CN109655230B

CN109655230B - Display panel inspection device and display panel inspection method

Info

Publication number: CN109655230B
Application number: CN201811191856.6A
Authority: CN
Inventors: 水野邦广; 池内秀树
Original assignee: Micronics Japan Co Ltd
Current assignee: Micronics Japan Co Ltd
Priority date: 2017-10-12
Filing date: 2018-10-12
Publication date: 2021-01-05
Anticipated expiration: 2038-10-12
Also published as: TWI661191B; JP2019074323A; CN109655230A; KR20190041418A; TW201923336A; KR102123488B1

Abstract

Provided are a display panel inspection device and a display panel inspection method for appropriately performing lighting inspection on a display panel having a curved portion on the outer periphery. The display panel inspection device includes: a mounting table on which a display panel is mounted; a camera; an optical system for adjusting an optical path; an image synthesis condition setting unit that sets an image synthesis condition for synthesizing a direct image and an indirect image, the direct image being an image captured by the camera without via the optical system and the indirect image being an image captured by the imaging unit via the optical system, based on marks appearing in the direct image and the indirect image, respectively, included in the image captured by the camera in a state where a mark parallel to a boundary between the flat portion and the curved portion is displayed on the display panel; and an image combining unit that combines a direct image and an indirect image included in an image captured by the camera in a state where the display panel is fully lit, based on the image combining condition.

Description

Display panel inspection device and display panel inspection method

Technical Field

The present invention relates to a display panel inspection apparatus for inspecting a display panel.

Background

In a display panel such as a liquid crystal display panel or an organic EL (organic electroluminescence) display panel (hereinafter, also simply referred to as a panel or a display panel), or a display device incorporating a display panel (for example, a display, a personal computer, a mobile terminal (a tablet terminal, a smartphone, a mobile phone, or the like)), appearance and a lighting state of the display panel are inspected during a manufacturing process or before shipment. From the past, the following method is performed in the inspection of the appearance and lighting state of the display panel: a display panel as an object to be inspected is photographed by an image pickup means such as a camera, and inspection is performed based on the photographed image.

Patent document 1 discloses a technique relating to an image quality inspection apparatus, the technique including: a horizontally arranged liquid crystal display panel as a test object is photographed by a CCD camera installed above in a state where all pixels (pixels in japanese) of the liquid crystal display panel are in a display operation (hereinafter, also referred to as a lighting state), a planar image of the liquid crystal display panel is acquired, and the planar image is subjected to image processing, thereby specifying a defective pixel with insufficient luminance.

Patent document 2 discloses a technique relating to an appearance inspection apparatus, the technique including: a reflector is disposed on a side of a horizontally disposed liquid crystal display panel as an object to be inspected, and light from a side surface of the object to be inspected is reflected toward a television camera disposed above the reflector to image a plane and a side surface of the object to be inspected.

Patent document 1: japanese patent laid-open No. 2008-67154

Patent document 2: japanese patent laid-open No. 2005-3488

Disclosure of Invention

Problems to be solved by the invention

A display panel having a curved display surface as a subject to be inspected may be inspected. In particular, since the organic EL panel can be made flexible, there has been a display device in which the organic EL panel is assembled in a state where the organic EL panel is partially or entirely bent.

In the inspection of the display state of the display panel in such a curved state (hereinafter also referred to as lighting inspection), when it is intended to capture the entire panel in a state where all pixels are lit with one camera, an image of the curved portion may be unclear or may not be captured. For example, when a display panel which is rectangular in plan view, has only the peripheral edge portions of a pair of opposing sides curved convexly toward the back side, and has a flat space between the two curved portions is used as a subject, and when the entire panel is imaged using a camera disposed at a position opposing the center of the panel in a state where all pixels of the subject are lit as in the inspection apparatus described in patent document 1 to obtain an image, the angle between the normal direction of each pixel of the peripheral curved portion and the camera direction increases toward the edge side of the panel. In general, the luminance of each pixel is the largest in the normal direction and becomes smaller as the angle with respect to the normal direction becomes larger, and therefore, the luminance becomes smaller toward the edge side with respect to the curved portion. Further, when the angle between the normal direction of each pixel and the camera direction is increased, the width of the image of the captured pixel may be narrowed and may be unclear, or a portion on the near side may be blocked and may not be captured. Therefore, a sharp image may not be obtained at the curved portion of the peripheral edge, and the lighting inspection may not be performed appropriately.

Therefore, the following method is considered: as in the appearance inspection apparatus described in patent document 2, a reflector is disposed on a side of a curved portion of a display panel as an object to be inspected, and light from the side of the display panel is reflected toward the camera side, whereby a planar image and a side image are captured by the same camera. However, in this case, the following problems are conceivable: since a difference in optical length occurs between a plane image directly captured by a camera and a side image captured via a reflector, when the difference is not within the range of the depth of field of the camera, it is necessary to perform plane image capturing and side image capturing separately in focus, and it takes time to check them.

In this case, the curved portion is repeatedly captured in both the plane image and the side image. Moreover, there is a possibility that: in the images of these curved portions, portions where sufficient brightness for inspection is not obtained for the reasons described above are included. Namely, there is a possibility that: the luminance deficient portions are generated on both sides in the plane image, and the luminance deficient portions are also generated on one side or both sides in the side image. Therefore, the following problems are also conceivable: the position (address) of each pixel in the captured image cannot be easily determined when the lighting inspection is performed.

Accordingly, an object of the present invention is to provide a display panel inspection apparatus capable of appropriately performing a lighting inspection on a display panel having a curved portion on an outer periphery thereof.

Means for solving the problems

In order to achieve the above object, a first aspect of the present invention provides a display panel inspection apparatus comprising: a mounting table on which a display panel as a subject to be inspected is mounted, the display panel having a flat surface portion and a bent portion bent at least on one side of an outer periphery of the flat surface portion; an imaging unit provided to face the planar portion of the display panel; an optical system that is provided on a side of a space between the display panel and the imaging unit so as not to block an optical path of light that is emitted from the display panel and that directly reaches the imaging unit, the optical system causing a corrected optical path to coincide with an optical path of light that is emitted from the display panel and that directly reaches the imaging unit, the corrected optical path being an optical path obtained by converting an optical path of light that is emitted from the display panel and that is incident on the optical system and that reaches the imaging unit into an optical path in air; an image synthesis condition setting unit that sets an image synthesis condition for synthesizing a direct image and an indirect image, the direct image being an image captured by the imaging unit without passing through the optical system, and the indirect image being an image captured by the imaging unit with passing through the optical system, based on marks appearing in the direct image and the indirect image, respectively, included in the image captured by the imaging unit in a state where the marks parallel to the boundary between the flat portion and the curved portion are displayed in the display panel; and an image combining unit that combines a direct image and an indirect image included in the image captured by the imaging unit in a state where the display panel is fully lit, based on the image combining condition set by the image combining condition setting unit.

