TWI439736B - Backlight module and optical film thereof - Google Patents

Description

Backlight module and optical film thereof

The present invention relates to a light source device, and more particularly to a backlight module and an optical film thereof.

The liquid crystal display includes a liquid crystal display panel and a backlight module. Since the liquid crystal display panel itself does not emit light, the display light source required for the liquid crystal display panel needs to be provided by the backlight module.

FIG. 1 is a schematic diagram of a conventional backlight module. Referring to FIG. 1 , the backlight module 100 includes a light source 110 and a light guide plate 120 . The light source 110 is disposed beside the light incident surface 122 of the light guide plate 120 to provide light to the light guide plate 120 , and the light guide plate 120 is used to light the light. It is converted into a surface light source that is emitted from the light exit surface 124. In addition, in order to improve the uniformity of the surface light source, a plurality of optical films may be disposed on the light-emitting surface 124 of the light guide plate 120. The optical films are stacked upward from the light-emitting surface, and sequentially include the lower diffusion sheet 130, the lower jaw 140, and the upper edge. Lens 150 and upper diffuser 160. The lower diffusion sheet 130 first diffuses the surface light source, and then sequentially collects the light from the opposite surface of the upper cymbal sheet 150 by the lower cymbal sheet 140, and then adjusts the light path by the upper diffusion sheet 160 to achieve a uniform surface light source. the goal of.

However, the excessive number of optical films used in the prior art not only causes the thickness of the backlight module 100 to be thicker and heavier, but also takes a lot of time to assemble the optical film, resulting in poor production efficiency of the backlight module 100. In addition, assembly of optical films tends to create assembly tolerances, and excessive optical film can result in accumulation of assembly tolerances, causing significant adverse effects on the quality of the surface light source.

The invention provides an optical film which can be applied to a backlight module to reduce the number of optical films of the backlight module.

The invention further provides a backlight module, which has the advantages of better production efficiency, thinner thickness, lighter weight and better quality of the surface light source.

The invention provides an optical film comprising a substrate, a plurality of first light collecting structures, a plurality of first diffusing structures, a plurality of second light collecting structures, and a plurality of second diffusing structures. The substrate has opposite light-emitting surfaces and light-incident surfaces, and the first light-concentrating structure and the first diffusion structure are alternately arranged on the light-emitting surface in a predetermined direction. The second light collecting structure and the second diffusing structure are alternately arranged on the light incident surface along the predetermined direction.

In an embodiment of the invention, each of the first light collecting structures and each of the second light collecting structures respectively comprise at least one mast, and a long axis of the mast is perpendicular to the predetermined direction.

In an embodiment of the invention, the mast is a triangular prism or a semi-cylindrical.

In an embodiment of the invention, the mast has a recess extending in a direction of the major axis to form two top surfaces on both sides of the recess and a bottom surface in the recess, and the top surface is a convex curved surface, and the bottom surface It is a concave surface.

In an embodiment of the invention, the height difference between the top end of each of the top surfaces and the bottom end of the bottom surface is between 1 micrometer and 30 micrometers, and the distance between the top end and the bottom end in the predetermined direction is greater than 1 micrometer.

In an embodiment of the invention, the height of each of the first light collecting structures and each of the second light collecting structures along the direction of the vertical light incident surface and the light exiting surface is between 1 micrometer and 50 micrometers.

In an embodiment of the invention, each of the first diffusion structures and each of the second diffusion structures are respectively an atomization layer, and the atomization layer has a thickness of 1 micrometer to 30 micrometers.

In an embodiment of the present invention, each of the first diffusion structures and each of the second diffusion structures are respectively an atomization layer, and the first diffusion structure has a haze of 5% to 60%, and the second diffusion structure The haze is between 5% and 90%.

In an embodiment of the invention, each of the first diffusion structures and each of the second diffusion structures are respectively an atomization layer, and a plurality of diffusion particles are disposed in the atomization layer.

