KR20100054242A - Liquid ctystal display device - Google Patents

Abstract

PURPOSE: An LCD(Liquid Crystal Display) device is provided to improve display quality by enhancing entire brightness and chromatic purity. CONSTITUTION: A pixel includes red, green, blue and white sub pixels, and the area ratio of the each sub-pixel is 0.85:0.9:0.75:0.5 in order from red to white. Each sub-pixel is arranged in one direction, and displays red, green, white and blue colors in order.

Description

Liquid crystal display device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a vertical stripe type liquid crystal display device in which one pixel is composed of four subpixels.

Cathode ray tube (CRT), one of the widely used display devices, has been mainly used for monitors such as TVs, measuring devices, information terminal devices, etc., but due to the large weight and size of CRT itself, It could not respond actively to the demand for weight reduction.

In order to replace the CRT, a liquid crystal display device having advantages of small size and light weight has been actively developed. Recently, the liquid crystal display device has been developed enough to perform a role as a flat panel display device, and its demand is gradually increasing.

The image realization principle of the liquid crystal display device uses the optical anisotropy and polarization property of the liquid crystal. The liquid crystal has a thin and long molecular structure and polarization in which the direction of the molecular array changes depending on its size when placed in an electric field and an anisotropy having an orientation in the array. It has a nature.

The liquid crystal display is an essential component of a liquid crystal panel composed of a pair of transparent insulating substrates, each having a liquid crystal layer interposed therebetween, and having a field generating electrode formed therebetween. Various images are displayed by artificially adjusting the arrangement direction of the molecules and using the light transmittance which is changed at this time.

The liquid crystal panel 10 includes a liquid crystal layer and first and second substrates bonded side by side with the liquid crystal layer interposed therebetween, and an array element for driving the liquid crystal is provided on an inner surface of the first substrate called an array substrate. This is because a plurality of gate lines GL and data lines DL are arranged to define a pixel P having a matrix form, and a thin film transistor T is provided at each crossing point to each pixel P. It is connected one-to-one with the formed pixel electrode.

The second substrate, also called a color-filter substrate, includes a color filter for color realization, a color filter element such as a common electrode facing the pixel electrode with a liquid crystal layer interposed therebetween. .

1A to 1B are plan views schematically illustrating pixel arrays of a general liquid crystal display device.

As shown in Fig. 1A, R (red), G (green), and B (blue) sub-pixels defined by crossing the gate wiring and the data wiring are defined, where the sub-pixels are sequentially arranged in the horizontal row direction. It consists of a vertical stripe (vertical stripe) method arranged in.

Three subpixels R, G, and B form one pixel.

Alternatively, as shown in FIG. 1B, a quad method in which a subpixel of white (W) is added to three subpixels of R, G, and B so that four subpixels form one pixel is recently used.

The subpixels of R, G, B, and W are arranged in row and column directions in a matrix form in the same area.

The quad method adds W subpixels to the three R, G, and B subpixels to form one pixel, thereby achieving higher white luminance than a liquid crystal display using only three R, G, and B subpixels. You can get it.

On the other hand, in the quad method, since the area occupied by each of the R, G, B, and W subpixels is the same, the area occupied by the W subpixels corresponds to 25% of the total.

As a result, the white luminance of the liquid crystal display increases, but the luminance of the pure colors of the R, G, and B colors itself is lowered due to the decrease in the area of the R, G, and B subpixels. In particular, a dark yellow phenomenon occurs, in which a decrease in color of yellow that is easily perceived by a human eye is significantly reduced.

In addition, there is a problem in that the image quality is degraded by increasing the difference between the gray color and the white color due to the increase in the white luminance.

In particular, in recent years, as the resolution is increased, the text is to be displayed as a clear type. The clear type is to display the text smoothly. By shading.

However, since the clear type is applied only to the vertical stripe type structure, the clear type is not implemented because the structure of the pixel is different in the conventional quad methods of R, G, B, and W.

As shown in FIG. 2, when the text "H" is to be expressed as a clear type, the vertical line appears to be fuzzy.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and a first object of the present invention is to improve display quality by appropriately adjusting the balance between luminance and color purity by increasing luminance as a whole and increasing color purity of R, G, and B colors. .

Another object is to provide a clear liquid crystal display device.

In order to achieve the above object, a liquid crystal display device in which red, green, blue, and white sub-pixels constitute one pixel, wherein the area ratio of each sub-pixel is The red, the green, the blue, and the white subpixels are provided in the order of 0.85: 0.9: 0.75: 0.5.

