CN100470328C - Liquid crystal display and color filter array plate - Google Patents

Abstract

This liquid crystal display includes a liquid crystal display panel having a red filter having red pixels, a green filter having green pixels, a blue filter having blue pixels and white pixels W; and a back light unit disposed in one side of the panel. Light emitted from the back light unit has x-color coordinates ranging from 0.31 to 0.34, and y-color coordinates from 0.32 to 0.35.

Description

Liquid crystal display and its color filter array board

This application is a divisional application of the No. 03127473.0 invention patent application with the filing date of May 4, 2003, entitled "Liquid Crystal Display and Its Color Filter Array Board".

technical field

The invention relates to a liquid crystal display and a used display panel, in particular to a four-color liquid crystal display.

Background technique

In general, a liquid crystal display (LCD) includes: a liquid crystal panel assembly (liquid crystal panel assembly), which includes two panels provided with two types of field generating electrodes such as a pixel electrode and a common electrode; A liquid crystal layer with anisotropic dielectric properties between them. A change in the voltage difference between the field generating electrodes, that is, a change in the intensity of an electric field generated by the electrodes, causes a change in light transmittance through the LCD, and thus, controlling the voltage difference between the electrodes can obtain a prescribed image.

The LCD includes multiple pixels with pixel electrodes and red (R), green (G), and blue (B) color filters. The pixels are driven to perform display operations by means of signals applied through display signal lines. The signal lines include gate lines (or scan signal lines) carrying scan signals, and data lines carrying data signals. Each pixel has a thin film transistor (TFT) connected to a gate line and a data line to control a data signal applied to the pixel electrode.

Existing LCDs that represent one dot with three RGB color pixels have poor optical efficiency. Specifically, the color filters for each RGB pixel transmit only 1/3 of the incident light, and therefore, the overall optical efficiency is poor.

Thus, there are several arrangements of red (R), green (G), and blue (B) color filters. For example: strip arrangement, where color filters of the same color are arranged in the same pixel column; mosaic arrangement, where red, green, and blue color filters are arranged sequentially along rows and columns; delta-type arrangement, where pixels are arranged in the column direction The top is arranged in a zigzag shape, and the red, green, and blue color filters are arranged in sequence. A delta-shape accurately represents a circle or a diagonal.

Clair Voyante's laboratory proposed a pixel arrangement called "PenTile Matrix ^TM ". Its advantage is that it can display high-definition images and minimize the design cost. In this pixel arrangement, the blue unit pixel is shared by two dots, and adjacent blue pixels receive a data signal from one data driver IC and are driven by two different gate driver ICs. With the PenTileMatrix pixel structure, Super Video Graphics Array (SVGA) level displays can be used to achieve Ultra Large Graphics Array (UXGA) level high definition. In addition, the number of low-cost gate driver ICs is increased and the number of high-cost data driver ICs is reduced. The cost of the display is thereby minimized.

However, with the PenTile Matrix pixel structure, since the size of the blue pixel is different from that of the red and green pixels, alternate storage capacity is required due to the difference in liquid crystal charging rate. Also, since two blue pixels are driven with one wire, the pixel polarity is not consistent.

Especially when the blue pixels are arranged in stripes, the vertical line pattern caused by the blue pixels becomes easily visible with insufficient definition, which degrades the overall image quality.

Contents of the invention

A liquid crystal display is provided, comprising: a liquid crystal display panel assembly having a plurality of red, green, blue and white pixel areas; and a backlight unit placed on the side of the liquid crystal display panel assembly, wherein the light emitted by the backlight unit has a Coordinates (color coordinate) (x, y), x ranges from about 0.31 to about 0.34, and y ranges from about 0.32 to about 0.35.

The liquid crystal display panel assembly includes: a first insulating substrate; a plurality of thin film transistors formed on the first insulating substrate; a plurality of pixel electrodes formed on the first insulating substrate and connected to the thin film transistors; A second insulating substrate at the bottom; a black matrix formed on the second insulating substrate and defining a pixel region; red, green and blue color filters substantially formed in the red, green and blue pixel regions respectively; forming a common electrode on the color filter; and a liquid crystal layer sandwiched between the first and second insulating substrates.

