Lens appearance inspection device

Abstract

According to the present invention: a lens defect can be detected with higher accuracy as compared with a conventional inspection device; and a lens image necessary for image inspection can be captured without adjusting the position and angle of illumination each time.　Provided is a lens appearance inspection device comprising: a first inspection unit that uses transmitted illumination to capture an image including a lens under inspection; a second inspection unit that uses side illumination to capture an image including the lens under inspection; a third inspection unit that uses coaxial epi-illumination and dome illumination to capture an image including the lens under inspection; and a control unit that detects defects in the lens under inspection on the basis of the captured images. The lens appearance inspection device is characterized in that the lens under inspection is conveyed to the first inspection unit, the second inspection unit, and the third inspection unit in a state of being held by a lens holder, and the image of the lens under inspection can be captured by changing the angle of the lens holder.

Description

Lens Appearance Inspection Apparatus

[0001] The present invention relates to a lens appearance inspection apparatus.

[0002] Conventionally, there is known an inspection apparatus that inspects an inspection object such as a lens by analyzing an image captured by a camera. In such an inspection apparatus, the inspection object is imaged by an imaging method using a bright-field illumination method, a dark-field illumination method, or a method combining these two illumination methods, and image inspection of the inspection object is performed.

[0003] Japanese Unexamined Patent Application Publication No. 2002-90258

[0004] Such an inspection apparatus can detect defects such as scratches and stains by analyzing the image of the inspection object captured using the above illumination method, and can discriminate between non-defective products and defective products for the inspection object.

[0005] However, in the image inspection of the conventional inspection apparatus, imaging using illumination is insufficient, and all defects of the lens cannot be detected. Further, in the conventional inspection apparatus, when imaging different types of lenses, or when lens scratches or the like are not clearly shown in the captured image, it is necessary to adjust the position and angle of the illumination, and the illumination adjustment work requires labor each time.

[0006] The present invention aims to address such circumstances. That is, it is an object of the present invention to improve the accuracy of lens defect detection compared to conventional inspection apparatuses, and to enable imaging of the lens required for image inspection without adjusting the position and angle of illumination each time.

[0007] To solve these problems, the present invention has the following configuration: A lens appearance inspection apparatus comprising: a first inspection unit that captures an image including the lens to be inspected using transmitted illumination; a second inspection unit that captures an image including the lens to be inspected using side illumination; a third inspection unit that captures an image including the lens to be inspected using coaxial incident illumination and dome illumination; and a control unit that detects defects in the lens to be inspected based on the images captured by each unit, wherein the lens to be inspected is transported to the first inspection unit, the second inspection unit, and the third inspection unit while being held in a lens holder, and the lens to be inspected can be imaged by changing the angle of the lens holder.

[0008] The lens appearance inspection device of the present invention, having these features, can improve the accuracy of detecting lens defects compared to conventional inspection devices, and can capture images of the lens necessary for image inspection without having to adjust the position and angle of the illumination each time.

[0009] A plan view showing the overall configuration of a lens appearance inspection device according to an embodiment of the present invention. A diagram showing a lens holder being transported in a lens appearance inspection device according to an embodiment of the present invention. A diagram showing the first inspection section in a lens appearance inspection device according to an embodiment of the present invention. A diagram showing the second inspection section in a lens appearance inspection device according to an embodiment of the present invention. A diagram showing the third inspection section in a lens appearance inspection device according to an embodiment of the present invention. A flowchart showing a series of lens inspection processes in a lens appearance inspection device according to an embodiment of the present invention.

[0010] Embodiments of the present invention will now be described with reference to the drawings. In the following description, the same reference numerals in different figures indicate parts with the same function, and redundant explanations in each figure will be omitted as appropriate. In each figure, the X-axis and Y-axis directions indicate the horizontal direction, and the Z-axis direction indicates the vertical direction.

[0011] An example of the configuration of the lens appearance inspection device 1 will be explained using Figure 1. As shown in Figure 1, the lens appearance inspection device 1 consists of a lens loading unit 10, a lens holder transport unit 20, three types of inspection units 30, and a control unit 100 that controls these. The lens appearance inspection device 1 is a device that automatically inspects the lens 2 by having the lens to be inspected 2 held in a lens holder 40 (described later) in the lens loading unit 10, and then transporting the lens holder 40 to the three types of inspection units 30 by the lens holder transport unit 20. In this embodiment, the lens 2 is, for example, an eyeglass lens or a camera lens.

[0012] The lens loading section 10 includes, for example, a mounting table 11, a waiting table 12, a cleaning section 13, and a holder transfer machine 14. In the lens appearance inspection device 1, the lenses 2 to be inspected are loaded and unloaded using the mounting table 11 (hereinafter also referred to as the loading section or unloading section). As shown in Figure 1, the holder transfer machine 14 has three gripping sections 15, each gripping section 15 gripping the lens holder 40 and rotating the holder transfer machine 14 to move the lens from the mounting table 11 to the waiting table 12, from the waiting table 12 to the cleaning section 13, and from the transport tray 26 (described later) back to the mounting table 11. In the lens appearance inspection device 1, the lenses 2 to be inspected are loaded onto the mounting table 11 and held by the lens holder 40, and after dust and other debris are removed in the cleaning section 13, they are sequentially transported to each inspection section 30 by the lens holder transport section 20.

