KR20030087800A - Liquid crystal display apparatus - Google Patents

Abstract

PURPOSE: A liquid crystal display is provided to improve display quality of the liquid crystal display and to increase luminance of the liquid crystal display. CONSTITUTION: A liquid crystal display includes a light source(330) for generating the first light beam, a light diffuser(320), a light path converter(360), and a liquid crystal display panel(500). The light diffuser receives the first light beam through the first face and diffuses the first light beam to output the diffused light beam as the second light beam having a uniform luminance distribution. The light path converter has a protrusion formed at a region of the first face where the quantity of the first light beam incident thereon is relatively high, and a depression formed at a region of the first face where the quantity of the first light beam incident thereon is relatively small. The light path converter changes the path of the first light beam. The liquid crystal display panel receives the second light beam and controls transmissivity of the second light beam to display images.

Description

Liquid crystal display device {LIQUID CRYSTAL DISPLAY APPARATUS}

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

Recently, along with the development of the technology of the information processing apparatus, the development of the technology of the display apparatus for interfacing so that a user can recognize the data processed by the information processing apparatus has been made.

As a display device, a liquid crystal display device having a light weight, a small size, and a function such as full-color and high resolution is widely used. The liquid crystal display device is a display device for converting a change in optical properties of the liquid crystal cell into a visual change. Since the liquid crystal display does not emit light by itself, light is supplied from a backlight assembly attached to a rear surface of the liquid crystal display panel to display an image.

The backlight assembly is divided into a direct type and an edge type according to the position of the light source. The direct type is a method of directly dimming the front surface of the panel by placing a light source under the liquid crystal display panel, and compared to the edge type, a plurality of light sources can be used to secure high luminance.

1 is a cross-sectional view showing the structure of a conventional direct backlight assembly.

Referring to FIG. 1, the direct backlight assembly 100 is One or more lamps 130 for generating a first light, a reflector 140 for reflecting the first light, and a diffuser plate 120 for diffusing the first light to emit a second light having a uniform luminance distribution. ) And the diffusion sheet 110. The one or more lamps 130, the reflecting plate 140, the diffusion plate 120, and the diffusion sheet 110 are accommodated in the mold frame 150.

The mold frame 150 is formed in a box shape of a rectangular parallelepiped having an upper surface opened. An accommodation space having a predetermined depth is formed inside the mold frame 150, and a step 151 for sequentially receiving the diffusion plate 120 and the diffusion sheet 110 is sequentially formed at an upper end of the side wall constituting the accommodation space. Is formed. The reflective plate 140 is installed along the inner surface of the storage space of the mold frame 150, and the one or more lamps 130 are installed on the reflective plate 140.

In this case, a part of the first light is directly incident to the diffuser plate 120, and a part of the first light is reflected toward the diffuser plate 120 through the reflector plate 140. The first light is emitted to the second light having a wide range of angles by the diffusion plate 120. On the other hand, the diffusion sheet 110 makes the brightness of the second light uniform.

However, the direct backlight assembly 100 shown in FIG. 1 has a non-uniform luminance distribution, as seen in the first luminance distribution curve 160. That is, the region A of the diffuser plate 120 corresponding to the light emitting region of the at least one lamp 130 has a higher luminance distribution than the region B of the diffuser plate 120 corresponding to the region between the lamp and the lamp. .

In order to solve this problem, a conventional direct backlight assembly as shown in FIG. 2 has been proposed.

FIG. 2 is a cross-sectional view illustrating a structure in which a printing pattern is formed on a diffuser plate of the direct backlight assembly shown in FIG. 1.

Referring to FIG. 2, the direct type backlight assembly 100 is formed on the rear surface 121 of the diffusion plate 120 to scatter the first light incident from the one or more lamps 130. 125). The print pattern 125 is formed relatively densely in the area A and relatively sparse in the area B.

Here, the print pattern 125 controls the luminance by blocking the first light. That is, the print pattern 125 blocks a lot of light incident to the area A, thereby greatly reducing the amount of the second light emitted through the diffuser plate 120 and entering the area B. Relatively little to reduce the amount of light of the second light. As a result, the difference in the amount of light emitted from the area A and the area B is minimized.

This structure makes the luminance between the area A and the area B of the direct backlight assembly 100 uniform throughout, as can be seen in the second luminance distribution curve 162 shown in FIG. 2.

However, the print pattern 125 is easily discolored by ultraviolet rays or heat generated by the one or more lamps 130 after a predetermined time elapses. The discolored pattern is displayed on the screen of the direct type liquid crystal display, thereby degrading display quality.

