TWI457662B - Backlight module - Google Patents

Description

Backlight module

The present invention relates to a backlight module, and more particularly to an edge-lit backlight module.

Liquid crystal display (LCD) has high image quality, small size, light weight, low voltage drive, low power consumption and wide application range. It has been widely used in portable TVs, mobile phones, and video recording. In consumer electronics or computer products such as projectors, notebook computers, and desktop monitors, it has become the mainstream of displays.

The traditional liquid crystal display architecture mainly includes an outer frame, a liquid crystal panel, a circuit board and a backlight module. The backlight module includes a plurality of optical sheets, such as a light guide plate, a diffusion sheet and a cymbal sheet, for uniformly distributing the light emitted by the light source on the display panel to provide an image. According to the relative position of the light source and the light-emitting surface, the backlight module can be further divided into a direct-lit backlight module and an edge-lit backlight module. However, although the direct-lit backlight module has better local dimming effect than the edge-lit backlight module, since the direct-lit backlight module increases the overall thickness of the product, it is difficult to apply to thinning and thinning. In the LCD monitor.

It is an object of the present invention to provide an edge-lit backlight module having a local dimming function for making the light output more uniform.

According to an embodiment of the invention, a backlight module includes a first light guide plate, a second light guide plate, a first light source, a second light source, and an optical microstructure. The first light guide plate has a plurality of first light-emitting blocks. The second light guide plate is stacked on the first light guide plate and has at least one second light-emitting block. The first light source is disposed on opposite sides of the first light guide plate, the first light emitting block is adjacent to the first light source, and the second light emitting block is located between the first light emitting blocks. The second light sources are disposed on opposite sides of the second light guide plate. The optical microstructure is disposed on a surface of the second light guide plate, and the optical microstructure comprises a functional microstructure and a light-homing microstructure. The functional microstructure corresponds to the second illumination block setting. The light-homogenizing microstructure is distributed from the second light-emitting block to the second light source, wherein the pattern density of the light-weighting microstructures decreases from the second light-emitting block toward the second light source.

In an embodiment, the light-homing microstructure comprises a plurality of dots, and the spacing between the dots parallel to the direction of the second light source is increased from the second light-emitting block to the second light source.

In one embodiment, the thickness of the first light guide plate and the second light guide plate are uniform.

In an embodiment, the second light guide plate has a light emitting surface, and the optical microstructure is disposed on the bottom surface of the second light guide plate relative to the light emitting surface.

In one embodiment, the second light guide plate has two light incident surfaces and a light exit surface facing the second light source, and the light incident surface is perpendicular to the light exit surface.

In one embodiment, the distribution area of the homogenous microstructure is less than half of the distribution area of the functional microstructure.

In one embodiment, the distribution area of the light-weighting microstructure is one-fifth to one-quarter of the distribution area of the functional microstructure.

In one embodiment, the distribution area of the light-weighting microstructure is one-fifth to one-tenth of the distribution area of the functional microstructure.

In an embodiment, the light of the first light source is mainly emitted from the first light-emitting block.

In an embodiment, the light of the second light source is mainly emitted from the second light-emitting block.

Another aspect of the present invention is a backlight module, including a first light guide plate; a first light source, a second light guide plate, a second light source, a second optical microstructure, a third light guide plate, a third light source, and a third optical microstructure. The first light guide plate has a plurality of first light-emitting blocks. The first light source is disposed on opposite sides of the first light guide plate, and the first light emitting block is disposed adjacent to the first light source. The second light guide plate has a plurality of second light-emitting blocks, which are respectively disposed adjacent to the first light-emitting block. The second light sources are disposed on opposite sides of the second light guide plate. The second optical microstructure is disposed on the second light guide plate, and each of the second optical microstructures includes a second functional microstructure and a second uniform light microstructure. The second functional microstructures respectively correspond to the second lighting block settings. The second light-homing microstructures are respectively distributed from the second light-emitting block to the second light source, wherein the pattern density of the second light-weighting microstructures decreases from the second light-emitting block to the second light source, respectively. The third light guide plate has at least one third light-emitting block adjacent to the second light-emitting block and located between the second light-emitting blocks. The third light sources are respectively disposed on opposite sides of the third light guide plate. The third optical microstructure is disposed on the third light guide plate and includes a third functional microstructure and a third light-homing microstructure. The third functional microstructure corresponds to the third lighting block setting. The third light-homing microstructure is distributed from the third light-emitting block to the third light source, wherein the pattern density of the third light-weighting microstructure is decreased from the third light-emitting block to the third light source.

