KR20060111772A - Liquid crystal display - Google Patents

Abstract

An LCD is provided to reduce the loss of light generated at a gap between a light guiding plate and a reflective plate, thereby improving the efficiency of light, by forming a coating layer containing silver on a reflective surface of the light guiding plate. An LCD comprises an LCD panel, a light guiding plate(404) disposed on a rear surface of the LCD panel, and a light source part(407) disposed along at least one side of the light guiding plate. The light guiding plate has a light exiting surface and a light reflecting surface opposite to the light exiting surface. The light exiting surface of the light guiding plate supplies light to the LCD panel. The reflective surface of the light guiding plate has a coating layer(405) containing silver.

Description

Liquid Crystal Display {LIQUID CRYSTAL DISPLAY}

1 is an exploded perspective view of a liquid crystal display device according to a first embodiment of the present invention;

2 is a side cross-sectional view of a liquid crystal display device according to a first embodiment of the present invention;

3 is an enlarged cross-sectional view for describing an optical behavior in a liquid crystal display according to a first embodiment of the present invention.

4 is a cross-sectional view of main parts of a liquid crystal display according to a second embodiment of the present invention;

5 is a cross-sectional view illustrating main parts of a liquid crystal display according to a third exemplary embodiment of the present invention.

Explanation of Signs of Major Parts of Drawings

1 liquid crystal display 10 upper chassis

20 liquid crystal display panel 30 middle mold

40: backlight assembly 401, 402, 403: optical member

404: light guide plate 405: coating layer

406: reflector 407: lamp

408: lamp reflector 50: lower chassis

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 having improved light efficiency by enhancing reflection performance of a light guide plate reflecting surface.

The liquid crystal used in the liquid crystal display device is not a light emitting material that emits light, but a light receiving material that displays on the screen by controlling the amount of light coming from the outside, so that a separate light source for illuminating the liquid crystal panel, that is, a backlight assembly is used. in need.

The backlight assembly is classified into an edge method and a direct method according to the location where the lamp is installed. The edge method is mainly applied to a relatively small liquid crystal display device such as a laptop computer and a desktop computer monitor, and has good light uniformity, long durability life, and is advantageous for thinning a liquid crystal display device.

The edge type backlight assembly includes a light guide plate, a reflecting plate, an optical member, and a light source disposed along a side of the light guide plate.

The light guide plate is a light guide for making light supplied from a light source into a surface light source, and has a light emitting surface facing the liquid crystal panel and an light incident surface opposite to the light emitting surface. The reflector is positioned below the reflective surface of the light guide plate, and reflects the light leaked to the lower part of the light guide plate from the light guide plate from the light source to the liquid crystal panel. The optical member is disposed between the emission surface of the light guide plate and the liquid crystal display panel to improve the uniformity of brightness of light generated from the light source.

In such an edge type backlight assembly, a minute gap exists between the light guide plate and the reflecting plate. However, there is a problem that some of the light incident on the gap is lost while being reflected between the light guide plate and the reflecting plate.

Accordingly, an object of the present invention is to provide a liquid crystal display device having excellent light efficiency by reducing light loss generated in a gap between a light guide plate and a reflecting plate in an edge type backlight assembly.

The object is, according to the present invention, a liquid crystal display panel, disposed on the rear surface of the liquid crystal display panel, an emission surface for supplying light to the liquid crystal display panel and a coating layer opposite to the emission surface is formed is formed The light guide plate may include a light guide plate having a reflective surface and a light source unit disposed along at least one side of the light guide plate.

The coating layer may be formed by a sputtering method.

The coating layer is preferably formed over the entire reflective surface of the light guide plate to prevent light leaking into the lower part of the light guide plate.

On the other hand, according to the present invention, the object is disposed on the liquid crystal display panel and the rear surface of the liquid crystal display panel, the light emitting surface for supplying light to the liquid crystal display panel and the polymer material is attached to the output surface facing The liquid crystal display may include a light guide plate having a reflective surface and a light source unit disposed along at least one side of the light guide plate.

The polymer material may be attached by a laminating method.

The polymer material is preferably attached to the entirety of the reflective surface of the light guide plate because it prevents light leaking into the lower part of the light guide plate.

The polymer material may be made of polyethylene terephthalate (PET).

It is preferable that the reflective surface of the light guide plate is patterned with any one of a prism pattern, a V-cut pattern, and a dot pattern because it can effectively convert light toward the liquid crystal display panel.

It is preferable to further include a reflecting plate on the rear surface of the light guide plate to protect the coating layer or the polymer material.

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

In various embodiments, the same reference numerals are used to designate the same components, and the same components will be representatively described in the first embodiment.

Can be.

