TWI779055B - Damage inspection method of optical display panel - Google Patents

Abstract

[Problem] To provide an inspection method of an optical display panel capable of reliably detecting only damage to an edge portion of an optical display panel from an image obtained by reflected light without performing image processing. [Solution] The inspection method of the present invention includes: a process of irradiating the irradiated light to the edge of the panel; a process of receiving reflected light generated by reflecting the irradiated light at the edge of the panel; In the image, the process of delineating the outline of the area corresponding to the edge of the panel and the area corresponding to the background of the edge of the panel is detected. The process of irradiating the light includes: irradiating the light with sufficient intensity to whiten the area corresponding to the edge of the panel, so that there are no lines other than the outline in the area corresponding to the edge of the panel in the acquired image.

Description

Damage inspection method of optical display panel

The present invention relates to an inspection method for detecting damage to an optical display panel, and more specifically, relates to an inspection method by irradiating the optical display panel with strong light to the extent of blown out highlights and taking an image of the optical display panel. This reflected light is an inspection method for reliably detecting damage generated at the edge of the optical display panel.

In an optical display panel such as a liquid crystal display panel or an organic EL display panel, if there is damage such as a crack or a defect at an edge or a corner of the optical display panel, there is a risk of cracking at the damaged portion. In addition, in recent years, with the progress of narrowing the frame of the optical display panel, in such a narrow-frame optical display panel, a display area exists until the edge of the optical display panel. If damage such as cracks or defects occurs on the edges or corners of the narrow-frame optical display panel, the damage will extend to the display area. In this case, the optical display panel may not be able to display normally. Therefore, it is required to detect cracks or defects generated at the edge of the optical display panel without fail.

The appearance inspection of the optical display panel is generally performed by irradiating light to the panel end region including the edge of the optical display panel, photographing the reflected light from the optical display panel, and applying image processing to the photographed image. For example, Patent Document 1 proposes a technique for inspecting the appearance, surface, and end faces of a liquid crystal panel for flaws, defects, cracks, and the like. This technology is to arrange ring-shaped lighting with a diameter larger than the outer shape of the liquid crystal panel on the upper part, outer periphery and lower part of the panel, and obtain images irradiated from the ring-shaped lighting to the panel by means of an imaging mechanism arranged directly above the panel. Reflected light where the light is reflected by the panel. The obtained image is subjected to binarization processing, and based on the presence or absence of white images appearing in the binarized image, it is possible to detect flaws, defects, cracks, etc. of the liquid crystal panel.

However, in the conventional inspection technology including Patent Document 1, since scattered light is obtained from the reflected light reflected by the optical display panel by the imaging mechanism, light from a position close to the edge of the optical display panel is also photographed. Scattered light from internal patterns and the like may mistakenly detect the outermost internal pattern as the edge of the optical display panel. Such erroneous detection often occurs particularly in the case of an optical display panel with a narrow frame that exists in a display area near the edge of the optical display panel.

Also, in the conventional inspection technology, for obtaining an image based on scattered light, for example, image processing such as binarization is performed to detect flaws, defects, cracks, etc. of the optical display panel. However, at the edge of the optical display panel, generally, the end surface is not smooth, and there are often tiny bumps, foreign objects or glue stains. In order to detect flaws, defects, cracks, etc. from edge images such as photography, it is difficult to perform online inspections in the conventional technology because advanced image processing is required. [Prior Art Document] [Patent Document]

[Patent Document 1] Japanese Patent Laid-Open No. 2003-247953

[Problem to be solved by the invention]

An object of the present invention is to provide an inspection method of an optical display panel capable of reliably detecting only damage to the edge of an optical display panel from an image obtained by reflected light without performing image processing. [means to solve the problem]

The problem of the present invention is to solve the problem by brightening the area corresponding to the edge of the panel and intentionally creating a state where the internal pattern is not displayed as an image when taking an image of the edge of the panel including the edge of the optical display panel. .

