KR100863505B1 - Backlight assembly and liquid crystal display device having the same - Google Patents

Abstract

A backlight assembly and a liquid crystal display having the same are provided to prevent the diffusion plate from being deformed. Fixing grooves are formed on the side of the diffusion plate, fixing protrusions are formed on the inner wall of the storage container for accommodating the diffusion plate, and spaced between the fixing grooves and the fixing protrusions with a first gap, a second gap, and a third gap, The first interval has a sufficient margin to allow expansion of the diffusion plate, and the second and third intervals are provided small to prevent the flow of the diffusion plate. As a result, even when the diffusion plate expands due to absorption of moisture or heat, the phenomenon in which the central portion of the diffusion plate rises can be prevented, and the diffusion plate can be prevented from flowing.

LCD, Diffusion Plate, Direct Method, Mold Frame, Expansion, Moisture, Heat

Description

BACKLIGHT ASSEMBLY AND LIQUID CRYSTAL DISPLAY DEVICE HAVING THE SAME}

1 is a perspective view illustrating a conventional direct backlight method.

2 is a plan view of the backlight assembly.

3 is a perspective cross-sectional view of the II of FIG. 2.

4 is an exploded perspective view of a liquid crystal display device of a direct type according to an embodiment of the present invention.

5 is a perspective view of a backlight assembly according to an embodiment of the present invention.

6 is a plan view of the backlight assembly of FIG. 5.

FIG. 7 is a plan view of sidewalls of the diffusion plate and the storage container of FIG. 6.

8 is a plan view of a backlight assembly according to another embodiment of the present invention.

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

120, 460: diffusion plate 150, 480: storage container

400: liquid crystal display device 420: liquid crystal display panel assembly

461, 462, 463, 464: fixing grooves 481, 482, 483, 484: fixing protrusions

485: step 811, 812, 813, 814: fixing groove

821, 822, 823, 824: fixed protrusion

The present invention relates to a direct type backlight assembly and a liquid crystal display device having the same, and more particularly, to a direct type backlight assembly and a liquid crystal display device having the same to prevent the diffusion plate from being deformed.

1 is a perspective view illustrating a conventional direct backlight method.

Referring to FIG. 1, the conventional direct backlight assembly 100 includes a lamp 130 generating light, a lamp holder 131 supporting a positive electrode portion (not shown) of the lamp 130, and a reflecting plate (not shown). The diffusion sheet 110 and the diffusion plate 120 for diffusing the light generated from the lamp 130, and the storage container 150 for receiving them.

In general, in the direct type backlight assembly 100, a plurality of lamps 130 are provided to provide light so that the liquid crystal display may display an image. Since the light generated from the lamp 130 is emitted radially, a reflecting plate is provided below the lamp 130 to guide the light in a predetermined direction.

Therefore, the light emitted to the lower side of the lamp 130 is changed to the path by the reflecting plate and emitted to the diffusion plate side.

The diffusion sheet 110 and the diffusion plate 120 diffuse the incident light generated from the lamp 110 to make the luminance of the light uniform and emit the light.

The storage container 150 serves to receive the lamp 130, the reflecting plate, the diffusion sheet 110, and the diffusion plate 120.

FIG. 2 is a plan view of the backlight assembly and illustrates a state in which the storage container and the diffuser plate are coupled, and FIG. 3 is a perspective cross-sectional view of the II of FIG. 2, showing a state in which the diffuser plate is deformed.

2 and 3, the storage container 150 has a step 152 formed on an inner wall to accommodate the diffusion plate 120. The step 152 is formed along an inner edge of the storage container 150 and includes a horizontal surface 152a and a vertical surface 152b. Here, the horizontal surface 152a refers to the surface on which the diffusion plate 120 is seated, and the vertical surface 152b is in contact with the horizontal surface 152a and perpendicular to the side of the diffusion plate 120.

The step 152 is provided with a fixing part 151 for preventing the diffusion plate 120 from flowing. That is, the fixing part 151 protrudes inwardly of the storage container 150 from the vertical wall of the corner portion where the side walls of the storage container 150 meet.

Therefore, the fixing part 151 has two protruding surfaces formed at right angles to fix the corner portions where the side surfaces of the diffusion plate 120 meet, and the protruding surfaces are the side surfaces of the corner portions of the diffusion plate 120. Adjacent to the diffusion plate 120 to prevent the flow.

