KR20020047801A - Liquid crystal display and manufacturing method of the same - Google Patents

Abstract

PURPOSE: A liquid crystal display and a method of fabricating the liquid crystal display are provided to form thin film transistors and colors filters on the same substrate so as to achieve high aperture ratio. CONSTITUTION: A liquid crystal display includes the first and second substrates, black matrix patterns(202) formed on the first substrate at a specific interval, and a color filter(203) formed between neighboring black matrix patterns. The liquid crystal display further includes an overcoat layer(204) formed on the overall surface of the substrate including the color filter, a gate line, a data line(205) and a thin film transistor formed on the overcoat layer. The liquid crystal display also has a passivation layer(206) formed on the overall surface of the substrate including the thin film transistor, a pixel electrode(207) formed on the passivation layer and superposed on a predetermined portion of the black matrix patterns, and liquid crystal filled between the first and second substrates.

Description

Liquid crystal display and manufacturing method of the same

The present invention relates to a display device, and more particularly, to a liquid crystal display device and a manufacturing method thereof.

Generally, backlight accounts for more than 60% of the power consumption of TFT-LCD modules in notebook monitors. To reduce this power consumption, the aperture ratio must be increased. Aperture Ratio refers to the ratio of the active contrast generation area to the total display area.It is the sum of the area contributing to the display and the black matrix in the ITO pixel electrode except for the portion not contributing to the display in the liquid crystal display panel. If the area excluding the pattern is divided by the total pixel area, the ratio becomes the effective transmission area contributing to the actual light transmission as the aperture ratio.

Factors affecting the aperture ratio include the thickness of the gate wiring and the data wiring, the distance between the pixel electrode and the data wiring or the gate wiring, the overlapping distance between the black matrix layer and the pixel electrode, the storage capacitance, and the area of the thin film transistor.

In order to realize a high opening rate, the size of the above elements should be reduced.

The data wiring is the open and mask alignment error of the data wiring, the gate wiring is the delay of the gate wiring, the gap between the pixel electrode and the data line is the mask alignment error, the short circuit of the two electrodes, and the liquid crystal Distinlination should be considered, and mask alignment error and parasitic capacitance should be considered for pixel electrode and gate wiring, and black matrix etch loss, bonding margin, and pixel electrode alignment error should be considered for black matrix layer and pixel electrode overlapping interval. In addition, the storage capacitance should raise the threshold voltage (Feed through) and the thin film transistor area should increase the charge rate.

Hereinafter, the structure of a liquid crystal display device according to the related art will be described in detail with reference to the accompanying drawings.

1 is a structural cross-sectional view of a liquid crystal display device according to the prior art.

As shown in FIG. 1, a lower plate on which a thin film transistor (not shown) is formed and an upper plate on which a color filter is formed, and a gate insulating film 102 is formed on an insulating substrate 101a. The data lines 103 are patterned on the gate insulating layer 102. Further, a silicon nitride protective film 104 is stacked on the entire surface of the substrate including the data line 103, and a pixel electrode 105 made of ITO is formed on the protective film 104 at regular intervals.

On the upper plate, a plurality of data lines, gate lines, and black matrix layers 106 formed in the lower plate on the insulating substrate 101b are patterned at regular intervals, and the black matrix layer is patterned. The color filter layers 107 of R, G, and B that implement color expression are formed in the spaces between the 106 and 106. It is also possible to form a planarization film 108 on the color filter layer 107 to protect and planarize the color filter layer. A common electrode 109 made of ITO is formed on the planarization layer.

However, the conventional liquid crystal display manufacturing method as described above has the following problems.

Since the black matrix pattern area must be designed in consideration of the margin of adhesion (more than 5 μm) of the color filter substrate and the thin film transistor substrate, which are the upper and lower plates, the opening ratio is reduced due to the black matrix pattern more than necessary.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a liquid crystal display device and a method of manufacturing the same, by forming a thin film transistor and a color filter on the same substrate to realize a high opening ratio.

1 is a structural cross-sectional view of a liquid crystal display device according to the prior art.

