KR20030049988A - Liquid crystal display, array panel having a reflector and manufacturing method thereof - Google Patents

Abstract

PURPOSE: A liquid crystal display having a reflective plate, an array substrate and a method for fabricating the array substrate are provided to form a color filter on the array substrate to improve aperture rate. CONSTITUTION: A liquid crystal display includes the first substrate(110), gate lines and data lines formed on the first substrate to define pixel regions, a gate insulating layer(130) covering the gate lines, a thin film transistor connected to each gate line and each data line, and a passivation layer covering the thin film transistor. The liquid crystal display further includes a reflective plate(181) formed on the pixel region placed on the gate insulating layer, a color filter(140) formed on the reflective plate, a pixel electrode(200) formed on the color filter and made of a transparent conductive material connected to the thin film transistor, the second substrate facing the first substrate, a transparent common electrode(50) formed on the second substrate, and a liquid crystal layer formed between the pixel electrode and the common electrode.

Description

Liquid crystal display, array substrate having reflector and manufacturing method therefor {Liquid crystal display, array panel having a reflector and manufacturing method}

The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device having an reflective plate, an array substrate, and a manufacturing method thereof.

In general, liquid crystal displays inject liquid crystal materials between upper and lower substrates on which opposing field-forming electrodes are formed, and then apply voltages to the two electrodes to form liquid crystal molecules. It is a device that expresses an image by adjusting the transmittance of light by moving.

The liquid crystal display may be classified into a transmission type and a reflection type according to a light source to be used.

Transmissive liquid crystal display is a form of displaying an image by adjusting the amount of light according to the arrangement of the liquid crystal by injecting artificial light from the backlight (backlight) attached to the back of the liquid crystal panel to the liquid crystal The device adjusts light transmittance according to the arrangement of liquid crystals by reflecting external natural or artificial light.

The transmissive liquid crystal display uses an artificial back light source, so that bright images can be realized even in a dark environment. However, the power consumption of the transmissive liquid crystal display is large. Since the structure is dependent on the power consumption is less than the transmissive liquid crystal display device, but can not be used in a dark place has the disadvantage.

Accordingly, a liquid crystal display device having both a reflection and a transmission has been proposed as a device capable of appropriately selecting and using two modes according to a necessary situation. Both the reflective and transflective liquid crystal display devices have reflectors for reflecting external light.

Hereinafter, a transflective liquid crystal display device will be described as an example of a liquid crystal display device having a reflection plate with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view illustrating a concept of a general transflective liquid crystal display, and includes a pixel electrode 20 on a lower substrate 10 including a thin film transistor (not shown) that is a switching element. Is formed. The pixel electrode 20 is composed of two parts, the transmissive electrode 21 and the reflective electrode 22. The reflective electrode 22 has a hole formed therein, and the hole of the reflective electrode 22 The transmissive electrode 21 is formed. The transmission electrode 21 is made of a transparent conductive material having a relatively high light transmittance, such as indium-tin-oxide (ITO) or indium-zinc-oxide (IZO). The reflective electrode 22 is made of a material having a low resistance and a high reflectance, such as aluminum (Al).

The upper substrate 30 is disposed to face the lower substrate 10 in parallel with the lower substrate 10 at a predetermined distance, and the inner surface of the upper substrate 30 is colored at a position corresponding to the pixel electrode 20. A color filter 40 is formed. The color filter 40 includes three colors of red, green, and blue, and a color filter having one color corresponds to one pixel electrode 20. A common electrode 50 formed of a transparent conductive material similar to the material of the pixel electrode is formed under the color filter 40. Although not shown, a black matrix is positioned between each color filter 40 of the upper substrate 30 to prevent light leakage from an area other than the pixel, and to distinguish colors of the color filter 40. do.

Next, the liquid crystal layer 60 is positioned between the common electrode 50 of the upper substrate 30 and the pixel electrode 20 of the lower substrate 10.

