TW201403186A - Back light module and display device using same - Google Patents

Abstract

The present invention discloses a back light module and a display device using the same. The back light module includes a light source and a light guide plate. The light guide plate includes a top surface, a bottom surface, and a first incident surface connecting the top surface to the bottom surface. The top surface includes a light emitting area and a light incident area. The light source is placed adjacent to the first incident surface. The light source includes a light emitting surface. The light incident area connects to the first incident surface. The backlight module also includes a light guide bar placed corresponding to the light incident area. The summation of a length of the light guide bar and a length of the light guide plate along a direction at which the light guide bar and the light guide plate are laminated is greater than or the same as a height of the light emitting surface.

Description

Backlight module and liquid crystal display device

The invention relates to a backlight module and a liquid crystal display device.

In recent years, liquid crystal display devices have gradually replaced conventional cathode ray tube display devices because of their advantages of light weight and low radiation, and have become mainstream display products. The liquid crystal display device usually includes a light source, such as a backlight module, to provide the liquid crystal panel with sufficient and uniform planar light.

The backlight module generally includes a light guide plate and a point light source. The light guide plate includes a top surface having a light exiting region, a bottom surface disposed opposite to the top surface, and a plurality of sides connecting the top surface and the bottom surface, wherein one side serves as a light guide plate. Into the glossy surface. The point light source is disposed on a side of the light incident surface of the light guide plate. The light emitted by the point light source enters the light guide plate through the light incident surface, and the backlight module is emitted from the light exiting area of the top surface after the light guide plate propagates.

However, in order to achieve the lightness of the backlight module, the light guide plate occupying the main weight of the backlight module is thinned, and the backlight module using the thin light guide plate is light in weight, and the light-emitting diode as a point light source is thinned. The speed cannot keep up with the thinning speed of the light guide plate, so that the height of the light emitting surface of the light emitting diode is higher than the height of the light incident surface of the light guide plate, that is, the distance between the top surface and the bottom surface of the light guide plate, thereby causing the light emitting diode to emit A part of the light cannot enter the light guide plate, and the utilization of light is not high.

In view of this, it is necessary to provide a backlight module that can improve light utilization efficiency.

In view of this, it is also necessary to provide a liquid crystal display device using the above backlight module.

A backlight module includes a light source and a light guide plate, and the light guide plate includes a top surface, a bottom surface opposite to the top surface, and a first light incident surface on a side of the light guide plate and connected to the top surface and the bottom surface respectively. The top surface includes a light-emitting area, the light source is disposed on a side of the first light-incident surface, the light source has a light-emitting surface, and the top surface further includes a light-in entering area, the light-input area is connected to the first light-incident surface, the backlight module And a light guiding strip, the light guiding strip is disposed on the light guiding plate, and the light guiding strip is disposed corresponding to the light entering area, and the sum of the lengths of the light guiding strip and the light guiding plate in the stacking direction is not less than the light source The light-emitting surface is along a height in a direction in which the light guide strips are stacked with the light guide plate. A part of the light generated by the light source enters the light guide plate through the first light incident surface, and another portion passes through the light guide strip, and is then inserted into the top surface of the light guide plate. The light region enters the light guide plate, and light entering the light guide plate is emitted from the light exit region.

A liquid crystal display device includes a liquid crystal panel and a backlight module adjacent to the liquid crystal panel and providing a light source for the liquid crystal panel. The backlight module includes a light source and a light guide plate, and the light guide plate includes a top surface, a bottom surface opposite to the top surface, and a first light incident surface on a side of the light guide plate and connected to the top surface and the bottom surface, respectively. The light source is disposed on a side of the first light incident surface, the light source has a light emitting surface, and the top surface further includes a light incident region, the light incident region is connected to the first light incident surface, and the backlight module further includes a light guiding strip, the light guiding strip is disposed on the light guiding plate, and the light guiding strip is disposed corresponding to the light entering region, and a sum of lengths of the light guiding strip and the light guiding plate in a stacking direction is not less than the light emitting surface of the light source A portion of the light generated by the light source enters the light guide plate via the first light incident surface along the height of the light guide strip and the light guide plate, and the light incident region on the top surface of the light guide plate passes through the light guide strip after the other portion passes through the light guide strip. The light entering the light guide plate enters the light guide plate and is emitted from the light exiting region.