In general, the diffusion plate 120 is made of a thin polymethyl methacrylate (PMMA) plate of about 2mm (PMMA) plate, and serves to diffuse the light generated from the lamp 130.

PMMA is a light and durable plastic that can transmit 93% of visible light and is soluble in polar solvents, but has excellent acid and alkali resistance and can be easily processed into molding, extrusion, film or plate. .

However, PMMA absorbs moisture relatively easily because it has an ester bond in terms of molecular structure and is an amorphous resin.

PMMA has an absorption of 0.3% in an experiment to measure the rate of weight increase after 24 hours immersion in 23 ° C. water.

In addition, since the diffusion plate 120 is provided under the lamp 130 to receive light emitted from the lamp 130, the diffusion plate 120 directly receives heat generated from the lamp 130. The PMMA has a linear expansion coefficient of 6 × 10 ⁻⁵ [mm / ° C.]. As the temperature of the diffusion plate 120 increases, the diffusion plate 120 increases in length, and the area of the diffusion plate 120 is increased. It is increased by the square of the length increment.

Therefore, the diffusion plate 120 is deformed by the absorption and heat of moisture as mentioned above, the deformation is shown as expansion.

That is, when the liquid crystal display is used for a long time, the diffusion plate absorbs the surrounding moisture, and the diffusion plate expands by the heat generated by the lamp.

However, as shown in FIG. 2, the diffusion plate 120 is fixed by the fixing unit 151 of the storage container 150, and the diffusion plate 120 is disposed between the fixing unit 151 and the diffusion plate 120. In order to prevent the flow, the gap W1 formed between the fixing part 151 and the diffusion plate 120 is very small.

Therefore, when the diffusion plate 120 does not expand, the gap W1 may be small enough to prevent the diffusion plate 120 from flowing, but may fix the diffusion plate 120, as shown in FIG. 3. When 120 is inflated by the absorption of water and heat, the corner portion formed by two adjacent sides of the diffusion plate 120 is in contact with the fixing portion 151 by expansion, the expansion is constrained by the fixing portion 151 As a result, the central portion of the diffusion plate 120 is convex.

As a result, the diffusion plate may not function properly, resulting in a problem that causes the LCD to malfunction.

The present invention is to solve such a problem in the prior art, the object of the present invention is to provide a diffusion plate formed with a fixed groove and a fixing projection is provided with a sufficient gap between the storage container for receiving the diffusion plate even if the diffusion plate is expanded It is to provide a backlight assembly that can prevent the central portion of the plate to be convex.

In addition, another object of the present invention is to provide a direct type liquid crystal display device including the backlight assembly.

According to one aspect of the present invention, there is provided a backlight assembly comprising: a diffuser plate having a light source unit for generating light and a first bending preventing unit provided at an upper side of the light source unit to diffuse light and formed on a side surface thereof; And a step for accommodating the light source unit and the diffuser plate, and having a stepped portion on which the diffuser plate is seated, and having a second step for preventing the warp of the diffuser plate, the stepped portion being engaged with the first warp preventing means. Including a container.

According to such a backlight assembly and a liquid crystal display device having the same, a central portion of the diffusion plate can be prevented from convex even if the diffusion plate expands by providing a sufficient gap between the diffusion plate and the storage container.

Hereinafter, a backlight assembly and a liquid crystal display having the same according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

4 is an exploded perspective view of a liquid crystal display device of a direct type according to an embodiment of the present invention.

Referring to FIG. 4, the direct type liquid crystal display device 400 according to the exemplary embodiment of the present invention has a backlight assembly 440 that supplies light to the liquid crystal display panel assembly 420 and the liquid crystal display panel assembly 420. It consists of.

In detail, the liquid crystal display panel assembly 420 includes a color filter substrate 421, a thin film transistor substrate 422, and a liquid crystal (not shown) encapsulated therebetween, and displays an image. The data printed circuit board 424, the data printed circuit board 424, and the thin film transistor substrate 422 are connected to each other to apply a data signal for driving the liquid crystal display panel 423 to a data line of the thin film transistor substrate 422. A tape carrier carrier (Tape Carrier Packager (TCP): 425) and a gate for applying a gate signal for driving the liquid crystal display panel 423 to the gate line of the thin film transistor substrate 422 A printed circuit board 426, a gate printed circuit board 426, and a gate TCP 427 connecting the thin film transistor substrate 422.                     

