KR20000001679A - Reflection type liquid crystal display device and production method thereof - Google Patents

Abstract

PURPOSE: A reflection type liquid crystal display device is provided to prevent light leakage liable to take place in the open area and maximize photo efficiency. CONSTITUTION: The reflection type liquid crystal display element comprises; the 1st and 2nd substrate interposed in the liquid crystal layer; a data wiring(20) and gate wiring formed on the 1st substrate and to define the color area; a membrane transistor placed at the intersection of the data wiring and the gate wiring; a shade layer(24) formed on the open area between reflection electrodes.

Description

Reflective liquid crystal display device and manufacturing method thereof

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a reflective liquid crystal display device having a concave-convex reflection electrode and a manufacturing method thereof.

Since liquid crystal display devices are light-receiving devices, they can be classified into two types: a transmissive type requiring a separate light source and a reflective type using light from the outside. Generally, a transmissive liquid crystal display using a back light as a light source. Devices are widely used. However, the use of the backlight not only hinders the miniaturization of the liquid crystal display, but also has a disadvantage in that the use of the liquid crystal display is not possible because the backlight cannot be used where the power consumption is high and there is no power supply. In order to overcome the shortcomings of the liquid crystal display device having a backlight built-in, a research on a reflective liquid crystal display device using light from the outside as a light source has been actively conducted in recent years.

In the above-described reflective liquid crystal display device, the greatest concern is how much efficient use of ambient light is. Recently, various methods have been proposed, such as attaching an optical compensation film to the inside or outside of a cell or changing the structure of a reflector to cause scattering of reflected light.

U.S. Patent 5,500,750 proposes a reflecting plate in which the surface of the reflecting plate has an uneven shape for efficient use of light. In this patent, a liquid crystal layer is formed between a pair of substrates, a bump made of a photosensitive resin is formed on a lower plate, and an insulating film and a reflective electrode are successively stacked thereon. The reflective electrode on the thin film transistor (hereinafter referred to as TFT) only serves as a light shielding layer that is electrically insulated. The counter electrode is formed on the upper plate, and the black filter opens an open area between adjacent reflective electrodes. Blocking

However, the reflective liquid crystal display device has a complicated manufacturing process and proposes an inefficient structure for using ambient light. That is, the light shielding layer is formed in the direction of light incidence, not only to limit the incident area of light, but also when the two substrates are shifted when the upper and lower plates are bonded, light leakage in the open area between the reflective electrodes formed on the lower plate. The phenomenon occurs, which degrades the display quality, which makes the bonding process very difficult.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and is formed by bending a photoresist film having a function of a protective film on a TFT substrate to form a bend, and forming a reflective electrode thereon, thereby forming a reflection type with excellent light efficiency in a simple process. It is an object to provide a liquid crystal display device.

Another object of the present invention is to form a light shielding layer on the TFT substrate of the liquid crystal display device to prevent leakage of light that may occur in an open region of neighboring reflective electrodes and to improve the efficiency of incident light.

In order to achieve the above object, the liquid crystal display device according to the present invention comprises a TFT substrate and a counter substrate having a liquid crystal layer interposed therebetween, a photoresist film formed of a photosensitive resin formed on the TFT substrate, and on the photoresist film. A light blocking layer covering a part of the data wiring and the gate wiring and electrically connected to the drain electrode of the thin film transistor through a contact hole, and a light blocking layer formed on an open region between neighboring reflective electrodes to prevent leakage of light; The main components include a first alignment layer formed on the electrode and the light shielding layer, a transparent counter electrode formed on the counter substrate and driving the liquid crystal by applying a voltage to the liquid crystal layer together with the reflective electrode, and a second alignment layer formed on the counter electrode. It is characterized by.

In another embodiment of the present invention, an open area exists in the TFT area as well as data wiring, and a light shielding layer is formed on each open area to maximize light efficiency and prevent light leakage that may occur in the open area. do.

In the method of manufacturing the liquid crystal display device of the present invention, first, a photoresist film is formed of a photosensitive polymer resin on a TFT substrate, and then the surface of the photoresist film is partially etched so that the surface has continuous bending. Thereafter, a reflective electrode is formed along the curved surface of the photoresist film, and a first alignment film is formed thereon. After the counter electrode is formed on the counter substrate side, a second alignment film is formed thereon. Subsequently, the two substrates are bonded together under a constant cell gap, and then liquid crystal is injected therebetween to complete the liquid crystal display device.

