KR20090122750A - Back light unit - Google Patents

Abstract

PURPOSE: A BLU(Backlight Unit) fixing a liquid crystal panel for fixing the liquid crystal panel in a bending state is provided to smoothly fix the liquid crystal panel in a narrow of the front surface of the top chassis narrows. CONSTITUTION: A bottom chassis(200) comprises an illuminating unit(202). Sidewalls(208) equips a central part caving in to the rear end. A plurality of optical sheets(206) is laminated in the upper end of the sidewall of the bottom chassis. A mold(210) is combined in the bottom chassis installed on the top of the optical sheet. A top chassis(220) comprises the front surface caving in to the rear end the circumference of a liquid crystal panel.

Description

Back light unit

The present invention relates to a backlight unit of a liquid crystal display device, and more particularly, to fix the liquid crystal panel more firmly, thereby preventing the central portion of the liquid crystal panel from protruding or peeling off the TFT substrate and the color filter. The present invention relates to a backlight unit having a new structure to accelerate the bezel.

In general, a liquid crystal display (LCD) is formed by bonding a TFT (Thin Film Transistor) substrate and a color filter to form a liquid crystal panel, and a back light unit (BLU) is installed on the rear side of the liquid crystal panel. do. In such an LCD, when a predetermined voltage is applied to the TFT formed on the TFT substrate, the arrangement of the liquid crystals enclosed in the liquid crystal panel is changed, and the optical characteristics of the light passing through the polarizing plate and the liquid crystal are changed to color through the color filter. It is a display means for outputting the image.

1 shows a laminated structure of a typical LCD. As shown in the drawing, the LCD generally has a structure in which the BLU 10, the TFT substrate 20, and the color filter 30 are stacked. The BLU 10 is a light emitting means for giving visibility to the LCD. The TFT substrate 20 is provided with a TFT, a charge accumulation capacitor, a gate line wiring, a source line wiring, and the like, and is bonded to the color filter 30 to form a liquid crystal panel 40. The color filter 30 imparts a color to the amount of light that changes according to the arrangement change of the liquid crystal, and is formed by depositing an RGB photoresist on the glass substrate, and a polarizing film is attached to the color filter 30. The drive IC for driving the panel is mounted at the edge portion of the TFT substrate 20. The source IC 23 is mounted on the lower edge portion of the TFT substrate 20, and the gate IC 27 or an amorphous silicon gate circuit (ASG) is mounted on the side edge portion of the TFT substrate 20.

Although the BLU is conceptually illustrated in FIG. 1, the BLU actually has the configuration as shown in FIG. 2. Referring to FIG. 2, in the conventional BLU 10, a lighting unit 72 such as a cold cathode fluorescent lamp (CCFL) is installed at the bottom of the lower chassis 70, and an insulating plate 74 is disposed above the lighting unit 72. And the optical sheets 76 are stacked, and an upper chassis 90 for pressing and fixing the circumference of the liquid crystal panel 40 is coupled to the upper portion of the optical sheet 76.

In order to seat the insulating plate 74 and the optical sheet 76 to be spaced apart from the lighting means 72, the first mold 75 is installed inside the lower chassis 70. As shown, the first mold 75 has a seating surface 75a whose bottom is supported by the bottom of the lower chassis 70 and conceals the edge portion of the luminaire 72 along the inner circumference of the lower chassis 70. Has Then, the heat insulating plate 74 and the optical sheet 76 are seated on the seating surface 75a of the first mold 75.

In addition, in order to stably stack the liquid crystal panel 40 at the upper end of the lower chassis 70, the second mold 77 is installed at the upper end of the lower chassis 70. In order to stably mount the liquid crystal panel 40, the second mold 77 also has a seating surface 77a extending inwardly of the lower chassis 70, and the liquid crystal panel 40 on the seating surface 77a. It is mounted seating. Finally, the upper chassis 90 is coupled to the upper portion of the liquid crystal panel 40 to press and fix the circumference of the liquid crystal panel 40. The upper chassis 90 is a configuration forming the appearance of the LCD, also referred to as "bezel".

At this time, it can be seen that the front width of the upper chassis 90 is relatively wide (as indicated by " W1 " in FIG. 2). This is because Vcom lines, seal lines, and the like exist in the outer portion of the liquid crystal panel 40, and these regions are concealed by BM (Black Matrix) or the like to form an image non-display area.