An edge-lit backlight module having two or more light guide plates can transmit optical micro-structures to have local dimming function, and has local dimming by changing the pattern density of the homogenous microstructure. The function of the side-lit backlight module is more uniform.

The spirit and scope of the present invention will be apparent from the following description of the preferred embodiments of the invention. The spirit and scope of the invention are not departed.

Referring to Figures 1 and 2, there are shown a top view and a cross-sectional view, respectively, of an embodiment of a backlight module of the present invention. The backlight module 200 includes a first light guide plate 210 , a second light guide plate 220 , a plurality of first light sources 230 , and a plurality of second light sources 240 . The second light guide plate 220 is stacked on the first light guide plate 210. The first light sources 230 are respectively located on opposite sides of the first light guide plate 210 , and the second light sources 240 are respectively located on opposite sides of the second light guide plate 220 . The second light source 240 is also superposed on the first light source 230. The first light guide plate 210 has two light incident surfaces 211 and a light exit surface 213 facing the first light source 230 , wherein the light incident surface 211 is perpendicular to the light exit surface 213 . The second light guide plate 220 has two light incident surfaces 221 facing the second light source 240 and a light exit surface 223 , wherein the light incident surface 221 is perpendicular to the light exit surface 223 . In the embodiment, the first light guide plate 210 and the second light guide plate 220 are light guide plates of uniform thickness. In other embodiments, the first light guide plate 210 and the second light guide plate 220 may be wedge-shaped light guide plates, and the first light guide plate 210 and the second light guide plate 220 may be disposed to overlap each other.

The backlight module 200 includes a first optical microstructure 250 disposed on the first light guide 210 and a second optical microstructure 260 disposed on the second light guide 220. The first optical microstructures 250 may be disposed on the bottom surface 215 of the first light guide plate 210 relative to the light exit surface 213 , and the second optical microstructures 260 may be disposed on the bottom surface 225 of the second light guide plate 220 relative to the light exit surface 223 . The second optical microstructure 260 is distributed in the middle portion of the second light guide plate 220. The backlight module 200 can be divided into the first light-emitting block 212 by the design of the first optical microstructure 250 and the second optical microstructure 260. The second illuminating block 222 is configured to implement local dimming in the edge-light type backlight module 200. The specific embodiment of how the present invention implements local dimming and how to reduce the first illuminating will be specifically described below with reference to the drawings. A stitching trace between the block 212 and the second light-emitting block 222.

Referring to FIG. 1 to FIG. 4 together, FIG. 3 and FIG. 4 respectively show bottom views of the first light guide plate 210 and the second light guide plate 220 in FIG. 2 . In FIG. 3, the first light guide plate 210 has a plurality of first light-emitting blocks 212, and the first light-emitting block 212 is adjacent to the first light source 230, and leaves no light in the middle of the first light-emitting blocks 212 on both sides. Block 214. Although the first optical microstructure 250 is distributed on the entire lower surface of the first light guide plate 210, the light emitted by the first light source 230 can be concentrated in the first light-emitting block 212 by the micro-structure design, without Will be emitted from the light exit block 214.

The second light guide plate 220 has at least one second light emitting block 222. The at least one second light emitting block 222 is located between the first light emitting blocks 212, and the second light emitting block 222 is located corresponding to the first light guiding plate. The non-light-emitting block 214 of 210, in other words, the second light-emitting region 222 and the non-light-emitting region 214 of the first light guide plate 210 have overlapping regions in the vertical projection direction. The second optical microstructure 260 is mainly distributed corresponding to the second light-emitting block 222 such that the light emitted by the second light source 240 is mainly emitted from the second light-emitting block 222.

However, in order to make the light emitted by the backlight module 200 more uniform, the second optical microstructure 260 partially overlaps the first light-emitting block 212, and the light of the second light source 240 may be from the periphery of the second light-emitting block 222. Is emitted to alleviate the boundary between the first light-emitting block 212 and the second light-emitting block 222. The second illuminating block 222 is defined as a position on the second light guide plate 220 corresponding to the non-light-emitting block 214 of the first light guide plate 210.

More specifically, the second optical microstructure 260 includes a functional microstructure 262 and a light-homing microstructure 264. The functional microstructure 262 is disposed corresponding to the second light-emitting block 222, and the light-homing microstructure 264 is disposed at the periphery of the functional microstructure 262, that is, from the position of the second light-emitting block 222 to the second light source 240. The direction extends. The homogenous microstructure 264 is coupled to the functional microstructure 262. The position of the homogenous microstructure 264 may partially overlap the position of the first illuminating block 212.

