KR20030018851A - Liquid crystal device - Google Patents

Abstract

PURPOSE: A liquid crystal display is provided to extend a contact area of an organic insulating layer and a seal line to improve adhesive strength of upper and lower substrates. CONSTITUTION: A liquid crystal display includes the first substrate(110) on which pixels are formed, the second substrate(270) facing the first substrate, and a liquid crystal layer(220) formed between the first and second substrates. The liquid crystal display further includes a pixel electrode(190) formed on the first substrate, and an organic insulating layer(180). The organic insulating layer has a surface structure including a plurality of first and second regions(182,184) having different heights for light scattering between the first substrate and the pixel electrode. The surface structure is extended to a seal line(210) used for attaching the first and second substrates to each other.

Description

Liquid crystal display

The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device that can improve the adhesion between the upper substrate and the lower substrate.

In today's information society, the role of electronic display devices becomes more and more important, and various electronic display devices are widely used in various industrial fields.

In general, an electronic display device refers to a device that transmits various information to a human through vision. In other words, an electronic display device may be defined as an electronic device that converts electrical information signals output from various electronic devices into optical information signals that can be recognized by human eyes, and serves as a bridge that connects humans and electronic devices. It may be defined as.

In such an electronic display device, when an optical information signal is displayed by a light emitting phenomenon, it is called an emissive display device, and when a light modulation is displayed by reflection, scattering, or interference phenomenon, a light receiving display ( It is called a non-emissive display device. The light emitting display device, also called an active display device, includes a cathode ray tube (CRT), a plasma display panel (PDP), a light emitting diode (LED), and an electroluminescent display (electroluminescent display). display; ELD). In addition, the light receiving display device, which is a passive display device, includes a liquid crystal display (LCD), an electrochemical display (ECD), an electrophoretic image display (EPID), and the like.

Cathode ray tubes (CRTs) used in image display devices such as televisions and computer monitors occupy the highest share in terms of display quality and economy, but have many disadvantages such as heavy weight, large volume and high power consumption. .

However, due to the rapid progress of semiconductor technology, the electronic display device suitable for the new environment, that is, the thin and light, the low driving voltage and the low power consumption of the electronic device, according to the miniaturization, low voltage and low power of various electronic devices, and the miniaturization and light weight of the electronic device, The demand for flat panel display devices with features is rapidly increasing.

Among the various flat panel display devices currently developed, liquid crystal displays are thinner and lighter than other display devices, have low power consumption and low driving voltage, and are widely used in various electronic devices because they can display images close to cathode ray tubes. Is being used.

The liquid crystal display device is composed of two substrates having electrodes formed thereon and a liquid crystal layer inserted therebetween, by applying a voltage to the electrodes to rearrange liquid crystal molecules of the liquid crystal layer to control the amount of transmitted light. Display device. Electrodes are formed on each of the two substrates, and a thin film transistor (TFT) for switching a voltage applied to each electrode is formed on one of the two substrates.

The liquid crystal display uses a transmissive liquid crystal display device that displays an image using a light source such as a backlight, a reflective liquid crystal display device using natural light, and a built-in light source of the display device itself in a dark place where an indoor or external light source does not exist. The display may be classified into a reflection-transmissive liquid crystal display device which operates in a transmissive display mode for displaying and operates in a reflective display mode for reflecting and displaying external incident light in an outdoor high-illuminance environment.

1 is a cross-sectional view showing a seal line region of a liquid crystal display according to a conventional method.

Referring to FIG. 1, a conventional liquid crystal display device includes a first substrate 20 on which pixels are formed, a second substrate 50 disposed to face the first substrate 20, and the first substrate 20. And a liquid crystal layer 40 formed between the second substrate 50.

The first substrate 20 includes a first insulating substrate 10 and a thin film transistor (not shown) of a switching element formed on the first insulating substrate 10. In addition, an organic insulating layer 15 is formed on the first insulating substrate 10 on which the thin film transistor is formed, and a pixel electrode (not shown) is formed on the organic insulating layer 15.

Between the first substrate 20 and the second substrate 50, a seal line 30 in the form of a spacer for adhesion between the upper and lower substrates is interposed between the first substrate 20 and the second substrate 50. A predetermined space is formed. The liquid crystal layer 40 is formed in the space between the first substrate 20 and the second substrate 50.