[0013] The lens holder transport unit 20 includes, as an example, a plurality of holder chucks 21, a chuck rail 22 provided for each holder chuck 21, a movable plate 23, a conveyor 24, a temporary gripping unit 25, a transport tray 26, and a tray rail 27. The holder chucks 21 are attached to the chuck rails 22 so as to be movable along the chuck rails 22, and the chuck rails 22 are fixed to the movable plate 23. The holder chucks 21 are equipped with a mechanism for gripping the lens holder 40, and the lens holder transport unit 20 can transport the lens holder 40 to the inspection units 30 described later by gripping the lens holder 40 with the holder chucks 21 and moving the holder chucks 21 on the chuck rails 22 and movable plate 23. As shown in Figure 1, the lens appearance inspection device 1 of this embodiment is equipped with four holder chucks 21, from the first holder chuck 21A to the fourth holder chuck 21D.

[0014] The chuck rail 22 is provided to allow the holder chuck 21 to move in the Y-axis direction. The holder chuck 21 can move along the chuck rail 22 in the Y-axis direction as shown by arrow A in the figure. The movable plate 23 is provided to allow the movement of multiple holder chucks 21 in the X-axis direction as shown. Each of the multiple chuck rails 22 is fixed to one movable plate 23, and a conveyor 24 is provided below the movable plate 23 along the X-axis direction as shown. The movable plate 23 moves in the X-axis direction as shown by arrow B as the conveyor 24 rotates. As the movable plate 23 moves in the X-axis direction as shown, the chuck rail 22 fixed to the movable plate 23 and the holder chucks 21 attached to the chuck rail 22 can move in the X-axis direction as shown. In this way, by moving the holder chucks 21 in the X-axis direction and the Y-axis direction as shown, the lens holders 40 can be sequentially transported to each inspection unit 30.

[0015] Specifically, the first holder chuck 21A receives the lens holder 40 holding the lens 2 that has been cleaned in the cleaning unit 13 from the cleaning unit 13, transports it to the first inspection unit 30A, and hands it over to the first inspection unit 30A. The second holder chuck 21B receives the lens 2 (lens holder 40) that has been inspected in the first inspection unit 30A from the first inspection unit 30A, transports it to the second inspection unit 30B, and hands it over to the second inspection unit 30B. The third holder chuck 21C receives the lens 2 (lens holder 40) that has been inspected in the second inspection unit 30B from the second inspection unit 30B, transports it to the third inspection unit 30C, and hands it over to the third inspection unit 30C. The fourth holder chuck 21D receives the lens 2 (lens holder 40) that has been inspected in the third inspection unit 30C from the third inspection unit 30C, and transports it to the temporary gripping unit 25. The temporary gripping unit 25 temporarily grips the lens holder 40, which holds the lens 2 after all inspections have been completed in the inspection units 30, to the removal unit (mounting table 11) during the process of transporting the lens holder 40 to the removal unit (mounting table 11).

[0016] The transport tray 26 transports the lens holder 40, which holds the inspected lens 2, to the lens loading section 10. The transport tray 26 moves along the tray rail 27, which, as shown in Figure 1, connects the temporary gripping section 25 and the gripping section 15 of the holder moving machine 14. In the lens appearance inspection device 1, the transport tray 26 and the tray rail 27 are located lower vertically (in the Z-axis direction shown) than the holder chuck 21, etc. That is, the transport tray 26 moving along the tray rail 27 moves vertically below (in the negative Z-axis direction shown) the holder chuck 21 and chuck rail 22 in Figure 1.

[0017] The temporary gripping unit 25 is equipped with a gripping arm 25A and a gripping rail 25B for gripping the lens holder 40. The gripping arm 25A can move up and down vertically (in the Z-axis direction in the illustration) along the gripping rail 25B. When the gripping arm 25A receives the lens holder 40 from the fourth holder chuck 21D, it waits for the arrival of the transport tray 26. When the transport tray 26 arrives, it descends along the gripping rail 25B and places the gripped lens holder 40 onto the transport tray 26. The transport tray 26 with the lens holder 40 on it moves along the tray rail 27 from the temporary gripping unit 25 towards the gripping unit 15 of the holder mover 14. When the transport tray 26 arrives at the gripping unit 15 of the holder mover 14, the gripping unit 15 grips the lens holder 40 placed on the transport tray 26 and moves it to the mounting table 11. In the lens appearance inspection device 1, each operation of the lens holder transport unit 20 is controlled by the control unit 100.

[0018] The inspection unit 30 inspects the lens 2 held in the lens holder 40. As shown in Figure 1, the lens appearance inspection device 1 has three inspection units 30: the first inspection unit 30A to the third inspection unit 30C. The inspection unit 30 has an inlet / outlet 31 for the lens holder 40 on the side facing the negative Y-axis in Figure 1, and the lens holder transport unit 20 loads and unloads the lens holder 40 into and out of the inspection unit 30 from the inlet / outlet 31. Each inspection unit 30 is provided with a holder gripping unit 32 for gripping the lens holder 40, and the holder gripping unit 32 receives the loaded lens holder 40 and delivers the lens holder 40.

