JPH0876132A - Liquid crystal display manufacturing method - Google Patents

Abstract

(57) [Summary] (Correction) [Object] To provide a method for manufacturing a liquid crystal display device, which can prevent a decrease in contrast due to a spacer for securing a gap between substrates. In a method of manufacturing a liquid crystal display device in which a liquid crystal material is sandwiched between two substrates having electrodes, spacers 16 for spraying spacers 16 for maintaining a gap between the two substrates are dispersed. The first electrode 12 provided in a region where the spacer 16 is to be arranged on the substrate 10 on the side on which the spacer 16 is sprayed, which is positively or negatively charged.
To the spacer 16 by applying an electric potential of a different polarity to that of the spacer 16.
A potential having the same polarity as that of the spacer 16 is applied to the second electrode 14 provided in a region where the spacer is unnecessary on the substrate 10 on the side where the spacers are scattered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a liquid crystal display device, and more particularly to a method of spraying spacers.

[0002]

2. Description of the Related Art In a liquid crystal display device, a liquid crystal material is sandwiched between two glass substrates, an electric field is applied between the two glass substrates to orient the liquid crystal, and the optical properties of the liquid crystal are changed. It functions as a display device. When the liquid crystal is sandwiched between the glass substrates, it is necessary to secure a gap for sandwiching the liquid crystal between the two glass substrates.
Therefore, usually, a gap is secured by sandwiching spherical or columnar spacers made of silica, alumina, resin, or the like, which are previously dispersed on one glass substrate, between the glass substrates.

When the spacers are dispersed on the glass substrate, if the dispersion density of the spacers is not uniform in the glass substrate surface, unevenness in the gaps between the glass substrates will occur, causing unevenness in color. A spraying method called a dry method or a wet method is used, which can uniformly spray the in-plane. However, in these methods, the spacers can be evenly dispersed on the glass substrate to suppress the gap unevenness, but naturally, the spacers are also dispersed in the openings of the pixels. When the spacers are scattered in the openings of the pixels in this manner, when the liquid crystal is sandwiched between the glass substrates to form the liquid crystal display device, the liquid crystal does not exist at the place where the spacer is present. Therefore, for example, in a conventional TN type normally black liquid crystal display device, light is transmitted even in an off state where a spacer is present.
As a result, the contrast is reduced. In addition, when a colored spacer is used to prevent the transmission of light, or in a TN type normally white liquid crystal display device, there is a phenomenon that light circulates around the spacer because the alignment of the liquid crystal around the spacer is disturbed. However, there is a problem that a part of light is transmitted and the contrast is lowered.

As a method for preventing the deterioration of the contrast, there are disclosed in Japanese Unexamined Patent Publication Nos. 5-53121 and 4-2.
A method of manufacturing a liquid crystal display device described in Japanese Patent No. 04417 has been proposed. In the method for manufacturing a liquid crystal display device described in Japanese Patent Laid-Open No. 5-53121, the spacers 16 to be scattered are charged in advance, and the electrodes 32 are provided in the regions 36 on the glass substrate 10 where the spacers are to be scattered. This is a method in which a potential having a polarity opposite to that is applied and the spacers 16 are attracted to the outside of the openings 30 of the pixels to selectively disperse the spacers 16 (FIG. 6A).

Further, in the method of manufacturing a liquid crystal display device described in JP-A-4-204417, the spacers 16 to be scattered are charged in advance and the spacers 1 on the glass substrate 10 are also charged.
Electrodes 32 are provided in regions 34 where 6 is not desired to be dispersed, a potential having the same polarity as the spacer 16 is applied to the electrodes 32, and the repulsion of Coulomb force is utilized to make the spacers 1 in the openings 30 of the pixels.
This is a method to prevent 6 from being scattered (Fig. 6).
(B)).

[0006]

However, in the method of manufacturing a liquid crystal display device disclosed in Japanese Patent Application Laid-Open No. 5-53121, spacers 16 are formed on the electrodes 32 as shown in FIG. 6 (a).
Area 3 where you want to collect spacers but do not want to spray spacers 16
There is a problem that it is difficult to completely remove the spacer from No. 4.

Further, in the method of manufacturing a liquid crystal display device disclosed in Japanese Patent Laid-Open No. 4-204417, the spacers 16 can be removed from the regions 34 where the spacers are not desired to be dispersed, as shown in FIG. Since the force for attracting the spacer 16 does not work in the desired region 36, there is a problem in that the spacer 16 protrudes into the region 34 in which the spacer is not desired to be scattered in some cases.