2 is a structural cross-sectional view of a liquid crystal display device according to the present invention;

3 is a graph showing a dark state transmittance according to an overlap length of a pixel electrode and a black matrix pattern.

4A through 4D are cross-sectional views illustrating a method of manufacturing a liquid crystal display device according to the present invention.

Explanation of symbols for the main parts of the drawings

201a, 201b: Insulating substrate 202: Black matrix pattern

203: color filter layer 204: overcoat

205: data line 206: protective film

207 pixel electrode 208 second black matrix

209: common electrode

The liquid crystal display device of the present invention for achieving the above object is formed in the space between the first substrate and the second substrate, the black matrix pattern formed on the first substrate at a predetermined interval, and the black matrix pattern A color filter layer, a planarization film formed on the color filter layer, a plurality of data lines, gate lines, and thin film transistors formed on the planarization film, and a substrate front including the data line, gate line, and thin film transistor. And a liquid crystal interposed between the first substrate and the second substrate, and a pixel electrode formed on the protective film so as to overlap a predetermined portion with the black matrix pattern. The manufacturing method includes preparing a first substrate and a second substrate, and forming a black matrix layer on the first substrate. Patterning the substrate, forming a color filter layer in a space between the black matrix layers, forming a planarization layer on the color filter layer, and patterning a plurality of data lines, gate lines, and thin film transistors on the planarization layer; Stacking a passivation layer on an entire surface of the substrate including the data line, the gate line, and the thin film transistor; forming a pixel electrode on the passivation layer to overlap a portion of the black matrix pattern; It is characterized by including interposing a liquid crystal in between.

On the other hand, a second black matrix layer is formed on the second substrate to prevent the transmission of light to the thin film transistor formed on the substrate.

Hereinafter, a liquid crystal display according to the present invention will be described in detail with reference to the accompanying drawings.

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

As shown in FIG. 2, a black matrix pattern 202 is formed on the insulating substrate 201a at regular intervals, and R for implementing color expression in a space between the black matrix patterns 202 is provided. A color filter layer 203 of G and B is formed, and a planarization film 204 is formed over the entire substrate including the color filter layer 203. In addition, a plurality of data lines 205, gate lines, and thin film transistors (not shown) are formed on the planarization layer 204 through a series of processes. A passivation layer 206 is formed on an entire surface of the substrate including the plurality of data lines, gate lines, and thin film transistors. An ITO pixel electrode 207 is formed on the passivation layer 206 so as to overlap a predetermined portion of the black matrix pattern.

On the upper plate, a second black matrix layer 208 is formed on the insulating substrate 201b, and a common electrode 209 made of ITO is formed on the entire surface of the substrate including the second black matrix layer 208.

On the other hand, one of the factors affecting the aperture ratio of the liquid crystal display device is the liquid crystal display (Disinclination). The foreground line refers to the boundary between the liquid crystal regions having opposite directors. In the end of the pixel electrode, the foreground is caused by the alignment and the electric field effect of the liquid crystal, thereby causing light leakage. In order to prevent the light leakage caused by the foreground, the pixel electrode and the black matrix pattern must overlap the predetermined portions d1 and d2.

In the liquid crystal display device according to the prior art, the overlapping portion of the pixel electrode and the black matrix pattern as described above needs to consider not only the disinclination but also the misalignment of the upper and lower plates. Thereby, there was a disadvantage that the opening ratio is lowered.

However, the liquid crystal display device according to the present invention does not need to consider the adhesion nonuniformity of the upper and lower plates because the thin film transistor is formed on the color filter layer. Accordingly, the overlapping portion of the pixel electrode and the black matrix pattern may be designed to have a thickness of about 1 μm in consideration of the above-described disinclination.

3 is a graph illustrating a dark state transmittance according to an overlap length between a pixel electrode and a black matrix pattern.

As shown in FIG. 3, when the overlap length between the pixel electrode and the black matrix pattern is 1 μm or less, the contrast decreases rapidly due to light leakage around the pixel electrode.

