KR100601162B1 - Liquid crystal display - Google Patents

Abstract

On the color filter substrate, a red (R), green (G), and blue (B) color filter is formed on the transparent insulating substrate, and a common electrode made of ITO is opposed to the pixel electrode of the thin film transistor substrate. It is formed on the front of the substrate. Further, on the common electrode, a projection pattern made of a black photosensitive resistor is formed in a shape having a square opening of a minute region. The protrusion pattern is formed of a unit pixel in which red, green, and blue color filters are formed, and has a function of a black matrix that absorbs light leaking between the unit pixels.

Description

Liquid crystal display

The present invention relates to a liquid crystal display device, and more particularly, to a vertically aligned liquid crystal display device in which liquid crystal molecules are vertically aligned with respect to a substrate.

In general, a liquid crystal display device has a structure in which a liquid crystal is injected between two substrates, and the amount of light transmitted is controlled by adjusting the intensity of the electric field applied thereto.

A vertically aligned twisted nematic (VATN) type liquid crystal display includes a pair of transparent substrates having transparent electrodes formed on an inner surface thereof, a liquid crystal material between two transparent substrates, and an outer surface of each transparent substrate. It consists of two polarizers attached to and polarizing light. In the state in which the electric field is not applied, the liquid crystal molecules are vertically oriented with respect to the two substrates, and when the electric field is applied, the liquid crystal molecules filled between the two substrates are parallel to the substrate and twisted in a spiral with a constant pitch.

In the case of the VATN liquid crystal display, the liquid crystal molecules are vertically aligned with respect to the substrate in the state in which no electric field is applied, and thus, when a polarizing plate is used, the light may be completely blocked in the state in which the electric field is not applied. That is, since the luminance of the off state is very low in the normally black mode, a high contrast ratio may be obtained as compared with a conventional twisted nematic liquid crystal display. However, in the state where an electric field is applied, especially when a gradation voltage is applied, as in the normal twisted nematic mode, a large difference in retardation of light due to the birefringence effect occurs depending on the viewing direction of the liquid crystal display, resulting in a narrow viewing angle. The problem is losing. In order to solve this problem, a method of forming a multi-region by forming a pattern on a transparent electrode to induce a fringe field of the electric field or forming a projection pattern in FUJITSU, has been proposed to divide and orient the liquid crystal material.

However, the projection pattern used by FUJITSU Corporation is formed by leaving the photoresist, which is transmitted through some red light or formed into a half-moon-shaped cross-sectional structure to increase the brightness of the off state to reduce the contrast ratio. Acts as. That is, the liquid crystal molecules oriented on the half-moon-shaped projection pattern are not completely vertically aligned without an electric field applied, and light leakage occurs. In addition, an additional photographic process is required to form protrusions or transparent electrode patterns.

SUMMARY OF THE INVENTION An object of the present invention is to solve such a problem, and to implement a liquid crystal display device having a high contrast ratio by blocking light leakage.

Another object of the present invention is to simplify the manufacturing process of the liquid crystal display device.

In order to solve the above problems, in the liquid crystal display according to the present invention, a projection pattern for dividing and aligning the liquid crystal molecules is formed of a black photosensitive resist that absorbs all light.

Here, the projection pattern may be used as a black matrix.

In this case, the black matrix may be formed on a thin film transistor substrate for a liquid crystal display device in which a thin film transistor is formed, or may be formed on a color filter substrate on which red, green, and blue color filters are formed.

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

In an embodiment of the present invention, the projection pattern is composed of a photosensitive resist of a color of a gum, and the projection pattern has a function of a black matrix while simultaneously aligning and dividing the liquid crystal molecules. At this time, the projection pattern having the function of the black matrix may be formed on the thin film transistor substrate, or may be formed on the color filter substrate.

First, the case where the projection pattern having the function of the black matrix is formed on the color filter substrate will be described in detail with reference to FIGS. 1A and 1B.

1A and 1B are layout views illustrating structures of a thin film transistor substrate for a vertical alignment liquid crystal display device and a color filter substrate for a liquid crystal display device according to a first embodiment of the present invention, respectively.

