KR20040079237A - Backlight assembly - Google Patents

Abstract

PURPOSE: A back light assembly is provided to decrease the size of a liquid crystal display including the back light assembly. CONSTITUTION: A back light assembly includes a light guide(720), a lamp unit(750), the first electrode line and the second electrode line. The lamp unit includes a lamp(751) for generating light and a lamp cover(753) for protecting the lamp. The first electrode line is connected to one end of the lamp to provide the first power. The second electrode line is connected to the other end of the lamp to provide the second power. The second electrode line is located under a reflecting plane of the light guide along one side of the lamp cover.

Description

Backlight Assembly {BACKLIGHT ASSEMBLY}

The present invention relates to a backlight assembly, and more particularly to a backlight assembly for reducing the overall size.

1 is a cross-sectional view of a liquid crystal display device employing a conventional backlight assembly.

Referring to FIG. 1, the liquid crystal display device 1000 includes a display unit 20 including a liquid crystal display panel 21 for displaying an image and a backlight unit 30 for supplying uniform light to the display unit 20. Has

The display unit 20 includes a liquid crystal display panel 21 for displaying an image and driving circuit boards 22 and 23 for driving the liquid crystal display panel 21. The liquid crystal display panel 21 includes a TFT substrate 27 having a thin film transistor (hereinafter, referred to as TFT) (not shown) and a pixel electrode, a color filter substrate 28 having an RGB pixel and a common electrode, and a TFT substrate. And a liquid crystal (not shown) located between the 27 and the color filter substrate 28.

A plurality of gate lines (not shown) extending in the row direction and a plurality of data lines (not shown) extending in the column direction are formed in the TFT substrate 27. Here, the gate electrode of the TFT is connected to the gate line, and the source electrode of the TFT is connected to the data line. The drain electrode of the TFT is combined with the pixel electrode.

In addition, the backlight unit 30 may include a lamp 37 generating light, a light source unit 31 having a lamp cover 38 covering one side of the lamp 37, and guiding the light toward the liquid crystal display panel 21. The light guide plate 32 is provided. Here, the lamp 37 and the lamp cover 38 are provided on the side of the light guide plate 32.

Hot electrodes (not shown) for applying a high voltage and ground electrodes 39 for providing a low voltage are respectively connected to both ends of the lamp 37 accommodated in the lamp cover 38, and lamps 37 are connected to these connection portions. Lamp holder (not shown) for holding the position of the is installed.

On the other hand, the light guide plate 32 propagates the light from the lamp 37 toward the liquid crystal display panel 21 placed above the light guide plate 32.

Under the light guide plate 32, a reflecting plate 34 for reflecting the light leaking without being reflected by the dot pattern of the light guide plate 32 toward the light guide plate 32 is provided. Above the light guide plate 32, a plurality of optical sheets 33 are arranged to have a uniform brightness distribution of light emitted from the light guide plate 32 with a non-uniform brightness distribution.

The display unit 20 and the backlight unit 30 configured as described above are accommodated in the bottom chassis 12 and the mold frames 40 and 50. Specifically, the bottom chassis 12, the reflecting plate 34, the light guide plate 32, and the plurality of optical sheets 33 are sequentially stored in the mold frame 40. Thereafter, the liquid crystal display panel 21 is seated on the plurality of optical sheets 33.

The liquid crystal display 1000 may be coupled to face the mold frame 40 to include a top chassis 11 for fixing the display unit 20 and the backlight unit 30.

In a typical side light guide type backlight assembly, a lamp is provided on a side of the light guide plate, and the printed circuit board is bent and received by the bottom of the mold frame. Therefore, the bezel BB of the liquid crystal display device is widened by the minimum space required when the lamp is disposed on the side surface, and the thickness of the liquid crystal display device is increased as the printed circuit board is disposed under the lamp. As a result, an increase in the size of the liquid crystal display device cannot be prevented.

That is, in the structure of the conventional backlight assembly having a lamp on the side of the light guide plate, there is a problem that the overall size of the liquid crystal display device is increased.

SUMMARY OF THE INVENTION An object of the present invention for solving the above problems is to provide a backlight assembly for reducing the size.

1 is a cross-sectional view of a liquid crystal display device employing a conventional backlight assembly.

2 is an exploded perspective view of a liquid crystal display device employing a backlight assembly according to a first embodiment of the present invention.

