KR20070015657A - Backlight unit and liquid crystal display device having the same - Google Patents

Abstract

The present invention relates to a backlight unit and a liquid crystal display including the same. The backlight unit according to the present invention comprises an optical plate; A plurality of lamps positioned on a rear surface of the optical plate; A supporter having a support portion for supporting the optical plate, a fixing portion for fixing the lamp, and a hook formed on a rear surface thereof; And a bottom chassis in which a hook insertion hole into which the hook is inserted and a cap part for blocking at least a portion of the hook are formed. This provides a backlight unit that is uniform in brightness and capable of protecting the supporter from external shocks.

Description

BACKLIGHT UNIT AND LIQUID CRYSTAL DISPLAY DEVICE HAVING THE SAME}

1 is an exploded perspective view of a liquid crystal display according to a first embodiment of the present invention;

2 is a perspective view of an essential part of a liquid crystal display device according to a first embodiment of the present invention;

3 and 4 are cross-sectional views of main parts of a liquid crystal display according to a first embodiment of the present invention, and

5 is a cross-sectional view illustrating main parts of a liquid crystal display according to a second exemplary embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

10: upper chassis 20: liquid crystal display panel

25 drive unit 30 backlight unit

35 optical plate 40 light source

51: side mold 53: middle mold

60: supporter 61: main body

62: support portion 63: fixed portion

64, 65 hook 66, 67 binding part

70: reflector 80: bottom chassis

81: hook insertion hole 82, 85: cap

83: coupling hole 84: coupling jaw

The present invention relates to a backlight unit and a liquid crystal display, and more particularly, to a direct type backlight unit having a supporter for holding and fixing a lamp and an optical plate, and a liquid crystal display including the same.

The liquid crystal display device includes a thin film transistor substrate, a color filter substrate, and a liquid crystal display panel in which liquid crystal is injected between both substrates. Since the liquid crystal display panel is a non-light emitting device, a backlight unit for supplying light is disposed on the rear surface of the thin film transistor substrate. Light transmitted from the backlight unit is adjusted according to the arrangement of liquid crystals.

The backlight unit includes a light source for generating light and an optical plate for controlling the light incident from the light source and sending the light to the liquid crystal display panel.

The backlight unit is divided into an edge type and a direct type according to the position of the light source. The direct type is a structure mainly developed as the size of the liquid crystal display device is enlarged. The direct type is a structure in which one or more light sources are arranged on the lower surface of the liquid crystal display panel to supply light to the liquid crystal display panel. As a light source of the direct type backlight unit, a line light source such as a cold cathode fluorescent lamp (CCFL) is used together with an external electrode fluorescent lamp (EEFL).

The optical plate diffuses and collects light from a light source and supplies the light to the liquid crystal display panel, and includes an optical film such as a prism film and a protective film positioned on the diffusion plate and the diffusion plate.

Recently, as the size of liquid crystal displays increases, the length of the direct type linear light source is also getting longer and the size of the optical plate is also increasing. Accordingly, there is a problem that the center portion of the line light source and the optical plate sag due to the load. In order to solve this problem, a supporter, which is a support member for supporting the lamp and the optical plate, is disposed on the bottom of the bottom chassis to fix the lamp and support the optical plate. The supporter is fixed to the bottom chassis by the wing part of the hook protruding to the outside of the bottom chassis through the hook through hole formed in the reflector plate and the bottom chassis.

However, the supporter has a different material from the reflector and has a problem of luminance unevenness in which a part of the supporter appears as a dark part on the screen due to the low reflectance. In addition, there is a problem that the luminance unevenness becomes more severe as the supporter made of white resin discolors with time due to ultraviolet rays generated from the lamp. On the other hand, the hook that protrudes to the outside of the bottom chassis is exposed to external impact, and when the shock is received during handling, the shock is transmitted to the lamp and the optical plate fixed by the supporter through the supporter, thereby damaging the light source and the optical plate. have.

Accordingly, an object of the present invention is to provide a backlight unit that is uniform in luminance and capable of protecting the supporter from external shock.

Another object of the present invention is to provide a liquid crystal display device including a backlight unit which is uniform in brightness and protects the supporter from external impact.

The object is, in accordance with the present invention, an optical plate; A plurality of lamps positioned on a rear surface of the optical plate; A supporter having a support portion for supporting the optical plate, a fixing portion for fixing the lamp, and a hook formed on a rear surface thereof; It is achieved by a backlight unit including a bottom chassis in which a hook insertion hole into which the hook is inserted and a cap part for blocking at least a portion of the hook is formed.

