Inspection system, inspection method, and inspection program

Abstract

To provide an image for revealing an appearance defect in inspection of appearance of a λ / 4 wavelength member.SOLUTION: An inspection system for inspecting appearance of a λ / 4 wavelength member includes: a light emitting section for emitting light; a light reception section for receiving light that is emitted from the light emitting section, arrives at the λ / 4 wavelength member via a polarization member at an angle of 45° or 135° to a polarization angle relative to a slow axis of the λ / 4 wavelength member, and is transmitted through the λ / 4 wavelength member, and is separated in directions of 0° and 90° relative to the polarization angle of the polarization member; and an image generation section for calculating s1 composing a Stokes parameter by using a reception signal outputted from the light reception section, and generating an image on the basis of s1 composing the calculated Stokes parameter.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to an inspection system, an inspection method, and an inspection program. [Background technology]

[0002] Currently, so-called "λ / 4 wavelength components" such as λ / 4 wave plates or λ / 4 wave films used to prevent external light reflection in organic EL (Electro Luminescence) displays and the like are subject to visual appearance inspection by inspectors on sampled components during the manufacturing process.

[0003] To address this issue, it is necessary to perform visual inspections of all components and their entire surface area to ensure quality. However, in the case of transparent components such as λ / 4 wavelength components, it is not easy to detect visual defects, and processing such as analyzing the polarization state of transmitted light is required. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-116294 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-263593 Summary of the Invention [Problem to be solved by the invention]

[0005] On the other hand, the polarization state that makes it easy to detect visual defects differs for each inspection object, and in order to detect visual defects that occur in the manufacturing process of λ / 4 wavelength components, it is desirable to use a polarization state that is suitable for the visual defect of the component. Furthermore, the types of visual defects that occur in the manufacturing process of λ / 4 wavelength components vary (size, shape, pattern, etc.), and it is desirable to provide an image that clearly shows the type of visual defect so that it can be recognized during visual inspection.

[0006] In one aspect, an object of the present invention is to provide an image that makes visible appearance defects in the appearance inspection of a λ / 4 wavelength member. [Means for solving the problem]

[0007] According to one aspect, the inspection system comprises: An inspection system for inspecting the appearance of a λ / 4 wavelength member, a light emitting portion that emits light; a light receiving unit that receives light that is emitted from the light emitting unit, reaches the λ / 4 wavelength member via a polarizing member that forms an angle of 45° or 135° with respect to the polarization angle with respect to the slow axis of the λ / 4 wavelength member, and is transmitted through the λ / 4 wavelength member, and is separated into a direction of 0° and a direction of 90° with respect to the polarization angle of the polarizing member; an image generating unit that calculates s1 constituting a Stokes parameter using a light receiving signal output from the light receiving unit, and generates an image based on s1 constituting the calculated Stokes parameter; 、 With death, The wavelength of the light emitted by the light emitting portion is a wavelength at which the phase angle of the light transmitted through the λ / 4 wavelength member is shifted from 90° by an angle range of at least 5° to 15°. . [Effects of the Invention]

[0008] In the visual inspection of λ / 4 wavelength members, it is possible to provide images that make visual defects obvious. [Brief explanation of the drawings]

[0009] [Figure 1A] FIG. 1 is a first diagram showing an example of a system for examining a configuration for making visible defects in a λ / 4 wavelength member; [Figure 1B] FIG. 2 is a second diagram showing an example of a system for examining a configuration for making visible defects in a λ / 4 wavelength member; [Figure 2A] FIG. 10 is a first diagram showing the results of a study on a process for making visible appearance defects. [Figure 2B] FIG. 10 is a second diagram showing the results of a study on the manifestation process for the appearance defect. [Figure 3]1 is a diagram illustrating an example of a system configuration of an inspection system according to a first embodiment. [Figure 4] FIG. 2 illustrates an example of a hardware configuration of an image generating apparatus. [Figure 5] FIG. 2 is a diagram illustrating an example of a functional configuration of an image generating apparatus. [Figure 6] FIG. 10 is a diagram showing details of the S1′ image generation process by the image generation device. [Figure 7] 10A and 10B are diagrams illustrating details of sensitivity correction processing performed by the image generating device. [Figure 8] 4 is a flowchart showing the flow of an inspection process by the inspection system according to the first embodiment. [Figure 9] FIG. 10 is a diagram illustrating an example of a system configuration of an inspection system according to a second embodiment. [Figure 10] FIG. 10 is a third diagram showing an example of a system for examining a configuration for making visible defects in a λ / 4 wavelength member. [Figure 11] FIG. 10 is a third diagram showing the results of a study on the manifestation process for the appearance defect. [Figure 12] 10 is a flowchart showing the flow of an inspection process by an inspection system according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, each embodiment will be described with reference to the accompanying drawings. In this specification and drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant description will be omitted.

[0011] [First embodiment] <Overview of inspection subjects> First, an overview of λ / 4 wavelength components, which are the object of inspection by the inspection system according to the first embodiment, will be described. λ / 4 wavelength components are components used to prevent reflection of external light in organic EL displays and the like, and include both λ / 4 wavelength films and λ / 4 wavelength plates. When a portion of a λ / 4 wavelength component is thinner than the other portions, the phase difference of light passing through that portion shifts from the phase difference of light passing through the other portions, and this is recognized as a defective appearance. Note that λ / 4 here does not strictly refer to 90°, but refers to an angle range of approximately 90°±15°.

[0012] There are several factors that can cause some areas to be thinner than other areas during the manufacturing process of a λ / 4 wavelength component, and in this embodiment, the types of appearance defects for each factor are referred to as "spot unevenness," "coating streaks," "horizontal unevenness," and "flow direction streaks."

[0013] The λ / 4 wavelength component to be inspected may or may not have a polarizing component laminated thereon during the visual inspection. The polarizing component here includes both polarizing films and polarizing plates.

[0014] In the first embodiment, a case where a λ / 4 wavelength member without a laminated polarizing member is to be inspected will be described. However, in the following, when considering a configuration for making appearance defects apparent, we will consider the optimal polarization state that can make appearance defects apparent in any case of the inspection target.