1A is a plan view of a reflective liquid crystal display device according to a first embodiment of the present invention.

1B is a cross-sectional view taken along the line A-A of FIG. 1A.

2A is a plan view of a reflective liquid crystal display device according to a first embodiment of the present invention.

FIG. 2B is a cross sectional view along line B-B in FIG. 2A; FIG.

3 is a cross-sectional view of region C of FIG. 1A;

<Explanation of symbols for main parts of the drawings>

10a ---- TFT substrate 10b ---- Optical substrate

12 ----- gate electrode 14 ----- gate insulating film

16 ----- semiconductor layer 18 ----- omic contact layer

19a ---- source electrode 19b ---- drain electrode

20 ----- Data Wiring 22 ----- Photoresist Film

24 ----- Shading Layer 26 ----- Reflective Electrode

28 ----- contact hole 29 ----- counter electrode

30a ---- first alignment layer 30b ---- second alignment layer

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1A is a plan view of a reflective liquid crystal display device according to a first exemplary embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along line AA of FIG. 1A. As shown in the drawing, a gate wiring is formed on a TFT substrate (first substrate 10a). (11), data wirings 20 and gate electrodes 12 are formed, and a gate insulating film 14 is formed over the entire substrate 10a. On the gate insulating film 14, a semiconductor layer 16, an ohmic contact layer 18, a source electrode 19a and a drain electrode 19b constituting the TFT are formed together with the gate electrode 12. On the TFT region and the data wiring 20, a photoresist film 22 having a curved shape with a continuous surface thereof is formed. A light blocking layer 24 is formed on the photoresist film 22, and the reflective electrode 26 is connected to the drain electrode 19b through the contact hole 28 in the form of the photoresist film 22. The first alignment layer 30a covers the top. On the counter substrate (second substrate 10b), a color filter layer comprising an opposing electrode 29 for driving a liquid crystal by applying an electric field to the liquid crystal layer together with the reflective electrode 26 and a color filter element of R, G, and B (not shown). (Not shown) is formed, and the second alignment film 30b is covered thereon.

A method of manufacturing a liquid crystal display device having the above structure will be described with reference to FIG. 2B.

First, Ta, Cr, Al, and the like are stacked on the substrate 10a by sputtering, and then patterned to form the gate electrode 12. Thereafter, an inorganic material such as SiNx or SiOx is deposited by plasma enhanced chemical vapor deposition (PECVD) to form a gate insulating film 14, and then a material such as a-Si: H and n ⁺ a-Si: H And then patterned to form semiconductor layer 16 and ohmic contact layer 18, and sputtering a material such as Ti, Cr / Al, Cr / Al-Ta, or Cr / Al / Al-Ta The source electrode 19a, the drain electrode 19b, and the data wiring 20 are formed by laminating by the method.

The patterning of the photoresist film 22 on the TFT region and the data wiring 20 is performed by first applying a photosensitive polymer resin such as an acrylic resin, and then masking the surface having holes of any shape. The light is irradiated and then irradiated with light. The surface of the photoresist film 22 is partially exposed to an etched or non-etched region by light irradiated through the hole of the mask. At this time, the etching region is preferably 0.1 to 0.5d, where d represents the thickness of the photoresist film and is mostly in the range of 1 to 5 mu m. Subsequently, partial development is carried out using a developer so that the surface of the photoresist film 22 is curved. In the above-described process, the shape of the bend on the surface of the photoresist film 22 (difference between the acid and the valley) depends on the exposing time and / or the developing time, and the light used is preferably ultraviolet light. . Subsequently, a metal having a high reflectance such as Al or Ag is deposited on the photoresist film 22 by a deposition method or a sputtering method to form a reflective electrode 26, which forms the contact hole 28. It is connected to the drain electrode 19b of a TFT through.

Reference numeral 24 denotes a light shielding layer, and is formed by applying a material such as black resin to an open region between one data wiring 20 and a neighboring reflective electrode sharing the gate wiring 11.

