KR20000066093A - Reflective LCD - Google Patents

Abstract

PURPOSE: A reflective type LCD is provided to focus light scattered into sides to a direction perpendicular to a screen, thereby enhancing a front transmissibility. CONSTITUTION: A reflective type LCD comprises bottom and top substrates(20,40), a liquid crystal layer(50), a reflective film(25), black matrixes(420), color filters(44), a polarizer(48), and anti-reflective film(43). The liquid crystal layer(50) is inserted between the substrates(20,40). The black matrixes(420) are arrayed to define unit cell on the bottom substrate. The filters are surrounded by the black matrixes. The polarizer is disposed on outer surface of the top substrate. The reflective film(25) comprises a reflective metal layer with plural semi-spherical grooves, and protrudes(24) disposed on the metal layer and having the anti-reflective film(43) coated.

Description

Reflective Liquid Crystal Display {Reflective LCD}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflective liquid crystal display device, and more particularly, to a reflective liquid crystal display device capable of improving transmittance in a normal direction of a screen, which is a main viewing angle region.

In general, a reflective liquid crystal display device does not require a backlight and is applied to a portable display device requiring low power consumption.

In particular, as the market for mobile phones and portable devices expands, the necessity of a reflective liquid crystal display device is increasing.

In the reflective liquid crystal display, when natural light is incident from the upper substrate, light is reflected again through the pixel electrode. At this time, light is absorbed or passed through the polarizer according to the arrangement state of the liquid crystal molecules.

Such a conventional reflective liquid crystal display device will be described with reference to FIG. 1.

As shown in FIG. 1, the lower substrate 1 and the upper substrate 5 face each other at a predetermined distance. The liquid crystal layer 10 is interposed between the lower substrate 1 and the upper substrate 5. The pixel electrode 2 is provided on the inner surface of the lower substrate 1.

On the inner side of the upper substrate 5, a black matrix 6 defining the unit pixels is arranged, and a color filter 7 is disposed in the unit pixels surrounded by the black matrix 6. The common electrode 8 is provided on the surface of the black matrix 6 and the color filter 7.

A polarizing plate 11 for linearly polarizing natural light is disposed on the outer surface of the upper substrate 5, and a reflecting plate 13 having several reflection protrusions 13a is disposed on the outer surface of the lower substrate 1.

In such a reflective liquid crystal display device, when natural light is incident from an upper portion of the upper substrate 5, passes through the polarizing plate 11 and the liquid crystal layer 10, and reaches the reflecting plate 13, it is reflected by the reflecting plate 13. The display is realized through the liquid crystal layer 10 and the polarizing plate 11.

In the reflective liquid crystal display, the reflector 13 is provided with a hemispherical reflector 13a. Accordingly, when light is reflected from the reflecting plate 13, the reflecting layer 13a has a transmittance in the viewing angle direction but is not sufficient.

That is, due to the hemispherical reflection protrusion 13a, the light is dispersed to the side, and the amount of light is actually very low in the normal direction of the screen as viewed by the user.

Accordingly, an object of the present invention is to solve the above-mentioned conventional problems, and to provide a reflective liquid crystal display device capable of improving front transmittance by concentrating light scattered to the side in the normal direction of the screen.

1 is a cross-sectional view of a conventional reflective liquid crystal display device.

2 is a cross-sectional view of a reflective liquid crystal display device according to an exemplary embodiment of the present invention.

3 is a cross-sectional view of a reflective liquid crystal display device according to another exemplary embodiment of the present invention.

(Explanation of symbols for the main parts of the drawing)

20-lower substrate 23-aluminum metal layer

24-protrusion 25-condensing reflector

40-Top Board 42-Black Medium

43-anti-reflective film 45-organic light emitting layer

48-polarizer

In order to achieve the above object of the present invention, according to an embodiment of the present invention, the present invention is opposed to each other at a predetermined distance and the upper and lower substrates having a unit cell defined, and the liquid crystal layer interposed between the upper and lower substrates; And a reflection plate disposed on the inner side of the lower substrate, a black matrix arranged to define a unit cell on the inner side of the upper substrate, a color filter disposed on the portion surrounded by the black matrix, and a disposition on the outer side of the upper substrate. A reflective liquid crystal display device comprising a polarizing plate, wherein the reflecting plate is disposed on a reflective metal layer provided with several hemispherical grooves and a non-reflective film disposed on the reflective metal layer outside the grooves to prevent leakage of reflected light. And a non-reflective film is coated on the surface of the black matrix.

An organic light emitting layer for amplifying light is further provided on the black matrix and the surface of the color filter, and the reflective metal layer is aluminum.

According to the present invention, in order to increase the transmittance in the normal direction of the screen mainly seen by the user in the reflective liquid crystal display device, several hemispherical grooves are formed on the reflecting plate surface, and the light reflected on the reflecting plate surfaces on both sides of the groove is mainly used. While forming the protrusions, the anti-reflective film is formed on the surface of the black matrix so that the light can be collected around the black matrix. As a result, the light reflected from the side surface can be focused to the center portion, and the transmittance in the normal direction of the screen is greatly improved.

(Example)

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

2 is a cross-sectional view of a reflective liquid crystal display according to an exemplary embodiment of the present invention, and FIG. 3 is a cross-sectional view of a reflective liquid crystal display according to another exemplary embodiment of the present invention.

