JP2675199B2 - Display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a simple matrix display device having spacers that do not affect display.

[0002]

2. Description of the Related Art Conventionally, in a small-sized display device using a display medium such as liquid crystal, in order to keep the thickness of a liquid crystal layer between two substrates constituting the display device constant, the peripheral portion between the two substrates is kept constant. A spacer such as glass fiber is mixed in the sealant sandwiched between the spacers. When the spacer is mixed with the sealant, the display screen is not affected by the spacer. However, in a display device having a large screen of 3 inches or more, since the thickness of the liquid crystal layer is not constant, spacers are also mixed in the liquid crystal layer in the display portion.

FIG. 5 shows a cross-sectional view of a conventional simple matrix display device using spacers, and FIG. 6 shows a plan view of one substrate constituting the display device. This display device has a pair of insulating substrates 1 and 10 as shown in FIG.
Above the display electrodes 15 in parallel, as shown in FIG.
Are formed. A large number of display electrodes 16 are formed on a counter substrate 10 facing the substrate 1 in a direction perpendicular to the display electrodes 15. Further, alignment films 27 are formed on the substrates 1 and 10, respectively, and a liquid crystal layer 8 is enclosed between the substrates 1 and 10. Display electrodes 15 and 16
The intersection is the picture element. Also in this display device, spacers 17 are sandwiched in order to keep the layer thickness of the liquid crystal layer 8 between the substrates 1 and 10 constant.

[0004]

The display device shown in FIG. 5 is usually white or transparent. When a white or transparent spacer is used, there is a problem that when displaying black, the spacer portion becomes white, and the alignment ratio of liquid crystal molecules in the vicinity thereof is disturbed, so that the contrast ratio is greatly reduced. The use of such white or transparent spacers has a very serious problem since it has a bad influence on display quality.

In order to solve such a problem, it is considered to use a black spacer. However, since the hardness of the black spacer is not sufficiently high, there is a problem that the thickness of the liquid crystal layer cannot be kept uniform with high accuracy over a long period of time. Moreover, the problem caused by the disorder of the alignment of the liquid crystal molecules due to the use of the spacer remains unsolved.

An object of the present invention is to provide a simple matrix display device having a spacer which does not adversely affect the display and has high reliability.

[0007]

A simple matrix display device of the present invention includes a pair of insulating substrates, display electrodes formed on the substrates in directions intersecting with each other, and enclosed between the pair of substrates. A simple matrix display device having a display medium and a spacer for keeping a distance between the pair of substrates constant, wherein a conductive film is formed on at least one of the pair of substrates, and the conductive film is formed on the conductive film. The spacers are formed by the electrodeposition method, whereby the above object is achieved.

[0008]

In the simple matrix display device of the present invention, the conductive film is formed in the portion which does not contribute to the display, and the spacer is formed on the conductive film. Therefore, the image quality does not deteriorate due to the presence of the spacer. Since the spacer is formed by the electrodeposition method, it is formed in close contact with the conductive film. Therefore, the spacer does not peel off. Further, since the spacer having a uniform layer thickness is formed by the electrodeposition method, the uniformity of the layer thickness of the display medium can be enhanced.

[0009]

Embodiments of the present invention will be described below.

(Embodiment 1) FIG. 1 shows a sectional view of an embodiment of a simple matrix display device of the present invention, and FIG. 2 shows a plan view of one substrate constituting the display device. As shown in FIG. 1, this display device has a pair of insulating substrates 1 and 10, and an insulating film 20 is provided on the substrate 1.
Are formed on the entire surface, and a large number of display electrodes 15 which are parallel to each other are formed on the insulating film 20, as shown in FIG.

Electrodeposition electrodes 19 are formed on the substrate 1 between the display electrodes 15, as shown in FIG. As shown in FIG. 1, the spacer 18 is formed on the electrodeposition electrode 19 by the electrodeposition method. The spacer 18 is covered with the insulating film 20 and the alignment film 27 described above. A large number of display electrodes 16 are formed on a counter substrate 10 facing the substrate 1 in a direction perpendicular to the display electrodes 15. Further, alignment films 27 are formed on the substrates 1 and 10, respectively, and a liquid crystal layer 8 is enclosed between the substrates 1 and 10. The intersection of the display electrodes 15 and 16 becomes a picture element.

The spacer 18 does not have to be formed on the entire portion between the display electrodes 15, and the thickness of the liquid crystal layer 8 can be made constant in consideration of the size of the display device, the liquid crystal injection conditions, and the like. The spacers 18 having a small number and width may be formed.

The cell structure in this embodiment is shown in FIG.
In this embodiment, a compensation cell (not shown) is provided in addition to the driving cell of FIG. In FIG. 4, the solid line o indicates the polarization axis direction of the upper polarizing plate, and the arrows q and s respectively indicate the rubbing direction of the alignment film on the upper substrate of the driving cell (lower cell) and the compensation cell (upper cell). The direction of the rubbing treatment of the alignment film on the upper substrate of FIG. The broken line p indicates the polarization axis direction of the lower polarizing plate, and the arrows r and t indicate the rubbing direction of the alignment film on the lower substrate of the driving cell (lower cell) and the compensation cell (upper cell), respectively. The rubbing direction of the alignment film on the side substrate is shown. As shown in FIG. 4, the liquid crystal layer 8
The twist angle of the liquid crystal molecules therein is 240 degrees, and the display device of this embodiment is in the normally black mode.

