WO2012096187A1 - Method for manufacturing liquid crystal display device, and liquid crystal display device manufactured by the method - Google Patents

Abstract

A liquid crystal display panel (14) that is configured of a TFT substrate (11), which is provided on the display light incident side and has a glass substrate (21), and a CF substrate (12), which is provided on the display light exit side so as to face the TFT substrate (11) with a liquid crystal layer (13) being interposed therebetween, and that has a bright defect (18) due to a foreign substance (16) included in the liquid crystal layer (13) is prepared. Next, a through hole (2) is formed in a region of the glass substrate (21), said region corresponding to the bright defect (18). The foreign substance (16) is removed via the through hole (2).

Description

Method for manufacturing liquid crystal display device and liquid crystal display device manufactured by the method

The present invention relates to a manufacturing method of a liquid crystal display device in which a pair of substrates are overlapped at a predetermined interval and a liquid crystal layer is sealed in a gap between the pair of substrates, and a liquid crystal display device manufactured by the method.

In recent years, as a display panel for mobile terminal devices such as mobile phones and portable game machines and various electronic devices such as notebook computers, it has the advantages of being thin and lightweight, being able to be driven at a low voltage, and consuming little power. Liquid crystal display panels are widely used.

In general, a liquid crystal display panel includes, for example, a TFT (Thin Film Transistor) substrate in which a plurality of pixel electrodes are arranged in a matrix, and a CF (Color Filter) substrate having a common electrode disposed facing the TFT substrate. And a liquid crystal layer provided between the TFT substrate and the CF substrate. A liquid crystal display panel is manufactured by fabricating a TFT substrate and a CF substrate, then bonding the two substrates together to produce an empty panel, and injecting and sealing a liquid crystal material between the substrates constituting the panel. The Then, the manufactured liquid crystal display panel is subjected to product inspection such as lighting inspection.

Further, in this lighting inspection, for example, an inspection signal is input to all the pixel electrodes of the TFT substrate and the common electrode of the CF substrate to turn on all the pixels, and from the back side of the liquid crystal display panel. A pixel that is short-circuited by a conductive foreign substance between the pixel electrode and the common electrode (that is, the liquid crystal layer) by applying light from the backlight, that is, a defective pixel (defective pixel) serves as a bright spot. Detected. In the liquid crystal display panel in which the bright spot is detected, the bright spot causes a display defect.

In addition, as a technique for dealing with such a display defect, for example, the tip is pointed at the surface position of the glass substrate constituting the TFT substrate and optically overlapping the portion where the bright spot defect occurs. A liquid crystal display in which a concave portion is formed by pressing the tip of a carbide drill (a pen tip equipped with a diamond head) and cutting the glass substrate, and a light shielding material is provided in the concave portion. A panel is disclosed. And, according to this, it is described that the bright spot defect can be corrected without requiring any special apparatus or complicated work, and without causing defects such as bubbles generated between the polarizing plate and the liquid crystal panel. (For example, refer to Patent Document 1).

JP 2005-189360 A

Here, when a large foreign matter having a diameter larger than the thickness of the liquid crystal layer (that is, the cell gap) is interposed in the liquid crystal layer, the cell gap changes, and light leaks from the portion where the foreign matter is interposed and shines. Therefore, as described in Patent Document 1, the method of simply providing the light shielding material in the recess has a disadvantage that the bright spot cannot be corrected sufficiently.

Accordingly, the present invention has been made in view of the above-mentioned problems, and a liquid crystal display device including a liquid crystal display panel including a foreign substance having a diameter larger than the thickness of the liquid crystal layer is regenerated without being discarded, and the yield is increased. An object of the present invention is to provide a method of manufacturing a liquid crystal display device capable of improving the quality of the liquid crystal display device and a liquid crystal display device manufactured by the method.

In order to achieve the above object, a first liquid crystal display device manufacturing method of the present invention is provided on a light incident side of display light, and includes a first substrate having a glass substrate, a first substrate, and a liquid crystal layer. A step of preparing a liquid crystal display panel having a bright spot defect portion caused by a foreign substance interposed in the liquid crystal layer, and a second substrate provided on the display light emitting side so as to face each other; The method includes at least a step of forming a through hole in a region corresponding to a point defect portion, a step of removing foreign matter through the through hole, and a step of filling a resin into the through hole to form a resin filling portion. It is characterized by that.