In addition, the printed pattern 125 is excellent for securing the uniformity of brightness of the direct type liquid crystal display, but the direct type liquid crystal because it blocks the first light from the at least one lamp 130. Reduce the overall brightness of the display device.

SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid crystal display device capable of improving display quality.

1 is a cross-sectional view showing the structure of a conventional direct backlight assembly.

FIG. 2 is a cross-sectional view illustrating a structure in which a printing pattern is formed on a rear surface of the diffusion plate illustrated in FIG. 1.

3 is an exploded perspective view illustrating in detail a direct type liquid crystal display according to an exemplary embodiment of the present invention.

4 is a cross-sectional view illustrating in detail the direct type backlight assembly shown in FIG. 3.

5A and 5B are cross-sectional views illustrating a manufacturing process of forming an optical path changing layer on a rear surface of the diffusion plate illustrated in FIG. 4.

FIG. 6 is a cross-sectional view illustrating a structure in which a scattering agent is formed in the light path changing layer illustrated in FIG. 4.

<Description of the symbols for the main parts of the drawings>

300: direct type backlight assembly 310: diffusion sheet

320: diffuser plate 330: lamp

340: reflector 350: mold frame

360: light path changing layer 500: liquid crystal display panel assembly

700: direct type liquid crystal display device

The liquid crystal display according to the present invention for achieving the above object is provided with the first light through a light source for generating a first light, a first surface, and diffuses the first light to achieve a uniform luminance distribution as a whole. A light diffusing member which emits light having a second light, a protruding region stacked at a relatively high height on a region where the incident amount of the first light is relatively high among the first surfaces, and an incident amount of the first light among the first surfaces And a concave region stacked at a relatively low height on a low region to provide an optical path changing member for changing the path of the first light and the second light to control the transmittance of the second light to display an image. It includes a liquid crystal display panel for.

According to the liquid crystal display device described above, an optical path changing member for changing the path of the first light is stacked on the incident surface of the diffuser plate on which the first light from the light source is incident. At this time, the light path members are stacked relatively thick in the region corresponding to the light source, and relatively thin in other regions. Accordingly, the display characteristics of the liquid crystal display device can be improved by providing the liquid crystal display panel with the second light emitted from the diffuser plate with a uniform luminance distribution.

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

3 is an exploded perspective view illustrating a direct type liquid crystal display according to an exemplary embodiment of the present invention, and FIG. 4 is a cross-sectional view illustrating the direct type backlight assembly illustrated in FIG. 3 in detail.

Referring to FIG. 3, the direct type liquid crystal display device 700 includes a liquid crystal display panel assembly 500 for displaying an image and a direct type backlight assembly 300 for supplying light to the liquid crystal display panel assembly 500. Is made of.

The liquid crystal display panel assembly 500 may include a liquid crystal display panel 510, a data printed circuit board 520, a gate printed circuit board 540, a data tape carrier package (TCP) 530, and a gate. TCP 550 is included.

The liquid crystal display panel 510 is disposed between the TFT substrate 511 and the color filter substrate 513 positioned on the TFT substrate 511 and between the TFT substrate 511 and the color filter substrate 513. It consists of the liquid crystal injected (not shown). TFTs (not shown), which perform a switching role, are formed in the TFT substrate 511, a gate line is connected to a gate electrode of each TFT, a data line is connected to a source electrode, and a pixel is connected to a drain electrode. An electrode is formed.

The data line and the gate line are electrically connected to the data printed circuit board 520 and the gate printed circuit board 540 through the data TCP 530 and the gate TCP 550. Therefore, when the data and gate printed circuit boards 520 and 540 receive an electrical signal from the outside, the data and gate printed circuit boards 520 and 540 drive and drive the liquid crystal display panel assembly 500. The driving signal and the timing signal for controlling the signal are transmitted to the gate line and the data line through the data TCP 530 and the gate TCP 550.

On the other hand, the color filter substrate 513 is formed with an RGB pixel which is a color pixel for displaying an image. Therefore, the light transmitted through the liquid crystal is expressed in a predetermined color through the RGB pixel. In addition, a common electrode is formed on the front surface of the color filter substrate 513. Therefore, when a voltage is applied to the liquid crystal display panel 510, an electric field is formed between the common electrode and the pixel electrode to change the arrangement of liquid crystals therebetween.

