JPH0980414A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of display defect by forming an electrically conductive light shielding film into divided pattern, thereby reducing the voltage drop of a counter electrode even through the transparent electrode on a top coat and the light shielding film are into continuity. SOLUTION: A matrix shaped light shielding film 6 is formed by a photo-lithography by depositong chromium on the transparent insulating substrate made of glass. The light shielding film 6 is formed corresponding to gate lines and drain lines of a TFT array substrate when it is combined with the substrate. At this time, the film 6 is formed into such patterns that it is finely divided. Such patterns are easily formed by changing mask patterns at the time of forming the light sheilding film 6 by the photo-lithography as the method forming the film and it is desirable that intervals among divisions of the light shielding film 6 are the order of about 5μm∼10μm. Consequently, even though the counter electrode and the light shielding film 6 are brought into conduction by the pinhole of the top coat, etc., since voltage is leaked only through the part in contact with the counter electrode, the voltage drop is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device provided with a conductive light shielding film.

[0002]

2. Description of the Related Art Generally, a conventional liquid crystal display device has a structure in which a liquid crystal is sandwiched between two electrode substrates, one of which is a light-shielding film such as chrome on a transparent insulating substrate. Is formed, an insulating film is formed thereon, and a transparent electrode is further formed.

The conventional light-shielding film has an integral structure, and when the light-shielding film is formed as described above, it is electrically connected to the transparent electrode on the insulating film due to protrusions caused by the light-shielding film or pinholes in the insulating film. In this case, the voltage that should be applied to the transparent electrode leaks to the entire pattern of the lower light-shielding film, and the voltage of the transparent electrode drops.

[0004]

As described above,
In the structure in which the conductive light-shielding film is integrated, when it is brought into conduction with the transparent electrode, a voltage drop occurs in the transparent electrode, which adversely affects the display. The present invention has been made in view of the above problems, and an object thereof is to provide a liquid crystal display device in a good display state.

[0005]

According to the present invention, a conductive light-shielding film is formed in a predetermined pattern on a transparent insulating substrate, and an insulating film is formed on the transparent insulating substrate having the light-shielding film formed thereon.
A transparent electrode is formed on the insulating film, a first electrode substrate having an alignment film is formed on the transparent insulating substrate including the transparent electrode, and a transparent electrode is formed on the transparent insulating substrate. In a liquid crystal display device comprising a second electrode substrate having an alignment film formed on an insulating substrate, and a liquid crystal sandwiched between the first electrode substrate and the second electrode substrate, the predetermined pattern is: The liquid crystal display device is characterized in that the entire light shielding film is partially divided without conducting.

According to the present invention, the conductive light-shielding film is divided and formed so as not to be electrically connected to the entire pattern of the light-shielding film. For example, the transparent electrode on the insulating film and the light-shielding film are electrically connected by the pinhole of the insulating film. Even if it does, since it does not conduct to the light-shielding film in the part where there is no pinhole, it is possible to suppress the voltage drop of the transparent electrode with a small amount, and it is possible to eliminate the display defect.

[0007]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below with reference to the drawings. FIG. 1 shows the configuration of a liquid crystal display device according to an embodiment of the present invention. In this embodiment, a thin film transistor (hereinafter, referred to as TFT: Thin Film Transistor) is used.
is a liquid crystal display device of the active matrix type using (tor) as a switching element. First, as a counter substrate which is a first electrode substrate, a light-shielding film 6 made of, for example, chromium (Cr) and formed in a matrix on a transparent insulating substrate 5 made of glass, and surrounded by the light-shielding film 6. Red (R), green (G), and blue (B) color filters 7 respectively formed in the pixel regions, and the color filters 7 formed on the entire surface of the color filters 7 for protection, surface flattening, and insulation. The top coat 8 as a film and the ITO (Indium T) formed on the entire surface of the top coat 8.
counter electrode 9 which is a transparent electrode composed of in oxide)
And an alignment film 10 formed on the entire top surface.