The supporter is preferably made of any one of polymethyl methacrylate (PMMA), polycarbonate (PC), polyethylene terephthalate (PET) of the transparent material in order to increase the uniformity of the brightness.

The cap portion preferably further includes a coupling hole coupled to the hook to protect the supporter.

It is preferable that the cap portion further includes a coupling jaw engaged with the hook to protect the supporter.

Another object of the present invention is a liquid crystal display panel; An optical plate positioned on a rear surface of the liquid crystal display panel; A plurality of lamps positioned on a rear surface of the optical plate; A supporter having a support portion for supporting the optical plate, a fixing portion for fixing the lamp, and a hook formed on a rear surface thereof; And a bottom chassis having a hook insertion hole into which the hook is inserted and a cap portion for blocking at least a portion of the hook.

The cap unit preferably further includes a coupling hole coupled to the hook.

The cap portion preferably further includes a coupling jaw coupled to the hook.

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

In various embodiments, like reference numerals refer to like elements, and like reference numerals refer to like elements in the first embodiment and may be omitted in other embodiments.

A liquid crystal display according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 4. 1 to 4 are exploded perspective views, recessed perspective views and recessed sectional views of the liquid crystal display according to the first embodiment of the present invention, respectively.

The liquid crystal display device includes a liquid crystal display panel 20 that forms an image, a driver 25 provided on one side of the liquid crystal display panel 20, and a backlight unit 30 disposed on a rear surface of the liquid crystal display panel 20.

The liquid crystal display panel 20 bonds the thin film transistor substrate 21 on which the thin film transistor is formed, the color filter substrate 22 facing the thin film transistor substrate 21, and the two substrates 21 and 22 to each other, thereby bonding a cell gap. a sealant (not shown) forming a gap, and a liquid crystal layer (not shown) positioned between both substrates 21 and 22 and the sealant (not shown). The liquid crystal display panel 20 forms a screen by adjusting the arrangement of liquid crystal layers (not shown). However, since the liquid crystal display panel 20 is a non-light emitting device, light must be supplied from the backlight unit 30 disposed on the rear surface.

The liquid crystal display panel 20 further includes a polarizing plate (not shown) attached to the front surface of the color filter substrate 22 and the rear surface of the thin film transistor substrate 21 so that light passing through the liquid crystal display panel 20 is cross-polarized. do. The liquid crystal display panel 20 is arranged in a matrix form of the liquid crystal cells forming a pixel unit, and forms an image by adjusting the light transmittance of the liquid crystal cells according to the image signal information transmitted from the driver 25.

A plurality of gate lines (not shown) and a plurality of data lines (not shown) are formed in a matrix form on the thin film transistor substrate 21, and thin film transistors (not shown) are formed at intersections of the gate lines and the data lines; TFT) is formed. The signal voltage transmitted from the driver 25 is applied between the pixel electrode and the common electrode of the color filter substrate 22 to be described later through the thin film transistor, and the liquid crystal between the pixel electrode and the common electrode is aligned in accordance with the signal voltage to provide light. The transmittance is determined.

The color filter substrate 22 includes a color filter and a common electrode in which red, green, and blue or cyan, magenta, and yellow colors are repeatedly formed along the black matrix. The common electrode is made of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO).

One side of the thin film transistor substrate 21 is provided with a driver 25 for applying a drive signal. The driver 25 includes a flexible printed circuit board (FPC. 26), a driving chip (27) mounted on the flexible printed circuit board (26), and a circuit board (PCB) connected to the other side of the flexible printed circuit board (26). 28). The driver 25 illustrated represents a chip on film (COF) method, and other known methods such as a tape carrier package (TCP) and a chip on glass (COG) may be used. In addition, the driver 25 may be formed on the thin film transistor substrate 21 during the wiring formation process.

The backlight unit 30 is a member for supplying light to the liquid crystal display panel 20, and includes a plurality of optical plates 35, a light source unit 40, and a light source unit 40 that cover the entire rear surface of the liquid crystal display panel 20. A supporter 60 fixedly supporting the optical plate 35, a reflector 70 positioned below the light source 40, a side mold 51, a middle mold 53, and a lower chassis 80 accommodating them. do.

