Patent Application
20190279545
This application claims priority from Japanese Patent Application No. 2018-042741 filed on Mar. 9, 2018. The entire contents of the priority application are incorporated herein by reference.
The technology described herein relates to a system of inspecting a display panel that, in a process of producing a display device, conducts an inspection of a display panel included in the display device, and relates also to a display panel inspection method of inspecting a display panel.
In a process of producing various display devices, such as a liquid crystal display, a plasma display, and an organic EL display, an inspection to see whether a display panel included in a display device is normal, more specifically, an inspection to see whether the display panel is lighted on normally is conducted. A lighting defect of the display panel is caused by a defect in the display panel. For example, lighting defects may be caused by a damage to the display panel, disconnection of scanning lines or signal lines, a line defect resulting from short circuit, mixture of impurity into the display panel during a molding process, or the like. Methods of detecting a lighting defect of a display panel are known. Those methods include a method of detecting a lighting defect based on an image captured by an image-capturing device (microscope) and a method of detecting a lighting defect based on image data created by processing incoming reflection light from the surface of the display panel on which light is emitted. However, these methods, by which a lighting defect of the display panel is detected through image processing, may lead to a case where foreign matter, such as dust and dirt, deposited on the surface of the display panel is determined also to be a lighting defect. Examples of these methods are disclosed in Japanese Unexamined Patent Application Publication No. 2009-155158 and Japanese Unexamined Patent Application Publication No. H10-19734.
Techniques of dealing with such a lighting defect caused by foreign matter have been proposed. For example, in Japanese Unexamined Patent Application Publication No. 2009-155158, an operator determines whether it is a foreign matter based on a magnified image captured by a microscope and when determining that foreign matter is deposited on the display panel, the foreign matter is removed. Japanese Unexamined Patent Application Publication No. H10-19734 describes a technique of checking a display panel to see whether a foreign matter is deposited thereon before conducting an inspection of the display panel and, upon finding the foreign matter on the display panel, removing the foreign matter.
According to the technique described in Japanese Unexamined Patent Application Publication No. 2009-155158, the operator has to find out whether any foreign matter is deposited on the display panel and could make an error in determining the presence/absence of a foreign matter. Since the operator has to check several spots to see whether foreign matter is present there, inspection time becomes longer. According to the technique described in Japanese Unexamined Patent Application Publication No. H10-19734, before an inspection of the display panel is conducted, determination of whether foreign matter is deposited on the display panel must be made first. This also leads to a problem of a longer inspection time.
The technology described herein was made in view of the above circumstances. An object is to provide a system of inspecting a display panel and a method of inspecting a display panel, the system and the method allowing an inspection of a display panel to be conducted accurately and efficiently.
A system of inspecting a display panel according to the technology described herein conducts an inspection of a display panel included in a display device in a process of producing the display device. The system includes an inspection apparatus and a cleaner configured to clean a surface of the display panel. The inspection apparatus is configured to obtain an image of the display panel relating a lighting condition thereof and process the image and determine whether the display panel has a lighting defect. If determining that the display panel has a lighting defect, the inspection apparatus is configured to obtain lighting defect information relating the lighting defect, store the lighting defect information, and make the cleaner to clean at least a portion of the display panel having the lighting defect. The inspection apparatus is configured to determine presence or absence of the lighting defect again at least on the portion of the display panel having the lighting defect after the cleaning. The inspection apparatus determines that the display panel has no defect if detecting no lighting defect after the cleaning or if determining that pre-cleaning lighting defect information and post-cleaning lighting defect information does not match, and the inspection apparatus determines that the display panel has a defect if determining that the pre-cleaning lighting defect information and the post-cleaning lighting defect information match.
