KR20050097729A - Backlight assembly and liquid crystal display device using the same - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight assembly and a liquid crystal display device using the same to improve luminance non-uniformity by inserting reflective structures between light sources and to improve assembly efficiency and reduce production costs. A plurality of light sources to be generated, a plurality of reflective structures configured to reflect light generated from the light sources, and a diffuser plate positioned above the light sources and the reflective structures to diffuse light incident from the light sources And a reflecting plate positioned under the light source and the reflective structure to reflect light incident from the light source.

Description

Backlight assembly and liquid crystal display device using the same}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a backlight assembly and a liquid crystal display device using the same to improve brightness and productivity.

CRT (Cathode Ray Tube), one of the commonly used display devices, is mainly used for monitors such as TVs, measuring devices, information terminal devices, etc., but the miniaturization of electronic products due to the weight and size of CRT itself It was unable to actively respond to the demand for weight reduction.

Therefore, in the trend of miniaturization and weight reduction of various electronic products, CRT has a certain limit in weight and size, and is expected to replace the liquid crystal display device (LCD) and gas using electro-optic effects. Plasma display panels (PDPs) using discharge and EL display elements (ELDs) using electroluminescent effects have been studied. Among them, researches on liquid crystal displays have been actively conducted.

In order to replace the CRT, a liquid crystal display device having advantages such as small size, light weight, and low power consumption has recently been developed to be able to perform a sufficient role as a flat panel display device. As used in monitors and large information display devices, the demand for liquid crystal display devices continues to increase.

On the other hand, most of the liquid crystal display device is a light-receiving device that displays an image by adjusting the amount of light source coming from the outside, so a separate light source, that is, a back light, for irradiating light to the LCD panel is absolutely necessary. According to the position where the lamp unit is installed, it is divided into the edge method and the direct method.

The light source includes EL (Electro Luminescence), LED (Light Emitting Diode), CCFL (Cold Cathode Fluorescent Lamp), HCFL (Hot Cathode Fluorescent Lamp), etc., especially long life, low power consumption and thin can be formed. CCFL is widely used in large color TFT LCDs.

The CCFL light source uses a fluorescent discharge tube encapsulated at low pressure with a mercury gas containing argon, neon, or the like to take advantage of the penning effect. Electrodes are formed at both ends of the tube, and the cathode is formed in a wide plate shape.When voltage is applied, as in the sputtering phenomenon, charged particles in the discharge tube collide with the plate-shaped cathode to generate secondary electrons, which excite surrounding elements to excite the plasma. To form.

These elements emit strong ultraviolet light, which in turn excites the phosphor, causing the phosphor to emit visible light.

In the double-edge method, the lamp unit is installed on the side of the light guide plate for guiding the light, and the lamp unit surrounds the outer surface of the lamp and a lamp holder inserted into both ends of the lamp to protect the lamp and the lamp. The lamp reflector is mounted on the side of the light guide plate to reflect light emitted from the lamp toward the light guide plate.

The edge method in which the lamp unit is installed on the side of the light guide plate is applied to a relatively small liquid crystal display device such as a monitor of a laptop computer and a desktop computer, and has good uniformity of light and a long service life. It is advantageous to thin the liquid crystal display device.

On the other hand, the direct type method has been developed mainly as the size of the liquid crystal display device has increased to 20 inches or more, and a plurality of lamps are arranged in a row on the lower surface of the diffuser plate to direct light directly to the front of the LCD panel. will be.

The direct method is mainly used for a large screen liquid crystal display device requiring high luminance because the light utilization efficiency is higher than that of the edge method.

FIG. 1 is a perspective view illustrating a general direct backlight, and FIG. 2 is a view illustrating an electrode connection line connected to a general light emitting lamp and a connector.

As shown in FIG. 1, a plurality of light emitting lamps 1 having a phosphor coated on an inner surface thereof to emit light, an outer case 3 for fixing and supporting the light emitting lamps 1, and a light emitting lamp ( Light scattering means 5a, 5b, 5c disposed between 1) and a liquid crystal panel (not shown).

Wherein the light scattering means (5a, 5b, 5c) is to prevent the appearance of the light emitting lamp 1 on the display surface of the liquid crystal panel and to provide a light source having a uniform brightness distribution as a whole, to enhance the light scattering effect To this end, a plurality of diffusion sheets, diffusion plates, and the like are disposed between the liquid crystal panels.