3 is a cross-sectional view of the liquid crystal display shown in FIG. 2.

4 is a view illustrating a receiving structure of the backlight assembly illustrated in FIG. 2.

5A is a perspective view illustrating a light guide plate employed in a backlight assembly according to a second exemplary embodiment of the present invention.

FIG. 5B is a view illustrating the bottom of the backlight assembly illustrated in FIG. 5A.

6 is a perspective view illustrating a coupling structure of a backlight assembly according to a third exemplary embodiment of the present invention.

7 is a perspective view illustrating a coupling structure of a backlight assembly according to a fourth exemplary embodiment of the present invention.

<Explanation of symbols for main parts of the drawings>

700: backlight assembly 751: lamp

753 lamp cover 750 lamp unit

230: printed circuit board 720, 820, 920, 1020: light guide plate

730 optical sheet 740: reflector

400: mold frame 150: bottom chassis

755: electrode wire

In order to realize the above object of the present invention, a backlight assembly includes a light guide plate, a lamp unit, a first electrode line, and a second electrode line. The lamp cover has a lamp for generating light and a lamp cover for protecting the lamp, and the first electrode line is connected to one end of the lamp to supply a first power source. In addition, the second electrode line is connected to the other end of the lamp to supply a second power source, and in particular, is stored below the reflective surface of the light guide plate along one side of the lamp cover.

According to another aspect of the present invention, a backlight assembly includes a light guide plate and a lamp for guiding light. In particular, the light guide plate has a groove for accommodating the lamp.

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

2 is an exploded perspective view of a liquid crystal display device employing a backlight assembly according to a first embodiment of the present invention, Figure 3 is a cross-sectional view of the liquid crystal display device shown in Figure 2, Figure 4 is a backlight assembly shown in FIG. It is a figure which shows the accommodating structure of this.

2, 3, and 4, the liquid crystal display device 2000 supplies uniform light to the display unit 200 and the display unit 200 including the liquid crystal display panel 210 for displaying an image. To have a backlight assembly 750.

The liquid crystal display 200 performs a display using a liquid crystal whose light transmittance is changed according to an electric field.

In this case, a backlight assembly for supplying light to the liquid crystal display panel is provided. The backlight assembly 750 is mounted on the lamp 751 that generates light, the lamp cover 753, the light guide plate 720 that guides the light to the display unit 200, and the light guide plate 720. Optical sheet 730 for adjusting the viewing angle of light from the light guide plate) and a reflecting plate 740 for reflecting the light leaked from the light guide plate 720 back to the light guide plate 7200.

A cold cathode tube is mainly used for the lamp 751, and the light generated from the lamp 751 is incident through the light guide plate 720. A reflection member is formed on an inner surface of the lamp cover 753, and the lamp cover 753 reflects light toward the light guide plate 720 to improve the efficiency of the light.

The lamp 751 is provided below the light guide plate 720. Therefore, when the lamp 751 is disposed on the side surface of the light guide plate 720, the bezel NB is narrowed because it is not necessary to secure a necessary space.

Further, hot electrodes (not shown) for applying a high voltage and ground electrodes 755 for providing a low voltage are connected to both ends of the lamp 751 housed in the lamp cover 753.

The hot electrode and the ground electrode 755 for receiving an external power supply to the lamp 751 are connected to a connector (not shown) outside one side of the mold frame 400. In this case, the ground electrode 755 may be accommodated in a space generated by the lamp 751 provided below the light guide plate 720, thereby preventing the size of the liquid crystal display device 2000 from increasing.

To this end, the ground electrode 755 is accommodated while being bent from one end of the lamp 751 to the lower side of the light guide plate 720, in which case the ground electrode 755 is easily accommodated in the mold frame 400. The mold frame 400 includes a groove 757 through which the ground electrode 755 passes.

Meanwhile, the display unit 200 includes a liquid crystal display panel 210 for displaying an image and driving circuit boards 220 and 230 for driving the liquid crystal display panel 210. The liquid crystal display panel 210 includes a TFT substrate 211 having a TFT (not shown) and a pixel electrode (not shown), a color filter substrate 213 having a RGB pixel and a common electrode, and a TFT substrate 211 and a color. Liquid crystal (not shown) positioned between the filter substrate and 213.

