KR20060021142A - Display apparatus - Google Patents

Abstract

A display device that can improve display quality is disclosed. A backlight assembly is provided below the display panel for displaying an image, and the backlight assembly includes a lamp for generating light and a light collecting sheet for collecting light to provide light to the display panel. The first polarizer is attached to the lower surface of the display panel to polarize light incident on the display panel. The surface cured layer is coated on the lower surface of the first polarizing plate to protect the light collecting sheet and the first polarizing plate, and diffuses the light output from the backlight assembly to prevent moiré and sheetum. Therefore, the display quality of the display device can be improved.

Description

Display device {DISPLAY APPARATUS}

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

FIG. 2 is a cross-sectional view of the liquid crystal display shown in FIG. 1 taken along the line II ′. FIG.

3 is an enlarged view illustrating an enlarged view of the first polarizing plate and the surface hardened layer illustrated in FIG. 2.

4 is a cross-sectional view illustrating a lower surface treatment structure of a first polarizing plate according to another exemplary embodiment of the present invention.

* Description of the symbols for the main parts of the drawings *

100: liquid crystal display panel 110: first display substrate

120: second display substrate 130: liquid crystal layer

210: first polarizing plate 220: second polarizing plate

230: surface hardened layer 240: antistatic film

300: backlight assembly 310: lamp unit

320: light guide plate 330: diffusion sheet

360: light collecting sheet 370: reflector

The present invention relates to a display device, and more particularly, to a display device capable of improving display quality.

In general, the liquid crystal display includes a liquid crystal display panel for displaying an image and a backlight assembly provided under the liquid crystal display panel to provide light to the liquid crystal display panel. The liquid crystal display panel includes a lower substrate, an upper substrate facing the lower substrate, and a liquid crystal layer interposed between the lower substrate and the upper substrate. The lower polarizer is attached to the lower surface of the lower substrate, and the upper polarizer is attached to the upper surface of the upper substrate.

Meanwhile, the backlight assembly includes a lamp for generating light and a light guide plate for guiding the light toward the liquid crystal display panel. The backlight assembly further includes a diffusion sheet provided on the light guide plate to improve the brightness of light emitted from the light guide plate, and a two prism sheet provided on the diffusion sheet to collect the diffused light.

In the two prism sheets, horizontal prism patterns parallel to the horizontal direction of the liquid crystal display panel and vertical prism patterns parallel to the vertical direction are formed, respectively. At this time, the moiré phenomenon occurs on the screen of the display device because the horizontal prism pattern and the vertical prism pattern cross each other.

In order to prevent such moiré, the conventional backlight assembly further includes a protective sheet on two prism sheets. The protective sheet is composed of a PET (Polyethyleneterephehalate) film and a plurality of polymer beads contained in the PET film. Therefore, the protective sheet protects the prism patterns formed on the two prism sheets, and diffuses the light output from the prism sheet to suppress the moiré phenomenon. However, PET, which is a main material of the protective sheet, is a weak material for heat, so that the protective sheet is swept by the heat, and as a result, a stain occurs on the screen of the display device, thereby degrading display quality.

In addition, an antiglare layer is coated on the lower surface of the lower polarizer. The anti-glare layer diffuses light incident from the backlight assembly to expand the viewing angle of the liquid crystal display. However, the overall brightness of the liquid crystal display device is lowered by the protective sheet and the anti-glare layer.

Accordingly, it is an object of the present invention to provide a display device for improving display quality.

A display device according to an aspect of the present invention includes a display panel, a backlight assembly, a first polarizing plate, and a surface hardening layer.

The display panel displays an image using light, and the backlight assembly includes a lamp for generating the light and a light collecting sheet for collecting the light, thereby providing the light to the display panel.

The first polarizer is attached to a lower surface of the display panel to polarize the light incident on the display panel. The surface curing layer is coated on the lower surface of the first polarizing plate to protect the light collecting sheet and the first polarizing plate, and diffuse the light output from the backlight assembly.

According to such a display device, the surface hardening layer is coated on the lower surface of the first polarizing plate, thereby preventing moiré phenomena caused by the light condensing sheet, and the protective sheet for protecting the light condensing sheet is omitted, whereby Removed. In addition, the display quality of the display device can be improved by adding diffusion particles for improving the viewing angle to the surface hardened layer.

Hereinafter, with reference to the accompanying drawings, it will be described in detail a preferred embodiment of the present invention.

1 is a perspective view of a liquid crystal display according to an exemplary embodiment of the present invention, and FIG. 2 is a cross-sectional view of the liquid crystal display shown in FIG. 1 taken along the cutting line I ′.

1 and 2, the liquid crystal display device 400 according to an exemplary embodiment of the present invention may include a liquid crystal display panel 100, a first polarizing plate 210, a second polarizing plate 220, and a surface hardening layer 230. ) And backlight assembly 300.