The display panel inspection apparatus according to the present invention is characterized by further comprising an inspection unit that specifies an image portion corresponding to each pixel of the display panel in the image synthesized by the image synthesis unit and inspects the presence or absence of a defect of a panel pixel based on a luminance of each image portion.

The display panel inspection apparatus according to the present invention is characterized by further comprising a mark setting means for setting a position at which the mark is displayed on the display panel.

In the display panel inspection apparatus according to the present invention, the marker setting means sets the marker at a position having a predetermined brightness or higher in both the direct image and the indirect image.

In the display panel inspection apparatus according to the present invention, the mark setting means reads the indirect image in units of lines parallel to a boundary between the flat surface portion and the curved portion, sets a region having a predetermined brightness or higher as a settable region, temporarily sets the mark at a position within the settable region, and sets the position using the temporarily set mark when the mark appearing in the direct image is the predetermined brightness or higher when the temporarily set mark is displayed on the display panel.

In the display panel inspection apparatus according to the present invention, the mark setting means sets a position of a predetermined proportion from one side to the other side parallel to the boundary between the flat surface portion and the curved portion in the settable region as a position to be temporarily set in the settable region.

In order to achieve the above object, a first aspect of the present invention is a method for inspecting a display panel as an object to be inspected, based on a direct image and an indirect image, the direct image being an image of the display panel captured by an imaging means provided above and the indirect image being an image of the display panel captured through an optical system provided on a lateral side, the method including: an image synthesis condition setting step of setting a synthesis condition of a direct image and an indirect image based on an image captured by the imaging means in a state where a mark parallel to a boundary between the flat surface portion and the curved portion is displayed on a display panel; an image combining step of combining a direct image and an indirect image according to the image combining conditions set in the image combining condition setting step, based on the image captured by the imaging means in a state where the display panel is fully lit; and an inspection step of specifying an image portion corresponding to each pixel of the display panel in the synthesized image synthesized in the image synthesis step, and inspecting the presence or absence of a defect in a panel pixel based on the brightness of each image portion.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the display panel inspection apparatus and the display panel inspection method of the present invention, it is possible to appropriately perform lighting inspection on a display panel having a curved portion on the outer periphery.

Drawings

Fig. 1 is an explanatory diagram showing a schematic configuration of a display panel inspection apparatus according to a first embodiment of the present invention.

Fig. 2 is a diagram showing a display panel mounted on the display panel inspection apparatus according to the first embodiment of the present invention.

Fig. 3 is a functional configuration diagram illustrating a configuration of an inspection processing device provided in the display panel inspection device according to the first embodiment of the present invention.

Fig. 4 is a flowchart showing the processing contents of the flag setting processing in the display panel inspection apparatus according to embodiment 1 of the present invention.

Fig. 5 is an explanatory diagram for explaining the marker setting process using a captured image captured by a camera provided in the display panel inspection apparatus according to the first embodiment of the present invention.

Fig. 6 is a flowchart showing the processing contents of the image synthesis condition setting process in the display panel inspection apparatus according to embodiment 1 of the present invention.

Fig. 7 is a flowchart showing the processing contents of the image composition processing and the inspection processing in the display panel inspection apparatus as embodiment 1 of the present invention.

Fig. 8 is an explanatory diagram for explaining the processing contents of the image combination condition setting processing, the image combination processing, and the inspection processing in the display panel inspection apparatus according to the first embodiment of the present invention.

Description of the reference numerals

1: a display panel inspection device; 11: a mounting table; 12: a camera (image pickup unit); 13: an optical system; 13 a: a mirror; 13 b: a prism; 15: a panel driving signal generator; 16: a power supply for the panel; 17: an inspection processing device; 19: an input section; 20: an output section; 171 a: a flag setting unit; 171 b: an image synthesis condition setting unit; 171 c: an image synthesizing unit; 171 d: an inspection unit; 172: a storage unit; 173: and an external network unit.

Detailed Description

Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same or equivalent parts and components are denoted by the same or equivalent reference numerals. It should be noted, however, that the drawings are diagrammatic and not actual in nature. It is needless to say that the drawings include portions having different dimensional relationships and ratios from each other.

The embodiments described below are illustrative of devices and the like for embodying the technical ideas of the present invention, and the technical ideas of the present invention are not limited to the following materials, shapes, structures, arrangements, and the like of the respective components. The technical idea of the present invention can be variously modified in the claims.

Embodiments of a display panel inspection apparatus according to the present invention will be described in detail below with reference to the drawings.

< first embodiment >

Fig. 1 is an explanatory diagram showing a schematic configuration of a display panel inspection apparatus according to a first embodiment of the present invention. 3 fig. 32 3 is 3a 3 view 3 showing 3a 3 display 3 panel 3( 3 display 3 panel 3) 3 mounted 3 on 3 the 3 display 3 panel 3 inspection 3 apparatus 3 according 3 to 3 the 3 first 3 embodiment 3 of 3 the 3 present 3 invention 3, 3 in 3 which 3 fig. 32 3( 3a 3) 3 is 3a 3 partial 3 plan 3 view 3 and 3 fig. 32 3( 3b 3) 3 is 3a 3 sectional 3 view 3 taken 3 along 3 line 3a 3- 3a 3. 3

(integral structure of display panel inspection apparatus)

As shown in fig. 1, the display panel inspection apparatus 1 according to the first embodiment includes a mounting table 11 on which a display panel P as an object to be inspected is mounted and fixed. As shown in fig. 1 and 2, the display panel P mounted on the mounting table 11 has a flat surface portion P1 and bent portions P2 and P3 bent at two opposite sides of the outer periphery of the flat surface portion P1. In the case where the display panel P is assumed to extend flat, panel pixels are arranged in a matrix shape in the X1-X2 direction and the Y1-Y2 direction with one vertex of one bent portion P2 of the display panel P as an origin.

