KR20050067313A - Diffusion plate for preventing inferiority and back light structure of liquid crystal display device having thereof - Google Patents

Abstract

The diffusion plate of the present invention is applied to a backlight of a liquid crystal panel, and is formed of a glass substrate and a diffusion portion for diffusing light incident on the glass substrate. Since glass is resistant to heat and moisture, deformation does not occur due to heat and moisture, and thus defects caused by deformation of the diffusion plate can be prevented. A glass film is attached to the glass diffusion plate to prevent breakage of the glass substrate due to brittleness.

Description

Diffusion plate prevented deformation and backlight structure of liquid crystal display device having the same {DIFFUSION PLATE FOR PREVENTING INFERIORITY AND BACK LIGHT STRUCTURE OF LIQUID CRYSTAL DISPLAY DEVICE HAVING THEREOF}

The present invention relates to a diffuser plate of the backlight, and more particularly, to a diffuser plate and a backlight structure having the same to prevent the deterioration of the quality by preventing the deformation caused by heat and moisture made of glass.

Recently, with the development of various portable electronic devices such as mobile phones, PDAs, and notebook computers, there is an increasing demand for flat panel display devices for light and thin applications. Such flat panel displays are being actively researched, such as LCD (Liquid Crystal Display), PDP (Plasma Display Panel), FED (Field Emission Display), VFD (Vacuum Fluorescent Display), but mass production technology, ease of driving means, Liquid crystal display devices (LCDs) are in the spotlight for reasons of implementation.

The liquid crystal display is a transmissive display and displays a desired image on the screen by adjusting the amount of light passing through the liquid crystal layer by the refractive index anisotropy of the liquid crystal molecules. Accordingly, in the liquid crystal display device, a back light, which is a light source passing through the liquid crystal layer, is provided for displaying an image. In general, the backlight can be classified into two types.

The first is a side type backlight that is provided on the side of the liquid crystal panel to provide light to the liquid crystal layer, and the second is a direct type backlight that provides light directly under the liquid crystal panel.

The side backlight may be installed on the side of the liquid crystal panel to supply light to the liquid crystal layer through the reflection plate and the light guide plate. Therefore, since the thickness can be made thin, it is mainly used in notebooks and the like which require a thin display device. However, the side backlight is difficult to apply to a large area liquid crystal panel because the lamp for emitting light is located on the side of the liquid crystal panel, it is difficult to obtain high brightness because light is supplied through the light guide plate. Therefore, there has been a problem that it is not suitable for the large-area liquid crystal panel for LCD TVs, which has been in the spotlight recently.

The direct type backlight is used to manufacture a liquid crystal panel for an LCD TV since the light emitted from the lamp is directly supplied to the liquid crystal layer and can be applied to a large area liquid crystal panel as well as high brightness.

 1 shows a structure of a conventional liquid crystal display device in which a direct type backlight is applied.

As shown in the figure, the liquid crystal display device 1 is largely comprised of a liquid crystal panel 3 and a backlight 10 provided on the rear surface of the liquid crystal panel 3. The liquid crystal panel 3 is where an actual image is realized, and is composed of a transparent lower substrate 3a such as glass and an upper substrate 3b and a liquid crystal layer (not shown) formed therebetween. In particular, although not shown in the drawing, the lower substrate 3a is a TFT substrate on which a driving element such as a thin film transistor and a pixel electrode are formed, and the upper substrate 3b is formed of a color filter layer. It is a color filter substrate. In addition, a driving circuit unit 5 is provided on the side of the lower substrate 3a to apply signals to the thin film transistor and the pixel electrode formed on the lower substrate 3a, respectively.

The backlight 10 includes a plurality of lamps 11 that emit light and supply light to the liquid crystal panel 3, and a reflector 17 that reflects light emitted from the lamp 11 to improve light efficiency. And a diffuser plate 15 provided above the lamp 11 to diffuse the light generated from the lamp 11.

Although not shown in the drawing, various optical films such as diffusion sheets are provided on the diffusion plate 15. The diffusion plate 15 and the diffusion sheet diffuse light generated from the lamp 11 so that uniform light is incident on the entire liquid crystal panel 3.