The optical plate 35 disposed on the rear surface of the liquid crystal display panel 20 includes a diffusion plate 36, a prism film 37, and a protective film 38.

The diffusion plate 36 is composed of a base plate and a bead-shaped coating layer formed on the base plate. The diffusion plate 36 diffuses the light from the light source unit 40 and supplies it to the liquid crystal display panel 20. Since the diffusion plate 36 is not supported by the light guide plate, unlike the edge type, the diffusion plate 36 may be somewhat thicker for strength. An upper portion of the diffusion plate 36 may be additionally disposed to perform the same function as necessary and have a thin thickness.

The prism film 37 is formed with a triangular prism-shaped prism on the upper surface with a constant arrangement. The prism film 37 collects light diffused from the diffusion plate 36 in a direction perpendicular to the plane of the upper liquid crystal display panel 20. Two prism films 37 are usually used, and the micro prisms formed on each prism film 37 are at an angle. The light passing through the prism film 37 proceeds almost vertically to provide a uniform luminance distribution.

The protection film 38 located at the top protects the prism film 37 that is weak to scratches.

The light source unit 40 includes a lamp 41 which is a plurality of linear light sources arranged in parallel with each other. In the first embodiment of the present invention, the lamp uses a cold cathode fluorescent lamp (CCFL), but is not limited thereto. It is also possible to use other linear light sources such as an external electrode fluorescent lamp (EEFL). The lamp 41 receives power from an inverter (not shown) and is disposed over the entire rear surface of the liquid crystal display panel 20. Both ends of the lamp 41 are electrode portions (not shown) and are accommodated in the lamp holder 42. The lamp holder 42 is located in the side mold 51 through the receiving groove 52 formed in the side mold 51 and is not exposed.

The side molds 51 are provided in pairs on opposite sides of the liquid crystal display panel 20. The side molds 51 surround the lamp holder 42 and support the optical plate 35 as described above. The middle mold 53 supports the liquid crystal display panel 20.

The reflector 70 is positioned between the light source 40 and the bottom chassis 80 to reflect the light of the light source 50 and to supply the light toward the diffuser 36. The reflective plate 70 may be made of polyethylene terephthalate (PET) or polycarbonate (PC). The reflecting plate 70 is attached to the bottom surface of the bottom chassis 80, and the hook insertion hole 81 of the same shape is provided in the same position as the hook insertion hole 81 of the bottom chassis 80. As shown in FIG.

The plurality of supporters 60 are positioned at regular intervals on the reflection plate 70. The supporter 60 includes a main body portion 61 supported by the bottom chassis 80, a support portion 62 for supporting the optical plate 35, a ring-shaped fixing portion 63 for fixing the lamp 41, and a main body portion. Protruding toward the bottom chassis (80) at (63) includes a hook (hook, 64) is inserted into the hook insertion hole 81 of the bottom chassis (80).

The support part 62 protrudes upward from the main body part 61, and supports the center part of the optical plate 35 so that it may not sag under load. The support part 62 is formed between the fixing parts 63 provided in pair.

The fixing part 63 wraps the center part of the lamp 41 to fix the lamp 41, and reduces the load received by the center part of the lamp 41. The fixing part 63 may be provided in two pairs instead of a pair with the support part 62 interposed therebetween.

The hook 64 includes a binding portion 66 having an elastic force.

When the hook 64 is inserted through the hook insertion hole 81 of the reflector plate 70 and the bottom chassis 80 by applying a force as shown in FIGS. 3 and 4, the binding portion 66 of the hook 64 is formed. The hook 64 is attached to the cap portion 82 of the bottom chassis 80 while being pushed into the coupling hole 83 formed on the side surface of the cap portion 82 of the bottom chassis 80. Accordingly, the supporter 60 is fixed to the bottom chassis 80.

The supporter 60 is made of one of polymethyl methacrylate (PMMA), polycarbonate (PC), and polyethylene terephthalate (PET), and is a transparent material that hardly changes the characteristics of light incident by the lamp 41. Prepared. Therefore, most of the light incident from the lamp 41 to the supporter 60 passes through the transparent supporter 60 as it is and is reflected by the reflecting plate 70 positioned on the back of the supporter 60. Will proceed. This is almost the same as the progress of the light that is directly incident on the reflecting plate 70 and the reflection efficiency is almost the same. Therefore, due to a supporter using a white resin having a different material from that of the conventional reflector 70 and having a low reflectance, an arm portion is formed on the screen, thereby reducing the problem of uneven brightness. In addition, even if time passes, there is no fear of discoloration of ultraviolet light like a supporter using a white resin, and thus the LCD may maintain a uniform luminance for a long time. On the other hand, when using the transparent supporter 60, the brightness of the liquid crystal display device may be lowered due to the light leakage phenomenon that the light of the lamp 41 is released to the outside through the coupling hole 83 formed in the cap portion 82. In order to prevent this, the binding portion 66 of the hook 64 is preferably provided separately from the opaque material.

