KR100670053B1 - Liquid crystal displays - Google Patents

Abstract

The color filter is formed on the color filter board | substrate and board | substrate of a liquid crystal display device, and the overcoat film is formed on the color filter. A transparent common electrode having an opening is formed on the overcoat film, and a black matrix made of an opaque conductive material is formed on the common electrode. In this way, the sheet resistance of the common electrode can be reduced to reduce the distortion of the common electrode signal. In addition, since the common electrode may be formed of amorphous ITO, IZO, or the like, adhesion to the overcoat layer may be enhanced, and thus the shape of the opening may be precisely controlled.

Color filter, black matrix, common electrode, sheet resistance, liquid crystal display

Description

Liquid crystal display device {LIQUID CRYSTAL DISPLAYS}

1 is a cross-sectional view of a color filter substrate according to the prior art,

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 of a liquid crystal display according to a second exemplary embodiment of the present invention.

4 is a layout view of a liquid crystal display according to a third exemplary embodiment of the present invention.

FIG. 5 is a cross-sectional view taken along the line VV ′ of FIG. 4.

The present invention relates to a liquid crystal display device, and more particularly, to a color filter substrate for a liquid crystal display device.

In general, a liquid crystal display device injects a liquid crystal material between an upper substrate on which a common electrode, a color filter, and the like are formed, and a lower substrate on which a thin film transistor and a pixel electrode are formed. By applying a different potential to form an electric field to change the arrangement of the liquid crystal molecules, and through this to control the light transmittance is a device that represents the image.

Next, the structure of the color filter substrate according to the related art will be described with reference to the drawings.

  1 is a cross-sectional view of a color filter substrate for a liquid crystal display device according to the related art.

The black matrix 5 is formed on the board | substrate 1, and the color filter 2 of red, green, and blue is formed in the pixel area defined by the black matrix 5, respectively. An overcoat film 4 is formed on the color filter 2, and a common electrode 4 is formed on the overcoat film 4.

The color filter substrate of this structure is manufactured through the following process.

First, an opaque material is deposited on the substrate 1 and patterned to form a black matrix 5. Next, a tricolor filter 2 is formed between the black matrices 5 so that the periphery overlaps with the black matrices 5. The overcoat film 4 is laminated in order to compensate for the step caused by the color filter 2. Finally, a transparent conductive material is deposited to form a common electrode 4 on the overcoat film 4.

In the liquid crystal display device, a common potential must be applied to the common electrode 4 formed on the color filter substrate 1 through a connection point at the periphery of the common electrode 4. However, as the liquid crystal display becomes larger, the sheet resistance of the common electrode 4 increases, which is a problem. This is because when the sheet resistance of the common electrode 4 becomes large, distortion of the signal becomes severe. In particular, when openings are formed in the common electrode as a means for securing a wide viewing angle, the conductive passage of the common electrode is reduced by the area where the openings are formed, and this problem becomes more serious.

In addition, the common electrode 4 is formed of polycrystalline indium tin oxide (ITO) in order to reduce the sheet resistance of the common electrode 4 even slightly. The polycrystalline ITO has poor adhesion with the overcoat film 3. Therefore, the opening pattern is not precisely adjusted in the process of forming the opening in the common electrode 4. However, the shape of the opening pattern greatly affects the image quality.

The technical problem to be achieved by the present invention is to reduce the sheet resistance of the common electrode.

Another technical problem to be achieved by the present invention is to enable the opening of the common electrode to be precisely formed.

In order to solve this problem, in the present invention, the black matrix is formed of a conductive material and formed in contact with the common electrode.

Specifically, a color filter is formed on the first substrate, an overcoat film is formed on the color filter, and a common electrode having an opening pattern is formed on the overcoat film. A black matrix made of an opaque conductive material is formed in contact with the common electrode. The second substrate is opposed to the first substrate, a gate wiring for transmitting a scan signal is formed on the second substrate, and a data wiring for transferring an image signal is insulated from the gate wiring and formed on the second substrate. A pixel electrode having an opening is formed in a region corresponding to the color filter on the second substrate, and the thin film transfers or blocks the image signal transmitted through the data line to the pixel electrode according to the scan signal transmitted through the gate line. The transistor is formed on the second substrate.

At this time, the black matrix may be formed between the overcoat film and the common electrode. In addition, the gate wiring includes two lines connecting the main line and the two main lines, and when the liquid crystal display is viewed from the front, the gate wiring is preferably exposed along the periphery of the pixel region defined by the black matrix. Do. The common electrode may be formed of amorphous ITO or IZO.

Next, a structure of a liquid crystal display according to an exemplary embodiment of the present invention will be described with reference to the drawings.

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

The thin film transistor 11 and the pixel electrode 70 are formed on the lower substrate 10. More specifically, a gate line (not shown) formed in a horizontal direction is formed on the substrate 10, and a data line (not shown) formed in a cross direction and insulated from the gate line is formed. It is. An opening is formed in the pixel electrode 70 to secure a wide viewing angle.

The gate line transfers a scan signal to a gate electrode (not shown) of the thin film transistor 11, and the data line transfers an image signal to a source electrode (not shown) of the thin film transistor 11. The scan signal functions to transfer or block an image signal from a source electrode to a drain electrode (not shown) by forming or blocking a channel in a semiconductor layer (not shown) of the thin film transistor 11. The drain electrode is connected to the pixel electrode 70 so that the image signal is transmitted to the pixel electrode 70 through the drain electrode.