In an embodiment of the invention, each of the first diffusion structures and each of the second diffusion structures are respectively an atomization layer, and the atomization layer comprises a first dielectric layer and a second dielectric layer stacked on each other. The refractive index of the first dielectric layer is greater than the refractive index of the second dielectric layer, the contact surface of the first dielectric layer and the second dielectric layer are irregular, and the first dielectric layer of the first diffusion structure is located at the second dielectric layer and the substrate Between the second dielectric layer of the second diffusion structure is located between the first dielectric layer and the substrate.

In an embodiment of the invention, the difference between the refractive index of the first dielectric layer and the refractive index of the second dielectric layer is 0.05.

In an embodiment of the present invention, the area of the bottom surface of each of the first diffusion structures in contact with the light-emitting surface is the same as the area of the bottom surface of each of the first light-concentrating structures that is in contact with the light-emitting surface, and each of the second diffusion structures The area of the bottom surface in contact with the light incident surface is the same as the area of the bottom surface of each of the second light collecting structures that is in contact with the light incident surface.

In an embodiment of the invention, the first light collecting structure corresponds to the second diffusing structure, and the first diffusing structure corresponds to the second light collecting structure. The orthographic projection of the bottom surface of the first light collecting structure on the light incident surface completely overlaps the bottom surface of the second diffusing structure, and the orthographic projection of the bottom surface of the first diffusing structure on the light incident surface completely overlaps the bottom surface of the second light collecting structure.

In an embodiment of the invention, the first light collecting structure corresponds to the second diffusing structure, and the first diffusing structure corresponds to the second light collecting structure.

The invention further provides a backlight module comprising an optical plate, a light source and two sheets of the above optical film. The light source is placed next to the optical plate to provide light to the optical plate. The optical film is stacked in the light exiting direction of the optical plate, and a predetermined direction of one of the optical films is perpendicular to a predetermined direction of the other optical film.

In the backlight module and the optical film of the present invention, since both the light incident surface and the light exit surface of the substrate are provided with a diffusion structure and a light collecting structure, the light diffuses and collects light. In other words, an optical film of the present invention can replace a piece of diffusion sheet and a piece of film used in the prior art. Therefore, the backlight module of the present invention only needs to use two optical films to make the quality of the surface light source meet the demand, so Improve production efficiency.

The above and other objects, features and advantages of the present invention will become more <RTIgt;

2 is a schematic view of a backlight module according to an embodiment of the present invention, and FIG. 3 is a perspective view of two optical films of FIG. Referring to FIG. 2 and FIG. 3 , the backlight module 200 of the embodiment includes an optical plate 210 , a light source 220 , and two optical films 300 a and 300 b . The light source 220 is disposed beside the optical plate 210 to provide light 222 to the optical plate 210, and the optical films 300a, 300b are stacked in the light exiting direction of the optical plate 210. The backlight module 200 of the present embodiment is, for example, a side-lit light-emitting backlight module, so that a light guide plate is used as the optical plate 210. The optical plate 210 can convert the light provided by the light source 220 into a surface light source that is emitted from the light exit surface 212, and the bottom surface 214 of the optical plate 210 can be provided with a reflective sheet 230 to reflect the light 222 entering the optical plate 210 to the light exit surface 212. , thereby improving light utilization. In addition, in the embodiment of the direct type backlight module, a diffusion plate may be selected as the optical plate.

The optical films 300a and 300b include a substrate 310, a plurality of first light collecting structures 320, a plurality of first diffusion structures 330, a plurality of second light collecting structures 340, and a plurality of second diffusion structures 350. The substrate 310 has opposite light incident surfaces 312 and light exiting surfaces 314 . The first light collecting structures 320 and the first diffusing structures 330 are alternately arranged in the predetermined direction on the light emitting surface 314 , and the second light collecting structures 340 and the second diffusing structures 350 . The light incident surface 312 is alternately arranged along the predetermined direction. In the present embodiment, the optical film 300a is different from the predetermined direction of the optical film 300b, wherein the predetermined direction of the optical film 300a is, for example, the X-axis, and the predetermined direction of the optical film 300b is, for example, the Y-axis perpendicular to the X-axis. In other words, the first light collecting structure 320 of the optical film 300a and the first diffusing structure 330 are alternately arranged along the X axis, and the second light collecting structure 340 and the second diffusing structure 350 of the optical film 300a are also alternately arranged along the X axis. The first light collecting structure 320 of the optical film 300b and the first diffusing structure 330 are alternately arranged along the Y axis, and the second light collecting structure 340 and the second diffusing structure 350 of the optical film 300b are also alternately arranged along the Y axis.