The TFT array substrate, which is the second electrode substrate, is composed of a transparent insulating substrate 1 made of glass, a TFT 2 provided corresponding to each pixel region, and a transparent portion connected to a part of the TFT 2. The pixel electrode 3 which is an electrode, and the alignment film 4 formed on the entire uppermost layer are further formed.

Then, the TFT array substrate and the counter substrate face the formation surfaces of the pixel electrode 3 and the counter electrode 9 with each other through the sealant 11 and a spacer (not shown).
The liquid crystal 12 is sandwiched.

A polarizing plate 1 is provided on the outer surface of both electrode substrates.
3a and 13b are provided, and a backlight 14 for illumination is arranged on the TFT array substrate side.
The drive IC 15 is mounted on the array substrate to form the liquid crystal display device of this embodiment.

Among these, a method of manufacturing the counter substrate including the light shielding film 6 will be described in detail. First, about 1000 A of chromium is deposited on the transparent insulating substrate 5 made of glass, and the light-shielding film 6 in a matrix is formed by photolithography. Here, the light shielding film 6 is formed so as to correspond to the gate line and the drain line of the TFT array substrate when combined with the TFT array substrate.

At this time, the light-shielding film 6 is shaped so as to be finely divided as shown in FIG. 2 (a) or 2 (b). As a method, by changing the mask pattern when forming the light shielding film 6 by photolithography, the light shielding film 6 having the pattern of this embodiment can be easily formed.

Here, the dividing interval of the light shielding film 6 is about 5 μm.
About 10 μm is preferable. The wider the division interval is, the more surely the insulation is provided. However, if it is too wide, the light-shielding performance is deteriorated, resulting in a display with low contrast.

The material of the light-shielding film 6 is not limited to chromium,
There are various modes of conductive materials such as other metals, alloys, and metals having a laminated structure. Next, the area surrounded by the light-shielding film 6 formed in a matrix becomes each pixel area,
The red, green, and blue color filters 7 are formed in the respective pixel regions by a pigment dispersion method, for example, with a film thickness of 1.0 μm to 2.5 μm. In addition to the pigment dispersion method, a forming method such as a dyeing method, a printing method, and an electrodeposition method can be used.

Further, as a top coat 8 for protecting the color filter 7 on the entire surface, flattening the surface, and insulating the counter electrode 9 and the light-shielding film 6, an epoxy resin or the like is formed by a spinner to have a film thickness of about 1 μm to 2 μm. To form.

Next, a transparent electrode 9 made of ITO is formed on the entire surface by sputtering, for example, to have a film thickness of 1000A to 2000A. Finally, the alignment film 10 made of polyimide is formed on the entire surface.
To a film thickness of 800A to 900A by, for example, a spin coating method.
Then, the desired counter substrate is completed.

The dividing pattern of the light-shielding film 6 is not only the pattern shown in FIGS. 2 (a) and 2 (b) but also the pattern divided for each pixel as shown in FIG. Furthermore, as shown in FIG.
There is also a pattern in which each pixel is divided into three pixels as shown in (b).

It is needless to say that these figures are merely examples of division patterns, and that various modes other than this are conceivable. As for the division, if the division is fine, the damage of the leak can be reduced, but the light shielding effect is sacrificed because the number of portions where the light shielding film is cut increases. The design should be done with that in mind.

Further, in this embodiment, the light shielding film 6 is provided on the counter substrate side.
Although it is a liquid crystal display device in which is formed, it is also applicable to a liquid crystal display device in which a light shielding film is formed on the array substrate side. Further, not only the active matrix type liquid crystal display device but also the simple matrix type liquid crystal display device in which the electrodes formed on the two electrode substrates each have a stripe shape and are combined so as to be orthogonal to each other.

It is also applicable to a light-shielding film in which red, green and blue pixels are arranged in a delta. As described above, it is needless to say that the present embodiment can add many changes or modifications within the scope of the invention.