As shown in FIG. 1A, the thin film transistor substrate includes a gate line 20 that transmits a scan signal from the outside in a horizontal direction on a transparent insulating substrate, and a portion of the gate line 20 is wider than other portions. It has a protruding portion 22. A portion of the gate line 20 becomes the gate electrode 21, and the channel layer 40 of the thin film transistor formed on the gate electrode 21 is insulated from the gate electrode 21. In the vertical direction, a data line 60 for transmitting an image signal from an external source is formed, insulated from and intersected with the gate lines 20 and 21, and a source electrode 61 and a gate electrode connected to the data line 60. The drain electrode 62 is formed on the opposite side of the source electrode 61. A pixel electrode 80 connected to the drain electrode 62 is formed in the pixel region defined by the intersection of the gate lines 20 and 21 and the data line 60, and the pixel electrode 80 is formed by a gate. It overlaps with the protrusion 22 of the line 20 to form a holding capacitance. On the pixel electrode 80, a projection pattern 110 formed of a black photosensitive resistor is formed in a shape in which three crosses formed in a horizontal and a vertical direction are connected to each other.

On the other hand, as shown in Figure 1b, the color filter substrate is formed on the transparent insulating substrate, although not shown in the drawings, red (R), green (G), blue (B) color filter is formed in a pixel unit, A common electrode made of ITO is formed to face the pixel electrode 80 of the transistor substrate. In addition, on the common electrode, a protrusion pattern 120 formed of a black photosensitive resistor is formed in a shape having a square opening defining three microregions. The protrusion pattern 120 has a function of a black matrix that absorbs light leaking between unit pixels in which red, green, and blue color filters are formed.

Next, the case where the projection pattern having the function of the black matrix is formed on the thin film transistor substrate will be described in detail.

2A and 2B are layout views illustrating a thin film transistor substrate and a color filter substrate for a liquid crystal display according to a second exemplary embodiment of the present invention, respectively.

As shown in Figs. 2A and 2B, the structure is similar to that of the first embodiment of the thin film transistor substrate and the color filter substrate.

The difference is that the projection pattern 120 having a function of a black matrix that absorbs light leaking between the unit pixels is formed on the pixel electrode 80 formed in the unit pixel of the thin film transistor substrate, and the projection pattern 120 is formed. ) Defines a box-shaped minute region 121. In addition, a cross-shaped protrusion pattern 110 is formed on the color filter substrate.

In the first and second embodiments of the present invention, the projection patterns 110 and 120 for divisional orientation have a cross shape or a square shape, but may have various shapes along the divisional orientation, and the projection pattern 110 may have an aperture ratio. It is desirable to form a thin width in consideration, and may be varied.

Here, the polarizing plate may be further attached to the outside of the two substrates and the polarization axes are perpendicular to each other.

In the liquid crystal display according to the first and second embodiments of the present invention, the shapes of the liquid crystal molecules partially aligned are as follows.

3 is a plan view illustrating one pixel of the vertically aligned liquid crystal display according to the first exemplary embodiment of the present invention. In FIG. 3, only the projection pattern for the split orientation is shown.

First, the portion indicated by the thick solid line represents the protrusion 110 formed in the thin film transistor substrate in the first embodiment, and the hatched portion represents the protrusion 120 formed in the color filter substrate in the first embodiment.

In the case of the liquid crystal display device having the protrusion patterns 110 and 120, the liquid crystal molecules 30 may be formed in each of the minute regions defined by the protrusions 110 and 120 formed on the two substrates, as shown in FIG. 3. 121) The projections formed on one of the square substrates are arranged in a diagonal direction from the bent portion to the bent portions formed on the other substrate, and the alignment direction of the liquid crystal directors in the adjacent area is 90 degrees.

Next, the protrusion pattern formed on the liquid crystal display according to the exemplary embodiment of the present invention will be described in detail.

4 is a cross-sectional view of the linear projection pattern.

