CN111751921A

CN111751921A - Light guide film, light guide plate, backlight module and display device

Info

Publication number: CN111751921A
Application number: CN201910243507.2A
Authority: CN
Inventors: 戴永辉; 刘凯翔
Original assignee: Ruiyi Guangzhou Optoelectronic Device Co ltd
Current assignee: Ruiyi Guangzhou Optoelectronic Device Co ltd
Priority date: 2019-03-28
Filing date: 2019-03-28
Publication date: 2020-10-09

Abstract

The invention relates to a light guide film, a light guide plate, a backlight module and a display device. The light guide film comprises a substrate and a microstructure layer positioned on the substrate. The substrate has a light incident surface, a light emergent surface, and a bottom surface. The bottom surface is provided with a first reflection area adjacent to the light incident surface and a second reflection area outside the first reflection area. The micro-structure layer is arranged on the bottom surface and comprises a plurality of strip-shaped structures and a plurality of point-shaped structures. The strip-shaped structure is at least positioned in the first reflecting area, the extending direction of the strip-shaped structure is parallel to the light incident surface, and the point-shaped structure is positioned in the second reflecting area. The light guide plate has a structure similar to that of the light guide film. The backlight module and the display device comprise the light guide film or the light guide plate.

Description

Light guide film, light guide plate, backlight module and display device

Technical Field

The present invention relates to a light guide element and applications thereof, and more particularly, to a light guide film, a light guide plate, a backlight module and a display device.

Background

A typical backlight module mainly includes a light source and a light guide plate, and light generated by the light source directly enters the light guide plate. However, when light generated by the light source enters the light guide plate, light with shorter wavelength (such as blue light) is easily absorbed by the light guide plate. Moreover, as the distance of the light propagating on the light guide plate increases, the light with shorter wavelength is emitted from the light-emitting surface of the light guide plate less, which causes the light-emitting surface of the light guide plate to leave the light with longer wavelength (e.g. yellow light) at a portion farther from the light source, thereby exhibiting the color difference of the front-end blue and the rear-end yellow.

Disclosure of Invention

Accordingly, an object of the present invention is to provide a light guiding film that can improve the problem of color difference.

The light guide film comprises a base material and a microstructure layer formed on the base material. The substrate is provided with a light incident surface, a light emergent surface adjacent to the light incident surface, and a bottom surface adjacent to the light incident surface and spaced from the light emergent surface, wherein the bottom surface is provided with a first reflecting region adjacent to the light incident surface and a second reflecting region outside the first reflecting region. The micro-structure layer is arranged on the bottom surface and comprises a plurality of strip-shaped structures and a plurality of point-shaped structures, wherein the strip-shaped structures are at least positioned in the first reflection area, the extending direction of the strip-shaped structures is parallel to the light incident surface, and the point-shaped structures are positioned in the second reflection area.

Another technical means of the present invention is that a portion of the stripe structure is disposed in an area of the second reflective region adjacent to the first reflective region.

In another aspect of the present invention, the distribution region of the stripe structure is adjacent to the light incident surface and the area of the distribution region occupies less than 50% of the area of the bottom surface.

In another aspect of the present invention, the point structures are distributed sparsely near the light incident surface and densely far from the light incident surface.

Another technical means of the present invention is that the dot structures have a smaller size near the light incident surface and a larger size far from the light incident surface.

Another technical means of the present invention is that a distance is formed between adjacent ones of the bar structures, and the distance increases as the distance between the bar structures and the light incident surface increases.

Another objective of the present invention is to provide a backlight module, which includes the light guide film and a light source, wherein the light source emits light toward the light incident surface of the substrate.

Another technical means of the present invention is that the backlight module further includes an optical film set disposed on the light guide film.

Another objective of the present invention is to provide a display device, which includes the backlight module and a display panel disposed on the backlight module.

Another technical means of the present invention is that the display panel has a visible region and a non-visible region, the non-visible region is located at the periphery of the visible region, and the first reflective region of the substrate is located within the projection range of the non-visible region.

Another object of the present invention is to provide a light guide plate capable of improving the color difference problem.

The light guide plate comprises a substrate, a plurality of strip structures and a plurality of point structures. The substrate is provided with a light incident surface, a light emergent surface adjacent to the light incident surface, and a bottom surface adjacent to the light incident surface and spaced from the light emergent surface. The bottom surface is provided with a first reflection area adjacent to the light incident surface and a second reflection area outside the first reflection area. The strip-shaped structure and the point-shaped structure are formed on the bottom surface of the substrate, wherein the strip-shaped structure is at least positioned in the first reflecting area, the extending direction of the strip-shaped structure is parallel to the light incident surface, and the point-shaped structure is positioned in the second reflecting area.