Compared with the prior art, the light guiding strip of the backlight module and the first light incident surface of the light guide plate jointly receive the light emitted by the light source, and the light guiding strip transmits the light entering the light guiding strip to the light guiding plate, which is equivalent to increasing. The light-in entering area of the light guide plate allows most of the light emitted by the light source to enter the light guide plate and then be converted into a relatively uniform plane light after being converted by the light guide plate, thereby improving the utilization of light.

Please refer to Figure 1 and Figure 2. The liquid crystal display device 2 includes a liquid crystal panel 22 and a backlight module 23. The backlight module 23 is adjacent to the liquid crystal panel 22 and provides backlighting for the liquid crystal panel 22 .

The backlight module 23 includes a plastic frame 25 , an optical film set 24 , a light guide plate 26 , a light source 27 , a reflective structure 28 , and a light guiding strip 29 .

The light guide plate 26 is configured to convert the light emitted by the light source 27 into planar light, and includes a top surface 260, a bottom surface 263 disposed opposite the top surface 260, and a side of the light guide plate 26 and a top surface 260 and a bottom surface, respectively. 263 is connected to the first light incident surface 265. The top surface 260 includes a light incident region 261 and a light exit region 262. The light incident region 261 is adjacent to the first light incident surface 265. In the present embodiment, the light exiting region 262 is coplanar with the light incident region 261. Both the light incident region 261 and the first light incident surface 265 serve as a light incident interface of the light guide plate 26 .

The optical film set 24 is disposed on a side of the top surface 260 having a light exiting region 262. The light guiding strip 29 is disposed on a side of the top surface 260 having the light incident region 261. The light source 27 is disposed on the side of the first light incident surface 265. The reflective structure 28 is disposed on the bottom surface 263 of the light guide plate 26 and surrounds the light source 27.

The light source 27 includes a circuit board 271 and at least two point light sources 272 disposed on the circuit board 271. Each of the point light sources 272 has a light emitting surface 273 through which light generated by the point light source 272 is emitted. The circuit board 271 supplies power to the point source 272.

The reflective structure 28 is configured to reflect the light leakage of the light guide plate 26 and the light source 27 to improve the utilization of light. The reflective structure 28 is a reflective sheet in the embodiment, including a bottom plate 283 and bent from one side of the bottom plate 283 and An extended first bent portion 284. The distance from the junction of the first bent portion 284 to the bottom plate 283 to the free end is greater than the height of the light emitting surface 273 of the light source 27.

The light guide bar 29 includes a light incident surface 291, a light exit surface 292 connected to the light incident surface 291, and a connection surface 293 connecting the light incident surface 291 and the light exit surface 292. The light incident surface 291 is for receiving light emitted by the light source 27, and the light exit surface 292 is for transmitting the light received by the light guide strip 29 to the light guide plate 26. The refractive index of the light guiding strip 29 is greater than the refractive index of the light guide plate 26. In the present embodiment, the light guiding strip 29 is a rectangular parallelepiped, and the light incident surface 291 and the light emitting surface 292 are adjacent side surfaces extending in the longitudinal direction of the rectangular parallelepiped. When the light guiding strip 29 is engaged with the light guiding plate 26, the light guiding strip 29 and the light guiding plate 26 are arranged in a stacking direction, and the length in the Z direction in FIG. 4, that is, the height of the light incident surface 291 and the first entrance. The sum of the heights of the smooth surfaces 265 along the stacking Z direction is not less than the height of the light emitting surface 273 of the light source 27 in the stacking direction of the light guiding strips 29 and the light guiding plate 26.

