JP5019605B2 - Bright spot correction method for liquid crystal display device - Google Patents

Description

  The present invention relates to a bright spot correction method in which a bright spot is corrected using a laser for a bright spot defective pixel discovered in an inspection process of a liquid crystal display device.

  As current liquid crystal display devices, active matrix liquid crystal display devices have become mainstream because there is no crosstalk between adjacent pixels and a good display image can be realized. This active matrix type liquid crystal display device is generally a transparent substrate connected to a plurality of thin film transistors (TFTs) arranged in a matrix in the vicinity of intersections of orthogonal signal lines and scanning lines on an insulating substrate made of a glass material. It includes an array substrate having a pixel electrode and an alignment film formed on the electrode.

  In addition, an insulating substrate made of the same glass material disposed opposite to the array substrate is provided with a counter substrate in which a transparent counter electrode and an alignment film are sequentially laminated. Further, in the case of color display, three primary color RGB color filters are provided on either the array substrate or the counter substrate. A liquid crystal panel made up of a liquid crystal member is sealed between the array substrate and the counter substrate to constitute a liquid crystal panel. A liquid crystal display device is configured by attaching a polarizing plate to the outer surface side of the array substrate and the counter substrate.

  By the way, when a luminescent spot defect is confirmed by the luminescent spot inspection of the liquid crystal panel, a method of turning the luminescent spot into a dark spot or destroying a foreign substance using a YAG laser device, or a laser beam at a corresponding portion of the corresponding color filter. Is used to blacken the portion and block the light regardless of the presence or absence of the drive voltage of the pixel electrode (see, for example, Patent Document 1).

In this case, in the method of correcting a defective pixel by the presence of a foreign substance that electrically connects the pixel electrode and the counter electrode, the foreign substance is directly irradiated with laser from the outside of the liquid crystal panel to destroy the foreign substance. Thus, the defective pixel is corrected by releasing the conductive state between the two electrodes.
JP 2003-29226 A

  However, if the focus is focused directly on the foreign material itself and it is destroyed by irradiating a laser, the damage to the peripheral wiring pattern and film layer is greatly caused by the scattering of the foreign material due to this destruction, the residual material, or the thermal effect of the destruction. In some cases, problems such as light leakage due to perforation of the film layer and liquid crystal alignment failure due to alignment film damage may occur. In particular, when the foreign material is a metal-based material, destruction is often difficult even when laser irradiation is performed, and a relief method for that purpose has been desired.

  The present invention has been made in response to the above-described problems, and is a method for correcting a bright spot of a liquid crystal display device capable of reliably correcting a defective pixel even if a pixel defect occurs due to a metallic foreign matter. To provide.

In the present invention, a pixel electrode and an alignment film are stacked on one insulating substrate, a counter electrode and an alignment film are stacked on the other insulating substrate, and both substrates are opposed to each other through a liquid crystal layer. In the liquid crystal display brightening correction method for correcting defective pixels in which a pixel electrode and a counter substrate in a liquid crystal panel formed to face each other are electrically connected by a conductive foreign substance using a laser, the wavelength of the liquid crystal panel is Irradiate a laser set to 500 nm or more and 1100 nm or less, and set the distance between the processing point of the foreign matter and the focal point to 5 μm or more and 20 μm or less to make the laser defocused in front of the foreign matter. by the continuously shot as another part by very small area overlap across an alignment film on an insulating substrate located in the irradiation side of the laser The alignment film and the electrode portion of the shot portion are cut while the foreign matter remains .

  In addition, the laser shot is performed after the laser beam is irradiated to the foreign object to generate bubbles around the foreign object prior to the laser shot.

  According to the present invention, the display quality can be improved by irradiating the defocused laser across the peripheral portion of the foreign matter without irradiating the entire foreign matter with the laser, thereby suppressing the influence on the peripheral portion of the foreign matter as much as possible. It is possible to correct a defective pixel while holding it.