Another technical means of the present invention is that the distribution region of the stripe structure is adjacent to the light incident surface and the area of the distribution region occupies less than 50% of the area of the bottom surface.

Another technical means of the present invention is that the point structures are distributed sparsely near the light incident surface and densely far from the light incident surface.

Another technical means of the present invention is that a distance is formed between adjacent ones of the strip-shaped structures, and the distance increases as the distance between the strip-shaped structure and the light incident surface increases.

Another objective of the present invention is to provide a backlight module, which includes the above-mentioned light guide plate and a light source, wherein the light source emits light toward the light incident surface of the substrate.

Another technical means of the present invention is that the display panel has a visible region and a non-visible region, the non-visible region is located at the periphery of the visible region, and the first reflective region is located within the projection range of the non-visible region.

The invention has the beneficial effects that through the structural design of the light guide film and the light guide plate, yellow light with a larger reflection angle is partially emitted first, so that the blue phenomenon of the light emitting surface at the position adjacent to the light incident surface is relieved, and the light emitting degree of the yellow light at the position of the light emitting surface far away from the light incident surface is reduced, so that the overall light emitting color is balanced and blended, and the problem of chromatic aberration generated by the backlight module and the display device is solved.

Drawings

FIG. 1 is a schematic view illustrating a backlight module according to a first preferred embodiment of the present invention;

FIG. 2 is a schematic view of FIG. 1 at another angle;

FIG. 3 is a graph illustrating the percentage of the distance between the positions of the stripe structures and the dot structures on the light guide film and the light incident surface relative to the length of the light guide plate and the density of the structures;

FIG. 4 is a schematic view illustrating a backlight module according to a second preferred embodiment of the present invention;

FIG. 5 is a diagram illustrating various aspects of dot structures in a second preferred embodiment;

FIG. 6 is a schematic view illustrating a backlight module according to a third preferred embodiment of the present invention;

FIG. 7 is a schematic view illustrating a backlight module according to a fourth preferred embodiment of the present invention;

FIG. 8 is a schematic view illustrating a backlight module according to a fifth preferred embodiment of the present invention; and

FIG. 9 is a schematic diagram illustrating a preferred embodiment of a display device according to the present invention.

Detailed Description

The related technical matters of the present invention will be clearly presented in the following detailed description of the preferred embodiments with reference to the accompanying drawings. Before proceeding with the detailed description, it should be noted that like elements are represented by like numerals.

Referring to fig. 1, a backlight module 100 according to a preferred embodiment of the present invention includes a light guiding film 120 and a light source 180. The light source 180 is mainly used for providing light to the light guiding film 120. The light guide film 120 can refract and reflect the light provided by the light source 180, and improve the optical brightness of the backlight module 100, and can make the color of the light emitted from the backlight module 100 uniform.

The light guiding film 120 includes a substrate 140 and a microstructure layer 160 formed on the substrate 140. The substrate 140 has a light incident surface 141, a light emitting surface 142 adjacent to the light incident surface 141, and a bottom surface 143 adjacent to the light incident surface 141 and spaced from the light emitting surface 142. The bottom surface 143 has a first reflective region 144 adjacent to the light incident surface 141 and a second reflective region 145 outside the first reflective region 144. The microstructure layer 160 is disposed on the bottom surface 143 and includes a plurality of stripe structures 161 and a plurality of dot structures 162. In the embodiment, the bar structures 161 are located in the first reflective region 144, the extending direction of the bar structures 161 is parallel to the light incident surface 141, and the dot structures 162 are located in the second reflective region 145. In addition, in the present embodiment, the bar structures 161 and the dot structures 162 are both protrusion structures, and the bar structures 161 are in a V-cut shape.

In this embodiment, the microstructure layer 160 may be formed by directly coating a UV-curable resin (UV-curable resin) on the bottom surface 143 of the substrate 140, and curing the UV-curable resin by ultraviolet light irradiation. That is, the microstructure layer 160 may be a coating layer with a thickness extremely thin relative to the substrate 140, so as to meet the design requirement of the backlight module 100.