In the present embodiment, the first light collecting structure 320 of the optical films 300a, 300b corresponds to the second diffusing structure 350, and the first diffusing structure 330 corresponds to the second light collecting structure 340. In addition, each of the first light collecting structures 320 includes at least one mast 322, and each of the second light collecting structures 340 includes at least one mast 342, and here is an example of two masts, but the present invention The number of masts of each of the first light collecting structures 320 or each of the second light collecting structures 340 is not limited. The masts 322, 342 are, for example, triangular prisms, and the major axes of the masts 322, 342 are, for example, perpendicular to the predetermined direction. That is, the long axes of the masts 322, 342 of the optical film 300a are perpendicular to the X axis, and the long axes of the masts 322, 342 of the optical film 300b are perpendicular to the Y axis. However, the present invention does not limit the long axis of the masts 322, 342 to be perpendicular to the predetermined direction. In addition, the height of each of the first light collecting structures 320 and each of the second light collecting structures 340 along the vertical light incident surface 312 and the light exit surface 314 (ie, the Z axis) is, for example, between 1 micrometer and 50 micrometers, but Not limited to this.

The first diffusion structure 330 and each of the second diffusion structures 350 are respectively an atomization layer, and the first diffusion structure 330 has a haze of, for example, 5% to 60%, and the second diffusion structure 350 The haze is, for example, between 5% and 90%. In an embodiment, the haze of the first diffusion structure 330 is, for example, less than the haze of the second diffusion structure 350. Further, in the atomization layer of the present embodiment, for example, a plurality of diffusion particles 301 are provided to adjust the haze of the atomization layer by the distribution density of the diffusion particles 301. Further, the thickness of the atomized layer is, for example, from 1 μm to 30 μm, but not limited thereto.

In the optical film 300a/300b of the embodiment, the first diffusing structure 330 and the first light collecting structure 320 are disposed on the light emitting surface 314 of the substrate 310, and the second diffusing structure 350 and the second set are disposed on the light incident surface 312. The light structure 340, and the first light collecting structure 320 corresponds to the second diffusing structure 350, the first diffusing structure 330 corresponds to the second light collecting structure 340, so each of the optical films 300a, 300b has both light diffusion and The role of light collection. Specifically, as shown in FIG. 2, the light ray 223 transmitted to the second diffusion structure 350 of the optical film 300a is refracted and scattered by the action of the diffusion particles 301, and a portion of the light 223' passing through the second diffusion structure 350 is Passing through the first light collecting structure 320. When the light ray 223' is emitted from the first light collecting structure 320, the first light collecting structure 320 makes the divergence angle of the light 223' small, thereby achieving the effect of collecting light. In addition, the light ray 224 transmitted to the second light collecting structure 340 of the optical film 300a is first collected by the second light collecting structure 340 and transmitted to the first diffusion structure 330. Next, the diffusion particles 301 in the first diffusion structure 330 scatter the light 224 to achieve the effect of diffusing light. In addition, the mechanism for diffusing and collecting light of the optical film 300b is similar to that of the optical film 300a, and will not be repeated here.