The display unit 200 includes a liquid crystal display panel 210, a data printed circuit board 220, a gate printed circuit board 230, a data side tape carrier package (hereinafter referred to as TCP) 240, and a gate side. TCP 250 is included. The liquid crystal display panel 210 includes a thin film transistor (hereinafter, referred to as TFT) substrate 211, a color filter substrate 213, and a liquid crystal (not shown).

The TFT substrate 211 is a transparent glass substrate on which a matrix TFT (not shown) is formed. A data line is connected to a source terminal of the TFTs, and a gate line is connected to a gate terminal. In addition, a pixel electrode made of indium tin oxide (ITO), which is a transparent conductive material, is formed in the drain terminal. When an electrical signal is input to the data line and the gate line, an electrical signal is input to the source terminal and the gate terminal of each TFT, and the TFT is turned on or turned off according to the input of these electrical signals to the drain terminal. Electrical signals necessary for pixel formation are output.

The color filter substrate 213 is provided opposite to the TFT substrate 211. The color filter substrate 213 is a substrate in which RGB pixels, which are color pixels in which a predetermined color is expressed while light passes, are formed by a thin film process. The front surface of the color filter substrate 213 is coated with a common electrode made of ITO.

When power is applied to the gate terminal and the source terminal of the transistor of the above-described TFT substrate 211 and the TFT is turned on, an electric field is formed between the pixel electrode and the common electrode of the color filter substrate. By this electric field, the arrangement angle of the liquid crystal injected between the TFT substrate 211 and the color filter substrate 213 is changed, and the light transmittance is changed according to the changed arrangement angle to obtain a desired pixel.

As shown, a data side TCP 240 for determining when to apply a data driving signal is attached to a source side of the liquid crystal display panel 210, and a gate side TCP for determining a timing for applying a driving signal of a gate to the gate side. 250 is attached. The data printed circuit board 240 is connected to the data side TCP 240 to receive an image signal from the outside of the liquid crystal display panel 210 and apply a driving signal to the data line. The gate printed circuit board 230 is connected to the gate side TCP 250 to apply a driving signal to the gate line.

On the other hand, a reflector plate 740 is provided below the light guide plate 720 to reflect the light leaked without being reflected by the printed pattern of the light guide plate 720 toward the light guide plate 720. Above the light guide plate 720, a plurality of optical sheets 730 are disposed to have a uniform brightness distribution of light emitted from the light guide plate 720 with a non-uniform brightness distribution.

FIG. 5A is a perspective view illustrating a light guide plate employed in a backlight assembly according to a second exemplary embodiment of the present invention, and FIG. 5B is a bottom view of the backlight assembly illustrated in FIG. 5A.

Referring to FIG. 5A, the light guide plate 820 employed in the second embodiment includes a bottom surface 821, an upper surface 826, and first, second, third, and fourth side surfaces 822, 823, 824, and 825. Is done.

The bottom surface 821 has a reflecting surface 821b and an incident surface 821a, and the top surface 826 is a surface facing the bottom surface 821. Here, the reflective surface 821b can be assumed to be a surface extending the incident surface 821a.

The first side surface 822 is an inclined surface that is inclined toward the incident surface 821a. By employing such an inclined structure, the efficiency of light emitted to the liquid crystal display panel side can be improved.

The second side surface 823 faces the first side surface 822. The third side 824 also connects the first and second sides 822, 723, and the fourth side 825 faces the third side 824.

In detail, the lamp unit 750 is disposed at the lower side of the incident surface 821a of the bottom surface 821 so that light is incident, and the reflective surface 821b of the bottom surface 821 reflects the light to the top surface 826.

Although FIG. 5A illustrates that the lamp unit 750 is provided below one entrance surface, the case in which the lamp unit is provided on two or more surfaces also falls within the scope of the present invention. I can understand.

As shown in FIG. 5B, the lamp unit 750 is disposed under the surface IA corresponding to the incident surface 821a to enter light, and the surface RA corresponding to the reflective surface 821b receives light. It serves to reflect.

6 is a perspective view illustrating a coupling structure of a backlight assembly according to a third exemplary embodiment of the present invention.

Referring to FIG. 6, the light guide plate 920 employed in the third embodiment of the present invention includes a bottom surface 921 having an incident surface 921a and a reflective surface 921b, and an upper surface 926 facing the bottom surface 921. And side surfaces connecting the bottom surface 921 and the top surface 926.

