit 10 is at each rotation position (rotation positions that are N times 12 degrees). By rotating the placement unit 10 once in the state ST8, the reflected light from the entire ink-applied portion BL of the lens L can be imaged by the imaging unit 30. Note that, as described above, 12 degrees is an example, and the imaging interval (angle) and the number of imaging times can be arbitrarily set.

[0082] The overall control unit 40 detects defects in the third evaluation item from each ink-applied portion of the 29 captured images obtained by imaging 29 times in the state ST8, and ranks the lens L based on the detection result.

[0083] Note that there may be cases where the reflected light of the spot light cannot be imaged from the entire ink-applied portion BL of the lens L only in the state ST8, or where a partial region of the ink-applied portion BL shines overall in the state ST8. In this case, imaging is performed under another condition in which the positions of the imaging unit 30 and the spot light source 23 are changed, for example, as in the state ST9.

[0084] In this way, by imaging the lens L in a plurality of states, it becomes possible to detect without omission the ink defect region (the region where the luminance increases due to the irradiation of the spot light) existing in the ink smeared portion BL. In this case, the overall control unit 40 detects defects from each ink smeared portion BL of the 58 captured images obtained by the 29 times of imaging in the state ST8 and the 29 times of imaging in the state ST9, and ranks the lens L based on the detection results.

[0085] In this way, in the second reflected light inspection process, the positions of the imaging unit 30 and the spot light source 23 are determined so that the reflected light from the entire ink smeared portion BL of the lens L is incident on the imaging unit 30. Such a combination of the position of the imaging unit 30 and the position of the spot light source 23 varies depending on the shape of the lens L to be inspected and is determined according to the shape of the object to be inspected.

[0086] FIG. 8 is a flowchart for explaining the operation during the transmitted light inspection process of the appearance inspection apparatus 100. Hereinafter, the case of performing the inspection under two conditions of the state ST1 and the state ST2 shown in FIG. 2 will be described as an example.

[0087] The overall control unit 40 acquires the lens information of the lens L, and determines the state ST1 and the state ST2 based on this lens information. Then, the overall control unit 40 first controls the position of the imaging unit 30 and the position of the line light source 22 so as to be in the state ST1 (step S1).

[0088] Next, the overall control unit 40 rotationally drives the placement unit 10, and each time the rotation angle of the placement unit 10 increases by 12 degrees, causes the imaging unit 30 to image the lens L placed on the placement unit 10, acquires the captured image of the lens L from the imaging unit 30, and stores it (step S2).

[0089] Next, the overall control unit 40 controls the position of the imaging unit 30 and the position of the line light source 22 so as to be in the state ST2 (step S3).

[0090] Next, the overall control unit 40 rotationally drives the mounting unit 10, and every time the rotation angle of the mounting unit 10 increases by 12 degrees, causes the imaging unit 30 to image the lens L mounted on the mounting unit 10, acquires the captured image of the lens L from the imaging unit 30, and stores it (step S4).

[0091] Next, based on a total of 58 captured images obtained by combining the 29 captured images saved in step S2 and the 29 captured images saved in step S4, the overall control unit 40 evaluates the lens L for each of the four first evaluation items of scratches, foreign matter, cloudiness, and dirt (step S5).

[0092] FIG. 9 and FIG. 10 are flowcharts for explaining the details of step S5 in FIG. 8.

[0093] The overall control unit 40 sets the reference number "N" to 1 (step S11), and performs a defect detection process on the first predetermined region in the "N" - th captured image among the 29 captured images saved in step S2 (step S12).

[0094] The first predetermined region is a region where line light does not shine in the captured image and the luminance is sufficiently low, and is determined in advance according to the lens information. The first predetermined region may also be a region designated by the user.

[0095] The defect detection process is a process of detecting a region with a luminance equal to or higher than a threshold value as a defect by performing binarization or differentiation processing on the pixel values of the first predetermined region. The defect detection process algorithms are prepared for each type of defect of scratches, foreign matter, cloudiness, and dirt. The overall control unit 40 individually executes four types of defect detection processes on one captured image.

[0096] Next, the overall control unit 40 calculates the feature amounts of the defects for each type of defect detected in the defect detection process in step S12, and stores them (step S13).

[0097] Hereinafter, the feature amount of the scratch defect detected from the N-th captured image is referred to as a scratch feature amount Pk(N). The feature amount of the bump defect detected from the N-th captured image is referred to as a bump feature amount Pb(N). The feature amount of the clouding defect detected from the N-th captured image is referred to as a clouding feature amount Pc(N). The feature amount of the stain defect detected from the N-th captured image is referred to as a stain feature amount Py(N). The scratch feature amount Pk(N), the bump feature amount Pb(N), the clouding feature amount Pc(N), and the stain feature amount Py(N) are collectively referred to as a feature amount P(N).