[0019] In the inspection unit 30, an inspection is performed to detect defects in the lens 2 to be inspected, such as scratches, dirt, shape distortion, and coating defects. Specifically, each inspection unit 30 uses a different illumination method to image the lens 2, and the control unit 100 inspects the images captured by each inspection unit 30 to detect defects in the lens 2. Imaging of the lens 2 in each inspection unit 30 is performed with the holder gripping unit 32 gripping the lens holder 40, and the holder gripping unit 32 can tilt and rotate the lens holder 40. The lens 2 is tilted and rotated while held in the lens holder 40, and the inspection unit 30 can perform inspection of the lens 2 at various angles. A detailed explanation of each of the three types of inspection units 30 will be described later with reference to Figures 3 to 5.

[0020] The control unit 100 includes a CPU, ROM, RAM, and an I / F (none of which are shown), and controls the lens loading unit 10, the lens holder transport unit 20, and each inspection unit 30 by executing various processes based on a program stored in the ROM using the CPU. The ROM, which is provided as a non-volatile memory element, stores a program for controlling the lens appearance inspection device 1 based on the input information, and various data necessary to execute this program.

[0021] The control unit 100 performs image inspection on the images of the lens 2 input from each of the three inspection units 30, and determines whether or not there are defects in the lens 2, that is, whether the lens 2 is a good product or a defective product.

[0022] Next, the lens holder 40 will be described using Figure 2. As shown in Figure 2, the lens holder 40 comprises a holder body 41, a plurality of retaining arms 42, an arm lever 43, and a handle portion 44. The holder body 41 is annular, and a placement space S1 for arranging the lens 2 to be inspected is formed inside the annular shape. The lens holder 40 shown in Figure 2 has five retaining arms 42, and the five retaining arms 42 extend toward the placement space S1 from their respective arm holes 411 formed on the inner circumference of the holder body 41. The five retaining arms 42 are evenly distributed within the placement space S1.

[0023] The holding arm 42 is composed of, for example, an arm portion 421, a holding portion 422, and a flange portion 423. As shown in Figure 2, the tip of the arm portion 421, which extends from the arm hole 411, is provided with a cylindrical holding portion 422 that extends vertically. The lens 2 held by the lens holder 40 is held by its outer edge contacting the sides of the holding portions 422 of the multiple holding arms 42. The outer circumference of the cylindrical holding portion 422 is covered with a material that has high cushioning properties and is not slippery, so the lens 2 that comes into contact with the holding portion 422 is less likely to be scratched and is less likely to slip. In addition, flange portions 423 are provided at both ends of the holding portion 422 in the vertical direction to prevent the lens 2 held by the holding portion 422 from falling.

[0024] The holding arms 42 open and close relative to the placement space S1 by operating an arm lever 43 provided on the outer circumference of the holder body 41. Specifically, when the arm lever 43 is operated, the arm portion 421 of each holding arm 42 is housed within the holder body 41, and the holding portion 422 moves in the direction of the arrow shown in the figure, opening relative to the placement space S1. The arm lever 43 has a mechanism that automatically returns to its pre-operation state when the operation is released, and the holding portion 422 moves in the opposite direction to the arrow shown in the figure, closing relative to the placement space S1. When holding a lens 2 with the lens holder 40, the arm lever 43 is operated to open the holding arms 42 relative to the placement space S1, and after placing the lens 2 in the placement space S1, the operation of the arm lever 43 is released. In the process of releasing the operation of the arm lever 43 and closing the holding arms 42 relative to the placement space S1, the holding portions 422 of the multiple holding arms 42 come into contact with the outer edge of the lens, thereby holding the lens 2. In the lens appearance inspection device 1, the operation of the arm lever 43 is performed automatically by the operation unit 16 provided in the lens loading unit 10.

[0025] Thus, the lens holder 40, which holds the lens 2 with multiple holding arms 42, can hold the lens 2 as long as the multiple holding arms 42 can contact the outer edge of the lens 2 in the arrangement space S1 surrounded by the annular holder body 41. Therefore, even when holding a lens 2 that is not perfectly circular (for example, elliptical), it can be held without changing the design of the lens holder 40. In this embodiment, the lens 2 is stably held by three or more holding arms 42 contacting the lens 2. Furthermore, in order to stably hold a lens 2 of any outer edge shape by having three or more holding arms 42 contact it, it is desirable that the number of holding arms 42 be an odd number, for example, five or more.

[0026] Furthermore, it is desirable that the radius of the flange portion 423 be 3 mm longer than the radius of the cylindrical holding portion 422. In this embodiment, the inspection of the lens 2 performed in the inspection unit 30 is performed on the area 3 mm inward from the outer edge of the lens 2 to be inspected. That is, if the radius of the flange portion 423 is 3 mm or more longer than the radius of the holding portion 422 that holds the lens 2, the flange portion 423 will intrude into the area being inspected during the inspection of the lens 2, reducing the accuracy of the inspection. On the other hand, for example, if the radius of the flange portion 423 is 3 mm or less (for example, 2 mm) longer than the holding portion 422 that holds the lens 2, the flange portion 423 will not intrude into the area being inspected, but when the lens 2 held by the holding portion 422 slips, the surface area on which the flange portion 423 catches the lens 2 becomes smaller, impairing the performance of preventing the lens 2 from falling. In addition to the example of this embodiment, if the inspection of the lens 2 by the inspection unit 30 is performed on the area X mm inward from the outer edge of the lens 2 to be inspected, then it is desirable that the radius of the flange 423 be X mm longer than the radius of the holding unit 422.