The invention provides an inspection method for inspecting the damage of the panel end in the optical display panel. The inspection method of the present invention includes: a process of irradiating the irradiated light to the edge of the panel; a process of receiving reflected light generated by reflecting the irradiated light at the edge of the panel; and inspecting the image obtained based on the received reflected light The process of drawing the outline of the area corresponding to the edge of the panel and the area corresponding to the background of the edge of the panel. The process of irradiating the light includes: irradiating the light with sufficient intensity to make the area corresponding to the edge of the panel blown out highlights, so that there are no lines other than the outline in the area corresponding to the end of the panel in the acquired image .

In one embodiment, it is preferable that the reflected light generated by reflection at the edge of the panel is regular reflected light. The regular reflected light is reflected light when the incident angle of the irradiated light irradiated to the panel end surface is the same angle as the reflection angle of the reflected light reflected from the panel end surface with respect to the panel end surface. In one embodiment, the luminance of reflected light is preferably 3000-10000 cd/m ² . In one embodiment, the irradiation light is preferably light emitted from a planar illumination.

In one embodiment, the damage inspected by the inspection method of the present invention is preferably damage at the edge of the panel and from one side to the other. In addition, in one embodiment, it is preferable that the acquired images are plural images acquired continuously while moving the panel edge. Among them, the two images whose time is front and rear are captured so as to partially overlap each other.

Hereinafter, embodiments of an apparatus for realizing the inspection method of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of an example of an optical film bonding apparatus. The optical film bonding apparatus 1 shown in FIG. 1 is a device for bonding an optical film F such as a polarizing film or a retardation film to an optical display panel P0 such as a liquid crystal panel, for example. In this apparatus 1, the inspection apparatus which inspects the damage which arises in the panel edge part Pe of the optical display panel P0 is incorporated.

In the optical film bonding apparatus 1, the optical display panel P0 is injected|thrown-in from the panel input part 30. FIG. The input optical display panel P0 is conveyed to the bonding part 50 for bonding the optical film F to the optical display panel P0 via the cleaning part 40 for cleaning the foreign matter on the surface. In the bonding part 50, the optical film F is bonded to one surface or both surfaces of the optical display panel P0 as needed. In this embodiment, after the optical film F is bonded to one side of the optical display panel P0 in the bonding unit 50, the optical display panel P0 is moved in parallel to the adjacent conveyance path, and another film F is bonded to the other surface of the optical display panel P0. The optical film F.

Next, the optical display panel P1 to which the optical film F was bonded is carried into the pressure defoaming part 60 . In the pressure defoaming unit 60 , while heating the optical display panel P1 bonded with the optical film F, uniform pressure is applied by compressed air to remove air bubbles that entered between the adhesive and the panel surface. The optical display panel P1 separated from the pressure defoaming unit 60 is carried out from the panel carry-out unit 70 .

In addition, the optical film laminating apparatus is not limited to the form shown in FIG. 1 that is bent at the middle part, and other forms of optical films such as a device that is arranged in a linear form from the panel input part 30 to the panel output part 70 Fitted devices are also available.

The inspection unit 10 for carrying out the inspection method of the present invention can be disposed in either or both of the panel carrying-in unit 30 and the panel carrying-out unit 70 as shown by the broken line in FIG. 1 . When the inspection unit 10 is arranged in the panel loading unit 30, it is mainly possible to inspect whether or not damage has occurred on the optical display panel P0. When the inspection part 10 is arrange|positioned in the panel input part 30 and the panel carry-out part 70, whether there exists the factor which damages the optical display panel P0 or the optical display panel P1 inside the optical film bonding apparatus 1 can be grasped mainly.

