KR20080020322A - LCD Display - Google Patents

Abstract

An LCD is provided to increase the transmissive area of second and fourth pixel electrodes and reduce trasnmissive areas of first and third pixel electrodes, thereby reducing brightness difference between a central area and a gate driving unit side of a display area. An LCD(Liquid Crystal Display) comprises the followings. An LC panel is connected to a gate driving unit. A light source transmits light to the LC panel. Plural pixels receive a gate signal from the gate driving unit. In the plural pixels, transmissive areas(Y,X) where the light from the light source is transmitted according to be far from the gate driving unit increase. A light blocking unit(221) has an area(A,B) reduced according to be far from the gate driving unit and partitions the transmissive area by blocking a part of the pixel.

Description

Liquid Crystal Display {LIQUID CRYSTAL DISPLAY}

1 is a layout view of a first substrate and a second substrate in the liquid crystal display according to the first embodiment of the present invention;

FIG. 2 is an enlarged view of part I and part II in FIG. 1;

3 is a graph showing luminance characteristics in the liquid crystal display according to the first embodiment of the present invention;

4 is a layout view of a first substrate and a second substrate in the liquid crystal display according to the second embodiment of the present invention;

5A is an enlarged view of part III of FIG. 4, and FIG. 5B is an enlarged view of part IV of FIG.

Explanation of Signs of Major Parts of Drawings

100: first substrate 124: gate driver

122: gate electrode 161: pixel electrode

162: first pixel electrode 163: second pixel electrode

164: third pixel electrode 165: fourth pixel electrode

200: second substrate 221: light shield

222: first light blocking unit 223: second light blocking unit

224: third light blocking unit 225: fourth light blocking unit

The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device with improved display quality.

The liquid crystal display device includes a liquid crystal panel and a backlight unit for providing light to the liquid crystal panel. The liquid crystal panel includes a first substrate on which a thin film transistor is formed, a second substrate on which a common electrode and a color filter are formed, and a liquid crystal layer formed by injecting liquid crystal molecules therebetween.

The gate line and the data line provided on the first substrate cross each other to form pixels, and each pixel is connected to the thin film transistor. When a gate signal is applied to the gate line and the thin film transistor is turned on, the data voltage applied through the data line is charged to the pixel. The arrangement state of the liquid crystal layer is determined according to the electric field formed between the pixel voltage charged in the pixel and the common voltage formed on the common electrode of the second substrate.

The data voltage applied to the pixel is dropped by the parasitic capacitance between the gate electrode and the source electrode to form the pixel voltage. The voltage difference between the data voltage and the pixel voltage is called the kickback voltage.

The gate line receives a gate signal from the outside through a gate pad connected to an end thereof. A gate signal having a low delay is applied to a pixel adjacent to the gate pad, and a gate signal having a high delay is applied to a pixel electrode far from the gate pad.

However, the display voltage of the screen is deteriorated because the pixel voltage transferred to the pixel varies according to the delay level of the gate signal.

Accordingly, an object of the present invention is to provide a liquid crystal display device having improved display quality.

The above object is a liquid crystal display device comprising: a liquid crystal panel to which a gate driver is connected; A light source for sending light to the liquid crystal panel; A gate signal is applied from the gate driver, and the distance from the gate driver is achieved by a liquid crystal display including a plurality of pixels in which a transmission area through which light from the light source is transmitted increases.

The pixel may have a substantially same area, and may further include a light blocking part that partitions a transmission area by covering an area of the pixel and having an area that decreases away from the gate driver.

The liquid crystal panel may include a first substrate on which the pixel is formed, and a second substrate having the color filter and facing the first substrate, wherein the light blocking unit may partition between the color filters.

The gate driver may further include a gate line connecting the gate driver and the pixel, and the gate driver may include a shift register connected to an end of the gate line.

The gate driver may further include a gate line connecting the gate driver and the pixel, and the gate driver may be connected to both ends of the gate line.

Hereinafter, the present invention will be described with reference to the accompanying drawings.

A first substrate and a second substrate in the liquid crystal display according to the first embodiment of the present invention will be described with reference to FIGS. 1 and 2 as follows.