According to the system of inspecting a display panel (which will hereinafter be simply referred to as “inspection system”) configured in the above manner, only when a lighting defect on the display panel is detected at the first inspection, cleaning and a re-inspection are carried out. This allows conducting an efficient inspection of the display panel. The above “lighting defect information” is a statement including description of the position, shape, size, and the like of a lighting defect. If a lighting defect is caused by dust or dirt, cleaning the dust or dirt ought to cause the lighting defect to disappear or reduce in size or displace. Taking that assumption into consideration, the inspection system of the above configuration determines whether a lighting defect is caused by a defect of the display panel, based on whether pre-cleaning lighting defect information and post-cleaning lighting defect information match. This allows an inspection of the display panel to be conducted accurately, compared to a case where an operator determines whether a lighting defect is caused by a defect of the display panel by making a visual check. The inspection system automatically determines whether the pre-cleaning lighting defect information and the post-cleaning lighting defect information match. This allows an inspection of the display panel to be conducted more efficiently, compared to a case where an operator determines whether a lighting defect is caused by a defect of the display panel by making a visual check.
An inspection of the display panel, the inspection being configured in the above manner, may be conducted at any stage of a process of producing a display device and may be conducted several times. For example, the inspection may be conducted as an inspection of the display panel in various states, such as a state in which the display panel has been assembled into the display device, a state in which a backlight is not attached to the display panel (liquid crystal panel) yet, and a state in which the backlight and polarizers are not attached to the display panel (liquid crystal panel) yet.
The inspection system may be configured such that the display-device-in-process to be inspected is moved between the inspection apparatus and the cleaner or such that the display-device-in-process to be inspected is not moved and at least one of the inspection apparatus and the cleaner is moved instead. The latter configuration is a configuration in which, for example, a conventional inspection apparatus is provided with the cleaner and a shifter that shifts the cleaner.
A method of inspecting a display panel according to the technology described herein includes a lighting defect detecting process of obtaining an image of the display panel relating a lighting condition thereof and processing the image and determining presence or absence of the lighting defect, and obtaining lighting defect information relating the lighting defect, a cleaning process of cleaning at least a portion of the display panel having the lighting defect according to determination that the display panel has a lighting defect, and a defect detecting process of determining presence or absence of the lighting defect again at least on the portion of the display panel having the lighting defect. In the defect detecting process, it is determined that the display panel has no defect if detecting no lighting defect after the cleaning or if determining that pre-cleaning lighting defect information and post-cleaning lighting defect information does not match, and it is determined that the display panel has a defect if determining that the pre-cleaning lighting defect information and the post-cleaning lighting defect information match.
According to this method of inspecting a display panel, in the same manner as in the above-described system of inspecting a display panel, only when a lighting defect in the display panel is detected at the first inspection, cleaning and a re-inspection are carried out. This allows conducting an efficient inspection of the display panel. Whether a lighting defect is caused by a flaw of the display panel is determined based on whether pre-cleaning lighting defect information and post-cleaning lighting defect information match. This allows an inspection of the display panel to be conducted accurately, compared to a case where a worker determines whether a lighting defect is caused by a flaw of the display panel by making a visual check. Whether the pre-cleaning lighting defect information and the post-cleaning lighting defect information match is automatically determined. This allows an inspection of the display panel to be conducted more efficiently, compared to a case where a worker determines whether a lighting defect is caused by a flaw of the display panel by making a visual check.
The system and method for inspecting a display device according to the technology described herein can inspect a display panel accurately and efficiently.
Some embodiments of the technology described herein will hereinafter be described in detail with reference to drawings, as modes for carrying out the technology. The technology described herein will not be limited to the embodiments described below, and may be modified or improved in various manners, based on knowledge of those who skilled in art, to be carried out in various modes.