[0027] As shown in Figure 2, the lens holder 40 has handle portions 44 that protrude from the holder body 41 in the outer peripheral direction, 180 degrees opposite to each other with respect to the arrangement space S1. The handle portions 44 are used when the holder gripping portion 32 of the inspection unit 30 grips the lens holder 40. When the holder gripping portion 32 grips the lens holder 40, it grips the lens holder 40 by sandwiching the handle portions 44 from the left and right (horizontal direction) so that the protrusions 323 (see Figure 1) are inserted into the handling recesses 45 provided on the handle portions 44.

[0028] Next, the inspection in the first inspection section 30A to the third inspection section 30C will be explained using Figures 3 to 5. The first inspection section 30A to the third inspection section 30C are box-shaped enclosures with light-shielding properties, and Figures 3 to 5 illustrate the inside of the enclosures of the first inspection section 30A to the third inspection section 30C.

[0029] First, the first inspection unit 30A will be described using Figure 3. The first inspection unit 30A is an inspection unit 30 that performs imaging of the lens 2 using transmitted illumination. Figure 3 shows the inside of the housing of the first inspection unit 30A, which includes an imaging unit 34A, a holder gripping unit 32A, and a lower illumination unit 35. The inner surface of the housing of the first inspection unit 30A is an anti-reflective surface that has been treated to reduce the reflectivity of light, for example, by blackening. Alternatively, an anti-reflective film may be attached to the inner surface of the housing to form an anti-reflective surface.

[0030] The imaging unit 34A comprises a camera body 341A and a camera lens 342A. The camera lens 342A is mounted vertically below the camera body 341A, and the camera body 341A comprises an image sensor (not shown) and a storage means (not shown). Under the control of the control unit 100, the imaging unit 34A captures an image with the image sensor via the camera lens 342A, stores the captured image in the storage means, and transmits it to the control unit 100. The image sensor here may be, for example, an area sensor.

[0031] The holder gripping section 32A grips the lens holder 40 that has been transported into the housing of the first inspection section 30A by the first holder chuck 21A, and continues to grip the lens holder 40 until the inspection in the first inspection section 30A is completed and the lens holder 40 is handed over to the second holder chuck 21B. As an example, the holder gripping section 32A is composed of a support 324A, a gripping machine 321A, and left and right holder gripping arms 322, as shown in Figure 3. The holder gripping arms 322 move in the left-right direction (X-axis direction in the figure), and the left and right holder gripping arms 322 grip the lens holder 40 by sandwiching the handle portion 44 of the lens holder 40 from the left and right, and fix the lens holder 40 by inserting the protrusion 323 into the handling recess 45 formed in the handle portion 44. In the first inspection section 30A, the lens holder 40 is held so that the concave surface of the lens 2 faces upward. The state shown in Figure 3 is when the convex portion 323 of the holder gripping portion 32A is inserted into the handling recess 45 formed in the handle portion 44 of the lens holder 40.

[0032] The lower illumination unit 35 is positioned vertically below the lens holder 40 gripped by the holder gripping unit 32A. The lower illumination unit 35 can be, for example, a tablet PC. In this embodiment, the tablet PC is placed on the stage 351, and illumination light is shone vertically upward from the tablet PC. The transmitted light, which passes through the lens 2, is captured by the imaging unit 34A. The lower illumination unit 35 is controlled by the control unit 100 to emit illumination light with specific patterns that make it easier to highlight defects in the lens 2, such as striped patterns or multiple circular patterns. In the first inspection unit 30A, by emitting illumination light with multiple types of patterns from the lower illumination unit 35 during the inspection of the lens 2, defects that would not be detected with a single pattern of illumination can be detected, thereby improving the accuracy of defect detection.

[0033] The first inspection unit 30A, which images the lens 2 using transmitted illumination, can detect defects such as air bubbles inside the lens 2 and distortions in the shape of the lens 2. The control unit 100 can also adjust the intensity of the illumination light from the lower illumination unit 35.

[0034] Furthermore, the first inspection unit 30A is equipped with a lifting rail 39A, and the support 324A of the holder gripping unit 32A is attached to the lifting rail 39A. The holder gripping unit 32A can move up and down along the lifting rail 39A, and by moving it up and down while gripping the lens holder 40, the vertical position of the lens 2 during imaging (in the Z-axis direction shown) can be adjusted. This allows the distance between the imaging unit 34A and the lens 2 to be adjusted, and the first inspection unit 30A can position the lens 2 at an appropriate height according to conditions such as the type of lens 2 to be inspected, and perform inspection under appropriate conditions corresponding to the lens 2.

[0035] Next, the second inspection unit 30B will be described using Figure 4. The second inspection unit 30B is an inspection unit 30 that performs imaging of the lens 2 using side illumination. Figure 4 is a diagram showing the inside of the second inspection unit 30B, and includes an imaging unit 34B, a holder gripping unit 32B, a ring illumination unit 36, and a diffusion prevention unit 33. The inner surface of the housing of the second inspection unit 30B is an anti-reflective surface that has been treated to reduce the reflectivity of light, similar to the first inspection unit 30A, and is, for example, blackened.

