KR20060078072A - Liquid crystal display apparatus - Google Patents

Abstract

A liquid crystal display device capable of improving the yield of a product is disclosed. The liquid crystal display device includes a color filter layer having a transmission hole formed by removing a portion thereof to provide white light to the reflective electrode, and a gap adjusting member formed in the transmission hole. The gap adjusting member is formed to have the same thickness as the color filter layer to keep the cell gap uniformly in the region where the reflective electrode is formed. Accordingly, the liquid crystal display may prevent particles generated during the process from being combined with the gap adjusting member on the upper surface of the color filter layer, thereby preventing short circuit of the two substrates by the particles, thereby improving product yield. have.

Reflective-transmission mode, double cell gap, white light

Description

Liquid crystal display device {LIQUID CRYSTAL DISPLAY APPARATUS}

1 is a partial plan view of a liquid crystal display according to an exemplary embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the line II ′ of FIG. 1.

3 is a partial perspective view illustrating the second substrate illustrated in FIG. 2.

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

100: first substrate 110, 210: transparent substrate

120: gate line 130: data line

140: thin film transistor 150: protective film

160: organic insulating film 170: pixel electrode

180: reflective electrode 200: second substrate

220: color filter layer 230: gap control member

240: common electrode 300: liquid crystal layer

The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device that can improve the yield of the product.

In general, the liquid crystal display is a type of flat panel display and displays an image by using optical characteristics of the liquid crystal. The liquid crystal display device includes a liquid crystal display panel displaying an image corresponding to an input image signal using light and a backlight assembly providing light to the liquid crystal display panel.

The liquid crystal display may be classified into a transmissive liquid crystal display for displaying an image using internal light provided from the backlight assembly, and a reflection-transmissive liquid crystal display for displaying an image using internal light and external artificial light or natural light. .

The liquid crystal display panel applied to the reflective-transmissive liquid crystal display device has a first substrate having a reflective electrode and a pixel electrode reflecting artificial light or natural light on the organic insulating layer, and a color filter layer, and are coupled to the first substrate opposite to each other. A second substrate and a liquid crystal layer interposed between the first substrate and the second substrate are provided.

Looking at the movement path of the light in the reflection mode, the external light passes through the color filter layer to be incident on the reflective electrode, reflected by the reflective electrode is provided back to the color filter layer. As such, since external light passes through the color filter layer and is provided to the reflective electrode, the light incident on the reflective electrode cannot be white light. As a result, the liquid crystal display panel cannot display normal colors when displaying an image using external light.

The liquid crystal display panel includes a hole for partially transmitting a color filter layer positioned corresponding to the reflective electrode to transmit white light to provide white light to the reflective electrode. As described above, when the hole is formed, since the cell gap of the portion where the hole is formed is larger than that of other regions, the cell gap of the reflective region is unevenly formed. In the liquid crystal display panel, an overcoat layer is formed on the upper surface of the color filter layer to uniformly form the cell gap of the reflective region.

The organic insulating layer formed on the first substrate has a via hole formed by removing a transmission region through which internal light is transmitted to maximize light utilization efficiency. As a result, in the liquid crystal display panel, the cell gap of the transmission region is larger than the cell gap of the reflection region. In general, since the response speed of the liquid crystal decreases when the cell gap is increased, the cell gap of the transmission region should be made as small as possible.

As such, when the cell gap is formed small, the distance between the pixel electrode formed on the first substrate and the common electrode formed on the second substrate is shortened, so that the pixel electrode and the common electrode may be shorted to cause a bright point defect.

In particular, foreign particles generated during the formation of the second substrate are the main cause of shorting the two electrodes. That is, when particles generated in the process of forming the color filter layer remain on the second substrate, the overcoat layer covers the upper surface of the particles. Since the overcoat layer is formed of a very high viscosity material, the particles harden rapidly. When the particle is covered by the overcoat layer, because the size of the particle is increased, the cell gap of the portion where the particle is located becomes smaller than the cell gap of other regions. In particular, when particles are formed in the reflective region having a small cell gap, the pixel electrode and the common electrode may be shorted.

An object of the present invention is to provide a liquid crystal display device which can improve the yield of a product by making the cell gap of the reflective region uniform.

A liquid crystal display device according to one feature for realizing the object of the present invention described above comprises a first substrate, a second substrate, and a liquid crystal layer.