  Hereinafter, a first embodiment of the present invention will be described in detail with reference to FIGS.

  1 and 2 are schematic diagrams for explaining the outline of the bright spot correcting method of the liquid crystal display device of the present invention, and FIGS. 3 and 4 show the presence of foreign matter.

  First, a liquid crystal display device, which is an object to be corrected, will be described. On one surface of a transparent insulating substrate 11 made of a glass material, signal lines 12 and scanning lines 13 are insulated from each other so as to be substantially orthogonal to each other. Near the intersection, thin film transistors (TFTs) 14 having a gate electrode connected to the scanning line 13 and a signal line 12 connected to the drain electrode are arranged in a matrix. On the insulating substrate 11 including the TFT 14, a color filter 15 made of a colored layer made of an acrylic material and colored in red, blue, and green is formed. On the color filter 15, indium tin oxide (ITO) or the like is formed. A transparent pixel electrode 16 is provided. The pixel electrode 16 is connected to the source electrode of the TFT 14 through a through hole formed in the colored layer of the color filter 15, and an alignment film 17 made of polyimide or the like is further provided on the upper surface of the pixel electrode 16 or the like. Thus, the array substrate 18 is configured.

  Further, the counter substrate 19 facing the array substrate 18 has a transparent insulating substrate 20 which is similarly made of a glass material. A transparent counter electrode 21 made of ITO or the like and an alignment film 22 made of polyimide or the like provided on the upper surface of the counter electrode 21 are provided on one plane of the transparent insulating substrate 20 facing the array substrate 18. ing.

  The array substrate 18 and the counter substrate 19 are arranged to face each other with a predetermined gap so that the alignment films 17 and 22 face each other, and are bonded together via a seal material 23. A liquid crystal layer 24 made of a liquid crystal member is sealed in the gap, and the thickness of the liquid crystal layer 24 is defined by a spacer 25 interposed between the array substrate 18 and the counter substrate 19 to form a liquid crystal panel 26. The Polarizers 27 and 28 are attached to the outer surface side of the liquid crystal panel 26 to form a liquid crystal display device 29.

  The liquid crystal panel 26 or the liquid crystal display device 29 thus configured is inspected in the image quality inspection process, and if a bright spot defect is found, the bright spot defect is corrected.

  As shown in FIG. 1, in this correction device, an illuminating device 33 that supplies white light of uniform intensity through the transmission hole 31 is disposed below an XY table 32 having a hollow transmission hole 31 in the center. . A liquid crystal display device 29 is placed on the XY table 32. The XY table 32 is provided with a moving device 34 for processing positioning. The moving device 34 is for controlling the position of the liquid crystal display device 29 placed on the XY table 32, and can move the XY table 32 in the XY directions. The liquid crystal display device 29 is connected to a liquid crystal driving circuit 35 for inspection and correction.

A laser optical system 41 such as an image forming optical system or a condensing optical system is disposed above the liquid crystal display device 29 of the XY table 32. Here, a case where an imaging optical system is used as the laser optical system 41 will be described as an example. On the optical axis of the condenser lens 42 of the laser optical system 41, a laser oscillator 46 that generates YGA laser light through a slit 45 having a beam splitter 43 and a predetermined opening 44 is provided. The laser oscillator 46 is set to generate a laser having a rated output of about 5 to 10 mW having a wavelength of 500 nm or more and a pulse width of 1 × 10 ⁻⁶ sec or less. This laser beam is shaped into a beam of a predetermined size by the slit 45 and is formed (focused) at a predetermined focal length by the condenser lens 42. The size of the opening 44 of the slit 45 is set so that the size at the processing point with the laser light is 5 μm □ or less. A CCD camera 48 is disposed in the reflection direction of the beam splitter 43 so as to face the beam splitter 43 via an imaging lens 47, and a monitor 49 is connected to the camera 48.

