KR20020028374A - method for fabricating In plain switching and the same - Google Patents

Abstract

PURPOSE: An IPS(In Plane Switching) LCD(Liquid Crystal Display) device and a method for fabricating the same are provided to employ a transparent material of conductive metal at a back side of an array panel for IPS LCD devices, to radiate static electricity locally generated in a lower panel to an external, so that a spot is not generated upon panel driving. CONSTITUTION: An upper substrate(A) in which a first back electrode that is a transparent conductive metal is formed on one part of a transparent first substrate. A lower substrate(B) in which a switching element, a pixel electrode and a common electrode are formed in one part of a transparent second substrate, and a second back electrode(155) that is a transparent conductive metal is formed in the other part of the transparent second substrate. A liquid crystal is interposed between the upper and lower substrates(A,B). An upper polarizer(131) is formed in an upper part of the first back electrode. A lower polarizer(135) is formed on a lower part of the second back electrode(155). And a light distribution device is formed in a lower part of the lower polarizer(135).

Description

Transverse electric field type liquid crystal display device and its manufacturing method {method for fabricating In plain switching and the same}

The present invention relates to a liquid crystal display device, and more particularly, to a structure and a manufacturing method of a transverse electric field type liquid crystal display device having a conductor for preventing static electricity on the rear surface of the lower substrate.

In general, a liquid crystal display device is formed by bonding an upper substrate and a lower substrate, and injecting a liquid crystal between the bonded upper substrate and the lower substrate.

A polarizer, a retardation film, and the like are attached to outer surfaces of the upper and lower substrates. By selectively configuring such a plurality of components, a liquid crystal display device having high brightness and contrast characteristics by changing a light propagation state or a refractive index is configured.

Liquid crystals used in recent years as a liquid crystal display generally adopt a twist nematic LC, and the twisted nematic liquid crystal has a property that the light transmittance in gradation display varies depending on the viewing angle. There is a limit.

The liquid crystal cell including the twisted nematic liquid crystal is symmetrically distributed in a wide range of light transmittance at the viewing angle in the left and right directions, but because the light transmittance is distributed asymmetrically in the up and down directions, the image is reversed in the up and down directions. There was a problem that a range occurs and the viewing angle is narrowed.

On the contrary, the transverse electric field mode (hereinafter referred to as "IPS mode") using a parallel electric field is contrast, gray inversion, compared to the conventional twisted nematic liquid crystal mode. There is an advantage that can improve the viewing angle characteristics such as color shift (color shift).

Hereinafter, a schematic configuration of an array substrate for a transverse electric field type liquid crystal display device will be described with reference to FIG. 1.

As shown, the array substrate is formed by crossing the gate wiring 13 and the data wiring 15 on the substrate. In particular, in the IPS mode, a pixel in which the gate wiring 13 and the data wiring 15 cross each other is defined. The pixel electrode 17 and the common electrode 19 are formed on the same plane in the region P. The liquid crystal 21 is horizontal of the pixel electrode 17 and the common electrode 19 formed on the same substrate. It is operated by the electric field 23.

In this case, the liquid crystal 21 positioned between the common electrode 19 and the pixel electrode 17 is arranged in the same direction by a horizontal electric field 23 distributed between the common electrode 19 and the pixel electrode 17. In the transverse electric field method, a plurality of multi-domains can be configured in a single pixel area, and thus a liquid crystal display having a wider viewing angle can be manufactured.

FIG. 2 is a schematic cross-sectional view of a transverse electric field type liquid crystal display device in which a lower substrate and an upper substrate, which are array substrates having the above-described structure, are bonded to each other.

As shown, the transverse electric field type liquid crystal display device is formed by bonding the upper substrate 29 and the above-described array substrate 33 to each other, and an indium-tin-oxide is formed on the rear surface of the upper substrate 29. The back electrode 27 is formed by depositing a transparent conductive metal layer such as oxide), and an upper flat plate 31 is formed on the back electrode.

A lower polarizing plate 35 is formed under the lower substrate 33 corresponding to the upper polarizing plate 31.