In the conventional general LCD, the bezel width of the LCD front part is not raised as a problem as described above. However, in recent years, attempts have been made to slim the bezel width of the LCD periphery for design reasons or for various other reasons. For example, when a plurality of large-screen LCDs (approximately 40 inches or more) are combined to form a so-called " Tiled " type multi-screen, the bezel width at the outer edge of each LCD serves as a factor of decreasing the continuity of the screen. In order to prevent such a phenomenon, the image non-display area outside the liquid crystal panel 40 should be designed slim, and the width of the front portion of the upper chassis 90 of the BLU 10 should be further reduced.

However, if the width of the front surface of the upper chassis 90 of the BLU 10 is excessively slim, the fixing structure of the liquid crystal panel 40 is weakened, and thus, the center portion of the liquid crystal panel 40 is assembled during the LCD assembly process. There is a problem in that the occurrence rate of defective products, such as being protruded and assembled in a state where the liquid crystal panel 40 is separated from the home position, or the TFT substrate 20 and the color filter 30 of the liquid crystal panel 40 are peeled off. This problem is particularly evident in large screen LCDs larger than 40 inches.

In addition, the structurally weak problem in fixing the liquid crystal panel of the BLU 10 serves as a factor that inhibits the narrow bezel implementation of the LCD.

The present invention has been proposed to solve the above problems, and by structurally improving the lower chassis so that the liquid crystal panel is fixed in a curved state to the rear side, the liquid crystal panel is more firm and positioned even if the width of the front part of the upper chassis is narrow. The backlight unit can be fixed, and the occurrence of defective products such as the central part of the liquid crystal panel protruding to the front or the TFT substrate and the color filter peeled off can be suppressed, and the narrow bezel of the liquid crystal display device can be suppressed. The purpose is to provide.

In the backlight unit of the present invention for achieving the above object, the liquid crystal panel 100 is irradiated with light to give visibility, and at the bottom of the backlight unit of the liquid crystal display device which fixes the liquid crystal panel 100 in position. Illumination means 202 for irradiating light is installed on the liquid crystal panel 100, and sidewalls 208 are installed at the periphery, and at least one pair of sidewalls 208 facing each other among the sidewalls 208 is formed. A lower chassis 200 whose center portion is recessed toward the rear side; A plurality of optical sheets 206 stacked on top of the lower chassis 200; A mold 210 stacked on an upper end of the side wall 208 of the lower chassis 200 and seating the liquid crystal panel 100 on the upper side thereof; And a pair of front parts 220a coupled to an upper portion of the liquid crystal panel 100 to press and fix a circumference of the liquid crystal panel 100, and face each other to correspond to the side wall 208 of the lower chassis 200. And an upper chassis 220 recessed to the rear side.

According to a preferred embodiment of the present invention, the support bar 215 may be installed on the upper end of the lower chassis 200 across the side wall 208 facing the rear side of the liquid crystal panel 100.

In the above embodiment, the light guide plate 252 is further provided on the top of the support bar 215 to cover the top surface of the support bar 215, and the light guide plate 252 is formed in the thickness direction of the lighting means 202. It is more preferable to irradiate light onto the back side of the liquid crystal panel 100 supported by the support bar 215 by receiving the light and emitting light from the upper surface of the support bar 215.

In addition, the light guide plate 252 may be arranged such that both side portions are bent downward to the side of the support bar 215 to direct the lighting means 202.

According to a preferred embodiment of the present invention, the upper chassis 220 may be further provided with a support bar 225 across the front surface portion 220a to support the front surface side of the liquid crystal panel 100.

According to the liquid crystal display device of the present invention, a central portion of a pair of sidewalls facing each other among the sidewalls of the lower chassis is recessed so that the liquid crystal panels stacked thereon are stacked in a bent side, and the upper chassis corresponds to the sidewalls. Since the front part of the recess is formed in the rear side to stably fix the liquid crystal panel, the width of the front part of the upper chassis is narrow, so that the liquid crystal panel can be stably fixed even if the fixing structure of the liquid crystal panel circumference is weak. It is possible to prevent defective parts from protruding in the center part or peeling off the TFT substrate and the color filter. Ultimately, the front width of the upper chassis can be designed to be slim, making the narrow bezel of the LCD easier. To improve the continuity of the screen and improve the readability There is.

In addition, according to the present invention, the support bar provided across the upper end of the lower chassis supports the rear side of the liquid crystal panel, thereby preventing the liquid crystal panel from being excessively recessed inside the lower chassis and fixing the liquid crystal panel more stably. There is.