[0098] Next, the overall control unit 40 holds the maximum value among the feature amounts P(N) as evaluation data (step S14).

[0099] Specifically, the overall control unit 40 holds the maximum value among the scratch feature amounts Pk(N) as scratch evaluation data for evaluating scratch defects. The overall control unit 40 holds the maximum value among the bump feature amounts Pb(N) as bump evaluation data for evaluating bump defects. The overall control unit 40 holds the maximum value among the clouding feature amounts Pc(N) as clouding evaluation data for evaluating clouding defects. The overall control unit 40 holds the maximum value among the stain feature amounts Py(N) as stain evaluation data for evaluating stain defects. For defect types in which no defects are detected, the overall control unit 40 holds, for example, the minimum value that can be considered as a feature amount as evaluation data.

[0100] Next, the overall control unit 40 increments the reference number “N” by one (step S15), and performs a defect detection process on the first predetermined region in the “N”-th captured image among the 29 captured images saved in step S2 (step S16).

[0101] Next, the overall control unit 40 calculates the feature amount P(N) of the defect for each defect type detected in the defect detection process in step S16, and saves this (step S17).

[0102] Next, the overall control unit 40 determines whether the maximum value among the feature amounts P(N) calculated in step S17 is greater than the evaluation data for each of the defect types of scratches, foreign objects, cloudiness, and dirt (step S18).

[0103] If there is a defect type in which the maximum value among the feature amounts P(N) calculated in step S17 is greater than the evaluation data, the overall control unit 40 updates the evaluation data for that defect type with this maximum value (step S19).

[0104] Specifically, when the maximum value among the scratch feature amounts Pk(N) is greater than the scratch evaluation data, the overall control unit 40 holds this maximum value as the latest scratch evaluation data. When the maximum value among the scratch feature amounts Pk(N) is less than or equal to the scratch evaluation data, the overall control unit 40 does not update the scratch evaluation data.

[0105] When the maximum value among the foreign object feature amounts Pb(N) is greater than the foreign object evaluation data, the overall control unit 40 holds this maximum value as the latest foreign object evaluation data. When the maximum value among the foreign object feature amounts Pb(N) is less than or equal to the foreign object evaluation data, the overall control unit 40 does not update the foreign object evaluation data.

[0106] When the maximum value among the cloudiness feature amounts Pc(N) is greater than the cloudiness evaluation data, the overall control unit 40 holds this maximum value as the latest cloudiness evaluation data. When the maximum value among the cloudiness feature amounts Pc(N) is less than or equal to the cloudiness evaluation data, the overall control unit 40 does not update the cloudiness evaluation data.

[0107] When the maximum value among the dirt feature amounts Py(N) is greater than the dirt evaluation data, the overall control unit 40 holds this maximum value as the latest dirt evaluation data. When the maximum value among the dirt feature amounts Py(N) is less than or equal to the dirt evaluation data, the overall control unit 40 does not update the dirt evaluation data.

[0108] After step S19, if the reference number "N" is less than 29 (step S20: NO), the overall control unit 40 returns the process to step S15, and if the reference number "N" is 29 (step S20: YES), the process of step S21 is performed.

[0109] In step S21, the overall control unit 40 sets the reference number "M" to 1. Next, the overall control unit 40 performs a defect detection process on the second predetermined area in the "M" -th captured image among the 29 captured images saved in step S4 (step S22).

[0110] The second predetermined area is, similar to the first predetermined area, an area where line light is not reflected in the captured image and the luminance is sufficiently low, and is determined in advance according to the lens information. The second predetermined area may also be an area designated by the user.

[0111] Next, the overall control unit 40 calculates the feature amount of the defect for each defect type detected in the defect detection process of step S22 and saves it (step S23).

[0112] Hereinafter, the feature amount of the scratch defect detected from the "M" -th captured image is denoted as scratch feature amount Pk(M). The feature amount of the stain defect detected from the "M" -th captured image is denoted as stain feature amount Pb(M). The feature amount of the haze defect detected from the "M" -th captured image is denoted as haze feature amount Pc(M). The feature amount of the dirt defect detected from the "M" -th captured image is denoted as dirt feature amount Py(M). The scratch feature amount Pk(M), the stain feature amount Pb(M), the haze feature amount Pc(M), and the dirt feature amount Py(M) are collectively denoted as feature amount P(M).

[0113] Next, the overall control unit 40 determines for each defect type of scratch, stain, haze, and dirt whether the maximum value among the feature amounts P(M) calculated in step S23 is greater than the evaluation data (step S24).

[0114] If there is a defect type for which the maximum value among the feature amounts P(M) calculated in step S23 is greater than the evaluation data, the overall control unit 40 updates the evaluation data of that defect type with this maximum value (step S25).