According to the above, the optical films 300a and 300b have the functions of diffusing and collecting light at the same time, so that one piece of the diffusion sheet and one piece of the sheet used in the prior art can be replaced. Specifically, the present embodiment uses the optical film 300a instead of the diffusion sheet 130 and the lower gusset 140 in FIG. 1, and uses the optical film 300b instead of the cymbal 150 and the diffusion sheet 160 in FIG. Therefore, the backlight module 300 of the present embodiment only needs to use two optical films 300a and 300b to achieve the quality of the surface light source of the backlight module 100 of FIG. Compared with the prior art, the backlight module 300 of the embodiment uses a small number of optical films, so that the overall thickness and weight can be reduced. In addition, since the embodiment uses less optical film, the assembly efficiency of the backlight module 300 can be improved to reduce the production cost, and the accumulation of assembly tolerances can be reduced to improve the quality of the surface light source.

In order to achieve better performance of the optical films 300a, 300b, the ratio of the distribution area of each of the first diffusion structures 330 to each of the first light collecting structures 320 on the light-emitting surface 314 may be limited, and each of the second diffusion structures 350 may be limited. The ratio of the distribution area of each of the second light collecting structures 340 on the light incident surface 312. In a preferred embodiment, the first light collecting structure 320 corresponds to the second diffusing structure 350, and the first diffusing structure 330 corresponds to the second light collecting structure 340. The area of the bottom surface 331 of each of the first diffusion structures 330 that is in contact with the light-emitting surface 314 is, for example, the same as the area of the bottom surface 321 of each of the first light-concentrating structures 320 that is in contact with the light-emitting surface 314, and the entrance of each of the second diffusion structures 350 is The area of the bottom surface 351 that the light surface 312 contacts is, for example, the same as the area of the bottom surface 341 of each of the second light collecting structures 340 that is in contact with the light incident surface 312. In other words, the orthographic projection of the bottom surface 321 of the first light collecting structure 320 on the light incident surface 312 completely overlaps the bottom surface 351 of the second diffusion structure 350, and the orthographic projection of the bottom surface 331 of the first diffusion structure 330 on the light incident surface 312 is exactly the same. The bottom surfaces 341 of the second light collecting structure 340 are completely overlapped. In this way, it is ensured that most of the light is collected by the light collecting structure and diffused by the diffusing structure when passing through the optical film 300a or 300b.

The masts of the first light collecting structure 320 and the second light collecting structure 340 may be other shapes in addition to the triangular prisms. Hereinafter, two different embodiments of the masts will be given, but they are not intended to limit the present. The shape of the mast of the invention. In the embodiment shown in Figure 4, the masts 322', 342' are semi-cylindrical. In another embodiment shown in Fig. 5, the first light collecting structure 320' includes, for example, a mast, but the present invention does not limit the number of masts of the first light collecting structure. The mast has a recess 323 extending along the long axis of the mast to form two top surfaces 324 on both sides of the recess 323 and a bottom surface 325 in the recess 323, and the top surface 324 is a convex curved surface, and the bottom surface 325 is a concave curved surface. The height difference D1 between the top end of each top surface 324 and the bottom end of the bottom surface 325 is, for example, between 1 micrometer and 30 micrometers, and the distance D2 between the top end and the bottom end in the predetermined direction is, for example, greater than 1 micrometer. Further, the shape of the second light collecting structure 340' is, for example, the same as that of the first light collecting structure 320'.

It should be noted that although the first light collecting structure and the second light collecting structure are both exemplified by at least one mast, in other embodiments, each mast may also be a plurality of vertebrae arranged along a straight line. Replacement of the shape. Further, although the atomization layer is an effect of atomizing by providing the diffusion particles in the above embodiment, the present invention does not limit the structure of the atomization layer. Taking the optical film shown in FIG. 6 as an example, the first diffusion structure 330' is an atomization layer, and includes a first dielectric layer 332 and a second dielectric layer 334 stacked on each other, wherein the first dielectric layer 332 is located in the second medium. Between layer 334 and substrate 310. The refractive index of the first dielectric layer 332 is greater than the refractive index of the second dielectric layer 334, and the contact surface 333 of the first dielectric layer 332 and the second dielectric layer 334 is irregular. The second diffusion structure 350 is also an atomization layer, and includes a first dielectric layer 352 and a second dielectric layer 354 stacked on each other, wherein the second dielectric layer 354 is located between the first dielectric layer 352 and the substrate 310. The refractive index of the first dielectric layer 352 is greater than the refractive index of the second dielectric layer 354, and the contact surface 353 of the first dielectric layer 352 and the second dielectric layer 354 is irregular.