A liquid crystal display according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 3.

1 is an exploded perspective view of a liquid crystal display device according to a first embodiment of the present invention, and FIG. 2 is a side cross-sectional view of the liquid crystal display device according to the first embodiment of the present invention.

As shown in the drawing, the liquid crystal display device 1 according to the first embodiment includes a liquid crystal display panel 20 on which a screen is displayed, a backlight assembly 40 supplying light to the liquid crystal display panel 20, and a backlight assembly. The middle mold 30 for accommodating the 40 and supporting the edges of the liquid crystal display panel 20 and the wires connected to the backlight assembly 40, and the lower chassis 50 for accommodating and supporting the middle mold 30. And an upper chassis 10 coupled to the lower chassis 50 to cover the entire surface of the liquid crystal display panel 20.

 The liquid crystal display panel 20 includes the thin film transistor substrate 21, the color filter substrate 22 facing the thin film transistor substrate 21, the sealant 23 and the amount that bond the two substrates to form a cell gap. The liquid crystal layer 24 is positioned between the substrate and the sealant 23. In addition, the liquid crystal display panel 20 further includes a polarizing plate (not shown) to allow light passing through the liquid crystal display panel 20 to cross-polarize. The liquid crystal display panel 20 adjusts the arrangement of the liquid crystal layer 24 to form a screen. However, since the liquid crystal display panel 20 is a non-light emitting device, light must be supplied from the backlight assembly 40 disposed on the rear surface. In the liquid crystal display panel 20, a plurality of liquid crystal cells forming a pixel unit are arranged in a matrix form, and an image is realized by adjusting light transmittance of liquid crystal cells according to image signal information transmitted from the driver 25.

One side of the thin film transistor substrate 21 is provided with a driver 25 for applying a driving signal. The driver 25 includes a flexible printed circuit board 252, a driving chip 251 mounted on the flexible printed circuit board 252, and a circuit board 253 connected to the other side of the flexible printed circuit board 252. do. The illustrated driver 25 is a chip on film (COF) method, and other known methods such as a tape carrier package (TCP) and a chip on glass (COG) may be used, and the driver 25 may include a thin film transistor substrate ( It is also possible to form directly in 21).

The backlight assembly 40 is disposed along side surfaces of the optical members 401, 402, and 403, the light guide plate 404, the reflector plate 406, and the light guide plate 404, and emits light from the lamp 407 and the lamp 407. And a lamp reflector 408 that reflects the emitted light to the light guide plate 404.

The optical members 401, 402, and 403 are interposed between the emission surface of the light guide plate 404 and the liquid crystal display panel 20 to improve the luminance uniformity of the light generated by the lamp 407, and the emission surface of the light guide plate 404. The diffusion film 403 for diffusing the light emitted from the light source, the prism film 402 and the prism protective film 401 to improve the viewing angle by changing the path of the diffused light diffused from the diffusion film 403.

The light guide plate 404 is a light guide for guiding the light incident from the lamp 407 and outputs a surface light source to the upper part. The light guide plate 404 is a polymethyl methacrylate (PMMA) resin or a cyclic olefin polymer (COP) having excellent light transmittance. Is made of back. The light guide plate 404 is provided in a plate type, but may be a wedge type.

In order to more effectively convert the light incident from the lamp 407 toward the liquid crystal display panel 20, a prism pattern A is formed on the reflective surface of the light guide plate 404. The prism pattern A may be formed by a stamper method. The stamper method is a pattern made of a material such as silicon dioxide (SiO ₂ ) or quartz, such as electron beam lithography, FIB (focused ion beam) and RIE (reactve ion etching). To form a predetermined pattern using the produced pattern as a mold.

On the prism pattern A, a coating layer 405 containing silver having excellent reflection performance is formed. The coating layer 405 may be formed by a technique such as sputtering or vacuum deposition.

The reflective plate 406 is positioned under the light guide plate 404. The reflector 406 may be made of PET, foamed PET, or polycarbonate (PC). The reflecting plate 406 may be a flexible type or a rigid type composed of a plate.

The lamp 407 may use a Cold Cathode Fluorescent Lamp (CCFL) that is small in size and capable of high luminance. Highly efficient rare earths (Y, Ce, Tb, etc.) are mainly used as the CCFL phosphors. For liquid crystal displays, white phosphors containing R (Red), G (Green), and B (Blue) phosphors are mixed. Three wavelength types are mainly used.

The lamp reflector 408 may be made of a stainless steel sus or brass. The lamp reflector 408 diffusely reflects the light from the lamp 407 and supplies it to the light guide plate 404.

In the first embodiment, a coating layer 405 including silver is formed on the reflective surface of the light guide plate 404 to reduce light leakage. This will be described with reference to FIG. 3.