[0115] Specifically, when the maximum value among the scratch feature amounts Pk(M) is greater than the scratch evaluation data, the overall control unit 40 holds this maximum value as the latest scratch evaluation data. When the maximum value among the scratch feature amounts Pk(M) is less than or equal to the scratch evaluation data, the overall control unit 40 does not update the scratch evaluation data.

[0116] When the maximum value among the foreign matter feature amounts Pb(M) is greater than the foreign matter evaluation data, the overall control unit 40 holds this maximum value as the latest foreign matter evaluation data. When the maximum value among the foreign matter feature amounts Pb(M) is less than or equal to the foreign matter evaluation data, the overall control unit 40 does not update the foreign matter evaluation data.

[0117] When the maximum value among the cloudiness feature amounts Pc(M) is greater than the cloudiness evaluation data, the overall control unit 40 holds this maximum value as the latest cloudiness evaluation data. When the maximum value among the cloudiness feature amounts Pc(M) is less than or equal to the cloudiness evaluation data, the overall control unit 40 does not update the cloudiness evaluation data.

[0118] When the maximum value among the stain feature amounts Py(M) is greater than the stain evaluation data, the overall control unit 40 holds this maximum value as the latest stain evaluation data. When the maximum value among the stain feature amounts Py(M) is less than or equal to the stain evaluation data, the overall control unit 40 does not update the stain evaluation data.

[0119] After step S25, when the reference number "M" is less than 29 (step S26: NO), the overall control unit 40 increments the reference number "M" by 1 (step S27), and then returns the process to step S22. When the reference number "M" is 29 (step S26: YES), the overall control unit 40 performs the process of step S28.

[0120] In step S28, the overall control unit 40 classifies the lens L by comparing the evaluation data for each defect type with a threshold value and stores the result. Specifically, the overall control unit 40 stores the evaluation rank of the lens L for scratch defects, the evaluation rank of the lens L for foreign matter defects, the evaluation rank of the lens L for haze defects, and the evaluation rank of the lens L for stain defects, respectively.

[0121] After the operation of FIG. 8, the overall control unit 40 performs the operation shown in FIG. 11. FIG. 11 is a flowchart for explaining the operation during the first reflected light inspection process of the appearance inspection apparatus 100. Hereinafter, the case where the inspection is performed under two conditions, the state ST4 and the state ST5, shown in FIG. 4 will be described as an example.

[0122] The overall control unit 40 acquires the lens information of the lens L and determines the state ST4 and the state ST5 based on this lens information. Then, the overall control unit 40 first controls the position of the imaging unit 30 and the position of the flat light source 21 so as to be in the state ST4 (step S6).

[0123] Next, the overall control unit 40 rotationally drives the mounting unit 10, and every time the rotation angle of the mounting unit 10 increases by 12 degrees, causes the imaging unit 30 to image the lens L mounted on the mounting unit 10, acquires and stores the captured image of the lens L from the imaging unit 30 (step S7).

[0124] Next, the overall control unit 40 controls the position of the imaging unit 30 and the position of the flat light source 21 so as to be in the state ST5 (step S8).

[0125] Next, the overall control unit 40 rotationally drives the mounting unit 10, and every time the rotation angle of the mounting unit 10 increases by 12 degrees, causes the imaging unit 30 to image the lens L mounted on the mounting unit 10, acquires and stores the captured image of the lens L from the imaging unit 30 (step S9).

[0126] Next, the overall control unit 40 evaluates the lens L for each of the two second evaluation items of coating peeling and burning, based on a total of 58 captured images obtained by combining the 29 captured images saved in step S7 and the 29 captured images saved in step S9 (step S10).

[0127] The process of step S10 is the same as the content shown in FIGS. 9 and 10. That is, the overall control unit 40 holds, as coating peeling evaluation data, the maximum value among the feature amounts of coating peeling defects extracted from each of the 59 captured images, and holds, as burning evaluation data, the maximum value among the feature amounts of burning defects extracted from each of the 59 captured images.

[0128] Then, the overall control unit 40 compares this coating peeling evaluation data with a threshold value to determine the evaluation rank of the lens L for coating peeling defects, compares this burning evaluation data with a threshold value to determine the evaluation rank of the lens L for burning defects, and saves the determination result.

[0129] After the operations of FIGS. 8 and 11 are completed, the overall control unit 40 determines, for example, the defect type with the worst evaluation rank, and outputs the evaluation rank of that defect type as the final result.

[0130] Note that depending on the structure of the lens L, the overall control unit 40 further executes a second reflected light inspection process and also evaluates ink defects.

