CN101131442A - Multi-layer light refraction diffusion element and backlight module using same - Google Patents

Abstract

A multilayer photorefractive diffusing optical element, comprising: a substrate having a first surface and a second surface opposite the first surface; at least two diffusion layers, wherein at least one diffusion layer is arranged on the first surface of the substrate, at least one diffusion layer is arranged on the second surface of the substrate, each diffusion layer comprises at least more than one diffusion particles with different particle sizes and optical materials, and the refractive index of the optical materials of each diffusion layer is different.

Description

Multilayer light refraction and diffusion element and backlight module using the element

technical field

The invention relates to a light refraction diffusion element and a backlight module using the diffusion element, in particular to a backlight module for a flat panel display.

Background technique

FIG. 1 shows a known edge-lit backlight module 1, which arranges a light source including a lamp reflector 12 and a cold-cathode tube 13 on the side of a light guide plate 11, and the light enters the light guide plate 11 and passes through the printed reflective dots 11a. The light is uniformly reflected, and part of the light is uniformly reflected by the reflection sheet 15, and then diffused and concentrated by the optical film 14 to form a uniform light source. Since the backlight module of this type is arranged on the side, space needs to be reserved to form the display, resulting in too large frame of the display, and the reserved space is limited, so it is impossible to install more light sources, which limits the improvement of luminance.

Another known technology, the direct type backlight module 2 shown in FIG. Uniform light source, wherein the lamp tube fixing seat assembly 24 fixes the cold cathode tube 22 on the back plate 25, and the back plate 25 is provided with a reflector 23 facing the surface of the cold cathode tube 22, which can provide a large number of light sources to improve brightness; however, due to It is directly installed in the light-emitting area, and a large space needs to be reserved in front of it, and it is covered with a polymer sheet with low light transmittance and high strength, and then a number of diffusion elements are placed to diffuse the light to avoid uneven light emission.

In this way, although the luminance can be greatly improved, in order to avoid uneven light diffusion and take into account the intensity requirements, the high-strength polymer sheet with low light transmittance has blocked most of the light, resulting in the need for more Multiple light sources can provide normal luminance, which leads to power consumption and heat dissipation problems. And because the optical diffusion film used is single-sided and single-layer, it must be used in multiple pieces to achieve the effect of diffusing light.

Contents of the invention

One of the objectives of the present invention is to provide strength through the transparent thin light guide plate to support the multi-layer light refraction and diffusion elements disposed on the surface of the light guide plate.

The second object of the present invention is to provide a combination of a transparent thin light guide plate and a multilayer light-refractive diffusion element to replace the diffuser plate with extremely poor light transmittance, so that light diffusion occurs in the multi-layer light-refractive diffusion element , so that the surface brightness can be improved.

The third object of the present invention is to provide a multilayer light refraction diffusion element, which shortens the path of diffused light and reduces the number of sheets used in the diffusion film. The multilayer light refraction diffusion element will be equal to multiple single-sided single-layer optical diffusion films Diffusion efficiency; this approach can reduce the original cost.

According to one aspect of the present invention, there is provided a multilayer light refraction and diffusion optical element, comprising: a substrate having a first surface and a second surface opposite to the first surface; at least two diffusion layers, wherein at least One diffusion layer is arranged on the first surface of the substrate, at least one diffusion layer is arranged on the second surface of the substrate, each diffusion layer includes at least one kind of diffusion particles and optical materials with different particle sizes, and each diffusion The optical materials of the layers have different refractive indices.

According to another aspect of the present invention, there is provided a backlight module, comprising the above-mentioned multi-layer optical element that refracts and diffuses light, and includes a light guide plate disposed under the optical element.

According to still another aspect of the present invention, there is provided a kind of multi-layer light refraction and diffusion optical element as mentioned above, wherein the substrate is a strengthened substrate, and a strengthening layer or at least one diffusion layer is arranged on the outermost surface of at least one diffusion layer For the enhanced diffusion layer.

According to yet another aspect of the present invention, there is provided a backlight module comprising the aforementioned multi-layer light-refractive-diffusion optical element with a strengthening structure.

Description of drawings

FIG. 1 is a schematic side view of a known edge-lit backlight module.