A backlight (back light) 37, which is a back light source, is positioned below the lower polarizer 35, and the backlight 37 includes a plurality of diffusion sheets, a prism sheet, and the like to pass light to the front of the lower substrate. The film 39 is constructed.

The back electrode 27 serves to block static electricity applied from the outside.

In detail, when the liquid crystal panel contacts an externally charged object, charging of the upper substrate 29 may affect the arrangement state of the liquid crystal molecules 21 positioned below the upper substrate 29. do.

The amount of light passing through the liquid crystal is not controlled by the data voltage, which serves to deteriorate the image quality.

Therefore, the rear electrode 27 is formed on the rear surface of the upper substrate 29 to prevent the reduction of the image quality due to static electricity.

In this configuration, the static electricity generated in the upper substrate 29 may be prevented to some extent, but in the case of the lower substrate 33, the backlight film 39 and the polarizing plate 35 may be subjected to a subsequent module process and vibration shock. Static electricity generated in between can not be prevented.

As a result, there is a problem that black spots or white spots are generated when the panel is driven by the static electricity generated at the contact portion between the film 39 and the liquid crystal panel.

In addition, the artificial static elimination process to prevent the appearance of black stains or white stains takes a long time, there is a problem that the foreign material exposure defects increase due to the increase in the TAT and the increase in the external exposure time of the panel and the backlight.

Therefore, in order to solve the above problems, the present invention constitutes a conductive metal of a transparent material on the rear surface of the array substrate for a transverse electric field type liquid crystal display device, thereby releasing static electricity generated locally on the lower substrate to the outside. The purpose of the present invention is to manufacture a transverse electric field type liquid crystal display device which does not generate spots when driving a panel.

1 is a partial plan view of an array substrate for a transverse electric field type liquid crystal display device,

2 is a schematic cross-sectional view of a conventional transverse electric field type liquid crystal display device;

3A to 3C are cross-sectional views illustrating a manufacturing process of a transverse electric field type liquid crystal display device according to the present invention.

<Description of the symbols for the main parts of the drawings>

131: upper polarizer 135: lower polarizer

153: adhesive 155: second back electrode

According to an aspect of the present invention, there is provided a transverse electric field type liquid crystal display device comprising: an upper substrate having a first back electrode formed of a transparent conductive metal on one surface of a transparent first substrate; A lower substrate having a switching element, a pixel electrode and a common electrode formed on one surface of the second transparent substrate, and a second back electrode formed of a transparent conductive metal on the other surface thereof; A liquid crystal located between the upper substrate and the lower substrate; An upper polarizing plate formed on the first rear electrode; A lower polarizing plate formed under the second back electrode; It includes a light distribution device configured under the lower polarizing plate.

The first back electrode and the second back electrode are formed of one selected from a transparent conductive metal group consisting of indium tin oxide (ITO) and indium zinc oxide (IZO).

The switching element is a thin film transistor including a gate electrode, a source electrode, a drain electrode, and an active layer.

According to an aspect of the present invention, there is provided a method of manufacturing a transverse electric field liquid crystal display device, comprising: forming an upper substrate by placing a first back electrode of a transparent conductive metal on one surface of a transparent first substrate; Forming a lower array substrate by placing a switching element, a pixel electrode, and a common electrode on one surface of the transparent second substrate; Bonding the upper substrate and the lower substrate to form a liquid crystal panel; Forming a second back electrode of a transparent conductive metal on a lower surface of the liquid crystal panel; And forming an upper polarizing plate on an upper portion of the first rear electrode and a lower polarizing plate on a lower portion of the second rear electrode.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

Example

The present invention proposes a method of forming a conductor in the lower portion of the liquid crystal panel to remove the static electricity generated between the transverse electric field type liquid crystal panel and the backlight film.

Hereinafter, a manufacturing process of the transverse electric field type liquid crystal display device according to the present invention will be described with reference to FIGS. 3A to 3C.

In order to manufacture a liquid crystal display, an upper substrate, a lower substrate on which switching elements and array wiring are formed must be fabricated, respectively.

3A to 3C are schematic cross-sectional views illustrating a process of manufacturing the upper substrate.

First, FIG. 3A is a plan view illustrating an upper substrate, and includes indium-tin-oxide (ITO) and indium-zinc-oxide (IZO) on a transparent substrate 124. One selected from among the configured transparent conductive metal groups is deposited to form the first back electrode 127.