[0131] According to the above appearance inspection apparatus 100, by transmitting line light through the lens L and observing the area of the lens L where the line light source 22 does not shine, defects (scratches, bumps, fogginess, and stains) that can be visually recognized can be detected with high precision by transmission light inspection processing. Further, according to the appearance inspection apparatus 100, by reflecting flat light on the lens L and observing the area of the lens L where the flat light shines, defects (coating peeling and burning) that can be visually recognized can be detected with high precision by first reflected light inspection processing. Further, according to the appearance inspection apparatus 100, by observing the reflected light when spot light is irradiated on the blackened portion of the lens L, defects (blackening defects) that can be visually recognized can be detected with high precision by second reflected light inspection processing.

[0132] Thus, according to the appearance inspection apparatus 100, by imaging the lens L under a plurality of conditions (for example, state ST1, state ST2, state ST4, and state ST5) in which the relative positions of the mounting unit 10, the illumination unit 20, and the imaging unit 30 and the shape of the light irradiated from the illumination unit 20 are different, various types of defects that can occur in the lens L and that cannot be detected by imaging using only illumination light of a single shape or imaging only the reflected light from the object can be detected with high precision.

[0133] Further, in the appearance inspection apparatus 100, when evaluating the same defect type (for example, scratch defect), although the positions of the illumination unit 20 and the imaging unit 30 are the same, scratch defects are detected from each of 29 captured images in which the rotational positions of the mounting unit 10 are different. Then, based on the maximum value among the feature amounts of all the detected scratch defects, an evaluation of the lens L for the scratch defects is performed.

[0134] The visible appearance of the scratch defect existing in the lens L from the imaging unit 30 may vary depending on the rotational position of the placement unit 10. This is because the way the line light is irradiated onto the scratch defect varies depending on the rotational position. According to the appearance inspection apparatus 100, the lens L is evaluated based on the maximum value of the feature amount of the scratch defect detected from each of the 29 captured images. For this reason, even if there is a large scratch, it is possible to prevent the feature amount of the scratch from being judged as a small value. As a result, the evaluation of the lens L can be performed with high accuracy.

[0135] Also, in the appearance inspection apparatus 100, in order to detect defects of the same type, imaging is performed under two conditions (state ST1 and state ST2, or state ST4 and state ST5) with different combinations of the position of the imaging unit 30 and the position of the illumination unit 20. For this reason, defects that cannot be detected by only one of the two conditions depending on the way the light hits can be detected by the other condition of the two conditions. Therefore, the detection accuracy of defects can be improved.

[0136] (Modification example) Hereinafter, a modification example of the appearance inspection apparatus 100 will be described. The object to be inspected by the appearance inspection apparatus 100 is not limited to the lens L. As long as the object has light transmissibility, defects of this object can be detected by placing this object on the placement unit 10. In this case, the optical axis K of the lens L described above may be reinterpreted as the central axis of this object.

[0137] In the appearance inspection apparatus 100, the spot light source 23 does not have to be fixed to the imaging unit 30. In this case, a mechanism for moving the spot light source 23 in the directions X and Z and rotating it around an axis extending in the direction Y is separately provided. Note that by adopting the configuration shown in FIG. 1 in which the spot light source 23 is fixed to the imaging unit 30, the mechanism for moving the spot light source 23 can be omitted, and miniaturization and cost reduction of the apparatus can be achieved.

[0138] In the appearance inspection apparatus 100, the spot light source 23 may be replaced with a surface light source that irradiates planar light. For ink defects, it is possible to detect them by irradiating light onto the ink-coated portion of the lens L and imaging the reflected light of the light. Therefore, a surface light source can also be used instead of the spot light source 23. In this case, during the second reflected light inspection process, the flat light source 21 may be moved to the position of the spot light source 23. By doing so, the number of light sources included in the illumination unit 20 can be reduced to two, enabling miniaturization and cost reduction of the apparatus.

[0139] In the appearance inspection apparatus 100, by making the imaging unit 30, the flat light source 21, and the line light source 22 each movable, switching between the states ST1, ST2, and ST3 and switching between the states ST4 and ST5 are enabled. As a modification of this, a plurality of the imaging unit 30, the flat light source 21, and the line light source 22 are fixedly arranged, and one of the plurality of imaging units 30 is selected and operated, one of the plurality of line light sources 22 is selected and operated, and one of the plurality of flat light sources 21 is selected and operated so as to be in any one of the states ST1, ST2, ST3, ST4, and ST5. Also, as another modification, in addition to or instead of moving the imaging unit 30, the flat light source 21, and the line light source 22, the placement unit 10 may be moved or tilted to enable switching between the states ST1, ST2, and ST3 and switching between the states ST4 and ST5. That is, any configuration may be moved as long as the relative positions of the placement unit 10 (lens L), the illumination unit 20, and the imaging unit 30 can be changed. Also, in the appearance inspection apparatus 100, the case where the placement unit 10 is used as an example of the holding unit has been described, but the holding unit may have another configuration as long as the above inspection can be performed without damaging the lens L. For example, the holding unit may be configured to sandwich the lens.

