JP2010256673A - Bright spot defect repairing method for liquid crystal display panel, and liquid crystal display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bright spot defect repairing method for a liquid crystal display panel, with which bright spot defects caused by various bright spot defect factors can be repaired and to provide the liquid crystal display panel to which the bright spot defect repairing method can be applied. <P>SOLUTION: The bright spot defect repairing method is applied to a liquid crystal display panel 1 including a pair of transparent substrates 3, 4 which face each other with a liquid crystal layer 2 sandwiched, and a plurality of spacers 5 dispersed between the transparent substrates 3, 4 and capable of displaying light shielding properties by the action of laser light 9. In the bright spot defect repairing method, a bright spot defect factor 6 between the transparent substrates 3, 4 is irradiated with laser light 9 to display the light shielding properties of the spacers 5 existing in the vicinity of the bright spot defect factor 6. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a bright spot defect repair method for a liquid crystal display panel and a liquid crystal display panel to which the bright spot defect repair method can be applied.

  Conventionally, liquid crystal display devices using liquid crystal in various operation modes such as a TN mode and an IPS mode are known. This type of liquid crystal display device includes a liquid crystal display panel including a liquid crystal layer and a pair of transparent substrates that face each other with the liquid crystal layer interposed therebetween. The pair of transparent substrates includes a light source side transparent substrate on which light from a light source included in the liquid crystal display device enters and a display side transparent substrate on which an image is displayed.

  As the pair of transparent substrates, for example, a TFT substrate (light source side transparent substrate) in which a plurality of thin film transistors (hereinafter referred to as “TFTs”) and pixel electrodes as switching elements are formed in a matrix on a transparent glass plate. ), And a CF substrate (display side transparent substrate) in which a plurality of color filter (hereinafter referred to as “CF”) layers and a common electrode are sequentially laminated on a transparent glass plate. The orientation of the liquid crystal layer sandwiched between the TFT substrate and the CF substrate is controlled by the electric field strength between the pixel electrode of the TFT substrate and the common electrode of the CF substrate facing the pixel electrode. By controlling the orientation of the liquid crystal layer in this way, the amount of light emitted from the light source to the liquid crystal display panel is adjusted.

  The liquid crystal display panel forms an image using a large number of pixels (for example, hundreds of thousands to millions of pixels), and it is desired that all the pixels function correctly. However, since the liquid crystal display panel is manufactured through a complicated manufacturing process, it may include some defective pixels.

  As the defective pixel, even in a liquid crystal display device during black display, light may leak in a dotted manner from the display-side transparent substrate of the liquid crystal display panel. This defective pixel is known as a so-called “bright spot (bright spot defect)” and has been regarded as a problem because it causes a reduction in image quality of the liquid crystal display panel.

  It is known that the bright spot is generated due to various causes (bright spot defect factor). For example, when a foreign substance enters the liquid crystal layer between the transparent substrates of the liquid crystal display panel, light is reflected / refracted by the mixed foreign substance, and the reflected light leaks from the transparent substrate on the display side, thereby generating a bright spot. is there.

  Also, if conductive foreign matter enters the liquid crystal layer, the electrodes between the transparent substrates where the foreign matter enters may be electrically short-circuited, and the liquid crystal layer (liquid crystal) at that location may not be controllable. . In that case, even if the liquid crystal display device displays black, the light from the light source passes through the liquid crystal layer (liquid crystal) whose alignment cannot be controlled, leaks from the display side transparent substrate of the liquid crystal display panel, and a bright spot is generated. There is. In addition, foreign matter mixed in the liquid crystal layer itself becomes an obstacle, and the alignment behavior of the liquid crystal layer (liquid crystal) in the vicinity of the foreign matter is hindered. As a result, the light from the light source passes through the vicinity of the foreign matter and a bright spot is generated. There is also. In addition to these, bright spots are also caused by switching element defects (TFT defects), electrode defects, and the like of the transparent substrate.