In the case of a conventional reflective or reflection-transmissive liquid crystal display device, the technique for improving the brightness is proceeding in a direction in which the reflection efficiency of the reflective pixel electrode is increased in combination with the ultra-opening ratio technique. As such, the organic insulating layer 15 has a surface structure including a plurality of first region portions 16 and second region portions 18 formed at relatively high levels in order to form fine irregularities in the reflective pixel electrode to improve reflection efficiency. Has Therefore, the reflective pixel electrode formed on the organic insulating layer 15 has the same shape as the surface of the organic insulating layer 15. The first region portions 16 are formed to have a shape of a groove having a relatively lower height than the second region portions 18, and the second region portions 18 have a shape of a protrusion having a relatively high height. It is formed so as to have a function as a micro lens.

In order to form such a surface structure on the organic insulating layer 15, an exposure and development process are involved. In this case, the exposure process is not performed in the seal line 30 region for adhesion between the upper and lower substrates. Therefore, the organic insulating layer 15 having the flat surface structure is positioned in the seal line 30 region. As a result, the contact area between the organic insulating layer 15 and the seal line 30 is reduced, and as a result, the adhesive force between the first substrate 20 and the second substrate 50 is lowered, resulting in deterioration of the reliability of the product.

In order to solve this problem, all of the organic insulating layers 15 in the seal line 30 region may be removed, but in this case, the first substrate 20 and the second substrate 50 are assembled by the seal line 30. When the assembly is performed, a problem may occur in which various lines connecting the gate pad unit and the data pad unit are opened.

Accordingly, an object of the present invention is to provide a liquid crystal display device capable of improving the adhesion between the upper substrate and the lower substrate.

1 is a cross-sectional view showing a seal line region of a liquid crystal display according to a conventional method.

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

3 is a cross-sectional view illustrating a seal line region of a liquid crystal display according to a second exemplary embodiment of the present invention.

<Explanation of symbols for main parts of the drawings>

100: first substrate 110: first insulating substrate

120 gate electrode 130 gate insulating film

140: active layer 150: ohmic contact layer

160 source electrode 170 drain electrode

180: organic insulating film 182: first region portion

184: second region portion 185: contact hole

190: pixel electrode 200: thin film transistor

210: seal line 220: liquid crystal layer

240: second alignment layer 250: common electrode

260 color filter 270 second insulating substrate

280: second substrate 300: uneven portion

In order to achieve the above object of the present invention, the present invention, the pixel substrate is formed; A second substrate formed to face the first substrate; A liquid crystal layer formed between the first substrate and the second substrate; A pixel electrode formed on the first substrate; And a surface structure including a plurality of first region portions and second region portions formed at a relatively high level for light scattering between the first substrate and the pixel electrode, wherein the surface structure includes the first substrate and the second substrate. The present invention provides a liquid crystal display device including an organic insulating layer formed to extend to a seal line region for adhering the adhesive.

According to the present invention, the organic insulating film and the seal line are formed by extending the first region portion and the second region portion in the seal line region for bonding the upper and lower substrates in the same manner as in the pixel region. Enlarge the contact area of the liver. Therefore, the adhesive force between a 1st board | substrate and a 2nd board | substrate can be improved.

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

2 is a cross-sectional view of a liquid crystal display device according to a first embodiment of the present invention, which shows a reflective liquid crystal display device.

Referring to FIG. 2, the reflective liquid crystal display according to the present exemplary embodiment includes a first substrate 100 on which pixels are formed, a second substrate 280 disposed opposite to the first substrate 100, and the first substrate 100. The liquid crystal layer 220 is formed between the first substrate 100 and the second substrate 280, and the pixel electrode 190 is formed between the first substrate 100 and the liquid crystal layer 220.

The first substrate 100 includes a first insulating substrate 110 and a thin film transistor 200 of a switching element formed on the first insulating substrate 110. The thin film transistor 200 includes a gate electrode 120, a gate insulating layer 130, an active layer 140, an ohmic contact layer 150, a source electrode 160, and a drain electrode 170.

The gate electrode 120 is formed by branching from a gate line (not shown) extending in a first direction on the first insulating substrate 110.

The gate insulating layer 130 is stacked on the entire surface of the first insulating substrate 110 on which the gate electrode 120 is formed, and the active layer 140 made of amorphous silicon is disposed on the gate insulating layer 130 at which the gate electrode 120 is disposed. ) And the ohmic contact layer 150 formed of doped amorphous silicon are sequentially formed. At this time, of course, the active layer 140 may be formed of polysilicon. In addition, the present embodiment describes a liquid crystal display device having a top-gate structure, but it is obvious that the present invention can be applied to a liquid crystal display device having a bottom-gate structure.

The source electrode 160 and the drain electrode 170 are formed on the ohmic contact layer 150 and the gate insulating layer 130 with respect to the gate electrode 120, respectively, to form the thin film transistor 200.