[0015] <System under consideration> A system for examining the optimal polarization state that can reveal visual defects of a λ / 4 wavelength component will be described. As described above, visual defects of a λ / 4 wavelength component are caused by a shift in the phase difference of light that passes through a certain region. The shift in the phase difference of light can be revealed in the polarization state. Therefore, in examining the optimal polarization state, the applicant of the present application focused on the Stokes parameters, which can express various polarization states.

[0016] The Stokes parameters consist of four types of parameters, s0 to s3, and when calculating each parameter, 0° linearly polarized signal, 45° linearly polarized signal, 90° linearly polarized signal, 135° linearly polarized signal, Right-handed circularly polarized signal, Left-handed circularly polarized signal, is used.

[0017] 1A and 1B are first and second diagrams showing an example of a system for examining a configuration that makes appearance defects of a λ / 4 wavelength member apparent, and show a system for acquiring each polarization signal used when calculating the above parameters.

[0018] 1A shows an example of a system for receiving a 0° linearly polarized signal and a 90° linearly polarized signal, which are used to calculate parameters s0 and s1. As shown in FIG. 1A, light emitted from a light emitting unit 110 reaches a λ / 4 wavelength member 130 via a polarizing member 120, and is then received by a light receiving unit 150 after passing through a λ / 4 wavelength member 140.

[0019] As described above, in the first embodiment, the inspection target is a λ / 4 wavelength component on which no polarizing component is stacked. However, in order to consider an optimal polarization state that can be applied even when the inspection target is a λ / 4 wavelength component on which a polarizing component is stacked, the system is configured so that light reaches the λ / 4 wavelength component 130 via the polarizing component 120.

[0020] As indicated by arrow 121, the polarization angle of the polarizing member 120 is 45° or 135° with respect to the slow axis (arrow 131) of the λ / 4 wavelength member 130. This is to achieve the same relationship as the relationship between the slow angle of the λ / 4 wavelength member on which the polarizing member is stacked and the polarization angle of the polarizing member.

[0021] 1A, an arrow 141 indicates the slow axis of the λ / 4 wavelength member 140. As shown in FIG. 1A, the slow axis of the λ / 4 wavelength member 140 is at 0°.

[0022] The light receiving unit 150 is a polarization camera. As indicated by the reference numeral 151, each pixel of the light receiving unit 150 has an area 152 for receiving a 0° linearly polarized signal and an area 154 for receiving a 90° linearly polarized signal.

[0023] As a result, according to the light receiving unit 150 of FIG. 1A, ·Image based on 0° linear polarization signal (0° polarization image), -Images based on 90° linearly polarized signals (90° polarized images), can be output.

[0024] 1B shows an example of a system for receiving a 45° linearly polarized signal, a 135° linearly polarized signal, a right-handed circularly polarized signal, and a left-handed circularly polarized signal, which are used to calculate parameters s2 and s3. As shown in FIG. 1B, light emitted from light emitting unit 110 reaches λ / 4 wavelength member 130 via polarizing member 120, and is then received by light receiving unit 150 after passing through λ / 4 wavelength member 160.

[0025] As indicated by arrow 121, the polarization angle of the polarizing member 120 is 45° or 135° with respect to the slow axis (arrow 131) of the λ / 4 wavelength member 130. Also, as indicated by arrow 161, the slow axis of the λ / 4 wavelength member 160 is 45°.

[0026] The light receiving unit 150 is a polarization camera. As indicated by the reference numeral 151, each pixel of the light receiving unit 150 has an area 153 for receiving a 45° linearly polarized signal, an area 155 for receiving a 135° linearly polarized signal, an area 152 for receiving a right-handed circularly polarized signal, and an area 154 for receiving a left-handed circularly polarized signal.

[0027] As a result, according to the light receiving unit 150 of FIG. 1B, ·Images based on 45° linearly polarized signals (45° polarized images), ·Image based on 135° linearly polarized signal (135° polarized image), · Images based on right-handed circularly polarized signals (right-handed circularly polarized images), Left-handed circularly polarized image based on left-handed circularly polarized signal (left-handed circularly polarized image), can be output.

[0028] <Polarization state study results> Next, the optimal polarization state is examined based on each image generated using the above system. The above system calculates Stokes parameters using each image output from the light receiving unit 150, thereby generating an image corresponding to each parameter. Therefore, by comparing the images corresponding to each generated parameter, it is possible to identify the optimal polarization state that can reveal visual defects contained in the λ / 4 wavelength member 130 being inspected. Figure 2A is a first diagram showing the results of an examination of the process of revealing visual defects.

[0029] As shown in Figure 2A, when generating an image corresponding to each parameter, the normalized Stokes parameters S' are calculated. The normalized Stokes parameters S' are composed of four types of parameters, s0, s1', s2', and s3', of which s1', s2', and s3' are respectively ·s1'=s1 / s0, ·s2'=s2 / s0, ·s3'=s3 / s0, It is calculated as follows.

[0030] Parameter s0 is light intensity, and the image generated by calculating parameter s0 is generated by adding a 0° polarized image and a 90° polarized image, as shown in FIG. 2A. The image generated by calculating parameter s1 is generated by subtracting a 0° polarized image and a 90° polarized image, as shown in FIG. 2A. The image generated by calculating parameter s2 is generated by subtracting a 45° polarized image and a 135° polarized image, as shown in FIG. 2A. The image generated by calculating parameter s3 is generated by subtracting a right-handed circularly polarized image and a left-handed circularly polarized image, as shown in FIG. 2A.

[0031] In FIG. 2A, reference numerals 201 to 204 denote images corresponding to the respective parameters generated by calculating the normalized Stokes parameter S' for the λ / 4 wavelength member 130 containing spot unevenness.

[0032] Of these, Reference numeral 201 denotes an image (S0 image) generated by calculating the parameter s0; Reference numeral 202 denotes an image (S1′ image) generated by calculating the parameter s1′; Reference numeral 203 denotes an image (S2′ image) generated by calculating the parameter s2′; Reference numeral 204 denotes an image (S3′ image) generated by calculating the parameter s3′; are shown respectively.

