CN101373234A - Backlight module and its optical film - Google Patents

Abstract

An optical film includes a substrate and at least one triangular pyramid structure. The triangular pyramid-like structure is arranged on one surface of the substrate and is provided with a base, a first surface, a second surface and a third surface which are mutually connected and arranged along the base.

Description

Backlight module and its optical film

technical field

The present invention relates to a backlight module and its optical film, in particular to a backlight module and its optical film capable of enhancing brightness in biaxial directions.

Background technique

With the advent of the digital age, the technology of flat panel display devices has grown rapidly and has become one of the indispensable electronic products. Therefore, the public has higher and higher requirements for the technology and functions of flat panel display devices.

As far as the flat display device is concerned, it mainly includes a flat display panel and a backlight module. Among them, the flat display panel mainly has a color filter substrate, a thin film transistor substrate, and a liquid crystal layer sandwiched between the two substrates; and the backlight module is used as a backlight source, which can evenly distribute light from a light source on the surface of the liquid crystal panel. Traditionally, a cold cathode fluorescent lamp (CCFL) is used as the light source of the backlight module, and the backlight module is divided into a direct type and an edge type according to the arrangement of the light source. Recently, in order to improve the brightness and visual effect of flat-panel display devices, it is necessary to reduce the emission angle of light passing through the brightness enhancement film to within plus or minus 30 to 40 degrees. one of the technologies.

Referring to FIG. 1 , a conventional backlight module 1 includes a light source 11 , at least one diffusion film 14 and a brightness enhancement film 12 . If the backlight module 1 is a side-lit backlight module, the diffusion film 14 and the brightness enhancement film 12 are sequentially disposed on a light guide plate 13 . The light source 11 emits a light L1 and is disposed on one side of the light guide plate 13 . The light L1 is guided by the light guide plate 13 , passes through the diffusion film 14 , and then enters the brightness enhancement film 12 , as shown in FIG. 1 . If the backlight module 1B is a direct-type backlight module, the diffusion film 14 and the brightness enhancement film 12 are sequentially disposed on the light source 11 . The light L1 from the light source 11 directly enters the diffusion film 14 and then enters the brightness enhancement film 12 , as shown in FIG. 2 .

As far as the brightness enhancing film 12 is concerned, the incoming light L1 can be refracted into a small-angle outgoing light, so that the emission angle of most of the light L1 can be reduced to within plus or minus 30 to 40 degrees, so that the viewer can be on the optical axis. There is a stronger visual effect of brightness within plus or minus 30 to 40 degrees. Please refer to FIG. 1 again. According to US Pat. No. 6,091,547, it proposes to have a prism surface structure 121, and the prism surface structure 121 of the brightness enhancement film 12 is arranged in parallel in a single direction V1. However, using the above method can only provide a single-axis direction, such as a horizontal direction or a vertical direction, to provide a brightness enhancement effect. Therefore, if it is desired to achieve the brightness enhancement effect in the biaxial direction, that is, the horizontal direction and the vertical direction, it is necessary to use two brightness enhancement films 12 to overlap each other, and the prism surface structures 121 of the two brightness enhancement films 12 are arranged in the first direction V2 respectively. and the second direction V3 are arranged in parallel, and the first direction V2 and the second direction V3 are perpendicular to each other (as shown in FIG. 2 ).

However, using two brightness enhancing films 12 will not only increase the cost, but also reduce the transmittance.

Therefore, how to provide a backlight module and its optical film that can simultaneously achieve biaxial brightness enhancement, reduce cost, and increase transmittance has become one of the important issues.

Contents of the invention

In view of the above problems, the purpose of the present invention is to provide a backlight module and an optical film thereof that can simultaneously achieve biaxial brightness enhancement effects, reduce costs, and increase transmittance.