FIG. 2 is a perspective view of a known direct-lit backlight module.

FIG. 3 is a schematic cross-sectional view of the multi-layer light refraction and diffusion element according to the first embodiment of the present invention.

FIG. 4 is a schematic cross-sectional view of a multi-layer light refraction and diffusion element according to a second embodiment of the present invention.

FIG. 5 is a schematic perspective view of a backlight module using a transparent light guide plate of the present invention.

FIG. 6 is a schematic cross-sectional view of a multi-layer light refraction and diffusion element according to a third embodiment of the present invention.

FIG. 7 is a schematic cross-sectional view of a multilayer light refraction and diffusion element according to a fourth embodiment of the present invention.

FIG. 8 is a schematic cross-sectional view of a multi-layer light refraction and diffusion element according to a fifth embodiment of the present invention.

FIG. 9 is a schematic perspective view of a backlight module using the present invention without a transparent light guide plate.

Description of main component symbols

1 Edge-lit backlight module

11 Light guide plate

11a reflective dots

12 lamp reflector

13 cold cathode tube

14 Optical film

15 Reflectors

2 direct type backlight module

21 Diffusion plate

22 cold cathode tubes

23 reflector

24 Lamp tube fixing seat assembly

25 Backplane

3 multi-layer light refraction diffusion element

31 transparent substrate

32 upper diffusion layer

33 lower diffusion layer

4 The lower diffusion layer has a multi-layer light-refractive diffusion element

41 transparent substrate

42 upper diffusion layer

43 Lower Diffusion First Layer

44 Lower Diffusion 2nd Layer

45 Lower Diffusion Layer 3

5 direct type backlight module

51 light guide plate

52 cold cathode tubes

53 reflector

54 Lamp tube fixing seat assembly

55 Backplane

61 Reinforced transparent substrate

62 upper diffusion layer

63 lower diffusion layer

71 transparent substrate

72 upper diffusion layer

73 lower diffusion layer

74 Reinforcement layer

81 transparent substrate

82 Reinforced Upper Diffusion Layer

83 lower diffusion layer

9 Direct type backlight module

92 cold cathode tubes

93 reflector

94 Lamp tube fixing seat assembly

95 Backplane

Detailed ways

In order to make the above objects, functional features, and advantages of the present invention more clearly understood, the present invention will be described in detail below through preferred embodiments in conjunction with the accompanying drawings.

Please refer to Fig. 3, it is the multi-layer light refraction diffusion element 3 of the first embodiment of the present invention, comprises transparent substrate 31, and this transparent substrate 31 can be the following materials, but not limited to following materials: polystyrene, polyacrylonitrile methyl acrylate, polycarbonate, polyethylene, polypropylene, polyvinyl chloride, epoxy resin or polyethylene terephthalate, preferably, the surface of the substrate 31 can also be roughened to make the surface A certain roughness to increase its diffusion effect. The upper and lower surfaces of the transparent substrate 31 are uniformly coated with diffusion layers: an upper diffusion layer 32 and a lower diffusion layer 33 . The upper diffusion layer 32 and the lower diffusion layer 33 are formed by mixing at least one kind of diffusion particles with different particle sizes and optical materials. The diffusion particles can be of any shape, and the average diameter of the diffusion particles is 20-80 μm, preferably 25-40 μm, and the material of the diffusion particles can be light-transmitting organic synthetic resin, metal, air and compound One of. The optical material includes light-transmitting organic synthetic resin, such as thermoplastic optical plastic or UV-hardened light-curing plastic. Wherein the haze of the upper diffusion layer 32 is between 30% and 60%; while the haze of the lower diffusion layer 33 is about 80%, the refractive index of the lower diffusion layer 33 is different from that of the upper diffusion layer 3 2, The difference should be greater than 0.2 or more.

Please refer to the multi-layer light refraction diffusion element 4 of the second embodiment of FIG. 4, the main difference between it and the first embodiment of FIG. The layer design includes a first layer 43 , a second layer 44 and a third layer 45 , and the refractive index of every two adjacent diffusion layers is different, and the difference should be greater than 0.2.