The area of the blue pixel area or the white pixel area is smaller than that of the red pixel area and the green pixel area.

Preferably, the total area of the blue pixel area and the white pixel area is substantially the same as that of any one of the red pixel area and the green pixel area.

The width of the black matrix near the white pixel area is preferably wider than that of the black matrix near the other pixel areas.

A color filter array panel for a liquid crystal display is provided, comprising: an insulating substrate; a black matrix formed on the insulating substrate and defining red, green, blue and white pixel areas; , red, green, and blue organic color filters containing red, green, and blue pigments in the blue pixel area; a transparent organic color filter basically formed in the white pixel area; and a common electrode formed on the organic color filter .

The color filter array plate also includes an overcoat between the organic color filter and the common electrode.

The transparent organic color filter may comprise the same material as the coating.

Preferably, the surface of the coating is approximately uniform in height.

A liquid crystal display is provided, which includes: a first insulating substrate; a plurality of thin film transistors formed on the first insulating substrate; a protective layer having a protruding portion formed on the thin film transistor; a protective layer formed on the protective layer and connected to the thin film transistor A plurality of pixel electrodes; a second insulating substrate facing the first insulating substrate; a black matrix formed on the second insulating substrate and used to define red, green, blue and white pixel regions; respectively formed substantially on Red, green, and blue color filters in the red, green, and blue pixel regions; a common electrode formed on the color filters; and a liquid crystal layer interposed between first and second insulating substrates, wherein, in white The height of the common electrode in the pixel area is smaller than that in the red, green and blue pixel areas, and the protruding portion of the protection layer faces the white pixel area.

The distance between the common electrode and the surface of the protective layer is preferably substantially uniform.

The pixel electrode and the common electrode may have cutouts.

A liquid crystal display is provided, which includes: an array of multiple groups of pixels, each group of pixels includes a blue pixel and a white pixel adjacent to each other, a pair of red pixels straddling the blue pixel and the white pixel diagonally opposite to each other, and a straddling A pair of green pixels oblique to each other passing through the blue pixel and the white pixel and adjacent to the red pixel, each pixel includes a pixel electrode and a thin film transistor; a plurality of gates extending in the row direction for transmitting gate signals to the pixel lines; and a plurality of data lines extending in a column direction and for transmitting data signals to the pixels.

The relative positions of the blue pixels and the white pixels in two adjacent groups of pixels in the column direction or the row direction are preferably opposite.

According to an embodiment of the present invention, a pixel has a rectangular shape, and blue pixels and white pixels are arranged in a column direction to form separate columns.

According to another embodiment of the present invention, the blue pixel and the white pixel are triangular to form a rhombus, and the boundary line between the blue pixel and the white pixel extends in a row direction or a column direction.

Preferably, the red pixels in two adjacent columns are located in different rows, and the red pixels in those adjacent rows are located in different columns, wherein the green pixels in two adjacent columns are located in different rows, and Green pixels in adjacent rows are located in different columns, and wherein blue pixels or white pixels in two adjacent groups of pixels in the row direction are located in different rows, or blue pixels in two adjacent groups of columns in the column direction Or the white pixels are in different columns.

The liquid crystal display can be driven by rendering.

Description of drawings

The above-mentioned and other advantages of the present invention will become clearer by describing preferred embodiments of the present invention in conjunction with the accompanying drawings, wherein:

1 is a cross-sectional view of an LCD according to an embodiment of the present invention;

2 to 5 are schematic diagrams of color filter arrangements for LCDs according to embodiments of the present invention;

Fig. 6 is a schematic spectrum graph showing a light source according to an embodiment of the present invention;

7 and 8 are cross-sectional views of a color filter array plate for an LCD according to an embodiment of the present invention;

Fig. 9 is a graph of the function relationship between the response time of LCD and its display cell gap (cell gap);

10 is a cross-sectional view of an LCD according to another embodiment of the present invention;

11 to 13 are schematic diagrams of pixel arrangement of an LCD according to an embodiment of the present invention;