In addition, in the case of providing the support bar supporting the rear side of the liquid crystal panel as described above, by providing the light guide plate at the upper end of the support bar, there is an effect that can prevent the dark portion generated in the central portion of the liquid crystal panel by the support bar.

In addition, according to the present invention, the support bar provided across the front portion of the upper chassis supports the front side of the liquid crystal panel, thereby preventing the liquid crystal panel from protruding toward the front side more securely, and the liquid crystal panel is more firmly fixed position There is.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings and embodiments.

First of all, the present invention provides a backlight unit which is structurally stabilized by fixing the liquid crystal panel in a curved state to the back side in order to prevent the weakening of the peripheral structure of the liquid crystal panel when the narrow bezel of the LCD is implemented. Referred to). The present invention is to provide a backlight unit suitable for an LCD having a narrow bezel, in particular, an LCD for constituting a multi-screen of a tiled form, but the technical idea of the present invention is a variety of other LCDs (does not have a narrow bezel) May be applied to

In the following description, the structure of the backlight unit according to the present invention will be mainly mentioned, and the "liquid crystal panel" referred to below means a panel in which a TFT substrate and a color filter are bonded, as is commonly known.

3 is an exploded perspective view showing an embodiment of the BLU according to the present invention, Figure 4 is a side view of FIG. Referring to this, the BLU 180 of the present invention is laminated to the lower chassis 200, the luminaire 202 installed at the bottom of the lower chassis 200, and the upper end of the side wall 208 of the lower chassis 200. The optical sheets 206, which are installed on the optical sheet 206, are coupled to the mold 210 for mounting the liquid crystal panel 100, and to the upper portion of the liquid crystal panel 100. It consists of an upper chassis 220 to fix the position.

The lower chassis 200 has sidewalls 208 having a sufficient thickness. Preferably, the side wall 208 of the lower chassis 200 has a thickness corresponding to the width of the image non-display area outside the liquid crystal panel 100. As shown, a plurality of fixing protrusions 231 are installed in the upper end of the side wall 208 of the lower chassis 200. In addition, a plurality of seating portions 241 are formed on the outer surface of the side wall 208 of the lower chassis 200 to which the coupling portion 243 of the mold 210 to be described later is mounted. The seating portion 241 is formed to be concave on the outer surface of the side wall 208, the locking protrusion 242 protruding outward is formed on the seating portion 241.

Preferably, the long sidewalls 208 of the sidewalls 208 of the lower chassis 200 which are opposed to each other are recessed in a central portion thereof in a rear side compared to both ends thereof. More preferably, the upper end of the long side wall 208 is formed in a curved shape with a central portion as shown in the side view of FIG.

The bottom of the lower chassis 200 is provided with commonly known lighting means 202 such as CCFL, LED. If an LED is selected as the luminaire 202, the LEDs are preferably installed over the entire interior of the lower chassis 200. This is to improve light uniformity by irradiating light evenly over the entire active region of the liquid crystal panel 100.

When the CCFL is installed as the luminaire 202, sockets 203 for mounting the CCFL are installed at both ends of the lower chassis 200, as shown. As such, an area in which the socket 203 is installed may generate a dark portion at the outer surface of the liquid crystal panel 100. Therefore, additional lighting means 205 may be installed in the lower chassis 200 to cover an area in which the socket 203 is installed. Since the area in which the additional luminaire 205 is installed is relatively local, the additional luminaire 205 can be installed as an LED. If the CCFL is installed as the additional luminaire 205, the CCFL of the additional luminaire 205 is preferably placed in a direction intersecting with the CCFL of the luminaire 202 as shown in FIG.

The insulating plate 204 and the optical sheet 206 are stacked on the upper end of the side wall 208 of the lower chassis 200. A plurality of through holes 232 are formed at the periphery of the heat insulating plate 204 and the optical sheet 206 to correspond to the fixing protrusion 231 of the upper end of the side wall 208, and thus the heat insulating plate 204 and the optical sheet 206. By inserting the through hole 232 of the fixing protrusion 231, the heat insulating plate 204 and the optical sheet 206 may be fixed in place.

The heat insulating plate 204 is to block the heat generated from the lighting means 202 is transmitted to the liquid crystal panel 100, it is selected as a relatively thick transparent heat insulating material. If a separate heat insulating means is provided or the lighting means 202 is unnecessary, the heat insulating plate 204 may be excluded. The optical sheets 206 include a diffusion sheet, a prism, a brightness enhancement film (BEF), and the like, for diffusing light generated by the lighting means 202.

