KR20060099080A - Liquid crystal display device - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device which prevents moire phenomenon of a display screen by improving a structure of a black matrix provided in the liquid crystal panel. According to the present invention, there is provided a liquid crystal panel comprising a black matrix formed to distinguish between sub color filters of RGB and block light; And a backlight unit including a light source, a reflection sheet, a light guide plate, a diffusion sheet, and a prism sheet for applying light to the liquid crystal panel, wherein the prism sheet is formed with a valley formed in a first direction. And a second sheet having a valley formed in a direction perpendicular to the first sheet and the first direction, wherein the black matrix has an acute angle of 10 ° to 80 ° among the angles formed with the valleys formed in the first sheet and the second sheet. It has a plurality of tips throughout the edge to have.

Description

Liquid crystal display device

1 is a view for explaining a prism sheet of a liquid crystal display device.

2 is a view for explaining a conventional liquid crystal display device.

3 to 5 are views for explaining a liquid crystal display device according to the present invention.

Explanation of symbols on the main parts of the drawings

10,11,12: prism sheet 13: liquid crystal panel

21,22,32,33,42,43,52,53: goal of prism sheet

20,30,40,50: black matrix 23,34,44,54: screen display area

31,41,51: tips

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device which improves a structure of a black matrix provided in a liquid crystal panel to prevent moire phenomenon of a display screen.

The liquid crystal display device applies an electric field to the liquid crystal interposed between the two substrates, and adjusts the intensity of the electric field to adjust the amount of light transmitted through the substrate to obtain an image signal desired by the user. Unlike the CRT, since the LCD is not a display device that emits light by itself, it requires a separate light source for visually representing an image on the back of the liquid crystal panel. To this end, the liquid crystal display includes a liquid crystal panel in which liquid crystal cells are arranged in a matrix to display an image, a driving device for driving the liquid crystal panel, and a back light for applying light to the liquid crystal panel. .

The liquid crystal panel has a structure in which an array substrate on which a thin film transistor and a pixel electrode are formed, and a color filter substrate on which a black matrix, sub color filters R, G, and B, and a counter electrode are formed are bonded to each other through a liquid crystal layer. In addition, the backlight is provided with a light source, a light guide plate spaced apart from the side of the light source to transmit the light from the light source to the liquid crystal panel, a lamp reflector surrounding the light source, and a rear surface of the light guide plate to fall into the back of the light guide plate. And a reflecting sheet for returning the emitted light back to the light guide plate, and a diffusion sheet, a prism sheet, and a protective sheet which are sequentially installed on the front surface of the light guide plate. The driving device may include a gate driver for driving gate lines of the liquid crystal panel, a data driver for driving data lines, a timing controller for supplying timing control signals and pixel data to the gate driver and the data driver, and a power supply voltage. It includes a power supply.

As shown in FIG. 1, the prism sheet included in the backlight of the liquid crystal display device includes a first sheet 11 having valleys in the x direction and a second sheet 12 having valleys in the y direction. Alternatively, only one of the two sheets 11 and 12 may be provided. In addition, the light guide plate may be provided with a prism light guide plate in which a valley in the x direction or the y direction is formed, that is, a prism pattern is formed. Hereinafter, the prism sheet will be described with the first sheet 11 having a valley formed in the x direction and the second sheet 12 having a valley formed in the y direction.

The prism sheet 10 collects light diffused from the diffusion sheet (not shown) and spreads out of the viewing angle to increase luminance, and transmits the light to the liquid crystal panel 13. Here, the arrow shows the emission direction of light. When the light applied to the liquid crystal panel 13 passes through pixel electrodes connected to the thin film transistors and passes through RGB sub-color filters corresponding to the pixel electrodes, the liquid crystal display displays a color image desired by the user. At this time, the black matrix, which distinguishes between the sub-color filters and serves as a light blocking function, meets the valleys formed in the x and y directions of the freeze sheet 10. As a result, a moire phenomenon occurs in which a stripe occurs on the display screen of the liquid crystal display, and a conventional liquid crystal display has a problem in that the image quality of the display screen is deteriorated.