The frame 25 is a hollow frame. Referring to FIG. 4 together, the frame 25 includes a first side plate 251, a second side plate 252, a third side plate 253, and a fourth side plate 254. The first side plate 251, the second side plate 252, the third side plate 253, and the fourth side plate 254 are connected end to end to form an annular structure. The height of the fourth side plate 254 is smaller than the height of the other three side plates 251, 252, and 253. Therefore, when the plastic frame 25 is engaged with the reflective structure 28, the lower end surfaces of the first and third side plates 251, 253 contact the bottom plate 283, and the lower end surface of the fourth side plate 254 has a certain distance from the bottom plate 283, thereby serving as the light source. The setting of 27 provides a pass channel. The inner side of the first side panel 251, the second side panel 252, the third side panel 253, and the fourth side panel 254 extend toward the center of the plastic frame 25 to extend a receiving plate 255 to divide the receiving space enclosed by the plastic frame 25 into two The first receiving space is for carrying the liquid crystal panel 22, and the second receiving space is for receiving other components of the backlight module 23. The fourth side panel 254 includes a first wall 256 that is sequentially connected, a side wall 257, and the support plate 255. The support plate 255 is adjacent to the center of the plastic frame 25 to cooperate with the support plate 255 on the other side walls to divide the first and second receiving spaces. One end of the side wall 257 is connected to an end of the support plate 255 away from the center of the frame 25, and the opposite end is connected to the first wall 256. The first wall 256, the side wall 257 and the support plate 255 are connected to form a two-stage stepped structure. When the plastic frame 25, the reflective structure 28 and the light source 27 are mated, the distance h between the support plate 255 and the bottom plate 283 is smaller than the distance H between the top end of the light-emitting surface 273 of the point source 272 and the bottom plate 283 at the corresponding position. The width of the free end of the first wall 256 to the side wall 257 is substantially equal to the width of the corresponding position of the light guiding strip 29 and the light source 27. The distance between the first side wall 256 of the side wall 257 and the opposite ends of the support plate 255 is substantially equal to or slightly larger than the corresponding position of the light guiding strip 29. Specifically, the sidewall 257 is located on a side of the first wall 256 adjacent to the lower end surface of the frame 25, and the first wall 256 is parallel to the support plate 255 and perpendicular to the sidewall 257. The first wall 256 and the side wall 257 form a receiving space 250 for accommodating the light guiding strip 29 and the partial light source 27 . The first wall 256 and the inner wall of the side wall 257 facing the receiving space 250 are provided with a reflective material 259 for reflecting the connecting surface 293 of the light guiding strip 29 and the light leakage of the light source 27. The reflective material 259 may also be disposed on the connecting surface 293 of the light guiding strip 29 or may be connected to the first bent portion 284 of the reflective structure 28 and the reflective structure 28 as a unitary structure.

3 and FIG. 4, the bottom surface 263 of the light guide plate 26 is disposed on the bottom plate 283 of the reflective structure 28. The light guide bar 29 is directly disposed on the top of the light guide plate 26 having the light incident region 261. On the face 260, the light exit face 292 is disposed facing the light entrance region 261. The plastic frame 25 is disposed outside the light guide plate 26 and the light guide bar 29 to accommodate both. The light guide bar 29 is received in the accommodating space 250. The lower end faces of the first side plate 251, the second side plate 252, and the third side plate 253 of the plastic frame 25 are disposed on the bottom plate 283. The light guide plate 26 is disposed between the support plate 255 and the bottom plate 283 . The support plate 255 is disposed on the top surface 260 of the light guide plate 26 . In the present embodiment, the light incident surface 291 is flush with the first light incident surface 265. The light source 27 enters the plastic frame 25 through the channel, and the light emitting surface 273 faces the first light incident surface 265 and the light incident surface 291. One end of the first bent portion 284 closes the passage and is attached to the first spread wall 256. The optical film set 24 is disposed on the top surface 260 of the light guide plate 26 having the light exiting region 262.

The liquid crystal panel 22 is disposed on the optical film set 24 and carried by the support plate 255. The height of the lower surface of the liquid crystal panel 22 corresponding to the light exiting region 262 with respect to the bottom surface 263 of the light guide plate 26 is lower than the height of the top end of the light emitting surface 273 of the light source 27 with respect to the bottom surface 263 of the light guide plate 26.