As shown in fig. 1, the camera 12 as an imaging means is disposed above the center of the plane portion P1 of the display panel P (in the Z1 direction) so as to face the plane portion P1 of the display panel P. The camera 12 can obtain a captured image in the display state as a digital image by capturing an image of the display panel P on which the image is displayed, and for example, a CCD camera can be used. The camera 12 is fixed by a camera fixing mechanism not shown.

An optical system 13 including a mirror 13a and a prism 13b is provided so that the camera 12 can simultaneously photograph the curved portions P2, P3 and the flat surface portion P1 of the display panel P. The reflecting mirror 13a and the prism 13b are disposed on the side of the space between the display panel P and the camera 12 so as not to block the optical path of the light emitted from the display panel P and directly reaching the camera 12.

The luminance of light emitted from each pixel of the display panel P is the maximum in the normal direction of each pixel, and becomes smaller as it is inclined from the normal direction. Therefore, regarding the light emitted from each panel pixel of the plane portion P1, the luminance in the vertical direction upward (Z1 direction) is large, and the luminance decreases as it inclines from the Z1 direction. In addition, regarding the light emitted from each panel pixel of the bent portions P2 and P3, the luminance in the normal direction of the tangent plane of the panel pixel is large, and the luminance decreases as the light is inclined from the normal direction. Further, since the bending portions P2 and P3 are bent in the Z2 direction with the Y1-Y2 direction as the axial direction, the normal direction of the tangent plane of each panel pixel of the bending portion P2 is inclined from the Z1 direction to the X2 direction as the pixel on the edge side is directed toward the normal direction of the tangent plane, and the normal direction of the tangent plane of each panel pixel of the bending portion P3 is inclined from the Z1 direction to the X1 direction as the pixel on the edge side is directed toward the normal direction of the tangent plane.

Therefore, although there is a tendency that the brightness of light from the center is high and the brightness is decreased toward the periphery with respect to light that reaches the camera 12 directly from the plane portion P1 without passing through the optical system 13, the entire plane portion P1 can be clearly imaged by appropriately positioning the camera in consideration of the angle of view of the display panel P, the performance of the camera 12, and the like. However, since the inclination of the light directly reaching the camera 12 from the bending portions P2 and P3 without passing through the optical system 13 increases toward the edge side from the normal direction of the tangential plane, the brightness decreases sharply toward the edge side, and clear imaging cannot be performed.

On the other hand, some of the light emitted from the plane portion P1 and the bent portions P2 and P3 of the display panel P reaches the camera 12 via the optical system 13. That is, a part of the light emitted from the curved portions P2 and P3 and the flat portion P1 of the display panel P and reflected by the mirror 13a is guided to the prism 13b, passes through the prism 13b, and reaches the camera 12. The prism 13b is disposed on an optical path along which light mainly coming from the side of the display panel P is reflected by the mirror 13a and reaches the camera, and is constituted by a light transmitting member such as glass, for example.

Light travels faster in glass than in air. That is, the optical path length in glass is reduced when converted to the optical path length in air.

Therefore, the mirror 13a and the prism 13b determine the optical path of the light as follows: the corrected optical path length obtained by converting the optical path length emitted from the display panel P, reflected by the mirror 13a, incident on the prism 13b, and reaching the camera 12 into an optical path length in the air is made to coincide with the optical path length emitted from the center of the display panel P and reaching the camera 12 directly. This allows the camera 12 to capture an image while aligning the focal plane of the plane portion P1 with the focal planes of the curved portions P2 and P3, thereby obtaining one captured image in which the plane portion P1 and the curved portions P2 and P3 are captured.

Therefore, the light reaching the camera 12 via the optical system 13 tends to have a high luminance in the portion irradiated in the normal direction of the tangent plane of the panel pixels of the bending portions P2 and P3 and a lower luminance toward the periphery thereof, but by appropriately setting the position and angle of the mirror 13a, the bending portion P2 can be very clearly imaged including the panel pixels at the extreme end portions of the bending portions P2 and P3 (the panel pixels arranged in the Y1-Y2 direction at both ends in the X1-X2 direction). However, since the inclination of the light reaching the camera 12 from the plane portion P1 side of the bent portions P2 and P3 and the plane portion P1 via the optical system 13 is large from the normal direction of each panel pixel and is larger toward the center side (the X1 direction in the bent portion P2 and the X2 direction in the bent portion P3), the brightness is abruptly reduced toward the center side, and thus clear imaging cannot be performed.

As described above, the curved portions P2 and P3 at both ends of the planar image (hereinafter also referred to as a direct image) directly captured by the camera 12 without passing through the optical system 13 are not sharp, and the side image (hereinafter also referred to as an indirect image) indirectly captured by the camera 12 through the optical system 13 is not sharp at the planar portion P1. Then, the unclear portions of the direct image and the indirect image are captured clearly in the other image.

The display panel inspection apparatus 1 includes a panel drive signal generator 15, a panel power supply 16, an inspection processing device 17, an input unit 19, and an output unit 20.

The panel drive signal generator 15 causes the display panel P to display an inspection screen or the like based on an instruction of the inspection processing device 17.

The panel power supply 16 supplies power to the display panel P.

The input unit 19 inputs information such as operation and data of the display panel inspection apparatus 1, for example, a mouse and a keyboard, and supplies the information to the inspection processing apparatus 17.

The output unit 20 displays a screen or the like based on an instruction from the inspection processing device 17, and includes an operation monitor 20a and an image monitor 20 b. The operation monitor 20a displays a screen for performing operations of the display panel inspection apparatus 1 and its components (the camera 12, the panel drive signal generator 15, and the panel power supply 16), various settings, data input, operation status display, and the like. The image monitor 20b displays an image captured by the camera 12, an image obtained by image processing the image by the inspection processing device 17, and the like.

The inspection processing device 17 may be constituted by a general-purpose computer such as a PC (personal computer), and controls an external device such as the camera 12, the panel drive signal generator 15, and the panel power supply 16, performs processing for generating a screen to be displayed on the display panel at the time of inspection, performs image processing on an image captured by the camera 12, or performs processing for specifying a defective pixel based on the image subjected to the image processing.