Therefore, to achieve the above purpose, an optical film according to the present invention includes a substrate and at least one type of triangular pyramid structure. The triangular pyramid structure is arranged on one side of the substrate, and the triangular pyramid structure has a base, a first surface, a second surface and a third surface, and the first surface, the second surface and the third surface are connected to each other. The connection is arranged along the base, and at least one of the first surface, the second surface and the third surface forms an included angle with the base, and the included angle is less than 90 degrees.

To achieve the above purpose, a backlight module according to the present invention includes a light source and an optical film. The light source emits a light, and the optical film is arranged on an optical path of the light, and has a substrate and at least one type of triangular pyramid structure, the triangular pyramid structure is arranged on one side of the substrate, and the triangular pyramid structure has A base, a first surface, a second surface and a third surface, the first surface, the second surface and the third surface are connected to each other and arranged along the base, and the first surface, the second surface and the third surface At least one side thereof forms an included angle with the base, and the included angle is less than 90 degrees.

Based on the above, the backlight module and its optical film of the present invention are arranged on the optical path of the light emitted by the light source through the optical film, and are arranged on the base through various triangular pyramid structures of the optical film, and At least one of the interconnected first, second and third surfaces of various triangular pyramid structures forms an angle less than 90 degrees with the base. Compared with the traditional technology, the present invention only uses a single piece of optical film, and it has a triangular pyramid structure arranged on the substrate. In this way, not only can the cost be reduced, but also the first surface, the second surface and the third surface of the triangular pyramid-like structure can be used to cooperate, so that the light can reach the biaxial direction when passing through the similar triangular-pyramid structure. The effect of brightness enhancement, thereby avoiding the reduction of light transmittance.

Description of drawings

FIG. 1 is a schematic diagram of a traditional backlight module;

2 is a schematic diagram of another conventional backlight module;

3 is a schematic diagram of a backlight module according to the first embodiment of the present invention;

FIG. 4 is a schematic perspective view according to the first embodiment of the present invention;

5A to 5B are perspective schematic diagrams showing one type of triangular pyramid structure in FIG. 4;

6A to 6C are schematic top views showing different arrangements of optical films according to the first embodiment of the present invention;

FIG. 7A is a schematic cross-sectional view along line AA of FIG. 6A;

Fig. 7B is a schematic cross-sectional view along line BB of Fig. 6B;

8A is a schematic cross-sectional view of another optical film;

8B is a schematic cross-sectional view of yet another optical film;

9A and 9B are schematic diagrams of optical films according to second and third embodiments of the present invention, respectively;

Fig. 10 shows the relationship between the optical axis angle and the brightness of the optical film of the first embodiment of the present invention; and

FIG. 11 shows a schematic diagram of a backlight module according to a second embodiment of the present invention.

Description of component symbols:

1, 2, 3: Backlight module 11, 21, 31: Light source

12: Brightness enhancement film 121: Prismatic surface structure

13, 24: Light guide plate 14: Diffusion film

22, 22A, 22B, 22C, 32: Optical film

221: Substrate

222, 223: Triangular pyramid structure 224: Optical diffusion film

23, 33: The first diffuser 34: The second diffuser

B01: Base D, d: Separation distance

L1, L2, L3: light S01: first side

S02: Second side S03: Third side

S04: The fourth side S11: The first side

S12: Second side S13: Third side

V01: direction V02, V11: first direction

V03, V12: Second direction V13: Third direction

θ: included angle

Detailed ways

A backlight module and its optical film according to a preferred embodiment of the present invention will be described below with reference to related drawings.

Please refer to FIG. 3 , the backlight module 2 of the first embodiment of the present invention includes a light source 21 , an optical film 22 , a first diffusion sheet 23 and a light guide plate 24 . The backlight module 2 of this embodiment can be implemented as a direct-lit backlight module or an edge-lit backlight module. Here, the backlight module 2 is an edge-lit backlight module as an example.