The pattern density of the functional microstructures 262 is uniform such that the light of the second light source 240 is totally reflected by the pattern of the functional microstructures 262 and is emitted from the second light-emitting block 222. The pattern density of the homogenous microstructure 264 is less than the pattern density of the functional microstructure 262, and the pattern density of the homogenous microstructure 264 is further reduced from the functional microstructure 262 toward the second source 240, ie, uniform. The pattern density of the optical microstructures 264 decreases outward from the second illuminating block 222. A small portion of the light emitted by the second light source 240 is also emitted from the corresponding point of the light-homing microstructure 264, so that the connection between the second light-emitting block 222 and the first light-emitting block 212 is smoother, so that the local light is partially smooth. The edge-lit backlight module 200 of the dimming function emits light more uniformly. In this embodiment, the second light source 240 is disposed on opposite sides of the second light guide plate 220, so the light-homing microstructure 264 is opposite to the two sides of the second light-emitting block 222 (with the functional microstructure 262) The second light source 240 extends along the distribution. Since the first light source 230 and the second light source 240 are both disposed on the same side of the second light guide plate 220, the light-homing microstructure 264 is from the opposite sides of the second light-emitting block 222 (with the functional microstructure 262) The first light source 240 extends over the distribution.

The first light-emitting block 212 and the second light-emitting block 222 may be subdivided into a plurality of first sub-light-emitting blocks 216 and a plurality of second sub-light-emitting blocks 224. The first light source 230 located on the two sides of the first light guide plate 210 is also assigned to each of the first sub-light-emitting blocks 216, and the brightness or color temperature of the portion of the first light source 230 corresponding to each of the first sub-light-emitting blocks 216 Etc. can be different to achieve local dimming. The brightness or color temperature of the portion of the second light source 240 corresponding to each of the second sub-light-emitting blocks 224 may be different to achieve local dimming. However, for convenience of explanation, only the first sub-light-emitting block 216 and the second sub-light-emitting block 224 are shown, but the invention is not limited thereto.

Referring to Fig. 5, it is a partially enlarged bottom view of the second light guide plate 220 in Fig. 4. Specifically, the homogenous microstructure 264 includes a plurality of dots that can be formed by printing ink or laser spotting. The spacing between the dots parallel to the direction in which the second light sources 240 are arranged increases from the second lighting block 222 toward the second light source 240. For example, the spacing between the dots is from the second light-emitting block 222 to the second light source 240 in order of spacing d1, d2, d3, d4, and the like. The relationship between the intervals d1, d2, d3, and d4 may be an increase in the equal difference, an increase in the equal ratio, or a random increase. Specifically, the design with increasing pitch variation is suitable for designs with long uniform light distance, and the design with increasing pitch ratio is suitable for designs with short uniform light distance, that is, the area to be set according to the uniform optical microstructure 264 ( Width or length) to determine how it is distributed. The dots of the homogenous microstructure 264 may be randomly distributed as long as the spacing between the dots parallel to the direction of the second light source 240 is increased from the second light-emitting block 222 to the second light source 240. In another embodiment, the light-homing microstructures 264 can also be other surface microstructures that control the path of the light, for example, microstructures that are raised or recessed from the surface of the light guide.

The distribution area of the homogenous microstructure 264 is less than half of the distribution area of the functional microstructure 262 to enhance the effectiveness of substantially uniform light. The distribution area of the homogenous microstructure 264 is one-fifth to one-quarter of the distribution area of the functional microstructure 262. Within this range, the subjective judgment of the human eye is relatively natural and has a good uniform light effect. Since the distribution width of the functional microstructure 262 and the homogenous microstructure 264 on the second light guide plate 220 is the same, in other words, the distribution length y1 of the light-homing microstructure 264 is fifteen of the distribution length y2 of the functional microstructure 262. One to one quarter. However, in order to pursue greater utility of the homogenous microstructure 264, the distribution area of the homogenous microstructure 264 is preferably one-fifth to one-tenth of the distribution area of the functional microstructure 262, ie, uniform. The distribution length y1 of the photomicrostructure 264 is one fifteenth to one tenth of the distribution length y2 of the functional microstructure 262.

The invention can be applied to a backlight module of three or more layers of light guide plates in addition to the edge-light type backlight module of the double-layer light guide plate. In the following embodiments, only the three-layer guide is used. The embodiment of the light panel is described, and the technology can be applied to a backlight module of a plurality of layers of light guide plates.