As in the other exemplary embodiment described above, the lamp unit 750 is provided under the incident surface 921a of the light guide plate 920. In particular, the light guide plate 920 employed in the third embodiment has a protrusion 925 protruding from the reflective surface on the incident surface 921a of the light guide plate 920.

That is, since the protrusion 925 of the light guide plate 920 is inserted into the lamp cover 753 having the lamp 752, the light efficiency of the backlight assembly is improved. Specifically, by forming the protrusion 925 on the light guide plate 920, the number of reflections of the light generated by the lamp 752 is increased to have a uniform luminance distribution.

A cold cathode tube is mainly used for the lamp 751, and the light generated from the lamp 751 is incident through the light guide plate 720. A reflection member is formed on an inner surface of the lamp cover 753, and the lamp cover 753 reflects light toward the light guide plate 720 to improve the efficiency of the light.

The lamp 751 is provided below the light guide plate 720. Therefore, when the lamp 751 is disposed on the side of the light guide plate 720, since the space of the side of the light guide plate does not need to be secured, the bezel NB is narrowed, thereby reducing the size of the liquid crystal display.

7 is a perspective view illustrating a coupling structure of a backlight assembly according to a fourth exemplary embodiment of the present invention.

Referring to FIG. 7, the light guide plate 1020 employed in the fourth embodiment of the present invention faces the bottom surface 1021 and the bottom surface 1021 having the first incident surface 1021a and the first reflective surface 1021b. An upper surface 1026 having a second incident surface 1026a and a second reflective surface 1026b, and side surfaces connecting the bottom surface 1021 and the upper surface 1026.

In particular, it has a first groove 1050a for accommodating the first lamp 852a in the first incident surface 1021a, and has a second incident surface 1026a opposite the first incident surface 1021a.

The second entrance face 1026a also has a second groove 1050b for accommodating the second lamp 852b.

Since the first groove 1050a and the second groove 1050b are provided, the size of the final liquid crystal display device is not required because the bezel or the thickness of the liquid crystal display device increased due to the reception of the lamps 852a and 852b. In addition to the reduction, the storage of the lamps 852a and 852b is facilitated.

In addition, a lamp cover 853 is provided to surround both the first and second lamps 852a and 852b and the first and third incidence surfaces 1021a and 1026a.

Compared to employing a lamp cover that covers the first and second lamps 851a and 851b, respectively, it is preferable to employ a lamp cover 853 that covers both the first and second lamps 851a and 851b as in the above case. It is advantageous for ensuring the uniformity of light.

According to the backlight assembly described above, the lamp unit is disposed on the lower side of the light guide plate so that the overall size can be reduced by bending and accommodating the lamp electrodes in the resulting space.

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

Claims (9)

A light guide plate including a bottom surface having a reflective surface and an incident surface, an upper surface facing the bottom surface, and a side surface connecting the bottom surface and the upper surface; A lamp unit provided below the incident surface of the light guide plate and having a lamp for generating the light and a lamp cover for covering the lamp; A first electrode wire connected to one end of the lamp to supply a first power source; And A second electrode wire connected to the other end of the lamp to supply a second power source and extending toward the first electrode line; The second electrode line is a backlight assembly, characterized in that stored below the reflective surface of the light guide plate along one side of the lamp cover. The backlight assembly of claim 1, wherein at least one of the side surfaces of the light guide plate is inclined toward the incident surface of the bottom surface. The backlight of claim 1, wherein the first electrode line is a high voltage electrode line for applying a high voltage to one end of the lamp, and the second electrode line is a low voltage electrode line for maintaining the other end of the lamp in a ground state. assembly. The backlight assembly of claim 1, wherein the incident surface of the light guide plate has a protrusion protruding from the reflective surface. The backlight assembly of claim 4, wherein the protrusion is inserted into the lamp cover. A light guide plate comprising a bottom surface having a reflective surface and a first incident surface, an upper surface facing the bottom surface, and a side surface connecting the bottom surface and the top surface; And A first lamp provided below the first incident surface of the light guide plate to generate the light; And the first incident surface of the light guide plate has a first groove for accommodating the first lamp. The backlight assembly of claim 6, further comprising a second lamp provided on an upper side of the second incident surface facing the first incident surface of the light guide plate. 8. The backlight assembly of claim 7, wherein the second incident surface has a second groove for receiving a second lamp. The backlight assembly of claim 7, further comprising a lamp cover integrally provided to cover the first and second lamps.