[0033] In FIG. 2A, reference numerals 211 to 214 denote images corresponding to the respective parameters generated by calculating the normalized Stokes parameter S' for the λ / 4 wavelength member 130 containing horizontal step unevenness.

[0034] Of these, Reference numeral 211 denotes an image (S0 image) generated by calculating the parameter s0; Reference numeral 212 denotes an image (S1′ image) generated by calculating the parameter s1′; Reference numeral 213 denotes an image (S2′ image) generated by calculating the parameter s2′; Reference numeral 214 denotes an image (S3′ image) generated by calculating the parameter s3′; are shown respectively.

[0035] As is clear from Figure 2A, of the four parameters that make up the Stokes parameters, the image (S1' image) generated by calculating parameter s1' is able to most clearly show spot unevenness and horizontal stripe unevenness, and has high visibility.

[0036] Similar visualization processing was also performed on other appearance defects, resulting in the results shown in Figure 2B. Figure 2B is the second diagram showing the results of the investigation into the visualization processing for appearance defects. As shown in Figure 2B, the image generated by calculating the parameter s1' (S1' image) was able to visualize coating streaks and machine direction streaks most clearly, demonstrating high visibility.

[0037] Therefore, in the inspection system according to the first embodiment, among the Stokes parameters that can express the polarization state, the normalized parameter s1′, which can generate an image with high visibility of appearance defects, is used as the parameter that expresses the optimal polarization state.

[0038] <Inspection system configuration> Next, a system configuration of an inspection system according to a first embodiment, which performs visual inspection under the above-described optimal polarization state, will be described. Fig. 3 is a diagram showing an example of the system configuration of the inspection system according to the first embodiment.

[0039] As shown in Fig. 3, the inspection system 300 according to the first embodiment includes a light emitting unit 310, a polarizing member 320, a light receiving unit 330, an image generating device 340, and a display device 350. The inspection target of the inspection system 300 according to the first embodiment is a λ / 4 wavelength member 360 on which no polarizing member is laminated, and is a long member conveyed in a conveying direction 371 by a conveying unit (not shown). The long member referred to here includes a long film. The slow axis (reference symbol 361) of the λ / 4 wavelength member 360 is shifted by 45° or 135° with respect to the conveying direction 371.

[0040] The light emitting unit 310 is disposed below the transport path of the λ / 4 wavelength member 360, and emits light to the λ / 4 wavelength member 360 transported by the transport unit to an upper inspection position.

[0041] The polarizing member 320 is disposed between the inspection position in the transport path of the λ / 4 wavelength member 360 and the light emitting unit 310. As a result, the light emitted by the light emitting unit 310 reaches the λ / 4 wavelength member 360 via the polarizing member 320. The polarizing member 320 is a polarizing member in which the angle formed by the polarization angle (reference symbol 321) with respect to the slow axis (reference symbol 361) of the λ / 4 wavelength member is 45° or 135°.

[0042] Light receiving unit 330 receives light that has passed through λ / 4 wavelength member 360 at the inspection position. Light receiving unit 330 has a prism spectrometer 331, which splits the light that has passed through the λ / 4 wavelength member into a 0° direction and a 90° direction with respect to the polarization angle (reference numeral 321) of polarizing member 320. The light that has been split into the 0° direction is received by polarization line camera 332, which generates a 0° polarized image. Meanwhile, the light that has been split into the 90° direction is received by polarization line camera 333, which generates a 90° polarized image.

[0043] The 0° direction in which light is separated relative to the polarization angle (reference symbol 321) of the polarizing member 320 is parallel to the conveying direction 371 when the conveying unit conveys the λ / 4 wavelength member, which is a long member. The 90° direction in which light is separated relative to the polarization angle (reference symbol 321) of the polarizing member 320 is perpendicular to the conveying direction 371 when the conveying unit conveys the λ / 4 wavelength member, which is a long member.

[0044] The 0° polarized image generated by the polarized line camera 332 and the 90° polarized image generated by the polarized line camera 333 are sent to the image generating device 340 .

[0045] The image generating device 340 calculates the parameter s1' based on the 0° polarized image and the 90° polarized image transmitted from the light receiving unit 330, thereby generating an image that makes visible the appearance defects contained in the λ / 4 wavelength member 360. The image generating device 340 displays the image that makes visible the appearance defects on the display device 350.

[0046] <Hardware configuration of image generation device> Next, the hardware configuration of the image generation device 340 will be described. Fig. 4 is a diagram showing an example of the hardware configuration of the image generation device. As shown in Fig. 4, the image generation device 340 has a processor 401, a memory 402, an auxiliary storage device 403, an I / F (Interface) device 404, a communication device 405, and a drive device 406. Note that the respective hardware components of the image generation device 340 are connected to each other via a bus 407.

[0047] The processor 401 has various arithmetic devices such as a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), etc. The processor 401 reads various programs (for example, an inspection program, etc.) into the memory 402 and executes them.

[0048] The memory 402 has a main storage device such as a ROM (Read Only Memory), a RAM (Random Access Memory), etc. The processor 401 and the memory 402 form a so-called computer, and the processor 401 executes various programs read onto the memory 402, thereby enabling the computer to realize various functions.

[0049] The auxiliary storage device 403 stores various programs and various data used when the processor 401 executes the various programs.

[0050] The I / F device 404 is a device for connecting the display device 350 and the operation device 410 with the image generation device 340. The I / F device 404 accepts operations of the inspector 351 on the image generation device 340 via the operation device 410. The I / F device 404 also outputs images etc. generated by the image generation device 340 and displays them to the inspector 351 via the display device 350.

[0051] The communication unit 405 is a communication device for communicating with other devices (for example, the light receiving unit 330, etc.) via a network (not shown).

[0052] The drive device 406 is a device for loading a recording medium 420. The recording medium 420 here includes media that record information optically, electrically, or magnetically, such as a CD-ROM, a flexible disk, or a magneto-optical disk. The recording medium 420 may also include semiconductor memory that records information electrically, such as a ROM or flash memory.