Table 1 shows the display characteristics of the simple matrix display device of this embodiment. For comparison, Comparative Example 1 shows the display characteristics when the conventional display device shown in FIG. 5 is provided with a compensation cell.

[0015]

[Table 1]

Also in this embodiment, since the presence of the spacer 18 does not affect the display, a high contrast ratio can be obtained, and when applied to a color display device, the color purity becomes high and the image quality is improved. Further, since the layer thickness of each spacer 18 is also constant, the liquid crystal layer 8 having a uniform layer thickness over the entire display device is obtained. Also different liquid crystal materials,
It has been confirmed that similar effects can be obtained even when different cell configurations are adopted.

(Embodiment 2) FIG. 3 shows a sectional view of another embodiment of the simple matrix display device of the present invention. The plan view of one of the substrates constituting this display device is the same as FIG. 2 described above. As shown in FIG. 3, this display device has a pair of insulating substrates 1 and 10, and a large number of display electrodes 15 parallel to each other are formed on the substrate 1. An insulating film 20 is formed on the entire surface of the display electrode 15.

Electrodeposited electrodes 19 are formed on the insulating film 20 between the display electrodes 15, as shown in FIG. As shown in FIG. 3, the spacer 18 is formed on the electrodeposition electrode 19 by the electrodeposition method. The spacer 18 is covered with the alignment film 27. A large number of display electrodes 16 are formed on a counter substrate 10 facing the substrate 1 in a direction perpendicular to the display electrodes 15. Further, alignment films 27 are formed on the substrates 1 and 10, respectively, and a liquid crystal layer 8 is enclosed between the substrates 1 and 10. Display electrode 15
The intersections of 16 and 16 are the picture elements.

As in the first embodiment, the spacers 18 do not have to be formed on all the portions between the display electrodes 15,
In consideration of the size of the display device, the liquid crystal injection conditions, etc., the spacers 18 may be formed in a number and width as small as possible so that the layer thickness of the liquid crystal layer 8 can be kept constant.

The display device of this embodiment is in the normally black mode and has the cell structure shown in FIG. Also in this embodiment, a compensation cell (not shown) is provided in addition to the driving cell shown in FIG.

Table 2 shows the display characteristics of the simple matrix display device of this embodiment. For comparison, Comparative Example 1 shows the display characteristics when the conventional display device shown in FIG. 5 is provided with a compensation cell.

[0022]

[Table 2]

Also in this embodiment, since the presence of the spacer 18 does not affect the display, a high contrast ratio can be obtained, and when applied to a color display device, the color purity is increased and the image quality is improved. Further, since the layer thickness of each spacer 18 is also constant, the liquid crystal layer 8 having a uniform layer thickness over the entire display device is obtained. Also different liquid crystal materials,
It has been confirmed that similar effects can be obtained even when different cell configurations are adopted.

Although the transmissive display device has been described in the first and second embodiments, it has been confirmed that the same effect can be obtained in the case of the reflective display device. Further, the same examination was conducted in the case where the layer thickness of the spacer by the electrodeposition method was changed to 1 to 10 μm, but it was confirmed that the same effects as those shown in Table 1 and Table 2 were obtained.

[0025]

Since the simple matrix display device of the present invention has the spacer formed by the electrodeposition method in the portion which does not contribute to the display, the contrast ratio is lowered and the alignment of the liquid crystal molecules is disturbed by the spacer. Does not happen. Moreover, since the layer thickness of each spacer is constant, the layer thickness of the liquid crystal layer is constant over the entire display device. Therefore, according to the present invention,
A simple matrix display device having high image quality can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an embodiment of a simple matrix display device of the present invention.

FIG. 2 is a plan view of one substrate which constitutes the simple matrix display device of FIG.

FIG. 3 is a cross-sectional view of another embodiment of the simple matrix display device of the present invention.

4 is a diagram showing a cell configuration of the simple matrix display device shown in FIGS. 1 and 3. FIG.

FIG. 5 is a cross-sectional view of a simple matrix display device having a conventional spacer.

FIG. 6 is a plan view of one substrate included in the display device of FIG. 5;

[Explanation of symbols]

 1, 10 Insulating substrate 8 Liquid crystal layer 15, 16 Display electrode 18 Spacer 19 Electrodeposition electrode 27 Alignment film

Claims (1)

(57) [Claims] 1. A pair of insulating substrates, display electrodes formed on the respective substrates in directions intersecting with each other, a display medium enclosed between the pair of substrates, and a distance between the pair of substrates. A simple matrix display device having a spacer for keeping constant, wherein a conductive film is formed on at least one of the pair of substrates, and the spacer is formed on the conductive film by an electrodeposition method. Display device.