Each subpixel is disposed in one direction, and each subpixel sequentially displays colors of red, green, white, and blue.

In addition, each of the subpixels sequentially displays colors of red, white, green, and blue, and the subpixels of pixels adjacent to the one pixel It is characterized by being shaded.

As described above, according to the present invention, a feature of the present invention is that R, G, B subpixels are formed larger than W subpixels for the area occupied by each of the R, G, W, and B subpixels forming one pixel. As a result, the overall luminance is increased, and the color purity of the R, G, and B colors is increased, so that the balance between the luminance and the color purity can be appropriately adjusted.

As a result, the display quality can be improved, and the clear text can be implemented.

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

3 is an exploded perspective view of a liquid crystal display according to an exemplary embodiment of the present invention.

As shown in the figure, a liquid crystal panel 110 having an array substrate and a color filter substrate bonded to each other with a liquid crystal layer 150 interposed therebetween, and a backlight assembly disposed thereunder. 160 has a configuration.

A plurality of data lines 212 and gate lines 216 cross each other on one surface of the first substrate 112, called a lower substrate or an array substrate, to define sub-pixels.

The thin film transistor T is provided at the intersection point of these two lines and is connected one-to-one with the transparent pixel electrode 220 provided in each subpixel SP.

In addition, the second substrate 114 facing the liquid crystal layer 150 therebetween is called an upper substrate or a color filter substrate, and one surface thereof has a data line 212 of the first substrate 112. A grid-like black matrix 232 is formed around the subpixels to expose only the pixel electrode 220 while covering the non-display elements such as the gate line 216 and the thin film transistor T.

In addition, R (red), G (green), W (white), and B (blue) color filters 234 sequentially arranged to correspond to each subpixel in the lattice, and a transparent common electrode covering all of them. 236).

In addition, although not clearly shown in the drawings, the upper and lower alignment layers for determining the initial molecular alignment direction of the liquid crystal are interposed between the two substrates 112 and 114 and the liquid crystal layer 150, and the liquid crystal filled therebetween. Seal patterns are formed along the edges of both substrates 112 and 114 to prevent leakage of the layer 150, and only specific light is selectively selected as an outer surface of the first and second substrates 112 and 114. A polarizing plate to transmit through may be attached.

In addition, since the first substrate 112 has a larger area than the second substrate 114, one side edge of the first substrate 112 is exposed to the outside when the two substrates 114 are bonded to each other. A plurality of data pads 214 connected to each other and a plurality of gate pads (not shown) connected to the plurality of gate lines 216 are positioned.

Accordingly, the on / off signal of the thin film transistor T is sequentially scanned and applied to the gate line 26 so that an image of the data line 212 is applied to the pixel electrode 220 of the selected sub-pixel SP. When the signal is transmitted, the liquid crystal molecules are driven by the vertical electric field therebetween, and various images can be displayed by the change in the transmittance of light.

In this case, the liquid crystal panel 110 according to the present invention has four subpixels (SP: hereinafter referred to as R, G, W, and B subpixels) corresponding to each of the R, G, W, and B color filters 234. One pixel is formed, and each of the sub-pixels SP is formed in a vertical stripe method that is sequentially arranged in a horizontal row direction.

In particular, the areas occupied by each of the R, G, W, and B subpixels SP of the present invention are different from each other. For this reason, it is possible to appropriately adjust the balance of luminance and color purity by increasing the overall luminance and increasing the color purity of the R, G, and B colors.

Through this, the display quality can be improved.

In addition, a clear type text may be implemented, which will be described in more detail with reference to FIG. 4.

4 is a plan view schematically illustrating the pixel array of FIG. 3.

As shown in the drawing, a vertical stripe type liquid crystal display device converts R, G, and B subpixels into W subpixels for four subpixels forming one pixel, that is, R, G, W, and B subpixels. To form larger than.

Therefore, the area occupied by the W subpixels can be formed to be 25% or less of the total openings.

In more detail, for the convenience of description, the area of each subpixel positioned in one pixel will be defined as R1, G1, W1, and B1.

Therefore, the index B color, which is the most insensitive to the change of light quantity among the three colors of R, G, and B, has the least effect on the image quality due to the reduction of the area. In order to compensate for yellow), the areas R1 and G1 of the R subpixels and the G subpixels forming yellow are wider than the area B1 of the B subpixel.

The area W1 of the W subpixel is formed smaller than the area B1 of the B subpixel.