FIG. 2 shows the outline of the inspection device provided in the inspection unit 10 of the panel loading unit 30 , its arrangement position, and the relationship between the inspection device and the flow of the optical display panel P0 . The inspection device for implementing the inspection method of the present invention includes: inspection units 11a, 11b, 11c, 11d, and while processing the images obtained by the inspection units 11a, 11b, 11c, 11d, it can respond to the optical display panel P0 The moving speed controls the processing/controlling unit 20 at the timing of video acquisition. The inspection units 11a, 11b, 11c, 11d and the processing/control unit 20 can be connected by any one of wired communication or wireless communication (in addition, in FIG. 11a, 11b, 11c, 11d and the processing/control unit 20 are connected by wire or wireless). Also, for example, the images obtained by the inspection units 11a, 11b, 11c, and 11d may be read by the processing/control unit 20 via a physical medium. The position where the process/control part 20 is installed is not limited, It may be installed in the optical film bonding apparatus 1, and may be installed in the place far from the optical film bonding apparatus 1.

The inspection units 11a, 11b, 11c, and 11d are composed of planar lights 12a, 12b, 12c, and 12d, and area cameras 13a, 13b, 13c, and 13d, respectively. The light sources of the planar lighting 12a, 12b, 12c, and 12d are preferably LEDs, but not limited thereto. In the embodiment shown in FIG. 2 , the inspection units 11a, 11b are arranged so as to be able to inspect the damage of the panel edges Pea, Peb in the long side regions 14a, 14b of the optical display panel P0 loaded into the panel loading unit 30 . In addition, the inspection units 11c and 11d are disposed so as to inspect the damage of the panel edges Pec and Ped in the short side regions 14c and 14d of the optical display panel P0 after inspecting the panel edges Pea and Peb. After the inspection of the inspection units 11c and 11d is completed, the optical display panel P0 reads the identification mark 15 by using an imaging device not shown in the figure as necessary, and links the information of the optical display panel P0 specified by the identification mark 15 with the inspection result.

In the embodiment shown in FIG. 2, the inspection units 11a and 11b first inspect the long side regions 14a and 14b of the optical display panel P0, and after changing the running direction of the optical display panel P0 by 90°, the inspection units 11c and 11d inspect the short regions. The side regions 14c, 14d are configured in a manner. However, it is not limited to such an inspection method. For example, the conveyance path of the optical display panel P0 in the panel input part 30 is made linear, and the inspection units 11a and 11c, and the inspection units 11b and 11d are respectively arranged along the Arranged along the transport path of the optical display panel P0, the long side regions 14a, 14b of the optical display panel P0 are initially inspected by the inspection units 11a, 11b, and the direction of the optical display panel P0 is rotated by 90°, and then the inspection unit 11c, 11d is also possible to check the short side regions 14c and 14d.

FIG. 3 shows a configuration example of a set of inspection devices arranged in the inspection unit 10, and shows a configuration example of the inspection unit 11a arranged to inspect the long side region 14a on the right side of the transport direction of the optical display panel P0 in FIG. 2. The inspection units 11b, 11c, and 11d may have the same configuration as the inspection unit 11a. 3( a ) is a view of the optical display panel P0 and the inspection unit 11a viewed from above, and FIG. 3( b ) is a view of the optical display panel P0 and the inspection unit 11a viewed from the side (upstream side in the transport direction of the optical display panel P0 ). .

As shown in FIG. 3 , the inspection unit 11a includes a planar illuminator 12a and an area camera 13a. As shown in FIG. 3( a ), when viewed from above, the planar lighting 12a is disposed outside the end Pe of the optical display panel P0 being conveyed, and the area camera 13a is disposed further outside the end Pe of the optical display panel P0. More medial is better. In another embodiment, although the planar lighting 12a can be arranged inside the end Pe of the optical display panel P0 being conveyed, the area camera 13a can be arranged outside the end Pe of the optical display panel P0. , but from the point of view of high-precision detection of panel edges Pea, Peb, Pec, and Ped, the configuration shown in FIG. 3(a) is better. As shown in FIG. 3( b ), the direction of the planar illumination 12 a is such that the irradiation light Le is radiated toward the region 14 a including the end Pe of the optical display panel P0 . The irradiation light Le is reflected by the panel end Pe of the optical display panel P0, and enters the area camera 13a as reflected light Lr. The reflected light Lr incident on the area camera 13a is incident on the light receiving element of the area camera 13a, and is sent to the processing/control unit 20 as an image of a predetermined area including the panel end Pe and its background.

