KR100805539B1 - Back light unit of light guide plate and liquid crystal display device having same - Google Patents

Abstract

The present invention relates to a light guide plate and a backlight unit of a liquid crystal display device having the same, and more particularly, to a light guide plate and a liquid crystal display device using the same to prevent the generation of bright lines and to improve the brightness of the display. A liquid crystal display according to the present invention includes a light guide plate including a light source emitting light, an incident surface on which light emitted from the light source is incident, and one surface on which the incident light is emitted, and disposed at a position facing the one surface of the light guide plate. And a prism sheet disposed on an opposite surface of the diffusion sheet and a surface facing the light guide plate of the diffusion sheet, and the other surface facing the one surface of the light guide plate includes a plurality of V-shaped grooves each having a first inclined surface and a second inclined surface. The first inclined surface is formed to be inclined by the range of 8 ° or more and 30 ° or less from the one surface.

LCD, LGP, Serrated Pattern, Bright Line, Prism

Description

Light guide panel and back light unit of liquid crystal display device having the same}

1 is an exploded perspective view showing a conventional liquid crystal display device.

2 is an exploded perspective view showing an example of a liquid crystal display according to the present invention.

3 is a cross-sectional view showing a backlight according to the present invention.

4 is a perspective view illustrating a bottom surface of the light guide plate employed in FIG. 3.

5 is a photograph of a liquid crystal display device showing the effect of the present invention.

6A and 6B are graphs showing effect data according to the present invention.

*** Description of the main symbols in the drawings ***

300: light guide plate 300c: other surface

300a: incident surface 301: first inclined surface

300b: one side 302: second inclined surface

The present invention relates to a light guide plate and a backlight unit of a liquid crystal display device using the same, and more particularly, to a light guide plate and a backlight unit of the liquid crystal display device using the same to prevent the generation of bright lines and to improve the brightness of the display.

 As the information and communication industry is rapidly developed, the use of display devices is rapidly increasing, and in recent years, display devices capable of satisfying conditions of low power, light weight, thinness, and high resolution are required. In response to these demands, display devices using liquid crystal displays or organic light emitting characteristics have been developed.

Thin Film Transistor-Liquid Crystal Display (TFT-LCD), which has excellent color reproducibility, low power consumption, and is made thin, is one of the most widely used flat panel display devices. The liquid crystal display panel includes a liquid crystal display panel into which liquid crystal is injected, a backlight unit used under a liquid crystal display panel, and a driving unit for driving the liquid crystal display panel.

1 is an exploded perspective view showing a conventional liquid crystal display device.

Referring to FIG. 1, a conventional liquid crystal display device includes a liquid crystal display panel 10 on which an image is displayed and a backlight unit 30 for providing light to the liquid crystal display panel 10.

The liquid crystal display panel 10 includes two substrates disposed to face each other, a liquid crystal layer interposed between the two substrates, and a pixel region is formed by a plurality of gate lines and data lines arranged in a matrix form on the substrate. Is defined. A thin film transistor for controlling a signal supplied to each pixel and a pixel electrode connected to the thin film transistor are formed on a substrate where the gate line and the data line cross each other, and a color filter and a common electrode are formed on the other substrate.

The backlight unit 30 may include a light guide plate that emits light, a predetermined pattern, for example, a dot pattern, to change the distribution of light provided from the light source 32 and provide the light guide plate 10 to the liquid crystal display panel 10. 31) and an optical sheet 34 which makes the luminance distribution of the light provided from the light guide plate 31 uniform and improves vertical incidence, and a reflective sheet which reflects the light emitted to the light guide plate 31 to the rear of the light guide plate 31. It consists of 33.

The light source 32 is composed of a lamp 32a disposed on the side of the light guide plate 31, and a reflecting plate 32b for reflecting light emitted from the lamp 32a to the light guide plate 31, and the optical sheet 34 is A diffusion sheet 34a for diffusing light incident from the light guide plate 31 toward the liquid crystal display panel 10 and a prism sheet 34b for condensing the diffused light to improve vertical incidentness.

As described above, in the conventional liquid crystal display device, the optical sheet 34 is generally composed of one diffusion sheet 34a and two prism sheets 34b, which causes a problem that the backlight unit has a thick thickness and low luminance. Improvement efforts have been made.