In this embodiment, the first diffusion sheet 23 is disposed on one side of the optical film 22 , and the light guide plate 24 is disposed on the other side of the optical film 22 . The light source 21 is disposed adjacent to the light guide plate 24 , and the light source 21 emits a light L2 toward the light guide plate 24 , and the light L2 passes through the light guide plate 24 and is directed toward the optical film 22 .

Please refer to FIG. 4 to FIG. 5B , which are three-dimensional schematic diagrams of the optical film 22 . In this embodiment, the optical film 22 has a substrate 221 and at least one type of triangular pyramid structure 222 . The material of the optical film 22 can be a polyethylene terephthalate (polyethylene terephthalate, PET), a polycarbonate (polycarbonate, PC) or a polymethyl methacrylate (PMMA), certainly can be A translucent material.

Various triangular pyramid structures 222 are disposed on one side of the substrate 221 and have a base B01 , a first surface S01 , a second surface S02 and a third surface S03 . The base B01 has a first side S11, a second side S12 and a third side S13 connected to each other (as shown in FIG. 5A and FIG. 5B ), and the first surface S01, the second surface S02 and the third surface The S03 is respectively disposed along the first side S11 , the second side S12 and the third side S13 of the base B01 .

That is, the first surface S01 , the second surface S02 and the third surface S03 are respectively connected to the first side S11 , the second side S12 and the third side S13 . At least one of the first surface S01, the second surface S02 and the third surface S03 forms an included angle θ with the base B01, and the included angle θ is less than 90 degrees, for example, the first surface S01, the second surface S02 and the second surface S02 The three surfaces S03 and the base B01 form an included angle θ of less than 90 degrees (as shown in FIG. 4 and FIG. 5A ), or the third surface S03 and the base B01 form an included angle θ of less than 90 degrees, and the first surface S01 And the second surface S02 forms an included angle θ of 90 degrees with the base B01 (as shown in FIG. 5B ).

In this embodiment, the shape of the base B01 is a triangle in practice, and the lengths of the first side S11, the second side S12 and the third side S13 of the base B01 are about 10 μm to 100 μm, and the first side S11 1. The lengths of the second side S12 and the third side S13 are substantially the same, for example, the base B01 is an equilateral triangle; or, the first side S11 , the second side S12 and the third side S13 are substantially different. Certainly, the first side S11 , the second side S12 , and the third side S13 of the base B01 can be substantially the same length, for example, the base B01 is an equilateral triangle. In addition, the shapes of the first surface S01 , the second surface S02 and the third surface S03 of the quasi-triangular pyramid structure 222 are respectively a type of triangle, a right triangle or an equilateral triangle. The pyramid height h of the triangular pyramid structure 222 is the same as or different from the lengths of the first side S11 , the second side S12 and the third side S13 .

In addition, please refer to FIG. 5B again, the triangular pyramid structure 223 of this embodiment also has a fourth surface S04, which is opposite to the first surface S01, the second surface S02 and the third surface S03 relative to the base B01. connected, and the fourth surface S04 is implemented as a plane, an inclined surface or an arc surface. Here, the fourth surface S04 is taken as a plane as an example, and the fourth surface S04 is used to protect and prevent superimposition on the optical Components on the film 22 such as a flat display panel (not shown) etc. are scratched.

Please refer to FIG. 6A to FIG. 6C , which are schematic top views of the optical films 22A, 22B, and 22C. The arrangement of the quasi-triangular pyramid structures 222 is not limited. In practice, they are arranged in a regular arrangement (as shown in FIG. 6A and FIG. 6B ) or in an irregular arrangement, that is, a random arrangement (as shown in FIG. 6C ). When the triangular pyramid-like structure 222 is arranged regularly, there is the following arrangement. One kind of triangular-pyramid-like structure 222 of the optical film 22A can be arranged alternately along a first direction V11 and a second direction V12; One kind of triangular pyramid structure 222 of the optical film 22B is arranged in a staggered manner along a third direction V13. Certainly, the quasi-triangular pyramid structure 222 can be further arranged with a distance d, D between each other (as shown in FIG. 6A and FIG. 6B ), or can be connected to each other (not shown).