Referring to fig. 2 and 3, in some embodiments, among the dot structures 162 located in the second reflective region 145, each dot structure 162 has the same size. Moreover, the dot structures 162 are distributed sparsely near the light incident surface 141 and densely far from the light incident surface 141. That is, the arrangement density of the dot structures 162 increases as the distance from the light source 180 increases. In addition, in the bar structures 161 located in the first reflective region 144, a distance is formed between adjacent bar structures 161, and the distance increases as the distance between the bar structures 161 and the light incident surface 141 increases.

In the case of using one of the conventional light guiding films (the whole surface is in a V-cut strip structure) instead of the light guiding film 120 of the present embodiment, after the light generated by the light source enters the substrate, the light with a larger angle (for example, yellow light) first emits light, and the light with a smaller angle (for example, blue light) continuously propagates in the substrate until the light exits from a position far away from the light source, which causes the light exiting surface of the substrate to emit light with a front yellow color and a rear blue color. In the case of using another conventional light guiding film (with a dot structure on the whole surface) instead of the light guiding film 120 of the present embodiment, when light generated by the light source enters the substrate and light with a smaller angle (for example, blue light) propagates in the substrate, the light is absorbed more along with the increase of the propagation distance, which causes the light emitting surface of the substrate to have a problem of yellow after being blue. Therefore, in the present embodiment, the microstructure layer 160 is only the V-cut stripe structure 161 close to the light source 180, and the other areas are the dot structures 162, so that yellow light with a larger reflection angle is emitted partially first, thereby alleviating the bluing phenomenon of the light-emitting surface 142 near the light-incident surface 141, improving the light-emitting color of the light-emitting surface 142 of the substrate 140 in the area close to the light source 180 to show slight blue, and simultaneously reducing the yellow light-emitting degree of the light-emitting surface 142 at the position far from the light-incident surface 141, so that the light-emitting surface 142 shows slight yellow in the area far from the light source 180, and greatly reducing the color difference of the light-emitting surface 142, so as to achieve the purpose of balancing and harmonizing the light-emitting color of the entire backlight module 100, thereby solving the problem of. Moreover, since the distance between the bar structures 161 in the first reflective region 144 increases with the distance between the bar structures 161 and the light incident surface 141, that is, the bar structures 161 are more and more sparse as the distance from the light incident surface 141 increases, so that the light emitting degree of the yellow light from the light incident surface 141 brought by the bar structures 161 decreases gradually, and the effect of absorbing the blue light by the material of the substrate 140 decreases gradually toward the center, thereby achieving the effect of good uniformity of light emitting color difference.

In some embodiments, the size of each dot-shaped structure 162 may increase as the distance between the dot-shaped structure 162 and the light source 180 (or the light incident surface 141) increases. In the embodiment shown in fig. 4, the spot-like structures 162 closer to the light source 180 have smaller dimensions, while the spot-like structures 162 further away from the light source 180 have larger dimensions. Therefore, the light can be emitted more uniformly through different configuration modes of the dot structures 162.

Referring to fig. 5, a second preferred embodiment of the backlight module 200 of the present invention is substantially the same as the first preferred embodiment, except that the bar structures 261 have different arrangement designs. As shown in fig. 5, in the present embodiment, a portion of the stripe structure 261 is disposed in the second reflective region 245. That is, the stripe structures 261 are not only distributed in the first reflective region 244, but also disposed in the second reflective region 245 adjacent to the first reflective region 244. Meanwhile, the distribution region of the stripe structure 261 is adjacent to the light incident surface 241 and the area of the distribution region accounts for less than 50% of the area of the bottom surface 243. In addition, the adjacent bar structures 261 have a distance therebetween, and the distance increases as the distance between the bar structures 261 and the light incident surface 241 increases.

Therefore, in the second reflective region 245, there is a region where the stripe structure 261 and the dot structure 262 are simultaneously disposed, and in this region, the stripe structure 261 and the dot structure 262 are overlapped to form a transition region, which makes the effect of compensating for blue/yellow light smoother. In addition, when the dot structures 262 are formed on the bar structures 261, the bright lines formed by the bar structures 261 can be blurred and inconspicuous.

It is further noted that the light guiding film 220 of the present invention has a thickness the same as or smaller than that of the light source 280, so as to reduce the design trend of the backlight module 200. However, in the technical field of lighting fixtures, there is no requirement for extreme thinning of the backlight module 200, and the light guide film 220 may be formed by injection molding or the like with a structure having a larger thickness.