According to this configuration, even if a large foreign matter having a diameter larger than the thickness of the liquid crystal layer is present in the liquid crystal layer, the foreign matter is removed, so the change in cell gap caused by the foreign matter is eliminated. In the liquid crystal layer, the cell gap can be made uniform. Therefore, in a liquid crystal display device including a liquid crystal display panel in which a defective pixel due to a large foreign matter is detected as a bright spot, it is possible to reliably correct the bright spot defect. As a result, a liquid crystal display device including a liquid crystal display panel in which defective pixels are detected as bright spots can be regenerated without being discarded, and the yield of the liquid crystal display device can be improved.

In the first method for manufacturing a liquid crystal display device of the present invention, in the step of removing foreign matter, the foreign matter may be removed by sucking the foreign matter and extracting the foreign matter from the liquid crystal layer.

According to this configuration, the foreign matter is removed by sucking the foreign matter and removing the foreign matter from the liquid crystal layer, so that the foreign matter present in the liquid crystal layer can be reliably removed.

In the first method for producing a liquid crystal display device of the present invention, the resin may be a transparent resin.

According to the same configuration, since the resin filled in the through hole is transparent, it is possible to prevent the light shielding region due to the filling of the resin from being formed in the liquid crystal display panel. Therefore, the bright spot defect can be corrected without causing a decrease in the aperture ratio.

In the first liquid crystal display device manufacturing method of the present invention, the transparent resin may be a polycarbonate resin.

According to the same configuration, the resin-filled portion can be formed from an inexpensive and versatile resin.

According to the second method of manufacturing the liquid crystal display device of the present invention, the display light is provided on the incident side of the display light, and the first substrate having a glass substrate is opposed to the first substrate through the liquid crystal layer. A step of preparing a liquid crystal display panel having a bright spot defect portion caused by a foreign substance interposed in the liquid crystal layer, and a region corresponding to the bright spot defect portion of the glass substrate. It includes at least a step of forming a through hole, a step of crushing foreign matter through the through hole, and a step of forming a light shielding portion by filling the through hole with a light shielding material.

According to this configuration, even when a large foreign matter having a diameter larger than the thickness of the liquid crystal layer is present in the liquid crystal layer, the foreign matter is crushed, so the change in cell gap caused by the foreign matter is eliminated. In the liquid crystal layer, the cell gap can be made uniform. Therefore, in a liquid crystal display device including a liquid crystal display panel in which a defective pixel due to a large foreign matter is detected as a bright spot, it is possible to reliably correct the bright spot defect. As a result, a liquid crystal display device including a liquid crystal display panel in which defective pixels are detected as bright spots can be regenerated without being discarded, and the yield of the liquid crystal display device can be improved.

In the second method for manufacturing a liquid crystal display device of the present invention, the foreign matter may be crushed with a drill stick in the step of crushing the foreign matter.

According to this configuration, since the foreign matter is crushed by the drill stick, the foreign matter present in the liquid crystal layer can be reliably crushed.

According to the present invention, it is possible to regenerate without discarding a liquid crystal display device including a liquid crystal display panel in which defective pixels caused by large foreign matters having a diameter larger than the thickness of the liquid crystal layer are detected as bright spots. This makes it possible to improve the yield of the liquid crystal display device.

1 is a cross-sectional view of a liquid crystal display device according to a first embodiment of the present invention. It is sectional drawing for demonstrating the manufacturing process of the liquid crystal display device which concerns on the 1st Embodiment of this invention. It is sectional drawing for demonstrating the manufacturing process of the liquid crystal display device which concerns on the 1st Embodiment of this invention. It is sectional drawing for demonstrating the manufacturing process of the liquid crystal display device which concerns on the 1st Embodiment of this invention. It is sectional drawing for demonstrating the manufacturing process of the liquid crystal display device which concerns on the 1st Embodiment of this invention. It is sectional drawing of the liquid crystal display device which concerns on the 2nd Embodiment of this invention. It is sectional drawing for demonstrating the manufacturing process of the liquid crystal display device which concerns on the 2nd Embodiment of this invention. It is sectional drawing for demonstrating the manufacturing process of the liquid crystal display device which concerns on the 2nd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following embodiment.