The backlight assembly 440 may include a lamp 470 for generating light, a lamp holder 471 surrounding an electrode portion (not shown) of the lamp 470, and light emitted radially from the lamp 470. Reflector (not shown) for changing the path to the () side and the diffusion sheet 450 and the diffusion plate 460 to receive the light emitted from the lamp 470 and the reflecting plate and diffuse it to have a uniform brightness distribution And a storage container 480 for storing them.

The middle mold frame 430 for accommodating the liquid crystal display panel 423 is provided above the storage container 480.

The liquid crystal display panel assembly 420 and the backlight assembly 440 are formed by combining a top chassis 410 provided on the upper side of the liquid crystal display panel assembly 420 with a storage container 480 that accommodates the backlight assembly 440. The display device 400 is formed.

5 is a view for explaining the backlight assembly according to an embodiment of the present invention, in particular a perspective view for showing a coupling relationship between the diffusion plate and the housing.

Referring to FIG. 5, the storage container 480 has a step 485 formed along the inner wall of the storage container 480 to accommodate the diffusion plate 460.

The step 485 is composed of a horizontal plane 485a and a vertical plane 485b, where the horizontal plane 485a refers to the surface on which the diffusion plate 460 is seated, and the vertical plane 485b is in contact with the horizontal plane 485a, The surface facing the side of the diffusion plate 460 is referred to.

The step 485 formed along the inner wall of the storage container 480 maintains a constant distance from the side surface of the diffusion plate 460. This is to prevent the central portion of the diffusion plate 460 from being convex by allowing the diffusion plate 460 to expand when the diffusion plate 460 expands due to absorption of moisture or heat.

In addition, the step 485 of the storage container 480 serves to receive and fix the diffusion plate 460, and to prevent the diffusion plate 460 from flowing by an impact or the like. 482, 483, 484).

That is, the storage container 480 has first to fourth sidewalls 480a, 480b, 480c, and 480d, and a first fixing protrusion 481 is formed inside the first sidewall 480a and the second sidewall 480b. The inner side of the second fixing protrusion 481, the third side wall (480c) has a third fixing protrusion (481), and the fourth side wall (480d) has a fourth fixing protrusion (484).

The first to fourth fixing protrusions 481, 482, 483, and 484 protrude from the step 485 formed on the first to fourth sidewalls 480a, 480b, 480c, and 480d of the storage container 480. In addition, the first to fourth fixing protrusions 481, 482, 483, and 484 have a hexahedral shape and are provided at the centers of the first to fourth sidewalls 480a, 480b, 480c, and 480d of the storage container 480, respectively. .

The side of the diffusion plate 460 is fastened to the first to fourth fixing protrusions 481, 482, 483, and 484 provided on the first to fourth sidewalls 480a, 480b, 480c, and 480d of the storage container 480. First to fourth fixing grooves 461, 462, 463, and 464 are formed.

The first to fourth fixing grooves 461, 462, 463, and 464 are formed in the central portion of the side surface of the diffusion plate 460 in response to the first to fourth fixing protrusions 481, 482, 483, and 484.

FIG. 6 is a plan view illustrating the backlight assembly of FIG. 5, in particular, a view illustrating a combined state of a diffusion plate and a storage container, and FIG. 7 is a plan view of the sidewall of the diffusion plate and the storage container of FIG. 6. In particular, it is a figure for showing the coupling relationship of a diffusion plate and a storage container.

6 and 7, the first to fourth fixing protrusions 481, 482, 483, and 484 provided on the first to fourth sidewalls 480a, 480b, 480c, and 480d of the storage container 480 are provided. The first to fourth fixing grooves 461, 462, 463, and 464 formed on side surfaces of the diffusion plate 460 are fastened to each other.

That is, the first fixing protrusion 481 is the first fixing groove 461, the second fixing protrusion 482 is the second fixing groove 462, and the third fixing protrusion 483 is the third fixing groove 463. ) And the fourth fixing protrusion 484 are fastened to the fourth fixing groove 464.