As shown in Figures 3 and 4, the direct backlight assembly 300 is One or more lamps 330 for generating a first light, a reflector 340 for reflecting the first light, and a diffuser plate 320 for diffusing the first light to emit a second light having a uniform luminance distribution. ) And a diffusion sheet 310. The one or more lamps 330, the reflecting plate 340, the diffusion plate 320, and the diffusion sheet 310 are accommodated in the mold frame 350.

The mold frame 350 is formed in a box shape of a rectangular parallelepiped having an upper surface opened. A storage space having a predetermined depth is formed in the mold frame 350, and a first step 351 in which the diffusion plate 320 and the diffusion sheet 310 are sequentially seated on an upper end portion of the side wall constituting the storage space. Is formed. The mold frame 350 for accommodating the one or more lamps 330, the reflecting plate 340, the diffusing plate 320, and the diffusing sheet 310 is presented as an embodiment of the present invention, and the mold as well as other forms. The frame of can also be applied.

The reflective plate 340 is installed along the inner surface of the storage space of the mold frame 350, and the one or more lamps 330 are installed on the reflective plate 340. In this case, opposite ends of the one or more lamps 330 are coupled to the lamp holders 331, respectively, such that the one or more lamps 330 are stably fixed to the upper portion of the reflective plate 340.

The one or more lamps 330 have an effective light emitting area (W) and an invalid light emitting area (D). The effective light emitting area W is a region where light is generated substantially, and represents a central portion of the one or more lamps 330, and the non-effective light emitting area D is combined with the lamp holder 331. Both ends of 330 are shown, and substantially no light is generated in this area.

As shown in FIG. 4, the diffusion plate 320 and the diffusion sheet 310 are sequentially received in the first step 351. In this case, the one or more lamps 330 and the diffusion plate 320 are spaced at a predetermined interval, and the separation space is a light guide region in which the first light is guided to the diffusion plate 320. A portion of the first light is directly incident on the diffuser plate 320, and a portion of the first light is reflected by the reflector plate 340 and then incident to the diffuser plate 320.

In this case, the diffusion plate 320 is divided into a region (hereinafter, A region) having a large amount of incident light and a region (hereinafter, B region) having a small amount of incident light. That is, a region corresponding to the effective light emitting region D of the lamp 330 of the diffusion plate 320 is a region having a large amount of incident light of the first light, and a region corresponding to the lamp and the lamp is relatively It is an area where the incident amount of the first light is small.

An optical path changing layer 360 is formed on the first surface 321 of the diffusion plate 320, that is, the incident surface on which the first light is incident. The light path changing layer 360 is divided into a protruding region 361 that is relatively thickly stacked from the first surface 321, and a concave region 362 that is relatively thinly stacked from the first surface 321. The protruding region 361 corresponds to the A region, and the concave region 362 corresponds to the B region. Here, the light path changing layer is made of a transparent material.

Among the first lights, light incident to the protruding region 361 is defined as third light, and light incident to the concave region 362 is defined as fourth light. In this case, the light path changing layer 360 reflects or refracts a portion of the third light at a predetermined angle and provides the light path changing layer 360 to the reflecting plate 340 side or to the diffusion plate 320 side. A part of the third light is light incident at an angle from an ordinary line perpendicular to the tangent line at each point of the protruding region 361. In this case, the reflected light is provided back to the diffusion plate 320 by the reflection plate 340, and the refracted light is directly provided to the diffusion plate 320.

As described above, the optical path changing layer 360 changes the traveling direction of the third light incident to the protruding region 361 to advance to another region. As a result, as the luminance of the region B is increased, the luminance difference generated between the region A and the region B is reduced. Thus, as shown in the third luminance distribution curve 370 shown in FIG. 4, the second light has a uniform luminance distribution.

In this case, it is preferable that the cross section of the optical path changing layer 360 has the same shape as the waveform of the first luminance distribution curve 160 shown in FIG. 1. The first luminance distribution curve 160 is measured in a state in which a printing pattern is not formed on the rear surface of the diffusion plate 320.

Referring to FIG. 3 again, a middle chassis 400 is disposed on the diffusion sheet 310. The middle chassis 400 fixes the diffusion plate 320 and the diffusion sheet 310 to the mold frame 350. That is, the middle chassis 400 is formed to have a rectangular band shape in which the second stepped portion 410 protruding from the inner wall is formed. Accordingly, the bottom surface of the second step 410 is in contact with the diffusion sheet 310 to press the diffusion plate 320 and the diffusion sheet 310 toward the mold frame 350.