Red, green, and blue color filters 121 are formed on the transparent upper substrate 120, and an overcoat film 122 is formed on the color filters 121. A common electrode 123 made of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO) is formed on the overcoat layer 122, and Al or Cr, such as Al or Cr, is opaque on the common electrode 123. A black matrix 124 made of a conductive material is formed. In this case, the common electrode 123 is formed with an opening for securing a wide viewing angle by forming a fringe field together with the opening of the pixel electrode 70.

The liquid crystal material is injected between the upper substrate 120 and the lower substrate 10.

As such, when the black matrix 124 is formed of a conductive material and is in contact with the common electrode 123, the black matrix 124 also functions as a conductive path for transmitting a signal of the common electrode 123, thereby providing a common electrode 123. Can reduce the sheet resistance.

In addition, since the sheet resistance of the common electrode 123 is reduced, the common electrode 123 may be formed of amorphous ITO or IZO. Amorphous ITO and IZO have a somewhat higher resistance than polycrystalline ITO and the like, but have good adhesion with the overcoat film 122. Therefore, the opening part can be formed precisely.

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

The liquid crystal display according to the second embodiment is the same except that the positions of the liquid crystal display according to the first embodiment, the common electrode 123, and the black matrix 124 are reversed. That is, a black matrix 124 made of an opaque conductive material is formed on the overcoat layer 122, and a transparent common electrode 123 is formed on the black matrix 124 to cover the black matrix 124.

Through such a structure, the sheet resistance of the common electrode 123 can be reduced.

4 is a layout view of a liquid crystal display according to a third exemplary embodiment of the present invention, and FIG. 5 is a cross-sectional view taken along line VV ′ of FIG. 4.

First, two gate main lines 21 and 22 extend in the horizontal direction on the lower substrate 10, and connecting portions 23 and 24 connecting the two gate main lines 21 and 22 are formed. A gate insulating film 30 is formed on the gate wirings 21, 22, 23, and 24, and a semiconductor layer 40 is formed on the gate electrode 26 on the gate insulating film 30. A contact layer (not shown) is formed over 40). The data line 60 is formed in the vertical direction on the gate insulating film 30, and the source electrode 65 is formed in the form of a branch in the data line 60. The source electrode 65 extends over the contact layer and has a drain electrode 66 adjacent to the source electrode 65. A part of the drain electrode 66 which also faces the source electrode 65 is located on the contact layer. The protective film 80 is laminated on the data wires 60, 65, 66. In the passivation layer 80, a contact hole 81 exposing the drain electrode 66 is formed. The pixel electrode 70 is formed on the passivation layer 80 and connected to the drain electrode 66 through the contact hole 81. In this case, the pixel electrode 70 has a shape in which several corners having curved corners are connected.

The upper substrate 120 is formed in the same structure as the upper substrate of the liquid crystal display according to the first embodiment of the present invention. That is, the color filter 121, the overcoat film 122, the common electrode 123, and the black matrix 124 are sequentially formed on the substrate 120. At this time, the black matrix 124 and the gate wiring 21 are exposed to expose a portion of the gate wirings 21, 22, 23, and 24 of the lower substrate 10 along the periphery of the pixel region defined by the black matrix 124. , 22, 23, 24). The exposed widths of the gate lines 21, 22, 23, and 24 are larger than the alignment error of the upper and lower substrates.

In this case, since the black matrix 124 and the gate wirings 21, 22, 23, and 24 act together as a light blocking pattern, light leakage does not occur even if an alignment error occurs between the upper and lower substrates.

When the liquid crystal display device is manufactured as described above, distortion of the common electrode signal may be reduced by reducing the sheet resistance of the common electrode. In addition, since the common electrode may be formed of amorphous ITO, IZO, or the like, adhesion to the overcoat layer may be enhanced, and thus the shape of the opening may be precisely controlled.

Claims (4)

First substrate, A color filter formed on the first substrate, An overcoat film formed on the color filter, A common electrode formed on the overcoat layer and having an opening pattern; A black matrix formed on the common electrode to contact the common electrode and made of an opaque conductive material, A second substrate facing the first substrate, A gate wiring formed on the second substrate and transferring a scan signal; A data line formed on the second substrate and insulated from the gate line and transferring an image signal; A pixel electrode formed in a region corresponding to the color filter on the second substrate and having an opening forming a fringe field together with the opening pattern; A thin film transistor configured to transfer or block an image signal transmitted through the data line to the pixel electrode according to a scan signal transmitted through the gate line Liquid crystal display comprising a. First substrate, A color filter formed on the first substrate, An overcoat film formed on the color filter, A black matrix formed on the overcoat layer and made of an opaque conductive material, A common electrode connected to the black matrix on the black matrix and having an opening pattern, A second substrate facing the first substrate, A gate wiring formed on the second substrate and transferring a scan signal; A data line formed on the second substrate and insulated from the gate line and transferring an image signal; A pixel electrode formed in a region corresponding to the color filter on the second substrate and having an opening forming a fringe field together with the opening pattern; A thin film transistor which transfers or blocks an image signal transmitted through the data line to the pixel electrode according to a scan signal transmitted through the gate line Liquid crystal display comprising a. The method of claim 1 or 2, The gate wiring includes two lines connecting the main line and the two main lines, and when the liquid crystal display device is viewed from the front, the liquid crystal in which the gate wiring is exposed along the periphery of the pixel area defined by the black matrix. Display device. The method of claim 1 or 2, The common electrode is made of amorphous ITO or IZO.

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