<Configuration of System of Inspecting Display Panel>
A system 10 for inspecting a display panel (which will hereinafter be referred to simply as “inspection system 10” in some cases) according to a first embodiment is shown in
The camera 18 is configured to take an overall image of an object to be inspected placed on the mounting table 16 or take a magnified image of a part of the object. The cleaner 20 includes a cleaning head 20a and a cleaning jig 20b attached to the cleaning head 20a. In
<Configuration of Object to be Inspected (Liquid Crystal Module)>
The liquid crystal module M to be inspected by the inspection system 10 will then be described. As shown in
The liquid crystal panel 30 has a pair of transparent (highly translucent) substrates 30a and 30b, and a liquid crystal layer 30c interposed between the substrates 30a and 30b, the liquid crystal layer 30c containing liquid crystal molecules that change in optical properties when exposed to an electric field applied thereto. The substrates 30a and 30b kept separated apart across a cell gap as thick as the liquid crystal layer 30c are pasted together with a sealant (not depicted). The substrates 30a and 30b are each fabricated by stacking films on a substantially transparent glass substrate by a known method, such as photolithography. Of the substrates 30a and 30b, the substrate on the front side (front surface side) serves as a CF substrate (counter substrate) 30a, and the substrate on the back side (back surface side) serves as an array substrate (thin-film transistor substrate or active matrix substrate) 30b. On the inner surface side of the substrate 30a and on the same of the substrate 30b, an oriented film 30d and an oriented film 30e for orienting liquid crystal molecules included in the liquid crystal layer 30c are formed, respectively.
Of the pair of substrates 30a and 30b, the array substrate 30b disposed on the back side carries numbers of switching elements (e.g., thin-film transistors or TFTs) 40 connected to source lines and gate lines perpendicular to each other, and number of pixel electrodes 42 connected to the switching elements 40, the switching elements 40 and the pixel electrodes 42 being arranged in a matrix formation. These switching elements 40 and pixel electrodes 42 are overlaid with the above-described oriented film 30e. The CF substrate (counter substrate) 30a disposed on the front side carries a color filter 44 composed of colored portions R (red), G (green), and B (blue) arranged in given patterns, and black matrixes (shading films) 46 partitioning colored portions adjacent to each other. These color filter 44 and black matrixes 46 are overlaid with an overcoat film 48, which is overlaid with a counter electrode 50 made of a transparent electrode material, such as indium tin oxide (ITO). The counter electrode 50 is then overlaid with the above-described oriented film 30d.
As shown in
<Method of Inspecting Display Panel>
The inspection system 10 is used in a process of producing the liquid crystal module M configured in the above manner. An inspecting method carried out by the inspection system 10 will hereinafter be described in detail with reference to a flowchart of a liquid crystal inspection program shown in
(I) Lighting Defect Detecting Process
(II) Cleaning Process
When determining that the liquid crystal panel 30 has a lighting defect, the controller 24, at S6, causes the cleaner shifter 22 to shift the cleaner 20 to a spot where the lighting defect is detected. Subsequently, the jig lift of the cleaning head 20a moves down the cleaning stick 20b to bring it into contact with the liquid crystal panel 30. The cleaner shifter 22 then causes the cleaning stick 20b to operate to clean the liquid crystal panel 30. If several spots of lighting defects are present, the cleaning stick 20b is moved up after finishing with cleaning one spot and then the cleaner 20 is shifted to the next spot of a lighting defect to carry out cleaning in the same manner. If all the spots of lighting defects are cleaned, the cleaner 20 is shifted back to a stand-by position outside the liquid crystal module M.
(III) Defect Detecting Process
After completion of cleaning of the liquid crystal panel 30, whether the liquid crystal panel 30 has a lighting defect is determined again at S7 to S9. If the liquid crystal panel 30 has several spots of lighting defects, the camera 18 takes an overall image of the liquid crystal panel 30, and the controller 24 determines whether the liquid crystal panel 30 has a lighting defect based on image data of the overall image. If it is determined that the above lighting defect disappears, the liquid crystal module M is determined to be normal at S4, and the inspection is ended.