The irregular contact faces 333, 353 described above are irregular surfaces having high and low undulations, and the light rays may have different angles at the contact faces 333, 353 due to different refractive indices of the interconnected dielectric layers. Refraction and scattering, so that the purpose of diffusing light can be achieved. In this embodiment, the fog of the atomization layer can be adjusted by adjusting the shape of the contact faces 333, 353 and the difference in refractive index between the first dielectric layers 332, 352 and the second dielectric layers 334, 354. degree. In a preferred embodiment, the difference between the refractive indices of the first dielectric layers 332, 352 and the refractive indices of the second dielectric layers 334, 354 is, for example, 0.05.

In summary, in the backlight module and the optical film of the present invention, since both the light incident surface and the light exit surface of the substrate are provided with a diffusion structure and a light collecting structure, the light diffuses and collects light, so One piece of the optical film of the present invention is a piece of diffusion sheet and a piece of ruthenium of the prior art. In this way, the backlight module of the present invention only needs to use two optical films to make the quality of the surface light source meet the requirements, and therefore has the advantages of thin thickness, light weight and good production efficiency, and can also reduce the accumulation of assembly tolerances to improve The quality of the surface light source.

While the present invention has been described in its preferred embodiments, the present invention is not intended to limit the invention, and the present invention may be modified and modified without departing from the spirit and scope of the invention. The scope of protection is subject to the definition of the scope of the patent application.

100, 200. . . Backlight module

110, 220. . . light source

120. . . Light guide

122. . . Glossy surface

124, 212. . . Glossy surface

130. . . Lower diffuser

140. . . Bottom piece

150. . . Captain

160. . . Upper diffuser

210. . . Optical board

214, 321, 331, 341, 351, 325. . . Bottom

222, 223, 224. . . Light

230. . . A reflective sheet

300a, 300b. . . Optical film

301. . . Diffused particle

310. . . Substrate

312. . . Glossy surface

314. . . Glossy surface

320, 320’. . . First light collection structure

322, 322', 342, 342'. . . Pillar

323. . . Depression

324. . . Top surface

330, 330’. . . First diffusion structure

332, 352. . . First dielectric layer

333, 353. . . Contact surfaces

334, 354. . . Second dielectric layer

340, 340’. . . Second light structure

350. . . Second diffusion structure

D1. . . Height difference

D2. . . spacing

FIG. 1 is a schematic diagram of a conventional backlight module.

2 is a schematic diagram of a backlight module according to an embodiment of the invention.

Figure 3 is a perspective view of the two optical films of Figure 2.

4 is a schematic cross-sectional view showing an optical film according to another embodiment of the present invention.

Figure 5 is a cross-sectional view showing an optical film according to another embodiment of the present invention.

Figure 6 is a cross-sectional view showing an optical film according to another embodiment of the present invention.

300a, 300b. . . Optical film

301. . . Diffused particle

310. . . Substrate

312. . . Glossy surface

314. . . Glossy surface

320. . . First light collection structure

322, 342. . . Pillar

330. . . First diffusion structure

340. . . Second light structure

350. . . Second diffusion structure

321, 331, 341, 351. . . Bottom

Claims (15)