Figure 14 is a picture of the visibility of an LCD with the pixel arrangement shown in Figure 11;

Figures 15 and 17 are respectively the layout of the TFT array plate used by the LCD according to the embodiment of the present invention, and Figures 16 and 18 are respectively the TFT arrays shown in Figures 15 and 17 cut along the lines XVI-XVI' and XVIII-XVIII' Sectional view of the plate;

Fig. 15 is the layout diagram of the TFT array plate used by the LCD with pixel arrangement shown in Fig. 11 according to an embodiment of the present invention;

Fig. 16 is a sectional view of the TFT array plate shown in Fig. 15 cut along the line XVI-XVI';

Fig. 17 is the layout diagram of the TFT array board used for the LCD with the pixel arrangement shown in Fig. 12 according to an embodiment of the present invention; and

Fig. 18 is a sectional view of the TFT array panel shown in Fig. 17 taken along line XVIII-XVIII'.

Detailed ways

The present invention is described more fully hereinafter with reference to the accompanying drawings showing preferred embodiments of the invention.

Layer thicknesses and areas in the figures are exaggerated for better clarity. The same reference numerals designate the same elements. It will be understood that when an element such as a layer, region or substrate is said to be "on" another element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element is said to be "directly on" another element, there are no intervening elements.

An LCD according to an embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view of an LCD according to an embodiment of the present invention. 2 to 5 show the arrangement of color filters of an LCD according to an embodiment of the present invention.

As shown in FIG. 1, the LCD includes a lower plate 100, an upper plate 200 facing the lower plate 100, and a liquid crystal layer 3 sandwiched between the lower plate and the upper plate and containing liquid crystal molecules aligned in a predetermined direction. The LCD also includes upper and lower polarizers 12 and 22 , upper and lower compensation films 13 and 23 , and a backlight unit 350 . The orientation of the liquid crystal molecules changes when an electric field is applied. The light transmittance varies with the orientation of the liquid crystal molecules.

The lower plate 100 includes: a lower substrate 110 preferably made of a transparent insulating material such as glass, a plurality of thin film transistors (TFTs) formed on the lower substrate 110, and a plurality of thin film transistors (TFTs) connected to the TFTs and preferably made of, for example, indium tin oxide (ITO ) and a plurality of pixel electrodes 190 made of transparent conductive materials of indium zinc oxide (IZO). Each TFT converts a data voltage applied to the pixel electrode 190 .

The lower compensation film 13 and the lower polarizer 12 are attached to the outer surface of the lower substrate 110 . The lower compensation film 13 is biaxial or uniaxial. The lower compensation film 13 may be omitted.

The upper plate 200 includes: an upper substrate 210 preferably made of a transparent insulating material such as glass, a black matrix 220 defining a plurality of pixel regions arranged in a matrix, and a plurality of red pixels formed in the pixel regions defined by the black matrix 220. , green and blue color filters 230R, 230G and 230B, and a common electrode 270 preferably made of a transparent conductive material such as ITO and IZO.

Red, green, and blue color filters 230R, 230G, and 230B are arranged in sequence. A pixel area without any red, green, and blue color filters 230R, 230G, and 230B represents a white pixel area W, which equally blocks or passes all components of incident light. Since there is no color filter in the white pixel area W, the inner surface height of the color filter plate 200 on the white pixel area W is smaller than the inner surface height of the color filter plate 200 on other R, G, and B pixel areas. The display unit gaps on the white pixel area W are larger than the display unit gaps on other pixel areas.

In this specification, the technical term "pixel" refers to a basic functional element for displaying images, which includes a pixel electrode 190, a part of the common electrode 270 facing the pixel electrode 190, and a corresponding part between the pixel electrode 190 and the common electrode 270. A part of the liquid crystal layer 3, a TFT, and a color filter 230R, 230G or 230B. In addition, the term "pixel area" refers to an area occupied by a pixel. However, for convenience of description, the two terms "pixel" and "pixel region" are used without distinction in this specification.