That is, the area of each subpixel is formed to satisfy the formula of R1 = G1> B1> W1.

At this time, in order to maintain the color coordinate of yellow, the areas R1 and G1 of the R subpixel and the G subpixel are equal to each other.

In addition, it is preferable not to form the area B1 of the B subpixel too small compared with the areas R1 and G1 of the R subpixel and the G subpixel. This results in yellowish, in which the full white is displayed close to yellow when the area B1 of the B subpixel is too small for the areas R1 and G1 of the R subpixel and the G subpixel. Because I can.

Therefore, by further adding W subpixels to the three R, G, and B subpixels to form one pixel, when the light emitted from the backlight (160 in FIG. 3) passes through the W subpixels, the luminance is not affected. Since almost 100% of light passes through it, the overall brightness increases.

At the same time, the area R1, G1, and B1 of the R subpixel, G subpixel, and B subpixel are formed larger than the area W1 of the W subpixel to increase the color purity of the existing R, G, and B colors themselves. do.

As a result, it is possible to prevent the dark yellow phenomenon from occurring and to prevent the problem of deterioration of the image quality due to a severe difference between the gray color and the white color due to the increase in the white luminance.

Hereinafter, referring to Table 1, it will be determined whether the color coordinates change according to the relationship of the area (R1, G1, B1, W1) of the R, G, W, and B subpixels.

white red green blue yellow Contrast Ratio x y Y x y x y x y x y Y sample 1 0.324 0.338 102 0.578 0.359 0.363 0.559 0.159 0.142 0.445 0.483 84 82.40% sample 2 0.320 0.330 132 0.578 0.358 0.357 0.564 0.159 0.141 0.443 0.484 57 43.20% sample 3 0.328 0.344 126 0.578 0.359 0.361 0.560 0.159 0.140 0.441 0.486 72 57.10%

TABLE 1

Here, sample 1 is a vertical stripe pixel array consisting of general R, G, and B subpixels, and sample 2 is a quarter pixel array consisting of R, G, B, and W subpixels, and sample 3 is a pixel array of the present invention. According to the exemplary embodiment, the pixel arrays of the vertical stripe type have different areas of the R, G, B, and W subpixels.

At this time, the area of each subpixel of Sample 3 has a ratio of R1: G1: B1: W1 = 0.85: 0.9: 0.75: 0.5.

In addition, x and y are coordinates on the color coordinate of each color, and Y represents the luminance of the color.

As can be seen from Table 1, sample 3, which is a vertically arranged pixel array of R, G, W, and B subpixels having an asymmetrical area of the present invention, has a full white luminance of 126 to 102. You can see that it is higher than that.

In addition, the quarter sample 2 has a lower color reproducibility and contrast ratio than the sample 1 of R, G, and B, which is a vertically arranged pixel array of R, G, B, and W subpixels having an asymmetrical area of the present invention. Sample 3 shows that the color reproducibility is similar to sample 1.

In addition, it can be seen that the contrast ratio is higher than the sample 2, the contrast ratio of the sample 3 of the present invention can be seen that improved by more than 33% compared to the sample 2.

That is, in the vertical stripe pixel array formed of the R, G, W, and B subpixels of the present invention, the area R1, G1, B1, W1 of each subpixel is formed differently, and thus the existing R, G, B vertical star is formed. It has higher luminance than the life pixel array, and has higher color reproduction and contrast ratio than the conventional R, G, B, and W quarter methods.

Table 2 below shows the ratios of the area (R1, G1, B1, W1) of the R, G, W, B subpixels of the vertically striped pixel array of the R, G, W, B subpixels having the asymmetrical area of the present invention. Simulation results measured differently.

TABLE 2

Here, sample 1 is a vertical stripe pixel array consisting of general R, G, and B subpixels, and sample 2 is a quarter pixel array consisting of R, G, B, and W subpixels, and sample 3 is a pixel array of the present invention. According to the exemplary embodiment, the pixel arrays of the vertical stripe type have different areas of the R, G, W, and B subpixels.

Looking at Table 2, each subpixel

In the case of arranging at an area ratio of R1: G1: B1: W1 = 0.95: 0.95: 0.5: 0.6,

The color coordinate of white is much different from that of white of sample 1, so that the luminance of full white is 135 and the luminance of yellow is 78.

As a result, the luminance value of yellow has a very high value compared to the luminance of full white, resulting in yellowishness of full white.