Therefore, as shown in fig. 6, a third preferred embodiment of the backlight module 300 of the present invention is shown, the backlight module 300 of the present embodiment is substantially the same as the aforementioned backlight module, and the difference is that the backlight module 300 of the present embodiment does not use the aforementioned light guiding film, but uses the light guiding plate 320. The light guide plate 320 includes a substrate 340, and a plurality of stripe structures 361 and a plurality of dot structures 362 formed on the substrate 340. Similarly, the substrate 340 has a light incident surface 341, a light emitting surface 342 adjacent to the light incident surface 341, and a bottom surface 343 adjacent to the light incident surface 341 and spaced from the light emitting surface 342. The bottom surface 343 has a first reflective region 344 adjacent to the light incident surface 341 and a second reflective region 345 outside the first reflective region 344. The stripe structures 361 and the dot structures 362 are formed on the bottom surface 343 of the substrate 340, wherein the stripe structures 361 are located in the first reflective regions 344, and the dot structures 362 are located in the second reflective regions 345. In the present embodiment, the arrangement and effects of the stripe structures 361 and the dot structures 362 are the same as those of the embodiment shown in fig. 1, and are not described herein again.

It should be noted that, in the present embodiment, the light guide plate 320 is manufactured by using a mold through an integral injection molding method, so that the substrate 340, the stripe structures 361 and the dot structures 362 are integrally molded, and a layered structure between the substrate 140 and the micro-structure layer 160 is not formed as shown in fig. 1.

Referring to fig. 7, a backlight module 400 according to a fourth preferred embodiment of the present invention is substantially the same as the backlight module 400 according to the third preferred embodiment, except that the strip-shaped structures 461 have different arrangement designs. As shown in fig. 7, in the present embodiment, a portion of the stripe structure 461 is disposed in the second reflective region 445. That is, the stripe structures 461 are not only distributed in the first reflective region 444, but also disposed in the second reflective region 445 adjacent to the first reflective region 444. Meanwhile, the distribution area of the stripe structure 461 is adjacent to the light incident surface 441 and occupies less than 50% of the area of the bottom surface 443. In addition, a distance between adjacent stripe structures 461 is increased along with the increase of the distance between the stripe structures 461 and the light incident surface 441.

Therefore, in the second reflective region 445, there is a region where the stripe structure 461 and the dot structure 462 are simultaneously disposed, and in this region, the stripe structure 461 and the dot structure 462 overlap to form a transition region. In this embodiment, a groove corresponding to the stripe-shaped structure 461 (V-cut) is first formed in the region corresponding to the transition region on the mold, and a circular groove corresponding to the dot-shaped structure 462 (dot) is formed on the groove by laser engraving. Accordingly, the light guide plate 420 formed by injection molding can simultaneously form the dot structures 462 on the stripe structures 461 in the second reflective region 445.

Referring to fig. 8, a fifth preferred embodiment of the backlight module 500 of the present invention is shown, the backlight module 500 of the present embodiment is substantially the same as the first preferred embodiment, except that the present preferred embodiment further includes an optical film set 540 disposed on the light guiding film 520. The optical film set 540 may be selected from a diffusion sheet, a prism sheet or a brightness enhancement film, so that the backlight module 500 has a better optical effect. Of course, the light guide film 520 may be replaced by a light guide plate as shown in fig. 6 or 7, and the disclosure of fig. 8 is not limited thereto.

Referring to fig. 9, a display device 600 according to a preferred embodiment of the invention includes the backlight module 500 shown in fig. 8, and a display panel 620 disposed in the light-emitting direction of the optical film set 540. After entering the light guide film 520, the light generated by the light source 680 is emitted through the light guide film 520 and the optical film set 540 and emitted into the display panel 620, and the same purpose as described above can be achieved. Specifically, the display panel 620 has a visible region 621 and a non-visible region 622, the non-visible region 622 is located at the periphery of the visible region 621, and the first reflective region 544 is located within the projection range of the non-visible region 622. With this design, the bright lines formed by the stripe structures 561 can be prevented from appearing in the visible area 621, which affects the visual effect of the display device 600.

In summary, the bottom surface of the light guide film or the light guide plate is provided with the strip-shaped structures and the point-shaped structures, and the arrangement and density of the strip-shaped structures and the point-shaped structures are adjusted to achieve the purpose of balancing and blending the emergent color of the whole backlight module, thereby solving the problem of chromatic aberration, and thus the purpose of the invention can be achieved.

The above description is only a preferred embodiment of the present invention, and should not be taken as limiting the scope of the invention, which is defined by the appended claims and their equivalents.