[0036] The imaging unit 34B comprises a camera body 341B and a camera lens 342B. Similar to the imaging unit 34A, the camera lens 342B is mounted vertically below the camera body 341B, and the camera body 341B comprises an image sensor (not shown) and a storage means (not shown). Under the control of the control unit 100, the imaging unit 34B captures an image with the image sensor via the camera lens 342B, stores the captured image in the storage means, and transmits it to the control unit 100.

[0037] The holder gripping section 32B grips the lens holder 40 that has been transported into the housing of the second inspection section 30B by the second holder chuck 21B, and continues to grip the lens holder 40 until the inspection in the second inspection section 30B is completed and the lens holder 40 is handed over to the third holder chuck 21C. As an example, the holder gripping section 32B is composed of a support 324B, a gripping machine 321B, and left and right holder gripping arms 322, as shown in Figure 4. The gripping operation of the lens holder 40 is the same as that of the holder gripping section 32A. In the second inspection section 30B, the holder gripping section 32B grips the lens holder 40 so that the concave surface of the lens 2 faces upward. Furthermore, the gripping device 321B has a mechanism that tilts with respect to the support 324B in the X-axis direction and the Y-axis direction while gripping the lens holder 40, so that the lens holder 40 can be tilted in the X-axis direction and the Y-axis direction. By tilting the lens holder 40, the light from the ring illumination unit 36 ​​that irradiates illumination light onto the lens 2 can be reflected at various angles, allowing an image of the lens 2 to be captured, thereby improving the accuracy of detecting defects in the lens 2.

[0038] As shown in Figure 4, the ring illumination unit 36 ​​is positioned diagonally above the lens holder 40 gripped by the holder gripping unit 32B. The ring illumination unit 36 ​​consists of eight illumination units 361 arranged in a ring shape on a circular illumination support plate 362. Each illumination unit 361 is equipped with an illumination LED (not shown) and an illumination lens (not shown) for illuminating the lens 2 with illumination light. The ring illumination unit 36 ​​is also equipped with a lifting mechanism 363, which allows the vertical position of the illumination units 361 to be adjusted. In this embodiment, illumination light is irradiated onto the lens 2 from diagonally above by the ring illumination unit 36, and the diffused light reflected from the surface of the lens 2 is captured by the imaging unit 34B. As described above, the holder gripping unit 32B can tilt the lens holder 40 about the Y-axis direction shown in the figure. In the second inspection unit 30B, the accuracy of detecting defects in the lens 2 can be improved by tilting the lens holder 40 and taking images at various angles during the inspection of the lens 2.

[0039] The diffusion prevention section 33 is provided at the lower part of the second inspection section 30B and prevents the diffusion of illumination light emitted from the ring illumination section 36. The diffusion prevention section 33 has a roughly frustoconical shape that is narrow at the bottom and reflects the illumination light emitted from the ring illumination section 36 vertically downward within the diffusion prevention section 33, preventing unwanted reflected light from entering the imaging section 34B. As described above, the inner surface of the housing of the second inspection section 30B is an anti-reflective surface with an anti-reflective coating that reduces the reflectivity of light, so the diffusion prevention section 33 may be provided only as needed.

[0040] The second inspection unit 30B, which images the lens 2 using side illumination, can detect elongated defects such as dirt and scratches on the lens 2. Furthermore, the illumination angle to the lens 2 can be easily adjusted by tilting the lens holder 40, eliminating the need to change the angle of the ring illumination unit 36 ​​each time.

[0041] The control unit 100 can adjust the intensity of the illumination light and the illumination pattern of the ring illumination unit 36. Specifically, the ring illumination unit 36 ​​may emit illumination light from all of the illumination LEDs of the eight illumination units 361, or it may emit illumination light from only some of the illumination LEDs. Alternatively, the illumination light may be emitted from only four of the eight illumination units 361, with every other unit being used. Furthermore, although the embodiment was described as having eight illumination units 361, there may be seven or fewer, or nine or more.

[0042] Furthermore, the second inspection unit 30B is equipped with a lifting rail 39B, similar to the first inspection unit 30A, and the support 324B of the holder gripping unit 32B is attached to the lifting rail 39B. The holder gripping unit 32B can move up and down along the lifting rail 39B, and by moving it up and down while gripping the lens holder 40, the vertical position of the lens 2 during imaging (in the Z-axis direction shown) can be adjusted. This allows the distance between the imaging unit 34B and the lens 2 to be adjusted, and the second inspection unit 30B can also position the lens 2 at an appropriate height according to conditions such as the type of lens 2 to be inspected, and perform inspection under appropriate conditions corresponding to the lens 2.

[0043] Next, the third inspection unit 30C will be described with reference to FIG. 5. The third inspection unit 30C is an inspection unit 30 that images the lens 2 using coaxial epi-illumination and dome illumination. FIG. 5 is a diagram showing the interior of the third inspection unit 30C, which includes an imaging unit 34C, a holder gripping unit 32C, a coaxial irradiation unit 37, and a dome irradiation unit 38. The inner surface of the housing of the third inspection unit 30C is an antireflective surface that has been subjected to antireflection processing to reduce light reflectivity, similar to the first inspection unit 30A and the like, and is, for example, subjected to blackening treatment.