The liquid crystal display panel 100 includes a first display substrate 110, a second display substrate 120 facing the first display substrate 110, and a first display substrate 110 and a second display substrate ( And a liquid crystal display panel 100 including an LCD layer interposed therebetween to display an image.

Although not shown in the drawing, the first display substrate 110 is a substrate in which thin film transistors and pixel electrodes are arranged in a matrix form, and the second display substrate 120 is a substrate having a common electrode facing the pixel electrode. to be. The second display substrate 120 is further provided with a color filter layer made of color pixels that are expressed in a predetermined color by light.

On the other hand, the liquid crystal layer 130 is composed of a plurality of liquid crystal, the liquid crystal used in the liquid crystal display device 400 according to an embodiment of the present invention is a twisted nematic liquid crystal. Therefore, the liquid crystals are arranged by the electric field difference applied to the pixel electrode and the common electrode.

The first polarizer 210 is attached to the lower surface of the first display substrate 110 to polarize the light incident on the liquid crystal display panel 100, and the second polarizer 220 is the second display substrate. Attached to the upper surface of the 120 to polarize the light emitted from the liquid crystal display panel 100.

The surface hardening layer 230 is coated on the lower surface of the first polarizing plate 210. The surface cured layer 230 includes a cured resin and a hydrophilic material contained in the cured resin. The curable resin is composed of an ultraviolet curable resin, for example, alkylol acrylate or urethane acrylate, and the hydrophilic material is, for example, n-polyvinylpyrrolidone.

As the thickness of the surface hardened layer 230 increases, the hardness of the surface hardened layer 230 increases. However, as the difference between the hardness of the surface hardened layer 230 and the hardness of the first polarizing plate 210 increases, a difference in shrinkage occurs and the surface hardened layer 230 is cracked or cracked. Therefore, the surface hardened layer 230 preferably has a thickness of 3 ~ 8㎛.

Here, the hydrophilic material prevents the surface hardening layer 230 from being cracked or cracked due to the difference in hardness between the first polarizing plate 210 and the surface hardening layer 230.

As such, the surface hardening layer 230 may be coated on the lower surface of the first polarizing plate 210 to prevent moiré phenomenon caused by the light collecting sheet 360 (shown in FIG. 1). In addition, the surface hardening layer 230 is made of a material resistant to heat, thereby eliminating the conventional situm phenomenon.

In addition, the surface hardening layer 230 may protect the first polarizing plate 210 from being damaged by friction between the backlight assembly 300 and the first polarizing plate 210.

The surface hardened layer 230 will be described in more detail later with reference to FIG. 3.

The backlight assembly 300 includes a lamp unit 310, a light guide plate 320, a diffusion sheet 330, a light collecting sheet 360, and a reflecting plate 370. The lamp unit 310 includes a lamp 311 generating the light and a lamp cover 312 covering the lamp 311 and reflecting the light in the direction of the light guide plate 320.

The light guide plate 320 has a rectangular plate shape to guide the light provided from the lamp unit 310 toward the display panel 100. The lamp unit 310 is disposed adjacent to one side 321 of a plurality of side surfaces of the light guide plate 320 to receive the light. Light incident on the light guide plate 320 through the side surface 321 is reflected by the bottom surface 322 of the light guide plate 320 and then exits to the top surface 323 of the light guide plate 320.

In order to improve luminance uniformity of the light emitted from the light guide plate 320, the lower surface 322 of the light guide plate 320 is inclined closer to the upper surface 323 as the distance from the lamp 310 is increased. Therefore, the luminance uniformity may be improved by preventing the luminance of the light emitted from the light guide plate 320 from decreasing as the distance from the lamp 310 increases.

The diffusion sheet 330 is disposed on the upper surface 323 of the light guide plate 320 to diffuse light emitted from the upper surface 323, and the light collecting sheet 360 is disposed on the diffusion sheet 330. It is provided to collect the light diffused by the diffusion sheet 330.

The light condensing sheet 360 may have a plurality of first prism patterns 341 extending in a first direction D1 to be different from the first prism sheet 340 and the first direction D1 to condense the light. A plurality of second prism patterns 351 extending in the second direction D2 are formed to form the second prism sheet 350 that collects the light. The plurality of first prism patterns 341 are orthogonal to each other and the plurality of second prism patterns 351.

The reflective plate 370 is provided under the light guide plate 320 to reflect the light leaked from the lower surface 322 of the light guide plate 320 toward the light guide plate 320. Thus, the reflector plate 370 improves the light efficiency of the backlight assembly 300.

3 is an enlarged view illustrating an enlarged view of the first polarizing plate and the surface hardened layer illustrated in FIG. 2.

Referring to FIG. 3, a surface hardening layer 230 is coated on the lower surface of the first polarizing plate 210. The surface cured layer 230 is made of a curable resin and a hydrophilic material contained in the curable resin. Here, the surface hardened layer 230 has a thickness (t) of 3 ~ 10㎛.