Referring to FIG. 2, the red, green, blue and white pixel regions R, G, B and W have the same number. The red, green, blue and white pixel areas R, G, B and W are sequentially arranged in the row direction. The size of each of the blue pixel area B and the white pixel area W is half that of each of the red pixel area R and the green pixel area G. Therefore, the sum of one blue pixel area B and one white pixel area W is approximately the same as one red pixel area R or one green pixel area G.

Referring to FIG. 3 , a 2×3 pixel array including identical pixels forms a dot as a basic element of an image. The first pixel row includes sequentially arranged red, blue and green pixels, and the second pixel row includes sequentially arranged green, white and red pixels.

The pixel arrangement shown in FIG. 4 is the same as that shown in FIG. 3, except that the blue pixel B is enlarged, and the white pixel W is reduced.

The pixel arrangement shown in FIG. 5 is the same as the pixel arrangement shown in FIG. 3, except that the part of the black matrix BW surrounding the white pixel W is enlarged to have a wider width than other parts, which is set to conceal the Rotate the displacement (disclination) line.

The upper compensation film 23 and the upper polarizer 22 are attached to the outer surface of the upper substrate 210 . The upper compensation film 23 is biaxial or uniaxial. The upper compensation film 23 may be omitted.

The backlight unit 350 is placed on the back of the lower polarizer 12 . The backlight unit 350 is provided with a light source 351 including a cold cathode tube and a light guide plate 352 .

In this embodiment, since one dot includes red, green, blue and white pixels, the optical efficiency can be improved without increasing the total area of the dot.

Assume that the amount of light passing through the lower polarizer 12 is 1.

For a dot of 3 pixels including red, green, and blue pixels, the area of each pixel is 1/3 of the total area of the dot. Since the light transmittance of the color filter is 1/3, the total light transmittance of the point is equal to 1/3×1/3+1/3×1/3+1/3×1/3=1/3≈ 33.3%.

With respect to the points shown in FIG. 2, the area of each red and green pixel is 1/3 of the total area, and the area of each blue and white pixel is 1/6 of the total area. Since the light transmittance of the white pixel is 1, and the light transmittance of other pixels is 1/3, the total light transmittance of the point is equal to 1/3×1/3+1/3×1/3+1/6 ×1/3+1/6×1=4/9≈44.4%. Therefore, compared with the existing three-color LCD, the brightness is increased to about 1.5 times.

Although the area of a blue pixel is smaller than that of a red or green pixel, people are less sensitive to changes in the amount of blue light than red and green light, so the reduced area has less impact on image quality.

However, the reduced area of the blue pixels degrades the image slightly, ie, makes the image slightly yellowish.

In order to overcome this disadvantage, the blue component of the light emitted by the light source 351 is increased to prevent yellowish images from appearing.

Light emitted by light source 351 has color coordinates (x, y), where x ranges from about 0.31 to about 0.34 and y ranges from about 0.32 to about 0.35. This light contains more blue light components than the light emitted by existing LCD backlight sources. To obtain such a light source, the blue light-emitting material contained in the light source 351 should be increased by a predetermined amount.

FIG. 6 is a graph showing an exemplary spectrum of a light source according to an embodiment of the present invention. When compared to the spectral curves of existing light sources denoted "Blue 1", the curves denoted "Blue 1.09" and "Blue 1.18" show increased peaks at wavelengths in the range of about 440-470nm, which range represents blue light, and A reduced peak at wavelengths in the range of about 620-650 nm, which represents red light.

Meanwhile, since the white pixel W has no color filter, the light output of the white pixel W from the light source 531 can be seen as bluish. However, the larger cell gap of the white pixel W, which makes the incident light yellow, prevents the light from bluish.

7 and 8 are cross-sectional views of a color filter array panel for an LCD according to another embodiment of the present invention.

Referring to Fig. 7, the color filter array board 200 includes: a transparent insulating substrate 210, a black matrix 220 formed on the insulating substrate 210 with a plurality of small holes defining pixel areas, and a plurality of red and green holes formed in each pixel area. , blue and transparent color filters 230R, 230G, 230B, and 230W, a coating layer 250 formed on the color filters 230R, 230G, 230B, and 230W, and a common electrode 270 formed on the coating layer 250 . The transparent color filter 230W preferably comprises a transparent organic material, such as a pigment-free photosensitive material.