An object of the present invention for solving the above-described problems is to provide a light guide plate and a backlight unit of the liquid crystal display device using the same to prevent the generation of bright lines, to improve the brightness of the display.

One aspect of the present invention for achieving the above object is a light guide plate including a light source for emitting light, an incident surface to which the light emitted from the light source is incident and one surface to which the incident light is emitted, facing the one surface of the light guide plate And a prism sheet disposed on an opposite surface of the diffusion sheet disposed in a position to face the light guide plate of the diffusion sheet, and the other surface facing the one surface of the light guide plate includes a plurality of first inclined surfaces and a second inclined surface. A sawtooth pattern is formed, and the first inclined surface is provided with a liquid crystal display device inclined by a range of 8 ° or more and 30 ° or less from the one surface.

According to another aspect of the present invention, a light guide plate including one surface from which light emitted from a light source is emitted, the first inclined surface formed on the other surface opposite to the one surface inclined by a range of 8 ° or more and 30 ° or less from the one surface and the The present invention provides a light guide plate having a plurality of V-shaped grooves including a plurality of first inclined surfaces and a second inclined surface inclined at a predetermined angle.

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

2 is an exploded perspective view showing an example of a liquid crystal display according to the present invention, Figure 3 is a cross-sectional view showing a backlight according to the present invention, Figure 4 is a perspective view showing a lower surface of the light guide plate employed in the backlight according to the present invention.

2 to 4, the liquid crystal display according to the present invention includes a liquid crystal display panel 100 and a backlight unit 200.

The liquid crystal display panel 100 includes two substrates (not shown) disposed to face each other, and a liquid crystal layer (not shown) interposed between the two substrates, and a plurality of scan lines arranged in a matrix form on the substrate. Pixel regions are defined by (not shown) and data lines (not shown). In addition, a thin film transistor for controlling a signal supplied to each pixel (not shown) and a pixel electrode connected to the thin film transistor are formed on a substrate where the scan line and the data line cross each other, and a color filter and a common electrode are formed on another substrate. Is formed.

The backlight unit 200 includes a light guide plate 300, a prism sheet 400, a diffusion sheet 500, and a reflective sheet 600.

The light guide plate 300 is disposed such that one surface 300b faces the lower surface of the liquid crystal display panel 100. In addition, a plurality of V-shaped grooves 303 formed of the first inclined surface 301 and the second inclined surface 302 are formed on the other surface 300c facing the one surface 300b of the light guide plate 300, and the first inclined surface ( The 301 is formed to be inclined by a range (a) of 8 ° or more and 30 ° or less from one surface 300b. Here, one surface 300b refers to a light exit surface from which light is emitted, and the other surface 300c refers to a reflection surface from which light incident from the light source 310 is reflected to the light exit surface.

The V-shaped groove 303 is a structure for reflecting light incident from the incident surface 300a toward the output surface 300b. On the other hand, the length of the first inclined surface 301 is formed longer than the length of the second inclined surface 302. In addition, the second inclined surface 302 is formed in the range (c) of 20 degrees or more and 70 degrees or less from the reflective surface 300c, and the first inclined surface 301 of the V-shaped groove 303 from the reflective surface 300c. The depth d to the vertex 304 where the second inclined surface 302 meets is preferably formed in the range of 2 μm to 10 μm. The plurality of V-shaped grooves 303 may be formed in an intaglio or embossed form, and are formed at densely spaced intervals away from the light source 310b.

On the other hand, a light source unit 310 configured to surround the light source 310b by the light source reflector 310a is formed at the side of the light guide plate 300. The light irradiated from the light source 310b is received at the incident surface 300a, hits and scatters the prism pattern 303 of the light guide plate 300, and then is emitted toward the prism sheet 400 through one surface 300b.

The prism sheet 400 is disposed on an opposite side of the surface facing the light guide plate 300 of the diffusion sheet 500, and in the prism sheet 400, light transmitted through one surface 300b is scattered again to diffuse the sheet 500. Is emitted. In addition, the prism sheet 400 includes a plurality of prisms 401a orthogonal to a traveling direction of light emitted from the light source 310b, and a prism 401a of the first prism sheet 401. ), A second prism sheet 402 having a plurality of prisms 402a orthogonal to each other.