  A method of correcting a defective pixel of the liquid crystal display device using the correction device for the liquid crystal display device configured as described above will be described.

  First, the liquid crystal display device 29 is placed on the XY table 32, and the liquid crystal driving circuit 35 and the illumination device 33 are turned on, so that white light from the illumination device 33 passes through the transmission holes 31 of the XY table 32. And projected onto one surface of the liquid crystal display device 29. At the same time, incident light is condensed by the condenser lens 42 from an incident illumination source (not shown) provided in the laser optical system 41 and is irradiated on the other surface of the liquid crystal display device 29.

  The reflected light of the incident light from the liquid crystal display device 29 is imaged on the imaging surface of the camera 48 via the condenser lens 42, the beam splitter 43, and the imaging lens 47. The imaging output of the camera 48 is supplied to a monitor 49, and a reproduced image can be displayed on the screen of the monitor 49. Accordingly, since the liquid crystal display device 29 is moved by moving the XY table 32 in the two-dimensional direction of XY by the moving device 34, the reproduced image on the monitor 49 can be changed accordingly, and the liquid crystal display device 29 can be changed accordingly. The entire screen corresponding to the display surface can be scanned.

  When the occurrence of a bright spot defective pixel is confirmed, the projected monitor image is monitored, the movement device 34 is controlled to move the XY table 32, and the laser irradiation position of the laser optical system 41 is set to the bright spot defective pixel. Align to.

  As the defective pixel, for example, as shown in FIG. 3, a conductive foreign material 51 that breaks through the alignment films 17 and 22 is interposed between the pixel electrode 16 and the counter electrode 21. Assume a conduction defect that is short-circuited by the foreign object 51 and has the same potential.

  After aligning the laser optical system 41 with the defective pixel, a laser is output from the laser oscillator 46. This laser is incident on the slit 45 and is adjusted in size, and then condensed by the condenser lens 42. At this time, as shown in FIG. 2, the light is focused (focused) so as to give the laser focus F in front of the liquid crystal display device 29. Therefore, the foreign matter 51 in the liquid crystal layer 24 of the liquid crystal display device 29 is irradiated with a laser that reaches the foreign matter 51 in a non-focus range after the focus F is once focused before reaching the foreign matter 51, that is, in a defocused state. It will be.

  This defocusing is set by moving the laser optical system 41 once again by moving the laser optical system 41 in the vertical direction perpendicular to the XY table 32 by the moving device 34 to align the laser focus F with the foreign object 51. This can be achieved by moving the device 34 in the + Y direction, which is the direction away from the foreign object 51, and relatively separating the two. When this defocusing is set, the output of the laser oscillator 46 may be switched so as to be lower than the rated output.

  The distance a between the processing point of the foreign object 51 and the focal point F in this defocusing is preferably set to a distance of 5 to 20 μm. When the distance a is 5 μm or less, the laser energy is too strong and the foreign matter 51 itself may be destroyed. When the distance a is 20 μm or more, the energy is too weak, and there is a possibility that the correction described later cannot be performed.

  In addition, this shot is shot along the contour of the foreign matter 51, not the entire shot of the foreign matter 51 corresponding to the bright spot defect pixel. That is, as shown in FIG. 4, the defocused size defined by the slit 45 along the periphery of the foreign object 51 is not destroyed by focusing on the whole or the center of the foreign object 51. In addition, the XY table 32 and the laser optical system 41 are moved by the moving device 34 so that it is possible to continuously perform shots so that a part of each of the small areas shown in a rectangular shape (rectangular shape) indicated by a broken line in FIG. Control the relative position of. This movement can be dealt with by moving the laser optical system 41 by moving the XY table 32 side, or by moving the laser optical system 41 in the XY direction by the moving device 34. It is also possible to move the laser beam simultaneously, and the laser beam can be scanned by monitoring the position of the white light on the monitor image.