Meanwhile, the liquid crystal display panel 510 is seated on an upper surface of the second step 410 of the middle chassis 400, and the data and gate printed circuit boards for controlling the driving of the liquid crystal display panel 510 are performed. 520 and 540 are bent to the outer surface of the mold frame 350 and fixed to the rear surface.

A top chassis having a cramped shape in which an upper and a lower surface of the liquid crystal display panel 510 is coupled to the mold frame 350 to fix the liquid crystal display panel 510 to the mold frame 350. 600). As a result, the direct type liquid crystal display 700 is completed.

Hereinafter, the manufacturing process of the light path changing layer 360 will be described in order to process the light path changing layer 360 to the same shape as the first luminance distribution curve 160.

5A and 5B are cross-sectional views illustrating a manufacturing process of forming an optical path changing layer on the back surface of the diffusion plate illustrated in FIG. 4.

Referring to FIG. 5A, an optical path changing material 365 is applied to a first surface 321 of the diffusion plate 320 to a predetermined thickness. Here, the light path change material 365 is preferably made of a material that is cured by ultraviolet light.

Thereafter, the light path change material 365 is patterned by the roller 370 patterned in a predetermined shape. In detail, the roller 370 includes a roller pillar 371 having a rod shape, and a pattern material 372 having a plurality of irregularities and surrounding the surface of the roller pillar 371. In this case, the pattern material 372 is patterned in the same form as the first luminance distribution curve 160.

Thereafter, the roller 370 is disposed on one end 365a of the light path changing material 365, and rotates toward the other end 365b facing the one end 365a. Pattern 365.

Thus, as shown in FIG. 5B, the light path changing layer 360 having a plurality of irregularities formed of the protruding region 361 and the concave region 362 is formed on the diffusion plate 320.

In this case, when ultraviolet rays (not shown) are irradiated to cure the optical path changing layer 360, the plurality of uneven shapes may be maintained for a predetermined period while the optical path changing layer 360 is cured.

FIG. 6 is a cross-sectional view illustrating a structure in which a scattering agent is formed in the light path changing layer illustrated in FIG. 4.

Referring to FIG. 6, a plurality of small particles made of a material having a refractive index different from that of the material constituting the light path changing layer 360, that is, a scattering agent 365, is formed inside the light path changing layer 360. .

In this way, the light path changing layer 360 has a light scattering property. Therefore, the light path changing layer 360 diffuses the first light through the scattering agent 365, thereby acting as the diffusion plate 320 and the diffusion sheet 310.

As a result, a structure in which any one of the diffusion plate 320 and the diffusion sheet 310 is omitted may be implemented. This sheet savings makes it possible to realize the thin and thin components of the direct type liquid crystal display device 700.

According to the liquid crystal display device described above, the light path changing member for changing the path of the first light is provided on the incident surface of the diffusion plate to which the first light from the light source is incident. In this case, the light path member is relatively thick in the first region corresponding to the light source, and relatively thin in the second region between the light sources. That is, a large number of irregularities are formed on the incident surface of the optical path changing member. The path of the first light incident on the first region is changed by the plurality of irregularities to advance to the second region.

Therefore, the luminance difference between the first region and the second region can be compensated for, and display characteristics of the liquid crystal display can be improved.

In addition, by not using a printing pattern that compensates for the difference in brightness by blocking light, the overall brightness of the liquid crystal display device may be increased, and the deterioration of display quality, which is caused by the deterioration of the printing pattern, may be prevented. .

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 (7)

A light source generating first light; A light diffusing member receiving the first light through a first surface and diffusing the first light into a second light having a uniform luminance distribution as a whole; The protruding region laminated at a relatively high height on the region where the incident amount of the first light is relatively high among the first surfaces, and the layer laminated at a relatively low height on the region where the incident amount of the first light is relatively low among the first surfaces. An optical path changing member having a concave region in which the first light is changed; And And a liquid crystal display panel configured to receive the second light to control the transmittance of the second light to display an image. The liquid crystal display of claim 1, wherein the protruding region is formed at a position facing the light source. The liquid crystal display of claim 2, wherein the protruding region extends to correspond to an effective light emitting region of the light source. The liquid crystal display device of claim 1, wherein the light diffusion member comprises a diffusion plate and a diffusion sheet disposed on an upper surface of the diffusion plate. The liquid crystal display of claim 4, wherein the first surface is a rear surface of the diffusion plate. The liquid crystal display of claim 1, wherein the light path changing member is made of a material that is cured by ultraviolet rays. The liquid crystal display device according to claim 1, wherein the light path changing member includes a scattering agent for scattering the first light.