[0053] The various programs to be installed in the auxiliary storage device 403 are installed, for example, by setting the distributed recording medium 420 in the drive device 406 and reading the various programs recorded on the recording medium 420 by the drive device 406. Alternatively, the various programs to be installed in the auxiliary storage device 403 may be installed by being downloaded from a network (not shown) via the communication device 405.

[0054] <Functional configuration of the image generation device> Next, the functional configuration of the image generating device 340 will be described. Fig. 5 is a diagram showing an example of the functional configuration of the image generating device. As described above, an inspection program is installed in the image generating device 340, and by executing this program, the image generating device 340 functions as a 0° polarized image acquiring unit 501 and a 90° polarized image acquiring unit 502. The image generating device 340 also functions as an S0 image generating unit 503, an S1 image generating unit 504, an S1' image generating unit 505, an S1'' image generating unit 506, a detection processing unit 507, and a display control unit 508.

[0055] The 0° polarized image acquisition unit 501 acquires the 0° polarized image transmitted from the polarization line camera 332. The 0° polarized image acquisition unit 501 notifies the S0 image generation unit 503 and the S1 image generation unit 504 of the acquired 0° polarized image.

[0056] The 90° polarized image acquisition unit 502 acquires the 90° polarized image transmitted from the polarization line camera 333. The 90° polarized image acquisition unit 502 notifies the S0 image generation unit 503 and the S1 image generation unit 504 of the acquired 90° polarized image.

[0057] The S0 image generation unit 503 generates an S0 image by adding the 0° polarized image notified from the 0° polarized image acquisition unit 501 and the 90° polarized image notified from the 90° polarized image acquisition unit 502. The S0 image generation unit 503 notifies the S1′ image generation unit 505 of the generated S0 image.

[0058] The S1 image generation unit 504 generates an S1 image by calculating the difference between the 0° polarized image notified from the 0° polarized image acquisition unit 501 and the 90° polarized image notified from the 90° polarized image acquisition unit 502. The S1 image generation unit 504 notifies the S1′ image generation unit 505 of the generated S1 image.

[0059] The S1' image generation unit 505 generates the S1' image by dividing the S1 image notified from the S1 image generation unit 504 by the S0 image notified from the S0 image generation unit 503. Here, it is assumed that the S1' image generated by the S1' image generation unit 505 is an S1' image generated based on a 0° linearly polarized signal and a 90° linearly polarized signal received in the absence of the λ / 4 wavelength member 360 and the polarizing member 320. In this case, the S1' image generation unit 505 stores the S1' image in the correction image storage unit 510 as a correction image.

[0060] The S1' image generated based on the 0° linearly polarized signal and the 90° linearly polarized signal received without the λ / 4 wavelength member 360 and the polarizing member 320 is an image resulting from the difference in sensitivity between the polarization line camera 332 and the polarization line camera 333, and is therefore noise. Therefore, as described above, the S1' image generating unit 505 stores the S1' image generated based on the 0° linearly polarized signal and the 90° linearly polarized signal received without the λ / 4 wavelength member 360 and the polarizing member 320 in the correction image storage unit 510 as a correction image.

[0061] On the other hand, suppose that the S1' image generated by the S1' image generation unit 505 is an S1' image generated based on a 0° linearly polarized signal and a 90° linearly polarized signal received in the presence of the λ / 4 wavelength member 360 and the polarizing member 320. In this case, the S1' image generation unit 505 notifies the S1'' image generation unit 506 of the generated S1' image.

[0062] The S1" image generation unit 506 removes noise from the S1' image by subtracting the correction image stored in the correction image storage unit 510 from the S1' image notified by the S1' image generation unit 505. In this way, the S1" image generation unit 506 corrects the difference in sensitivity between the polarization line camera 332 and the polarization line camera 333, and generates an S1" image, which is the corrected S1' image. The S1" image generation unit 506 notifies the detection processing unit 507 and display control unit 508 of the generated S1" image.

[0063] The detection processing unit 507 performs visual defect detection processing on the S1'' image notified from the S1'' image generation unit 506, and detects visual defects contained in the λ / 4 wavelength member 360 that is the inspection target. Note that the visual defect detection processing referred to here may be, for example, processing to detect an area equal to or greater than a predetermined threshold as a visual defect, or processing to detect an area that is equal to or greater than a predetermined threshold and whose size and shape satisfy predetermined conditions as a visual defect.

[0064] The detection processing unit 507 also generates a rectangle circumscribing the detected area (area containing a visual defect) and extracts an S1'' image (rectangular area image) of the area contained in the rectangle. The detection processing unit 507 notifies the display control unit 508 of the generated rectangle and the extracted rectangular area image.

[0065] The display control unit 508 displays the S1'' image notified from the S1'' image generation unit 506 on the display device 350. Furthermore, when instructed by the inspector 351, the display control unit 508 superimposes the rectangle notified from the detection processing unit 507 on the S1'' image and displays it on the display device 350. Furthermore, when instructed by the inspector 351, the display control unit 508 enlarges and displays the rectangular area image notified from the detection processing unit 507 in a display area different from the display area displaying the S1'' image.

[0066] <Details of processing by the image generation device> Next, a detailed description will be given of the processing performed by each unit of the image generating device 340. Here, a detailed description will be given of the S1′ image generating process performed by the S1′ image generating unit 505 and the sensitivity correction process performed by the S1″ image generating unit 506.

[0067] (1) Details of S1' image generation process First, we will explain the details of the S1' image generation process by the S1' image generation unit 505. Fig. 6 is a diagram showing the details of the S1' image generation process by the image generation device. As shown in Fig. 6, the S1' image generation unit 505 has an S1 / S0 calculation unit 601.

[0068] The S1 / S0 calculation unit 601 generates an S1' image by dividing the S1 image notified from the S1 image generation unit 504 by the S0 image notified from the S0 image generation unit 503. Here, it is assumed that the S1' image generated by the S1 / S0 calculation unit 601 is an S1' image generated based on a 0° linear polarization signal and a 90° linear polarization signal received in the absence of the λ / 4 wavelength member 360 and the polarizing member 320. In this case, the S1 / S0 calculation unit 601 stores the S1' image in the correction image storage unit 510 as a correction image.