The diffusion sheet 500 is disposed at a position facing the one surface 300b of the light guide plate 300 to diffuse light incident from the light guide plate 300 toward the liquid crystal display panel 100.

The reflective sheet 600 returns the light leaked from the rear surface of the light guide plate 300 back into the light guide plate 300 to prevent loss of light.

5 is a photograph of a liquid crystal display device showing the effect of the present invention.

According to the present invention through the photo shown in Figure 5 to form a plurality of V-shaped groove consisting of the first inclined surface and the second inclined surface on the other surface of the light guide plate, the first inclined surface is inclined by a range of 8 ° to 30 ° from one surface It can confirm that the bright line and the roll dark part were removed by forming the bottom.

6A and 6B are graphs showing effect data according to the present invention.

     Referring to FIGS. 6A and 6B, when a plurality of V-shaped grooves having the above-described numerical range are formed on the other surface of the light guide plate through the graph shown in FIG. 6A, they are formed in another shape, for example, a dot shape. It can be seen that the luminance is improved than when done. In addition, in the liquid crystal display device having the light guide plate to which the shape and the numerical range according to the present invention are applied through the graph shown in FIG. 6B, the emission angle of the backlight is concentrated in the 0 ° direction, thereby increasing the overall luminance of the pixel portion. You can check it.

According to the light guide plate and the liquid crystal display device using the same according to the present invention, it is possible to prevent the bright lines and improve the brightness of the display.

Although the technical idea of the present invention has been described in detail according to the above preferred embodiment, it should be noted that the above-described embodiment is for the purpose of description and not of limitation. In addition, it will be understood by those skilled in the art that various modifications are possible within the scope of the technical idea of the present invention.

Claims (15)

Light source; A light guide plate including a surface on which light incident from the light source is emitted; A diffusion sheet disposed at a position facing the one surface of the light guide plate; And A prism sheet disposed on an opposite surface of a surface of the diffusion sheet facing the light guide plate; A plurality of V-shaped grooves each having a first inclined surface and a second inclined surface are formed on the other surface of the light guide plate opposite to the one surface, and the first inclined surface is inclined by a range of 8 ° to 30 ° from the one surface. Backlight unit of the device. The method of claim 1, And the second inclined surface is inclined from the one surface by a range of 20 ° to 70 °. The method of claim 1, And a depth from the other surface to a vertex where the first inclined surface and the second inclined surface of the V-shaped groove meet is in a range of 2 μm to 10 μm. The method of claim 1, The plurality of V-type grooves are formed to be spaced apart from each other at a tight interval as the distance from the light source. The method of claim 1, And a length of the first inclined surface is longer than that of the second inclined surface. The method of claim 1, The backlight unit of the liquid crystal display device further comprises a reflective sheet for reflecting the light emitted back to the light guide plate back to the light guide plate. The method of claim 1, And a plurality of V-shaped grooves are formed in an intaglio shape. The method of claim 1, The backlight unit of the liquid crystal display device wherein the plurality of V-shaped grooves are embossed. In the light guide plate including one surface on which the light emitted from the light source is emitted, On the other side opposite to the one side, A first inclined surface formed to be inclined by a range of 8 ° or more and 30 ° or less from the one surface; And A light guide plate having a plurality of V-shaped grooves including a second inclined surface formed to be inclined at a predetermined angle with each of the plurality of first inclined surfaces. The method of claim 9, The second inclined surface is formed to be inclined by the range of 20 ° or more and 70 ° or less from the one surface. The method of claim 9, A light guide plate having a depth from the other surface to a vertex where the first inclined surface and the second inclined surface of the V-shaped groove meet is in a range of 2 μm to 10 μm. The method of claim 9, The plurality of V-shaped grooves are formed to be spaced apart from each other at densely spaced intervals as the light source. The method of claim 9, The length of the first inclined surface is longer than the length of the second inclined surface. The method according to claim 9, The plurality of V-shaped grooves are formed in the engraved light guide plate. The method of claim 9, The plurality of V-shaped grooves are formed in the light guide plate.

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