In general, the diffusion plate 15 is made of acrylic resin having good diffusion characteristics such as poly-methyl-methacryl acrylate (PMMA). However, the diffusion plate 15 using the acrylic resin has the following problems.

First, the diffusion plate 15 is sag downward by gravity. In general, since the diffuser plate 15 made of acrylic resin is flexible, when applied to a large-area LCD TV that is in the spotlight in recent years, the diffuser plate 15 causes the central region to fall downward due to gravity. This deflection of the diffuser plate 15 makes the spacing between the diffuser plate 15 and the lamp 11 uneven and the spacing between the diffuser plate 15 and the liquid crystal panel 3 uneven to the liquid crystal panel 3. Allow light to enter.

Second, heat deformation occurs. Since PMMA is weak in heat, deformation is caused by heat generated from the lamp 11, the drive element, or the like. This deformation forms wrinkles in the diffusion plate 15, making it impossible to supply uniform light to the liquid crystal panel 3.

Third, deformation by moisture occurs. When moisture penetrates from the outside, the PMMA is deformed and non-uniform light is supplied to the liquid crystal panel 3.

As described above, the deflection due to gravity, the deformation due to heat or moisture, is the main cause of deterioration of the image quality of the liquid crystal display device, such as uneven light incident on the liquid crystal panel 3 and irregular spots on the screen.

The present invention has been made in view of the above, and an object of the present invention is to provide a diffuser plate which is formed of a glass material resistant to heat and moisture, thereby preventing the occurrence of defects due to heat and moisture.

Another object of the present invention is to provide a diffuser plate which can reduce the thickness by preventing the bending by gravity by using a glass material having a strong strength.

Still another object of the present invention is to provide a backlight structure of the liquid crystal display device having the diffusion plate.

In order to achieve the above object, the backlight structure according to the present invention is formed on at least one lamp for supplying light to the liquid crystal panel, a glass substrate and at least one surface of the glass substrate to diffuse the light generated from the lamp liquid crystal panel It consists of a diffuser plate consisting of a diffuser to enter.

The diffusion part is a scratch formed on the glass substrate, a polycarbonate or polymer pattern attached to the glass substrate, and a reinforcing film is attached to at least one surface of the diffusion plate to prevent breakage of the diffusion plate. In addition, a part of the diffusion plate is inserted into and supported by a supporting member installed on the case.

In the present invention, since the strength is good, it does not sag downward due to gravity, and the diffusion plate of the liquid crystal display device is manufactured using a material resistant to heat and moisture. In particular, in the present invention, diffusion is produced using glass. Since the glass not only satisfies the above characteristics but also has good transmittance, it may be usefully used as a diffusion plate of a liquid crystal display device.

In order to improve the diffusion property, the glass is processed on its surface or a diffusion material is attached. The glass diffusion plate is attached to the glass diffusion plate can be prevented from being damaged by the external force. In addition, the glass diffusion plate is fixed by the support member is prevented from being damaged by an external impact.

The use of the glass diffuser plate reduces the overall thickness of the backlight. Conventional diffuser plate made of PMMA has a relatively thick thickness of the diffuser plate 2 to 3mm to prevent the diffusion plate from sagging downward due to gravity, but the glass diffusion plate does not cause the sag caused by gravity It is possible to produce a thinner than the conventional diffusion plate. Therefore, it is possible to reduce the thickness of the glass diffusion plate, and eventually reduce the thickness of the backlight on which the diffusion plate is installed. Such a decrease in the thickness of the backlight reduces the thickness of the liquid crystal display device, thereby making it possible to manufacture a thinner display device.

Hereinafter, with reference to the accompanying drawings will be described in detail with respect to the diffusion plate according to the present invention.

2 is a view showing a diffuser plate 115 of a backlight according to the present invention. As shown in FIG. 2, the diffusion plate 115 includes a glass substrate 130 and a diffusion unit 140 formed on the glass substrate 130. Since glass does not deteriorate even after exposure to visible or ultraviolet light for a long time, there is an advantage that the glass has a long life compared to the conventional PMMA diffusion plate. In addition, since glass is resistant to moisture and heat, deformation due to moisture or heat does not occur. In addition, since the glass substrate 130 has a large strength, the glass substrate 130 may be thinner than a conventional PMAA diffusion plate and may be formed to about 1 mm or less.