In the inspection method of the present invention, the irradiation light Le is set so that the reflected light Lr from the panel end Pe does not include the light reflected inside the panel end Pe but includes only the light reflected from the surface of the panel end Pe. The intensity and/or the incident angle to the surface of the panel end Pe. In addition, the reflected light Lr does not include the light reflected by the internal patterns existing at the panel end Pe, but only includes the light reflected from the surface of the panel end Pe, not only the state that the reflected light Lr does not include the light reflected by the panel at all. The light reflected by the internal pattern of the end portion Pe also includes the reflected light Lr to the extent that it does not affect the determination of the presence or absence of damage to the panel edges Pea, Peb, Pec, and Ped in the image of the captured reflected light Lr. The state of the light reflected by the internal pattern of the panel end Pe. In order to make the reflected light Lr from the panel end Pe not include the light reflected by the internal pattern of the panel end Pe but only the light reflected from the surface of the panel end Pe, the image corresponding to the reflected light Lr is captured. The region of the panel end Pe is white-jumped with sufficient intensity to irradiate the illumination light Le from the planar illumination 12a.

In one embodiment, the incident angle of the irradiated light Le from the planar lighting 12a (the angle between the normal line of the reflective surface, that is, the surface of the panel end Pe and the irradiated light Le), the reflected light reflected by the panel end Pe The reflection angle of Lr (the angle between the normal to the surface of the panel end Pe and the reflected light Lr) is preferably the same angle θ. The reflected light Lr reflected at the same angle as that of the irradiated light Le is called regular reflected light or specularly reflected light, and the reflected light Lr does not include the light reflected from the internal pattern of the panel edge Pe but only the light reflected from the panel end Pe. The light reflected from the surface of the end Pe. The luminance of the reflected light Lr is preferably 3,000 to 10,000 cd/m ² , more preferably 3,500 to 9,500 cd/m ² , and still more preferably 3,600 to 9,100 cd/m ² .

Fig. 4 shows a comparison between an image (a) captured by the inspection method of the present invention and an image (b) imaged by the conventional inspection method. In the conventional inspection method, scattered light including the Pe region 14 a at the edge of the panel is photographed. As shown in FIG. 4 , in the image (a) captured by the inspection method of the present invention, since the region corresponding to the panel edge Pe is expressed in white, the region bk corresponding to the background of the panel edge Pe is displayed in black. To be represented, the contour line dividing the region corresponding to the panel edge Pe and the region corresponding to the background of the panel edge Pe, that is, the panel edge Pea is clearly expressed. On the other hand, in the image (b) captured by the conventional inspection method, since a pattern or the like existing inside the panel end Pe is captured in an area corresponding to the panel end Pe, the panel end Pe is divided. It becomes difficult to distinguish the contour line from the background bk from lines such as internal patterns, and it is difficult to detect the panel edge Pea with high accuracy.

Therefore, the inspection method of the present invention detects the contour line dividing the panel edge Pe and the background from the obtained image, and judges whether damage occurs on the panel edges Pea, Peb, Pec, and Ped from the state of the contour line. Therefore, the detected damage is at the end of the panel, and from one side to the other.

Referring to FIG. 3 again, the inspection unit 11a preferably has rails 16a, 16b, and 16c for moving the planar lighting 12a and the area camera 13a in the vertical direction and the horizontal direction, respectively. The planar lighting 12a can move along the rail 16a in the direction indicated by the arrow h1 in FIG. 3 , and the area camera 13a can move along the rail 16b in the direction indicated by the arrow h2 in FIG. 3 . In addition, the rail 16a and the rail 16b are movable in directions indicated by arrows h3 and h4, respectively, along the rail 16c.