As shown in FIG. 7, the first to fourth fixing grooves 461, 462, 463, and 464 have a rectangular shape, and are parallel to the side surfaces of the diffusion plate 460 and are recessed into the diffusion plate 460. First side surfaces 461b, 462b, 463b, and 464b, and second side surfaces 461a, 462a, 463a, and 464a perpendicular to the side surfaces of the diffusion plate 460 and the first side surfaces 461b, 462b, 463b, and 464b. ) And third side surfaces 461c, 462c, 463c, 464c.

The first to fourth fixing protrusions 481, 482, 483, and 484 correspond to the first to fourth fixing grooves 461, 462, 463, and 464 and the first side surfaces 461b, 462b, 463b, and 464b. Parallel and opposing fourth sides 481b, 482b, 483b, 484b, and fifth and parallel opposing side surfaces 481a, 482a, 483a, 484a, and second sides 461a, 462a, 463a, 464a; And sixth side faces 481c, 482c, 483c, and 484c adjacently opposed to third side faces 461c, 462c, 463c, and 464c.                     

As shown in FIG. 6, the first side surfaces 461b, 462b, 463b, and 464b of the first to fourth fixing grooves 461, 462, 463, and 464 and the first to fourth fixing protrusions 481, 482, The first gap W2 is maintained between the fourth side surfaces 481b, 482b, 483b, and 484b of the 483 and 484.

Second side surfaces 461a, 462a, 463a, 464a of the first to fourth fixing grooves 461, 462, 463, and 464 and fifth side surfaces of the first to fourth fixing protrusions 481, 482, 483, and 484. Third side surfaces 461c, 462c, 463c, and 464c between the first and fourth fixing grooves 461, 462, 463, and 464 and between the first and fourth fixing protrusions 481a, 482a, 483a, and 484a. The second interval W3 and the third interval W4 are also maintained between the sixth side surfaces 481c, 482c, 483c, and 484c of the second and fourth sides 482, 483, and 484.

When the diffusion plate 460 expands due to absorption of moisture and heat, the diffusion plate 460 expands toward the edge of the diffusion plate 460 around the center portion. That is, the diffusion plate 460 expands in the directions D1, D2, D3, and D4 around the center portion.

Therefore, the first to fourth sidewalls 480a, 480b, 480c, and 480d of the storage container 480 accommodating the diffusion plate 460 should maintain a constant distance from the side of the diffusion plate 460. Thus, when the diffusion plate 460 expands, the diffusion plate is allowed to expand by a distance between the first to fourth sidewalls 480a, 480b, 480c, and 480d of the storage container 480 and the side surface of the diffusion plate 460. The central portion of 460 can be prevented from being convex.

In addition, the first spacing W2 between the diffusion plate 460 and the receiving container 480 should be maintained at a sufficient interval to allow the diffusion plate 460 to expand in the directions D1, D2, D3 and D4.                     

On the other hand, the second gap W3 and the third gap W4 should be small enough to fix the diffusion plate 460 in order to prevent the diffusion plate 460 from being flowed by the impact.

In other words, when the diffusion plate 460 expands due to absorption of moisture or heat, the diffusion plate 460 diffuses freely, that is, not constrained in the directions D1, D2, D3, and D4 about the center part. A sufficient first gap W2 may be provided between the plate 460 and the storage container 480 to prevent the central portion of the diffuser plate 460 from convex.

In addition, the gap between the second gap W3 and the third gap W4 should be sufficiently small to prevent the flow of the diffusion plate 460.

Thus, when the diffusion plate 460 moves in the D1 or D3 direction, the gap between the second fixing protrusion 482 and the second fixing groove 462 and the fourth fixing protrusion 484 and the fourth fixing groove 464 are different. The gap is small enough to prevent the diffuser from moving. In addition, when the diffusion plate moves in the direction D2 or D4, the gap between the first fixing protrusion 481 and the first fixing groove 461 and the gap between the third fixing protrusion 483 and the third fixing protrusion 463 are diffuser plates ( The diffuser plate 460 is secured small enough to block movement of the 460.

In the present invention, the fixing grooves 461, 462, 463, 464 and the fixing protrusions 481, 482, 483, and 484 are respectively formed at the central portion of the side surface of the diffusion plate 460 and the inner wall central portion of the storage container 480. do.