[0140] As described above, at least the following matters are described in this specification. Although the corresponding components, etc. in the above-described embodiments are shown in parentheses, the present invention is not limited thereto.

[0141] (1) A holding unit for holding a subject, An illumination unit capable of irradiating the holding unit with illumination light of a plurality of shapes, An imaging unit for imaging the holding unit, A driving unit for changing the relative positions of the holding unit, the illumination unit, and the imaging unit, A processor that performs control to change the relative position and the shape of the illumination light and cause the imaging unit to image the subject a plurality of times, and includes: The processor is an appearance inspection device that causes the imaging unit to image the subject including reflected light reflected by the subject from the illumination light and the subject including transmitted light transmitted through the subject from the illumination light.

[0142] (2) The appearance inspection device according to (1), wherein The driving unit includes a rotation mechanism that rotates the holding unit to a plurality of rotational positions.

[0143] (3) The appearance inspection device according to (1) or (2), wherein The driving unit includes a driving mechanism that moves the illumination unit and the imaging unit relative to the holding unit.

[0144] (4) The appearance inspection device according to any one of (1) to (3), wherein When the side on which the imaging unit is disposed with respect to the holding unit is a first side and the side opposite to the first side is a second side, The processor Performs control to cause the imaging unit to image the subject in a state where illumination light of a first shape is irradiated from the second side to the holding unit, and Performs control to cause the imaging unit to image the subject in a state where illumination light of a second shape is irradiated from the first side to the holding unit.

[0145] (5) The appearance inspection device according to any one of (1) to (3), wherein The light of the plurality of shapes includes linear light, When the side where the imaging unit is arranged with respect to the holding unit is defined as the first side and the side opposite to the first side is defined as the second side, the linear light is irradiated from the second side, the transmitted light is the linear light that has passed through the subject, and it is an appearance inspection device.

[0146] (6) The appearance inspection device according to (5), When the processor irradiates the linear light, the processor controls the position of the illumination unit to a first irradiation position where the linear light is irradiated to a first region at an end of the subject and a second irradiation position where the linear light is irradiated to a second region away from the end of the subject. It is an appearance inspection device.

[0147] (7) The appearance inspection device according to (6), When the processor irradiates the linear light, the processor controls the position of the imaging unit to at least the first imaging position among a first imaging position where the optical axis of the imaging unit is parallel to the central axis of the subject and a second imaging position where the optical axis is inclined with respect to the central axis. It is an appearance inspection device.

[0148] (8) The appearance inspection device according to (7), When the imaging unit is at the first imaging position, the processor irradiates the linear light from the first irradiation position to image the subject with the imaging unit. When the imaging unit is at the first imaging position, the processor irradiates the linear light from the second irradiation position to image the subject with the imaging unit. When the imaging unit is at the second imaging position, the processor irradiates the linear light to a third region different from the first region at the end of the subject to image the subject with the imaging unit. It is an appearance inspection device.

[0149] (9) The appearance inspection device according to any one of (1) to (8), the light of the plurality of shapes includes planar light, An appearance inspection apparatus in which the reflected light includes the planar light reflected by the subject.

[0150] (10) The appearance inspection apparatus according to (9), wherein the processor changes the combination of the planar light and the relative position to two or more types in which the positions of the illumination unit and the imaging unit are different, and images the subject including the reflected light.

[0151] (11) The appearance inspection apparatus according to any one of (1) to (10), wherein the subject is a lens, and the processor acquires information regarding the shape of the lens and changes the positions of the illumination unit and the imaging unit according to the shape of the lens.

[0152] (12) The appearance inspection apparatus according to any one of (1) to (11), wherein the plurality of shaped lights include planar light, linear light, and dot light, and the processor controls the positions of the illumination unit when irradiating the planar light, the positions of the illumination unit when irradiating the linear light, and the positions of the illumination unit when irradiating the dot light to be different positions.

[0153] (13) The appearance inspection apparatus according to any one of (1) to (12), wherein the illumination unit includes a surface light source that irradiates planar light, a linear light source that irradiates linear light, and a point light source that irradiates dot light, and the point light source moves in conjunction with the imaging unit, and the surface light source and the linear light source move independently.

[0154] (14) The appearance inspection apparatus according to any one of (1) to (12), wherein the illumination unit includes a surface light source that irradiates planar light, a linear light source that irradiates linear light, and a point light source that irradiates dot light, An appearance inspection apparatus in which the surface light source, the line light source, and the point light source move independently.

[0155] (15) The appearance inspection apparatus according to any one of (1) to (14), wherein the driving unit includes a rotation mechanism that rotates the holding unit, and the processor is an appearance inspection apparatus that captures the subject a plurality of times while rotating the holding unit in a state where the combination of the shape of the illumination light, the position of the illumination unit, and the position of the imaging unit is determined.