  As a method for repairing the bright spot of such a liquid crystal display panel, for example, as disclosed in Patent Document 1, a transparent substrate (specifically, a laser beam is irradiated on the display side transparent substrate of the liquid crystal display panel. There is a method of changing the transmittance of a transparent glass plate included in a transparent substrate to make the bright spot inconspicuous. In this bright spot repairing method, a laser beam is irradiated to a portion where the bright spot of the display-side transparent substrate appears. This bright spot repair method makes the bright spot of the liquid crystal display panel inconspicuous by making the transmittance of the transparent substrate where the laser beam is irradiated lower than the transmittance of the transparent substrate in other places. That's it.

  Patent Document 1 shows that this bright spot repair method can repair bright spot defects caused by various causes such as defects in switching elements and foreign substances in the liquid crystal layer.

JP 2008-233666 A

  However, the bright spot repair method directly processes the glass plate of the display-side transparent substrate of the liquid crystal display panel with laser light, and may damage the film surface of the transparent substrate in addition to the transmittance of the glass plate. There is a problem.

  In addition, when a foreign substance is mixed in the liquid crystal layer of the liquid crystal display panel, the light from the light source may be reflected or refracted in various directions by the foreign substance. In such a case, the reflected / refracted light leaks in various directions from the display surface (display-side transparent substrate) of the liquid crystal display panel during black display, and as a result, the bright spot is visible from various angles. become. Then, not only when the liquid crystal display panel during black display is viewed from the front, but also when the liquid crystal display panel is viewed from an oblique direction, bright spots are recognized.

  In such a case, if the display-side transparent substrate is repaired by the bright spot repair method so that the bright spot is not recognized when the display surface of the liquid crystal display panel is viewed not only from the front but also from an oblique direction, the repair is performed. The part of the transparent substrate that must be done becomes long and large. When the repaired portion becomes large, the repaired portion becomes noticeable black when the liquid crystal display panel is brightly displayed.

  An object of the present invention is to provide a bright spot defect repair method for a liquid crystal display panel that can repair bright spot defects based on various bright spot defect factors, and a liquid crystal display panel to which the bright spot defect repair method can be applied. .

  A method for repairing a bright spot defect of a liquid crystal display panel according to the present invention includes a pair of transparent substrates facing each other with a liquid crystal layer interposed therebetween, and a plurality of transparent substrates that are dispersed and interposed between the transparent substrates and exhibit light shielding properties by the action of laser light. A bright spot defect repairing method for a liquid crystal display panel comprising a spacer, and irradiating a laser beam toward a bright spot defect factor between the transparent substrates to exhibit a light shielding property of the spacer in the vicinity of the bright spot defect factor It is characterized by that.

  In the bright spot defect repairing method of the liquid crystal display panel, it is preferable that the spacer exhibits adhesiveness by the action of laser light.

  The liquid crystal display panel of the present invention includes a pair of transparent substrates facing each other with a liquid crystal layer interposed therebetween, and a plurality of spacers that are dispersed and interposed between the transparent substrates and receive a laser beam to exhibit a light shielding property. It is characterized by.

  In the liquid crystal display panel, for example, the spacer includes an adhesive and a colorant.

  According to the bright spot defect repair method for a liquid crystal display panel of the present invention, bright spot defects based on various bright spot defect factors can be repaired. Further, the liquid crystal display panel of the present invention can repair a bright spot defect by the bright spot defect repairing method even if a bright spot defect based on various bright spot defect factors occurs.

It is explanatory drawing which shows the liquid crystal display panel which concerns on one Embodiment of this invention. It is explanatory drawing which shows the liquid crystal display panel which concerns on one Embodiment containing a luminescent spot defect. FIG. 3 is an explanatory view showing a step of irradiating a laser beam toward a bright spot defect factor of the liquid crystal display panel shown in FIG. 2 in the bright spot defect repairing method for a liquid crystal display panel according to an embodiment of the present invention. It is explanatory drawing which shows the liquid crystal display panel by which the bright spot defect was repaired with the bright spot defect repair method of the liquid crystal display panel shown by FIG. It is explanatory drawing which shows the liquid crystal display panel which concerns on other embodiment containing a luminescent spot defect. FIG. 6 is an explanatory view showing a step of irradiating a laser beam toward a bright spot defect factor of the liquid crystal display panel shown in FIG. 5 in a liquid crystal display panel bright spot defect repairing method according to another embodiment of the present invention. It is explanatory drawing which shows the liquid crystal display panel by which the bright spot defect was repaired with the bright spot defect repair method of the liquid crystal display panel shown by FIG.