Fig. 3 is a functional configuration diagram illustrating the configuration of the inspection processing device 17 provided in the display panel inspection device 1.

As shown in fig. 3, the inspection processing device 17 includes a processing unit 171 as a functional block, and the processing unit 171 is realized by a program and a CPU that executes various processes based on the program. The processing unit 171 is connected to a storage unit 172 that stores various data. The data stored in the storage unit 172 includes a storage area functioning as a work area, various programs for implementing the processing unit 171, captured image data captured by the camera 12, image data subjected to image processing by the processing unit 171, screen data for displaying a display panel at the time of inspection determined by the processing unit 171, various data calculated for specifying defective pixels, data for controlling various external devices, and the like. The storage unit 172 is implemented by a storage medium such as a memory or a hard disk. An external network unit 173 for connecting various external devices is connected to the processing unit 171. External devices such as the input unit 19, the output unit 20, the camera 12, the panel drive signal generator 15, and the panel power supply 16 are connected via the external network unit 173, and data is transmitted and received.

The processing unit 171 of the inspection processing device 17 virtually constructs the marker setting unit 171a, the image synthesis condition setting unit 171b, the image synthesis unit 171c, the inspection unit 171d, and the external device control unit 171e by the execution program and various data stored in the storage unit 172 and the arithmetic processing such as the CPU executed by these.

As described above, the direct image and the indirect image have repeatedly captured portions. That is, a part of the curved portion P2 and the flat portion P1 are captured in the direct image, and a part of the flat portion P1 and the curved portion P2 are captured in the indirect image.

However, as described above, the portions on the side of the curved portions P2, P3 captured in the direct image, the flat portions P1 captured in the indirect image, and the flat portion P1 include regions (unclear regions) whose light amounts are insufficient for performing the lighting inspection. Therefore, although it is necessary to perform synthesis using a clearly captured image, since both ends of the direct image in the X1-X2 direction are not clear, the address of each pixel (the coordinate of the pixel with respect to the origin) cannot be determined in the direct image, and it is difficult to accurately synthesize an indirect image. Therefore, the display panel displays the marks displayed in both the direct image and the indirect image, and generates the clipped region in the captured image and the conditions for image composition based on the information when the image is composed with the marks as reference. Then, by synthesizing the images according to the conditions, a synthesized image composed of an entirely clear image can be obtained. As the mark, a linear display parallel to the boundary between the plane portion P1 and the bent portions P2 and P3 can be used, and the display is preferably performed by a row of panel pixels. The mark is preferably a continuous line, but may be an intermittent line.

Therefore, the marker setting unit 171a sets conditions such as the position of the marker displayed on the display panel as a reference for setting image combining conditions for combining the direct image and the indirect image captured by the camera 12. The conditions such as the position of the set flag are stored in the storage unit 172.

The image combination condition setting unit 171b sets an image area for combining the captured direct image and indirect image or sets a combination method of the direct image and indirect image with reference to a mark displayed on the display panel. The set image area and the set combination mode are stored in the storage unit 172 as image combination conditions.

The image combining unit 171c combines the direct image and the indirect image according to the image combining condition set by the image combining condition setting unit 171 b. In this case, correction of the image such as correction of shape distortion of the indirect image and brightness matching between the direct image and the indirect image is performed. The created composite image is stored in the storage unit 172.

The inspection unit 171d determines the image elements (pixels) of the portion corresponding to each panel pixel based on the image synthesized by the image synthesis unit 171c, and finds the luminance of each pixel based thereon. Further, the inspection unit 171d determines the presence or absence of a defective pixel and specifies the address of the defective pixel based on the obtained brightness of each pixel. The determination result of the presence or absence of a defective pixel and the address of the specified defective pixel are stored in the storage unit 172.

The external device control unit 171e performs processing of information input from the input unit 19 and processing of an output screen output to the output unit 20. Further, control signals for controlling the panel power supply 16, the panel driving signal generator 15, and the camera 12 are transmitted, and signals and image data transmitted from these devices are processed, and the image data is stored in the storage unit 172.

Next, the operation of the display panel inspection apparatus 1, which is embodiment 1 of the present invention, will be described. The display panel inspection apparatus 1 according to the first embodiment of the present invention mainly performs a flag setting process, an image synthesis condition setting process, an image synthesis process, and an inspection process. Therefore, each process will be described in detail below.

Mark setting processing

Fig. 4 is a flowchart showing the processing contents of the flag setting process in the display panel inspection apparatus 1 according to embodiment 1 of the present invention. Fig. 5 is an explanatory diagram for explaining the marker setting process using the captured image captured by the camera 12. Here, an example is shown as follows: when the panel drive signal generator 15 lights the linear mark of any one of the colors R (red), G (green), and B (blue) (any one of the pixels of the three primary colors) on the display panel P having no defective pixel whose lighting inspection is completed based on the instruction of the inspection processing device 17, the camera 12 captures a part of the captured image. As shown in fig. 5, the captured image includes both a direct image emitted from the display panel P and captured by the camera 12 without passing through the optical system 13 and an indirect image emitted from the display panel P and captured by the camera 12 with passing through the optical system 13. In the explanatory diagram shown in fig. 5, only the upper left portion of the captured image is shown, and the left portion of the indirect image is captured on the upper side and the upper left portion of the front image is captured on the lower side. Further, the following are illustrative diagrams: the indirect image is an indirect image using the captured image acquired in step S105 of the flag setting process described later, and the direct image is a direct image using the captured image acquired in step S115.

First, the display panel P having no defective pixel is fixed on the mounting table 11. Next, as shown in fig. 4, when the mark setting process is executed based on the user operation of the input section 19, the mark setting unit 171a first sets the spot No. 1 as the line address (step S101). Here, regarding the line address, when a pixel located at one vertex of the curved portion P2 of the display panel P is taken as the origin (1, 1), the line address is an address of a panel pixel of the display panel P in the scanning direction (X1 direction). The line addresses (1, 1) to (1, n) (n is the number of pixels in the Y1 direction) are the line addresses of point No. 1.