The planar lighting 12a is connected to the rail 16a through the shaft 121a, and the area camera 13a is preferably connected to the rail 16b through the shaft 131a. The planar lighting 12a can rotate around the axis 121a in the direction indicated by the arrow r1, and the area camera 13a can rotate around the axis 131a in the direction indicated by the arrow r2. In this way, the planar lighting 12a and the area camera 13a can independently adjust the position in the vertical direction, the distance between them, the irradiation angle of the irradiating light, and the receiving angle of the reflected light. Therefore, it is possible to adapt to the size and type of the optical display panel P0 , set the position and angle appropriately, so that the area corresponding to the edge of the panel of the photographed image jumps.

In the inspection method of the present invention, the method of adjusting the position and angle of the planar illuminator 12a and the area camera 13a so that the area corresponding to the panel end Pe of the imaged image jumps is as follows, for example. First, the position and angle of the area camera 13a are adjusted so that the panel end Pe enters the field of view of the area camera 13a. This adjustment can be performed by changing the positions in the directions of h2 and h4 and the rotation angle of r2. Next, focus adjustment of the area camera 13a is performed with the aperture of the area camera 13a being stopped down. After the focus of the area camera 13a matches the panel end Pe, the diaphragm is opened.

Next, while considering the position and angle of the area camera 13a, the angle at which the irradiation light Le from the planar lighting 12a is incident on the surface of the panel end Pe and the angle of the reflected light Lr reflected from the surface of the panel end Pe are adjusted. The angles are substantially equal, and the position and angle of the planar lighting 12a are adjusted so that the entire panel edge Pe is irradiated with light as uniformly as possible. This adjustment can be performed by changing the positions in the directions of h1 and h3 and the rotation angle of r1. Next, while checking the captured video on a monitor or the like, the position and angle of the planar lighting 12a are finely adjusted so that the panel edge Pe is white-jumped.

FIG. 5 is a flowchart showing an example of a method for judging the presence or absence of damage to the panel edge Pe from the acquired image in the inspection method of the present invention. Damage can be determined as follows, for example. First, in the captured image, the luminance of each pixel is obtained. Based on the obtained luminance, a group of pixels having a luminance difference equal to or greater than a predetermined threshold value is detected among adjacent pixels. Checks out the set of pluralities for this pixel. The threshold at this time can be appropriately set according to conditions such as the type of panel and the type of light source. In each group of detected pixels, the boundary between the high-intensity pixel and the low-intensity pixel is found, and the line connecting the boundary extracted at a predetermined interval is used as the boundary between the end Pe of the sub-panel and the background. Contour lines, that is, panel edges Pea, Peb, Pec, Ped to identify.

Next, the recognized regions are searched along the panel edges Pea, Peb, Pec, and Ped, and the luminances of the pixels recognized as the panel edges Pea, Peb, Pec, and Ped are acquired. In the searched area, pixels having a luminance difference equal to or greater than a predetermined threshold value from pixels recognized as panel edges Pea, Peb, Pec, and Ped are detected. If there is a place where a difference in luminance occurs in a size greater than or equal to a predetermined size, it is determined that damage exists in the optical display panel P0. The threshold value and size of the luminance difference at this time can be appropriately set in accordance with the allowable size of the damage to be detected and the like.

In the inspection method of the present invention, it is preferable to use a method of continuously photographing the panel end Pe so that part of the imaged images are overlapped in time while moving the conveyed optical display panel P0. In this method, the processing/control unit 20 controls the timing of acquiring images according to the moving speed of the panel end Pe passing below the area cameras 13a, 13b, 13c, and 13d.

Specifically, the timing of acquiring an image is determined by the same portion corresponding to a portion of the rear portion of the transport direction of the image acquired earlier in time and a portion of the same portion of the end portion Pe of the imaging panel corresponding to the front of the transport direction of the image acquired next. mode setting. The area of the overlapping portion can be appropriately set as necessary. In this way, by continuously photographing the captured image of the panel end Pe in a manner that partially overlaps in the conveyance direction, the entire panel end Pe can be imaged without omission, and the detection of the edge Pea and Peb occurring at the panel edge can be improved. , Pec, Ped damage accuracy.

In addition, in another embodiment, instead of an area camera, a line camera may be used as the imaging device of the inspection units 11a, 11b, 11c, and 11d. When using a line camera, the image of the panel end Pe of the optical display panel P0 can be acquired as a continuous image.