The liquid crystal display 1 includes a first substrate 100 on which a thin film transistor T is formed, a second substrate 200 on which a color filter 231 is formed, and a second substrate 200 facing the first substrate 100. It includes a liquid crystal layer positioned between (100, 200).

First, the first substrate 100 will be described. The first substrate 100 is a gate wiring 121, 122, 123 formed on the first insulating substrate 111 and the first insulating substrate 111 made of an insulating material such as glass, quartz, ceramic, or plastic. ) And data wirings 141, 142, and 143.

The gate wires 121, 122, and 123 are formed to extend in width at one end of the gate electrode 122 and the gate line 121 of the thin film transistor T connected to the gate line 121 and the gate line 121. The gate pad 123 is connected to the driver 124.

The gate driver 124 according to the present embodiment includes a flexible printed circuit board (not shown), a driving chip (not shown) mounted on the flexible printed circuit board, and a circuit board connected to the other side of the flexible printed circuit board. It represents a COF (chip on film) method that is disposed long along one edge of the liquid crystal panel. In another embodiment, a chip manufactured to generate a gate signal may be mounted on a thin film transistor substrate in the form of a chip on glass (COG), so that a circuit board may not be separately provided. According to another embodiment, the gate driver may be provided with a shift register in which a circuit wiring for generating a gate signal is provided in a process of forming circuit wiring of a thin film transistor substrate.

The gate insulating layer (not shown) formed on the gate lines 121, 122, and 123 is made of an insulating material such as silicon nitride (SiNx) or silicon oxide (SiOx).

A semiconductor layer 131 made of amorphous silicon is formed on the gate insulating film of the gate electrode 122, and an ohmic contact layer made of n + hydrogenated amorphous silicon doped with high concentration of silicide and n-type impurities is formed on the semiconductor layer 131. (Not shown) is formed. The ohmic contact layer is divided into two parts around the gate electrode 122.

Data lines 141, 142, and 143 are formed on the ohmic contact layer and the gate insulating layer.

The data lines 141, 142, and 143 are branches of the data line 141 and the data line 141 that cross the gate line 121 and define a pixel, and are formed on the upper portion of the ohmic contact layer. The width is extended to connect the source electrode 142 and the external circuit which are separated from the drain electrode 143 and formed on the ohmic contact layer opposite to the drain electrode 143 with respect to the gate electrode 122. A data pad (not shown).

A-Si: C: O film or a-Si: C: F deposited on the data lines 141, 142, and 143 and the semiconductor layer 131 which are not covered by the plasma enhanced chemical vapor deposition (PECVD) method. A protective film (not shown) made of a film, an acrylic organic insulating film, or the like is formed. The passivation layer is provided with a contact hole 151 for exposing the drain electrode 143 of the thin film transistor T.

On the passivation layer, a pixel electrode 161 is electrically connected to the drain electrode 143 through the contact hole 151 and positioned in the pixel.

The pixel electrode 161 is usually made of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO). The pixel electrode 161 is connected to the drain electrode 143 through the contact hole 152. The pixel electrode cut pattern 166 is formed on the pixel electrode 161. The pixel electrode cutting pattern 166 of the pixel electrode 161 divides the liquid crystal layer 300 into a plurality of regions together with a common electrode cutting pattern (not shown) which will be described later.

The pixel electrode 161 is connected to the gate driver 124 by the gate line 121, and is formed along one row parallel to the gate line 121. The pixel electrode 161 is sequentially provided along the gate line 121 from the position closest to the gate driver 124, the second pixel electrode 163, and the nth pixel electrode (not shown). City).

Next, the second substrate 200 will be described.

The second substrate 200 is a second insulating substrate 211 made of an insulating material such as glass, quartz, ceramic or plastic, the black matrix 221 and black formed in a lattice shape on the second insulating substrate 211. A color filter 231 and a common electrode layer (not shown) respectively formed in the opening region O of the matrix 221 are stacked. An overcoat film (not shown) is formed between the black matrix 221, the color filter 231, and the common electrode layer.

The black matrix 221 has an opening area O exposing each color filter, and distinguishes between the color filters 232 and 233. When the first substrate 100 and the second substrate 200 are matched, the black matrix 221 surrounds the pixel electrodes 162 and 163 and has gate gates 121, 122, 123, data wires 141, 142, 143, and thin film transistor T. Is formed to be disposed on to block the direct light irradiation to the thin film transistor (T).