[0156] (16) The appearance inspection apparatus according to (15), wherein the processor detects a specific part (defect region) from each of a plurality of captured images acquired from the imaging unit for each combination in which the shape of the illumination light is common, and evaluates the subject based on the feature amount of the specific part having the maximum feature amount among the detected specific parts.

[0157] (17) A holding unit for holding a subject, An illumination unit capable of irradiating the holding unit with illumination light of a plurality of shapes, An imaging unit for imaging the holding unit, A driving unit for changing the relative positions of the holding unit, the illumination unit, and the imaging unit, and a processor for controlling the relative position and the shape of the illumination light to capture the subject a plurality of times by the imaging unit, wherein the processor is an appearance inspection apparatus that changes the positions of both the illumination unit and the imaging unit to image the subject by the imaging unit.

[0158] (18) The appearance inspection apparatus according to (17), When the side where the imaging unit is arranged with respect to the holding unit is the first side and the side opposite to the first side is the second side, the processor controls the imaging unit to image the subject with the illumination light of the first shape irradiated from the second side to the holding unit, and controls the imaging unit to image the subject with the illumination light of the second shape irradiated from the first side to the holding unit. An appearance inspection apparatus that performs the above.

[0159] (19) An appearance inspection method for inspecting the appearance of a subject using a holding unit for holding the subject, an illumination unit capable of irradiating the holding unit with illumination light of a plurality of shapes, an imaging unit for imaging the holding unit, and a driving unit for changing the relative positions of the holding unit, the illumination unit, and the imaging unit, Comprising a control step of controlling to change the relative position and the shape of the illumination light and image the subject a plurality of times by the imaging unit. In the control step, an appearance inspection method in which the imaging unit images the subject including reflected light reflected by the subject from the illumination light and the subject including transmitted light transmitted through the subject by the illumination light.

[0160] (20) An appearance inspection method for inspecting the appearance of a subject using a holding unit for holding the subject, an illumination unit capable of irradiating the holding unit with illumination light of a plurality of shapes, an imaging unit for imaging the holding unit, and a driving unit for changing the relative positions of the holding unit, the illumination unit, and the imaging unit, Comprising a control step of controlling to change the relative position and the shape of the illumination light and image the subject a plurality of times by the imaging unit. In the control step, an appearance inspection method in which the positions of both the illumination unit and the imaging unit are changed to image the subject by the imaging unit.

[0161] (21) An appearance inspection program for inspecting the appearance of a subject, using a holding unit for holding the subject, an illumination unit capable of irradiating the holding unit with illumination light of a plurality of shapes, an imaging unit for imaging the holding unit, and a driving unit for changing the relative positions of the holding unit, the illumination unit, and the imaging unit, wherein: a control step of changing the relative position and the shape of the illumination light to cause the imaging unit to image the subject a plurality of times is executed by a computer; in the control step, the imaging unit images the subject including reflected light reflected by the subject from the illumination light and the subject including transmitted light transmitted through the subject from the illumination light. An appearance inspection program.

[0162] (22) An appearance inspection program for inspecting the appearance of a subject, using a holding unit for holding the subject, an illumination unit capable of irradiating the holding unit with illumination light of a plurality of shapes, an imaging unit for imaging the holding unit, and a driving unit for changing the relative positions of the holding unit, the illumination unit, and the imaging unit, wherein: a control step of changing the relative position and the shape of the illumination light to cause the imaging unit to image the subject a plurality of times is executed by a computer; in the control step, the positions of both the illumination unit and the imaging unit are changed to cause the imaging unit to image the subject. An appearance inspection program.

[0163] As described above, various embodiments have been described with reference to the drawings, but it goes without saying that the present invention is not limited to such examples. It is obvious that those skilled in the art can conceive of various modification examples or correction examples within the scope described in the claims, and it is naturally understood that they also belong to the technical scope of the present invention. Also, within the scope not departing from the gist of the invention, the constituent elements in the above embodiments may be arbitrarily combined.

[0164] This application is based on a Japanese patent application filed on November 27, 2020 (Japanese Patent Application No. 2020-197622), the content of which is incorporated herein by reference.