An organic insulating layer 180 made of a photosensitive material such as a resist is stacked on the first insulating substrate 110 on which the thin film transistor 200 is formed. The organic insulating layer 180 has a surface structure including a plurality of first region portions (grooves) 182 and second region portions (projections) 184 formed at a relatively high level for light scattering. In this case, the surface structure extends not only in the pixel region but also in the seal line 210 region for adhering the first substrate 100 and the second substrate 280 to each other. In the organic insulating layer 180, a contact hole 185 exposing a part of the drain electrode 170 of the thin film transistor 200 or, in some cases, the source electrode 160 is formed.

The pixel electrode 190 is formed on the contact hole 185 and the organic insulating layer 180. The pixel electrode 190 is connected to the drain electrode 170 through the contact hole 185 to electrically connect the thin film transistor 200 and the pixel electrode 190. In the case of a reflective liquid crystal display, the pixel electrode 190 is formed of a reflective conductive film having a high reflectance such as aluminum or silver. In the case of a transmissive liquid crystal display, the pixel electrode 190 is formed of indium-tin. -oxide) or indium-zinc-oxide (IZO). In the reflective-transmissive liquid crystal display device, the pixel electrode 190 is formed in a structure in which a transparent conductive film and a reflective conductive film are stacked.

A first orientation layer (not shown) is stacked on the pixel electrode 190.

The second substrate 280 facing the first substrate 100 includes a second insulating substrate 270, a color filter 260, a common electrode 250, and a second alignment layer 240.

The second insulating substrate 280 is made of the same material as the first insulating substrate 110, for example, glass or ceramic. The color filter 260 is disposed under the second insulating substrate 280, and the common electrode 250 and the second alignment layer 240 are sequentially formed under the color filter 260. The second alignment layer 240 functions to pretilt the liquid crystal molecules of the liquid crystal layer 220 together with the first alignment layer of the first substrate 100 at a predetermined angle.

Between the first substrate 100 and the second substrate 280 between the first substrate 100 and the second substrate 280 is interposed between the seal line 30 in the form of a spacer for adhesion between the upper substrate and the lower substrate A predetermined space is formed. The liquid crystal layer 220 is formed in the space between the first substrate 100 and the second substrate 280 to form the liquid crystal display device according to the present embodiment.

Hereinafter, a manufacturing method of the liquid crystal display shown in FIG. 2 will be described with reference to the drawings.

Referring to FIG. 2, after depositing a first metal film such as aluminum (Al), chromium (Cr), or molybdenum tungsten (MoW) on the first insulating substrate 110 made of an insulating material such as glass or ceramic, The first metal layer is patterned to form a gate line (not shown) and a gate electrode 120 branching from the gate line. Subsequently, silicon nitride is deposited on the entire surface of the first insulating substrate 110 including the gate electrode 120 by a plasma chemical vapor deposition (PECVD) method to form a gate insulating layer 130.

After the amorphous silicon film and the in-situ doped amorphous silicon film were sequentially deposited on the gate insulating film 130 by the plasma chemical vapor deposition method, the films were patterned and formed on the gate insulating film 130 above the gate electrode 120. The active layer 140 and the ohmic contact layer 150 are formed.

Subsequently, after depositing a second metal film such as chromium (Cr) on the entire surface of the resultant, the second metal film is patterned, and a data line (not shown) orthogonal to the gate line and a source branched from the data line. The electrode 160 and the drain electrode 170 are formed. Accordingly, the thin film transistor 200 including the gate electrode 120, the active layer 140, the ohmic contact layer 150, the source electrode 160, and the drain electrode 170 is completed. In this case, a gate insulating layer 130 is interposed between the gate line and the data line to prevent the gate line from contacting the data line.

Subsequently, a resist is coated on the entire surface of the first insulating substrate 110 on which the thin film transistor 200 is formed to have a thickness of about 1 to 3 μm by spin-coating to form an organic insulating layer 180 to form the first substrate 100. To complete). In this case, the organic insulating layer 180 is formed using, for example, an acrylic resin including a photo-active compound (PAC).

A first mask (not shown) for forming the contact hole 185 is disposed on the organic insulating layer 180, and then the drain electrode 170 is partially formed on the organic insulating layer 180 through an exposure and development process. A plurality of grooves are formed with the contact hole 185 exposed. The method of forming a plurality of grooves on the surface of the organic insulating layer 180 uses a partial exposure, a slit exposure, or a half-tone exposure method.