If a lighting defect is still present, the controller 24, at S10, obtains post-cleaning lighting defect information. At S11 following S10, the controller 24 compares pre-cleaning lighting defect information with post-cleaning lighting defect information to determine whether a lighting defect of which pre-cleaning lighting defect information and post-cleaning lighting defect information match completely in the location, shape, and size of the lighting defect is present. If a lighting defect is caused by dust or dirt, cleaning the dust or dirt ought to cause the lighting defect to change in shape or reduce in size or displace. When a lighting defect of which pre-cleaning lighting defect information and post-cleaning lighting defect information match completely is not present, therefore, it is determined at S4 that the liquid crystal module M is normal. When a lighting defect of which pre-cleaning lighting defect information and post-cleaning lighting defect information match completely is present, on the other hand, it is determined at S12 that the liquid crystal panel 30 of the liquid crystal module M has a defect. An inspection of one liquid crystal module M is then ended.
As described above, according to the inspection system 10, whether a lighting defect is caused by a defect of the liquid crystal panel 30 is determined, based on whether pre-cleaning lighting defect information and post-cleaning lighting defect information match. This allows an inspection of the liquid crystal panel 30 to be conducted more accurately, compared to a case where an operator determines whether a lighting defect is caused by foreign matter or a defect by making visual check. The controller 24 automatically determines whether the pre-cleaning lighting defect information and the post-cleaning lighting defect information match. This allows an inspection of the liquid crystal panel 30 to be conducted more efficiently, compared to a case where an operator determines whether a lighting defect is caused by a defect of the liquid crystal panel 30 by making visual check.
The cleaning process by the inspection system 10 may be carried out as a simple process for detecting a defect of the liquid crystal panel 30. Such a simple cleaning process will reduce a time required for cleaning and therefore reduce an inspection time. According to the inspection system 10, because the cleaner 20 is configured to clean a part of the liquid crystal panel 30, a time required for cleaning can be reduced, compared to a case where the liquid crystal panel 30 is cleaned as a whole.
In the lighting defect detecting process, when a magnified image of a spot of a lighting defect is taken to obtain lighting defect information, a magnified image of the spot is taken again after cleaning to obtain another piece of lighting defect information. Pre-cleaning lighting defect information and post-cleaning lighting defect information obtained from these magnified images are then compared with each other. Specifically, in the lighting defect detecting process, when a spot of the lighting defect of which a magnified image has been taken is the only one spot of a lighting defect that has been detected, a determination on the presence/absence of a lighting defect is made only on that spot in the defect detecting process. In such a case, whether a lighting defect is caused by a defect of the liquid crystal panel 30 is determined based on lighting defect information obtained by processing a magnified image of a lighting defect. This allows conducting a more accurate inspection of the liquid crystal panel 30.
<Modifications>
The inspection system 10 according to the first embodiment is used to conduct an inspection of the liquid crystal panel 30 of the liquid crystal module M that has been produced. However, the inspection system 10 may also be used to conduct an inspection of the liquid crystal panel 30 of the liquid crystal module M that is still in a stage of production.
An inspection system 60 for inspecting the liquid crystal panel shown in
The inspection system 60 executes the same inspecting method as executed by the above inspection system 10 except that, in the cleaning process, both the upper surface side and lower surface side of a spot where a lighting defect is detected are cleaned.
An inspection system 70 for inspecting a liquid crystal panel 30 shown in
An inspection system 80 for inspecting a liquid crystal panel shown in
An inspection system 90 for inspecting a liquid crystal panel according to a second embodiment is shown in
The rotary base 96 includes a disc-shaped table 96a serving as a placing unit. Liquid crystal modules M (four modules M in
As described above, the inspection system 90 for inspecting a liquid crystal panel according to the second embodiment is configured to simultaneously execute the lighting defect detecting process, the cleaning process, and the defect detecting process, and therefore can conduct an efficient inspection of the liquid crystal panel 30.
A single inspection apparatus may be adopted. An inspection system 100 for inspecting a liquid crystal panel shown in
| Number | Date | Country | Kind |
|---|---|---|---|
| 2018-042741 | Mar 2018 | JP | national |