An object of the present invention is to provide a method of manufacturing a liquid crystal display device capable of preventing a decrease in contrast caused by a spacer for securing a gap between substrates.

[0009]

The above object is to provide a spacer for holding a gap between two substrates in a method of manufacturing a liquid crystal display device in which a liquid crystal material is sandwiched between two substrates having electrodes. When the spacer is sprayed, the spacer to be sprayed is charged either positively or negatively, and the first electrode provided in the region where the spacer is to be arranged on the substrate on the side where the spacer is sprayed is different from the spacer. Applying a potential of a pole, on the substrate on the side of spraying the spacer,
In the second electrode provided in the region where the spacer is unnecessary,
This is achieved by a method for manufacturing a liquid crystal display device, which is characterized in that a potential having the same polarity as that of the spacer is applied.

Further, in the above-described method of manufacturing a liquid crystal display device, the substrate on the side where the spacers are scattered faces a TFT substrate provided with a plurality of thin film transistors for controlling a voltage applied to a plurality of pixel electrodes. It is preferable that the second electrode is provided on a surface of the counter substrate facing the pixel electrode.

Further, in the above method for manufacturing a liquid crystal display device, the substrate on which the spacers are scattered is a TFT substrate provided with a plurality of thin film transistors for controlling a voltage applied to a plurality of pixel electrodes, It is preferable that the first electrode is the pixel electrode corresponding to any one of red, green, and blue pixels, and the second electrode is the pixel electrode other than the first electrode.

Further, in the above method of manufacturing a liquid crystal display device, it is desirable that the spacer has an adhesive material for fixing the spacer to the substrate. In addition, in a method of manufacturing a liquid crystal display device in which a liquid crystal material is sandwiched between two substrates having electrodes, when spraying spacers for holding a gap between the two substrates, the spacers to be sprayed are aligned. Voltage on a gate bus line for controlling gates of the plurality of thin film transistors on a TFT substrate provided with a plurality of thin film transistors for controlling a voltage applied to a plurality of pixel electrodes of the two substrates. To turn on the thin film transistor, apply a positive voltage to the drain bus line connected to the drains of the plurality of thin film transistors to positively charge the pixel electrodes, and shut off the voltage of the gate bus line. After turning off the thin film transistor, the spacer is attached to the TFT.
It is achieved by a method for manufacturing a liquid crystal display device, which is characterized in that it is sprayed on a substrate.

[0013]

According to the present invention, of the two electrodes provided on the substrate, one electrode is positively or negatively charged while a positive potential is applied to the other electrode. Since the spacers are dispersed, it is possible to selectively disperse the spacers on one of the electrodes.

Further, when the charged spacers are scattered on the TFT substrate, if the potential of the pixel electrode is set to a potential different from that of the spacer, the spacer is not scattered on the pixel electrode and the liquid crystal by the spacer is used. It is possible to prevent a decrease in contrast of the display device. Further, by selectively distributing spacers on pixel electrodes corresponding to pixels of a specific color, in a multi-gap liquid crystal display device in which a gap is different between pixels of different colors, spacers that do not function as spacers even if dispersed are formed. Can be eliminated. As a result, the consumption amount of the spacer can be reduced.

If spacers with an adhesive that can be fixed to the substrate by a heat treatment in a later step are used, the spacers that are selectively scattered can be prevented from protruding into the openings of the pixels when the liquid crystal display device is assembled. be able to.
In addition, since the positively charged spacers are dispersed in the state where the positive potential is applied to the drain bus line and the pixel electrode and the negative potential is applied to the gate bus line, the spacers should be selectively dispersed on the gate bus line. You can As a result, it is possible to prevent the contrast of the liquid crystal display device from being lowered by the spacer.

[0016]

EXAMPLE A method of manufacturing a liquid crystal display device according to a first example of the present invention will be described with reference to FIGS. FIG. 1 is a schematic view showing electrodes of a counter substrate used in the first embodiment of the present invention, FIG. 2 is a diagram for explaining the interaction between the spacers and the electrodes, and FIG. 3 is a graph showing the interaction between the spacers and the electrodes. It is a figure which shows the position of the spacer.