(First embodiment)
FIG. 1 is a cross-sectional view of a liquid crystal display device according to the first embodiment of the present invention. As shown in FIG. 1, the liquid crystal display device 1 includes a liquid crystal display panel 14 and a backlight 15.

The liquid crystal display panel 14 includes a TFT substrate 11 that is a first substrate provided on the incident side of display light by the backlight 15, a CF substrate 12 that is a second substrate facing the TFT substrate 11, a TFT substrate 11, A liquid crystal layer 13 which is a display medium layer provided between the CF substrates 12 and a sealing material 25 provided in a frame shape for adhering the TFT substrate 11 and the CF substrate 12 to each other and enclosing the liquid crystal layer 13 are provided. I have.

The sealing material 25 is formed so as to go around the liquid crystal layer 13, and the TFT substrate 11 and the CF substrate 12 are bonded to each other via the sealing material 25. The CF substrate 12 is provided on the display light emitting side so as to face the TFT substrate 11 with the liquid crystal layer 13 interposed therebetween.

The TFT substrate 11 includes a glass substrate 21, TFT elements each having a gate electrode, a source electrode and a drain electrode (not shown) formed on the glass substrate 21, a transparent insulating layer, a pixel electrode, an alignment film, and the like. The back polarizing plate 17 is formed on the outer surface.

In addition, as the glass substrate 21, for example, non-alkali glass not containing alkali metal such as sodium, aluminosilicate glass, aluminoborosilicate glass, or the like can be used. Further, the thickness of the glass substrate 21 is, for example, 200 μm to 700 μm.

The CF substrate 12 includes, for example, a black matrix (not shown) provided on the glass substrate 22 in a lattice shape and a frame shape as a light shielding portion, and a red layer, a green layer, and a blue layer provided between the lattices of the black matrix, respectively. And a color filter (not shown) including a colored layer such as a layer. The CF substrate 12 covers a common electrode (not shown) provided so as to cover the black matrix and the color filter, a photo spacer (not shown) provided in a column shape on the common electrode, and a common electrode. And an alignment film (not shown) provided.

The CF substrate 12 has a surface polarizing plate 19 formed on the outer surface thereof. In addition, as the glass substrate 22, the thing similar to the above-mentioned glass substrate 21 can be used. Further, the thickness of the glass substrate 22 is, for example, 200 μm to 700 μm, similarly to the glass substrate 21 described above.

The liquid crystal layer 13 is made of, for example, a nematic liquid crystal material having electro-optical characteristics. The thickness of the liquid crystal layer 13 is, for example, 2 μm to 4 μm.

The backlight 15 is disposed on the TFT substrate 11 side of the liquid crystal display panel 14. The backlight 15 receives a light source, light emitted from the light source, a light guide plate that emits light toward the liquid crystal display panel 14 while propagating through the light source, and light emitted from the back surface of the light guide plate. And a reflecting plate (all not shown) that reflects toward the light guide plate.

Next, a method for manufacturing the liquid crystal display device 1 according to the present embodiment will be described with reference to the drawings. 2 to 5 are cross-sectional views for explaining a manufacturing process of the liquid crystal display device according to the first embodiment of the present invention.

First, after patterning TFT elements and pixel electrodes on the glass substrate 21 to form a TFT array layer constituting the display area, a polyimide resin is applied to the entire substrate by a printing method, and then a rubbing process is performed. Then, an alignment film is formed, and the TFT substrate 11 is manufactured.

Further, a color filter including a colored layer and a black matrix, a common electrode, and the like are patterned on the glass substrate 22 to form a CF element layer constituting a display region, and then a polyimide resin is applied to the entire substrate by a printing method. The CF substrate 12 is manufactured by applying and then rubbing to form an alignment film. Next, for example, spherical silica or plastic particles are dispersed over the entire substrate to form spacers.