This is because when the diffusion plate 460 expands due to absorption of moisture or heat, the diffusion plate 460 expands in the lateral direction of the diffusion plate 460 based on the center portion, and thus, the first to fourth fixing grooves 461 are used. , 462, 463, and 464 and the fixing protrusions 481, 482, 483, and 484 should be provided at the centers of the side and inner walls, so that the diffusion plate 460 is the first to fourth fixing grooves 461 of the diffusion plate 460. , 462, 463, and 464 are expanded in a direction in which the diffusion plate 460 is not damaged.

8 is a plan view of a backlight assembly according to another embodiment of the present invention.

Referring to FIG. 8, the storage container 810 has first to fourth sidewalls 810a, 810b, 810c, and 810d, and includes a first inside the first to fourth sidewalls 810a, 810b, 810c, and 810d. To fourth fixing grooves 811, 812, 813, and 814 are formed.

The diffusion plate 820 has first to fourth fixing protrusions 821, 822, 823, and 824 protruding from the side of the diffusion plate 820 to the outside of the diffusion plate 820. The first to fourth fixing protrusions 821, 822, 823, and 824 are provided at the center portion of the side surface of the diffusion plate 820, respectively, and the first to fourth fixing grooves 811 formed at the center portion of the sidewall of the storage container 810. 812, 813, 814, respectively.

As described in the above-described embodiment of the present invention, when the diffusion plate 820 expands due to absorption of water or heat, the expansion plate 820 is allowed to expand and the diffusion plate 820 is prevented from flowing. For example, the first to fourth fixing grooves 811, 812, 813, 814 of the storage container 810 and the first to fourth fixing protrusions 821, 822, 823, and 824 of the diffusion plate 820 may be provided. There is a first interval W5, a second interval W6, and a third interval W7.

The first gap W5 is provided to have sufficient margin to allow the diffusion plate 820 to expand, and the second gap W6 and the third gap W7 prevent the diffusion plate 820 from flowing. It is provided small in order to.                     

Therefore, when the diffusion plate 820 expands, the expansion is allowed by the first interval W5, and when the diffusion plate 820 flows, the second interval W6 and the third interval W7 are sufficiently small to diffuse. When the plate 820 moves in the direction D1 or D3, the second fixing groove 812, the second fixing protrusion 822, and the fourth fixing groove 814 and the fourth fixing protrusion 824 are diffuser plates 820. When the diffusion plate 820 moves in the direction D2 or D4, the first fixing groove 811, the first fixing protrusion 821, the third fixing groove 813, and the third fixing protrusion 823 are restricted. ) Constrains the movement of the diffuser plate 820.

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

As described above, according to the present invention, a fixing groove is formed in the diffusion plate provided in the backlight assembly, a fixing protrusion for fastening with the fixing groove is formed in the storage container, and the expansion plate and the storage container accommodating the same are expanded. In this regard, the gap between the diffusion plate and the receiving container as well as the space between the fixing groove and the fixing protrusion are sufficiently spaced in the expansion direction of the diffusion plate, so that the center portion of the diffusion plate is raised convexly even if the diffusion plate expands due to absorption of water or heat. The phenomenon can be prevented.

In addition, even though the diffusion plate flows, the diffusion plate can be fixed because there is a small gap between the fixing groove and the fixing projection in the flow direction of the diffusion plate.

Claims (6)

A light source unit generating light with a plurality of lamps arranged in parallel; A diffusion plate provided on an upper side of the light source unit to diffuse the light and have a fixing groove recessed inward from a side surface thereof; And A fixing protrusion for accommodating the light source unit and the diffusion plate, and having a stepped portion on the inner wall to which the diffusion plate is seated, protruding from the stepped portion, and fastened to the fixing groove to fix the diffusion plate and to prevent bending of the diffusion plate. Including a storage container having, The fixing groove is defined by a first side surface formed inwardly of the diffusion plate and parallel to the side surface of the diffusion plate, and second and third side surfaces provided between the side surface of the diffusion plate and the first side surface, Is engaged with the fixing protrusion defined by a fourth side facing the first side, a fifth side facing the second side and a sixth side facing the third side, The gap between the side surface of the diffusion plate and the step and the distance between the first side surface and the fourth side surface to compensate for the expansion of the diffusion plate may be different from the second side surface and the fifth side surface for fixing the diffusion plate. And a gap greater than a gap between the third side and the sixth side. The backlight assembly of claim 1, wherein the fixing groove is formed at the center of the side of the diffusion plate, and the fixing protrusion is formed at the center of the step. delete delete delete delete

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