As shown in FIG. 5 , the direct-type backlight module structure 5 using the multilayer light refraction and diffusion elements of the first embodiment and the second embodiment includes a backplane 55 with reflective sheets 53 arranged on its surface, and the two ends of the backplane 55 are A lamp tube fixing seat assembly 54 is provided to fix the cold cathode tube 52; a transparent light guide plate 51 is placed above it, and then a multi-layer light refraction and diffusion element 3 (or 4) is placed to complete the structure 5 . The material of the light guide plate 51 can be polystyrene, polymethyl methacrylate, polycarbonate, polyethylene, polypropylene, polyvinyl chloride, epoxy resin, polyethylene terephthalate or acrylic . Because when the light penetrates the transparent light guide plate 51, the light refraction occurs in the multi-layer light refraction and diffusion elements, and the overall light penetration rate reaches over 70%, while the original light penetration rate of the diffusion plate is only 30% to 40%. , in addition to greatly reducing the cost, the front brightness is also better than the original design.

Please refer to FIG. 6, the multilayer light refraction diffusion element 6 of the third embodiment of the present invention, its main difference from the first embodiment in FIG. The thickness of the transparent substrate 31 in the first embodiment, the addition of fibers during the manufacture of the transparent substrate 31, or a combination of the foregoing methods increase the hardness and strength of the transparent substrate 61 and are not easily bent.

Fig. 7 is the multilayer light refraction diffusion element 7 of the fourth embodiment of the present invention, and its main difference with the first example of Fig. 3 is that the upper surface of the upper diffusion layer 72 (or the lower surface of the lower diffusion layer 73, or simultaneously on the upper surface The upper surface of the diffusion layer 72 and the lower surface of the lower diffusion layer 73) form a strengthening layer 74, and the structure of the strengthening layer 74 can be a honeycomb shape, a plurality of straight lines, a plurality of horizontal lines, a lattice shape, an X shape, a diagonal strip shape, etc. Any pattern is formed to provide sufficient strength to support the multi-layered light-refractive diffusion element 7 . The material of the reinforcement layer 74 can be the same as that of the upper diffusion layer 72 or the lower diffusion layer 73 or can include reinforcement materials such as long fibers and glass fibers.

Fig. 8 is a multi-layer light refraction diffusion element 8 of the fifth embodiment of the present invention. The main difference between it and the first embodiment in Fig. 3 is that it includes a strengthened upper diffusion layer 82 (or the lower diffusion layer 83 is strengthened, or The diffusion layer 82 and the lower diffusion layer 83 are strengthened), and the upper diffusion layer 82 can be formed by adding hardness-enhancing materials to the upper diffusion layer 32 of the first embodiment, such as diffusion glue, metal, polymer, derivatives and other materials , so as to avoid the bending of the diffusion layer, thereby increasing the strength or hardness of the multilayer light-refractive diffusion element 8 .

The aforementioned third to fifth embodiments of Fig. 6 to Fig. 8 are various multi-layer light refraction and diffusion elements with strengthening structures formed by changing the first embodiment of Fig. 3, and the second embodiment of Fig. 4 can be further Change it to form various multi-layer light refraction diffusion elements with strengthened structures, wherein the upper diffusion layer or/and the lower diffusion layer are multi-layer designs, and the refractive index of every two adjacent diffusion layers is different, and the difference should be greater than 0.2 above.

In addition, the third to fifth embodiments in FIGS. 6 to 8 can also be combined and changed. For example, the third and fourth embodiments in FIGS. 6 and 7 can be combined to form a strengthened transparent substrate 61 and a strengthening layer 74. The multi-layer light refraction and diffusion element can also be further combined and changed in conjunction with the second embodiment in FIG. 4 .

As shown in Figure 9, the backlight module structure 9 using any one of the multilayer light refraction and diffusion elements in the third to fifth embodiments and the aforementioned various changes includes a back plate 95, a reflective sheet 93 is arranged on its surface, and the back plate 95 Both ends are provided with a lamp tube fixing seat assembly 94 for fixing the cold cathode tube 92; the above-mentioned strengthened multi-layer light refraction and diffusion element 6 (or 7, 8) is placed above it, so that no additional installation is required. The transparent light guide plate completes the structure 9 . According to this rule, the present invention can achieve the goals of better luminance, luminous uniformity and thinning.