The light emitted by the light source 27 enters the light guide plate 26 and the light guide strip 29 via the first light incident surface 265 and the light incident surface 291, and the light in the light guide strip 29 is finally reflected on the light exit surface via the reflection of the reflective material 259. The light guide bar 29 is emitted from the light incident region 261 , and the light in the light guide plate 26 is reflected by the bottom plate 283 and the light guide plate 26 is emitted through the light exit region 262 . Although the height of the first light incident surface 265 of the light guide plate 26 is smaller than the height of the light emitting surface 273 of the light source 27, the presence of the light guiding strip 29 indirectly increases the ingress of the light guiding strip 29 and the light guiding plate 26. The light-input area of the light guide plate 26 causes most of the light emitted from the light source 27 to enter the light guide plate 26 and is converted by the light guide plate 26 to become a relatively uniform planar light, thereby improving the utilization of light.

Further, the refractive index of the light guiding strip 29 is greater than the refractive index of the light guide plate 26. According to the principle of refraction, the angle of the light that enters the light guide plate 26 after being refracted through the interface between the light exiting surface 292 and the light incident region 261 is diffused.

Please refer to FIG. 5 , which is a cross-sectional view showing the assembled backlight module 33 of the second embodiment of the liquid crystal display device of the present invention. The present embodiment is different from the first embodiment in that the connection surface 393 includes a first connection surface 395 disposed opposite to the light incident surface 391, and a second connection surface 396 disposed opposite to the light exit surface 392 and disposed on the first surface A third connecting surface 397 between the connecting surface 395 and the second connecting surface 396. The light incident surface 391 is parallel to the first connecting surface 395, and the light emitting surface 392 is parallel to the second connecting surface 396. The third connecting surface 397 is an inclined plane connecting the first connecting surface 395 and the second connecting surface 396 which are perpendicular to each other. The first wall 356 and the side wall 357 have a tilting surface 359 that cooperates with the third connecting surface 397 on the inner wall forming the receiving space 350.

Please refer to FIG. 6 , which is a cross-sectional view of the backlight module 43 of the third embodiment of the liquid crystal display device of the present invention after assembly. The third embodiment is different from the first embodiment in that the light incident region 461 of the light guide plate 46 includes a first light incident region 467, a second light incident region 468, and a third light incident region 469. One end of the first light incident region 467 is connected to the light exit region 462, and the opposite end is connected to the second light incident region 468. One end of the second light incident region 468 is connected to the first light incident region 467, and the opposite end is connected to the third light incident region 469. One end of the third light incident region 469 is connected to the second light incident region 468, and the opposite end is connected to the first light incident surface 465. The first light incident region 467 is coplanar with the light exit region 462, and the second light incident region 468 and the third light incident region 469 are recessed toward the inside of the light guide plate 46 to receive a portion of the light guide strip 49. Specifically, the light exiting region 462 and the bottom surface 463 are parallel, and perpendicular to the second light incident region 468 and the first light incident surface 465, and the third light incident region 469 is connected to the second light incident region 468 and the first light incident surface 465. Sloped surface.

The light guiding strip 49 includes a first connecting surface 495 disposed opposite to the light incident surface 491, a second connecting surface 496 connecting the light incident surface 491 and the first connecting surface 495, and opposite to the second connecting surface 496 and the first a third connecting surface 497 disposed adjacent to the connecting surface 495, a fourth connecting surface 498 disposed opposite to the second connecting surface 496 and adjacent to the light incident surface 491, and a connecting fourth connecting surface 498 and a third connecting surface 497 and a fifth connection face 499 between the two. The fourth connection surface 498, the fifth connection surface 499, and the third connection surface 497 form a light exit surface 492. The light exit surface 492 is recessed into the light guide strip 49 to be engaged with the light incident region 461. Specifically, the light incident surface 491, the first connecting surface 495, and the fifth connecting surface 499 are parallel, and the second connecting surface 496 is parallel to the third connecting surface 497 and perpendicular to the light incident surface 491.