  By such a laser shot, the counter electrode 21 and the alignment film 22 corresponding to the peripheral portion of the foreign material 51 are peeled off by the defocused laser, so that the foreign material 51 itself faces the pixel electrode 16 in the liquid crystal layer 24. Even if it remains between the electrodes 21, at least the counter electrode 21 located on the side of the counter substrate 19 on the side irradiated with the laser is separated from other circuit systems by continuous superimposed shots by the laser slit 45. The pixel portion is darkened. In this process, since the entire foreign matter 51 is not directly destroyed by the laser, it is possible to prevent the foreign matter 51 from being damaged or scattered, or from being damaged by a thermal effect at the time of destruction.

  In this way, the counter electrode 21 at the periphery of the foreign object 51 of the bright spot defective pixel due to the presence of the foreign object 51 that short-circuits the electrodes 16 and 21 between the array substrate 18 and the counter substrate 19 is damaged, and the foreign object 51 exists. The bright spot defect of the liquid crystal display device can be corrected by separating at least one of the two electrodes 16 and 21 from other circuits.

  In the above description, the case where the polarizing plates 27 and 28 are bonded to both sides of the liquid crystal panel 26 is described as an example, but the correction is made at the stage of the liquid crystal panel 26 where the polarizing plates 27 and 28 are not bonded. Of course, it is also possible to apply. The case where the correction is performed by the liquid crystal panel 26 is also included in the expression of the bright spot correction method of the liquid crystal display device in the present invention.

  In addition, a case where slit processing by an imaging optical system is used as the laser optical system 41 is described. In addition to this, a condensing optical system in which a beam diameter becomes a spot-shaped laser without using a slit is used. Processing with the laser optical system 41 is also possible. In this processing, since no slit is used, the beam shape at the processing point is a spot shape such as a round shape unlike a rectangular shape, but is exactly the same as in the case of the imaging optical system except for this shape change. The machining operation can be performed.

  In this way, the shot is performed so that the laser is continuously superimposed along the peripheral portion of the foreign material 51. Prototyping / examination of the relationship between the shot and the processing range (distance) from the peripheral portion of the foreign material 51 is performed. Went.

As a sample for this measurement, a 13.3 inch WXGA type liquid crystal panel was used. By intentionally disturbing the orientation of this panel, a small black spot having a diameter φ = 10 μm was intentionally created by a repair device. The brightness of the illumination device (backlight) was set to 3500 cd / m ^2, and light leakage was determined visually and with a ND5% filter at a distance of 30 cm from the substrate surface. The measurement results are shown in Table 1.

  From the results of Table 1, it has been found that the processing range from the periphery of the foreign material to the peripheral portion thereof is preferably set to 2.0 μm or less where light leakage is not visually recognized. However, since the processing range may vary depending on the brightness of the backlight or the ability of the inspector, the processing range is preferably determined according to individual product standards.

  Next, a second embodiment will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected about what was demonstrated in 1st Embodiment, and the detailed description is abbreviate | omitted.

  In this embodiment, a laser having a wavelength of 1100 nm or less and a pulse width of 50 ns or less is used as the laser output from the laser optical system 41. Prior to using this laser to make a shot along the peripheral edge of the foreign object 51, the center part of the foreign object 51 is first irradiated with a laser having a small energy of 0.5 mW or less, which is less than the rated output. As shown in FIG. 5, bubbles 61 are generated in the liquid crystal layer 24 around the foreign matter 51 so as to surround the foreign matter 51. When the bubble 61 is generated, the laser output is increased or switched to a specified rated output, and in the period until the bubble 61 disappears, the peripheral edge of the foreign object 51 is the same as described in the first embodiment. Laser shot is performed along the part. For this purpose, a laser having an oscillation frequency of 1 kHz or less is used, and if the relative moving speed of the XY table 32 and the laser optical system 41 is set to 1000 μm / sec, it becomes possible to perform work while the bubbles 61 remain. Therefore, it is suitable.

