JP6937647B2 - Optical display panel damage inspection method - Google Patents

Description

The present invention relates to an inspection method for detecting damage to an optical display panel. More specifically, the optical display panel is exposed to strong light such that the optical display panel is overexposed, and the reflected light is imaged. The present invention relates to an inspection method for reliably detecting damage caused at the edge of an 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 cracks or chips on the edges or corners of the optical display panel, cracks may occur triggered by the damaged portion. Further, in recent years, the optical display panel has been narrowed in frame, and in such a narrow frame optical display panel, a display area exists near the edge of the optical display panel. If the edge or corner of the optical display panel with a narrow frame is damaged such as cracks or chips, the damage may extend to the display area, and in such a case, the optical display panel may not be able to display normally. There is. Therefore, it is required to detect cracks and chips generated at the edges of the optical display panel without error.

The appearance inspection of the optical display panel is generally performed by irradiating the panel edge region including the edge of the optical display panel with light to capture the reflected light from the optical display panel, and performing image processing on the captured image. ing. For example, Patent Document 1 proposes a technique for inspecting the outer shape, surface, and end face of a liquid crystal panel for scratches, chips, cracks, and the like. In this technology, ring lights with a diameter larger than the outer shape of the liquid crystal panel are placed at the top, outer circumference, and bottom of the panel, and the reflected light reflected by the panel from the light emitted from these ring lights to the panel is reflected by the panel. It is captured by the imaging means arranged above. The obtained image is binarized, and scratches, chips, cracks, etc. on the liquid crystal panel can be detected from the presence or absence of a white image appearing in the binarized image.

However, in the conventional inspection technology including Patent Document 1, scattered light among the reflected light reflected from the optical display panel is captured by the imaging means, so that it is scattered from an internal pattern or the like existing near the edge of the optical display panel. Light is also photographed, and the outermost internal pattern may be erroneously detected as the edge of the optical display panel. Such false positives are particularly frequent in the case of an optical display panel having a narrow frame in which a display area exists close to the edge of the optical display panel.

Further, in the conventional inspection technique, scratches, chips, cracks, etc. of the optical display panel are detected by performing image processing such as binarization on the image obtained based on the scattered light. However, on the edge of the optical display panel, the end face is not usually neatly arranged, and there are many cases where minute irregularities are present or foreign matter or glue stains are attached. In-line inspection has been difficult with conventional techniques because advanced image processing is required to detect scratches, chips, cracks, etc. from images of such edges.

Japanese Patent Application Laid-Open No. 2003-247953

An object of the present invention is to provide an inspection method for an optical display panel, which can reliably detect only damage to the edge of an optical display panel from an image obtained based on reflected light without performing image processing. And.

An object of the present invention is to intentionally create a state in which an internal pattern is not displayed as an image by illuminating a region corresponding to the panel edge in white in an image obtained by photographing the edge of the panel including the edge of the optical display panel. , Can be solved.

The present invention provides an inspection method for inspecting damage at the edge of a panel. The inspection method according to the present invention includes a step of irradiating the irradiation light toward the edge of the panel, a step of receiving the reflected light generated by reflecting the irradiation light at the edge of the panel, and a step of receiving the received reflected light. In the image acquired based on the above, the step of detecting the contour line separating the region corresponding to the panel edge portion and the region corresponding to the background of the panel edge portion is included. The step of irradiating the irradiation light is to irradiate the acquired image with sufficient intensity to blow out the area corresponding to the panel edge so that there is no line other than the contour line in the area corresponding to the panel edge. Includes irradiating light.

In one embodiment, the reflected light generated by being reflected at the edge of the panel is preferably specularly reflected. Specular reflection light is reflected when the angle of incidence of the irradiation light emitted toward the edge of the panel with respect to the surface of the edge of the panel and the angle of reflection of the reflected light reflected from the surface of the edge of the panel are the same. It is light. In one embodiment, the brightness of the reflected light is preferably ^{3000 to 10000 cd / m 2.} In one embodiment, the irradiation light is preferably light emitted from the planar illumination.

In one embodiment, the damage inspected by the inspection method according to the present invention is preferably damage extending from one surface to the other at the edge of the panel. Further, in one embodiment, it is preferable that the acquired images are a plurality of images continuously acquired while moving the edge of the panel. Here, the two images that are back and forth in time are taken so as to partially overlap each other.