The moiré phenomenon is a phenomenon caused by the interference between the moire shadow mask and the scanning line, and the degree varies depending on the angle formed between the black matrix and the valleys in the x and y directions of the freeze sheet 10. . That is, the smaller the angle formed between the valley of the prism sheet 10 and the black matrix, the greater the interference caused by diffraction, and as a result, the moiré phenomenon occurs more severely. In particular, the moiré phenomenon is severely caused by the angle formed between the first sheet 11 having a valley formed in the x direction and the black sheet having the first sheet 11 disposed above the second sheet 12 having a valley formed in the y direction. Occurs. Therefore, the degree of occurrence of the moire phenomenon is determined according to the angle formed between the bone formed in the x direction of the first sheet 11 and the black matrix. In addition, when the prism sheet 10 includes only one sheet of two sheets 11 and 12, the degree of occurrence of the moiré phenomenon is determined according to the angle formed between the black matrix and the valley formed on the sheet having the sheet. do. In addition, when the liquid crystal display includes a prism light guide plate, a moiré phenomenon occurs due to an angle formed between the prism pattern formed on the prism light guide plate and the black matrix.

In order to reduce the moiré phenomenon, a method of changing the angle formed between the valley of the prism sheet 10 and the black matrix by varying the angle of the prism sheet 10 has been proposed. For example, as illustrated in FIG. 2, the angle of the first sheet having the valleys 21 formed in the x direction among the first and second sheets having the valleys 21, 22 formed in the x and y directions is determined with respect to the x direction. A method of varying about 5 ° has been proposed. Accordingly, as the acute angle a becomes about 5 degrees among the angles formed between the valleys 21 and the black matrix 20 of the first sheet, the interference of light due to diffraction of the screen display area 23 is reduced. The moiré phenomenon of the display screen can be reduced. However, the above method has a problem in that the manufacturing cost of the liquid crystal display device increases as the angle of the prism sheet is varied.

Accordingly, the present invention was created to solve the problems inherent in the liquid crystal display device according to the prior art as described above, and an object of the present invention is to improve the structure of the black matrix to prevent the occurrence of the moiré phenomenon to improve the image quality of the display screen. It is to provide a liquid crystal display device that can be improved.

In order to achieve the above object, according to an aspect of the present invention, a liquid crystal panel comprising a black matrix formed to distinguish between the sub-color filters of RGB and block light; And a backlight unit including a light source, a reflection sheet, a light guide plate, a diffusion sheet, and a prism sheet for applying light to the liquid crystal panel, wherein the prism sheet is formed with a valley formed in a first direction. And a second sheet having a valley formed in a direction perpendicular to the first sheet and the first direction, wherein the black matrix has an acute angle of 10 ° to 80 ° among the angles formed with the valleys formed in the first sheet and the second sheet. It has a plurality of tips throughout the edge to have.

In the above configuration, the plurality of tips are provided to protrude in a triangular shape or concave to convex semicircular shape toward the sub color filter side of the RGB.

According to another aspect of the invention, a liquid crystal panel comprising a black matrix formed to distinguish between the sub-color filter of RGB and block light; And a backlight unit including a light source, a reflection sheet, a light guide plate, a diffusion sheet, and a prism sheet for applying light to the liquid crystal panel, wherein the prism sheet comprises a sheet having a valley formed in a predetermined direction. The black matrix may include a plurality of tips at the edge of the black matrix to have an acute angle of 10 ° or more.

In the above configuration, the plurality of tips are provided to protrude in a triangular shape or concave to convex semicircular shape toward the sub color filter side of the RGB.

According to another aspect of the invention, a liquid crystal panel comprising a black matrix formed to discriminate between the sub-color filters of RGB and block light; And a backlight unit including a light source, a reflection sheet, a prism light guide plate, and a diffusion sheet for applying light to the liquid crystal panel, wherein the prism light guide plate has a prism pattern having valleys in a predetermined direction. The black matrix may include a plurality of tips at edges of the predetermined direction such that an acute angle is greater than or equal to 10 degrees among the valleys formed in the prism light guide plate.

In the above configuration, the plurality of tips are provided to protrude in a triangular shape or concave to convex semicircular shape toward the sub color filter side of the RGB.