When light is incident on the diffuser plate 115, the incident light is scattered and diffused by the diffuser 140 of the diffuser plate 115. Since the diffusion plate 115 is employed in the backlight of the liquid crystal display device, the light generated from the backlight is diffused by the diffusion plate 115 and then uniformly enters the liquid crystal panel.

3A to 3C are enlarged views of portion A of FIG. 2, showing the structure of diffusion parts 140 of different examples. At this time, each drawing shows various examples of the diffusion unit according to the present invention.

First, as shown in FIG. 3A, the diffusion part 140 is formed of a scratch 141 formed on the glass substrate 130. The scratch 141 is formed by strongly projecting sand or the like onto the glass substrate 130, and is mainly formed in a triangular shape having various sizes as shown in the drawing. Light incident on the diffuser plate 115 is scattered irregularly by the triangular scratches 141 to cause light diffusion.

In addition, as shown in FIG. 3B, the diffusion part 140 may be made of a synthetic resin such as a sphere-shaped polycarbonate 142 attached to the glass substrate 130. The polycarbonate is attached to the glass substrate 130 by the photocuring agent 143. Since the polycarbonate 142 can arbitrarily adjust its size and density to be adhered to it, it is possible to control the degree of light diffusion as necessary.

In addition, the diffusion unit 140 may be formed of a photopolymer pattern 145, as shown in FIG. 3C. At this time, the photopolymer pattern 145 is formed by a photo process using a mask after stacking the photopolymer, a rectangular photopolymer pattern by applying heat to the patterned photopolymer to make a curved shape for diffusing light 145 is curved to enable irregular scattering (ie diffusion).

As described above, in the present invention, the scratch 141 is formed on the glass substrate 130 or the polycarbonate 142 or the photopolymer pattern 145 is formed to form the diffuser 140 for scattering light. In this case, although the diffusion portion 140 is formed only on the upper portion of the glass substrate 130, the diffusion portion 140 may be formed on the lower portion of the glass substrate 130 or may be formed on both the upper portion and the lower portion. It may be.

On the other hand, since the glass substrate 130 has brittleness compared to acrylic resins such as PMMA, the glass substrate 130 is easily broken by an external small impact. Therefore, in the present invention, as shown in FIG. 4, the reinforcement film 149 is attached to the diffusion part 140 formed on the glass diffusion plate 115 to prevent the glass substrate 130 from being damaged. In this case, the reinforcement films 149a and 149b may be attached only to one surface of the diffusion plate 115, but may be attached to both surfaces as shown in the drawing.

In addition, in the drawings, the reinforcement films 149a and 149b may be attached to the outer side of the diffusion part 140, but may be formed directly on the inner side of the diffusion part 140, that is, on the glass substrate 130.

By reinforcing the reinforcement films 149a and 149b as described above, it is possible to prevent the disadvantages of the glass diffusion plate 115, that is, cracking due to brittleness.

5 is an exploded perspective view illustrating a structure of a backlight in which the diffusion plate 115 having the above structure is actually mounted. At this time, the detailed structure of the diffusion plate 115 is not shown for convenience of description, but the diffusion plate 115 is a structure of the diffusion plate 115 and the structure shown in FIG. Will comprise a diffuser plate 115.

As shown in FIG. 5, a plurality of lamps 111 for supplying light to the liquid crystal panel (not shown) are installed in the case 123, and the lower part of the lamp 111, that is, the case 123. The reflecting plate 117 is provided on the bottom surface of the lamp 111 to reflect light incident from the lamp 111 to improve the light efficiency of the lamp 111.

Although not shown in the figure, the case 123 may be provided with a lamp fixing means for fixing the lamp 111.

The diffusion plate 115 is mounted to the case 123 (or lamp fixing means). At this time, both ends of the diffusion plate 115 are inserted into the support member 125. Although not shown in the drawings (the coupling relationship is not shown since it is an exploded perspective view), since the support member 125 is attached to the case 123 (or lamp fixing means), the diffusion plate is attached to the support member 125. Both end surfaces of 115 are inserted so that the diffusion plate 115 is firmly fixed to the case 123 (or lamp processing means). Therefore, since the diffusion plate 115 is not moved by an external impact, the damage of the diffusion plate 115 can be prevented.