In addition, please refer to FIG. 7A to FIG. 8B , which are cross-sectional views of the optical films 22A and 22B in FIG. 6A and FIG. and shown in FIG. 7B ) or recessed (as shown in FIGS. 8A and 8B ) on the surface of the substrate 221 .

The base plate 221 and various types of triangular pyramid structures 222 can be integrally formed or bonded. Here, the substrate 221 and various triangular pyramid structures 222 are integrally formed as an example, and the manufacturing method of the triangular pyramid structure 222 is not limited, and soft pressing, hot pressing, hot rolling, ultraviolet curing, The substrate 221 is formed on the substrate 221 by methods such as micro-electro-mechanical technology, electroforming, molding process, or micro-manufacturing process.

In addition, please refer to FIG. 9A and FIG. 9B, the optical film 22 also has an optical diffusion film 224, which is arranged on the other side of the substrate 221 relative to the triangular pyramid structure 222, and the material of the optical diffusion film 224 is implemented. It includes a mixture of light-transmitting resin and particles (as shown in FIG. 9A ), and of course it can be a light-transmitting material with a surface microstructure (as shown in FIG. 9B ). In this embodiment, the surface of the substrate 221 on which the triangular pyramid-like structure 222 is disposed is implemented as a light-emitting surface, and the other surface opposite to the surface of the substrate 221 is a light-incoming surface.

Please refer to FIG. 10 , when the light enters the above-mentioned optical film 22 and its triangular pyramid structure 222, the light is refracted into a small angle and exits, and the viewing angle and luminance gain from the A direction and the B direction are obtained after calculation by the simulation software. The results show that the viewing angle is within plus or minus 30 to 40 degrees, and the gain value of the luminance is greater than 1, so the brightness of the light can be greatly improved.

The backlight module 2 of this embodiment not only needs to cooperate with the first surface S01, the second surface S02 and the third surface S03 of the triangular pyramid-like structure 222 of the single optical film 22, but the light L2 can pass through the The quasi-triangular pyramid structure 222 achieves the effect of enhancing the brightness in the biaxial direction, that is, the vertical direction and the horizontal direction, which can further reduce the cost and avoid the reduction of the light transmittance.

Please refer to FIG. 11 , the backlight module 3 of the second embodiment of the present invention includes a light source 31 , an optical film 32 and a first diffusion sheet 33 . The light source 31, the optical film 32 and the first diffuser 33 have the same structure and function as the light source 21, the optical film 22 and the first diffuser 23 of the above-mentioned first embodiment (as shown in FIG. 3 ), so they will not be repeated here. repeat. The difference between the backlight module 3 of this embodiment and the backlight module 2 of the first embodiment (as shown in FIG. 3 ) is that the former backlight module 3 further includes a second diffusion sheet 34 .

In addition, the first diffuser 33 is arranged on one side of the optical film 32, the second diffuser 34 is arranged on the other side of the optical film 32, and the light source emits a light, and is arranged on one side of the second diffuser 34 opposite to the optical film. side, so the backlight module 3 of this embodiment is a direct-down type backlight module.

To sum up, in the backlight module and its optical film of the present invention, the optical film is arranged on the light path of the light emitted by the light source, and is arranged on the base by various triangular pyramid structures of the optical film, and each At least one of the interconnected first, second and third surfaces of the triangular-pyramid-column-like structure forms an angle less than 90 degrees with the base. Compared with the traditional technology, the present invention only uses a single piece of optical film, and it has a triangular pyramid structure arranged on the substrate. This method can not only reduce the cost, but also through the cooperation of the first surface, the second surface and the third surface of the triangular pyramid structure, the light can achieve biaxial brightness when passing through the triangular pyramid structure. Enhanced effect, thereby avoiding the reduction of light transmittance.