6 and 7 are respectively a top view and a cross-sectional view showing another embodiment of the backlight module of the present invention. In the backlight module 300, the second light guide plate 320 is stacked on the first light guide plate 310, and the third light guide plate 330 is stacked on the second light guide plate 320. The first light sources 340 are respectively disposed on opposite sides of the first light guide plate 310, the second light sources 350 are respectively disposed on opposite sides of the second light guide plate 320, and the third light sources 360 are respectively disposed on opposite sides of the third light guide plate 330. . In this embodiment, the first light source 340, the second light source 350, and the third light source 360 are disposed on the same side and overlap each other.

The first light guide plate 310 has two first light-emitting blocks 312 disposed adjacent to the first light source 340. The second light guide plate 320 has a plurality of second light-emitting blocks 322 disposed adjacent to the first light-emitting block 312 and located between the first light-emitting blocks 312. The third light guide plate 330 has at least one third light-emitting block 332 disposed thereon, and the third light-emitting block 332 is disposed adjacent to the second light-emitting block 322 and located between the second light-emitting blocks 322. The first light guide plate 310 has a first optical microstructure 390 thereon, the second light guide plate 320 has a second optical microstructure 370 thereon, and the third light guide plate 330 has a third optical microstructure 380, such that the light of the first light source 340 is mainly Light is emitted from the first light-emitting block 312, and the light of the second light source 350 is mainly emitted from the second light-emitting block 322, and the light of the third light source 360 is mainly emitted from the third light-emitting block 332.

In order to make the connection between the first light-emitting block 312, the second light-emitting block 322 and the third light-emitting block 332 smoother, the second optical microstructures 370 distributed on the second light guide plate 320 and the third light guide plate 330 The third optical microstructure 380 can have the same design as the functional microstructures 272 (372, 382) and the light-weight microstructures 274 (374, 384) described above.

Referring to Fig. 8, it is a bottom view of the second light guide plate 320 in Fig. 7. The second light guide plate 320 has two second light-emitting blocks 322. The second optical microstructure 370 includes a second functional microstructure 372 corresponding to the second light-emitting block 322, and is disposed on the periphery of the second light-emitting block 322. a second homogenous microstructure 374 distributed to the second source 350. The second light-homing microstructure 374 can be disposed only on the side of the second light-emitting block 322 facing the adjacent second light source 350, as shown in this embodiment, or, in other embodiments, the second light-homing property. The microstructures 374 can be disposed on opposite sides of the second light-emitting block 322. Likewise, the pattern density of the second light-homing microstructure 374 is decreasing from the second light-emitting block 322 toward the second light source 350. The features of the second uniform light-emitting microstructure 374 can be referred to the description of FIG.

Referring to Fig. 9, it is a bottom view of the third light guide plate 330 in Fig. 8. The third optical microstructure 380 includes a third functional microstructure 382 disposed corresponding to the third light-emitting block 332, and a third uniform light micrometer disposed at the periphery of the third light-emitting block 332 and distributed to the third light source 360. Structure 384. Likewise, the pattern density of the third light-homing microstructure 384 is decreasing from the third light-emitting block 332 toward the third light source 360. The details of the third uniform light-structured microstructure 384 can be referred to the description of FIG.

It will be apparent from the above-described preferred embodiments of the present invention that the application of the present invention has the following advantages. An edge-lit backlight module having two or more light guide plates can transmit optical micro-structures to have local dimming function, and has local dimming by changing the pattern density of the homogenous microstructure. The function of the side-lit backlight module is more uniform.

Although the present invention has been described above in terms of a preferred embodiment, it is not intended to limit the invention, and it is obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. The scope of the invention is defined by the scope of the appended claims.

100. . . Backlight module

200. . . Backlight module

210. . . First light guide

211. . . Glossy surface

212. . . First illuminating block

213. . . Glossy surface

214. . . No light block

215. . . Bottom

216. . . First sub-light block

220. . . Second light guide

221. . . Glossy surface

222. . . Second illuminating block

223. . . Glossy surface

224. . . Second sub-light block

225. . . Bottom

230. . . First light source

240. . . Second light source

250. . . First optical microstructure

260. . . Second optical microstructure

262. . . Functional microstructure

264. . . Uniform microstructure

300. . . Backlight module

310. . . First light guide

312. . . First illuminating block

320. . . Second light guide

322. . . Second illuminating block

330. . . Third light guide

332. . . Third illuminating block

340. . . First light source

350. . . Second light source

360. . . Third light source

370. . . Second optical microstructure

372. . . Second functional microstructure

374. . . Second uniformity microstructure

380. . . Third optical microstructure

382. . . Third functional microstructure

384. . . Third uniformity microstructure

390. . . First optical microstructure

D1, d2, d3, d4. . . spacing

Y1, y2. . . Distribution length

The above and other objects, features, advantages and embodiments of the present invention will become more apparent and understood.