In the liquid crystal display according to the present invention, as shown in the graph, by applying the minimum overlap length of the pixel electrode and the black matrix pattern to prevent the disintegration, not only can the contrast be lowered but also the aperture ratio can be reduced. Improvement can be aimed at.

4A through 4D are cross-sectional views illustrating a method of manufacturing a liquid crystal display device according to the present invention.

As shown in FIG. 4A, a black matrix pattern 202 is formed of a black resin based material at a predetermined interval on the insulating substrate 201a, and color is expressed in a space between the black matrix patterns 202. To form the color filter layer 203 of R, G, B.

Subsequently, as shown in FIG. 4B, an overcoat 204 is formed on the entire surface of the substrate including the color filter layer 203 to form the thin film transistor and the protection of the color filter layer. The material of the planarization layer 204 may be any organic compound whose physical properties are hardened by Cure after spin coating such as BCB, HSQ, SSQ, MSSQ, POSS, and FO _x .

As shown in FIG. 4C, a plurality of data lines 205, gate lines, and thin film transistors (not shown) are formed on the planarization layer 204 in a series of processes. The series of processes refers to a process of forming a gate electrode, stacking a gate insulating film, forming a semiconductor layer, and forming a source / drain electrode in the case of a thin film transistor. The data line is a source / drain electrode, and the gate line is the same material and the same process as the gate electrode.

As shown in FIG. 4D, a protective film 206 is formed by stacking an insulating material such as silicon nitride over the entire surface of the substrate including the plurality of data lines 205, the gate lines, and a thin film transistor (not shown). The pixel electrode 207 is formed on the passivation layer 206 corresponding to the adjacent first black matrix. In this case, both ends of the pixel electrode 207 overlap the black matrix pattern with predetermined portions d1 and d2.

Subsequently, although not shown in the drawings, the substrate on which the color filter layer and the thin film transistor are formed and the substrate on which the other black matrix layer is formed to prevent light transmission to the thin film transistor (not shown) are opposed to the liquid crystal and then the liquid crystal is bonded. After forming, it is sealed and the manufacturing process of the liquid crystal display device which concerns on this invention is completed.

As described above, the liquid crystal display of the present invention and its manufacturing method have the following effects.

By forming the color filter layer and the thin film transistor together on one substrate, it is not necessary to design the black matrix layer in consideration of the adhesion nonuniformity, which was one of the problems of the conventional process, thereby significantly reducing the overlapping area between the pixel electrode and the black matrix and reducing the aperture ratio. Can improve.

Claims (6)

A first substrate and a second substrate; A black matrix pattern formed at a predetermined interval on the first substrate; A color filter layer formed in a space between the black matrix patterns; A planarization film formed on an entire surface of the substrate including the color filter layer; A gate line, a data line, and a thin film transistor formed on the planarization film; A protective film formed on the entire surface including the thin film transistor; A pixel electrode overlapping a predetermined portion of the black matrix pattern on the passivation layer; And a liquid crystal interposed between the first substrate and the second substrate. The liquid crystal display device according to claim 1, wherein the degree of overlap between the pixel electrode and the black matrix pattern has a range of 1 to 5 탆. The liquid crystal display device according to claim 1, further comprising another black matrix pattern on the second substrate to block the transmission of light to the thin film transistor. Preparing a first substrate and a second substrate; Forming a black matrix pattern at predetermined intervals on the first substrate; Forming a color filter layer in a space between the black matrix patterns; Forming a planarization film on the entire surface of the substrate including the color filter layer; Forming a data line, a gate line, and a thin film transistor on the planarization layer; Forming a protective film on an entire surface of the substrate including the thin film transistor; Forming a pixel electrode on the passivation layer to overlap a portion of the black matrix pattern; And interposing a liquid crystal between the first substrate and the second substrate. The method of claim 4, wherein the overlapping degree between the black matrix pattern and the pixel electrode is controlled in a range of 1 to 5 μm. 5. The method of claim 4, wherein the second substrate comprises the steps of forming another black matrix layer on the substrate to prevent transmission of light to the thin film transistor; And forming a common electrode on the black matrix layer.