JP3793866B2 - Method for correcting defective pixels in liquid crystal display panel - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a defective pixel correction method for a liquid crystal display panel.
[0002]
[Prior art]
For example, in an active matrix liquid crystal display panel including a thin film transistor as a switching element, when a driving voltage is not applied to the corresponding pixel electrode due to a manufacturing defect of the thin film transistor, the normally white method The corresponding pixel always becomes a bright spot, and the image quality deteriorates. Therefore, conventionally, such defective pixels are corrected.
[0003]
Next, an example of a conventional defective pixel correction method will be described. First, the structure of the liquid crystal display panel will be briefly described with reference to FIG. This liquid crystal display panel includes a pair of glass substrates 1 and 2. A pixel electrode 3 made of ITO and a thin film transistor 4 are provided in a matrix on the lower surface of one glass substrate 1, and an alignment film 5 is provided on the lower surface thereof. On the upper surface of the other glass substrate 2, a black mask 6, a color filter 7, a common electrode 8 made of ITO and an alignment film 9 are provided. The glass substrates 1 and 2 are bonded to each other via a sealing material (not shown), and a liquid crystal 10 is sealed between them.
[0004]
If the thin film transistor 4 provided with the liquid crystal display panel has a manufacturing defect, as shown by an arrow in FIG. 8B, the first laser beam is applied to the substantially central portion of the pixel electrode 3 corresponding thereto. Irradiate to generate bubbles 11 in the liquid crystal 10 at the pixel electrode 3, and then irradiate the pixel electrode 3 with a second laser beam at one or a plurality of locations. And the alignment film 5 underneath is physically destroyed. The destructive material generated thereby is retained in the bubbles 11. After this, the bubbles 11 disappear. Then, the liquid crystal 10 in the destruction area is always aligned in the vertical direction or the horizontal direction, and the pixels in the destruction area are always displayed in black. Thus, the defective pixel is corrected.
[0005]
[Problems to be solved by the invention]
By the way, in such a conventional defective pixel correction method, even if the second laser beam is irradiated, black display may not be achieved depending on the degree of the defect, and it may be visually recognized as a bright spot. For this reason, studies have been made to improve the correction accuracy by continuously irradiating the second laser beam with a reduced beam diameter. In this method, for example, as indicated by an arrow in FIG. 9, a defective pixel 12 (a pixel here is a pixel constituted by a portion of one pixel electrode 3 that is not covered by the black mask 6. First, the irradiation is continuously performed in the left direction from the irradiation start point indicated by the white circle in the lower right corner of the defective pixel 12, and then continuously from the left to the right at a position shifted by a predetermined pitch upward. Next, irradiation is continuously performed from the right side to the left side at a position shifted by a predetermined pitch on the upper side. Thereafter, such irradiation is repeated, and irradiation is performed at an irradiation end point indicated by a black circle in the upper right corner of the defective pixel 12. Has ended. In this defective pixel correction method, since the entire defective pixel 12 is irradiated almost uniformly, it seems that the defective pixel 12 is sufficiently corrected, but it is still not sufficient, and it has been found that light leakage slightly occurs. This is considered to be due to the fact that the irradiation line is discontinuous, and in particular, the peripheral portion of the defective pixel 12 is not sufficiently irradiated from the experimental results described later.
An object of the present invention is to correct a defective pixel so that light leakage can be further reduced.