  Hereinafter, a bright spot defect repair method for a liquid crystal display panel according to an embodiment of the present invention and a liquid crystal display panel to which the bright spot defect repair method can be applied will be described with reference to the drawings. However, the present invention is not limited to the embodiments exemplified in this specification.

[LCD panel]
FIG. 1 is an explanatory diagram showing a liquid crystal display panel 1 according to an embodiment of the present invention. The liquid crystal display panel 1 is used for a so-called transmissive liquid crystal display device. As shown in FIG. 1, the liquid crystal display panel 1 includes a liquid crystal layer 2, a pair of transparent substrates 3 and 4, and a spacer 5.

  The liquid crystal layer 2 is made of a known liquid crystal material, and the pair of transparent substrates 3 and 4 are arranged facing each other so as to sandwich the liquid crystal layer 2. Of the pair of transparent substrates 3 and 4, light from a light source (backlight) (not shown) is incident on one transparent substrate 4. In the present embodiment, the transparent substrate 4 on the light incident side is particularly referred to as a light source side transparent substrate, and the other transparent substrate 3 is particularly referred to as a display side transparent substrate. The display-side transparent substrate 3 becomes a display surface of the liquid crystal display panel 1 and displays an image. The image is visually recognized from the outside.

The light source side transparent substrate 4 is a so-called TFT substrate in which a plurality of TFTs (not shown), pixel electrodes (not shown) and the like are formed on a transparent glass plate 14. The light source side transparent substrate 4 includes a polarizing plate, a retardation plate, an alignment film, etc. (not shown) in addition to the TFT and the like.
The display-side transparent substrate 3 is a so-called CF substrate in which a plurality of color CF layers (not shown), a common electrode (not shown), and the like are sequentially laminated on a transparent glass plate 13. The display-side transparent substrate 3 includes a polarizing plate, a retardation plate, an alignment film, and the like (not shown) in addition to the CF layer and the like.

  The spacers 5 are dispersed and interposed between the display side transparent substrate 3 and the light source side transparent substrate 4. A plurality of the spacers 5 exist between the transparent substrates 3 and 4, and the distance (interval) between the transparent substrates 3 and 4 is kept constant. At the same time, the spacer 5 exhibits light shielding properties by the action of laser light.

The spacer 5 may exhibit light shielding properties as a whole by the action of laser light, or a part of the spacer 5 (for example, a colorant) may exhibit light shielding properties.
The “light blocking property” that the spacer 5 develops is most preferably one that completely blocks light from the light source (backlight), but is not limited thereto. The “light-shielding property” is not limited as long as the spacer 5 absorbs light from the light source at least by the action of the laser light to make the bright spot appear dark.

  The spacer 5 is preferably one that exhibits adhesiveness (thermoplasticity) as well as light shielding properties by the action of laser light.

Examples of the spacer 5 include a coloring agent and an outer shell made of a thermoplastic resin enclosing the coloring agent. Examples of the colorant include pigments, dyes, and the like, and in particular, a colorant that develops color and exhibits light shielding properties by the action of laser light is preferable. In addition to the colorant 5, the adhesive 5 may be included in the outer shell. The shape of the spacer 5 is not particularly limited and may be appropriately selected depending on the purpose.
The spacer 5 may be a dispersion of the colorant in a thermoplastic resin.

  In this embodiment, all the spacers 5 exhibit light shielding properties by the action of laser light, but in other embodiments, other spacers 5 are used in this type of liquid crystal display panel. Alternatively, a known spacer (known spacer) may be used.

  In the liquid crystal display panel 1 of the present embodiment, as described above, the spacers 5 that exhibit light blocking properties by the laser light are dispersed and interposed between the transparent substrates 3 and 4. For this reason, in the liquid crystal display panel 1, even if a bright spot defect occurs due to foreign matter or the like mixed in the liquid crystal layer 2, the light shielding property of the spacer 5 existing in the vicinity of the bright spot defect is expressed by the action of the laser beam. By doing so, the bright spot defect can be darkened and repaired.