FIG. 1 is a top view of an embodiment of a backlight module of the present invention.

2 is a cross-sectional view showing an embodiment of a backlight module of the present invention.

FIG. 3 is a bottom view of the first light guide plate in FIG. 2.

4 is a bottom view of the second light guide plate in FIG. 2.

Fig. 5 is a partially enlarged bottom view of the second light guide plate in Fig. 4.

FIG. 6 is a top view showing another embodiment of the backlight module of the present invention.

FIG. 7 is a cross-sectional view showing another embodiment of the backlight module of the present invention.

Figure 8 is a bottom view of the second light guide plate in Figure 7.

Figure 9 is a bottom view of the third light guide plate in Figure 8.

220. . . Second light guide

240. . . Second light source

260. . . Second optical microstructure

262. . . Functional microstructure

264. . . Uniform microstructure

D1, d2, d3, d4. . . spacing

Y1, y2. . . Distribution length

Claims (11)

A backlight module includes: a first light guide plate having a plurality of first light-emitting blocks and at least one non-light-emitting block located between the first light-emitting blocks; and a second light guide plate stacked on the first a light guide plate having at least one second light-emitting block; a plurality of first light sources disposed on opposite sides of the first light guide plate, the first light-emitting blocks being adjacent to the first light sources, the second The light emitting block is disposed between the first light emitting blocks; the plurality of second light sources are disposed on opposite sides of the second light guiding plate; and an optical microstructure is disposed on a surface of the second light guiding plate, The optical microstructure includes: a functional microstructure corresponding to the second light-emitting block arrangement, and a light-homing microstructure, distributed from the second light-emitting block to the second light sources, wherein the light-homing property The pattern density of the microstructures decreases from the second light-emitting block toward the second light sources. The backlight module of claim 1, wherein the light-homing microstructure comprises a plurality of dots, and the dots are parallel to a distance between the second light sources from the second light-emitting block to the These second sources are incremented. The backlight module of claim 1, wherein the first The thickness of the light guide plate and the second light guide plate are uniform. The backlight module of claim 1, wherein the second light guide plate has a light emitting surface, and the optical microstructure is disposed on a bottom surface of the second light guide plate opposite to the light emitting surface. The backlight module of claim 1, wherein the second light guide plate has two light incident surfaces and a light exit surface facing the second light sources, and the light incident surfaces are perpendicular to the light exit surface. The backlight module of claim 1, wherein the uniformity microstructure has a distribution area smaller than half of a distribution area of the functional microstructure. The backlight module of claim 6, wherein the uniformity microstructure has a distribution area of one-fifth to one-quarter of the distribution area of the functional microstructure. The backlight module of claim 7, wherein the uniformity microstructure has a distribution area of one-fifth to one-tenth of a distribution area of the functional microstructure. The backlight module of claim 1, wherein the light of the first light sources is mainly emitted from the first light-emitting blocks. The backlight module of claim 1, wherein the light of the second light sources is mainly emitted from the second light-emitting block. A backlight module includes: a first light guide plate having a plurality of first light-emitting blocks and at least one light-emitting block between the first light-emitting blocks; and a plurality of first light sources disposed at the first The first light-emitting blocks are disposed adjacent to the first light-emitting blocks, and the second light-guiding plate has a plurality of second light-emitting blocks disposed adjacent to the first light-emitting blocks respectively; a second light source disposed on opposite sides of the second light guide plate; a plurality of second optical microstructures disposed on the second light guide plate, each of the second optical microstructures comprising: a second functional microstructure And respectively corresponding to the second light-emitting block arrangement, and a second light-homing microstructure, respectively distributed from the second light-emitting blocks to the second light sources, wherein the second light-weighting microstructure The pattern density is decreased from the second light-emitting blocks to the second light sources; a third light guide plate has at least one third light-emitting block adjacent to the second light-emitting blocks and located in the second light-emitting blocks Between blocks; a plurality of third light sources, Respectively disposed on opposite sides of the third light guide plate; and at least one third optical microstructures disposed on the third light guide plate comprising: a third function of the microstructure of a third light-emitting block should be provided And a third light-homing microstructure is distributed from the third light-emitting block to the third light sources, wherein a pattern density of the third light-weighting microstructure is from the third light-emitting block Some of the third sources are decremented.