Next, the mark setting unit 171a controls the panel driving signal generator 15 to display the lines of the set line addresses (hereinafter also referred to as line marks) after turning on the panel power supply 16 to supply power to the display panel P (step S103). In this embodiment, the line mark displays any one of R (red), G (green), and B (blue) (any one of the pixels of three primary colors), and the portion (background) of the display panel P other than the line mark is black (the pixel is in a non-lighting state).

Then, the mark setting unit 171a takes an image of the display panel P with the camera 12 to acquire the taken image G1 (step S105). At this time, in the captured image G1, one indirect image G12 is captured on the upper side, another indirect image G13 is captured on the lower side, and a direct image G11 is captured in the center.

Next, the mark setting unit 171a determines whether or not the line mark in the indirect image G12 in the captured image G1 can be recognized to the extent that each pixel can be distinguished. In this determination, it is determined whether or not the image portion of the line mark is equal to or higher than a predetermined brightness (step S107).

When the luminance of the image portion of the line marker in the indirect image G12 is equal to or higher than the predetermined luminance (yes in step S107), the line marker is determined to be recognizable in the indirect image G12, the marker setting unit 171a increments the line address by 1 in the X1 direction (step S109), and the process proceeds to step S103.

On the other hand, when the brightness of the image portion of the line marker in the indirect image G12 is less than the predetermined brightness (no in step S107), it is determined that the line marker cannot be recognized in the indirect image G12, and the process proceeds to step S111.

Next, the flag setting unit 171a temporarily sets, as an appropriate position, the line address increased by a number of a predetermined ratio to the total number of the numbers increased in step S109 as a row flag (step S111). The predetermined ratio is set to 1/2 (carry if not completely divided), but an appropriate ratio may be set in advance in consideration of the shape of the bending portion. Specifically, in the case where the total of the increased numbers is 52, as shown in fig. 5, the line flag of the line address of point No. 1 is L1 (line addresses (1, 1) to (1, n)), and the line flag of the line address determined in step S107 to be equal to or less than the predetermined brightness (line address of point No. 53) is L3 (line addresses (53, 1) to (53, n)). Since the number of increments from L1 to L3 is 52, the flag setting unit 171a temporarily sets the line flag L2((27, 1) to 27, n)) incremented by 1/2 of 52, that is, by the line address of 26 (the line address of spot No. 27), as an appropriate position of the flag. The region surrounded by L1 and L3 is referred to as a settable region.

In this manner, by repeating the processing of steps S103 to S109 until step S111 is reached, that is, by repeating the panel display and the image pickup of the line address until the line address is less than the predetermined brightness while increasing the line address, the position of the line mark that cannot be recognized in the indirect image G12 is specified, and the line address of the line mark that can be recognized sufficiently in the middle can be temporarily set based on the position of the line mark.

Next, the flag setting unit 171a controls the panel driving signal generator 15 to turn on the line flag of the line address L2 temporarily set to the appropriate position (step S112). At this time, the colors of the line mark and the background are the same as those at the time of step S103.

Next, the display panel P is photographed by the camera 12 to acquire a photographed image G2 (step S115). The imaging conditions (the position and setting of the camera 12, the position of the display panel P, the illumination, and the like) of the captured image G2 are the same as those when the captured image G1 is captured. In the captured image G2, one indirect image G22 is captured on the upper side, another indirect image G23 is captured on the lower side, and a direct image G21 is captured in the center.

Next, the flag setting unit 171a determines whether or not the line flag L2 can be recognized to the extent that each pixel can be discriminated in the direct image G21. In this case, it is determined whether or not the image portion of the line marker L2 in the direct image G21 is equal to or higher than a predetermined brightness (step S117).

When it is determined that the brightness of the line marker displayed in the direct image G21 is equal to or greater than the predetermined value (yes in step S117), it is estimated that the line marker at the line address temporarily set in both the indirect image and the direct image can be sufficiently recognized for the lighting inspection to be performed. Therefore, the mark setting unit 171a formally sets the temporarily set line address as an appropriate line address as a line mark, and stores the line mark in the storage unit 172 (step S119).

On the other hand, when it is determined that the brightness of the line marker displayed in the direct image G21 is less than the predetermined value (step S117: no), it can be estimated that the line marker of the line address temporarily set cannot detect the brightness sufficient for executing the lighting check in the direct image or that an error has occurred due to another reason. Therefore, the flag setting unit 171a causes the output unit 20 to display an error display (step S121).

Further, when it is determined in step S117 that the luminance of the line marker displayed in the direct image G21 is less than the predetermined threshold value (no), the output unit 20 is caused to display an error display (step S121), but the present invention is not limited to this, and for example, a position (for example, a position shifted by 1 pixel or several pixels) shifted to the plane portion P1 side (X1 direction) from the temporarily set line address in the range of "L1" to "L3" may be set as the temporarily set line address and the process may return to step S112. Thus, there is a possibility that: the line addresses of the line markers that can be recognized in both the indirect image and the direct image can be determined while repeatedly executing steps S112 to S121. If the luminance of the direct image G21 is not equal to or higher than the predetermined threshold even after the predetermined number of times of processing, there is a possibility of other causes, and therefore, it is preferable to perform the error display.

In addition, both the direct image and the indirect image are captured in the captured image capturing process in step S105 and step S115, but only the indirect image on which the line marker is displayed may be captured in step S105 and only the direct image may be captured in step S115, thereby shortening the processing time.

In the above description, only one indirect image G22 has been described as to the setting of the line flag of the indirect image, but the line address of the line flag may be set in the same process as in the other indirect image G23, or may be set at a symmetrical position based on the line address of the line flag of the one indirect image G22.

By performing the above-described mark setting processing, it is possible to appropriately set the line address of the line mark that can be favorably recognized in both the direct image and the indirect image.

Image Synthesis Condition setting processing

Fig. 6 is a flowchart showing the processing contents of the image synthesis condition setting process in the display panel inspection apparatus 1 according to embodiment 1 of the present invention. Fig. 8 (a) is an explanatory diagram for explaining the image synthesis condition setting process. In the diagram of the captured image G3 in fig. 8 (a), small white circles indicate the image of the panel pixels in the non-lit state, and small black circles indicate the image of the panel pixels in the lit state as a marker. First, the display panel P to be inspected is fixed to the mounting table 11. Here, the display panel P mounted on the mounting table 11 is a display panel of the same specification as the display panel fixed to the mounting table 11 in the mark setting process, and is an unchecked display panel. As shown in fig. 6, the image combination condition setting unit 171b controls the panel drive signal generator 15 to light the line mark of the line address set in the mark setting process after turning on the panel power supply 16 to supply power to the display panel P (step S201). At this time, the color of the mark is displayed as any one of the three primary colors, and the background color is set to "black" (unlit).