The first alignment layer 30a is formed on the reflective electrode 26 by applying a photoalignment material such as polysiloxane, polyvinylcinnamate, or cellulosecinnamate. Thereafter, the polarized or unpolarized light is subjected to alignment treatment by one or more irradiations, wherein the light is preferably ultraviolet. The first alignment layer 30a may also be formed by applying a material such as polyimide, polyamide, polyvinylalcohol, polyamic acid, or SiO ₂ . In this case, orientation is carried out by a rubbing method.

The counter electrode 29 is formed by stacking a transparent metal such as indium tin oxide (ITO) by sputtering. The second alignment layer 30b may be formed by a photoalignment method or a rubbing method as in the first alignment layer 30a.

FIG. 2A is a plan view of a reflective liquid crystal display device according to a second embodiment of the present invention, and FIG. 2B is a cross-sectional view taken along the line BB of FIG. 2A. The second embodiment is different from the first embodiment in that it is a reflective electrode of a TFT region. This suppresses the occurrence of an abnormal electric field that may occur between the electrodes, thereby extending the light shielding layer to the TFT region.

In the second embodiment, the same reference numerals as in the drawings used in the first embodiment apply.

FIG. 3 is a cross-sectional view of region C of FIG. 1A, in which data wirings 24 formed on the insulating film 14 are shared by neighboring reflective electrodes 26, and an open region between the reflective electrodes 26 is shown. It is blocked by the light shielding layer 24. Reference numeral 30a in the drawing denotes a first alignment film, and reference numeral 10a denotes a TFT substrate.

According to the present invention, it is possible to provide a reflective liquid crystal display excellent in light efficiency by a simple process by partially etching the photoresist film to form continuous bending and forming a reflective electrode thereon.

In addition, the present invention prevents light leakage that may occur in an open region of a neighboring reflective electrode by forming a light shielding layer on the TFT substrate, maximizes the efficiency of light incident through the opposing substrate, and also in the process of bonding the substrate. Very advantageous.

Claims (13)

The first and second substrates having a liquid crystal layer therebetween; At least a pair of data and gate wirings formed on the first substrate and defining a pixel region; A thin film transistor formed at an intersection point of the data line and the gate line; A photoresist film formed on the data line, the gate line, and the thin film transistor to have a curved surface; A plurality of reflective electrodes electrically connected to the drain electrodes of the thin film transistors on the photoresist film; A reflective liquid crystal display device comprising a light shielding layer formed on an open area between adjacent reflective electrodes. The reflective liquid crystal display of claim 1, wherein the reflective electrode is formed in a region excluding the thin film transistor. The reflective liquid crystal display of claim 1, wherein the neighboring reflective electrodes share part of the data and gate wirings. 4. The reflective liquid crystal display device according to claim 1 or 3, wherein the reflective electrodes apply a voltage to the liquid crystal layer together with the counter electrode on the second substrate. The reflective liquid crystal display device of claim 1, wherein the light blocking layer is made of black resin. The reflective liquid crystal display of claim 1, further comprising a first alignment film formed on the first substrate and a second alignment film formed on the second substrate. The material constituting the first alignment layer or the second alignment layer is selected from the group consisting of polysiloxanecinnamate, polyvinylcinnamate and cellulosecinnamate. Reflective liquid crystal display device. According to claim 6, wherein the material constituting the first alignment layer or the second alignment layer is a group consisting of polyimide, polyamide, polyvinylalcohol, polyamic acid and SiO ₂ Reflective liquid crystal display device, characterized in that selected from. Preparing a substrate; Forming a thin film transistor element on the substrate; Forming a photoresist film on the substrate and the thin film transistor element; Patterning the photoresist film; Forming a light shielding layer on the photoresist film; And forming a reflective electrode on the photoresist film and the light shielding layer. 10. The method of claim 9, wherein the forming of the thin film transistor element comprises forming a gate line and a data line. The method of manufacturing a reflective liquid crystal display device according to claim 9 or 10, wherein the reflective electrode covers a part of the gate wiring and the data wiring. The method of claim 9, wherein the patterning of the photoresist film comprises: Irradiating light onto the photoresist film, A method of manufacturing a reflective liquid crystal display device comprising the step of partially etching a photoresist film irradiated with light. The method of manufacturing a reflective liquid crystal display device according to claim 12, wherein the irradiating light onto the photoresist film comprises a partial exposure step in which the etching region and the non-etching area are etched according to the type of the irradiated light.