Outside of the two substrates 10 and 30, first and second retardation films 71 and 72 are disposed, respectively. The first and second retardation plates 71 and 72 are polarized light. It changes the state. Here, the first and second retardation plates 71 and 72 have a phase difference corresponding to λ / 4 (λ = 550 nm) (quarter wave plate; QWP), and the incident linear flat light is converted into circularly polarized light. , Change the circularly polarized light into linearly polarized light.

The lower polarizing plate 81 and the upper polarizing plate 82 are disposed outside the first and second retardation plates 71 and 72, respectively. Here, the light transmission axis of the upper polarizing plate 82 has an angle of 90 degrees with respect to the light transmission axis of the lower polarizing plate 81.

In addition, the backlight 90 is disposed outside the lower polarizer 81, that is, below the lower polarizer 81, and thus is used as a light source in the transmission mode.

On the other hand, the transflective liquid crystal display device is a process of manufacturing a lower array substrate in which a thin film transistor and a pixel electrode are arranged like a general transmissive liquid crystal display device and a process of manufacturing an upper color filter substrate including a color filter and a common electrode. And a liquid crystal cell process consisting of the arrangement of the two substrates prepared, the injection and encapsulation of the liquid crystal material, and the attachment of the polarizing plate.

FIG. 2 is a plan view of an array substrate of a specific transflective liquid crystal display device having the same concept as that of FIG. 1, and FIG. 3 is a cross-sectional view illustrating an upper substrate corresponding to a schematic cross section taken along a line III-III of FIG. 2. . The same or similar parts as in Fig. 1 in the reference numerals are given the same and similar numbers.

A gate line 121 and a data line (date line) 161 intersect the lower plate to define a pixel area, and a gate electrode 122 and a source are located near the intersection area of the two lines 121 and 161. A thin film transistor including a source electrode 162, a drain electrode 163, and a semiconductor layer 141 is positioned.

The drain electrode 163 is in contact with the pixel electrode 200 through a contact hole 171, and a reflecting plate (181 of FIG. 3) having a hole 183 is disposed under the pixel electrode.

The conventional method of forming an array substrate forms a gate line 121 including a gate electrode 122 on the substrate 10. The gate line 121 may be formed of one layer or two laminated metal layers in consideration of conductivity.

A gate insulating layer 124 is formed on the gate line 121, and an island-shaped semiconductor layer 141 is formed. A metal layer is deposited and patterned on the semiconductor layer 141 to form a data line 161 having a source electrode 162, a drain electrode 163, and a reflecting plate 181. The reflective plate 181 may be formed at the same time as the gate electrode 121 is formed.

Next, a transparent organic insulating layer such as benzocyclobutene (BCB) is deposited and patterned to form a contact hole 171, and then a transparent conductive metal is deposited to form the contact hole 171 through the drain electrode 163. ) Is formed to contact the pixel electrode 200.

The upper substrate is similar to the conventional transmissive color filter substrate by forming the black matrix 45 and the color filter 40 on the substrate 30 and then forming the common electrode 50 with the transparent conductive metal layer. .

By the way, in the transflective liquid crystal display device having such a structure, as shown in FIG. 3, it can be seen that the color of the corresponding color filter 40 is displayed when viewed in the I direction. As the angle between and decreases, the light path is reflected and directed toward the black matrix 45 or the adjacent color filter layer 40.

Accordingly, there is a problem that the desired color is not expressed, the luminance is degraded, or color shift occurs.

This problem may also be caused by a mis-alignment problem in the assembly process of the upper and lower plates, and this problem is also applied to a reflective liquid crystal display device using only an external light source.

The present invention has been made to solve the problems of the prior art as described above, an object of the present invention is to provide a liquid crystal display device having a reflective electrode that can reduce the color shift phenomenon and a manufacturing method thereof.

Other advantages of the present invention will be understood through the embodiments described later.