P0‧‧‧optical display panel Pe‧‧‧panel end Pea, Peb, Pec, Ped‧‧‧panel edge P1‧‧‧optical display panel with optical film bonded 1‧‧‧optical film bonding device 10‧ ‧‧Inspection parts 11a, 11b, 11c, 11d Use rails 14a, 14b, 14c, 14d‧‧‧inspection area 20‧‧‧processing/control part 15‧‧‧identification mark 30‧‧‧panel input part 40‧‧‧cleaning part 50‧‧‧bonding part 60 ‧‧‧Pressure defoaming part 70‧‧‧Panel carrying out part

[FIG. 1] A configuration area showing an example of a polarizing film laminating device installed in a panel loading section and/or a panel carrying out section. block diagram. [FIG. 2] It shows the outline of the structure of the inspection apparatus which implements the inspection method of one embodiment of this invention, arrangement|positioning, and the relationship of the flow of an inspection apparatus and an optical display panel. [ Fig. 3] Fig. 3 shows a configuration example of an inspection device for realizing an inspection method according to an embodiment of the present invention, (a) is a view of the optical display panel and the inspection unit viewed from above, and (b) is a view of the optical display panel and the inspection unit viewed from the side. A diagram of the unit. [ Fig. 4 ] shows a photographed image when light is irradiated to the edge of the panel, (a) is an example of a photographed image of the edge of the panel caused by regular reflected light photographed in the inspection method according to an embodiment of the present invention, ( b) is an example of a photographed image of the edge of the panel due to scattered light in the conventional inspection method. [FIG. 5] A flowchart showing a method of judging the presence or absence of damage from acquired images in the inspection method according to an embodiment of the present invention.

P0‧‧‧Optical Display Panel

Pea, Peb, Pec, Ped‧‧‧panel edge

10‧‧‧Inspection Department

11a, 11b, 11c, 11d‧‧‧inspection unit

12a, 12b, 12c, 12d‧‧‧plane lighting

13a, 13b, 13c, 13d‧‧‧area camera

14a, 14b‧‧‧long side area

14c, 14d‧‧‧Short side area

15‧‧‧Identification

20‧‧‧Processing/Control Department

30‧‧‧Panel input part

40‧‧‧Cleaning Department

Claims (6)

An inspection method for inspecting damage to an end portion of a panel in an optical display panel, comprising: a process of irradiating light to the end of the panel; a process of receiving reflected light generated by reflecting the irradiated light at the end of the panel; In the image obtained based on the received reflected light, the process of detecting the contour line of the region corresponding to the edge of the panel and the region corresponding to the background of the edge of the panel is detected; wherein, the process of irradiating the irradiating light includes: Irradiate with sufficient intensity to make the area corresponding to the end of the panel blown out highlights, so that in the obtained image, there is no line other than the outline in the area corresponding to the end of the panel; the reflected light is Regularly reflected light: the incident angle of the irradiated light to the end of the panel in the process of irradiating the irradiated light is equal to the reflection angle of the reflected light from the end of the panel in the process of receiving the reflected light. The inspection method described in claim 1, wherein the light source for irradiating the irradiation light is arranged outside the edge of the panel and the imaging device for receiving the reflected light is arranged inside the edge of the panel, or the light source for emitting the irradiation light The camera device that is placed further inside than the edge of the aforementioned panel and receives reflected light Placed further outside than the end of the panel. The inspection method described in claim 1, wherein the luminance of the reflected light is 3000 to 10000 cd/m ² . The inspection method described in any one of claim 1 to claim 3, wherein the detected damage is the damage at the end of the panel and from one side to the other side. The inspection method described in any one of claim 1 to claim 3, wherein the acquired image is a plurality of images acquired continuously while moving the edge of the panel, and the two images before and after the time are respectively The person is captured in a partially overlapping manner. The inspection method according to any one of claim 1 to claim 3, wherein the irradiation light is light radiated from a planar illumination.

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