The color filter array panel 200 shown in FIG. 8 does not include transparent color filters. Instead, a portion of the coating layer 250 in the white pixel region W is thicker than other portions thereof, resulting in a surface level difference equal to or less than 0.2 μm. Therefore, the display unit gaps of all pixels are almost the same. Compared with the color filter array plate 200 shown in FIG. chip array plate 200.

The color filter array plate 200 shown in FIGS. 7 and 8 reduces the difference between the white pixel W and other pixel regions R, G by setting a transparent color filter 230W, or by increasing the thickness of the coating 250 at the white pixel W. and the step difference between B.

The reduced step difference and consistent display cell gap prevents yellow light from appearing in the white pixel area W and rotational displacement lines from appearing at the steps.

Preferably, the thickness of the display cell gap or the liquid crystal layer is equal to about 3.7 μm, and the thickness of the color filter is about 1.5 to 1.6 μm.

FIG. 9 is a graph showing response time as a function of gap between display cells of an LCD.

In Figure 9, "on" represents the turn-on response time, and "off" represents the turn-off response time.

As shown in FIG. 9, the response time decreases as the display cell gap increases. The response time is at a minimum when the display cell gap reaches 3.7μm. The response time increases again as the display cell gap moves away from 3.7 μm.

Fig. 10 is a sectional view of an LCD according to another embodiment of the present invention.

Referring to FIG. 10, the LCD according to this embodiment includes: a TFT array panel, a color filter array panel 200 and a liquid crystal layer 3 interposed therebetween.

The color filter array plate 200 includes: an upper plate 210 preferably made of a transparent insulating material such as glass, a black matrix 220 formed on the upper plate 210 to define a plurality of pixel areas arranged in a matrix, basically located in the pixel area A plurality of red, green, and blue color filters 230R, 230G, and 230B, a coating layer 250 formed on the color filters 230R, 230G, and 230B, and preferably made of a transparent conductive material such as ITO and IZO and multiple A common electrode 270 with a cutout 271.

Red, green and blue color filters 230R, 230G and 230B are arranged in sequence. A pixel area without any of the red, green, and blue color filters 230R, 230G, and 230B represents a white pixel area W, which equally blocks or passes all components of incident light. Since there is no color filter in the white pixel area W, the inner surface of the color filter plate 200 on the white pixel area W forms a basin-shaped structure.

The TFT array board 100 includes a plurality of gate electrodes 123 formed on an insulating substrate 110, a gate insulating layer 140 formed on the gate electrodes 123, and a gate insulating layer 140 formed on the gate insulating layer 140 opposite to the gate electrodes 123 is preferably A plurality of semiconductors 154 made of amorphous silicon, a plurality of ohmic contact layers 163 and 165 formed on the semiconductor 154, and a plurality of source and drain electrodes 173 and 175 respectively formed on the ohmic contact layers 163 and 165 cover the source and drain electrodes. The electrodes 173 and 175 are combined with a protection layer 180 having a plurality of contact holes 181 exposing the drain electrode 175 , and a plurality of pixel electrodes connected to the drain electrode 175 through the contact holes 181 and having a plurality of cutouts 191 . The TFT array board 100 is also provided with a plurality of gate lines (not shown) connected to the gate electrodes 123 for delivering scan signals thereto, and a plurality of data lines connected to the source electrodes 173 for delivering data signals thereto (not drawn).

The surface of the protective layer 180 protrudes from the white pixel W to form a protrusion.

The basin-shaped structure of the color filter array board and the boss of the TFT array board are opposite to each other, so that the white pixel area W and other pixels have approximately the same display unit gap.