Next, using a dispenser, a sealing material 25 made of ultraviolet curing and thermosetting resin or the like is drawn on the CF substrate 12 in a frame shape.

Next, a liquid crystal material is dropped onto a region inside the sealing material 25 in the CF substrate 12 on which the sealing material 25 is drawn.

Further, the CF substrate 12 onto which the liquid crystal material is dropped and the TFT substrate 11 are bonded together under reduced pressure.

Next, the front and back surfaces of the bonded body are pressurized by releasing the bonded body to atmospheric pressure. Then, after irradiating the sealing material 25 sandwiched between the bonded bodies with UV light, the sealing material 25 is cured by heating the bonded body.

Then, a back polarizing plate 17 is provided on the outer surface of the TFT substrate 11, and a front polarizing plate 19 is provided on the outer surface of the CF substrate 12.

Thus, the liquid crystal display panel 14 is manufactured.

Next, a lighting inspection is performed on the liquid crystal display panel 14 to inspect the presence or absence of light leakage of the backlight. More specifically, for example, an inspection signal is input to all the pixel electrodes of the TFT substrate 11 and the common electrode of the CF substrate 12 to turn on all the pixels. Further, light from the backlight 15 is irradiated from the back side of the liquid crystal display panel 14 (that is, the TFT substrate 11 side). Then, as shown in FIG. 2, when there is a pixel short-circuited with a large foreign material 16 having a diameter R larger than the thickness T of the liquid crystal layer 13 between the pixel electrode and the common electrode, Light from the backlight 15 leaks from a certain pixel, and a defective pixel is detected as a bright spot.

Next, as shown in FIG. 2, a marking 20 is applied to a region on the outer surface of the TFT substrate 11 (that is, the surface 21a of the glass substrate 21) corresponding to the position where light leakage occurs. And the bright spot defect part 18 is pinpointed with respect to the part of this marking 20 using a polarizing plate.

Next, as shown in FIG. 4, the surface of the glass substrate 21 provided on the TFT substrate 11 is the surface opposite to the liquid crystal layer 13 side, and the bright spot defect portion 18 in the liquid crystal layer 13 (that is, the position of the foreign matter 16). ) Is formed in the region corresponding to (i.e., the surface position optically overlapping the bright spot defect portion 18).

Here, in the present embodiment, the above-described through hole 2 is formed by grinding the glass substrate 21 with, for example, a carbide drill or an electrodeposition grindstone. More specifically, as shown in FIG. 3, the through-hole 2 is formed by, for example, pressing the carbide drill 7 against the surface 21a of the glass substrate 21 while performing a grinding operation.

Next, as shown in FIG. 5, the foreign material 16 is sucked using the stick-like suction device 26 and the foreign material 16 is removed from the liquid crystal layer 13, thereby removing the foreign material 16 interposed in the liquid crystal layer 13. At this time, since the intervening foreign matter 16 is removed from the liquid crystal layer 13, the change in the cell gap due to the foreign matter 16 is eliminated, and the cell gap becomes uniform in the liquid crystal layer 13.

After removing the foreign matter 16, the through-hole 2 is filled with a transparent resin (for example, polycarbonate resin) and cured by heating or standing at room temperature, as shown in FIG. The resin filling part 3 is formed inside.

From the above, the liquid crystal display device shown in FIG. 1 is manufactured.

According to the present embodiment described above, the following effects can be obtained.

(1) In the present embodiment, the through hole 2 is formed in a region corresponding to the bright spot defect portion 18 of the glass substrate 21, and the foreign matter 16 is removed through the through hole 2. Accordingly, even when a large foreign matter 16 having a diameter R larger than the thickness T of the liquid crystal layer 13 is present in the liquid crystal layer 13, the change in cell gap caused by the foreign matter 16 is removed in order to remove the foreign matter 16. Is eliminated, and the cell gap can be made uniform in the liquid crystal layer 13. Therefore, in the liquid crystal display device 1 including the liquid crystal display panel 14 in which a defective pixel due to the large foreign matter 16 is detected as a bright spot, the bright spot defect can be reliably corrected. As a result, the liquid crystal display device 1 including the liquid crystal display panel 14 in which defective pixels are detected as bright spots can be regenerated without being discarded, and the yield of the liquid crystal display device 1 can be improved. become.