When assembled, the third connecting surface 497 is overlapped with the first light incident region 467, the fifth connecting surface 499 is disposed facing the first light incident region 467, and the fourth connecting surface 498 is disposed opposite to the third light incident region 469. The light incident surface 491 is coplanar with the first light incident surface 465 for collectively receiving light emitted by the light source 47.

In summary, the present invention complies with the requirements of the invention patent and submits a patent application according to law. The above description is only the preferred embodiment of the present invention, and equivalent modifications or variations made by those skilled in the art will be included in the following claims.

2. . . Liquid crystal display device

twenty two. . . LCD panel

23, 33, 43. . . Backlight module

25. . . Plastic frame

twenty four. . . Optical film set

26, 46. . . Light guide

27, 47. . . light source

28. . . Reflective structure

29, 49. . . Light guide strip

251. . . First side panel

252. . . Second side panel

253. . . Third side panel

254. . . Fourth side panel

255. . . Support plate

256, 356. . . First wall

257, 357. . . Side wall

359. . . Dip

259. . . Reflective material

260. . . Top surface

263, 463. . . Bottom

265, 465. . . First entrance surface

467. . . First entrance zone

468. . . Second entrance zone

469. . . Third entrance zone

261, 461. . . Light entering area

262, 462. . . Light exit area

271. . . Circuit board

272. . . point Light

273. . . Luminous surface

283. . . Bottom plate

284. . . First bend

291, 391, 491. . . Light incident surface

292, 392, 492. . . Light exit surface

395, 495. . . First connection surface

396, 496. . . Second connection surface

397,497. . . Third connection surface

293, 393. . . Connection surface

250, 350. . . Containing space

498. . . Fourth connection surface

499. . . Fifth connection surface

1 is a perspective exploded view of an embodiment of a liquid crystal display device of the present invention.

2 is a partial enlarged view of a light guide plate, a reflection structure, a light guide bar, and a light source of the liquid crystal display device of FIG. 1.

3 is a schematic view showing the assembly of the backlight module of FIG. 1.

Figure 4 is a schematic cross-sectional view taken along line IV-IV of Figure 3.

Fig. 5 is a cross-sectional view showing the assembly of the backlight module of the second embodiment of the liquid crystal display device of the present invention, wherein the cutting position is the same as the cutting position in Fig. 3 shown in Fig. 4, and the liquid crystal panel is omitted.

6 is a cross-sectional view of the backlight module of the third embodiment of the liquid crystal display device of the present invention after assembly, the cutting position of which is the same as the cutting position in FIG. 3 shown in FIG. 4, and the liquid crystal panel is omitted.

twenty three. . . Backlight module

25. . . Plastic frame

twenty four. . . Optical film set

26. . . Light guide

29. . . Light guide strip

254. . . Fourth side panel

255. . . Support plate

256. . . First wall

257. . . Side wall

259. . . Reflective material

263. . . Bottom

265. . . First entrance surface

272. . . point Light

273. . . Luminous surface

283. . . Bottom plate

284. . . First bend

291. . . Light incident surface

293. . . Connection surface

250. . . Containing space

Claims (11)