Explanation of Reference Numerals

[0165] AR1, AR2 Irradiation range AR3, AR4, AR5, AR6 Frame 10A Rotating mechanism 10 Mounting portion 11 Base 20 Lighting unit 21 Flat light source 21A Flat light source drive mechanism 22 Line light source 22A Line light source drive mechanism 23 Spot light source 30 Imaging unit 30A Imaging unit drive mechanism 40 Overall control unit 41 Position control unit 42 Lighting control unit 100 Appearance inspection device L Lens Ax1, Ax2, Ax3 Axis K Optical axis BL Ink coating portion

Claims

1. A holding part that is rotatably supported on the inner wall of the through-hole of the base and holds the subject, a rotation mechanism that rotates the holding part around a rotation axis extending in the direction of the through-hole, an imaging unit that is disposed on a first side, which is one side in the direction of the through-hole with respect to the holding part, and images the subject held by the holding part, an imaging unit drive mechanism that changes the position of the imaging unit with respect to the base and the imaging direction, a flat light source that is disposed on the first side and can irradiate the subject held by the holding part with planar light, a flat light source drive mechanism that changes the position of the flat light source with respect to the base and the irradiation direction with respect to the subject held by the holding part, a line light source that is disposed on a second side, which is the side opposite to the first side with respect to the holding part, and can irradiate the subject held by the holding part with linear light, a line light source drive mechanism that changes the position of the line light source with respect to the base and the irradiation direction with respect to the subject held by the holding part, a controller that drives the rotation mechanism, the imaging unit drive mechanism, the flat light source drive mechanism, and the line light source drive mechanism, a controller that operates the flat light source and the line light source, and a processor that performs control to operate the imaging unit, The processor drives the rotation mechanism so that when the subject held by the holding part is at a plurality of rotation positions, the imaging unit images the subject including reflected light reflected by the planar light from the flat light source by the subject and the subject including transmitted light transmitted through the subject by the linear light from the line light source. An appearance inspection device.

2. The appearance inspection device according to Claim 1, when irradiating the linear light, the processor drives the line light source drive mechanism to control the position of the line light source to a first irradiation position where the linear light is irradiated to a first region at an end of the subject and a second irradiation position where the linear light is irradiated to a second region away from the end of the subject. An appearance inspection device.

3. The appearance inspection device according to Claim 2, when irradiating the linear light, the processor controls the position of the imaging unit to at least the first imaging position among a first imaging position where the optical axis of the imaging unit is parallel to the central axis of the subject and a second imaging position where the optical axis is inclined with respect to the central axis. An appearance inspection device.

4. The appearance inspection device according to Claim 3, The processor irradiates the linear light from the first irradiation position to image the subject by the imaging unit in a state where the imaging unit is at the first imaging position, irradiates the linear light from the second irradiation position to image the subject by the imaging unit in a state where the imaging unit is at the first imaging position, and irradiates the linear light to a third region different from the first region at the end of the subject in a state where the imaging unit is at the second imaging position to image the subject by the imaging unit. An appearance inspection device.

5. An appearance inspection device according to any one of claims 1 to 4, When the processor irradiates the planar light, the flat light source drive mechanism is driven to control the position of the flat light source to a position where a sufficient amount of planar light is irradiated to the central portion of the subject and a position where a sufficient amount of planar light is irradiated to one end of the subject. An appearance inspection device.

6. An appearance inspection device according to claim 5, When the processor irradiates the planar light, the imaging unit drive mechanism is driven to control the position of the imaging unit to a position where a sufficient amount of reflected light from the subject is incident on the imaging unit. An appearance inspection device.

7. An appearance inspection device according to any one of claims 1 to 6, The processor images the subject including the reflected light of the planar light from the flat light source reflected by the subject and the subject including the transmitted light of the linear light from the line light source transmitted through the subject when the subject held by the holding unit is at a plurality of rotational positions in a state where the position of the flat light source, the position of the line light source, and the position of the imaging device are controlled to specific positions. An appearance inspection device.

8. An appearance inspection device according to claim 7, The processor performs detection of a specific part from each of a plurality of imaging images when the subject is at a plurality of rotational positions, acquired from the imaging unit in a state where the position of the flat light source, the position of the line light source, and the position of the imaging device are controlled to specific positions, and evaluates the subject based on the feature amount of the specific part having the maximum feature amount among the detected specific parts. An appearance inspection device.

9. An appearance inspection device according to any one of claims 1 to 8, The subject is a lens, The processor acquires information regarding the shape of the lens, and an appearance inspection apparatus that changes the position of the flat light source, the position of the line light source, and the position of the imaging unit according to the shape of the lens.

10. An appearance inspection apparatus according to any one of Claims 1 to 9, furthermore, a spot light source disposed on the first side and capable of irradiating the subject held by the holding unit with a point light; a spot light source drive mechanism that changes the position of the flat light source with respect to the base and the irradiation direction with respect to the subject held by the holding unit; The processor drives the rotation mechanism so that when the subject held by the holding unit is located at a plurality of rotation positions, the imaging unit images the subject including the reflected light of the point light from the spot light source reflected by the subject.

11. An appearance inspection apparatus according to Claim 10, wherein the spot light source is fixed to the imaging unit, and the imaging unit drive mechanism is also used as the spot light source drive mechanism.