An inspection device for realizing an inspection method according to an embodiment of the present invention for inspecting damage at a panel edge is a block of an example of a polarizing film bonding device provided in a panel loading section and / or a panel unloading section. The figure is shown. The outline of the structure of the inspection apparatus which realizes the inspection method by one Embodiment of this invention, the arrangement position, and the relationship between the inspection apparatus and the flow of an optical display panel are shown. A configuration example of an inspection device that realizes an inspection method according to an embodiment of the present invention is shown. FIG. It is an entwined figure. The photographed image when the panel edge portion is irradiated with light is shown, and FIG. ) Is an example of an image taken at the edge of the panel by scattered light in the conventional inspection method. It is a flow chart which shows the method of determining the presence or absence of damage from the acquired image in the inspection method by one Embodiment of this invention.

Hereinafter, embodiments of an apparatus that realizes the inspection method according to 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 device. The optical film bonding device 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. The device 1 incorporates an inspection device for inspecting damage caused to the panel end Pe of the optical display panel P0.

In the optical film bonding device 1, the optical display panel P0 is charged from the panel charging unit 30. The charged optical display panel P0 is conveyed to the bonding unit 50 for bonding the optical film F to the optical display panel P0 via the cleaning unit 40 for cleaning foreign matter on the surface. In the bonding portion 50, the optical film F is bonded to one surface or both surfaces of the optical display panel P0, if necessary. In this embodiment, in the bonding portion 50, after the optical film F is bonded to one surface of the optical display panel P0, the optical display panel P0 moves in parallel to the adjacent transport path, and the other side of the optical display panel P0. Another optical film F is attached to the surface of the surface.

Next, the optical display panel P1 to which the optical film F is attached is carried into the pressure defoaming unit 60. In the pressure defoaming section 60, air bubbles that have entered between the pressure-sensitive adhesive and the panel surface are removed by applying uniform pressure with compressed air while heating the optical display panel P1 to which the optical film F is attached. .. The optical display panel P1 that has exited the pressure defoaming section 60 is carried out from the panel carry-out section 70.

The optical film bonding device is not limited to the one bent in the intermediate portion as shown in FIG. 1, and the panel loading portion 30 to the panel unloading portion 70 are arranged in a straight line. It may be an optical film bonding device of another form such as the device of the above.

The inspection unit 10 for carrying out the inspection method according to the present invention shall be arranged in either one or both of the panel loading unit 30 and the panel unloading unit 70, as in the inspection unit 10 shown by the dotted line in FIG. Can be done. When the inspection unit 10 is arranged in the panel loading unit 30, it is possible to mainly inspect whether or not the optical display panel P0 has already been damaged. When the inspection unit 10 is arranged in the panel loading unit 30 and the panel unloading unit 70, a factor that causes damage to the optical display panel P0 or the optical display panel P1 mainly inside the optical film bonding device 1 is a factor. You can see if it exists.

FIG. 2 shows an outline of the inspection device in the inspection unit 10 provided in the panel loading unit 30, an arrangement position, and a relationship between the inspection device and the flow of the optical display panel P0. The inspection apparatus that realizes the inspection method according to the present invention processes the images acquired by the inspection units 11a, 11b, 11c, 11d and the inspection units 11a, 11b, 11c, 11d, and moves the optical display panel P0. It includes a processing / control unit 20 that can control the timing of image acquisition according to the above. The inspection units 11a, 11b, 11c, 11d and the processing / control unit 20 may be connected by either wired communication or wireless communication (note that in FIG. 2, the drawings are not complicated so that the drawings are not complicated. A line indicating that the inspection units 11a, 11b, 11c, 11d and the processing / control unit 20 are connected by wire or wirelessly is not drawn). Further, for example, the images acquired by the inspection units 11a, 11b, 11c, and 11d may be read by the processing / control unit 20 via the physical media. The position where the processing / control unit 20 is provided is not limited, and may be provided in the optical film bonding device 1 or may be provided in a place away from the optical film bonding device 1.