1 is a cross-sectional view of a general transflective liquid crystal display device.

2 is a plan view of an array substrate of a general transflective liquid crystal display device;

3 is a cross-sectional view simultaneously taken along the line III-III of FIG. 2 and an upper substrate corresponding thereto.

4 is a plan view of an array substrate of a transflective liquid crystal display according to the present invention.

FIG. 5 is a cross-sectional view simultaneously illustrating a cross section taken along the line VV of FIG. 4 and an upper substrate corresponding thereto. FIG.

FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 4 and an upper substrate corresponding thereto at the same time. FIG.

* Brief description of symbols for the main parts of the drawings *

110: lower substrate 181: reflector

140: color filter 145: black matrix

200: pixel electrode 50: common electrode

In order to achieve the above object, the present invention has a basic spirit to provide an array substrate having a color filter layer formed on a reflecting plate.

A black matrix is positioned between each color filter layer. Preferably, the black matrix is an organic insulating film in which a pigment capable of blocking light is mixed.

There is no color filter layer on the top plate corresponding to the array substrate, and only the common electrode is formed.

According to one aspect of the invention, the transparent substrate; A gate electrode disposed on the transparent substrate; A gate insulating layer on the gate electrode; An active layer on the gate insulating layer, wherein the active layer is located above the gate electrode; Source and drain electrodes disposed on the active layer; A reflection plate positioned in the pixel region on the gate insulating layer; A color filter on the reflection plate; A black matrix in contact with the color filter and positioned above the active layer; The present invention provides an array substrate for a liquid crystal display device including a transparent electrode connected to the drain electrode and positioned above the color filter layer.

According to another aspect of the invention, a substrate having a first region and a second region; A switching element located on said first region; A reflection plate located on the second area; A black matrix on the switching element; A color filter positioned on the reflector; An array substrate for a liquid crystal display device including a transparent electrode connected to the switching element is provided on the color filter of the second region.

According to another aspect of the invention, forming a gate electrode on the substrate; Forming a gate insulating layer on the gate electrode; Forming an active layer on the gate insulating layer; Depositing and patterning a metal layer on the active layer to form a source electrode, a drain electrode, and a reflecting plate; forming a black matrix on the active layer and the drain electrode; Forming a color filter adjacent to the black matrix on the reflecting plate; It provides a method for manufacturing an array substrate for a liquid crystal display device comprising the step of forming a transparent electrode on the color filter in contact with the drain electrode.

According to another aspect of the invention, forming a switching device in the first region of the substrate; Forming a reflecting plate in a second region of the substrate; Forming a black matrix on the switching element; Forming a color filter on the reflecting plate; It provides an array substrate manufacturing method for a liquid crystal display device comprising the step of forming a transparent electrode connected to the switching element on the color filter.

The black matrix is an organic insulating film, preferably benzocyclobutene (BCB) or photosensitive acryl series.

When openings are formed in each of the reflecting plates, the reflecting plate may be used as an array substrate for a transflective liquid crystal display device.

Hereinafter, a transflective liquid crystal display and a manufacturing method thereof according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

4 is a plan view of an array substrate of a transflective liquid crystal display device as an example of a liquid crystal display device having a reflective plate according to the present invention, and FIG. 5 is a cross-sectional view taken along the line VV of FIG. 4. 4 is a plan view similar to that of FIG. 2, but a black matrix 145 is formed to cover the data line 161, the gate line 121, and the thin film transistor T, and a color is formed between the black matrix 145. It can be seen that the location where the filter 140 is located is different.

As can be clearly seen in FIG. 5, in the array substrate 300 according to the present invention, the color filter layer 140 is positioned on the reflecting plate 181, and each color filter layer 140 or each pixel region is divided into a thin film. The black matrix 145 which blocks light to the transistor covers the thin film transistor, the gate wiring, and the data wiring along the edge of each color filter layer 140.