  In another embodiment, the liquid crystal display panel may be used for a liquid crystal device device of another display format such as a reflective liquid crystal display device or a projection liquid crystal display device.

  Hereinafter, a bright spot defect repair method for the liquid crystal display panel 1 will be described with reference to the drawings.

[Liquid spot defect repair method for LCD panels]
FIG. 2 is an explanatory diagram showing a liquid crystal display panel 1 according to an embodiment including a bright spot defect. The liquid crystal display panel 1 shown in FIG. 2 has a defective TFT 6 that is a bright spot defect factor on the light source side transparent substrate 3, and a bright spot ( (Bright spot defect) 8 occurs. The basic configuration of the liquid crystal display panel 1 shown in FIG. 2 is the same as that shown in FIG. 1, and the description of each configuration is omitted.

  As shown in FIG. 2, the liquid crystal display panel 1 at the time of black display usually has a display side after light 7 (7a) from a light source (not shown) passes through the light source side transparent substrate 4 and the liquid crystal layer 2. It is absorbed by a polarizing plate (not shown) of the transparent substrate 3. However, if there is a defective TFT 6 that is a bright spot defect factor on the light source side transparent substrate 3, the alignment control of the liquid crystal layer 2 (liquid crystal molecules) in the vicinity of the defective TFT 6 cannot be performed. Therefore, as shown in FIG. 2, the light 7 (7b) from the light source (not shown) passes through the light source side transparent substrate 4 and the liquid crystal layer 2, and further passes through the display side transparent substrate 3 to be transparent on the display side. It appears as a bright spot (bright spot defect) 8 on the substrate 3.

  In the present specification, “bright spot defect factor” means that a bright spot (bright spot defect) is generated on one transparent substrate (display-side transparent substrate 3) even when the liquid crystal display panel displays black. Such factors as foreign matter, defective TFT, defective electrode, and the like.

  FIG. 3 is an explanatory diagram showing a step of irradiating laser light toward the bright spot defect factor of the liquid crystal display panel 1 shown in FIG. 2 in the bright spot defect repairing method for the liquid crystal display panel according to one embodiment of the present invention. It is. As shown in FIG. 3, laser beams 9 and 9 are irradiated from two directions toward the defective TFT 6 which is a bright spot defect factor of the liquid crystal display panel. When the laser beams 9 and 9 are irradiated, the spacer 5 in the vicinity of the defective TFT 6 is blackened by the action of the laser beam 9 and the light-shielding property is developed. The defective TFT 6 that is a bright spot defect factor is surrounded by a spacer 5 that exhibits light shielding properties.

  The spacer 5 that receives the action of the laser light 9 preferably exhibits light shielding properties and also exhibits adhesiveness (thermoplasticity).

  FIG. 4 is an explanatory diagram showing a liquid crystal display panel in which the bright spot defects are repaired by the bright spot defect repairing method of the liquid crystal display panel shown in FIG. As shown in FIG. 4, the defective TFT 6 that is a bright spot defect factor is covered with a covering 15 made of a spacer 5 that exhibits light shielding properties and exhibits adhesiveness (plasticity) by the action of laser light. When the defective TFT 6 is covered with the light-shielding covering 15 as described above, the bright spot (bright spot defect) 8 generated by the defective TFT 6 becomes dark (turned to a black spot) and repaired.

  Note that the wavelength, intensity, and the like of the laser beam 9 to be irradiated are appropriately selected in consideration of the material of the spacer 5 and the like. In other embodiments, the laser beam 9 may be irradiated from only one direction, or may be irradiated from three or more directions, and there is no particular limitation.

  FIG. 5 is an explanatory view showing a liquid crystal display panel according to another embodiment including a bright spot defect. The liquid crystal display panel 11 shown in FIG. 5 has the same configuration as that of the liquid crystal display panel 1 shown in FIG. 1 except that the liquid crystal layer 2 contains foreign matter 16 as a bright spot defect factor. Therefore, description of each component of the liquid crystal display panel 11 shown in FIG. 5 is omitted.