On the other hand, the end of the glass diffusion plate 115 is easily broken, but since the end is inserted into the support member 125 in a predetermined area as described above, it is possible to effectively prevent the end of the diffusion plate 115 from being broken. do. Furthermore, since the support member 125 is made of a buffer material that absorbs external shocks, it is possible to more effectively prevent damage due to impacts.

As described above, in the present invention, by using the glass diffusion plate, it becomes possible to prevent deformation due to heat and moisture or sag due to gravity. In addition, since the glass diffusion plate can be formed thin, it can be effectively applied to the backlight of the thin liquid crystal display device. The glass diffusion plate is not used alone, but is mounted on the backlight together with the diffusion film or the prism film to improve the performance of the backlight.

Meanwhile, the present invention may be applied to all types of backlights. In the above description, the present invention is mainly applied to the direct type backlight, but this is only one example for explaining the present invention and does not limit the present invention. Practically, the diffusion plate of the present invention may be applied not only to the direct type backlight but also to the side type backlight, and may be applied to all kinds of backlights currently available and backlights of various structures to be manufactured in the future. In this case, various well-known configurations according to various types of backlights may be added. For example, in the case of the side type backlight, a light guide plate for guiding light to the liquid crystal panel may be provided.

As described above, in the present invention, since the diffusion plate is made of glass, the following effects can be obtained.

First, it is possible to prevent the deflection in the downward direction by gravity. Since glass has a high strength, the phenomenon that the glass sags downward does not occur even when a large area liquid crystal display device is manufactured.

Second, deformation by heat and moisture does not occur. Since glass is highly resistant to heat and moisture, deformation due to moisture and heat does not occur, and thus, it is possible to prevent deterioration of image quality of the liquid crystal display device due to such deformation.

Third, a thin backlight is enabled. Since glass has a high strength, deformation due to gravity does not occur even when a diffusion plate is made relatively thin. Therefore, the glass diffusion plate is reduced in thickness compared to the conventional PMMA diffusion plate, and eventually the thickness of the backlight on which the glass diffusion plate is mounted is also reduced.

1 is a view showing the structure of a general liquid crystal display device.

2 is a view showing the structure of a diffusion plate according to the present invention.

3A to 3C are enlarged views of a portion A of FIG. 2.

4 is a view showing a diffusion plate of the present invention provided with a reinforcing film.

5 is a view showing a structure of a backlight having a diffusion plate according to the present invention.

*** Explanation of symbols for main parts of drawing ***

115: diffuser 123: case

125: support member 130: glass substrate

140: diffusion portion 141: scratch

142 polocarbonate 145 polymer pattern

Claims (11)

At least one lamp supplying light to the liquid crystal panel; And A backlight structure comprising a glass substrate and a diffusion plate formed on at least one surface of the glass substrate to diffuse light generated from a lamp to be incident on the liquid crystal panel. The backlight structure of claim 1, wherein the diffusion part is a scratch formed on a glass substrate. The backlight structure of claim 1, wherein the diffusion part comprises a polycarbonate attached to the glass substrate. 4. The backlight structure according to claim 3, wherein the polycarbonate is spherical. The backlight structure of claim 1, wherein the diffusion part is a polymer pattern. The backlight structure of claim 1, further comprising at least one diffusion sheet disposed on the diffusion plate to diffuse the light diffused by the diffusion plate again. The backlight structure of claim 1, further comprising a reinforcing film attached to at least one surface of the diffusion plate. The method of claim 1, A case in which the lamp and the diffusion plate are installed; And a reflector provided on the bottom surface of the case to reflect light generated from the lamp to the liquid crystal panel. The backlight structure according to claim 8, further comprising a support member installed in the case and supporting at least one end of the diffusion plate. 10. The backlight structure of claim 9, wherein the support member is made of a cushioning material to absorb shocks. Glass substrates; And And a diffusion plate formed on at least one surface of the glass substrate to diffuse the incident light.