In addition, a lamp reflector 7 is disposed on an inner surface of the outer case 3 so that the light emitted from the light emitting lamp 1 can be concentrated to the display unit of the liquid crystal panel, which is configured to maximize the use efficiency of light. do.

On the other hand, the light emitting lamp 1 is a cold cathode fluorescent lamp, as shown in Figure 2, the electrode (2, 2a) for electrically conducting to both ends inside the tube (Tube) is disposed, the electrode (2, 2a) When the power is applied, the light is emitted, and both ends of the light emitting lamp 1 are fitted into grooves formed on both sides of the outer case 3 as shown in FIG.

Electrode connection lines 9 and 9a to which external power for driving a lamp are applied are formed at both electrodes 2 and 2a of the light emitting lamp 1, and the electrode connection lines 9 and 9a are separate connectors 11. Is connected to the driving circuit. Therefore, a separate connector 11 is required for each light emitting lamp 1.

That is, an electrode connecting line 9 connected to one electrode 2 of the light emitting lamp 1 and an electrode connecting line 9a connected to the other electrode 2a are connected to one connector 11, and the electrode connecting line 9, Any one of 9a) is bent to the bottom of the outer case 3 and connected to the connector 11.

Hereinafter, a conventional backlight assembly will be described with reference to the accompanying drawings.

3 is a cross-sectional view of a conventional direct backlight assembly.

As shown in FIG. 3, the conventional backlight assembly includes a plurality of lamps 21 for generating light and a reflecting plate configured under the lamp 21 to reflect light generated from the lamp 21 upwards. (22), a diffusion plate (23) which is formed on the upper part of the lamp (21) to diffuse and emit the light generated by the lamp (21), and a diffusion sheet (24) placed on the diffusion plate (23). And a bottom plate 25 for storing them.

Here, the bottom plate 25 is formed in a box shape of a rectangular parallelepiped with an upper surface opened. A storage space having a predetermined depth is formed in the bottom plate 25, and a step for sequentially receiving the diffusion plate 23 and the diffusion sheet 24 is formed at an upper end of the side wall constituting the storage space.

In addition, the reflection plate 22 is installed along the inner surface of the storage space of the bottom plate 25, and a plurality of the lamps 21 are provided on the reflection plate 22 at regular intervals. In addition, the diffusion plate 23 and the diffusion sheet 24 are sequentially received in the stepped portion formed at the upper side end of the bottom plate 25.

At this time, a predetermined space (hereinafter, light guide area) is formed between the lamp 21 and the diffusion plate 23. As shown in FIG. 3, the light guide region is formed at a height of H1. As such, forming the light guiding region between the lamp 21 and the diffusion plate 23 widens the irradiation range of the light generated from the lamp 21 so as to be incident over the entire area of the diffusion plate 23. To guide.

In this case, a part of the light generated radially from the lamp 21 is incident directly to the diffusion plate 23, and a part of the light is reflected toward the diffusion plate 23 through the reflection plate 22. The light incident on the diffusion plate 23 is diffused and emitted to have a wide range of angles.

On the other hand, the diffusion sheet 24 placed on the diffusion plate 23 serves to diffuse to uniformize the luminance of the light emitted from the diffusion plate 23 toward the liquid crystal display panel.

However, in the above-described conventional direct type backlight assembly, as shown in the luminance distribution curve 26 shown in FIG. 3, the luminance of the light emitted from the light emitting region (hereinafter, A region) of the lamp 21 is determined by the lamp and the lamp. It is relatively higher than the luminance of light emitted from the area in the following (hereinafter referred to as the B area). Thus, luminance unevenness occurs between the A area and the B area.

The present invention has been made to solve the above problems, by inserting a reflective structure between the light source to improve the luminance non-uniformity, and to improve the assembly efficiency and reduce the production cost, and a liquid crystal display device using the same The purpose is to provide.

The backlight assembly according to the present invention for achieving the above object is a plurality of light sources arranged at regular intervals to generate light, and a plurality of reflective structures configured between each of the light sources to reflect the light generated from the light source And a diffuser plate positioned above the light source and the reflective structure to diffuse light incident from the light source, and a reflector plate positioned below the light source and the reflective structure to reflect light incident from the light source. It features.