[0069] On the other hand, suppose that the S1' image generated by the S1 / S0 calculation unit 601 is an S1' image generated based on the 0° linear polarization signal and the 90° linear polarization signal received in the presence of the λ / 4 wavelength member 360 and the polarizing member 320. In this case, the S1 / S0 calculation unit 601 notifies the S1'' image generation unit 506 of the generated S1' image.

[0070] (2) Details of sensitivity correction process Next, the sensitivity correction process performed by the S1" image generation unit 506 will be described in detail. FIG. 7 is a diagram showing the details of the sensitivity correction process performed by the image generation device. As shown in FIG. 7, the S1" image generation unit 506 includes a difference calculation unit 701, an average value calculation unit 702, an image brightness calculation unit 703, and an adjustment unit 704.

[0071] As described above, the S1'' image generating unit 506 is notified by the S1 / S0 calculating unit 601 of the S1' image generated based on the 0° linear polarization signal and the 90° linear polarization signal received in the presence of the λ / 4 wavelength member 360 and the polarizing member 320.

[0072] In addition, the correction image storage unit 510 stores, as a correction image, an S1' image generated based on the 0° linear polarization signal and the 90° linear polarization signal received without the λ / 4 wavelength member 360 and the polarizing member 320.

[0073] Difference calculation unit 701 removes noise from the S1' image by subtracting the correction image stored in correction image storage unit 510 from the S1' image notified by S1' image generation unit 505. In this way, difference calculation unit 701 corrects the sensitivity difference between polarization line camera 332 and polarization line camera 333, and generates a corrected S1' image.

[0074] The difference calculation unit 701 notifies the average value calculation unit 702 and the image brightness calculation unit 703 of the corrected S1′ image.

[0075] The average value calculation unit 702 calculates the average brightness value of a 200 pixel x 200 pixel area including the center position of the corrected S1' image. The average value calculation unit 602 notifies the image brightness calculation unit 703 of the calculated average brightness value.

[0076] The image luminance calculation unit 703 calculates the difference from the average luminance value by subtracting the average luminance value from the luminance value of each pixel in the corrected S1' image. Furthermore, to convert the luminance value of each pixel to 10 bits (1024 gradations), the image luminance calculation unit 703 multiplies the calculated difference from the average luminance value by a value obtained by dividing 1024 gradations by the display range of the display device 350. Furthermore, the image luminance calculation unit 703 adds a predetermined offset value to the luminance value after multiplication. In other words, the image luminance calculation unit 703 converts the luminance value of each pixel in the corrected S1' image to 1024 gradations based on the following formula, and calculates the converted luminance value: (Brightness value after conversion)=(brightness value of S1' image after correction-average brightness value)×1024 / (display range of display device 350)+offset value In the above formula, for example, "0.08" is set as the display range of the display device 350. Also, in the above formula, for example, "511" is set as the offset value.

[0077] The image luminance calculation unit 703 notifies the adjustment unit 704 of the image for which the converted luminance values ​​have been calculated.

[0078] If the luminance values ​​of the pixels included in the image for which the post-conversion luminance values ​​have been calculated and notified by the image luminance calculation unit 703 include a luminance value exceeding 1023, the adjustment unit 704 adjusts the luminance value of the pixel to 1023. Furthermore, if the luminance values ​​of the pixels included in the image for which the post-conversion luminance values ​​have been calculated and notified by the image luminance calculation unit 703 include a luminance value less than 0, the adjustment unit 704 adjusts the luminance value of the pixel to 0.

[0079] Furthermore, the adjustment unit 704 notifies the detection processing unit 507 and the display control unit 508 of the image after the adjustment of the brightness value as the S1″ image. If the display device 350 is an 8-bit device, the adjustment unit 704 further converts the S1″ image from 10 bits to 8 bits before notifying the display control unit 508. The adjustment unit 704 converts the brightness value of each pixel included in the S1″ image from 10 bits to 8 bits by dividing the brightness value of each pixel included in the S1″ image by 4.

[0080] <Inspection processing flow by the inspection system> Next, a description will be given of the flow of the inspection process by the inspection system 300 according to the first embodiment. Fig. 8 is a flowchart showing the flow of the inspection process by the inspection system according to the first embodiment.

[0081] In step S801, the image generating device 340 sets the display range and offset value of the display device 350 to be used in the S1' image generating process.

[0082] In step S802, the image generating device 340 generates an S1' image based on the 0° linear polarization signal and the 90° linear polarization signal received without the λ / 4 wavelength element 360 and the polarizing element 320, and stores the S1' image in the correction image storage unit 510 as a correction image.

[0083] In step S803, the inspector 351 sets the λ / 4 wavelength member 360 to be inspected.

[0084] In step S804, the inspector 351 instructs the start of transportation of the λ / 4 wavelength member 360 to be inspected, and also instructs the start of processing by the image generating device 340. This causes transportation of the λ / 4 wavelength member 360 to be inspected to start. Furthermore, processing by the image generating device 340 starts, and the S1'' image is displayed on the display device 350.

[0085] In step S805, the image generating device 340 determines whether or not a visual defect has been detected in the inspected λ / 4 wavelength member 360. If it is determined in step S805 that a visual defect has not been detected (NO in step S805), the process proceeds to step S807.

[0086] On the other hand, if it is determined in step S805 that a visual defect has been detected (YES in step S805), the process proceeds to step S806.

[0087] In step S806, the image generating device 340 displays an S1'' image in which a rectangle is superimposed on the area containing the visual defect, and also displays an enlarged image of the rectangular area, thereby notifying the inspector 351 of the visual defect.

[0088] In step S807, the image generating device 340 performs a visual inspection on the entire area of ​​the λ / 4 wavelength member 360 to be inspected, and determines whether the transport process is complete. If it is determined in step S807 that there is an area for which the visual inspection has not been performed (NO in step S807), the process returns to step S805.

[0089] On the other hand, in step S807, if it is determined that the appearance inspection has been performed on the entire area of ​​the λ / 4 wavelength member 360 to be inspected and the transport process has ended (YES in step S807), the process proceeds to step S808.