[0044] The imaging unit 34C includes a camera body 341C and a camera lens 342C. Similar to the imaging unit 34A and the like, the camera lens 342C is mounted vertically below the camera body 341C, and the camera body 341C includes an imaging element (not shown) and a storage means (not shown). Under the control of the control unit 100, the imaging unit 34C captures an image with the imaging element through the camera lens 342C, stores the captured image in the storage means, and transmits the image to the control unit 100.

[0045] The holder gripping unit 32C grips the lens holder 40 that has been conveyed into the housing of the third inspection unit 30C by the third holder chuck 21C, and continues gripping the lens holder 40 until the inspection at the third inspection unit 30C is completed and the lens holder 40 is delivered to the fourth holder chuck 21D. As an example, as shown in FIG. 5, the holder gripping unit 32C is composed of a support 324C, a gripper 321C, and left and right holder gripping arms 322. The gripping operation of the lens holder 40 is the same as that of the holder gripping unit 32A and the like. The gripper 321C has a mechanism that rotates around the Y-axis direction shown in the drawing relative to the support 324C while gripping the lens holder 40, and can rotate the lens holder 40. In the third inspection unit 30C, the lens holder 40 is rotated, and the lens 2 to be inspected is inspected in both a state where the concave surface faces upward and a state where the convex surface faces upward.

[0046] The coaxial irradiation unit 37 includes an illumination device 371 and a half mirror 372. The half mirror 372 is disposed at an angle of approximately 45 degrees relative to the illumination device 371. The illumination device 371 is a planar device that emits illumination light, and part of the illumination light emitted from the illumination device 371 is reflected by the half mirror 372, passes through the hole 373, and travels vertically downward. The light reflected by the half mirror 372 is reflected on the surface of the lens 2, becomes specularly reflected light, and travels vertically upward. The specularly reflected light passes through the hole 373, transmits through the half mirror 372, and enters the imaging unit 34C. The imaging unit 34C captures an image of the incident specularly reflected light.

[0047] Further, the dome irradiation unit 38 is provided to supplement the light amount on the outer peripheral side of the lens 2. In the third inspection unit 30C, the illumination light emitted to the lens 2 by the coaxial irradiation unit 37 has a small light spread and is emitted to the lens 2 with a diameter smaller than the diameter of the lens 2, so that the illumination light cannot be applied to the entire lens 2 which is the inspection target. The dome irradiation unit 38 has a dome shape and includes an illumination device (not shown) on the inner side. The dome irradiation unit 38 diffusely reflects the irradiation light emitted by the illumination device (not shown) on the inner surface of the dome, and irradiates the diffused light toward the lens 2. Thereby, it is possible to illuminate the outer peripheral side of the lens 2 that cannot be covered by the irradiation of the coaxial irradiation unit 37, and it is possible to illuminate the entire lens 2 with the illumination light. The coaxial irradiation unit 37 and the dome irradiation unit 38 communicate with each other through the hole 373.

[0048] In the third inspection unit 30C, in the inspection of the lens 2, the lens holder 40 is rotated to perform imaging on both surfaces of the lens 2, whereby the defect detection rate of the lens 2 can be improved.

[0049] The third inspection unit 30C, which performs imaging of the lens 2 by coaxial epi-illumination and dome illumination, can detect defects such as coating defects, thickness unevenness, interference fringes, and residual film of the lens 2. In addition, the control unit 100 can adjust the illumination intensity of the coaxial irradiation unit 37 and the dome irradiation unit 38.

[0050] Furthermore, the third inspection unit 30C is equipped with a lifting rail 39C, similar to the first inspection unit 30A, and the support 324C of the holder gripping unit 32C is attached to the lifting rail 39C. The holder gripping unit 32C can move up and down along the lifting rail 39C, and by moving it up and down while gripping the lens holder 40, the vertical position of the lens 2 during imaging (in the Z-axis direction shown) can be adjusted. This allows the distance between the imaging unit 34C and the lens 2 to be adjusted, and the third inspection unit 30C can also position the lens 2 at an appropriate height according to conditions such as the type of lens 2 to be inspected, and perform inspection under appropriate conditions corresponding to the lens 2.

[0051] As described above using the three types of inspection units 30 shown in Figures 3 to 5, the accuracy of detecting defects in the lens 2 can be improved by capturing an image that includes the lens 2.

[0052] Furthermore, in the above description, in this embodiment, the holder gripping portion 32B was described as having a mechanism for tilting the lens holder 40 around the X-axis and Y-axis directions shown in the figure, and the holder gripping portion 32C was described as having a mechanism for rotating the lens holder 40 around the Y-axis direction shown in the figure. However, it is also possible that all of the holder gripping portions 32A to 32C similarly have mechanisms that allow the lens holder 40 to be tilted and rotated.

[0053] The control unit 100 can determine whether or not there are defects in the lens 2 based on the image information input from the first inspection unit 30A to the third inspection unit 30C of the lens 2, using a trained model. The trained model is a program stored in the ROM of the CPU of the control unit 100. By using a trained model suitable for the inspection content of each inspection unit 30, defects in the lens 2 can be detected with high accuracy according to the respective inspection content.