In addition, the liquid crystal display device having a backlight assembly of the present invention for achieving the above object is a plurality of light sources for generating light and a plurality of reflective structures configured between each of the light sources, and on the light source and the reflective structure A backlight assembly positioned at an upper portion of the backlight assembly, the backlight assembly being integrally formed with the reflective structure and having a bottom plate configured to receive the respective light sources and the diffusion plates. And a liquid crystal display panel assembly configured to display an image by receiving light from the backlight assembly.

Hereinafter, the backlight assembly according to the present invention will be described in detail with reference to the accompanying drawings.

4 is a plan view showing a backlight assembly according to the present invention.

As shown in FIG. 4, a plurality of light sources 330 are arranged at regular intervals to generate light, and the light generated from the light sources 330 is disposed between the light sources 330 to both left and right sides. A plurality of reflective structures 340 for reflecting, a reflecting plate 360 configured at a lower end of the light source 330 and the reflective structure 340 to reflect light generated from the light source 330 upwardly, and the reflective structure The bottom plate 350 is formed integrally with one side of the 340 and accommodates the light source 330 and the reflecting plate 360.

Here, the reflective structure 340 corresponding to each of the light sources 330 has a multi-faceted reflecting surface, and the bottom plate is located on the side which is symmetrical with respect to each light source 330 with respect to each reflecting area. It is integrally connected to one side guide of the 350.

In addition, the reflective structure 340 is arranged on the reflective plate 360 made of a white foam resin plate to have a predetermined distance in the longitudinal direction of the light source 330 between the light source 330 and the light source 330 Although reflecting surfaces are formed to reflect the light generated at 330 to both the left and right sides, the reflecting surface is integrally mounted to the reflecting plate 360 made of an aluminum plate, a synthetic resin plate, or the like, so that the processing is appropriately performed. In some embodiments, the reflective structure 340 may be formed.

In the backlight assembly according to the present invention, the reflective structure 340 is integrally formed with the guide of the bottom plate 350 to improve the assembly efficiency, and the assembly process is cumbersome and complicated by facilitating the manufacturing of the reflective plate 360. The shortcomings were improved and the shape itself could be simplified to simplify the assembly process and improve the reflection efficiency.

The reflective structure 340 may be formed in various shapes such as a triangle or a sphere (or an ellipse).

FIG. 5 is a cross-sectional view illustrating a backlight assembly having a reflective structure having a triangular shape in FIG. 4.

As shown in FIG. 5, the backlight assembly according to the present invention includes a plurality of light sources 330 arranged at regular intervals to generate light, and are configured in a triangular form between the light sources 330. A plurality of reflective structures 340 for reflecting the light generated by the 330 to the left and right sides, and the light source 330 and the lower end of the reflective structure 340 is configured to reflect the light generated from the light source 330 to the upper side A reflection plate 360, an upper portion of the light source 330, a diffuser plate 320 which diffuses and emits the light generated by the light source 330, and an integral part of one side of the reflective structure 340. And a diffusion sheet 310 disposed on the diffusion plate 320 and a bottom plate 350 for storing the diffusion sheet 310.

Here, the bottom plate 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 inside the bottom plate 350, and a step for sequentially receiving the diffusion plate 320 and the diffusion sheet 310 is formed at an upper end of the side wall constituting the storage space.

In addition, the reflecting plate 360 is installed along the inner surface of the storage space of the bottom plate 350, and a plurality of light sources 330 are provided on the reflecting plate 360 at regular intervals. In addition, a diffusion plate 320 and a diffusion sheet 310 are sequentially received in the stepped portion formed at the upper side end of the bottom plate 350.

In this case, a predetermined space (hereinafter, light guide area) is formed between the light source 330 and the diffusion plate 320. As shown in FIG. 5, the light guide region is formed at a height of H1. As such, forming the light guiding region between the light source 330 and the diffuser plate 320 widens the irradiation range of the light generated from the light source 330 to be incident over the entire area of the diffuser plate 320. To guide.

In addition, a part of the light generated radially from the light source 330 is directly incident to the diffuser plate 320, and part of the light is reflected toward the diffuser plate 320 through the reflector plate 360. The light incident on the diffusion plate 320 is diffused and emitted to have a wide range of angles.

In addition, the light source 330 uses a cold cathode fluorescent lamp or an external electrode fluorescent lamp.

In addition, the diffusion sheet 310 has two sheets of diffusion sheets stacked in a direction perpendicular to each other.