The first substrate is provided with a reflective electrode that reflects light. The second substrate has a color filter layer and a gap adjusting member and is coupled to the first substrate so as to face each other. The color filter layer has a transmission hole formed by removing a portion thereof, and expresses a predetermined color using light. The gap adjusting member is provided in the transmission hole to uniformly maintain the cell gap with the first substrate. The liquid crystal layer is interposed between the first substrate and the second substrate to adjust the transmittance of light.

According to the liquid crystal display, the gap adjusting member is formed in the transmission hole, thereby preventing particles generated during the process from being combined with the gap adjusting member on the upper surface of the color filter layer, and preventing the two substrates from being shorted by the particles. can do.

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

1 is a plan view illustrating a liquid crystal display according to an exemplary embodiment of the present invention.

Referring to FIG. 1, the liquid crystal display according to the present invention includes a gate line 120 extending in a first direction D1 and data extending in a second direction D2 perpendicular to the first direction D2. A line 130 and a thin film transistor (TFT) 140 electrically connected to the gate line 120 and the data line 130 are included.

In more detail, the gate line 120 is insulated from the data line 130 and transmits a gate signal. The data line 130 carries a data signal. The gate line 120 and the data line 130 are made of an aluminum alloy such as aluminum (Al) or aluminum neodymium (AlNd), and a conductive metal material such as chromium (Cr) and molybdenum (Mo). It is made of aluminum alloy.

The TFT 140 is positioned in each pixel area P, and applies a signal voltage to a liquid crystal layer (not shown), and cuts it off. The pixel region P is a basic unit for displaying an image and is defined by the gate line 120 and the data line 130. The TFT 140 is positioned adjacent to a point where the gate line 120 and the data line 130 cross each other in the pixel area P.

The liquid crystal display includes a reflective electrode 180 that reflects artificial light or natural light provided from the outside. The reflective electrode 180 is located in the pixel area P. The reflective electrode 180 has a transmission window 181 formed by removing a portion of the reflective electrode 180 so as to transmit light provided from a backlight assembly (not shown).

Although not shown in the drawings, the liquid crystal display includes a color filter layer that expresses a predetermined color by using light provided from the backlight assembly and light provided from the outside. The color filter layer is formed of color pixels, and the color pixels are provided in the pixel areas P.

FIG. 2 is a cross-sectional view taken along the line II ′ of FIG. 1.

1 and 2, the liquid crystal display device may include a first substrate 100, a second substrate 200 coupled to the first substrate 100 to face each other, and the first substrate 100. The liquid crystal layer 300 is provided between the second substrate 200.

The first substrate 100 is disposed on the first transparent substrate 110, the TFT 140 formed on the first transparent substrate 110, and the first transparent substrate 110 on which the TFT 140 is formed. On the passivation layer 150, the organic insulating layer 160 provided on the upper surface of the passivation layer 150, the pixel electrode 170 provided on the upper surface of the organic insulating layer 160, and the upper surface of the pixel electrode 170. The reflective electrode 180 is provided.

The first transparent substrate 110 is a transparent material such as glass, quartz, sapphire, etc. to transmit the first light L1 provided from a backlight assembly (not shown) disposed below the first transparent substrate 110. Is made of. The first transparent substrate 110 is divided into a transmission area TA through which the first light L1 is transmitted and a reflection area RA through which the second light L2 provided from the outside is reflected.

The TFT 140 is disposed in the reflective region RA of the first transparent substrate 110, and applies a signal voltage corresponding to each pixel region P to the liquid crystal layer 300 and blocks the signal. .

In detail, the TFT 140 is connected to the gate line 120 to protect the gate electrode 141, the gate electrode 141, and the gate line 120 to receive the gate signal. ), An active layer 143 formed on an upper surface of the gate insulating layer 142, an ohmic contact layer 144 formed on an upper surface of the active layer 143, and a source electrode 145 formed on an upper surface of the ohmic contact layer 144. ), And a drain electrode 146.                     

In detail, the gate electrode 141 is branched from the gate line 120, and is simultaneously formed with the gate line 120.