In the method of manufacturing the liquid crystal display device according to the present embodiment, two electrodes are provided on the counter substrate on the color filter side, and voltages of different polarities are applied to the electrodes, so that one electrode can be spacers with good selectivity. It is characterized by spraying. That is, as shown in FIG. 1A, the first electrode 12 is formed on the counter substrate 10 on the color filter side.
And the second electrode 14 is formed in a comb shape. The first electrode 12 has a thickness of about 20 to fit in the light shielding portion 28 of the light shielding film (FIG. 1B) on the color filter side.
It is formed with a width of 30 μm. The second electrode 14 is arranged at a position corresponding to the opening 30 of the pixel and has a width of about 80 to
It is formed with a thickness of 90 μm.

Spacers 16 were dispersed on the counter substrate 10 by the following method. First, -10 is applied to the first electrode.
A negative potential of V was applied by the DC power source 38, and a positive potential of +10 V was applied by the DC power source 40 to the second electrode. Next, the positively charged spacers 16 are formed at a density of 300 pieces / m.
It was sprayed at a rate of m ² . The spacers were sprayed using a dry spacer spraying device manufactured by Nisshin Seifun Co., Ltd., and "Micropearl Spacer (φ5.5μ) manufactured by Sekisui Fine Chemical Co., Ltd.
m) ”was charged to a positive potential by passing it through a metal tube and then sprayed.

The spacers 16 thus distributed
As shown in FIG. 2, when it reaches the counter substrate 10, it receives Coulomb force from the first electrode 12 and the second electrode 14. That is, the first electrode 12 and the spacer 1 applied negatively
An attractive force is exerted on 6 and a repulsive force is exerted between the positively applied second electrode and the spacer 16. As a result, the spacer 16 can be selectively arranged on the first electrode 12 as shown in FIG.

In the method of manufacturing a liquid crystal display device described in Japanese Patent Application Laid-Open No. 4-204417, the force for attracting the spacer 16 does not work in the region where the spacer 16 is desired to be arranged. However, in this embodiment, the spacers 16 are removed from the regions where the spacers 16 are not desired to be scattered, and the spacers 16 are attracted to the regions where the spacers 16 are desired to be dispersed. Things are gone.

As described above, according to this embodiment, the counter substrate 10 is provided with the two electrodes, and the first electrode 12 is used as the spacer 1.
Since the potential of the second electrode 14 is the same as that of the spacer 16, and the potential of the second electrode 14 is the same as that of the spacer 16, the dispersed spacers 16 can be dispersed on the first electrode 12 with good selectivity. As a result, the spacer 16 does not exist in the opening 30 of the pixel, so that it is possible to prevent the contrast of the liquid crystal display device from being lowered.

In this embodiment, "Micropearl spacer" manufactured by Sekisui Fine Chemical Co., Ltd. was used as the spacer 16. However, since the scattered spacers 16 cannot be fixed to the substrate, the apertures of the pixels are assembled when the liquid crystal display device is assembled. Part 30
There is a risk of protruding. Therefore, the spacer 16 has
It is desirable to use a spacer with an adhesive that can be fixed to the substrate 10 by heat treatment in a later step. For this, for example, "Haya beads" manufactured by Hayakawa Rubber Co., Ltd. may be used. In this case, since the surface state is different from that of the "micropearl spacer", the polarity charged during spraying may change. In this case, the polarity of the voltage applied to the first electrode and the second electrode may be changed. Just replace them.

Next, a method of manufacturing the liquid crystal display device according to the second embodiment of the present invention will be described with reference to FIG. FIG. 4 is a diagram illustrating a method of manufacturing a liquid crystal display device according to an embodiment of the present invention. As shown in FIG. 4A, the gate bus lines 18 arranged in parallel, the drain bus lines 20 arranged in a direction orthogonal to the gate bus lines 18, and the intersections of the gate bus lines 18 and the drain bus lines 20. The spacers 16 are dispersed on the TFT substrate having the pixel electrode 24 connected to the source electrode of the thin film transistor 22 provided in.

At this time, in the method of manufacturing the liquid crystal display device according to the present embodiment, the spacers charged to a positive potential by setting the potential of the gate bus line to a positive potential and the potentials of the drain bus line and the pixel electrode to a negative potential. Is selectively sprayed only on the gate bus line. That is, as shown in FIG. 4A, a positive potential is applied to the gate bus line 18 to turn it on, and a potential of +10 V is applied to the drain bus line 20. As a result, the pixel electrode 24 has a positive potential.
Next, when the gate bus line 18 is turned off (FIG. 4 (b)), the TFT circuit is turned off, which causes a negative offset voltage of several volts on the gate bus line 18.