[0054] Specifically, the control unit 100 stores images of normal lenses, i.e., lenses without defects, captured by the respective illumination methods of each inspection unit 30. The stored images of normal lenses are images taken from the front and back surfaces of the lens and from various angles. The trained model provided in the control unit 100 compares the captured images of lens 2 with the stored images of normal lenses corresponding to the surface and angle of lens 2 to detect abnormalities. The trained model can create a defect distribution map based on the degree of abnormality for the detected abnormalities. Then, the defect status of lens 2 is determined by performing blob analysis on the created distribution map. The determination of defects in lens 2 by blob analysis can be performed in multiple stages, for example, in three stages: "normal," "gray zone," and "abnormal."

[0055] Furthermore, defects may be detected using other determination methods. For example, the control unit 100 stores images of lenses with defects captured by each illumination method of each inspection unit 30. The stored images are images of lenses with various defects that can be detected by each illumination method, and the trained model of the control unit 100 compares the captured image of lens 2 with the stored images of multiple lenses with various defects to detect defects in lens 2. For example, as described above, the first inspection unit 30A is an inspection unit 30 that mainly detects air bubbles and shape distortions in lens 2, but the image captured by the first inspection unit 30A is compared with multiple images of lenses with various patterns of air bubbles and shape distortions stored in the control unit 100, and if a defect that is substantially identical or similar to the stored image is detected, the control unit 100 determines that there is a defect in lens 2.

[0056] Furthermore, when determining whether a defect exists, the determination may be based on the degree of similarity to the defect in the stored image. That is, even if a defect similar to the stored image is detected, if the detected defect is extremely minute, it may be determined that there is no defect. In the lens appearance inspection device 1, which uses a trained model to detect defects, it is desirable that the control unit 100 stores a large number of defect types and patterns in the images to improve the accuracy of defect detection, and that images taken at as many different angles as possible of the lens are stored.

[0057] Furthermore, the detection and determination of defects in lens 2 using the trained model is not limited to the method described above; defects in lens 2 may be detected and determined by different methods.

[0058] Furthermore, the control unit 100 may be able to optimize imaging conditions by changing inspection parameters according to the SPH spherical power, CYL cylindrical power, and thickness of the lens 2 to be inspected. Specifically, the control unit 100 may be able to control the lifting rails 39A to 39C, the lower illumination unit 35, the ring illumination unit 36, the coaxial illumination unit 37, and the dome illumination unit 38 according to the SPH spherical power, CYL cylindrical power, and thickness of the lens 2 to be inspected, thereby automatically adjusting the height of the lens 2 to be inspected and automatically changing the intensity and content of each illumination.

[0059] Next, a series of inspection steps for the lens 2 in the lens appearance inspection device 1 will be described. First, the lens 2 to be inspected is placed in the input section (mounting table 11) of the lens loading section 10 and held in the lens holder 40 (step S01). Then, the lens holder 40 holding the lens 2 is transported to the cleaning section 13 by the holder transfer machine 14, where a cleaning process is performed to remove dirt, debris, etc. adhering to the lens 2 (step S02).

[0060] After processing in the cleaning unit 13 is completed, the lens holder 40 is transported from the cleaning unit 13 to the first inspection unit 30A by the first holder chuck 21A (step S03). After the holder gripping unit 32A of the first inspection unit 30A receives the lens holder 40 from the first holder chuck 21A, the lens 2 is inspected in the first inspection unit 30A (step S04). The image captured during the inspection in the first inspection unit 30A is transmitted to the control unit 100.

[0061] After the inspection in the first inspection unit 30A is completed, the lens holder 40 is transported from the first inspection unit 30A to the second inspection unit 30B by the second holder chuck 21B (step S05). After the holder gripping unit 32B of the second inspection unit 30B receives the lens holder 40 from the second holder chuck 21B, the lens 2 is inspected in the second inspection unit 30B (step S06). The image captured during the inspection in the second inspection unit 30B is transmitted to the control unit 100.

[0062] After the inspection in the second inspection unit 30B is completed, the lens holder 40 is transported from the second inspection unit 30B to the third inspection unit 30C by the third holder chuck 21C (step S07). After the holder gripping unit 32C of the third inspection unit 30C receives the lens holder 40 from the third holder chuck 21C, the lens 2 is inspected in the third inspection unit 30C (step S08). The image captured during the inspection in the third inspection unit 30C is transmitted to the control unit 100.

[0063] Once the inspection in the third inspection unit 30C is complete, the control unit 100 inspects the images of the lens 2 input from each inspection unit 30 using the corresponding trained model and determines whether there are any defects in the lens 2 (step S09).

[0064] After the inspection in the third inspection section 30C is completed, the lens holder 40 is transported from the third inspection section 30C to the temporary gripping section 25 by the fourth holder chuck 21D, then transported to the lens loading section 10 by the transport tray 26, and finally transported to the removal section (mounting table 11) (step S10). The lens holder 40 then releases its grip on the lens 2, and the lens 2 is removed (step S11).