As shown in FIG. 4, the cross section of the projection pattern 110 formed on the transparent electrode 80 made of ITO, which is a transparent conductive material, on the substrate 100 is not a sawtooth shape but a pressed half moon shape. Here, when the width of the projection pattern 110 is reduced to reduce the area occupied by the projection pattern 110 and improve the aperture ratio, the cross section of the projection pattern 110 becomes more half-moon-shaped. However, since the projection pattern 110 used in the present invention uses a black photosensitive resist used for the organic black matrix, the projection pattern 110 absorbs light so that light does not leak in the off state of normally black mode. Therefore, the brightness is not increased in the off state, so the contrast ratio is improved.

Further, in the manufacturing process of the liquid crystal display device, since the projection pattern 120 made of the black photosensitive resist in the first and second embodiments has a function of a black matrix, a separate black matrix manufacturing process can be omitted. The manufacturing process can be simplified.

In addition, the black photosensitive resist has a light shielding property of 3.5 or more, and removes red, green, and blue mixed color to increase the sharpness of the display light, and also absorbs the light incident on the semiconductor layer 40 to prevent leakage of the thin film transistor. Can be blocked.

In one embodiment, the black photosensitive resist having this feature consists of the mixtures listed in Table 1.

TABLE 1

In the vertical alignment liquid crystal display using the protrusions according to the exemplary embodiment of the present invention, the contrast ratio may be improved by forming the protrusion patterns with the black photosensitive resist. In addition, by using the black photosensitive resist, the manufacturing process can be simplified by using the projection pattern.

1A and 1B are layout views illustrating unit pixel structures of a color filter substrate and a thin film transistor substrate for a vertical alignment liquid crystal display according to a first embodiment of the present invention, respectively.

2A and 2B are layout views illustrating unit pixel structures of a thin film transistor substrate and a color filter substrate for a vertical alignment liquid crystal display according to a second exemplary embodiment of the present invention, respectively;

3 is a plan view of a unit pixel in the vertical alignment liquid crystal display according to the first and second embodiments of the present invention;

4 is a cross-sectional view of the projection pattern.

Claims (6)

Facing each other, transparent first and second insulating substrates, A liquid crystal layer injected between the first and second insulating substrates, A pixel electrode formed on the first insulating substrate, A first protrusion pattern formed on the pixel electrode to partially align the liquid crystal material; and A second projection pattern formed on the second insulating substrate to partially align the liquid crystal material; Including, The first protrusion pattern or the second protrusion pattern is formed of a black photosensitive resist, and divides the pixel electrode into a plurality of regions. In claim 1, A gate line formed on the first insulating substrate and transmitting a scan signal from the outside; and A data line insulated from and intersecting the gate line and transferring an image signal from the outside More, One of the first protrusion pattern and the second protrusion pattern overlaps the gate line and the data line. A gate line formed on the substrate and transferring a scan signal from the outside; A data line insulated from and intersecting the gate line and transferring an image signal from the outside; A pixel electrode formed in a first pixel region defined by the intersection of the gate line and the data line, A thin film transistor substrate formed on the pixel electrode, the thin film transistor substrate comprising a first protrusion pattern for dividing and aligning liquid crystal molecules; Red, green, and blue color filters formed in a second pixel region corresponding to the first pixel region; A common electrode facing the pixel electrode; A color filter substrate formed on the common electrode, the color filter substrate including a second protrusion pattern for dividing and aligning the liquid crystal molecules; The first and second protrusion patterns may be formed of a black photosensitive resist. 4. The vertical alignment liquid crystal display of claim 3, wherein the first protrusion pattern serves as a black matrix for absorbing light leaked between the pixel electrodes. 4. The vertical liquid crystal display of claim 3, wherein the second protrusion pattern serves as a black matrix for absorbing light leaked between the second pixel areas. Facing each other, transparent first and second insulating substrates, A liquid crystal layer injected between the first and second insulating substrates, A pixel electrode formed on the first insulating substrate, and Protrusion patterns formed on the second insulating substrate to divide and align the liquid crystal material, and formed of a black photosensitive resist. Including, The projection pattern divides the pixel electrode into a plurality of regions.