  By adopting such a bright spot correction method, bubbles 61 are first generated around the target foreign matter 51 before laser processing is performed, and the original laser processing is performed during the period in which the bubbles 61 remain. As a result, the electrode foil or alignment film residue 62 generated by the separation by processing does not float in the liquid crystal layer 24 but remains in the range where the bubbles 61 exist as shown in FIG. The air bubbles 61 are not scattered outside. Therefore, the processing residue 62 generated by the processing is left as it is on the lower side of the liquid crystal layer 24, in other words, on the surface of the alignment film 17 on the array substrate 18 side, as indicated by an arrow in FIG. 62 is adhered and deposited. Light leakage can be reduced by blackening due to the orientation change of the alignment film 17 to which the residue 62 is adhered. Therefore, the influence of the light leakage from the place removed by the laser processing is further suppressed by intentionally disturbing the orientation by attaching the residue 62 on the electrode 16 and the alignment film 17. It becomes possible.

  In the above description, the bright spot correction method by slit processing equipped with an imaging optical system has been described. However, it is possible to suppress the thermal influence (damage) at the processing point due to the pixel size or the size of foreign matter. If so, it is also possible to use a laser device equipped with a condensing optical system.

In the above description, the case where the color filter is provided on the array substrate side is described. However, the present invention can also be applied to the case where the color filter is provided on the counter substrate side. Needless to say, the present invention can be similarly applied if the liquid crystal panel is held on the XY table so that the laser is irradiated from the substrate side.

1 is a schematic configuration diagram for explaining a bright spot correcting method according to a first embodiment of a liquid crystal display device according to the present invention. Explanatory drawing for demonstrating a defocus state similarly. Sectional drawing of the liquid crystal panel for demonstrating the state of a foreign material similarly. Explanatory drawing for carrying out the laser shot of the periphery of a foreign material similarly. Sectional drawing of the liquid crystal panel for demonstrating the state around the foreign material for demonstrating the bright spot correction method which concerns on 2nd Embodiment of the liquid crystal display device which concerns on this invention. Sectional drawing of the liquid crystal panel for demonstrating the state of the foreign material periphery after a laser shot similarly.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11, 20 ... Insulating substrate 16 ... Pixel electrode 17, 22 ... Alignment film 18 ... Array substrate 19 ... Counter substrate 21 ... Counter electrode 24 ... Liquid crystal layer 26 ... Liquid crystal panel 41 ... Laser optical system 42 ... Condensing lens 45 ... Slit 46 ... Laser oscillator

Claims (3)

A pixel electrode and an alignment film are stacked on one insulating substrate, and a counter electrode and an alignment film are stacked on the other insulating substrate, and these substrates are arranged so that the alignment film faces the liquid crystal layer. in the pixel electrode and the bright point correction method for a liquid crystal display device for correcting using laser defective pixels between the opposing substrates is conducted by the conductive foreign matter in the liquid crystal panel which is formed by opposing,
The liquid crystal panel is irradiated with a laser whose wavelength is set to 500 nm or more and 1100 nm or less, and this laser is set to a distance between the processing point of the foreign matter and the focal point to 5 μm or more and 20 μm or less and has a focal point in front of the foreign matter. by continuously shot as mutually partially overlap each small area across the alignment film on the insulating substrate in the defocused state is positioned on the irradiation side of the laser and the periphery of the foreign substance, the foreign substance A method of correcting a bright spot of a liquid crystal display device, wherein the alignment film and the electrode portion of the shot portion are cut while remaining in the film .   2. The liquid crystal according to claim 1, wherein prior to the shot, the foreign matter is irradiated with a laser with an output weaker than an output at the time of the shot to generate bubbles around the foreign matter, and then the shot is performed. A bright spot correction method for a display device.   3. The method for correcting a bright spot of a liquid crystal display device according to claim 1, wherein the liquid crystal panel has a color filter on one of the substrates and irradiates the laser from the other substrate side.

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