The mold 210 is configured to fix the optical sheets 206 and to stably mount the liquid crystal panel 100. The mold 210 may be formed of a rubber material or have a rubber attached to an upper surface thereof. The mold 210 also includes a through hole 232 inserted into and coupled to the fixing protrusion 231 of the lower chassis sidewall 208 along the perimeter. In addition, the coupling portion 243 coupled to the seating portion 241 of the lower chassis 200 protrudes downward from the circumference of the mold 210, and the locking portion (241) of the seating portion 241 is attached to the coupling portion 243. The engaging hole 244 is engaged with the 242 is formed. Therefore, when the mold 210 is coupled to the lower chassis 200, the heat insulation plate 204 and the optical sheet 206 are fixedly coupled.

As shown in FIG. 3, the heat insulating plate 204, the optical sheet 206, and the mold 210 have a plate shape or a rectangular frame shape with an open center, and have an elastic force that is easily bent in a plane direction. In addition, the heat insulating plate 204, the optical sheet 206, and the mold 210 are all stacked on the upper end of the side wall 208 of the lower chassis 200. Therefore, as shown in FIG. 3 and FIG. 4, the stacking body is bent in a rear side corresponding to the shape of the side wall 208 of the lower chassis 200.

The upper chassis 220 is coupled to the upper portion of the liquid crystal panel 100, and is configured to press and fix the circumference of the liquid crystal panel 100. Although not shown, the upper chassis 220 is fastened to the side wall 208 of the lower chassis 200 by fastening means such as bolts.

In addition, the front part 220a of the upper chassis 220 has a pair of front parts 220a which are opposed to each other in correspondence with the formation of the side wall 208 of the lower chassis 200 to be recessed to the rear side. Therefore, after the upper chassis 220 is coupled to the upper side of the liquid crystal panel 100, and the upper chassis 220 is fastened to the lower chassis 200, the liquid crystal panel 100 is bent in a state of being bent to the rear side.

In such a structure, even when the width of the front portion 220a of the upper chassis 220 locally presses the edge portion of the liquid crystal panel 100, the center portion of the liquid crystal panel 100 does not protrude toward the front side. Therefore, in implementing the narrow bezel of the LCD, the liquid crystal panel 100 may be installed more stably. In addition, it is possible to prevent the liquid crystal panel 100 from protruding toward the front side during the assembling process of the liquid crystal panel 100 or the separation of the TFT substrate and the color filter due to the projecting force of the liquid crystal panel 100. Therefore, the incidence rate of defective products during the manufacturing process is significantly reduced. In this case, the LCD of the narrow bezel LCD or tiled form of the multi-screen of the present invention is generally used for viewing at a remote location, so that the LCD may be installed even when the liquid crystal panel 100 is slightly bent to the rear side. Visibility will not deteriorate to a degree that is a problem.

5 shows another embodiment of the present invention. Referring to FIG. 5, a support bar 215 is installed at an upper end of the lower chassis 200 to cross the side wall 208 of the long side portion. As shown, the support bar 215 supports the back side of the optical sheet 206 and the liquid crystal panel 100. That is, the support bar 215 supports the rear side of the central portion of the liquid crystal panel 100 so that the liquid crystal panel 100 is more firmly positioned and prevents the liquid crystal panel 100 from being recessed to the rear side.

In this case, the support bar 215 is useful for supporting the liquid crystal panel 100 more firmly, but may act as a factor for generating a dark portion in the central portion of the liquid crystal panel 100. Such dark spots in large screen LCDs are not a big problem, but can sometimes cause some problems (eg, the image looks broken). In order to prevent the dark part generated by the support bar 215 as described above, the light guide plate 252 is preferably installed at the upper end of the support bar 215 as shown in FIG.

The light guide plate 252 is installed to cover the top surface of the support bar 215, and receives the light of the lighting means 202 as a thickness surface and emits light from the top surface of the support bar 215. More preferably, as shown, the light guide plate 252 is disposed such that both side portions are bent downward to the side of the support bar 215 to direct the luminaire 202. The installation structure of the light guide plate 252 may improve the light efficiency of the light guide plate 252. In this way, by providing the light guide plate 252 on the upper end of the support bar 215, it is possible to prevent the dark portion generated in the central portion of the liquid crystal panel 100 by the support bar 215.

6 and 7 show another embodiment of the present invention. Among the components illustrated in FIGS. 6 and 7, the lower chassis 200, the lighting units 202 and 205, the heat insulation plate 204, the optical sheet 206, the mold 210, and the upper chassis 220 may be configured. As mentioned above, duplicate descriptions are omitted.