[0065] The lens 2 is inspected by the lens appearance inspection device 1 in the sequence of steps described above using Figure 6. In the explanation in Figure 6, the control unit 100 receives image information captured by each inspection unit 30 and determines defects in the lens 2 using a learned model corresponding to each inspection. However, each inspection unit 30 may also determine defects in the lens 2 using a learned model. Specifically, each inspection unit 30 may be equipped with a control unit that has a learned model, and for example, it may score the imaged lens 2 based on the detected defects and send only the scoring results to the control unit 100. The control unit 100 may then determine whether the lens 2 is good or defective by combining the scoring results input from the control units of each inspection unit 30.

[0066] As described in detail above with reference to the drawings regarding the embodiment, the lens appearance inspection device 1 comprises a first inspection unit 30A that captures an image including the lens 2 to be inspected using transmitted illumination, a second inspection unit 30B that captures an image including the lens 2 to be inspected using side illumination, a third inspection unit 30C that captures an image including the lens 2 to be inspected using coaxial incident illumination and dome illumination, and a control unit 100 that detects defects in the lens 2 to be inspected based on the images captured by each unit. The lens 2 to be inspected is transported to the first inspection unit 30A, the second inspection unit 30B, and the third inspection unit 30C while being held in a lens holder 40, and the lens 2 to be inspected can be imaged by changing the angle of the lens holder 40. Such a lens appearance inspection device 1 can improve the accuracy of detecting defects in the lens 2 during inspection, and can capture the lens 2 necessary for image inspection without having to adjust the position and angle of the illumination each time.

[0067] Furthermore, the lens appearance inspection device 1 is characterized in that the control unit 100 performs image inspection based on a learned model corresponding to each of the first inspection unit 30A, the second inspection unit 30B, and the third inspection unit 30C. Such a lens appearance inspection device 1 can accurately detect defects in the lens 2 by inspecting the inspection images captured by each inspection unit 30 using an appropriate learned model based on the inspection content.

[0068] Furthermore, the lens appearance inspection device 1 is characterized in that the control unit 100 changes parameters, including at least the illumination intensity and the position of the lens holder 40, according to the type of lens 2 to be inspected. Since such a lens appearance inspection device 1 can take images under appropriate conditions according to the type of lens 2, it can efficiently and accurately detect defects in each lens 2.

[0069] Furthermore, the lens appearance inspection device 1 is characterized in that the illumination light irradiated by the first inspection unit 30A is irradiated with a specific pattern. By irradiating the lens appearance inspection device 1 with illumination light in a pattern that easily highlights defects in the lens 2, such as a striped pattern or multiple circular patterns, the detection of defects in the lens 2 in the captured image can be improved.

[0070] The specific configuration of the present invention is not limited to the embodiments described above, and any design changes or other modifications that do not depart from the spirit of the invention are also included in the present invention.

[0071] 1: Lens appearance inspection device, 2: Lens, 10: Lens loading section, 11: Mounting table, 12: Standing table, 13: Washing section, 14: Holder moving machine, 15: Gripping section, 16: Operation section, 20: Lens holder transport section, 21: Holder chuck, 22: Chuck rail, 23: Moving plate, 24: Conveyor, 25: Temporary gripping section, 25A: Gripping arm, 25B: Gripping section rail, 26: Transport tray, 27: Tray rail, 30: Inspection section, 30A: First inspection section, 30B: Second inspection section, 30C: Third inspection section, 31: Entrance / exit, 32, 32A, 32B, 32C: Holder gripping section, 321A, 321B, 321C: Gripping machine, 322: Holder gripping arm, 323: Protrusion, 324A, 324B, 324C: Support body, 33: Diffusion prevention part, 34A, 34B, 34C: Imaging part, 35: Lower illumination part, 36: Ring illumination part, 37: Coaxial illumination part, 38: Dome illumination part, 39A, 39B, 39C: Lifting rail, 341A, 341B, 341C: Camera body, 342A, 342B, 342C: Camera lens, 361: Irradiation unit, 362: Irradiation support plate, 363: Lifting mechanism, 371: Illumination device, 372: Half mirror, 373: Hole, 40: Lens holder, 41: Holder body, 42: Holding arm, 43: Arm lever, 44: Handle part, 45: Handling recess, 411: Arm hole, 421: Arm part, 422: Holding part, 423: Flange part, A, B: Arrows, S1: Placement space

Claims

1. A lens appearance inspection apparatus comprising: a first inspection unit that captures an image including the lens to be inspected using transmitted illumination; a second inspection unit that captures an image including the lens to be inspected using side illumination; a third inspection unit that captures an image including the lens to be inspected using coaxial incident illumination and dome illumination; and a control unit that detects defects in the lens to be inspected based on the images captured by each unit, wherein the lens to be inspected is transported to the first inspection unit, the second inspection unit, and the third inspection unit while being held in a lens holder, and the lens to be inspected can be imaged by changing the angle of the lens holder.

2. The lens appearance inspection apparatus according to claim 1, characterized in that the control unit performs image inspection based on a learned model corresponding to each of the first inspection unit, the second inspection unit, and the third inspection unit.

3. The lens appearance inspection apparatus according to claim 1 or 2, characterized in that the control unit changes parameters including at least the intensity of illumination and the position of the lens holder according to the type of lens to be inspected.

4. The lens appearance inspection apparatus according to claim 1, characterized in that the illumination light irradiated in the first inspection section is irradiated in a specific pattern.

Images