On the other hand, the diffusion sheet 310 placed on the diffusion plate 320 serves to diffuse to uniformize the brightness of the light emitted from the diffusion plate 320 toward the liquid crystal display panel.

Therefore, the backlight assembly according to the present invention, as shown in the luminance distribution curve 370 shown in Figure 5, the luminance of the light emitted from the light emitting region (hereinafter, A region) of the light source 330 and the light source 330 and The luminance of light emitted from the region between the light sources 330 (hereinafter, B region) effectively reflects the light directed toward the bottom by the reflective structure 340, so that the luminance distribution between the A region and the B region is uniform. .

6 is a cross-sectional view illustrating a backlight assembly having a reflective structure having a spherical shape in FIG. 4.

As shown in FIG. 6, a plurality of light sources 330 arranged at regular intervals to generate light, and each of the light sources 330 are formed in a spherical or elliptical shape and are generated by the light sources 330. A plurality of reflective structures 340 for reflecting light to the left and right sides, and a reflecting plate 360 configured at the lower end of the light source 330 and the reflective structure 340 to reflect the light generated from the light source 330 to the upper side And a diffuser plate 320 which is configured on the light source 330 to diffuse and emit light generated from the light source 330, and is integrally formed with the reflective structure 340 and is diffused into the diffuser plate 320. The diffusion sheet 310 is placed thereon and a bottom plate 350 for receiving them.

On the other hand, the reflective structure 340 is

{x ^ 2 over a ^ 2} + {y ^ 2 over b ^ 2} = 1, a = b has a spherical shape, and a ≠ b has an elliptical shape.

7 is an exploded perspective view illustrating a liquid crystal display device having a direct type backlight assembly according to an exemplary embodiment of the present invention.

As shown in FIG. 7, a liquid crystal display panel assembly 500 for displaying an image, a direct type backlight assembly 300 for supplying light to the liquid crystal display panel assembly 500, and the backlight assembly 300. And a top case 600 formed in a rectangular band having a flat portion and a side portion bent at right angles to surround the edge of the liquid crystal display panel assembly 500. .

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 530, and a gate tape carrier package 550. Include.

In addition, the liquid crystal display panel 510 includes a TFT substrate 511, a color filter substrate 513 positioned on the TFT substrate 511, and a liquid crystal (not shown) injected between the two substrates 511 and 513. do.

Here, a thin film transistor (not shown) that performs a switching role is formed on the TFT substrate 511, a gate line is connected to a gate electrode of each thin film transistor, and a data line is connected to a source electrode. The pixel electrode is formed on the drain electrode.

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 tape carrier package 530 and the gate tape carrier package 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 control signal are transmitted to the gate line and the data line through the data tape carrier package 530 and the gate tape carrier package 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. Accordingly, 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 of the thin film transistor to change the arrangement of liquid crystals therebetween.

Meanwhile, as described above with reference to FIGS. 4 to 6, the backlight assembly includes a plurality of light sources 330 arranged at regular intervals, and are formed in a triangular or spherical (or elliptical) shape between the light sources 330. A plurality of reflective structures 340 for reflecting the light generated by the light source 330 to the left and right sides, and the lower end of the light source 330 and the reflective structure 340 to generate the light generated from the light source 330 Integral with the reflective plate 360 to reflect upward, the diffusion plate 320 is formed on the light source 330 to diffuse and emit the light generated by the light source 330, and the reflective structure 340 The diffusion sheet 310 is made and placed on the diffusion plate 320 and the bottom plate 350 for receiving them.

The bottom plate 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 inside the bottom plate 350, and a stepped portion in which the diffusion plate 320 and the diffusion sheet 310 are sequentially seated is formed at an upper end portion of the side wall constituting the storage space.

In addition, the bottom plate 350 for accommodating the light source 330, the diffusion plate 320, and the diffusion sheet 310 is provided as an embodiment of the present invention, and other types of frames as well as molds may be applied. have.

The reflection plate is installed along the inner surface of the storage space of the bottom plate 350, and a plurality of light sources 330 are installed on the reflection plate. In this case, opposite ends of the light source 330 are respectively coupled to the lamp holder 380 to stably fix the plurality of light sources 330 to the top of the bottom plate 350.