The inspection units 11a, 11b, 11c, and 11d are configured to include flat illuminations 12a, 12b, 12c, and 12d, and area cameras 13a, 13b, 13c, and 13d, respectively. The light source of the flat illuminations 12a, 12b, 12c, and 12d is preferably, but is not limited to, an LED. In the embodiment shown in FIG. 2, the inspection units 11a and 11b can inspect the panel edges Pea and Peb in the long side regions 14a and 14b of the optical display panel P0 inserted into the panel loading unit 30. Arranged like this. Further, the inspection units 11c and 11d are arranged so that damage to the panel edges Pec and Ped in the short side regions 14c and 14d of the optical display panel P0 can be inspected after the panel edges Pea and Peb are inspected. Will be done. The optical display panel P0, which has been inspected by the inspection units 11c and 11d, has the identification mark 15 read by using an imaging device (not shown) or the like as necessary, and the information of the optical display panel P0 specified by the identification mark 15 is obtained. It is linked 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, change the traveling direction of the optical display panel P0 by 90 °, and then inspect the inspection unit. 11c, 11d are configured to inspect the short side regions 14c, 14d. However, the method is not limited to such an inspection method. For example, the transport path of the optical display panel P0 in the panel loading unit 30 is made linear, and the inspection units 11a and 11c and the inspection units 11b and 11d are respectively. After arranging the optical display panel P0 along the transport path, first inspecting the long side regions 14a and 14b of the optical display panel P0 by the inspection units 11a and 11b, and rotating the orientation of the optical display panel P0 by 90 °. The inspection units 11c and 11d may be configured to inspect 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 here, in FIG. 2, the optical display panel P0 is arranged to inspect the long side region 14a on the right side in the transport direction. A configuration example of the inspection unit 11a is shown. The inspection units 11b, 11c, and 11d can also have the same configuration as the inspection unit 11a. FIG. 3A is a view of the optical display panel P0 and the inspection unit 11a from above, and FIG. 3B is a side surface of the optical display panel P0 and the inspection unit 11a (upstream side in the transport direction of the optical display panel P0). ).

As shown in FIG. 3, the inspection unit 11a includes a flat illumination 12a and an area camera 13a. When viewed from the upper surface as shown in FIG. 3A, the flat illumination 12a is arranged outside the end portion Pe of the optical display panel P0 to be conveyed, and the area camera 13a is the optical display panel P0. It is preferably arranged inward from the end Pe. In another embodiment, the flat illumination 12a may be arranged inside the end Pe of the optical display panel P0 to be conveyed, and the area camera 13a may be arranged outside the end Pe of the optical display panel P0. However, the arrangement shown in FIG. 3A is more preferred from the viewpoint of more accurate detection of panel edges Pea, Peb, Pec, and Ped. As shown in FIG. 3B, the planar illumination 12a is oriented such that the illumination light Le is radiated toward the region 14a including the end Pe of the optical display panel P0. The irradiation light Le is reflected by the panel end portion Pe of the optical display panel P0, and is incident on 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 according to the present invention, the irradiation light so that the reflected light Lr from the panel end Pe includes only the light reflected from the surface of the panel end Pe, not the light reflected inside the panel end Pe. The intensity of Le and / or the angle of incidence of the panel edge Pe on the surface is set. The state in which the reflected light Lr contains only the light reflected from the surface of the panel end Pe, not the light reflected by the internal pattern or the like existing at the panel end Pe, is found in the internal pattern of the panel end Pe or the like. Not only when the reflected light is not included in the reflected light Lr at all, but also 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 obtained by capturing the reflected light Lr. The reflected light Lr also includes the case where the light reflected by the internal pattern of the end portion Pe or the like is included. The reflected light Lr was imaged so that the reflected light Lr from the panel end Pe includes only the light reflected from the surface of the panel end Pe, not the light reflected in the internal pattern of the panel end Pe. The irradiation light Le is emitted from the flat illumination 12a with sufficient intensity to blow out the region corresponding to the panel edge Pe of the image.