Although the present invention has been disclosed in detail using the above-mentioned preferred embodiments, these embodiments are not intended to limit the present invention, and those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Modifications, therefore, the protection scope of the present invention is defined by the appended claims.

Claims (21)

1. An optical element for multilayer light refraction and diffusion, comprising: a substrate having a first surface and a second surface opposite to the first surface; At least two diffusion layers, wherein at least one diffusion layer is arranged on the first surface of the substrate, at least one diffusion layer is arranged on the second surface of the substrate, and each diffusion layer includes at least one kind of diffusion particles with different particle sizes and optical materials, and the optical materials of each diffusion layer have different refractive indices. 2. The multilayer light-refractive-diffusion optical element as claimed in claim 1, wherein the substrate is light-transmissive. 3. The optical element of multilayer light refraction and diffusion as claimed in claim 1, wherein the material of the substrate is polystyrene, polymethyl methacrylate, polycarbonate, polyethylene, polypropylene, polyvinyl chloride, Epoxy or polyethylene terephthalate. 4. The multi-layer light refracting and diffusing optical element as claimed in claim 1, wherein the first surface or the second surface of the substrate has a certain roughness. 5. The multi-layer light-refractive-diffusion optical element as claimed in claim 1, wherein the diffusion particles can be of any shape. 6. The multi-layer light-refractive-diffusion optical element as claimed in claim 1, wherein the average diameter of the diffusion particles is 20 μm˜80 μm. 7. The optical element of multi-layer light refraction and diffusion as claimed in claim 1, wherein the difference in refractive index between each diffusion layer is greater than or equal to 0.2. 8. The multilayer light-refractive-diffusion optical element according to claim 1, wherein at least one diffusion layer disposed on the first surface has a haze ranging from 30% to 60%, and is disposed on at least one of the second surface The haze range for one diffusion layer is around 80%. 9. The multi-layer light refracting and diffusing optical element as claimed in claim 1, wherein the material of the diffusing particles is selected from one of light-permeable organic synthetic resins, metals, air and compounds. 10. The multi-layer light refracting and diffusing optical element as claimed in claim 1, wherein the optical material is a light-transmitting organic synthetic resin. 11. The multilayer light-refractive-diffusion optical element as claimed in claim 9, wherein the synthetic resin is thermoplastic optical plastic or UV-curable light-curable plastic. 12. The optical element of multilayer light refraction and diffusion as claimed in claim 1, wherein the substrate is a strengthened substrate, which is obtained by increasing the thickness of the substrate, adding fibers to the substrate or combining the aforementioned reinforced substrates And the way to add fiber to form. 13 . The multilayer light refracting and diffusing optical element according to claim 1 , further comprising a strengthening layer disposed on the outermost surface of the diffusing layer on the first surface or/and the second surface of the substrate. 14 . 14. The optical element with multi-layer light refraction and diffusion as claimed in claim 13, wherein the structure of the strengthening layer can be any pattern such as honeycomb shape, multiple straight lines, multiple horizontal lines, grid shape, X shape, oblique stripe shape, etc. form. 15. The multi-layer light-refractive-diffusion optical element as claimed in claim 13, wherein the material of the reinforcement layer can be the same as that of the diffusion layer or can be a reinforcement material such as long fiber, glass fiber and the like. 16. The optical element of multilayer light refraction and diffusion as claimed in claim 1, wherein at least one diffusion layer is a strengthened diffusion layer, which is obtained by adding diffusion glue, metal, polymer or derivatives, etc. to the at least one diffusion layer material to form. 17. A backlight module, comprising the multi-layer light refracting and diffusing optical element according to any one of claims 1 to 11, and comprising a light guide plate disposed under the optical element. 18. A backlight module comprising the multi-layer light refracting and diffusing optical element according to any one of claims 12-16. 19. The backlight module of claim 18, further comprising a light guide plate. 20. The backlight module as claimed in claim 17 or 19, wherein the material of the light guide plate is polystyrene, polymethyl methacrylate, polycarbonate, polyethylene, polypropylene, polyvinyl chloride, epoxy resin, Polyethylene terephthalate or acrylic. 21. The backlight module as claimed in claim 17 or 19, wherein the light guide plate is transparent.

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