However, each subpixel

R1: G1: B1: W1 = 0.85: 0.9: 0.74: 0.5, when arranged in the area ratio

The luminance of full white is much higher than that of sample 1, which is a vertically arranged pixel array consisting of R, G, and B subpixels, and the color reproducibility is most similar to that of other pixel arrays having different area ratios.

In particular, the color coordinates of white that implements full white are the most similar to sample 1. Thus, yellowing is low due to visually sensitive white luminance, and yellowing does not occur.

Therefore, it is preferable that the area of each subpixel has an area ratio of R1: G1: B1: W1 = 0.85: 0.9: 0.75: 0.5.

In addition, in the vertical stripe type liquid crystal display of the present invention, four subpixels forming one pixel are sequentially arranged in the order of R, G, W, and B subpixels, thereby providing a clear type. Can represent text.

5A and 5B illustrate clear type text according to an embodiment of the present invention.

Here, the clear type is to display text smoothly when the text is to be represented, as shown in the figure, by driving each sub-pixel individually and shading adjacent sub-pixels according to the situation.

That is, as shown in FIG. 5A, when one pixel is composed of R, G, B, and W subpixels, since the subpixels adjacent to the pixels are R or B, the adjacent pixels R or B are shaded when the clear type is applied. To deal with.

In particular, in the vertical stripe liquid crystal display of the present invention, four sub-pixels forming one pixel are sequentially arranged in the order of R, G, W, and B sub-pixels, whereby the R sub is relatively low in luminance. Pixels and B sub-pixels can be combined more naturally with the shaded side pixels, respectively.

Here, the positions of the G subpixels and the W subpixels may be interchanged with each other.

5B is a diagram illustrating clear type text according to an arrangement of sub-pixels.

Here, sample 1 is a vertical stripe pixel array consisting of general R, G, and B subpixels, and sample 2 is a quarter pixel array consisting of R, G, B, and W subpixels, and sample 3 is a pixel array of the present invention. According to an exemplary embodiment, the pixel array is a vertical stripe pixel array including subpixels sequentially arranged in the order of R, G, W, and B. FIG.

Sample 4 is a vertical stripe pixel array consisting of subpixels sequentially arranged in the order of R, G, B, and W. FIG.

As shown, in the quad method of R, G, B, and W, since the structure of the pixels is different, the vertical lines become more prominent when the vertical lines are represented, and the vertical lines appear fuzzy.

In addition, the vertical stripe type liquid crystal display device sequentially arranged in the order of R, G, B, and W subpixels is used when the B subpixels of the subpixels adjacent to one pixel need to be shaded. This makes the vertical line appear in two rows.

However, according to an exemplary embodiment of the present invention, the vertically arranged pixel array in which the pixels are sequentially arranged in the order of R, G, W, and B has the adjacent pixels in which the R subpixels and the B subpixels having relatively low luminance are shaded, respectively. This allows for a more natural combination of the two, so that you can implement text of the clear type most similar to sample 1.

In this case, the luminance is much higher than sample 1, and also has a higher color reproduction ratio and contrast ratio than sample 2 of the quarter method.

As described above, the area of the R, G, and B subpixels is set to the area of the W subpixel with respect to the areas R1, G1, B1, and W1 occupied by each of the R, G, W, and B subpixels forming one pixel. By forming larger than that, it is possible to increase the overall luminance and at the same time increase the color purity of the R, G, and B colors so as to appropriately adjust the balance between the luminance and the color purity.

Through this, display quality can be improved and clear type text can be implemented.

The present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention.

1A to 1B are plan views schematically illustrating pixel arrays of a general liquid crystal display device.

2 is a diagram schematically illustrating a state in which a clear type is applied to a quad pixel pixel array;

3 is an exploded perspective view of a liquid crystal display according to an exemplary embodiment of the present invention.

4 is a plan view schematically illustrating a pixel array of FIG. 3.

5A to 5B are diagrams for explaining clear type text according to an embodiment of the present invention;

Claims (5)

A red, green, blue, and white subpixel is a liquid crystal display device comprising one pixel. The area ratio of each subpixel is 0.85: 0.9: 0.75: 0.5 in order of the red, the green, the blue, and the white subpixels. Liquid crystal display device. The method of claim 1, And each sub-pixel is disposed in one direction. The method of claim 1, Wherein each of the subpixels sequentially displays colors of red, green, white, and blue. The method of claim 1, Wherein each of the subpixels sequentially displays colors of red, white, green, and blue. The method of claim 1, And sub-pixels of pixels adjacent to the one pixel are shaded.

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