Therefore, when the spacers 16 which are positively charged in this state are scattered on the substrate by the same method as that of the first embodiment, the drain bus line 20 and the pixel electrode 24 having a positive potential are provided between the spacer and the spacer. A repulsive force acts on the gate bus line 18 and the spacer 16 having a negative potential. As a result, the spacer 16 becomes the gate bus line 1
8 can be selectively placed (FIG. 4 (c)).

As described above, according to this embodiment, since the gate bus line 18 is set to the negative potential and the drain bus line 20 and the pixel electrode 34 are set to the positive potential, the spacers 16 charged to the positive potential are scattered. The sprayed spacers 16 can be selectively sprayed on the gate bus lines 18. Further, as a result, the spacer 16 does not exist in the opening 30 of the pixel, so that it is possible to prevent the contrast of the liquid crystal display device from being lowered.

Next, a method of manufacturing a liquid crystal display device according to the third embodiment of the present invention will be described with reference to FIG. FIG. 5 is a diagram for explaining the method of manufacturing the liquid crystal display device according to this embodiment. When spraying the spacers on the glass substrate, it is desirable to spray them evenly in the plane. However, in a multi-gap type liquid crystal display device or the like in which the cell gaps of pixels of three colors are different, the gap is determined by the spacer in the region where the gap between the glass substrates is the smallest, and the spacers scattered in other regions are spacers. The function as is not fulfilled. In this embodiment, a liquid crystal display device which can be used for a multi-gap type liquid crystal display device and the like and which can reduce the consumption amount of spacers will be shown.

As shown in FIG. 5A, the gate bus lines 18 are arranged in parallel, the drain bus lines 20 are arranged in a direction orthogonal to the gate bus lines 18, the gate bus lines 18 and the drain bus lines. The spacer 1 is provided on the TFT substrate having the pixel electrode 24 connected to the source electrode of the thin film transistor 22 provided at the intersection of 20.
Disperse 6.

At this time, in the method of manufacturing the liquid crystal display device according to the present embodiment, the spacers are selectively arranged on the predetermined pixel electrodes. That is, the color liquid crystal display device includes the pixel electrodes 24R, 24G, and 24B corresponding to the three color pixels of red (R), green (G), and blue (B), but in the present embodiment, Spacers are selectively arranged on the pixel electrodes corresponding to any of the three colors.

The method of spraying the spacers will be described below.
First, a negative potential is applied to the drain bus line 20 corresponding to the pixel electrode 24 on which the spacer 16 is desired to be dispersed. For example, if spacers are to be scattered on the pixel electrode 22R corresponding to red, a negative potential of -20V is applied to the drain bus lines 20a, 20d, ... Corresponding to the pixel electrode 24R. On the other hand, a positive potential is applied to the drain bus line 20 corresponding to the pixel electrode 24 where the spacer 16 is not desired to be dispersed. For example, a positive potential of +20 V is applied to the drain bus lines 20b, 20c, ... Corresponding to the pixel electrodes 24G, 24B. As a result, a negative potential is applied to the pixel electrode 22R and a positive potential is applied to the pixel electrodes 24G and 24B.

In this state, if the positively charged spacers 16 are scattered on the TFT substrate 26, a repulsive force is exerted between the pixel electrodes 24G and 24B having a positive potential and the spacers, and a pixel electrode 24R having a negative potential. An attractive force acts on the spacer 16. Thereby, the spacer 16 can be selectively arranged on the pixel electrode 24R (FIG. 5B). As described above, according to the present embodiment, the spacer 16 can be selectively arranged on the predetermined pixel electrode 34, so that even in a multi-gap type liquid crystal display device in which the cell gaps of the pixels of the three colors are different from each other. The spacer 16 can be selectively arranged on the pixel electrode 34 having the narrowest gap. As a result, the scattered spacers 16 can effectively function and the consumption amount of the spacers 16 can be reduced.

The pixel electrodes 22 on which the spacers 16 are scattered have a lowered contrast as described above,
It is desirable that the spacers 16 are scattered on the pixel electrodes that have little influence when light leakage occurs.

[0033]

As described above, according to the present invention, of the two electrodes provided on the substrate, one electrode is applied with a positive potential and the other electrode is applied with a negative potential, Since the positively or negatively charged spacers are sprayed, the spacers can be sprayed to either one of the electrodes with good selectivity.