According to the configuration of this embodiment, for example, the light shielding film 6
Even if the counter electrode 9 and the light-shielding film 6 are brought into conduction due to a protrusion or a pinhole in the top coat 8 due to the formation of the above, voltage is applied only to the divided portion of the light-shielding film 6 in contact with the counter electrode 9. Can be prevented from leaking, and the voltage can be prevented from leaking to most other portions of the light shielding film 6, and the voltage drop of the counter electrode 3 can be greatly reduced. Therefore, it is possible to reduce display unevenness.

[0022]

According to the present invention, by forming the conductive light-shielding film 6 in a divided pattern, even if the transparent electrode 9 on the top coat 8 is electrically connected to the light-shielding film 6, the voltage drop of the counter electrode is prevented. It can be stopped with a small amount, and display defects can be eliminated.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing the structure of a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a plan view showing a pattern of a light shielding film according to an embodiment of the present invention.

FIG. 3 is a plan view showing a pattern in which a light shielding film according to an embodiment of the present invention is divided into pixels.

FIG. 4 is a plan view showing a pattern obtained by dividing a light shielding film into three pixels according to an embodiment of the present invention.

[Explanation of symbols]

 1, 5 ... Transparent insulating substrate 2 ... TFT 3 ... Pixel electrode 4, 10 Alignment film 6 ... Light-shielding film 7 ... Color filter 8 ... Top coat 9 ... Counter electrode 12 ... Liquid crystal

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Nobu Shin Nose, 1-9-9 Harara-cho, Fukaya-shi, Saitama Incorporated company Toshiba Fukaya Electronics Factory

Claims (9)

[Claims] 1. A conductive light-shielding film is formed in a predetermined pattern on a transparent insulating substrate, an insulating film is formed on the transparent insulating substrate on which the light-shielding film is formed, and a transparent electrode is formed on the insulating film. A first electrode substrate on which an alignment film is formed on the transparent insulating substrate including the transparent electrode, and a transparent electrode formed on the transparent insulating substrate, and the insulation on which the transparent electrode is formed. In a liquid crystal display device comprising a second electrode substrate having an alignment film formed on a flexible substrate, and a liquid crystal sandwiched between the first electrode substrate and the second electrode substrate, the predetermined pattern is A liquid crystal display device, wherein the entire light-shielding film is partially divided without electrical conduction. 2. The liquid crystal display device according to claim 1, wherein a pixel region is formed by the matrix light-shielding film having a row direction and a column direction, and the predetermined pattern is one pixel in each of the row direction and the column direction. A liquid crystal display device characterized by being divided by the length of a minute. 3. The liquid crystal display device according to claim 1, wherein the light-shielding film forms a pixel region, and the predetermined pattern is divided for each pixel. 4. The liquid crystal display device according to claim 1, wherein a pixel region is formed by the light shielding film, and the predetermined pattern is divided every three pixels. 5. The liquid crystal display device according to claim 1, 2, 3 or 4, wherein a color filter is provided on the first electrode substrate or the second electrode substrate. 6. The liquid crystal display device according to claim 1, 2, 3 or 4, wherein the first electrode substrate or the second electrode substrate is provided with a switching element for controlling a drive voltage of liquid crystal. Liquid crystal display device. 7. The liquid crystal display device according to claim 1, 2, 3 or 4, wherein the transparent electrodes of the first electrode substrate and the second electrode substrate are stripe-shaped, and the stripes are orthogonal to each other. A liquid crystal display device characterized in that the liquid crystal display device is arranged in a row. 8. The liquid crystal display device according to claim 1, 2, 3 or 4, wherein the light shielding film is made of chromium or an alloy containing chromium. 9. The liquid crystal display device according to claim 1, 2, 3 or 4, wherein the interval at which the light shielding film is divided is 5 μm to 10 μm.