[0090] In step S808, inspector 351 determines whether or not to end the visual inspection. If it is determined in step S808 that the visual inspection is to be continued (NO in step S808), the process returns to step S802.

[0091] On the other hand, if it is determined in step S808 that the visual inspection is to be ended (YES in step S808), inspector 351 instructs image generation device 340 to end the processing. As a result, image generation device 340 ends the processing, and inspection processing by inspection system 300 ends.

[0092] <Summary> As is clear from the above description, the inspection system 300 according to the first embodiment: The light emitting portion 310 is provided for emitting light. The optical fiber 300 includes a light receiving unit 330 that receives light. The light emitted by the light emitting unit 310 reaches the λ / 4 wavelength member 360 via a polarizing member 320, which forms an angle of 45° or 135° with the polarization angle relative to the slow axis of the λ / 4 wavelength member 360. The light that has passed through the λ / 4 wavelength member 360 is received by the light receiving unit 330. The light receiving unit 330 is configured to receive light that has been split into directions of 0° and 90° with respect to the polarization angle of the polarizing member 320. The image generating device 340 calculates s1, which constitutes the Stokes parameter, using the received light signals (0° linear polarization signal, 90° linear polarization signal) output from the light receiving unit 330, and generates an S1″ image based on the calculated s1.

[0093] In this way, the inspection system 300 according to the first embodiment generates an image under an optimal polarization state that can generate an image with high visibility and makes visible any visual defects contained in the λ / 4 wavelength member 360. As a result, the inspection system 300 according to the first embodiment can provide an image that makes visible any visual defects in the visual inspection of the λ / 4 wavelength member 360.

[0094] [Second embodiment] In the first embodiment, Fig. 3 shows an inspection system 300 for a case where a polarizing member is not laminated on a λ / 4 wavelength member to be inspected. In contrast, in the second embodiment, an inspection system for a case where a polarizing member is laminated on a λ / 4 wavelength member to be inspected will be described. The second embodiment will be described below, focusing on the differences from the first embodiment.

[0095] Fig. 9 is a diagram showing an example of the system configuration of an inspection system according to the second embodiment. The difference from the inspection system 300 shown in Fig. 3 is that the inspection system 900 shown in Fig. 9 does not include a polarizing member 320. Also, in the inspection system 900 shown in Fig. 9, a polarizing member 910 is stacked on the λ / 4 wavelength member 360 to be inspected.

[0096] 9, the polarizing member 910 is laminated on one surface of the λ / 4 wavelength member 360. The λ / 4 wavelength member 360 is transported so that the surface on which the polarizing member 910 is laminated faces downward (facing the light emitting unit 310).

[0097] The polarizing element 910 is stacked on the λ / 4 wavelength element 360 so that the angle between the polarization angle and the slow axis (symbol 361) of the λ / 4 wavelength element is 45° or 135° (i.e., parallel to the conveying direction 371).

[0098] As a result, the light emitted by the light emitting unit 310 reaches the λ / 4 wavelength member 360 via the polarizing member 910, and the light transmitted through the λ / 4 wavelength member 360 is received by the light receiving unit 330. The configuration after the light receiving unit 330 is the same as that of the inspection system 300 described in the first embodiment.

[0099] In this way, the inspection system 900 according to the second embodiment can generate an image under an optimal polarization state that can reveal defects in appearance and generate an image with high visibility, even when the polarizing element 910 is stacked on the λ / 4 wavelength element 360 to be inspected.

[0100] As a result, the inspection system 900 according to the second embodiment can provide an image that makes visible any defects in appearance during the appearance inspection of the λ / 4 wavelength member 360, similar to the first embodiment.

[0101] [Third embodiment] In the first embodiment, an optimum polarization state capable of generating a highly visible image by making visible defects contained in the λ / 4 wavelength member 360 is considered. In contrast, in the third embodiment, an optimum wavelength of light (the wavelength of light emitted from the light emitting portion) capable of generating a highly visible image by making visible defects contained in the λ / 4 wavelength member 360 is considered.

[0102] <System under consideration> First, a system for examining the optimum wavelength of light that can reveal defects in the appearance of a λ / 4 wavelength member will be described. In the first embodiment, the wavelength of the light emitted by the light emitting unit is not mentioned, but the wavelength of the light emitted by the light emitting unit is also important in revealing defects in the appearance of the λ / 4 wavelength member 360.

[0103] Fig. 10 is a third diagram showing an example of a system for examining a configuration for making a visual defect of a λ / 4 wavelength member apparent. The example of Fig. 10 shows an example of a system that includes three types of light emitting units, light emitting unit 1010, light emitting unit 1020, and light emitting unit 1030, and generates S1' images when light is sequentially emitted from each light emitting unit to a λ / 4 wavelength member 130 that has a visual defect.

[0104] The light emitted from the light emitting unit 1010 is · Red light with wavelength = 635 [nm], Phase difference of the λ / 4 wavelength member 130=152 [nm], Phase angle of light transmitted through the λ / 4 wavelength member 130=86.2° Furthermore, the light emitted from the light emitting unit 1020 is expressed as follows: Green light with a wavelength of 515 nm Phase difference of the λ / 4 wavelength member 130=143 [nm], Phase angle of light transmitted through the λ / 4 wavelength member 130=100.0° Furthermore, the light emitted from the light emitting portion 1030 is Wavelength = 465 [nm] blue light, Phase difference of the λ / 4 wavelength member 130=128 [nm], Phase angle of light transmitted through the λ / 4 wavelength member 130=99.1° is.

[0105] <Results of light wavelength study> Next, the optimum wavelength of light is considered based on each image generated using the above system. Specifically, by comparing each S1' image generated based on the light emitted from each light emitting unit, the optimum wavelength of light that can reveal the appearance defects contained in the λ / 4 wavelength member 130 to be inspected is considered.

[0106] Fig. 11 is a third diagram showing the results of a study on the processing for making visible appearance defects. In Fig. 11, reference numerals 1101 to 1103 denote S1' images generated based on light emitted from light emitting portion 1010 to light emitted from light emitting portion 1030 for a λ / 4 wavelength member 130 having horizontal unevenness.