(2) In this embodiment, the foreign matter 16 is removed by sucking the foreign matter 16 and extracting the foreign matter 16 from the liquid crystal layer 13. Accordingly, it is possible to reliably remove the foreign matter 16 present in the liquid crystal layer 13.

(3) In the present embodiment, a transparent resin is used as the resin filling the through hole 2. Therefore, it is possible to prevent the light shielding region due to the filling of the resin from being formed in the liquid crystal display panel 14. As a result, it is possible to correct the bright spot defect without causing a decrease in the aperture ratio.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. FIG. 6 is a cross-sectional view of a liquid crystal display device according to the second embodiment of the present invention. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. Further, the overall configuration of the liquid crystal display device is the same as that described in the first embodiment, and therefore detailed description thereof is omitted here.

In the first embodiment, the through hole 2 is formed in the glass substrate 21 of the TFT substrate 11, and the foreign material 16 is removed by sucking the foreign material through the through hole 2. In FIG. 6, instead of removing the foreign matter 16, the foreign matter 16 is crushed through the through hole 2.

Further, in the present embodiment, unlike the first embodiment described above, foreign matter remains in the liquid crystal layer 13, so that a light shielding portion 4 made of a light shielding material is formed in the through hole 2.

More specifically, as shown in FIG. 6, the through hole 2 is formed in a region corresponding to the bright spot defect portion 18 in the liquid crystal layer 13 of the glass substrate 21 included in the TFT substrate 11. A light shielding portion 4 made of a light shielding material is formed in 2.

The light shielding portion 4 covers the bright spot defect portion 18 of the glass substrate 21 in a plan view so that incident light (display light) from the backlight 15 placed on the back surface does not reach the bright spot defect portion 18. Is formed.

Further, the light shielding portion 4 is formed in a cylindrical shape extending from the outer surface of the glass substrate 21 in the thickness direction. The light shielding portion 4 is formed of a light shielding material such as a resin having a light shielding property such as black (for example, epoxy resin).

The light shielding portion 4 is not limited to the shape described above, and may have any shape as long as it covers the bright spot defect portion 18 in the liquid crystal layer 13.

Next, a method for manufacturing the liquid crystal display device 1 according to the present embodiment will be described with reference to the drawings. FIG. 7 is a cross-sectional view for explaining a manufacturing process of the liquid crystal display device according to the second embodiment of the present invention.

First, similarly to the first embodiment described above, the liquid crystal display panel 14 is manufactured, the lighting inspection is performed on the liquid crystal display panel 14, and the presence or absence of light leakage of the backlight light is inspected.

Next, in the same manner as in the first embodiment described above, the through hole 2 for crushing the foreign matter 16 in the region corresponding to the bright spot defect portion 18 in the liquid crystal layer 13 of the glass substrate 21 provided in the TFT substrate 11. Form.

Next, as shown in FIG. 7, the foreign matter 16 interposed in the liquid crystal layer 13 is removed from the liquid crystal layer 13 by the drill stick 27 through the through hole 2 (that is, the TFT substrate 11 side). To the CF substrate 12 side (that is, in the direction of the arrow in the figure) to crush the foreign matter 16.

At this time, since the intervening foreign matter 16 is crushed in the liquid crystal layer 13, the diameter of the foreign matter 16 becomes smaller than the thickness of the liquid crystal layer 13. Accordingly, the change in the cell gap due to the foreign matter 16 is eliminated, and the cell gap becomes uniform in the liquid crystal layer 13.

After the foreign matter 16 is crushed, the above-described light shielding material is filled in the through-hole 2 and cured by heating or standing at room temperature, thereby, as shown in FIG. The light shielding part 4 is formed.

When the display light is incident by the backlight 15 from the back surface side of the TFT substrate 11 on which the light shielding portion 4 is formed in this manner, the incident light is shielded, and as shown in FIG. Appears, so that the bright spot defect can be corrected.

As a result, in the liquid crystal display device 1 including the liquid crystal display panel 14 in which a defective pixel is detected as a bright spot, it is possible to correct the bright spot defect.