In one embodiment, the incident angle of the irradiation light Le from the flat illumination 12a (the angle between the normal line of the surface of the panel end Pe which is the reflection surface and the irradiation light Le) and the reflection at the panel end Pe. It is preferable that the reflected angle of the reflected light Lr (the angle between the normal surface of the surface of the panel end Pe and the reflected light Lr) is the same angle θ. The reflected light Lr reflected at the same angle as the incident angle of the irradiation light Le is called a regular reflected light or a specular reflected light, and the reflected light Lr is not the light reflected by the internal pattern of the panel end Pe, but the panel. Only the light reflected from the surface of the edge Pe is included. Brightness of the reflected light Lr is preferably 3000~10000cd / ^{m 2,} more preferably from 3500~9500cd / ^{m 2,} further preferably 3600~9100cd / ^{m 2.}

FIG. 4 shows a comparison between the image (a) taken by the inspection method according to the present invention and the image (b) taken by the conventional inspection method. In the conventional inspection method, scattered light in the region 14a including the panel edge Pe is photographed. As shown in FIG. 4, in the image (a) taken by the inspection method according to the present invention, the region corresponding to the panel edge Pe is overexposed, and the region corresponding to the background of the panel edge Pe is expressed. Since bk is expressed in black, the contour line that separates 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 displayed. On the other hand, in the image (b) taken by the conventional inspection method, a pattern or the like existing inside the panel end Pe is taken in the area corresponding to the panel end Pe, so that the panel end Pe and the background It becomes difficult to distinguish between the contour line that separates bk and the line such as the internal pattern, and it is difficult to accurately detect the panel edge Pea.

As described above, the inspection method according to the present invention detects a contour line that separates the panel edge Pe and the background from the acquired image, and occurs on the panel edges Pea, Peb, Pec, and Ped from the state of the contour line. It determines the presence or absence of damage. Therefore, the damage detected is preferably damage extending from one surface to the other at the edge of the panel.

Referring again to FIG. 3, the inspection unit 11a preferably includes rails 16a, 16b, and 16c for separately moving the planar illumination 12a and the area camera 13a in the vertical and horizontal directions. The planar illumination 12a can be moved along the rail 16a in the direction indicated by the arrow h1 in FIG. 3, and the area camera 13a can be moved along the rail 16b in the direction indicated by the arrow h2 in FIG. be able to. Further, the rail 16a and the rail 16b can be moved along the rail 16c in the directions indicated by arrows h3 and h4, respectively.

It is preferable that the flat illumination 12a is connected to the rail 16a via the shaft 121a, and the area camera 13a is connected to the rail 16b via the shaft 131a. The planar illumination 12a is rotatable around the axis 121a in the direction indicated by arrow r1, and the area camera 13a is rotatable around the axis 131a in the direction indicated by arrow r2. In this way, the plain illumination 12a and the area camera 13a can independently adjust the vertical position, the distance between them, the irradiation angle of the irradiation light, and the reception angle of the reflected light. Depending on the size and type of the optical display panel P0, the position and angle can be appropriately determined so that the area corresponding to the edge of the panel of the captured image can be overexposed.

In the inspection method according to the present invention, for example, the method of adjusting the position and angle of the flat illumination 12a and the area camera 13a so that the area corresponding to the panel edge Pe of the captured image can be overexposed is as follows. It is as follows. First, the position and angle of the area camera 13a are adjusted so that the panel end Pe is in 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, the focus of the area camera 13a is adjusted with the aperture of the area camera 13a stopped down. After the area camera 13a is focused on the panel edge Pe, the aperture is opened.

Next, while considering the position and angle of the area camera 13a, the angle at which the irradiation light Le from the flat illumination 12a is incident on the surface of the panel end Pe, and the reflected light Lr reflected from the surface of the panel end Pe. The position and angle of the flat illumination 12a are adjusted so that the angles are substantially equal to each other and 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. Further, while checking the captured image on a monitor or the like, the position and angle of the flat illumination 12a are finely adjusted so that the panel edge Pe is overexposed.

FIG. 5 is a flow chart showing an example of a method for determining the presence or absence of damage to the panel end Pe from the acquired image in the inspection method according to the present invention. Damage can be determined, for example, as follows. First, in the captured image, the brightness of each pixel is acquired. Based on the acquired brightness, a set of pixels having a brightness difference of a predetermined threshold value or more between adjacent pixels is detected. Multiple sets of pixels are detected. The threshold value at this time can be appropriately set according to conditions such as the type of panel and the type of light source. In each of the detected pixel sets, the boundary between the high-brightness pixel and the low-brightness pixel is found, and the line connecting the boundaries extracted at predetermined intervals is the contour line that separates the panel edge Pe and the background, that is, Recognized as panel edge Pea, Peb, Pec, Ped.