(Example)

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

3 is a view for explaining a liquid crystal display device according to the present invention.

In the liquid crystal display according to the present invention, the black matrix 30 which distinguishes between the sub color filters of RGB and serves as light blocking has a plurality of tips 31. In other words, the black matrix 30 of the liquid crystal display according to the present invention includes a plurality of triangular tips 31 on the entire edge of the sub-color filter side, and the plurality of tips 31 are sub-areas of RGB. It is formed to protrude toward the color filter. In addition, the plurality of tips 31 are formed only in an area overlapped between the pixel electrode (not shown) and the black matrix to prevent the aperture ratio of the display screen from being lowered, that is, the display screen area 34 is reduced. It is not formed in the region 34.

By the plurality of tips 31, the black matrix 30 is interposed between the valleys 32 formed in the x direction in the first sheet of the prism sheet provided in the backlight and the valleys 33 formed in the y direction in the second sheet. Of the angles formed, the acute angles a, b, c, and d are designed to have 10 ° to 80 °. In other words, of the acute angles a and b formed between the valley 32 formed in the x direction of the first sheet and the black matrix 30, the acute angle a formed with the x direction of the black matrix 30 is 10 °. With the above, a plurality of tips 31 are formed such that the y direction and the acute angle b formed are 80 degrees or less. Also, of the acute angles (c, d) formed between the valleys 33 formed in the y direction of the second sheet and the black matrix 30, the acute angle d formed with the x direction of the black matrix 30 is 80 ° or less. And a plurality of tips 31 are formed such that the y direction and the acute angle c formed are 10 degrees or more.

Thus, as the acute angles (a, b, c, d) formed between the valleys 32 and 33 formed in the x and y directions of the prism sheet and the black matrix 30 are 10 ° to 80 °, the valleys of the prism sheet ( Interference due to diffraction of light occurring between the 32 and 33 and the black matrix 32 is reduced. That is, in the liquid crystal display according to the present invention, the acute angles a, b, c, and d formed between the valleys 32 and 33 formed in the x and y directions of the prism sheet and the black matrix 30 are 10 ° to 80 °. By designing the black matrix 30 to have a degree of interference, the moiré phenomenon of the display screen is prevented by reducing interference due to diffraction of light.

On the other hand, when the prism sheet includes only the first sheet in which the valleys 32 are formed in the x direction, the black matrix 30 includes a plurality of tips at both edges of the x direction parallel to the valleys 32 in the x direction. do. In addition, when the prism sheet includes only the second sheet having the valleys 33 formed in the y direction, the black matrix 30 has a plurality of tips 31 at both edges in the y direction parallel to the valleys 33 in the y direction. ). In addition, when the liquid crystal display includes a prism light guide plate having a prism pattern, valleys are formed in a predetermined direction on the prism light guide plate, and the black matrix 30 has a plurality of edges in the predetermined direction parallel to the valleys in a predetermined direction. It has a tip 31 of. The plurality of tips 31 are formed to have an acute angle of 10 degrees or more among the angles formed between the valleys and the black matrix formed in each direction, and also to prevent the reduction of the display screen area 34. It is formed only in the region overlapping the liver, but is not formed in the screen display region 34. The liquid crystal display device according to the present invention is also designed to have an acute angle formed between the bone formed on the prism sheet or the prism light guide plate and the black matrix 30 to be 10 ° or more, thereby reducing interference due to diffraction of light, thereby moiruring the display screen. To prevent.

4 and 5 illustrate a liquid crystal display according to another exemplary embodiment of the present invention. Hereinafter, only portions different from those of FIG. 3 will be described.

In the liquid crystal display according to another exemplary embodiment of the present invention illustrated in FIG. 4, the black matrix 40 is different from the above exemplary embodiment in which a plurality of tips 31 provided in the black matrix 30 have a triangle. A plurality of tips 41 provided in the is formed in a convex semicircular shape. By the plurality of tips 41, the black matrix 40 is formed with a valley 42 formed in the x direction in the first sheet of the prism sheet provided in the backlight and a valley 43 formed in the y direction in the second sheet. Of the angles formed in the liver, the acute angles a, b, c, and d have 10 ° to 80 °.