The optical plate 35, the light source unit 40, the reflecting plate 70, and the like are accommodated by the bottom chassis 80. As shown in FIG. 2, a cap 82 is formed on the rear surface of the bottom chassis 80 to block at least a part of the hook 64. 2 is a perspective view showing a part of the back of the bottom chassis 80 for the convenience of understanding. The hook insertion hole 81 is formed in the cap part 82, and the coupling hole 83 is formed in the side surface of the cap part 82 as described above.

The tip portion, which is part of the hook 64, is not exposed to the outside by the cap portion 82 formed on the bottom of the bottom chassis 80. Accordingly, no external impact is directly applied to the hook 64. Therefore, as the conventional hook 64 is exposed to the outside, the shock is transmitted to the supporter 60 by an external impact, and thus the optical plate 30 and the lamp 41 fixed to the supporter 60 are damaged. In the liquid crystal display device according to the first embodiment of the present invention, it can be reduced.

The liquid crystal display panel 20 and the backlight unit 30 are accommodated in the upper chassis 10 and protected. The upper chassis 10 has a display window to expose the effective surface of the liquid crystal display panel 20 to the outside, and is coupled to the bottom chassis 80 of the backlight unit 30.

Hereinafter, a liquid crystal display according to a second exemplary embodiment of the present invention will be described with reference to FIG. 5. FIG. 5 is a cross-sectional view illustrating main parts of the liquid crystal display according to the second exemplary embodiment of the present invention in which the supporter 60 is attached to the bottom chassis 80.

In the liquid crystal display device according to the second embodiment of the present invention, unlike the liquid crystal display device according to the first embodiment of the present invention, the coupling hole 83 is not formed in the cap portion 85 of the bottom chassis 80. Instead, the engaging jaw 84 is formed on the rear surface of the bottom chassis 80 extending in the plate direction. The binding portion 67 of the hook 65 is fixed to the coupling jaw 84 so that the supporter 60 is fixed to the bottom chassis 80. The binding portion 67 may have the same shape as or different from the binding portion 66 of the first embodiment. The liquid crystal display device according to the second embodiment of the present invention can also obtain the same effect as the first embodiment, and there is no coupling hole 83 in the cap portion 85 so that the binding portion 67 can be formed of a transparent material. .

Although some embodiments of the invention have been shown and described, it will be apparent to those skilled in the art that modifications may be made to the embodiment without departing from the spirit or spirit of the invention. . It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents.

As described above, according to the present invention, there is provided a backlight unit and a liquid crystal display including the same, the luminance of which is uniform and protects the supporter from external impact.

Claims (8)

An optical plate; A plurality of lamps positioned on a rear surface of the optical plate; A supporter having a support portion for supporting the optical plate, a fixing portion for fixing the lamp, and a hook formed on a rear surface thereof; And a bottom chassis having a hook insertion hole into which the hook is inserted and a cap portion for blocking at least a portion of the hook. The method of claim 1, The supporter is a backlight unit, characterized in that the transparent material. The method of claim 2, The transparent material is a backlight unit, characterized in that any one of polymethyl methacrylate (PMMA), polycarbonate (PC), polyethylene terephthalate (PET). The method of claim 1, The cap unit further comprises a coupling hole coupled to the hook. The method of claim 1, The cap unit further comprises a coupling jaw coupled to the hook. A liquid crystal display panel; An optical plate positioned on a rear surface of the liquid crystal display panel; A plurality of lamps positioned on a rear surface of the optical plate; A supporter having a support portion for supporting the optical plate, a fixing portion for fixing the lamp, and a hook formed on a rear surface thereof; And a bottom chassis having a hook insertion hole into which the hook is inserted and a cap portion for blocking at least a portion of the hook. The method of claim 6, The cap unit further comprises a coupling hole coupled to the hook. The method of claim 6, The cap unit further comprises a coupling jaw coupled to the hook.

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