As shown in FIG. 6, the front part 220a of the upper chassis 220 supports the front side of the liquid crystal panel 100 in response to the support bar 215 installed across the side walls 208 of the lower chassis 200. Support bar 215 may be further installed to cross. As shown in the cross-sectional view of FIG. 7, when the support bar 215 of the lower chassis 200 and the support bar 225 of the upper chassis 220 respectively support the back side and the front side of the liquid crystal panel 100, the liquid crystal panel ( 100) will be more firmly positioned.

6 and 7, when the support bar 225 is installed across the front portion 220a of the upper chassis 220, the liquid crystal panel 100 is supported by the support bar 225. It is unavoidable that the active region of is covered. However, the support bar 225 can firmly support the liquid crystal panel 100 even with a very narrow width of 3 mm or less, and a width of 3 mm or less will not significantly disconnect the image displayed on the screen. This is especially true for large screen LCDs.

On the other hand, the liquid crystal panel 100 may be deformed to correspond to the position where the support bar 225 is installed. For example, a BM may be formed in a cross line crossing the active region of the liquid crystal panel 100 in the longitudinal direction or the transverse direction, and drive ICs such as a gate IC or an ASG may be mounted thereon. In addition, a seal may be applied to the cross line to increase the bonding force between the TFT substrate and the color filter. In this case, the area in which the drive IC or the like is applied or the area in which the seal is applied may be reduced by the outside of the liquid crystal panel 100, which makes the bezel width of the LCD outer portion more slimmer. According to this configuration, although the disadvantage of screen disconnection may occur on a single LCD, when the tiled type multi-screen configuration in which multiple LCDs are combined, the overall screen continuity is greatly improved by minimizing the border width between LCDs. Can be obtained.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes are possible in the technical field of the present invention without departing from the technical spirit of the present invention. It will be clear to those of ordinary knowledge.

1 is an exploded perspective view showing a laminated structure of a general LCD

Figure 2 is a side cross-sectional view showing the structure of a conventional BLU

Figure 3 is an exploded perspective view showing an embodiment of the BLU according to the present invention

4 is a side view of FIG. 3

Figure 5 is a side cross-sectional view showing another embodiment of the present invention

Figure 6 is an exploded perspective view showing another embodiment of the present invention

7 is a side cross-sectional view of FIG. 6

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

100: liquid crystal panel 180: backlight unit

200: lower chassis 202: lighting means

203: socket 204: heat insulation plate

205: lighting means 206: optical sheet

208: sidewall 210: mold

215: support bar 220: upper chassis

225: support bar 231: fixing protrusion

232: through hole 241: seating portion

242: locking portion 243: fastening portion

244: hook hole 252: light guide plate

Claims (5)

In the backlight unit of the liquid crystal display device to give visibility to the liquid crystal panel 100 by giving light, and to fix the position of the liquid crystal panel 100, Illumination means 202 for irradiating light to the liquid crystal panel 100 is installed at a bottom thereof, and sidewalls 208 are installed at the periphery thereof, and at least one pair of sidewalls 208 facing each other among the sidewalls 208. ) The lower chassis 200, the center portion of which is formed recessed to the rear side; A plurality of optical sheets 206 stacked on top of the lower chassis 200; A mold 210 stacked on an upper end of the side wall 208 of the lower chassis 200 and seating the liquid crystal panel 100 on the upper side thereof; And Coupled to the upper portion of the liquid crystal panel 100 to press and fix the circumference of the liquid crystal panel 100, a pair of front portion 220a facing each other corresponding to the side wall 208 of the lower chassis 200 is the rear And an upper chassis 220 recessed to the side. The method of claim 1, Back light unit, characterized in that the support bar 215 is installed across the side wall 208 facing the upper side of the lower chassis 200 to support the rear side of the liquid crystal panel (100). The method of claim 2, A light guide plate 252 is further provided on the top of the support bar 215 to cover the top surface of the support bar 215, and the light guide plate 252 receives light from the lighting means 202 in a thickness plane. Back light unit, characterized in that the surface light emitting from the upper surface of the bar (215). The method of claim 3, wherein The light guide plate 252 is a backlight unit, characterized in that both side portions are arranged to be bent downward to the side of the support bar (215) to direct the lighting means (202). The method according to claim 1 or 2, The upper chassis 220, the back light unit, characterized in that the support bar 225 is installed across the front surface portion 220a to support the front side of the liquid crystal panel (100).

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