The first light blocking unit 222 and the second light blocking unit 223 are disposed on the first pixel electrode 162 and the second pixel electrode 163 which are sequentially provided along the gate line 121. The area A of the first light blocking portion 222 is larger than the area B of the second light blocking portion 223.

The color filter 231 is formed by repeating the red filter 232, the green filter 233, and the blue filter 234 around the black matrix 221. The color filter 231 serves to impart color to light emitted from the backlight unit (not shown) and passed through the liquid crystal layer 300. The color filter 231 is usually made of a photosensitive organic material.

An overcoat layer (not shown) is formed on the black matrix 221 not covered by the color filter 231 and the color filter 231. The overcoat layer serves to protect the color filter 231 while planarizing the color filter 231. The overcoat layer may be a photosensitive acrylic resin.

A common electrode (not shown) is formed on the overcoat layer. The common electrode is made of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO). The common electrode directly applies a voltage to the liquid crystal layer together with the pixel electrode 161 of the thin film transistor substrate.

Hereinafter, the display quality of the liquid crystal panel according to the present embodiment will be described with reference to FIG. 3. Fig. 3 shows the luminance, the aperture ratio of the color filter, and the voltage characteristics at positions away from the gate driver in the liquid crystal display device in the normally black mode.

The first substrate 100 is provided with a gate line 121 for transmitting a scan signal and a data line 141 for transmitting an image signal to form a pixel area. The pixel electrode 161 formed in each pixel area is formed of a gate. Rows are formed along the gate line 121 connected to the driver 124. The gate line 121 receives a gate signal of the gate driver 124 through a gate pad 123 connected to an end of the gate line 121. A gate signal having a low delay is applied to the first pixel electrode 162 adjacent to the gate driver 124, and a gate signal having a high delay is applied to the second pixel electrode 163 far from the gate driver. As a result, a gate signal is properly applied to the first pixel electrode 162 to transmit a desired data voltage, but the second pixel electrode 163 is not properly applied to the data voltage. Therefore, in the related art, as shown in FIG. 3, the first pixel electrode 162 adjacent to the gate driver 124 has a higher luminance than the second pixel electrode 163 far from the gate driver 124 and other pixel electrodes in the same row. The display defect occurred.

However, in the first exemplary embodiment of the present invention, the display failure problem is solved by changing the transmission areas of the pixel electrodes 162 and 163. In more detail, the transmissive areas of the pixel electrodes 162 and 163 may be changed by changing the area of the light blocking portion disposed on the pixel electrodes 162 and 163.

Each of the pixel electrodes 162 and 163 has substantially the same area, and includes a first light blocking portion 222 disposed on the first pixel electrode 162 disposed closest to the gate driver 124. Has a larger area than the second light blocking portion 223 disposed on the second pixel electrode 163.

The light blocking portions 222 and 223 block portions of the pixel electrodes 162 and 163 to partition a transmission area through which light can pass through the pixel electrodes 162 and 163. The area A is larger than the area B of the second light blocking portion 223. Therefore, the transmission area Y of the second pixel electrode 163 becomes larger than the transmission area X of the first pixel electrode 162 and is larger than the first pixel electrode 162 through the second pixel electrode 163. More light is emitted.

Since the first pixel electrode 162 is provided closer to the gate driver 124 than the second pixel electrode 163, a higher gate signal is applied than the second pixel electrode 163 as described above. Although it appears bright, the transmission area X of the first pixel electrode 162 according to the present embodiment is smaller than the transmission area Y of the second pixel electrode 163. Therefore, the amount of light emitted through the first pixel electrode 162 is reduced compared to the conventional case in which the transmission areas of the first pixel electrode 162 and the second pixel electrode 163 are the same. Therefore, the problem of brightening of an area adjacent to the gate driver is reduced.

That is, the transmissive area of the pixel electrode, which is brighter with a small delay of the gate signal adjacent to the gate driver 124, is reduced, and the transmissive area of the pixel electrode having a large delay of the gate signal is increased because the pixel electrode is disposed far away from the gate driver 124. As shown in FIG. 3, the difference in luminance between the gate driver 124 side and the other area on the display area is reduced.