Further, when the charged spacers are scattered on the TFT substrate, if the potential of the pixel electrode is set to a potential different from that of the spacer, the spacer is not scattered on the pixel electrode, and the liquid crystal by the spacer is generated. It is possible to prevent a decrease in contrast of the display device. Further, by selectively distributing spacers on pixel electrodes corresponding to pixels of a specific color, in a multi-gap liquid crystal display device in which a gap is different between pixels of different colors, spacers that do not function as spacers even if dispersed are formed. Can be eliminated. As a result, the consumption amount of the spacer can be reduced.

If spacers with an adhesive that can be fixed to the substrate by heat treatment in a later step are used, the spacers that are selectively scattered can be prevented from protruding into the openings of the pixels when the liquid crystal display device is assembled. be able to.
In addition, since the positively charged spacers are dispersed in the state where the positive potential is applied to the drain bus line and the pixel electrode and the negative potential is applied to the gate bus line, the spacers should be selectively dispersed on the gate bus line. You can As a result, it is possible to prevent the contrast of the liquid crystal display device from being lowered by the spacer.

[Brief description of drawings]

FIG. 1 is a schematic view showing electrodes of a counter substrate used in a first embodiment of the present invention.

FIG. 2 is a diagram for explaining the interaction between the dispersed spacers and electrodes.

FIG. 3 is a diagram showing positions of spacers scattered on a counter substrate.

FIG. 4 is a diagram illustrating a method of manufacturing the liquid crystal display device according to the second embodiment of the present invention.

FIG. 5 is a diagram illustrating a method of manufacturing the liquid crystal display device according to the third embodiment of the present invention.

FIG. 6 is a diagram illustrating a method of manufacturing a conventional liquid crystal display device.

[Explanation of symbols]

 10 ... Counter substrate 12 ... 1st electrode 14 ... 2nd electrode 16 ... Spacer 18 ... Gate bus line 20 ... Drain bus line 22 ... Thin film transistor 24 ... Pixel electrode 28 ... Shading part 30 ... Pixel opening 32 ... Electrode 34 Areas where spacers are not desired to be dispersed 36 Areas where spacers are not desired to be dispersed 38 ... DC power supply 40 ... DC power supply

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoji Suzuki 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Fujitsu Limited

Claims (5)

[Claims] 1. A method of manufacturing a liquid crystal display device in which a liquid crystal material is sandwiched between two substrates having electrodes, wherein a spacer for holding a gap between the two substrates is dispersed when the spacers are dispersed. The spacer is charged to either positive or negative, and a potential of a different polarity from that of the spacer is applied to a first electrode provided in a region where the spacer is to be arranged on the substrate on the side where the spacer is scattered, A method of manufacturing a liquid crystal display device, wherein a potential having the same polarity as that of the spacer is applied to a second electrode provided in a region where the spacer is unnecessary on the substrate on the side where the spacer is scattered. 2. The method of manufacturing a liquid crystal display device according to claim 1, wherein the substrate on the side on which the spacers are dispersed is provided with a plurality of thin film transistors for controlling a voltage applied to a plurality of pixel electrodes. A method of manufacturing a liquid crystal display device, wherein the second electrode is provided at a position facing the pixel electrode on the counter substrate. 3. The method of manufacturing a liquid crystal display device according to claim 1, wherein the substrate on the side on which the spacers are dispersed is provided with a plurality of thin film transistors for controlling a voltage applied to a plurality of pixel electrodes. Wherein the first electrode is the pixel electrode corresponding to any one of red, green, and blue, and the second electrode is the pixel electrode other than the first electrode. Liquid crystal display device. 4. The method of manufacturing a liquid crystal display device according to claim 1, wherein the spacer has an adhesive material for fixing the spacer to the substrate. . 5. A method of manufacturing a liquid crystal display device in which a liquid crystal material is sandwiched between two substrates having electrodes, wherein a spacer for holding a gap between the two substrates is dispersed when the spacers are dispersed. The spacer is positively charged, and the plurality of thin film transistors for controlling the voltage applied to the plurality of pixel electrodes of the two substrates are provided in the T
On the FT substrate, a voltage is applied to a gate bus line that controls the gates of the plurality of thin film transistors to turn on the thin film transistors, and a positive voltage is applied to a drain bus line connected to the drains of the plurality of thin film transistors to apply a plurality of voltages. A method of manufacturing a liquid crystal display device, wherein the pixel electrode is positively charged, the voltage of the gate bus line is cut off to turn off the thin film transistor, and then the spacers are dispersed on the TFT substrate.