[0107] 11, it was found that, of the three types of light output units, the use of light output unit 1020 and light output unit 1030 was able to make appearance defects more obvious and provide higher visibility than the use of light output unit 1010. In other words, it can be said that a light output unit that emits light with a wavelength that is shifted by about 10° from the 90° phase angle at which light transmitted through the λ / 4 wavelength member 130 becomes completely circularly polarized light is able to make appearance defects more obvious and generate an image with high visibility.

[0108] Therefore, in the inspection system 300 or 900 according to the third embodiment, when the phase angle of the light transmitted through the λ / 4 wavelength member 360 is θ, 5°≦|θ-90°|≦15° More preferably, light having a wavelength 7.5°≦|θ-90°|≦12.5° A light emitting section that emits light with a wavelength of

[0109] <Summary> As is clear from the above description, the inspection system 300 or 900 according to the third embodiment: It has a light emitting section that emits light of a wavelength based on the phase angle θ of the light that has passed through the λ / 4 wavelength member (light of a wavelength that satisfies 5°≦|θ−90°|≦15°).

[0110] As a result, the inspection system 300 or 900 according to the third embodiment can more clearly identify any visual defects contained in the λ / 4 wavelength member 360 to be inspected, thereby generating an image with high visibility.

[0111] That is, the inspection system 300 or 900 according to the third embodiment can provide an image in which defects in appearance are more clearly visible in the appearance inspection of the λ / 4 wavelength member 360.

[0112] [Fourth embodiment] In the above embodiments, the λ / 4 wavelength member 360, which is the object of visual inspection by the inspection system 300 or 900, has been described as a long member. However, the λ / 4 wavelength member, which is the object of visual inspection by the inspection system 300 or 900, is not limited to a long member and may be a sheet member. The term "sheet member" as used herein includes sheet films and sheet plates.

[0113] Even when the λ / 4 wavelength member is a sheet member, the relationship between the slow axis of the λ / 4 wavelength member and the polarization angle of the polarizing member, and the relationship between the polarization angle of the polarizing member and the direction of the light separated at the light receiving unit is the same as in the case of a long-shaped member.

[0114] However, when the λ / 4 wavelength member to be inspected is a sheet member, the flow of the inspection process by the inspection system 300 or 900 differs from that for a long member.

[0115] FIG. 12 is a flowchart showing the flow of the inspection process by the inspection system according to the fourth embodiment.

[0116] In step S801, the image generating device 340 sets the display range and offset value of the display device 350 to be used in the S1' image generating process.

[0117] In step S802, the image generating device 340 generates an S1' image based on the 0° linearly polarized signal and the 90° linearly polarized signal received without the λ / 4 wavelength member 360 (and the laminated polarizing member 910). The image generating device 340 also stores the generated S1' image in the correction image storage unit 510 as a correction image.

[0118] In step S1201, the image generating device 340 determines whether there is a λ / 4 wavelength member to be visually inspected next. If it is determined in step S1201 that there is a λ / 4 wavelength member to be visually inspected next (YES in step S1201), the process proceeds to step S1202.

[0119] In step S1202, the transport unit transports one λ / 4 wavelength member 360 to be inspected to the inspection position.

[0120] In step S1203, the image generating device 340 generates the S1'' image. As a result, the S1'' image is displayed on the display device 350.

[0121] In step S1204, the image generating device 340 determines whether or not a visual defect has been detected in the λ / 4 wavelength member being inspected. If it is determined in step S1204 that a visual defect has not been detected (NO in step S1204), the process returns to step S1201.

[0122] On the other hand, if it is determined in step S1204 that a visual defect has been detected (YES in step S1204), the process proceeds to step S1205.

[0123] In step S1205, the image generating device 340 displays an S1'' image in which a rectangle is superimposed on the area containing the visual defect, and also displays an enlarged image of the rectangular area to notify the inspector 351 of the visual defect, and then returns to step S1201.

[0124] Also, in step S1201, if it is determined that there is no λ / 4 wavelength member to be visually inspected next (NO in step S1201), the process proceeds to step S808.

[0125] In step S808, inspector 351 determines whether or not to end the visual inspection. If it is determined in step S808 that the visual inspection is to be continued (NO in step S808), the process returns to step S802.

[0126] On the other hand, if it is determined in step S808 that the visual inspection is to be ended (YES in step S808), inspector 351 instructs image generation device 340 to end the processing. As a result, image generation device 340 ends the processing, and the inspection processing by inspection system 300 or 900 ends.

[0127] <Summary> As is clear from the above description, the inspection system 300 or 900 according to the fourth embodiment: · Visual inspection is performed in the same way not only when the λ / 4 wavelength component to be inspected is a long component, but also when it is a sheet component. When the λ / 4 wavelength component to be inspected is a sheet component, the transport unit is provided to transport the λ / 4 wavelength component to the inspection position, just like a long component.

[0128] In this way, according to the inspection system 300 or 900 of the fourth embodiment, it is possible to make appearance defects apparent and generate highly visible images, regardless of whether the λ / 4 wavelength member being inspected is a long-shaped member or a sheet-like member.

[0129] In other words, according to the inspection system 300 or 900 of the fourth embodiment, when inspecting the appearance of a λ / 4 wavelength member 360, it is possible to provide an image that makes visible any appearance defects, regardless of whether the member is a long-shaped member or a sheet-like member.

[0130] [Other embodiments] In the above embodiments, normalized Stokes parameters are calculated to generate an image that visualizes a visual defect contained in a λ / 4 wavelength member. However, an image may be generated by calculating the Stokes parameters without normalizing them.

[0131] Furthermore, although the above embodiments did not mention the timing of generating a correction image, the timing of generating a correction image may be, for example, the timing when the light receiving unit 330 deteriorates over time or the timing when the light emitting unit 310 deteriorates over time.

[0132] Furthermore, in each of the above embodiments, when the detection processing unit 507 detects a visual defect, the detection result is output by notifying the display control unit 508 and displaying it to the inspector 351. However, the method of outputting the detection result when the detection processing unit 507 detects a visual defect is not limited to this. For example, a CSV file indicating the detection result may be generated and output. Alternatively, the detection result may be notified to a defect information management system, and the defect information management system may mark the inspection target based on the notified detection result.