Next, the recognized region is searched along the panel edges Pea, Peb, Pec, and Ped, and the brightness of the pixels recognized as the panel edges Pea, Peb, Pec, and Ped is acquired. In the searched area, a pixel recognized as a panel edge Pea, Peb, Pec, or Ped and a pixel having a brightness difference of a predetermined threshold value or more are detected. If there is a portion having a brightness difference of a size equal to or larger than a predetermined size, it is determined that the optical display panel P0 is damaged. The threshold value and size of the luminance difference at this time can be appropriately set according to the permissible size of damage to be detected and the like.

In the inspection method according to the present invention, there is a method of continuously photographing the panel end Pe so that a part of the images captured before and after the time is overlapped while moving the conveyed optical display panel P0. It is preferable to be used. In this method, the processing / control unit 20 controls the timing of acquiring an image according to the moving speed of the panel end portion Pe passing below the area cameras 13a, 13b, 13c, and 13d.

Specifically, the timing of acquiring an image is set to a part corresponding to the rear part of the image acquired earlier in the transport direction and a part corresponding to the front part of the image acquired next in the transport direction. The same part of the panel edge Pe is set to be imaged. The area of the overlapping portion can be appropriately set as needed. In this way, by continuously photographing the panel edge Pe in the captured image so as to partially overlap in the transport direction, the entire panel edge Pe can be imaged without exception. Therefore, the panel edge Pea , Peb, Pec, Ped can improve the detection accuracy of damage.

In another embodiment, a line camera may be used as the image pickup apparatus for the inspection units 11a, 11b, 11c, and 11d instead of the area camera. When a line camera is used, 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 edge Pea, Peb, Pec, Ped Panel edge P1 Optical film bonded Optical display panel 1 Optical film bonding device 10 Inspection unit 11a, 11b, 11c, 11d Inspection unit 12a, 12b, 12c, 12d Flat optics 13a, 13b, 13c, 13d Area cameras 16a, 16b, 16c Moving rails 14a, 14b, 14c, 14d Inspection area 20 Processing / control unit 15 Identification mark 30 Panel insertion unit 40 Cleaning unit 50 Laminating unit 60 Pressurized defoaming part 70 Panel carry-out part

Claims (6)

An inspection method for inspecting damage to the edge of an optical display panel.
The process of irradiating the irradiation light toward the edge of the panel,
A step of receiving the reflected light generated by reflecting the irradiation light at the edge of the panel, and
In the image acquired based on the received reflected light, the step of detecting the contour line separating the region corresponding to the panel edge portion and the region corresponding to the background of the panel edge portion is included.
The step of irradiating the irradiation light is sufficient to blow out the area corresponding to the panel edge so that the area corresponding to the panel edge does not have a line other than the contour line in the acquired image. only contains the irradiating the irradiation light with such intensity,
The reflected light is specularly reflected light,
The angle of incidence of the irradiation light on the panel edge in the step of irradiating the irradiation light is equal to the angle of reflection of the reflected light from the panel edge in the step of receiving the reflected light.
Inspection method.
The light source that irradiates the irradiation light is arranged outside the panel edge, and the image pickup device that receives the reflected light is arranged inside the panel edge, or the light source that irradiates the irradiation light is the panel. The inspection method according to claim 1, wherein an imaging device that is arranged inward from the end and receives reflected light is arranged outside from the end of the panel. The inspection method according to claim 1 or ² , wherein the brightness of the reflected light is 3000 to 10000 cd / m 2. The inspection method according to any one of claims 1 to 3, wherein the damage detected is damage extending from one surface to the other at the edge of the panel. The acquired image is a plurality of images continuously acquired while moving the edge of the panel, and the two images that are back and forth in time are captured so that a part of each image overlaps. , The inspection method according to any one of claims 1 to 3. The inspection method according to any one of claims 1 to 3, wherein the irradiation light is light emitted from a flat type illumination.

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