The gate insulating layer 142 is provided on the first insulating substrate 110 on which the gate electrode 141 is formed. The gate insulating layer 142 is partially removed from the reflective area TA. The gate insulating layer 142 is made of an inorganic insulating material such as silicon oxide (SiO ₂ ) or silicon nitride (SiN _X ) which has good adhesion to a metal material and suppresses formation of an air layer at an interface. The gate insulating layer 142 is formed by a plasma-enhanced chemical vapor deposition (PECVD) method, and preferably has a thickness of about 4500 kPa.

On the upper surface of the gate insulating layer 142, the active layer 143 made of amorphous silicon and the ohmic contact layer 144 made of n + amorphous silicon are sequentially provided.

The active layer 143 is provided at a position corresponding to the gate electrode 141. The ohmic contact layer 144 made of amorphous silicon doped with n ⁺ is disposed on an upper surface of the active layer 143. The ohmic contact layer 144 may be removed to form a channel region partially exposing the active layer 143.

The source electrode 145 and the drain electrode 146 are provided on an upper surface of the ohmic contact layer 144 branched to both sides of the channel region.

The source electrode 145 is branched from the data line 130 (see FIG. 3) to receive the data signal. A first end of the source electrode 145 is positioned on an upper surface of the gate insulating layer 142, and a second end of the source electrode 145 opposite to the first end is positioned on an upper surface of the ohmic contact layer 144.

The drain electrode 146 is positioned to face the source electrode 145 around the channel region. A first end of the drain electrode 146 is positioned on an upper surface of the gate insulating layer 142, and a second end of the drain electrode 146 opposite to the first end is positioned on an upper surface of the ohmic contact layer 144.

The protective layer 150 made of an inorganic insulating material, for example, silicon oxide (SiO ₂ ) or silicon nitride (SiN _X ), is provided on the insulating substrate 110 on which the TFT 140 is formed. The passivation layer 150 covers the TFT 140 and is partially positioned on the top surface of the gate insulating layer 142.

The organic insulating layer 160 provided on the upper surface of the protective film 150 is made of a photosensitive acrylic resin. A portion of the passivation layer 150 and the organic insulating layer 160 positioned in the reflective area TA is removed to form a contact hole 161 partially exposing the drain electrode 141. In this case, a first end of the drain electrode 161 is partially exposed through the contact hole 161.

The gate insulating layer 142, the passivation layer 150, and the organic insulating layer 160 positioned in the transmission area TA are removed to form a via hole 162 to reduce the loss of the first light L1. do.                     

The upper surface of the organic insulating layer 160 is formed with an uneven portion for front reflection of the second light (L2).

The pixel electrode 170 provided on the upper surface of the organic insulating layer 160 partially covers the organic insulating layer 160 in the reflective region RA, and the first transparent substrate in the transmissive region TA. 110 is located on the upper surface. The pixel electrode 170 is made of indium tin oxide (ITO) or indium zinc oxide (IZO). The pixel electrode 170 is electrically connected to the drain electrode 146 through the contact hole 161 to receive the signal voltage from the TFT 140.

The reflective electrode 180 is provided on the pixel electrode 170. The reflective electrode 180 is positioned in the reflective region RA and is positioned on an upper surface of the pixel electrode 170. The reflective electrode 180 has the transmission window 181 formed by removing the transmission area TA to provide the first light L1 to the liquid crystal layer 300. The transmission window 181 is positioned to correspond to the via hole 162.

The second substrate 200 is provided on the first substrate 100. The second substrate 200 uniformly uniforms the cell gap in the second transparent substrate 210, the color filter layer 220 provided on the second transparent substrate 210, and the reflective region RA. A gap adjusting member 230 for holding and a common electrode 240 provided on the color filter layer 220 is provided.

The second transparent substrate 210 is made of the same material as the first transparent substrate 110.

The color filter layer 220 formed by the thin film process passes through the liquid crystal layer 300 and uses a predetermined color using the first and second lights L1 and L2 provided to the color filter layer 220. Color pixels 221 expressing a color, and a black matrix 223 surrounding each color pixel.

Each of the color pixels has a transmission hole 222 formed by partially removing the second light L2 to the reflective electrode 180 in the form of white light. The transmission hole 222 is located in the reflection area TA.

Looking at the exit path of the second light (L2), the second light (L2) is incident to the reflective electrode 180 through the transmission hole 222. Light incident on the reflective electrode 180 is reflected toward the second substrate 200 and is incident on the color pixels.