Referring to FIG. 5, a method of manufacturing an array substrate according to an exemplary embodiment of the present invention will be described. First, a normal cleaning operation is performed on a substrate 110, a buffer layer (not shown) is formed, and then gate wiring (FIG. A gate electrode 122 connected integrally with 121 of 4 is formed.

In this case, the gate electrode 122 may be formed of a double metal layer using chromium, copper, aluminum, or the like.

The gate insulating layer 130 is formed of an insulating layer such as a silicon nitride film (SiN _x ) or a silicon oxide film (SiO ₂ ) over the entire surface of the substrate on the gate electrode 122.

Thereafter, the semiconductor layer is deposited and patterned to form an island-shaped active layer 141, and dopants such as boron (B) and phosphorus (P) are doped to form ohmic contact layers 151 and 152. ).

Subsequently, a source electrode 162 connected to the data wiring (161 of FIG. 4) and a drain electrode 163 spaced apart from the data wiring (161 of FIG. 4) are formed of a metal having excellent reflection characteristics such as aluminum or aluminum alloy, and an opening 183 is formed in the pixel region. The reflection plate 181 is formed. The reflective plate 181 may be formed using a material having excellent reflection characteristics rather than metal using a separate mask. The opening 183 is used to pass the light incident from the light distribution device (not shown) from the bottom of the substrate 110 and is used in the transmissive mode. Accordingly, the reflective plate 181 of the reflective liquid crystal display device has no opening 183.

As another example, when the gate insulating layer 130 is a transparent insulating layer, the reflective plate 181 may be formed at the same time when the gate wiring 121 is formed.

Subsequently, a black matrix 145 is formed by depositing and patterning an organic insulating layer of benzocyclobutene (BCB) or photosensitive acrylic series. At this time In order to use the organic insulating layer as the black matrix 145, an organic pigment (orgonic pigment) of black color is added.

Preferred examples of the organic pigment include, for example, phthalo cyanine pigments such as phthalo cyanine blue and phthalo cyanine green; Anthraquinone pigments such as chromophthal red; Azo or azo-lake pigments such as Bordeaux 10B and lake red; Iso indolinone pigments such as Irazine yellow; Dioxane pigments such as dioxane violet; Nitroso pigments such as naphthol green B; Nitro pigments; Lake pigments such as peacock blue lake and rodanine lake; Quinacridone pigments; Pigments with high heat resistance and high fastness, such as quinacridine pigments, are included.

As illustrated in FIG. 4, the black matrix 145 covers the gate wiring 121, the data wiring 161, and the thin film transistor T.

Thereafter, the color filter layer is deposited and patterned to form the color filter 140 in the pixel region surrounded by the black matrix 145. The color filter 140 is composed of red, green, and blue colors, and one color is located in one pixel area.

Thereafter, the black matrix 145 is patterned to form a contact hole 171, and a pixel electrode 200 made of a transparent conductive material such as ITO or IZO is formed in the pixel area on the color filter 140.

FIG. 6 is a cross-sectional view simultaneously showing a cross section of the array substrate according to line VI-VI of FIG. 4 and an upper substrate bonded thereto correspondingly.

Since the color filter 140 is formed on the lower substrate 110, there is no color filter on the upper substrate 30, and only the common electrode 50 made of a transparent conductive material such as ITO or IZO is formed. Thereafter, the upper and lower substrates are bonded to each other, and then the liquid crystal 400 is injected to complete the liquid crystal display.

Looking at the path of the external light in the liquid crystal display having such a structure, not only the external light that enters substantially perpendicularly to the reflecting plate 181, but also the external light incident almost in parallel to the upper substrate 30 is reflected. Since the color of the color filter reflected at 181 does not change, color shift may be reduced or eliminated.

As described above, the embodiments described above can be applied to the reflective liquid crystal display device as it is.

As described above, the liquid crystal display device having the reflecting plate according to the present invention has a structure in which a color filter is stacked on the reflecting plate, thereby reducing or eliminating color shift due to a change in viewing angle.