[0006]
[Means for Solving the Problems]
According to the present invention, a liquid crystal display panel in which liquid crystal is sealed between a pair of substrates is irradiated with a laser beam to physically destroy the defective pixel portion, thereby correcting the defective pixel. In the method for correcting defective pixels of a display panel, the irradiation pattern of the laser beam scans at least substantially the whole of the defective pixels, and the entire length is continuously formed in a line along the peripheral portion of each side. to those who to include the first irradiation pattern for irradiating a second irradiation pattern for scanning the inside. According to the present invention, since the irradiating continuously the entire length in a line form along the periphery of each side of at least the defective pixel with a laser beam, the defective pixel becomes always black display, light leakage It can be further reduced.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
1 to 6 show the second laser beam irradiation patterns in the first to sixth examples of the defective pixel correcting method of the liquid crystal display panel according to the present invention, respectively. In any example, the beam size of the first laser beam for generating bubbles in the liquid crystal at the defective pixel 12 is 10 to 30 μm (preferably 20 μm), and the energy density is 10 to 30 J /. cm ² (preferably 20 J / cm ² ) , and the beam size of the second laser beam for physically destroying the pixel electrode and the alignment film in the defective pixel 12 is 1 to 4 μmφ (preferably 2 to 3 μmφ). ) And the energy density is 70 to 100 J / cm ² . The second laser beam is a rectangular wave of 20 Hz, and the scanning speed during irradiation is such that the previous irradiation area and the next irradiation area slightly overlap, in other words, the irradiation area is exactly the same. The speed was continuous.
[0008]
In the second laser beam irradiation pattern in the first example shown in FIG. 1, first, from the irradiation start point indicated by the white circle at the lower right corner of the defective pixel 12, clockwise along the periphery of the defective pixel 12. Irradiated almost continuously for one round. In this case, the irradiation line a was set at a position t = 7.5 μm away from the edge portion of the defective pixel 12. Next, irradiation is continuously performed in the left direction from the lower right corner of the defective pixel 12, and then irradiation is performed continuously in the right direction from the left side at a position shifted by a predetermined pitch on the upper side, and then at a position shifted by a predetermined pitch on the upper side. Irradiation was continuously performed from the right side to the left direction, and such irradiation was repeated, and the irradiation was terminated at the irradiation end point indicated by a black circle in the upper right corner of the defective pixel 12. In this case, the pitch P was 20 μm.
[0009]
Next, the irradiation pattern of the second laser beam in the second example shown in FIG. 2 is opposite to that shown in FIG. That is, first, irradiation is continuously performed in the left direction from the irradiation start point indicated by a white circle in the upper right corner of the defective pixel 12, and then irradiation is continuously performed in the right direction from the left side at a position shifted by a predetermined pitch downward. Next, irradiation was continuously performed from the right side to the left direction at a position shifted by a predetermined pitch downward, and such irradiation was repeated until the lower right corner of the defective pixel 12 was irradiated. In this case, the pitch P was 20 μm. Next, irradiation was performed almost continuously in the counterclockwise direction along the periphery of the defective pixel 12 from the lower right corner of the defective pixel 12, and the irradiation was terminated at the irradiation end point indicated by the black circle in the lower right corner of the defective pixel 12. . In this case, the irradiation line a was set at a position t = 7.5 μm away from the edge portion of the defective pixel 12.
[0010]
Next, in the irradiation pattern of the second laser beam in the third example shown in FIG. 3, first, the same irradiation as in the case shown in FIG. 2 was performed. Next, irradiation is continuously performed upward from the lower right corner of the defective pixel 12, and then irradiation is continuously performed downward from the upper side at a position shifted by a predetermined pitch on the left side, and then at a position shifted by a predetermined pitch on the left side. Irradiation was continuously performed from the lower side to the upper direction, and such irradiation was repeated, and irradiation was terminated at the irradiation end point indicated by a black circle in the upper left corner of the defective pixel 12. The pitch P in this case was also 20 μm.
[0011]
Next, in the second laser beam irradiation pattern in the fourth example shown in FIG. 4, a black circle slightly below the center of the defective pixel 12 from the irradiation start point indicated by a white circle in the lower right corner of the defective pixel 12. Until the irradiation end point indicated by the mark, substantially the entire circumference along the periphery of the defective pixel 12 and the inner region were continuously irradiated in the form of an angular spiral in the clockwise direction. In this case, the irradiation line a along the peripheral portion of the defective pixel 12 was set at a position t = 7.5 μm away from the edge portion of the defective pixel 12. The pitch P inside the irradiation line a was 14 μm.