Next, the image combination condition setting unit 171b captures an image with the camera 12 in a state where the line marker is turned on, and acquires the captured image G3 (step S203). In this case, the imaging conditions are the same as those in the flag setting processing. As shown in fig. 8 (a), the captured image G3 includes both a direct image G31 captured by the camera 12 without passing through the optical system 13 and indirect images G32 and G33 captured by the camera 12 with passing through the optical system 13. In the captured image G3, similarly to the captured images G1 and G2 captured by the marker setting process, one indirect image G32 is captured on the upper side, the other indirect image G33 is captured on the lower side, and the direct image G31 is captured in the center. In addition, in the captured image G3, line markers appear in both the direct image G31 and the indirect images G32 and G33. Further, image correction is performed on the indirect image G32 of the captured image G3 to correct the shape distortion to a rectangular shape with reference to the center portion of the direct image G31.

Next, the image combination condition setting unit 171b recognizes the line marker from the captured image G3 for each of the direct image G31 and the indirect image G32, determines the position of the line marker on the captured image G3, and stores the line marker in the storage section 172. As the determination of the position, for example, an address in units of image elements with respect to a reference point in the captured image G3 (here, the upper left vertex of the captured image G3) can be determined (step S205).

Next, the image combination condition setting unit 171b binarizes the captured image G3 captured in step S203 to extract edges, recognizes the contour lines of the direct image G31 and the indirect image G32, determines the positions of the contour lines on the captured image G3, and stores the contour lines in the storage unit 172. As the determination of the position, an address in units of image elements with respect to the reference point in the captured image G3 can be determined. As the contour lines to be determined, there are two contour lines at both ends in the Y1-Y2 direction sandwiched by two line markers in the direct image G31, a contour line at the outer end of the bending portion P2 in the X1-X2 direction in the indirect image G32, and two contour lines at both ends in the Y1-Y2 direction sandwiched by the contour lines and the line markers. Further, as also shown in fig. 8 a, the range of the region surrounded by the line marks and the contour lines (direct-image cutout region) in the direct image G31 on the captured image G3 and the range of the region surrounded by the line marks and the contour lines (indirect-image cutout region) in the indirect image G32 on the captured image G3 are determined and stored in the storage section 172 (step S207). The range of the specified cut-out region can be expressed as an address in units of image elements with respect to the reference point in the captured image G3. Further, the image portions of the line marks are also included in the direct image cutout region and the indirect image cutout region. In the explanatory diagram shown in fig. 8 a, the indirect images G32 and G33 have indirect image cutout regions at the two outer sides (panel end sides) of the broken lines, and the direct image G31 has direct image cutout regions at the positions inside the two upper and lower broken lines.

Next, the combining conditions of the direct image and the indirect image are set based on the positions of the line markers of the direct image G31 and the indirect image G32 on the captured image G3 determined by the processing of step S205 and the ranges of the direct-image cutout region and the indirect-image cutout region on the captured image G3 determined by the processing of step S206 (step S209). In this embodiment, since an image clipped in the indirect image clipping region is superimposed on the direct image G31 in the captured image G3 to be combined, a method of setting image combining conditions in this case will be described. In the following description, an image cut in the indirect image cutting region is also referred to as a "cut indirect image", and an image cut in the direct image cutting region is referred to as a "cut direct image".

The image combination condition setting unit 171b stores the range of the indirect image cutout region determined in step S207 in the captured image G3 in the storage unit 172 as one of the image combination conditions (hereinafter also referred to as an image cutout condition). Further, the position of the cut indirect image in the captured image G3 when the cut indirect image is moved to a position where the position of the line marker in the image coincides with the position of the line marker of the direct image G31 in the captured image G3 is specified and stored in the storage unit 172 as one of the image combining conditions (hereinafter also referred to as an image moving condition). This processing is performed for the two indirect images G32, G33, respectively. Here, the position of the movement destination of the clipped indirect image determined as the image combining condition may be an address in units of image elements with the reference point (for example, upper left vertex) of the captured image G3 as the origin, or an address in units of image elements with the reference point (for example, upper left vertex) of the clipped indirect image area as the origin. The region deleted from the captured image G3 is also stored in the storage unit 172 as one of the image combining conditions (hereinafter also referred to as an image deletion condition). As a method of specifying the deletion area, it is possible to specify by using a range indicated by an address in units of image elements with a reference point (for example, upper left vertex) of each image (the captured image G3, the clipped direct image, or the clipped indirect image) as an origin. The portion where the images are superimposed can also be specified by indicating an image that is valid (an image on the top). Here, in the direct image G31, the line mark portion and the portion on the outer side thereof are the range to be deleted, but since all of them are the portions overlapping the cut indirect image, the image synthesis condition is set by designating the cut indirect image side as valid. In the indirect images G32 and G33, the portions other than the indirect image cutout region (portions inside the line markers) are the range to be deleted.

Further, the method of setting the image combination conditions is not limited to this, and for example, the image positions of the cut direct image and the cut indirect image in the captured image G3 when the cut direct image and the cut indirect image are moved to positions at which the line marker portions displayed respectively coincide may be stored as the image combination conditions in the storage unit 172. In this case, the deletion area as the image combining condition is preferably a deletion area in which the effective image in the overlapping state is designated as the cut-out indirect image, and an area other than the cut-out area of the direct image in the direct image G31 and an area other than the cut-out area of the indirect images G32 and G33 are designated as the deletion area.

Image Synthesis and examination Process

Fig. 7 is a flowchart showing the processing contents of image synthesis and inspection in the display panel inspection apparatus 1 as embodiment 1 of the present invention. Fig. 8 (b) to (f) are explanatory views for explaining the principle contents of image synthesis and inspection. In the diagrams showing the captured image K1 and the combined images K2 and K3 in fig. 8 (b) to (d), small white circles indicate images of pixels in a lit state, but the actual number of pixels is not described faithfully, and the schematic diagram is described so that the number of pixels is greatly reduced. Here, the display panel P mounted on the mounting table 11 is held in a state when it is fixed to the mounting table 11 in the above-described image combination condition setting process, and a lighting inspection is performed in this inspection process.