Specifically, in order to form the contact hole 185 in the organic insulating layer 180 made of resist, a first mask having a pattern corresponding to the contact hole 185 is positioned on the organic insulating layer 180. Subsequently, the organic insulating layer 180 on the drain electrode 170 is exposed by first performing a full exposure process using the first mask. Subsequently, in order to form the plurality of grooves 182 in the organic insulating layer 180, a second mask (not shown) for forming a microlens having a pattern corresponding to the groove is positioned on the organic insulating layer 180. Subsequently, the organic insulating layer 180 of the portion excluding the contact hole 185 is secondarily exposed through the lens exposure process using the second mask.

Next, through the development process, a contact hole 185 exposing the drain electrode 170 is formed in the organic insulating layer 180, and a plurality of grooves are formed on the surface of the organic insulating layer 180. That is, the surface of the organic insulating layer 180 may include first region portions 182 including a plurality of continuous grooves and second region portions 184 including a plurality of protrusions surrounded by the first region portions 182. Separated by.

In this case, the groove portions (first region portions) 182 extend in the seal line 210 region for bonding the first substrate 100 and the second substrate 280 to each other. Preferably, the first region portions 182 of the seal line 210 region are formed only by a predetermined thickness from the surface of the organic insulating layer 180.

As described above, after depositing a third metal film, for example, a reflective conductive film or a transparent conductive film or a metal film in which the reflective conductive film and the transparent conductive film are stacked on the organic insulating layer 180 on which the plurality of grooves are formed, the third metal is deposited. The film is patterned into a predetermined pixel shape to form the pixel electrode 190. Subsequently, a first alignment layer (not shown) is formed on the pixel electrode 190 to apply a resist and pretilt the liquid crystal molecules in the liquid crystal layer 220 at a selected angle through a rubbing process or the like.

Subsequently, the color filter 260, the common electrode 250, and the second alignment layer 240 are sequentially formed on the second insulating substrate 270 made of the same material as that of the first insulating substrate 110. The substrate 280 is completed. Subsequently, the second substrate 280 is disposed to face the first substrate 100, and then bonded between the first substrate 100 and the second substrate 280 via a seal line 210 in the form of a spacer. In addition, a predetermined space is formed between the first substrate 100 and the second substrate 280. Thereafter, the liquid crystal layer 220 is formed by injecting a liquid crystal material into the space between the first substrate 100 and the second substrate 280 using a vacuum injection method, thereby completing the liquid crystal display device according to the present embodiment. do.

3 is a cross-sectional view illustrating a seal line region of a liquid crystal display according to a second exemplary embodiment of the present invention.

Referring to FIG. 3, the surface structure of the organic insulating layer 180 is formed over the entire thickness of the organic insulating layer 180 in the seal line 210 region interposed between the first substrate 100 and the second substrate 280. It includes the first region portion 300 of the porous shape. Preferably, the porous first region portions 300 are formed at portions where no wiring is present. That is, the first region portions 300 having a porous shape may be formed by completely exposing the portions having no wiring.

In addition, although not shown, the first region portions formed in the seal line 210 region may have a first shape formed only by a predetermined thickness from the surface of the organic insulating layer 180, and may be formed in the entire thickness of the organic insulating layer 180. The second shape may have a combined structure.

As described above, according to the present invention, the organic insulating film is formed by forming the surface structure of the organic insulating film so that the first region portion and the second region portion extend in the seal line region for bonding the upper and lower substrates in the same manner as in the pixel region. The contact area between the seal and the seal line is enlarged. Therefore, the adhesive force between a 1st board | substrate and a 2nd board | substrate can be improved.

As described above, although described with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and modified within the scope of the present invention without departing from the spirit and scope of the present invention described in the claims below. It will be appreciated that it can be changed.

Claims (5)

A first substrate on which pixels are formed; A second substrate formed to face the first substrate; A liquid crystal layer formed between the first substrate and the second substrate; A pixel electrode formed on the first substrate; And And a surface structure including a plurality of first region portions and second region portions formed at a relatively high level for light scattering between the first substrate and the pixel electrode, wherein the surface structure comprises the first substrate and the second substrate. A liquid crystal display device comprising an organic insulating film formed to extend to a seal line region for bonding. The method of claim 1, wherein the first region has a groove shape having a relatively lower height than the second region portions, and the second region has a plurality of protrusion shapes having a relatively high height. LCD display device. The liquid crystal display of claim 1, wherein the first region formed in the seal line region is formed only by a predetermined thickness from a surface of the organic insulating layer. The liquid crystal display of claim 1, wherein the first region formed in the seal line region is formed over the entire thickness of the organic insulating layer. The method of claim 1, wherein the first region formed in the seal line region has a structure in which a first shape formed only by a predetermined thickness from a surface of the organic insulating film and a second shape formed in the entire thickness of the organic insulating film are combined. A liquid crystal display device.