Referring to FIG. 2, the lower substrate 20 and the upper substrate 40 are spaced apart from each other by a predetermined distance, and the liquid crystal layer 50 including liquid crystal molecules is disposed between the lower substrate 20 and the upper substrate 40. It is interposed. In this case, although not shown in the drawing, the lower substrate 20 includes gate bus lines, data bus lines, and thin film transistors.

The light collecting reflector 25 according to the present invention is disposed on the inner surface of the lower substrate 20. At this time, the light converging reflector 25 in the present invention is a metal layer having excellent reflection characteristics in which several hemispherical grooves h are formed, for example, an aluminum metal layer 23 and an aluminum metal layer 23 on both sides of the hemispherical grooves h. It includes a protrusion 24 protruding to a predetermined height on the top. At this time, the antireflection film 24a is covered on the surface of the protrusion part 24. At this time, most incident light is focused in the normal direction of the screen by the hemispherical groove (h), and the light reaching the side of the groove (h) is collected by the protrusions 24 to the center portion of the groove (h) To prevent light leakage.

Here, a pixel electrode may be formed in the lower substrate 20, and the light collecting reflector 25 may be used as the pixel electrode.

The black matrix 420 is disposed on the inner surface of the upper substrate 40 to define the unit pixel, and the color filter 44 is disposed in the space surrounded by the black matrix 420. The surface has a convex shape.

The black matrix 420 includes a black medium 42 and an antireflective film 43 covering the surface of the black medium 42. The black medium 42 is generally made of an opaque metal film or an opaque resin. Here, the anti-reflective film 43 covering the black medium 42 prevents light from being diffused in the lateral direction of the screen, not in the direction of the angle of view.

On the surface of the color filter 44 and the black matrix 420, an organic emission layer 45 for amplifying light is disposed. Here, the organic light emitting layer 45 is disposed below the color filter 44 and the black matrix 420, so that the light transmitting ability of the reflective liquid crystal display itself is very low.

Although not shown in the figure, a common electrode is disposed on the surface of the organic light emitting layer 45.

On the other hand, the polarizing plate 48 is disposed on the outer surface of the upper substrate 40.

When natural light is incident on the upper substrate of the reflective liquid crystal display device, the polarized light is linearly polarized by the polarizing plate 48, and the linearly polarized light passes through the liquid crystal layer 50 to reach the light converging reflector 25. The light reaching the condensing reflector 25 passes through the condensing reflector 25 and is reflected back toward the upper substrate. The condensed groove h has a curvature on the surface of the condensing reflector 25. The light diffused to the side is concentrated in the center, that is, the normal direction of the screen by the protrusion 24 of the light collecting reflector 25. Accordingly, the reflector 25 serves as a condenser lens.

The first reflected light passes through the liquid crystal layer 5 and is transmitted to the organic light emitting layer 45. At this time, the light is amplified by the organic light emitting layer 45 and dispersed into the color filter 44. At this time, in the process of transmitting light into the color filter 44, the light may be distributed to some sidewalls. However, the light scattered into the color filter 44 hits the side wall of the black matrix 420 covered with the anti-reflective film 43 and is collected again toward the center. Therefore, a large amount of light is transmitted in the main viewing angle area that is mainly viewed by the user, that is, the normal direction of the screen.

3, the same effect can be obtained by attaching the light collecting reflector 25 to the outer surface of the lower substrate 20.

As described in detail above, according to the present invention, in order to increase the transmittance in the normal direction of the screen mainly seen by the user in the reflective liquid crystal display, several hemispherical grooves are formed on the surface of the reflecting plate, and the reflecting plates on both sides of the grooves. While forming a projection that collects light reflected on the surface, a non-reflective film is formed on the surface of the black matrix to collect light.

As a result, the light reflected from the side surface can be focused to the center portion, and the transmittance in the normal direction of the screen is greatly improved.

In addition, this invention can be implemented in various changes within the range which does not deviate from the summary.

Claims (4)

Upper and lower substrates opposed to each other by a predetermined distance and having a unit cell defined therein; A liquid crystal layer interposed between the upper and lower substrates; A reflector disposed on an inner surface of the lower substrate; A black matrix arranged to define a unit cell on an inner surface of the upper substrate; Color filters disposed at portions surrounded by the black matrix; A reflective liquid crystal display device including a polarizer disposed on an outer surface of the upper substrate. The reflecting plate includes a reflective metal layer having several hemispherical grooves, and a protrusion disposed on the reflective metal layer outside the groove and coated with an antireflective film to prevent leakage of reflected light. A reflection type liquid crystal display device, wherein an anti-reflection film is also coated on the surface of the black matrix. The reflective liquid crystal display of claim 1, wherein an organic light emitting layer for amplifying light is further provided on the surface of the black matrix and the color filter. The reflective liquid crystal display device according to claim 2, wherein the reflective metal layer is aluminum. Upper and lower substrates opposed to each other by a predetermined distance and having a unit cell defined therein; A liquid crystal layer interposed between the upper and lower substrates; A reflector disposed on an outer surface of the lower substrate; A black matrix arranged to define a unit cell on an inner surface of the upper substrate; Color filters disposed at portions surrounded by the black matrix; A reflective liquid crystal display device including a polarizer disposed on an outer surface of the upper substrate. The reflective plate includes a reflective metal layer provided with several hemispherical grooves, and a protrusion disposed on the reflective metal layer outside the groove and coated with an antireflective film on the surface thereof. A reflection type liquid crystal display device, wherein an anti-reflection film is also coated on the surface of the black matrix.