A backlight module includes a light source and a light guide plate, and the light guide plate includes a top surface, a bottom surface opposite to the top surface, and a first light incident surface on a side of the light guide plate and connected to the top surface and the bottom surface respectively. The top surface includes a light-emitting area, the light source is disposed on a side of the first light-incident surface, and the light source has a light-emitting surface, wherein the top surface further includes a light-in entering region, and the light-incident region is connected to the first light-incident surface, the backlight The module further includes a light guiding strip disposed on the light guiding plate, and the light guiding strip is disposed corresponding to the light entering region, and the sum of the lengths of the light guiding strip and the light guiding plate in the stacking direction is not less than The light-emitting surface of the light source is along a height of the light guide strip and the light guide plate. The light generated by the light source enters the light guide plate through the first light incident surface, and the other portion passes through the light guide strip and is disposed on the top surface of the light guide plate. The light entering region enters the light guide plate, and light entering the light guide plate is emitted from the light exiting region. The backlight module of claim 1, wherein the light exiting region is coplanar with the light incident region. The backlight module of claim 1, wherein the backlight module further comprises a reflective structure, the reflective structure comprising a bottom plate and a first bent portion bent and extended from the bottom plate to the one side, the bottom plate The first bent portion surrounds the light guide plate and the light source, and a bottom surface of the light guide plate is disposed on the bottom plate. The backlight module of claim 3, wherein the backlight module comprises a plastic frame for accommodating the light source and the light guide plate, wherein the plastic frame is a hollow frame, and the first and second ends are connected in series. a first side panel, a second side panel, a third side panel, and a fourth side panel form an annular structure, the first side panel, the second side panel, and the third side panel The end surface is disposed on the bottom plate, and a lower distance between the lower end surface of the fourth side plate and the bottom plate provides a yielding passage for the setting of the light source. The backlight module of claim 4, wherein the inner side of the first side panel, the second side panel, the third side panel, and the fourth side panel extend together with a support panel to the center of the plastic frame to The accommodating space enclosed by the frame is divided into two parts. The backlight module of claim 5, wherein the fourth side panel comprises a first wall, a side wall and a support plate connected in sequence, the support plate being adjacent to the center of the frame and the other side walls. The support plate cooperates to divide the two receiving spaces, one end of the side wall is connected with one end of the support plate away from the center of the plastic frame, and the opposite end is connected with the first wall, the first wall and the side wall and The support plate is connected to form a two-stage stepped structure, and the distance from the support plate to the bottom plate is smaller than the distance between the top end of the light-emitting surface of the point light source and the bottom plate, and the first wall and the side wall form a receiving space for receiving the space. The light guiding strip and a part of the light source, the first wall and the side wall forming the inner wall of the receiving space are provided with a reflective material. The backlight module of claim 1, wherein the light guide bar has a refractive index greater than a refractive index of the light guide plate. The backlight module of claim 1, wherein the light guiding strip comprises a light incident surface, a light exit surface connected to the light incident surface, a light incident surface of the light guiding strip and a first light incident surface. The light source is disposed opposite to the light source, and the light exiting surface is disposed opposite to the light incident region of the light guide plate to transmit the light in the light guide strip to the light guide plate. The backlight module of claim 1, wherein the light incident region of the light guide plate comprises a first light incident region, a second light incident region and a third light incident region, and one end of the first light incident region Connected to the light exiting region, the opposite end is connected to the second light incident region, one end of the second light incident region is connected to the first light incident region, and the opposite end is connected to the third light incident region, and one end of the third light incident region Connected to the second light incident region, the opposite end is connected to the first light incident surface, the first light incident region and the light exit region are coplanar, and the second light incident region and the third light incident region are concave toward the inside of the light guide plate. The light guide bar includes a first connecting surface disposed opposite to the light incident surface, a second connecting surface connecting the light incident surface and the first connecting surface, and the second connecting surface is opposite to the second connecting surface. a third connecting surface disposed adjacent to the connecting surface, a fourth connecting surface disposed opposite to the second connecting surface and adjacent to the light incident surface, and connecting the fourth connecting surface and the third connecting surface and located therebetween a fifth connecting surface, a fourth connecting surface, a fifth connecting surface and a third connecting surface forming light An exit surface, the light exiting is recessed toward the inside of the light guiding strip to cooperate with the light incident region, the light exiting region and the bottom surface are parallel, and perpendicular to the second light incident region and the first light incident surface, and the third light incident region is The inclined surface of the second light incident region and the first light incident surface is connected, and the light incident surface, the first connecting surface and the fifth connecting surface are parallel, and the second connecting surface is parallel to the third connecting surface and perpendicular to the light incident surface. A liquid crystal display device comprising a liquid crystal panel and a backlight module adjacent to the liquid crystal panel and providing a light source for the liquid crystal panel, wherein the backlight module is according to any one of claims 1 to 9. Backlight module. The liquid crystal display device according to claim 10, wherein a height of a lower surface of the liquid crystal panel corresponding to the light-emitting region with respect to a bottom surface of the light guide plate is lower than a height of a top end of the light-emitting surface of the light source with respect to a bottom surface of the light guide plate.