The black matrix 223 blocks the light leaking from each color pixel to improve the contrast ratio (C / R). The TFT 140 provided in the first substrate 100 is provided in a region corresponding to the black matrix 223 so as not to recognize the TFT 140 from the outside.

The gap adjusting member 230 is provided in the transmission hole 223. The gap adjusting member 230 is made of a transparent material so that the second white light L2 is provided to the reflective electrode 180. The gap adjusting member 230 is made of a photocurable organic material patterned using ultraviolet (UV), like the organic insulating layer. Accordingly, since the gap adjusting member 230 is easy to pattern through a photolithography process, the gap adjusting member 230 may cover the particles generated in the process of forming the color pixels 221 to prevent the particles from growing.

That is, since the gap adjusting member 230 is located in the transmission hole 222, even if the particles are generated on the upper surfaces of the color pixels 221, they do not cover the particles. Accordingly, the liquid crystal display device can prevent the pixel electrode 170 and the common electrode 240 from being shorted with each other by the particles, thereby improving the yield of the product.

Since the color pixels 221 are removed in the reflective region RA, the region in which the transmission hole 222 is formed, a cell gap is larger than that of other regions. The gap adjusting member 230 is formed at the same height as the color pixels 221 to uniformly maintain a cell gap in the reflection area RA. Accordingly, the liquid crystal display may provide white light to the reflective electrode 180 while maintaining a uniform cell gap in the reflective region RA. For this reason, the liquid crystal display device can improve the utilization efficiency of light, thereby improving display characteristics.

The common electrode 240 provided on the upper surface of the color filter layer 220 and the gap control member 230 is made of a transparent conductive metal such as ITO or IZO, and the common voltage is applied to the liquid crystal layer 300. Is applied.

The liquid crystal layer 300 interposed between the first substrate 100 and the second substrate 200 is an electric field formed between the pixel electrode 170 and the common electrode 240. The transmittance of the second light L2 reflected by the first light L1 and the reflective electrode 180 is adjusted.

3 is a partial perspective view illustrating the second substrate illustrated in FIG. 2.

3 illustrates the gap adjusting member 230 and the common electrode 240 in order to clearly illustrate the transmission hole 222.

Referring to FIG. 3, the color pixels 221 and the black matrix 224 are formed on an upper surface of the second transparent substrate 210. The color pixels 221 are formed of RGB color pixels 221a, 221b, and 221c. One pixel of the RGB color pixels 221a, 221b, and 221c is positioned in each pixel area P (see FIG. 1). The transmission hole 222 is formed in each of the color pixels 221a, 221b, and 221c. A portion of the second transparent substrate 210 is exposed through the transmission hole 222.

According to the present invention described above, the liquid crystal display includes a color filter layer having a transmission hole formed by removing a portion of the liquid crystal display to provide white light to the reflective electrode, and a gap adjusting member positioned in the transmission hole. The gap adjusting member is formed to the same thickness as the color filter layer to keep the cell gap uniform in the reflection area. Accordingly, the liquid crystal display may prevent particles generated in the process of forming the color filter layer from being combined with the gap adjusting member on the upper surface of the color filter layer. As a result, the liquid crystal display device can prevent the pixel electrode and the common electrode from being shorted by the particles, thereby improving the yield of the product.

In addition, since the liquid crystal display device can provide white light to the reflective electrode by using the gap adjusting member and maintain the cell gap of the reflective region uniformly, display characteristics can be improved.

Although described above with reference to the embodiments, those skilled in the art can be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below. I can understand.

Claims (5)

A first substrate having a reflective electrode for reflecting light; It has a transmission hole formed by removing a portion, a color filter layer for expressing a predetermined color using the light, and a gap adjusting member provided in the transmission hole to uniformly maintain a cell gap with the first substrate; A second substrate coupled to the first substrate so as to face each other; And And a liquid crystal layer interposed between the first substrate and the second substrate to adjust the transmittance of the light. The liquid crystal display of claim 1, wherein the gap adjusting member is made of a transparent photocurable organic material. The liquid crystal display of claim 1, wherein a thickness of the gap adjusting member is equal to a thickness of the color filter layer. The liquid crystal display of claim 1, wherein the transmission hole is positioned in a region corresponding to the reflective electrode. The method of claim 1, wherein the color filter layer, A color pixel expressing a predetermined color using the light and having the transmission hole; And And a black matrix surrounding the color pixels and blocking light leaked from the color pixels.

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