Furthermore, since mis-alignment that may occur between the pixel electrode and the color filter, which occurs when the color filter is formed on the top plate, can be prevented, the color shift phenomenon can be further reduced.

Claims (14)

A first substrate; A gate line and a data line formed on the first substrate and crossing each other to define a pixel area; A gate insulating film covering the gate wiring; A thin film transistor connected to the gate line and the data line; A protective layer covering the thin film transistor; A reflection plate positioned in the pixel area above the gate insulating layer; A color filter formed on the reflective plate; A pixel electrode formed on the color filter and made of a transparent conductive material connected to the thin film transistor; A second substrate spaced apart from and opposed to the first substrate; A transparent common electrode formed on an opposite surface of the second substrate; A liquid crystal layer injected between the pixel electrode and the common electrode Liquid crystal display comprising a. The method of claim 1, The protective layer is made of an organic insulating material. The method of claim 1, The protective layer is a liquid crystal display of black pigment mixed. The method of claim 1, The protective layer is BCB or acrylic liquid crystal display device. A transparent substrate having a pixel region; A gate electrode disposed on the transparent substrate; A gate insulating layer on the gate electrode; An active layer on the gate insulating layer, wherein the active layer is located above the gate electrode; Source and drain electrodes disposed on the active layer; A reflection plate positioned in the pixel region on the gate insulating layer; A color filter on the reflection plate; A black matrix surrounding the color filter and positioned above the active layer; A transparent electrode connected to the drain electrode and positioned on the color filter layer; Array substrate for a liquid crystal display device comprising a. A substrate having a first region and a second region; A switching element located on said first region; A reflection plate located on the second area; A black matrix on the switching element; A color filter positioned on the reflector; A transparent electrode connected to the switching element on the color filter of the second region; Array substrate for a liquid crystal display device comprising a. The method according to any one of claims 5 and 6, The black matrix is an array substrate, an organic insulating film mixed with black pigment. The method according to any one of claims 5 and 6, And the pixel electrode is connected to the drain electrode through a contact hole formed in the black matrix. Forming a gate line and a data line intersecting the first substrate to define a pixel area; Forming a thin film transistor connected to the gate line and the data line; Forming a reflector on the pixel region of the substrate; Forming a protective layer covering the thin film transistor; Forming a color filter on the reflective plate; Forming a pixel electrode connected to the thin film transistor and formed of a transparent conductive material on the color filter; Forming a transparent common electrode on the second substrate; Opposing a first substrate on which the pixel electrode is formed and a second substrate on which the common electrode is formed; Forming a liquid crystal layer between the opposite pixel electrode and the common electrode Method of manufacturing a liquid crystal display comprising a. Forming a gate electrode on the substrate; Forming a gate insulating layer on the gate electrode; Forming an active layer on the gate insulating layer; Depositing and patterning a metal layer on the active layer to form a source electrode, a drain electrode, and a reflector; Forming an insulating black matrix on the active layer and the drain electrode; Forming a color filter adjacent to the black matrix on the reflecting plate; Forming a transparent electrode on the color filter in contact with the drain electrode Array substrate manufacturing method for a liquid crystal display device comprising a Forming a switching device in the first region of the substrate; Forming a reflecting plate in a second region of the substrate; Forming an insulating black matrix on the switching element; Forming a color filter on the reflecting plate; Forming a transparent electrode connected to the switching element on the color filter Array substrate manufacturing method for a liquid crystal display device comprising a. The method according to any one of claims 10 and 11, The black matrix is an array substrate manufacturing method of an organic insulating film mixed with black pigment The method of claim 12, The organic insulating film is a benzocyclobutene (BCB) or photosensitive acrylic array method of manufacturing an array substrate The method of claim 11, And forming a contact hole in the black matrix to connect the pixel electrode to the switching element.