An optical film comprising: a substrate having a light emitting surface and a light incident surface; a plurality of first light collecting structures disposed on the light emitting surface; a plurality of first diffusion structures disposed on the light emitting surface, and The first light collecting structures and the first diffusing structures are alternately arranged on the light emitting surface along a predetermined direction; the plurality of second light collecting structures are disposed on the light incident surface; and the plurality of second diffusing structures are disposed on the light emitting surface The light incident surface, and the second light collecting structures and the second diffusion structures are alternately arranged on the light incident surface along the predetermined direction. The optical film of claim 1, wherein each of the first light collecting structures and each of the second light collecting structures respectively comprises at least one mast, and a long axis of the mast is perpendicular to the predetermined direction. The optical film of claim 2, wherein the mast is a triangular prism or a semi-cylindrical. The optical film of claim 2, wherein the mast has a recess extending in a direction of the major axis to form two top surfaces on both sides of the recess and a bottom surface in the recess. And the top surfaces are convex curved surfaces, and the bottom surface is a concave curved surface. The optical film of claim 4, wherein a height difference between a top end of each of the top surfaces and a bottom end of the bottom surface is between 1 micrometer and 30 micrometers, and a distance between the top end and the bottom end in the predetermined direction More than 1 micron. The optical film of claim 1, wherein each of the first light collecting structures and each of the second light collecting structures has a height ranging from 1 micrometer to 50 in a direction perpendicular to the light incident surface and the light emitting surface. Micron. The optical film of claim 1, wherein each of the first diffusion structure and each of the second diffusion structures is an atomization layer, respectively, and the atomization layer has a thickness of from 1 micrometer to 30 micrometers. The optical film of claim 1, wherein each of the first diffusion structure and each of the second diffusion structures is an atomization layer, and the first diffusion structure has a haze of 5% to 60%. The second diffusion structure has a haze of 5% to 90%. The optical film of claim 1, wherein each of the first diffusion structure and each of the second diffusion structures is an atomization layer, and the atomization layer is provided with a plurality of diffusion particles. The optical film of claim 1, wherein each of the first diffusion structure and each of the second diffusion structures is an atomization layer, and the atomization layer comprises a first dielectric layer and a first layer stacked on each other a dielectric layer having a refractive index greater than a refractive index of the second dielectric layer, the contact surface of the first dielectric layer and the second dielectric layer being irregular, the first of the first diffusion structures A dielectric layer is between the second dielectric layer and the substrate, and the second dielectric layer of the second diffusion structure is between the first dielectric layer and the substrate. The optical film of claim 10, wherein a difference between a refractive index of the first dielectric layer and a refractive index of the second dielectric layer is 0.05. The optical film of claim 1, wherein a bottom surface area of each of the first diffusion structures in contact with the light-emitting surface is the same as a bottom surface area of each of the first light-concentrating structures in contact with the light-emitting surface, A bottom surface area of each of the second diffusion structures in contact with the light incident surface is the same as a bottom surface area of each of the second light collecting structures that is in contact with the light incident surface. The optical film of claim 12, wherein the first light collecting structures correspond to the second diffusing structures, and the first diffusing structures correspond to the second light collecting structures, the first An orthographic projection of the bottom surface of the light collecting surface on the light incident surface completely coincides with the bottom surface of the second diffusing structure, and the orthographic projection of the bottom surface of the first diffusing structure on the light incident surface coincides with the second set The bottom surfaces of the light structures completely overlap. The optical film of claim 1, wherein the first light collecting structures correspond to the second diffusing structures, and the first diffusing structures correspond to the second light collecting structures. A backlight module includes: an optical plate; a light source disposed adjacent to the optical plate to provide light to the optical plate; and two optical films stacked in a light emitting direction of the optical plate, each optical film comprising: a substrate having a light emitting surface and a light incident surface; a plurality of first light collecting structures disposed on the light emitting surface; a plurality of first diffusion structures disposed on the light emitting surface, and the first light collecting The structure and the first diffusion structures are alternately arranged on the light-emitting surface along a predetermined direction; the plurality of second light-concentrating structures are disposed on the light-incident surface; and the plurality of second diffusion structures are disposed on the light-incident surface, and The second light collecting structures and the second diffusing structures are alternately arranged in the predetermined direction on the light incident surface; wherein the predetermined direction of one of the optical films is perpendicular to the predetermined one of the optical films direction.