The protective layer 180 described above is formed by photolithography using a photomask having translucent regions and transparent and opaque regions. After depositing the protective layer 180 and covering it with a photoresist film, align the photomask so that the transparent area and the opaque area face the contact hole 181 and the white pixel area W, while the semi-transparent area faces the remaining areas . After exposure and development, the portion of the photoresist film on the contact hole 180 is removed to expose a portion of the protective layer 180, leaving the portion above the white pixel region W, and the thickness of the other portion is reduced. The contact hole 181 is formed by etching using the photoresist film as an etching mask, and the photoresist film is ashed, so that a portion of the photoresist film whose thickness is reduced is removed, exposing a part of the protective layer 180. . Therefore, only the photoresist film portion on the white pixel area W is left. The protective layer 180 is etched using the photoresist film as an etching mask so that the exposed portion of the protective layer 180 is thinned to form a mesa on the white pixel region W. Referring to FIG.

Meanwhile, multiple photolithography steps are introduced in the manufacture of the TFT array panel 100, and the use of a photomask having semi-transparent regions as well as transparent and opaque regions reduces the number of photolithography steps. Several layers with different patterns can be formed with a photoresist film having a position-dependent thickness made using a photomask. For example, the semiconductor 154, the ohmic contact layers 163 and 165, and the source electrode 163 and the drain electrode 165 are formed with this photoresist film, therefore, compared with the case of using a photomask having only transparent and opaque regions, The TFT array panel 100 can be fabricated with fewer masks. In this case, the source electrode 163 and the drain electrode 165 have substantially the same planar shape as the ohmic contact layer, and the semiconductor 154 has substantially the same planar shape as the source electrode 163 and the drain electrode 165 except for the channel region.

The TFT array board 100 and the color filter array board 200 are aligned for assembly. Then, the liquid crystal material 3 is injected into the gap between the TFT array panel 100 and the color filter array panel 200 and vertically aligned. A pixel region representing a portion of the liquid crystal layer 3 in a pixel is divided into a plurality of domains by the cutouts 191 and 271 of the pixel electrode 190 and the common electrode 270 . These domains are classified into 4 types according to the tilt directions of the liquid crystal molecules therein under the application of an electric field. Multiple domains can provide a wide viewing angle.

11 to 13 show pixel arrangements according to another embodiment of the present invention.

11 to 13, the LCD according to this embodiment includes red, blue and green pixels R, B and G arranged like a PenTile Matrix, and a white pixel W adjacent to the blue pixel B.

For the convenience of description, it is specified that the pixel group includes: blue and white pixels B and W adjacent to each other, a pair of red pixels R straddling blue and white pixels B and W diagonally opposite each other, a pair of blue and white pixels B and W straddling W is a green pixel G diagonally opposite to each other and adjacent to a red pixel R. Then, this arrangement of pixel groups is repeated to obtain the pixel arrangements of FIGS. 11 to 13 . Note that the relative positions of the blue pixel B and the white pixel W in two groups of pixels adjacent in the column direction or the row direction are reversed.

The blue pixel B and the white pixel W shown in FIG. 11 are rectangular, like the red pixel R and the green pixel G, and are arranged in the column direction to form separate columns.

Alternatively, the blue pixel B and the white pixel W shown in FIGS. 12 and 13 are isosceles triangles, and a pair of blue pixel B and white pixel W have their bases facing each other to form a rhombus. The blue pixels B and white pixels W shown in FIG. 12 are arranged in the column direction, while the blue pixels B and white pixels W shown in FIG. 13 are arranged in the row direction. Therefore, the boundary line between blue pixel B and white pixel W shown in FIG. 12 matches the boundary line between pixel rows, while the boundary line between blue pixel B and white pixel W shown in FIG. 13 matches the pixel column The borderline between matches.

Referring to FIGS. 11 and 12 , the relative positions of the blue pixel B and the white pixel W in two adjacent groups of pixels in the row direction are reversed. However, referring to FIG. 13 , the relative positions of the blue pixel B and the white pixel W in two adjacent groups of pixels in the column direction are reversed.

In this arrangement, the red pixels R in two adjacent columns are located in different rows, and the red pixels R in adjacent rows are located in different columns. Likewise, the green pixels G in two adjacent columns are located in different rows, and the green pixels G in adjacent rows are located in different columns. In addition, the blue pixels B or white pixels W in two adjacent groups in the row direction are located in different rows, as shown in Figures 11 and 12; or, the blue pixels B or white pixels in two adjacent groups in the column direction Pixels W are located in different columns, as shown in FIG. 13 . Therefore, pixels of the same color, especially blue pixels, are arranged in zigzag along the column direction and the row direction.