[ List of reference numerals ]

100 backlight module

120 light guide film

140 base material

141 incident light surface

142 light emitting surface

143 bottom surface

144 first reflecting area

145 second reflecting region

160 microstructured layer

161 strip structure

162 dot structure

180 light source

200 backlight module

220 light guide film

241 incident light surface

243 bottom surface

244 first reflection area

245 second reflecting region

261 strip structure

262 point structure

280 light source

300 backlight module

320 light guide plate

340 base material

341 light incident surface

342 light-emitting surface

343 bottom surface

344 first reflecting area

345 second reflecting region

361 strip structure

362 point structure

380 light source

400 back light module

420 light guide plate

441 incident plane

443 bottom surface

444 first reflecting region

445 second reflecting region

461 strip structure

462 point structure

480 light source

500 backlight module

520 light directing film

544 first reflection area

545 second reflecting region

540 optical film group

561 strip structure

562 dot structure

580 light source

600 display device

620 display panel

621 visual area

622 non-visible area

680 light source.

Claims

1. A light directing film, comprising:

the substrate is provided with a light incident surface, a light emergent surface adjacent to the light incident surface and a bottom surface adjacent to the light incident surface and spaced from the light emergent surface, and the bottom surface is provided with a first reflecting region adjacent to the light incident surface and a second reflecting region outside the first reflecting region; and

the micro-structure layer is arranged on the bottom surface of the substrate and comprises a plurality of strip-shaped structures and a plurality of point-shaped structures, wherein the strip-shaped structures are at least positioned in the first reflection area, the extending direction of the strip-shaped structures is parallel to the light incident surface, and the point-shaped structures are positioned in the second reflection area.

2. The light directing film of claim 1, wherein a portion of the stripe structures are disposed in a region of the second reflective region adjacent to the first reflective region.

3. The light guide film of claim 1, wherein the distribution regions of the stripe structures are adjacent to the light incident surface and occupy less than 50% of the area of the bottom surface.

4. The light directing film of claim 1, wherein the dot structures are sparsely distributed proximate the input surface and sparsely distributed distal the input surface.

5. The light directing film of claim 1, wherein the dot structures have a smaller dimension adjacent the input surface and a larger dimension away from the input surface.

6. The light guide film according to any one of claims 1 to 5, wherein adjacent strip-shaped structures have a distance therebetween, and the distance increases as the distance between the strip-shaped structures and the light incident surface increases.

7. A backlight module comprising the light guide film according to any one of claims 1 to 6 and a light source, wherein the light source emits light toward the light incident surface of the substrate.

8. The backlight module of claim 7, further comprising an optical film set disposed on the light directing film.

9. A display device comprising the backlight module according to claim 7 or 8, and a display panel disposed on the backlight module.

10. The display device according to claim 9, wherein the display panel has a visible region and a non-visible region, the non-visible region is located at a periphery of the visible region, and the first reflective region of the substrate is located within a projection range of the non-visible region.

11. A light guide plate, comprising:

the light source comprises a substrate, a plurality of strip-shaped structures and a plurality of point-shaped structures, wherein the strip-shaped structures are formed on the bottom surface of the substrate, the strip-shaped structures are at least positioned in the first reflecting area, the extending direction of the strip-shaped structures is parallel to the light incident surface, and the point-shaped structures are positioned in the second reflecting area.

12. The light guide plate according to claim 11, wherein a portion of the stripe structures are disposed in an area of the second reflective region adjacent to the first reflective region.

13. The light guide plate according to claim 11, wherein the distribution regions of the stripe structures are adjacent to the light incident surface and occupy less than 50% of the area of the bottom surface.

14. The light guide plate according to claim 11, wherein the dot structures are sparsely distributed near the light incident surface and sparsely distributed far from the light incident surface.

15. The light guide plate according to claim 11, wherein the dot structures have a smaller size adjacent to the light incident surface and a larger size away from the light incident surface.

16. The light guide plate according to any one of claims 11 to 15, wherein a distance is provided between adjacent strip-shaped structures, and the distance increases as the distance between the strip-shaped structure and the light incident surface increases.

17. A backlight module comprising the light guide plate according to any one of claims 11 to 16 and a light source, wherein the light source emits light toward the light incident surface of the substrate.

18. The backlight module as claimed in claim 17, further comprising an optical film set disposed on the light guide plate.

19. A display device comprising the backlight module according to claim 17 or 18, and a display panel disposed on the backlight module.

20. The display device as claimed in claim 19, wherein the display panel has a visible region and a non-visible region, the non-visible region is located at a periphery of the visible region, and the first reflective region is located within a projection range of the non-visible region.