  As shown in FIG. 5, when the foreign matter 16 that is a bright spot defect factor is present in the liquid crystal layer 2, the light 7 (7c) from the light source (not shown) is refracted by the foreign matter 16 and travels. The direction may be changed toward the display-side transparent substrate 3. When such a foreign matter 16 is present in the liquid crystal layer 2, the light 7 (7 c) passes through the display-side transparent substrate 3 in the liquid crystal display panel 11 during black display, and a bright spot (brightness) is displayed on the display-side transparent substrate 3. Appears as 18). In this case, the bright spot (bright spot defect) 18 does not appear in a direction perpendicular to the substrate surface (display surface) of the display-side transparent substrate 3 from the foreign matter 16 but is located slightly away from the perpendicular direction. Will appear.

  FIG. 6 is an explanatory diagram showing a step of irradiating laser light toward the bright spot defect factor of the liquid crystal display panel 11 shown in FIG. 5 in the method for repairing bright spot defects of the liquid crystal display panel according to one embodiment of the present invention. It is. As shown in FIG. 6, the laser beams 9 and 9 are irradiated from two directions toward the foreign material 16 which is a bright spot defect factor of the liquid crystal display panel. When the laser beam 9 is irradiated, the spacer 5 in the vicinity of the foreign matter 16 is blackened by the action of the laser beam 9 to cause the colorant contained in the spacer 5 to appear, thereby exhibiting light shielding properties. The foreign matter 16 that is a bright spot defect factor is surrounded by the spacer 5 that exhibits light shielding properties.

  The spacer 5 that receives the action of the laser light 9 preferably exhibits light shielding properties and also exhibits adhesiveness (thermoplasticity).

  FIG. 7 is an explanatory diagram showing a liquid crystal display panel in which bright spot defects are repaired by the bright spot defect repairing method of the liquid crystal display panel shown in FIG. As shown in FIG. 7, the foreign matter 16 that is a bright spot defect factor is covered with a covering 15 made of a spacer 5 that exhibits light shielding properties and exhibits adhesiveness (plasticity) by the action of laser light. As described above, when the foreign matter 16 is covered with the light-shielding covering 15, the bright spot (bright spot defect) 18 generated by the foreign matter 16 becomes dark (darkened) and is repaired.

  In another embodiment, a spacer that exhibits only adhesiveness (thermoplasticity) by the action of laser light may be used. The spacer may fix liquid crystal molecules in the vicinity of the bright spot defect factor on the transparent substrate.

  In another embodiment, in order to repair the bright spot (bright spot defect) of the display-side transparent substrate of the liquid crystal display panel, the inner side (liquid crystal layer side) of the display-side transparent substrate where the bright spot appears is irradiated with laser light. You may coat | cover with the spacer which expressed light-shielding property.

  The laser light may be irradiated from the display side transparent substrate side of the liquid crystal display panel or from the light source side transparent substrate side.

1 Liquid Crystal Display Panel 2 Liquid Crystal Layer 3 Transparent Substrate (Display Side Transparent Substrate)
4 Transparent substrate (transparent substrate on the light source side)
5 Spacer 6 Defective TFT (Bright spot defect factor)
7 (7a, 7b, 7c) Light from light source 8 Bright spot (bright spot defect)
9 Laser beam 11 Liquid crystal display panel 13 Glass plate 14 Glass plate 15 Cover 16 Foreign matter (bright spot defect factor)
18 Bright spot (Bright spot defect)

Claims (4)

A pair of transparent substrates facing each other across the liquid crystal layer;
A method for repairing a bright spot defect in a liquid crystal display panel comprising a plurality of spacers that are dispersed and interposed between the transparent substrates and exhibit a light shielding property by the action of laser light,
A method for repairing a bright spot defect in a liquid crystal display panel, characterized by irradiating a laser beam toward a bright spot defect factor between the transparent substrates to develop a light shielding property of a spacer near the bright spot defect factor.   The method for repairing a bright spot defect in a liquid crystal display panel according to claim 1, wherein the spacer exhibits adhesiveness by the action of laser light. A pair of transparent substrates facing each other across the liquid crystal layer;
A liquid crystal display panel, comprising: a plurality of spacers that are dispersed and interposed between the transparent substrates and receive a laser beam to exhibit a light shielding property.   The liquid crystal display panel according to claim 3, wherein the spacer includes an adhesive and a colorant.

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