Next, an alignment layer 141 is formed on the other surface of the transparent substrate, which is a position corresponding to the first back electrode. There are various kinds of materials for forming the alignment layer, but generally a polyimide-based transparent polymer material is used.

In this manner, an upper substrate A which is the first substrate of the transverse electric field type liquid crystal display device is manufactured. If the color liquid crystal display device includes a black matrix (not shown) between the alignment layer 141 and the substrate 124 and a sub color filter (not shown) indicating red, green, and blue between the black matrix. It is enough to configure the color filter.

3B is a cross-sectional view illustrating a lower substrate as a second substrate of the transverse electric field liquid crystal display device.

As illustrated, the common electrode 119 and the pixel electrode 117 which induce a transverse electric field are spaced apart from each other on the transparent substrate 133, and the switching element T connected to the pixel electrode 117 is formed. . The switching element T includes a gate electrode 143, a source electrode 145, a drain electrode 147, and an active channel 149.

Next, an alignment layer 151 is formed on the entire surface of the substrate 133 on which the pixel electrode 117 and the switching element T are formed.

In this step it is possible to complete the rough lower substrate (B).

3C is a cross-sectional view of a transverse electric field type liquid crystal display device in which the upper substrate A and the lower substrate B are bonded to each other.

After the bonding process of bonding the upper substrate and the lower substrate (A) by the sealant (153), the transparent conductive metal as described above is deposited on the bottom of the lower substrate (B) to form a second rear positive electrode ( 155).

At this time, the transparent electrode for forming the second back surface electrode 155 is formed by depositing at room temperature or low temperature.

Next, the upper polarizer 131 and the lower polarizer 135 are attached to the upper part of the upper substrate A and the lower part of the lower substrate B, respectively.

As shown in the drawing, when the transparent conductive metal is deposited on the rear surface of the lower array substrate B to form the second rear electrode 155, static electricity is generated between the lower array substrate B and the backlight film 139. Even though the static electricity may be emitted to the outside through the second back electrode 155.

Accordingly, the transverse electric field type liquid crystal display device according to the present invention has an effect of improving image quality since the static electricity generated during the module mounting process or the vibration shock test, which is a continuous process after the liquid crystal panel is manufactured, can be emitted to the outside.

In addition, since the process time for removing static electricity generated in the lower substrate can be shortened, there is an effect of improving the yield of the product.

Claims (6)

An upper substrate having a first back electrode made of a transparent conductive metal on one surface of the first transparent substrate; A lower substrate having a switching element, a pixel electrode and a common electrode formed on one surface of the second transparent substrate, and a second back electrode formed of a transparent conductive metal on the other surface thereof; A liquid crystal located between the upper substrate and the lower substrate; An upper polarizing plate formed on the first rear electrode; A lower polarizing plate formed under the second back electrode; Light distribution device configured under the lower polarizer Transverse electric field type liquid crystal display device comprising a. The method of claim 1, And the first back electrode and the second back electrode are selected from a group of transparent conductive metals consisting of indium tin oxide (ITO) and indium zinc oxide (IZO). The method of claim 1, And the switching element is a thin film transistor including a gate electrode, a source electrode, a drain electrode, and an active layer. Forming an upper substrate by placing a first back electrode of a transparent conductive metal on one surface of the transparent first substrate; Forming a lower array substrate by placing a switching element, a pixel electrode, and a common electrode on one surface of the transparent second substrate; Bonding the upper substrate and the lower substrate to form a liquid crystal panel; Forming a second back electrode of a transparent conductive metal on a lower surface of the liquid crystal panel; Configuring an upper polarizer on the first back electrode and a lower polarizer on the lower part of the second back electrode; Method for manufacturing a transverse electric field type liquid crystal display device comprising. The method of claim 4, wherein And the first back electrode and the second back electrode are selected from a group of transparent conductive metals consisting of indium tin oxide (ITO) and indium zinc oxide (IZO). The method of claim 4, wherein And the switching element is a thin film transistor comprising a gate electrode, a source electrode, a drain electrode, and an active layer.