As shown in fig. 7, the image synthesizing unit 171c causes the entire display panel P (the curved portion P2 and the flat portion P1) to be lit up in any one of R (red), G (green), and B (blue) (any one of the pixels of the three primary colors) by the panel drive signal generator 15 (step S301).

Next, the image combining unit 171c captures the entire display panel P fully lit by the camera 12 to take in the captured image K1 (step S303). Here, the imaging conditions are the same as those in the image synthesis condition setting processing. As shown in fig. 8 (b), the captured image K1 includes both a direct image K11 captured by the camera 12 without passing through the optical system 13 and indirect images K12 and K13 captured by the camera 12 with passing through the optical system 13. In the captured image K1, similarly to the captured image G3 captured by the image combination condition setting process, one indirect image K12 is captured on the upper side, another indirect image K13 is captured on the lower side, and the direct image K11 is captured in the center. Since the display panel P is held in the fixed state on the mounting table 11 in the image synthesis condition setting process and the imaging conditions are the same as those in the image synthesis condition setting process, the size of the captured image K1 and the positions of the direct image K11 and the indirect images K12 and K13 in the captured image K1 are the same as those in the captured image G3. The direct image K11 includes a part of the image of the plane portion P1 and the image of the bend portion P2, and the indirect images K12 and K13 also include a part of the image of the plane portion P1 and the image of the bend portion P2.

Next, the image synthesizing unit 171c performs image correction on the captured image K1 taken in before synthesizing the direct image K11 with the indirect image K12 (step S305). Specifically, distortion correction for distorting the shape of the indirect image having passed through the prism into a rectangular shape, and horizontal correction for matching brightness and hue so that no boundary is generated when the direct image and the indirect image are combined are performed. These distortion correction and horizontal correction are performed with reference to the center of the direct image.

Next, the image synthesizing unit 171c generates a synthesized image K2 in which the direct image K11 is connected to the indirect images K12 and K13 in accordance with the image synthesis conditions stored in the storage unit 172, and generates a synthesized image K3 in which only the image of the display panel P is cut out from the synthesized image K2 (step S307). Specifically, in the image combining process according to the image combining conditions, first, the images of the indirect image cutout regions are cut out from the indirect images K12 and K13 of the captured image K1 according to the image cutout conditions, and the cut-out indirect images K121 and K131 are obtained. In the explanatory diagram shown in fig. 8 b, the portions of the indirect images K12 and K13 on both outer sides (panel end sides) of the broken line are cut indirect images K121 and K131. Subsequently, the cut indirect images K121 and K131 are moved according to the image movement conditions. Then, unnecessary image portions are deleted in accordance with the image deletion conditions, resulting in a composite image K2 shown in fig. 8 (c). Then, only the image portion of the display panel P is cut out of the composite image K2, resulting in a composite image K3 shown in fig. 8 (d).

Next, the inspection unit 171d binarizes the generated composite image (step S309). Specifically, the checking unit 171d binarizes based on whether or not the luminance of each image element of the composite image exceeds a predetermined threshold value (step S309), and generates peak information (step S311). The processing of the binarization and the peak information generation will be described.

The pixels of the display panel P and the picture elements of the synthesized image are not limited to one-to-one correspondence, and the picture elements of the synthesized image are generally finer. Since each image element of the composite image K3 shown in fig. 8 (c) includes luminance information, the inspection unit 171d generates a composite image K4 obtained by binarizing based on whether or not the luminance of each image element of the composite image exceeds a predetermined threshold value as shown in fig. 8 (e). The threshold value is preferably set to a value that allows distinguishing between a portion having a panel pixel that emits light and a portion having no panel pixel. By this binarization processing, a portion in which a plurality of image elements equal to or larger than a threshold value are aggregated is scattered in the composite image K4. Hereinafter, the image elements above the threshold value are also referred to as on image elements, the image elements below the threshold value are referred to as off image elements, and the portion where the on image elements are grouped is referred to as an on image element group. When there is no on picture element group in a place where a pixel should be present due to a defect of the pixel, a plurality of off picture elements are selected according to the arrangement state and size of the surrounding on picture element groups, and the selected off picture elements are set as an off picture element group corresponding to the pixel in the place. Hereinafter, the on picture element group and the off picture element group are also collectively referred to as a pixel position picture element group. After all the pixel position image element groups are specified, it is confirmed whether or not the arrangement (the number of rows and the number of columns) thereof matches the arrangement (the number of rows and the number of columns) of the pixels, which is known information, that is, the specification of the display panel P. When the arrangement is uniform, processing for determining the brightness of the image element group at each pixel position is performed. Since the luminance value of each image element is known from the composite image K3 before the binarization processing, the maximum luminance value among the plurality of image elements constituting each pixel position image element group is set as the peak luminance value of the pixel position image element group. Thereby, peak information in which a peak luminance value is set for each pixel position image element group is generated.

Next, the inspection unit 171d determines the presence or absence of a defective pixel and extracts the address of the defective pixel based on the peak information (step S313). First, it is determined whether or not there is a pixel position image element group whose peak luminance value is smaller than a predetermined threshold value based on the peak information generated in step S311. As the threshold, a peak luminance value at which a good or a bad of the panel pixel can be determined is set in advance. The inspection unit 171d determines that there is no defective pixel in the display panel P if the peak luminance value in all pixel position image element groups is equal to or greater than the threshold value. When there is a pixel position image element group whose peak luminance value is smaller than a predetermined threshold value, it is determined that there is a defective pixel in the display panel P, and the number of the defective pixels is also determined. When it is determined that a defective pixel exists, processing for specifying an address of the defective pixel is performed. The process of address determination of the defective pixel will be described with reference to (f) of fig. 8.