In addition, the surface hardening layer 230 contains diffusion particles 231 for diffusing the light emitted from the backlight assembly 300 (shown in FIG. 1). The diffusion particles 231 are made of acrylic beads having a refractive index similar to that of the cured resin. If the diameter d of the diffusion particles 231 is large, the light efficiency is decreased. However, if the diameter d is small, the effect of suppressing moiré phenomenon is reduced. Therefore, the diffusion particles 231 preferably have a diameter (d) of 5 ~ 10㎛.

The surface hardened layer 230 contains the diffusion particles 231 having a diameter d larger than the thickness t of the surface hardened layer 230. The diffusion particles 231 having a diameter d larger than the thickness t of the surface hardened layer 230 improves the hardness of the surface hardened layer 230. In addition, the haze value of the surface hardened layer 230 is appropriately 40 to 60% level that can suppress the moiré phenomenon while preventing the light efficiency decrease. The haze value is determined by the number and size of the diffusion particles 231. Therefore, the number and size of the diffusion particles 231 may be adjusted to maintain a haze value of about 40 to 60%.

As such, the surface hardening layer 230 may be coated on the lower surface of the first polarizing plate 210 to prevent moiré phenomenon caused by the light collecting sheet 360 (shown in FIG. 1). In addition, the surface hardening layer 230 is made of a material resistant to heat, thereby eliminating the conventional situm phenomenon.

In addition, by adding the diffusion particles 231 to the surface hardening layer 230 to increase the haze value of the surface hardening layer 230, it is possible to diffuse the light collected by the light collecting sheet 360, As a result, the viewing angle of the liquid crystal display device 400 may be improved as a whole.

4 is a cross-sectional view illustrating a lower surface treatment structure of a first polarizing plate according to another exemplary embodiment of the present invention.

Referring to FIG. 4, in the display device according to another exemplary embodiment, an antistatic layer 240 is further provided between the first polarizing plate 210 and the surface hardening layer 230. The antistatic layer 240 includes an organic material and a metal powder contained in the organic material. In one embodiment of the present invention, the metal powder is made of indium tin oxide (ITO).

Accordingly, the antistatic layer 240 suppresses static electricity generated by friction between the first polarizing plate 210 and the backlight assembly 300 (shown in FIG. 1). As a result, it is possible to prevent the display quality of the display device from being degraded due to staining caused by static electricity.

Although not shown in the drawing, the antistatic layer 240 may be provided in the first polarizing plate 210. The first polarizing plate 210 includes a polarizing layer and first and second protective layers attached to upper and lower portions of the polarizing layer, respectively. The first and second protective layers are attached to the polarizing layer by an adhesive. At this time, the metal powder is contained in the adhesive to form an antistatic layer.

According to such a display device, the surface hardened layer is coated on the lower surface of the first polarizing plate, thereby preventing moiré phenomenon by the light condensing sheet, and the protective sheet for protecting the light condensing sheet is omitted. Is removed. As a result, the display quality of the display device is improved.

In addition, by adding the diffusion particles for improving the viewing angle to the surface hardened layer, it is possible to omit the anti-glare layer previously coated on the first polarizing plate. Therefore, the luminance decrease by the anti-glare layer can be prevented and the overall luminance of the display device can be improved.

Although described with reference to the embodiments above, those skilled in the art will understand that the present invention can be variously modified and changed without departing from the spirit and scope of the invention as set forth in the claims below. Could be.

Claims (11)

A display panel displaying an image using light; A backlight assembly comprising the lamp for generating the light and the light collecting sheet for collecting the light, the backlight assembly providing the light to the display panel; A first polarizer attached to a lower surface of the display panel to polarize the light incident on the display panel; And And a surface hardening layer coated on a lower surface of the first polarizing plate to protect the light collecting sheet and the first polarizing plate and to diffuse the light output from the backlight assembly. The display device of claim 1, wherein the surface hardened layer has a thickness of about 3 μm to about 8 μm. The display device of claim 1, wherein the surface curing layer comprises a cured resin and a hydrophilic material contained in the cured resin. The display device of claim 3, wherein the cured resin comprises an alkylol acrylate or a urethane acrylate. The display device of claim 3, wherein the hydrophilic material comprises n-polyvinylpyrrolidone. The display device of claim 1, wherein the surface hardened layer contains diffused particles for diffusing the light. According to claim 6, The diameter of the diffusion particles is 5 ~ 10㎛, And a haze value of the surface hardened layer is 40 to 60%. The display device of claim 6, wherein the diffusion particles are made of acrylic beads. The display device of claim 1, further comprising an antistatic layer disposed between the first polarizing plate and the surface hardening layer to prevent damage of the first polarizing plate by static electricity. The display device of claim 1, further comprising a second polarizing plate attached to an upper surface of the display panel to polarize light emitted from the display panel. The display device of claim 1, wherein the light collecting sheet comprises first and second prism sheets each having first and second prism patterns extending in different directions.

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