In addition, in the liquid crystal display according to another exemplary embodiment of the present invention illustrated in FIG. 5, unlike the previous exemplary embodiment in which a plurality of tips 31 included in the black matrix 30 have a triangle, the black matrix The plurality of tips 51 provided in the 50 are formed in a concave semicircle shape. By the plurality of tips 51, the black matrix 50 is interposed between the valleys 52 formed in the x direction in the first sheet of the prism sheet provided in the backlight and the valleys 53 formed in the y direction in the second sheet. Of the angles formed, the acute angles a, b, c, and d have 10 ° to 80 °.

The liquid crystal display device having the black matrices 40 and 50 designed as described above may also implement the same effects as in the previous embodiment. In addition, when the prism sheet includes only the first sheet in which the valleys 42 and 52 are formed in the x direction, or only the second sheet in which the valleys 43 and 53 are formed in the y direction, the black matrix 40 and 50 may be formed. By providing a plurality of tips 41 and 51 at edges parallel to each direction, the same effect as in the previous embodiment can be realized. In addition, when the liquid crystal display includes a prism light guide plate having a prism pattern, the black matrices 40 and 50 have a plurality of tips 41 and 51 at edges parallel to the valley direction of the prism pattern. The effect can be implemented equally. That is, the liquid crystal display according to the present invention includes a plurality of tips 31, 41, and 51 having a predetermined shape at the edges of the black matrices 30, 40, and 50 in a direction parallel to the direction of the valley formed in the prism sheet or the prism pattern. By reducing the interference by light diffraction, the moiré phenomenon of the display screen is prevented.

According to the above-described configuration of the present invention, the quality of the display screen can be improved by improving the structure of the black matrix to prevent occurrence of moiré phenomenon.

While the invention has been shown and described with reference to specific embodiments, the invention is not so limited, and it is to be understood that the invention is capable of various modifications without departing from the spirit or field of the invention as set forth in the claims below. It will be readily apparent to one of ordinary skill in the art that modifications and variations can be made.

Claims (6)

A liquid crystal panel comprising a black matrix formed to distinguish between the sub color filters of RGB and block light; A liquid crystal display device comprising: a backlight unit including a light source for applying light to the liquid crystal panel, a reflective sheet, a light guide plate, a diffusion sheet, and a prism sheet. The prism sheet includes a first sheet having a valley formed in a first direction and a second sheet having a valley formed in a direction perpendicular to the first direction, The black matrix is a liquid crystal display, characterized in that it comprises a plurality of tips (tips) on the entire edge so that the acute angle of the angle formed between the valleys formed on the first sheet and the second sheet and the angle formed from 10 ° to 80 °. The method of claim 1, And the plurality of tips are provided to protrude in a triangular shape or concave to convex semicircular shape toward the sub-color filter side of the RGB. A liquid crystal panel comprising a black matrix formed to distinguish between the sub color filters of RGB and block light; A liquid crystal display device comprising: a backlight unit including a light source, a reflection sheet, a light guide plate, a diffusion sheet, and a prism sheet for applying light to the liquid crystal panel. The prism sheet has a sheet formed with a valley in a predetermined direction, The black matrix is a liquid crystal display, characterized in that a plurality of tips on the edge so that the acute angle of the valley formed in the sheet and the angle formed to have more than 10 °. The method of claim 3, wherein And the plurality of tips are provided to protrude in a triangular shape or concave to convex semicircular shape toward the sub-color filter side of the RGB. A liquid crystal panel comprising a black matrix formed to distinguish between the sub color filters of RGB and block light; A liquid crystal display device comprising: a backlight unit including a light source for applying light to the liquid crystal panel, a reflection sheet, a prism light guide plate, and a diffusion sheet. The prism light guide plate has a prism pattern in which valleys are formed in a predetermined direction, And the black matrix has a plurality of tips at edges of the predetermined direction such that an acute angle is greater than 10 degrees among valleys formed in the prism light guide plate. The method of claim 5, wherein And the plurality of tips are provided to protrude in a triangular shape or concave to convex semicircular shape toward the sub-color filter side of the RGB.

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