Fig. 8 (f) is an explanatory diagram of processing for address specification of a defective pixel in the case where it is determined that there is a defective pixel in the combined image K4 that has been subjected to the binarization processing and corresponds to the peak information. The number of rows (y) to the first row and the number of columns (x) to the first column in the arrangement of pixel position image element groups are counted with the pixel position image element group determined as a defective pixel, whose peak luminance value is smaller than the threshold value, as a starting point, to determine a defective pixel address (x, y). In the case where there are a plurality of pixel-position picture elements which are determined as defective pixels, the processing is performed on them, respectively. The address of the defective pixel thus identified is stored in the storage section 172.

In the above example, the pixel address corresponding to the pixel position image element group having the peak luminance value smaller than the threshold value is determined after the pixel position image element group is specified, but the pixel address corresponding to each pixel position image element group may be determined in advance at the time of peak information generation so that the pixel address is known when the pixel position image element group having the peak luminance value smaller than the threshold value is specified.

As described above, the display panel inspection apparatus 1 according to embodiment 1 of the present invention includes: a mounting table 11 on which a display panel P as an object to be inspected is mounted, the display panel P having a flat surface portion P1 and a bent portion P2 bent at least on one side of an outer periphery of the flat surface portion P1; a camera 12 provided to face a plane portion P1 of the display panel P; an optical system 13 provided on the side of the space between the display panel P and the camera 12 so as not to block the optical path of the light emitted from the plane portion P1 and directly reaching the camera 12, the optical system having a corrected optical path in which the optical path of the light emitted from the display panel P and incident on the optical system and reaching the camera 12 is converted into the optical path in the air, the optical path of the light emitted from the display panel P and incident on the optical system and reaching the camera 12 being matched with the optical path of the light; an image synthesis condition setting unit 171b that sets an image synthesis condition for synthesizing a direct image, which is an image captured by the camera 12 without passing through the optical system 13, and an indirect image, which is an image captured by the imaging unit through the optical system 13, based on marks appearing in the direct image and the indirect image, respectively, included in the image captured by the camera 12 in a state where the mark parallel to the boundary between the plane portion P1 and the curved portion P2 is displayed in the display panel P; and an image combining unit 171c that combines the direct image and the indirect image included in the image captured by the camera 12 in the state where the display panel P is fully lit, based on the image combining condition set by the image combining condition setting unit 171 b.

Therefore, it is possible to synthesize a region having sufficient brightness for performing the lighting inspection, from among the direct image and the indirect image, and perform the lighting inspection based on the synthesized image. This makes it possible to appropriately perform lighting inspection on the display panel P having the curved portion P2 on the outer periphery.

In the above-described embodiments, the case of the display panel having the bent portions on two opposite sides is described, but the present invention is not limited to this, and the present invention can be applied to a display panel having a bent portion on one side or three sides or more, for example.

Further, since it is not necessary to perform the above-described mark setting process each time when inspecting display panels of the same specification, when inspecting a plurality of display panels of the same specification, the image synthesis condition setting process, the image synthesis process, and the inspection process can be performed each time the display panel to be inspected is fixed to the mounting table 11.

Claims

1. A display panel inspection device is characterized by comprising:

a mounting table on which a display panel as a subject to be inspected is mounted, the display panel having a flat surface portion and a bent portion bent at least on one side of an outer periphery of the flat surface portion;

an imaging unit provided to face the planar portion of the display panel;

an optical system that is provided on a side of a space between the display panel and the imaging unit so as not to block an optical path of light that is emitted from the display panel and that directly reaches the imaging unit, the optical system causing a corrected optical path to coincide with an optical path of light that is emitted from the display panel and that directly reaches the imaging unit, the corrected optical path being an optical path obtained by converting an optical path of light that is emitted from the display panel and that is incident on the optical system and that reaches the imaging unit into an optical path in air;

an image synthesis condition setting unit that sets an image synthesis condition for synthesizing a direct image and an indirect image, the direct image being an image captured by the imaging unit without passing through the optical system, and the indirect image being an image captured by the imaging unit with passing through the optical system, based on marks appearing in the direct image and the indirect image, respectively, included in the image captured by the imaging unit in a state where the marks parallel to the boundary between the flat portion and the curved portion are displayed in the display panel; and

and an image combining unit that combines a direct image and an indirect image included in the image captured by the imaging unit in a state where the display panel is fully lit, based on the image combining condition set by the image combining condition setting unit.

2. The display panel inspection apparatus according to claim 1,

the image synthesizing device further includes an inspection unit that specifies an image portion corresponding to each pixel of the display panel in the image synthesized by the image synthesizing unit and inspects presence or absence of a defect of the display panel pixel based on brightness of each image portion.

3. The display panel inspection apparatus according to claim 1,

the display device further includes a mark setting unit that sets a position at which the mark is displayed on the display panel.

4. The display panel inspection apparatus according to claim 3,

the marker setting means sets the marker at a position having a predetermined brightness or higher in both the direct image and the indirect image.

5. The display panel inspection apparatus according to claim 4,

the mark setting means reads the indirect image in units of lines parallel to a boundary between the flat surface portion and the curved portion, sets a region having a predetermined brightness or higher as a settable region, and temporarily sets the mark at a position within the settable region,

the mark setting means sets a position using the temporarily set mark when the mark appearing in the direct image is equal to or higher than the predetermined brightness when the temporarily set mark is displayed on the display panel.

6. The display panel inspection apparatus according to claim 5,

the mark setting means sets a position of a predetermined ratio from one side to the other side in parallel with a boundary between the flat surface portion and the curved portion in the settable region as a position temporarily set in the settable region.

7. A display panel inspection method for inspecting a display panel as an object to be inspected based on a direct image and an indirect image, the display panel having a flat surface portion and a curved portion that is curved on at least one side of an outer periphery of the flat surface portion, the direct image being an image of the display panel captured by an imaging means provided above, the indirect image being an image of the display panel captured via an optical system provided on a lateral side, the method comprising:

an image synthesis condition setting step of setting a synthesis condition of a direct image and an indirect image based on an image captured by the imaging means in a state where a mark parallel to a boundary between the flat surface portion and the curved portion is displayed on a display panel;

an image combining step of combining a direct image and an indirect image according to the image combining conditions set in the image combining condition setting step, based on the image captured by the imaging means in a state where the display panel is fully lit; and

and an inspection step of identifying an image portion corresponding to each pixel of the display panel in the synthesized image synthesized in the image synthesis step, and inspecting the presence or absence of a defect in the pixel of the display panel based on the luminance of each image portion.