According to the present embodiment described above, the following effects can be obtained.

(4) In the present embodiment, the through hole 2 is formed in a region corresponding to the bright spot defect portion 18 of the glass substrate 21, and the foreign matter 16 is crushed through the through hole 2. Accordingly, even when a large foreign matter 16 having a diameter R larger than the thickness T of the liquid crystal layer 13 is present in the liquid crystal layer 13, the foreign matter 16 is crushed, so that the change in cell gap caused by the foreign matter 16 is changed. Is eliminated, and the cell gap can be made uniform in the liquid crystal layer 13. Therefore, in the liquid crystal display device 1 including the liquid crystal display panel 14 in which a defective pixel due to the large foreign matter 16 is detected as a bright spot, the bright spot defect can be reliably corrected. As a result, the liquid crystal display device 1 including the liquid crystal display panel 14 in which defective pixels are detected as bright spots can be regenerated without being discarded, and the yield of the liquid crystal display device 1 can be improved. become.

(5) In the present embodiment, the foreign material 16 is crushed by the drill stick 27. Accordingly, the foreign matter 16 present in the liquid crystal layer 13 can be reliably crushed.

Note that the above embodiment may be modified as follows.

The size of the liquid crystal display panel to which the present invention is applied is not particularly limited, and the present invention is not limited to a liquid crystal display device including a medium-to-small liquid crystal display panel in which defective pixels are detected as bright spots, or defective. The present invention can be applied to a liquid crystal display device including a large liquid crystal display panel in which pixels are detected as bright spots.

Needless to say, the present invention can also be applied to a liquid crystal display device using switching elements other than TFT elements.

Examples of utilization of the present invention include a manufacturing method of a liquid crystal display device in which a pair of substrates are overlapped at a predetermined interval and a liquid crystal layer is sealed in a gap between the pair of substrates, and a liquid crystal display device manufactured by the method. It is done.

DESCRIPTION OF SYMBOLS 1 Liquid crystal display device 2 Through-hole 3 Resin filling part 4 Light-shielding part 7 Carbide drill 11 TFT substrate (1st board | substrate)
12 CF substrate (second substrate)
DESCRIPTION OF SYMBOLS 13 Liquid crystal layer 14 Liquid crystal display panel 16 Foreign material 18 Bright spot defect part 21 Glass substrate 26 Stick-shaped suction machine 27 Drill stick T Thickness of liquid crystal layer R Diameter of foreign material

Claims (7)

A first substrate having a glass substrate provided on the display light incident side and a second substrate provided on the display light emitting side so as to face the first substrate through a liquid crystal layer. A step of preparing a liquid crystal display panel having a bright spot defect caused by a foreign substance present in the liquid crystal layer;
Forming a through hole in a region corresponding to the bright spot defect portion of the glass substrate;
Removing the foreign matter through the through hole;
And filling the resin into the through hole to form a resin filling portion. A method for manufacturing a liquid crystal display device, comprising: The method for manufacturing a liquid crystal display device according to claim 1, wherein, in the step of removing the foreign matter, the foreign matter is removed by sucking the foreign matter and extracting the foreign matter from the liquid crystal layer. 3. The method for manufacturing a liquid crystal display device according to claim 1, wherein the resin is a transparent resin. 4. The method of manufacturing a liquid crystal display device according to claim 3, wherein the transparent resin is a polycarbonate resin. A first substrate having a glass substrate provided on the display light incident side and a second substrate provided on the display light emitting side so as to face the first substrate through a liquid crystal layer. A step of preparing a liquid crystal display panel having a bright spot defect caused by a foreign substance present in the liquid crystal layer;
Forming a through hole in a region corresponding to the bright spot defect portion of the glass substrate;
Crushing the foreign matter through the through hole;
And a step of filling the through hole with a light shielding material to form a light shielding portion. 6. The method of manufacturing a liquid crystal display device according to claim 5, wherein, in the step of crushing the foreign matter, the foreign matter is crushed by a drill stick. A liquid crystal display device manufactured by the manufacturing method according to any one of claims 1 to 6.

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