The LCD according to these embodiments receives RGB image data from an external data source such as an image controller, and extracts image data of white pixels W to drive 4-color pixels.

The dots displaying the image preferably include the above-mentioned pixel group, which includes: a pair of blue pixels B and white pixels W, a pair of red pixels R and a pair of green pixels G.

However, when plotting, a point can include a pair of blue pixels B and white pixels W, and a pair of red and green pixels in a column.

In any case, these pixel arrangements prevent the vertical line pattern produced in conventional LCDs in which pixels of the same color, such as blue pixels, are arranged in a column direction, and the definition is not high enough. Therefore, LCD with PenTile Matrix pixel arrangement can improve image quality.

FIG. 14 is a graph showing the visibility of an LCD having the pixel arrangement shown in FIG. 11. FIG. As shown in Figure 14, there is no discernible vertical line pattern.

An exemplary TFT array panel for an LCD having the pixel arrangement shown in FIGS. 11 and 12 will be described below with reference to FIGS. 15 to 18. FIG.

Figures 15 and 17 are the layouts of the TFT array plate used for LCD according to the embodiment of the present invention, and Figures 16 and 18 are the TFT array plates shown in Figures 15 and 17 cut along the lines XVI-XVI' and XVIII-XVIII' respectively cutaway view.

Referring to FIG. 12, the LCD according to these embodiments includes a plurality of red, green, blue and white pixels R, G, B and W arranged in row and column directions.

As shown, a gate wiring is formed on a transparent insulating substrate 110 . The gate wiring includes a plurality of gate lines 121 extending substantially in a row direction and a plurality of gate electrodes 123 connected to the gate lines 121 . The end 125 of each gate line 121 is widened to be connected with an external circuit.

The gate wiring is preferably formed of a metal having low resistivity, for example, aluminum, silver, or the like.

A gate insulating layer 140 is formed on the entire surface of the substrate including the gate wiring.

A plurality of semiconductor islands 154 preferably made of amorphous silicon are formed on the gate insulating layer 140, and a plurality of ohmic contacts preferably made of amorphous silicon heavily doped with silicide or n-type impurities are formed on the semiconductor islands 154. Layers 163 and 165.

On the ohmic contact layers 163 and 165 and the gate insulating layer 140 are formed data wirings preferably made of a metal having low resistivity, such as aluminum, silver, or the like.

The data wiring includes: a plurality of data lines 171 extending approximately in the column direction and crossing the gate lines 121 to define a plurality of pixel regions, a plurality of source electrodes 173 as branches of the data lines 171 and extending to the ohmic contact layer 163, and A plurality of drain electrodes 175 separated from the source electrode 173 and formed on the ohmic contact layer 165 opposite to the source electrode 173 with respect to the gate electrode 123 . The end 179 of each data line 171 is widened to be connected with an external circuit.

A passivation layer 180 is formed on the data wiring and the exposed portion of the semiconductor island 154 not covered by the data wiring. The passivation layer 180 has a plurality of contact holes 185 and 189 exposing the drain electrode 175 and the end portion 179 of the data line 171, respectively. The passivation layer 180 and the gate insulating layer 140 have a plurality of contact holes 182 exposing the ends 125 of the gate lines 121 .

A plurality of pixel electrodes 190 and a plurality of contact assistants 95 and 97 are formed on the passivation layer 180 . Pixel electrode 190 is respectively connected to drain electrode 175 and storage electrode 177 through contact holes 185 and 187, and auxiliary contacts 95 and 97 are connected to exposed end 125 of gate line 121 and exposed end 179 of data line 171 through contact holes 182 and 189, respectively. The pixel electrode 190 and the auxiliary contacts 95 and 97 are preferably formed of a transparent material such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide).

The gate electrode 123, the source electrode 173 and the drain electrode 175, and the semiconductor island 154 form a TFT.