[0012]
Next, in the second laser beam irradiation pattern in the fifth example shown in FIG. 5, from the irradiation start point indicated by the white circle on the lower right side slightly from the center of the defective pixel 12, from the center of the defective pixel 12. The irradiation was performed evenly so that the entire circumference along the periphery of the defective pixel 12 and the area inside it were in a so-called one-stroke pattern and did not intersect anywhere until the irradiation end point indicated by the black circle on the lower left side. In this case, the irradiation line a along the peripheral portion of the defective pixel 12 was set at a position t = 7.5 μm away from the edge portion of the defective pixel 12. The pitch P inside the irradiation line a was 20 μm.
[0013]
Next, in the second laser beam irradiation pattern in the sixth example shown in FIG. 6, the black circle at the center of the defective pixel 12 from the irradiation start point indicated by a white circle slightly below the center of the defective pixel 12. Until the irradiation end point indicated by the mark, the entire periphery along the periphery of the defective pixel 12 and the region inside it were irradiated in a so-called one-stroke pattern, intersecting or overlapping, and evenly irradiated. In this case, the irradiation line a along the peripheral portion of the defective pixel 12 was set at a position t = 10 μm away from the edge portion of the defective pixel 12. The pitch P inside the irradiation line a was 20 μm.
[0014]
In the case of the conventional second laser beam irradiation pattern shown in FIG. 9, the irradiation line in the peripheral portion of the defective pixel 12 in the second laser beam irradiation pattern in the first example shown in FIG. This is the same irradiation pattern as when a is not irradiated. Hereinafter, the irradiation pattern shown in FIG. 9 is referred to as a second laser beam irradiation pattern in the conventional example.
[0015]
Then, the second laser beam irradiation in each of the first to sixth examples and the conventional example was performed a plurality of times, and each Y value was examined. The result shown in FIG. 7 was obtained. In this figure, the modification of the fifth example is that the energy density is appropriately lowered only at the irradiation end point indicated by the black circle in the irradiation pattern of the second laser beam in the fifth example shown in FIG. This is an example. White triangle marks indicate average values in each example.
[0016]
As is apparent from FIG. 7, in the case of the conventional example, all the Y values are 0.07 or more, the average value is about 0.09, and the light leakage is slightly large. On the other hand, in the modified examples of the first example, the third to sixth examples, and the fifth example, all the Y values are 0.07 or less. In the case of the second example, the Y value is slightly larger than 0.07, but the average value is smaller than 0.06. Therefore, the second laser beam, which is a common point between the first to sixth examples and the modified example of the fifth example, is continuously provided in a line along the peripheral portion of each side of the defective pixel 12 in a line shape. Upon irradiation Te, it is possible to further reduce light leakage.
[0017]
By the way, among the first to sixth examples, the average value of the Y values of the fifth example is about 0.05, which is the smallest. Therefore, the fifth example is the most desirable among the first to sixth examples. Therefore, comparing the fifth example with the first to fourth and sixth examples, the irradiation start point and the irradiation end point of the second laser beam are substantially in the center of the defective pixel 12, The laser beam irradiation points of 2 are continuous in a line from the irradiation start point to the irradiation end point, and the second laser beam irradiation points do not intersect anywhere.
[0018]
Therefore, in the case of the first example shown in FIG. 1, a part of the description will be given. After irradiating continuously from the lower right corner of the defective pixel 12 in the left direction, it is continuously irradiated in the upward direction by the pitch P. You may make it do. In the case of the second example shown in FIG. 2, a part of this will also be described. After irradiation continuously from the irradiation start point indicated by a white circle in the upper right corner of the defective pixel 12 in the left direction, You may make it irradiate continuously only the part of the pitch P to a direction. Furthermore, in the case of the third example shown in FIG. 3 as well, a part of this will be described. After irradiation along the periphery of the defective pixel 12, the rightmost irradiation line in the column direction is continuously irradiated. Then, a part of the irradiation line in the first row may be polymerized and irradiated. Here, in the modified example of the fifth example, the average value of the Y values is smaller than 0.05. Therefore, the modification of the fifth example is more desirable than the fifth example.