Light incident from the lamp 407 into the light guide plate 404 passes through three paths. The first path is directly reflected from the reflective surface of the light guide plate 404 and transmitted to the liquid crystal display panel 20. The second path is that light leaked from the light guide plate 404 is reflected by the reflective plate 406 and then transmitted to the liquid crystal display panel 20 again. The third path is that light leaked from the light guide plate 404 is reflected by the reflector 406, but is not injected into the light guide plate 404, but is reflected between the light guide plate 404 and the reflector 406 and disappears.

As in the first embodiment, when the coating layer 405 including silver is formed on the reflective surface of the light guide plate 404, most of the light incident on the light guide plate 404 does not leak under the light guide plate 404, but the coating layer 405 does not leak. Reflected from). Accordingly, the optical loss caused by the leakage of light in the minute gap B between the coating layer 405 and the reflector 406 is substantially reduced, thereby improving light efficiency and providing high brightness characteristics to the liquid crystal display panel 20. can do.

The reflecting plate 406, which used to increase the conventional light efficiency, serves to protect the coating layer 405, and may not be used in some cases.

A liquid crystal display according to a second embodiment of the present invention will be described with reference to FIG.

According to the second embodiment, the V-cut pattern C is formed on the reflective surface of the light guide plate 404. The V-cut pattern C may also be formed by a stamper method, and a coating layer 405 including silver is formed on the V-cut pattern C as in the first embodiment. The light provided from the lamp 407 may be reflected by the coating layer 405 of the light guide plate 404 with high efficiency to provide a high brightness characteristic to the liquid crystal display panel 20.

A liquid crystal display according to a third embodiment of the present invention will be described with reference to FIG.

According to the third embodiment, the dot pattern D is formed on the reflective surface of the light guide plate 404. The dot pattern D is formed by printing a diffusion ink having a fine dot shape on the reflective surface of the light guide plate 404. The area ratio occupied by the dot per unit area is smaller in the side closer to the lamp 407, and the area ratio occupied by the dot per unit area is larger in the side farther from the lamp 407. As a result, light loss incident on the liquid crystal display panel 20 can be reduced, and a uniform surface light source can be obtained on the light guide plate 404. At this time, the shape of the dot may have a variety of forms. As in the first embodiment, a coating layer 405 containing silver is formed on the dot pattern D. FIG. The light provided from the lamp 407 may be reflected by the coating layer 405 with high efficiency to provide high brightness characteristics to the liquid crystal display panel 20.

In the first to third embodiments according to the present invention, a polymer material may be attached to the reflective surface of the light guide plate 404 instead of the coating layer 405 containing silver. The polymeric material can be attached by a laminating method. The laminating method is a method of adhering or covering a film, unlike a coating for applying a predetermined substance to a surface. The polymer material also has good reflection performance and performs a function similar to that of the coating layer 405 containing silver. The polymer material may be made of any one of PET and PC.

Unlike the above embodiment, the light source may be an electroluminescence (EL), a light emitting diode (LED), a hot cathode fluorescent lamp (HCFL), or the like instead of the CCFL.

Although some embodiments of the invention have been shown and described, it will be apparent to those skilled in the art that the embodiments may be modified without departing from the spirit or spirit of the invention. . It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents.

As described above, according to the present invention, a liquid crystal display device excellent in light efficiency is provided.

Claims (9)

A liquid crystal display panel; A light guide plate disposed on a rear surface of the liquid crystal display panel, the light guide plate having a light emitting surface for supplying light to the liquid crystal display panel, and a reflective surface facing the light emitting surface and having a coating layer including silver; And a light source unit disposed along at least one side of the light guide plate. The method of claim 1, The coating layer is a liquid crystal display, characterized in that formed by the sputtering method. The method of claim 1, And the coating layer covers the entire reflective surface of the light guide plate. A liquid crystal display panel; A light guide plate disposed on a rear surface of the liquid crystal display panel, the light guide plate having a light emitting surface for supplying light to the liquid crystal display panel, and a reflective surface opposite to the light emitting surface and to which a polymer material is attached; And a light source unit disposed along at least one side of the light guide plate. The method of claim 4, wherein And the polymer material is attached by a laminating method. The method of claim 4, And the polymer material is attached to the entire reflective surface of the light guide plate. The method of claim 4, The polymer material is a liquid crystal display device, characterized in that the polyethylene terephthalate (PET) film. The method according to claim 1 or 4, The reflective surface of the light guide plate is patterned by any one of a prism pattern, a V-cut pattern and a dot pattern. The method according to claim 1 or 4, And a reflecting plate on the rear surface of the light guide plate.

Images