15 and 16, each pixel R, G, B and W has the same rectangle as shown in FIG. Also consistent. The data wiring also includes a plurality of storage conductors 177 covering the extended portion of the gate line 121 , and the passivation layer 180 further includes a plurality of contact holes 187 for connecting the pixel electrode 190 and the storage electrode 177 . Each gate line 121 has a plurality of extended portions overlying the storage electrode 177 to form a storage capacitor.

Referring to FIGS. 17 and 18 , the shape of the pixel electrode 190 of the pixels R, G, B, and W is similar to that of the corresponding pixel shown in FIG. 12 . A plurality of storage lines 131 extending approximately parallel to the gate lines 121 and made of the same material as the gate lines are formed on the substrate 110 . The gate line 121 and the storage line 131 are located near the boundary of the pixel row, and the pixel electrodes 190 and TFTs are symmetrically arranged with respect to the storage line 131 . The storage line 131 overlaps adjacent pixel electrodes 190 to form a plurality of storage capacitors.

15 to 18, the pixel electrode 190 overlaps the gate line 121 and the data line 171 to provide a large aperture ratio.

Although the preferred embodiments of the present invention have been described in detail above, those skilled in the art should understand that there will be many changes or improvements on the basis of the principles of the present invention, and these changes or improvements all belong to the appended claims. within the spirit and scope of the present invention.

Claims (14)

1. A liquid crystal display, comprising: a first insulating substrate; A plurality of thin film transistors formed on the first insulating substrate; A protection layer formed on the thin film transistor and having protrusions; a plurality of pixel electrodes formed on the protective layer and connected to the thin film transistor; a second insulating substrate facing the first insulating substrate; A black matrix formed on the second insulating substrate and defining red, green, blue and white pixels; red, green and blue color filters formed substantially in the red, green and blue pixels, respectively; a common electrode formed on the color filter; and a liquid crystal layer sandwiched between the first insulating substrate and the second insulating substrate, Wherein, the height of the common electrode is smaller in the white pixels than in the red, green and blue pixels, and the protrusions in the protection layer face the white pixels. 2. The liquid crystal display of claim 1, wherein the distance between the common electrode and the surface of the protective layer is substantially uniform. 3. The liquid crystal display of claim 1, wherein the pixel electrode and the common electrode have cutouts. 4. The liquid crystal display according to claim 1, further comprising a plurality of gate lines extending in a row direction for delivering gate signals to pixels; and a plurality of data lines extending in column directions for delivering data signals to pixels, where blue and white pixels are adjacent to each other, a pair of red pixels are diagonally facing each other across blue pixels and white pixels, and a pair of green pixels are diagonally facing each other across blue pixels and white pixels and are opposite to red Pixels are adjacent. 5. The liquid crystal display according to claim 4, wherein the relative positions of the blue pixels and the white pixels in two adjacent groups of pixels in the column direction or in the row direction are reversed. 6. The liquid crystal display of claim 4, wherein the pixels have a rectangular shape, and the blue pixels and the white pixels are arranged in a column direction to form separate columns. 7. The liquid crystal display of claim 4, wherein the blue pixel and the white pixel have a triangular shape to form a rhombus. 8. The liquid crystal display of claim 7, wherein a boundary line between the blue pixel and the white pixel extends in a row direction or a column direction. 9. The liquid crystal display according to claim 4, wherein the red pixels in two adjacent columns are located in different rows, and the red pixels in adjacent rows are located in different columns, wherein the green pixels in two adjacent columns are located in In different rows, the green pixels in adjacent rows are located in different columns, and the blue or white pixels in two adjacent groups of pixels in the row direction are located in different rows, or in two adjacent groups in the column direction The blue or white pixels in are in different columns. 10. The liquid crystal display of claim 4, wherein the liquid crystal display is driven by drawing. 11. The liquid crystal display of claim 1, further comprising a transparent organic color filter formed substantially in the white pixels. 12. The liquid crystal display of claim 11, further comprising a coating between the color filter and the common electrode. 13. The liquid crystal display of claim 12, wherein the transparent organic color filter comprises the same material as the coating layer. 14. A liquid crystal display according to claim 12, wherein the surface of the coating has a substantially uniform height.

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