[0019]
In the above-described embodiment, the irradiation speed of the second laser beam is set such that the next irradiation area is approximately half of the previous irradiation area, or the previous irradiation area and the next irradiation area are separated from each other. It is good also as the speed of the grade. Further, it is possible to irradiate almost the entire circumference along the peripheral portion of the defective pixel by one laser irradiation.
[0020]
【The invention's effect】
As described above, according to the present invention, the irradiation pattern of the laser beam scans at least substantially the entire defective pixel, and the entire length of each pattern along the periphery of each side is linear. because it contains a first irradiation pattern which continuously irradiated with the second illumination pattern for scanning the inside, the defective pixel becomes always black display, it is possible to further reduce light leakage, thus The image quality can be further improved.
[Brief description of the drawings]
FIG. 1 is a diagram showing a second laser beam irradiation pattern in a first example of a defective pixel correction method for a liquid crystal display panel according to the present invention;
FIG. 2 is a diagram showing an irradiation pattern of a second laser beam in a second example.
FIG. 3 is a diagram showing an irradiation pattern of a second laser beam in a third example.
FIG. 4 is a diagram showing an irradiation pattern of a second laser beam in a fourth example.
FIG. 5 is a diagram showing an irradiation pattern of a second laser beam in a fifth example.
FIG. 6 is a diagram showing an irradiation pattern of a second laser beam in a sixth example.
FIG. 7 is a diagram showing the relationship between the second laser beam irradiation and the Y value in the first to sixth examples, the modified example of the fifth example, and the conventional example.
8A is a partial cross-sectional view of an example of a liquid crystal display panel, and FIG. 8B is a cross-sectional view similar to FIG. 8A showing a state in which bubbles are generated in the liquid crystal by irradiation with a first laser beam. .
FIG. 9 is a diagram showing an irradiation pattern of a conventional second laser beam.
[Explanation of symbols]
12 defective pixels

Claims (6)

A defect in a liquid crystal display panel in which a defective pixel portion of a liquid crystal display panel in which liquid crystal is sealed between a pair of substrates is irradiated with a laser beam to physically destroy the defective pixel portion, thereby correcting the defective pixel. In the pixel correction method, the irradiation pattern of the laser beam scans at least substantially the whole of the defective pixel, and the entire length is continuously irradiated in a line along the peripheral portion of each side. A defective pixel correction method for a liquid crystal display panel, comprising: a first irradiation pattern; and a second irradiation pattern for scanning the inside thereof . The laser beam according to claim 1, wherein the laser beam is irradiated along a peripheral portion of the defective pixel while changing an irradiation point in a first irradiation step for generating bubbles in the defective pixel portion. A defective pixel correction method for a liquid crystal display panel. In the invention of claim 2, wherein substantially a defective pixel correction of the liquid crystal display panel, which is a central portion of the second the laser beam irradiation starting point and part of the irradiation end point the defective pixel of the irradiation step Method. In the invention of claim 3, wherein, the defective pixel of the liquid crystal display panel, wherein the irradiation point of the laser beam at the second irradiation step is continuous to the irradiation end point to a line shape from the irradiation start point How to fix. 5. The defective pixel correction method for a liquid crystal display panel according to claim 4, wherein the energy density of the laser beam in the second irradiation step is low only at the irradiation end point. In the invention of claim 4, wherein defective pixel repairing method of a liquid crystal display panel, wherein the irradiation line of the laser beam at the second irradiation step is not even intersect anywhere.

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