Hereinafter, a liquid crystal display according to a second exemplary embodiment of the present invention will be described with reference to FIGS. 4 and 5. In the liquid crystal display device according to the present embodiment, the configuration other than the gate driver and the light blocking portion is the same as in the first embodiment of the present invention.

The gate driver includes a first gate driver 124 and a second gate driver 125 provided in pairs along both edges of the liquid crystal panel. Gate lines 121 and 122 formed in a horizontal direction on the first substrate 100 to form a plurality of rows are connected to the first gate driver 124 and the second gate driver 125 at both ends to apply a gate signal. Receive.

Pixel electrodes 162, 163, 164, and 165 are provided in a pixel region formed by a plurality of data lines that intersect the gate line 121.

The first pixel electrode 162 and the second pixel electrode 163 may be defined in the order closest to the first gate driver 124. The first light blocking unit 222 and the second light blocking unit 223 are formed on the first pixel electrode 162 and the second pixel electrode 163, and the area A of the first light blocking unit 222 is formed. Is larger than the area B of the second light blocking unit 223, and the area X through which light passes through the first pixel electrode 162 is Y through which light passes through the second pixel electrode 163. Small compared to).

The third light blocking unit 224 and the fourth light blocking unit 225 are disposed on the third pixel electrode 164 and the fourth pixel electrode 165 which are arranged in the order adjacent to the second gate driver 125. have. The area C of the third light blocking part is larger than the area D of the fourth light blocking part, and the area α through which the light is transmitted from the third pixel electrode 164 is determined by the light of the fourth pixel electrode β. Small compared to the area to be transmitted.

The first pixel electrode 162 and the third pixel electrode 164 provided near the gate driving units 124 and 125 have a higher gate signal than the second pixel electrode 163 and the fourth pixel electrode 165. Is approved. In the conventional case where the areas A, B, C, and D of all the light blocking portions are the same, the luminance on the pixel electrodes 162 and 164 provided near the gate drivers 124 and 125 is high, and the gate drivers 124 and 125 are high. The luminance of the second pixel electrode 163 and the fourth pixel electrode 165 far from the? Therefore, the liquid crystal panel 100 has a problem that the center region is dark and the edge where the gate drivers 124 and 125 are disposed is viewed brightly, resulting in uneven luminance.

However, according to the present exemplary embodiment, the second light blocking part 223 and the fourth light blocking part 225 disposed on the second pixel electrode 163 and the fourth pixel electrode 165 disposed far away from the gate driving parts 124 and 125. Becomes small, and the first light blocking portion 222 and the third light blocking portion 224 of the first pixel electrode 162 and the third pixel electrode 164 disposed adjacent to the gate driving portions 124 and 125 Grows

Therefore, the transmission areas (Y, β) of the second pixel electrode 163 and the fourth pixel electrode 165 in the central region, which are disposed far from the gate drivers 124 and 125 and are darkly seen, are increased, and the gate drivers 124, The transmissive areas X and α of the first pixel electrode 162 and the third pixel electrode 164 disposed adjacent to and brightly visible are reduced, so that the gate drivers 124 and 125 and the central area of the display area are reduced. The luminance difference between them is reduced.

As described above, according to the present invention, a liquid crystal display device having improved display quality is provided.

Claims (5)

In the liquid crystal display device, A liquid crystal panel to which a gate driver is connected; A light source for sending light to the liquid crystal panel; And a plurality of pixels that receive a gate signal from the gate driver and increase a transmission area through which light from the light source is transmitted as the distance from the gate driver increases. The method of claim 1, And the pixel is formed of substantially the same area, and further includes a light blocking portion that divides a transmission area by covering a portion of the pixel and having an area that decreases away from the gate driver. The method of claim 1, The liquid crystal panel includes a first substrate on which the pixel is formed, and a second substrate having the color filter and facing the first substrate, wherein the light blocking unit divides between the color filters. LCD display device. The method of claim 1, A gate line connecting the gate driver and the pixel; And the gate driver is connected to both ends of the gate line. The method of claim 1, And a gate line connecting the gate driver and the pixel, wherein the gate driver includes a shift register connected to an end of the gate line.

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