As described above, when the reflecting plate 340, the light source 330, the diffusion plate 320, and the diffusion sheet 310 are sequentially received in the bottom plate 350, a middle chassis 400 is provided thereon. The diffusion plate 320 and the diffusion sheet 310 are fixed to the bottom plate 350.

That is, the middle chassis 400 is formed to have a rectangular band shape with a stepped protrusion protruding from the inner wall. Therefore, the lower surface of the step is interviewed with the diffusion sheet 310 to press them downward from above to fix the diffusion plate 320 and the diffusion sheet 310 to the bottom plate 350.

Meanwhile, the liquid crystal display panel 510 is seated at a step of the middle chassis 400, and the data and gate printed circuit boards 520 and 540 for controlling driving of the liquid crystal display panel 510 are bottomed. The outer surface of the plate 350 is bent and fixed to the rear surface.

On the other hand, the present invention described above is not limited to the above-described embodiment and the accompanying drawings, it is possible that various substitutions, modifications and changes within the scope without departing from the technical spirit of the present invention. It will be apparent to those of ordinary skill in Esau.

As described above, the backlight assembly and the liquid crystal display using the same according to the present invention have the following effects.

First, the reflector structure may be integrally attached to one side of the bottom plate between the light sources in the backlight assembly, thereby improving assembling and facilitating the manufacture of the reflector.

Second, the light that enhances the bottom surface of the light generated by the light source is reflected on the reflective structure surface to maximize the light utilization efficiency of the light source while maintaining the uniformity of brightness between the light source and the light source, thereby improving the brightness of the liquid crystal display device. have.

Third, by forming the reflective structure in the shape of a sphere, the number of light sources can be reduced, and the light source visible phenomenon can be eliminated.

Fourth, the light emitted from the light source can be spread evenly over a large area, thereby making the screen brightness of the liquid crystal display device uniform, thereby achieving a uniform brightness distribution even in a large area.

1 is a perspective view showing a general direct backlight

2 is a view illustrating an electrode connection line connected to a general light emitting lamp and a connector;

3 is a cross-sectional view showing a conventional direct type backlight assembly.

4 is a plan view showing a backlight assembly according to the present invention;

FIG. 5 is a cross-sectional view illustrating a backlight assembly having a reflective structure having a triangular shape in FIG. 4. FIG.

FIG. 6 is a cross-sectional view illustrating a backlight assembly having a spherical reflective structure in FIG. 4; FIG.

7 is an exploded perspective view illustrating a liquid crystal display device having a direct type backlight assembly according to an exemplary embodiment of the present invention.

Explanation of symbols for the main parts of the drawings

310: diffusion sheet 320: diffusion plate

330 light source 340 reflective structure

350: bottom plate 360: reflector

370: luminance distribution curve 380: lamp holder

Claims (9)

A plurality of light sources arranged at regular intervals to generate light, A plurality of reflective structures configured between each of the light sources to reflect light generated from the light sources; A diffuser plate positioned on the light source and the reflective structure to diffuse light incident from the light source; And a reflecting plate positioned below the light source and the reflective structure to reflect light incident from the light source. The backlight assembly of claim 1, wherein the reflective structure has any one of a triangular shape, a spherical shape, and an oval shape and is arranged in the longitudinal direction of the light source. The backlight assembly of claim 1, further comprising a bottom plate to which one side of the reflective structure is attached and to receive the light source and the diffusion plate.  The backlight assembly of claim 1 or 3, wherein the reflective structure is integrally attached to the side of the bottom plate.  The backlight assembly according to claim 1, wherein the reflecting plate is made of any one of a white foamed resin plate, an aluminum plate, or a synthetic resin plate.  The backlight assembly of claim 1, further comprising a diffusion sheet configured on the diffusion plate to uniformly diffuse luminance of light emitted from the diffusion plate.  7. The backlight assembly of claim 6, wherein the diffusion sheet is composed of two diffusion sheets which diffuse in a direction perpendicular to each other.  The backlight assembly of claim 1, wherein the light source is a cold cathode fluorescent lamp or an external electrode fluorescent lamp. A plurality of light sources for generating light and a plurality of reflective structures formed between the light sources, a diffuser plate positioned above the light sources and the reflective structures to diffuse light incident from the light sources, and integrally with the reflective structures A backlight assembly made of a bottom plate for receiving each light source and the diffusion plate; And a liquid crystal display panel assembly positioned on the backlight assembly and configured to display an image by receiving light from the backlight assembly.