The above descriptions are illustrative only, not restrictive. Any equivalent modification or change without departing from the spirit and scope of the present invention shall be included in the present invention.

Claims (23)

1. An optical film, comprising: a substrate; and At least one type of triangular pyramid structure is arranged on one side of the substrate, the triangular pyramid structure has a base, a first surface, a second surface and a third surface, the first surface, the second surface And the third surface is interconnected and disposed along the base. 2. The optical film according to claim 1, wherein the shape of the base is a triangle or an equilateral triangle, and the shapes of the first surface, the second surface and the third surface are respectively a type of triangle. 3. The optical film according to claim 1, wherein the base has a first side, a second side and a third side connected to each other, and the first side, the second side and the third side arranged along the first side, the second side and the third side. 4. The optical film according to claim 3, wherein the lengths of the first side, the second side and the third side are substantially the same or different, or the first side, the second side and the third side Two of the sides have substantially the same length. 5. The optical film according to claim 3, wherein the lengths of the first side, the second side and the third side are about 10 μm to 100 μm. 6 . The optical film according to claim 3 , wherein the height of the pyramid of the triangular pyramid structure is the same as or different from the lengths of the first side, the second side and the third side. 7 . The optical film according to claim 1 , wherein the triangular prism-like structures are arranged at a distance from each other or are connected to each other, or the triangular prism-like structures are arranged in a staggered manner. 8 . The optical film according to claim 1 , wherein the triangular pyramid structure further has a fourth surface connected to the first surface, the second surface and the third surface opposite to the base. 9. The optical film according to claim 8, wherein the fourth surface is a flat surface, an inclined surface or an arc surface. 10. The optical film according to claim 1, wherein the substrate and the triangular-pyramid-like structure are formed integrally or bonded together. 11. The optical film according to claim 1, wherein the material of the optical film is polyethylene terephthalate, polycarbonate, polymethyl methacrylate or a transparent material. 12. The optical film according to claim 1, wherein the triangular pyramid structure is formed by soft pressing, hot pressing, hot rolling, ultraviolet curing, yellow-like light, electroforming, molding or micro-processing. 13. The optical film according to claim 1, further comprising an optical diffusion film disposed on the other surface of the substrate, wherein the other surface of the substrate is a light incident surface. 14. The optical film according to claim 13, wherein the material of the optical diffusion film comprises a mixture of light-transmitting resin and particles, or is a light-transmitting material. 15. The optical film of claim 13, wherein the optical diffusing film has a surface microstructure. 16. The optical film according to claim 1, wherein the triangular pyramid-like structures are arranged regularly, irregularly or randomly. 17. The optical film according to claim 1, wherein at least one of the first surface, the second surface, and the third surface forms an included angle with the base that is less than 90 degrees, or the first surface , at least two of the second surface and the third surface form an included angle of 90 degrees with the base. 18 . The optical film according to claim 1 , wherein one of the first surface, the second surface and the third surface of the triangular pyramid structure is a right triangle or an equilateral triangle. 19. The optical film according to claim 1, wherein the triangular pyramid-like structure is convex or concave on the substrate. 20. A backlight module, comprising: a light source emitting a light; and An optical film, arranged on an optical path of the light, and has a substrate and at least one type of triangular pyramid structure, the triangular pyramid structure is arranged on one side of the substrate, and the triangular pyramid structure has a base , a first surface, a second surface and a third surface, the first surface, the second surface and the third surface are connected to each other and arranged along the base. 21. The backlight module according to claim 20, further comprising a first diffuser disposed on one side of the optical film. 22. The backlight module according to claim 21, further comprising a light guide plate, disposed on the other side of the optical film relative to the first diffusion sheet, and disposed on one side of the light source, the light passes through the guide plate A light panel is directed towards the optical film. 23. The backlight module according to claim 21 , further comprising a second diffusion sheet disposed on the other side of the optical film relative to the first diffusion sheet, and the light source is disposed on the second diffusion sheet opposite to the optical film side.

Images