[0133] In addition, in the above-described embodiments, the case where a polarizing member is not laminated on the λ / 4 wavelength member to be inspected or the case where a polarizing member is laminated on the λ / 4 wavelength member to be inspected has been described. However, the λ / 4 wavelength member to be inspected may be laminated with another member (for example, a base material) that does not affect the front retardation.

[0134] Furthermore, in each of the above embodiments, it has been described that one light receiving unit 330 is installed when performing visual inspection of a λ / 4 wavelength member, but multiple light receiving units 330 may be installed depending on the widthwise length of the λ / 4 wavelength member.

[0135] Furthermore, in each of the above embodiments, the 0° polarized image and the 90° polarized image transmitted from one light receiving unit 330 are described as being processed by one image generating device 340, but a configuration in which multiple image generating devices 340 process the images may also be used.

[0136] The present invention is not limited to the configurations described in the above embodiments, but may be combined with other elements, etc. These aspects can be changed without departing from the spirit of the present invention, and can be appropriately determined depending on the application form. [Explanation of symbols]

[0137] 300: Inspection system 310: Light emitting part 320: Polarizing element 330: Light receiving section 331: Prism spectrometer 332: Polarized line camera 333: Polarized line camera 340: Image generating device 350:Display device 501: 0° polarized image acquisition unit 502: 90° polarized image acquisition unit 503: S0 image generation unit 504: S1 image generation unit 505: S1' image generation unit 506: S1'' image generation unit 507: Detection processing unit 508: Display control unit 601: S1 / S0 calculation unit 701: Difference calculation part 702: Average value calculation unit 703: Image brightness calculation unit 704: Adjustment section 910: Polarizing element

Claims

1. An inspection system for inspecting the appearance of a λ / 4 wavelength member, comprising: a light emitting portion that emits light; a light receiving unit that receives light that is emitted from the light emitting unit, reaches the λ / 4 wavelength member via a polarizing member that forms an angle of 45° or 135° with respect to the polarization angle with respect to the slow axis of the λ / 4 wavelength member, and is transmitted through the λ / 4 wavelength member, and is separated into a direction of 0° and a direction of 90° with respect to the polarization angle of the polarizing member; The received light signal output from the light receiving unit is used to calculate the Stokes parameters s １ Calculate the Stokes parameters s １ an image generating unit that generates an image based on the An inspection system, wherein the wavelength of the light emitted by the light emitting unit is a wavelength at which the phase angle of the light transmitted through the λ / 4 wavelength member is shifted from 90° by an angle range of at least 5° to 15°.

2. The image generation unit The received light signal output from the light receiving unit is used to calculate the Stokes parameters s ０ Calculate The Stokes parameters s １ s constituting the Stokes parameters ０ and generating the image using the value obtained by dividing by The inspection system of claim 1 .

3. The image generation unit The light receiving unit receives light without passing through the λ / 4 wavelength member and the polarization member, and outputs a light receiving signal, which is used to calculate the s １ Correcting the generated image based on The inspection system of claim 1 .

4. The inspection system according to claim 1 , wherein the polarizing member is disposed between the light emitting portion and the λ / 4 wavelength member, and polarizes the light emitted by the light emitting portion.

5. The inspection system of claim 1 , wherein the polarizing member is laminated on the λ / 4 wavelength member.

6. The inspection system according to claim 1 , wherein the λ / 4 wavelength member is a sheet member or a long-sized member.

7. a conveying unit that conveys the λ / 4 wavelength member on which the polarizing member is laminated to an inspection position; The inspection system according to claim 5 , wherein the transport unit transports the λ / 4 wavelength member on which the polarizing member is stacked so that the surface on which the polarizing member is stacked faces the light emitting unit.

8. 8. The inspection system according to claim 7, wherein the slow axis of the λ / 4 wavelength member is shifted by 45° or 135° with respect to the conveying direction when the conveying unit conveys the long-sized member.

9. The inspection system according to claim 7 , wherein the 0° direction in which the light is separated with respect to the polarization angle of the polarizing member is parallel to the conveying direction in which the conveying section conveys the elongated member.

10. The inspection system according to claim 7 , wherein the 90° direction in which the light is separated relative to the polarization angle of the polarizing member is perpendicular to the conveying direction in which the conveying section conveys the elongated member.

11. The inspection system according to claim 3 , wherein a detection process is performed on the image corrected by the image generating unit to detect defects in the appearance of the λ / 4 wavelength member.

12. An inspection method for an inspection system that inspects the appearance of a λ / 4 wavelength member, comprising: a light receiving step of receiving light that is emitted from a light emitting unit that emits light, reaches the λ / 4 wavelength member via a polarizing member that forms an angle of 45° or 135° with respect to the polarization angle with respect to the slow axis of the λ / 4 wavelength member, and is transmitted through the λ / 4 wavelength member, and is separated into a direction of 0° and a direction of 90° with respect to the polarization angle of the polarizing member; The light receiving signal output in the light receiving step is used to configure the Stokes parameters s １ Calculate the Stokes parameters s １ an image generating step of generating an image based on the an inspection method, wherein the wavelength of the light emitted by the light emitting portion is a wavelength at which the phase angle of the light transmitted through the λ / 4 wavelength member is shifted from 90° by an angle range of at least 5° to 15°;

13. An inspection program for an inspection system that inspects the appearance of a λ / 4 wavelength member, a light receiving step of receiving light that is emitted from a light emitting unit that emits light, reaches the λ / 4 wavelength member via a polarizing member that forms an angle of 45° or 135° with respect to the polarization angle with respect to the slow axis of the λ / 4 wavelength member, and is transmitted through the λ / 4 wavelength member, and is separated into a direction of 0° and a direction of 90° with respect to the polarization angle of the polarizing member; The light receiving signal output in the light receiving step is used to configure the Stokes parameters s １ Calculate the Stokes parameters s １ an image generating step of generating an image based on the The wavelength of the light emitted by the light emitting unit is a wavelength at which the phase angle of the light transmitted through the λ / 4 wavelength member is shifted from 90° by an angle range of at least 5° to 15°.

Images