12. An appearance inspection apparatus according to Claim 10 or 11, The processor controls the position of the spot light source and the position of the imaging device to specific positions, and when the subject held by the holding unit is located at a plurality of rotation positions, the imaging unit images the subject including the reflected light of the point light from the spot light source reflected by the subject.

13. An appearance inspection apparatus according to Claim 12, The processor performs detection of a specific part from each of a plurality of imaging images when the subject is located at a plurality of rotation positions, acquired from the imaging unit in a state where the position of the spot light source and the position of the imaging device are controlled to specific positions, and evaluates the subject based on the feature amount of the specific part having the maximum feature amount among the detected specific parts.

14. A holding part that is rotatably supported on the inner wall of the through hole of the base and holds the subject, a rotation mechanism that rotates the holding part around a rotation axis extending in the direction of the through hole, and a first side that is on one side in the direction of the through hole from the holding part. An imaging unit that images the subject held by the holding unit, an imaging unit drive mechanism that changes the position of the imaging unit with respect to the base and the imaging direction, a flat light source that is disposed on the first side and can irradiate the subject held by the holding unit with planar light, and the flat light source. A flat light source drive mechanism that changes the position of the light source with respect to the base and the irradiation direction with respect to the subject held by the holding unit, and a line that is disposed on the second side opposite to the first side from the holding unit. A line light source that can irradiate the subject held by the holding unit with linear light, and a line light source drive mechanism that changes the position of the line light source with respect to the base and the irradiation direction with respect to the subject held by the holding unit, and an appearance inspection method for inspecting the appearance of the subject using the same, A drive mechanism control step of driving the rotation mechanism, the imaging unit drive mechanism, the flat light source drive mechanism, and the line light source drive mechanism, a light source operation control step of operating the flat light source and the line light source, and an imaging control step of operating the imaging unit, An appearance inspection method that includes a multiple rotation position imaging image acquisition step of using the drive mechanism control step, the light source operation control step, and the imaging control step to obtain a plurality of imaging images of the subject including reflected light reflected by the subject of planar light from the flat light source and a plurality of imaging images of the subject including transmitted light transmitted through the subject of linear light from the line light source when the subject held by the holding unit is located at a plurality of rotation positions by driving the rotation mechanism.

15. The appearance inspection method according to Claim 14, The multiple rotation position imaging image acquisition step is an appearance inspection method performed in a state where the position of the flat light source, the position of the line light source, and the position of the imaging device are controlled to specific positions.

16. The appearance inspection method according to Claim 15, The multiple rotation position imaging image acquisition step is an appearance inspection method in which the positions of the flat light source, the line light source, and the imaging device that are controlled to specific positions are controlled to another specific position and performed multiple times.

17. A holding part that is rotatably supported on the inner wall of the through hole of the base and holds the subject, a rotation mechanism that rotates the holding part around a rotation axis extending in the direction of the through hole, and a first side that is on one side in the direction of the through hole from the holding part. An imaging unit that images the subject held by the holding unit, an imaging unit drive mechanism that changes the position of the imaging unit with respect to the base and the imaging direction, a flat light source that is disposed on the first side and can irradiate the subject held by the holding unit with planar light, A flat light source drive mechanism that changes the position of the flat light source with respect to the base and the irradiation direction with respect to the subject held by the holding unit, and a second side that is on the opposite side of the first side from the holding unit. A line light source that can irradiate the subject held by the holding unit with linear light, and a line light source drive mechanism that changes the position of the line light source with respect to the base and the irradiation direction with respect to the subject held by the holding unit. An appearance inspection program for inspecting the appearance of the subject, The drive mechanism control step for driving the rotation mechanism, the imaging unit drive mechanism, the flat light source drive mechanism, and the line light source drive mechanism, the light source operation control step for operating the flat light source and the line light source, and the imaging control step for operating the imaging unit are executed by a computer. An appearance inspection program that performs a plurality of rotation position imaging image acquisition steps of acquiring a plurality of imaging images of the subject including reflected light reflected by the subject of the planar light from the flat light source and a plurality of imaging images of the subject including transmitted light transmitted through the subject of the linear light from the line light source when the subject held by the holding unit is located at a plurality of rotation positions by driving the rotation mechanism using the drive mechanism control step, the light source operation control step, and the imaging control step.

18. The appearance inspection program according to Claim 17, The plurality of rotation position imaging image acquisition steps are performed in a state where the position of the flat light source, the position of the line light source, and the position of the imaging device are controlled to specific positions.

19. The appearance inspection program according to Claim 18, The multiple rotational position imaging image acquisition step is an appearance inspection program that controls the positions of the flat light source, the line light source, and the imaging device, which are controlled to specific positions, to another specific position and performs the operations multiple times.

Images