Brightness enhancement film having a light-guiding structure

• US 7,269,328 B2
• Filed: 09/20/2005
• Issued: 09/11/2007
• Est. Priority Date: 09/13/2005
• Status: Active Grant

• Current Assignee: Zhejiang Jinhui Optoelectronic Material Co., Ltd
• Original Assignee: EFON Technology Company Limited
• Inventors: Tang, Shih-Chieh
• Primary Examiner(s): Font; Frank G.
• Assistant Examiner(s): PENG, CHARLIE YU
• Application Number:
  US11/162,703
• Publication Number:
  US 20070058920A1
• Time in Patent Office: 721 Days
• Field of Search: 385/901, 385/31, 385/36, 385/37, 385/146, 385/147, 359/575, 359/619, 362/27, 362/31, 349/64, 349/65
• US Class Current: 385/146
• CPC Class Codes: G02B 6/0036 2-D arrangement of prisms, protrusions, indentations or roughened surfaces
• CPC Class Codes: G02B 6/0038 Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: Y10S 385/901 Illuminating or display apparatus

Abstract

A brightness enhancement film having a light-guiding structure includes a substrate, which has a light-guiding layer and a plurality of light-refracting microstructures. The substrate has a light incident surface and a light emission surface opposite thereto. The light-refracting microstructures are arranged on the light incident surface of the substrate and are provided for varying surface curvatures to refract incident light. The light-guiding layer is arranged on the light emission surface of the substrate and is provided for guiding refracted light to generate homogeneous light to emit therefrom.

Claims

1. A brightness enhancement film having a light-guiding structure comprising:

a substrate having a light incident surface and a light emission surface, the substrate made from a first transparent material which permits penetrating light through the substrate;

a light-refracting layer arranged on the light incident surface of the substrate, the light-refracting layer providing changes in curvature so as to refract the light projecting from a light source;

a light-guiding layer formed between the light incident surface and the light emission surface of the substrate so as to guide the refracted light transmitting from the light incident surface to the light emission surface; and

a reinforcing layer formed on the light emission surface of the substrate, said reinforcing layer being made from a second transparent material while the light-guiding layer of the substrate is made from the first transparent material;

wherein the reinforcing layer has a thickness which can be selectively changed depending on that of the light-guiding layer.

2. The brightness enhancement film having the light-guiding structure as defined in claim 1, wherein the light-guiding layer and the light-refracting layer are made from the same transparent material, and the light-refracting layer is directly formed on the light-guiding layer.

3. The brightness enhancement film having the light-guiding structure as defined in claim 1, wherein the light-guiding layer and the light-refracting layer are separately made from different transparent materials and adhered to each other.

4. The brightness enhancement film having the light-guiding structure as defined in claim 1, wherein the reinforcing layer has a hardness greater than that of the substrate such that the reinforcing layer protects the light emission surface of the substrate.

7. The brightness enhancement film having the light-guiding structure as defined in claim 1, wherein the second transparent material is selected from a low refractive transparent material relative to that of the first transparent material.

8. The brightness enhancement film having the light-guiding structure as defined in claim 7, wherein the second transparent material is selected from acrylic resin.

9. The brightness enhancement film having the light-guiding structure as defined in claim 1, wherein the reinforcing layer has a thickness ranging between 5 μ

m and 10 μ

m.

10. The brightness enhancement film having the light-guiding structure as defined in claim 1, wherein the reinforcing layer covers the light emission surface of the substrate to form a composite reinforced laminate by coating.

11. The brightness enhancement film having the light-guiding structure as defined in claim 1, wherein the reinforcing layer covers the light emission surface of the substrate to form a composite reinforced laminate by adhesive.

12. The brightness enhancement film having the light-guiding structure as defined in claim 1, wherein the reinforcing layer covers the light emission surface of the substrate to form a composite reinforced laminate by physical vapor deposition or sputtering deposition.

13. The brightness enhancement film having the light-guiding structure as defined in claim 1, wherein the light-refracting layer consists of a plurality of prism units, and each of which consists of a first flat inclined surface and a second flat inclined surface.

14. The brightness enhancement film having the light-guiding structure as defined in claim 13, wherein an included angle is formed between the first flat inclined surface and the second flat inclined surface of the light-refracting layer, and the included angle ranges between 60 degrees and 75 degrees.

15. The brightness enhancement film having the light-guiding structure as defined in claim 1, wherein the light-refracting layer consists of a plurality of micro-hemispheres.

16. The brightness enhancement film having the light-guiding structure as defined in claim 15, wherein the micro-hemispheres are arranged to form a plurality of hexagonal units in a hexagonal manner such that each of the micro-hemispheres has six of the adjacent micro-hemispheres.

17. The brightness enhancement film having the light-guiding structure as defined in claim 1, wherein the light-refracting microstructure layer consists of a plurality of micro cones.

18. The brightness enhancement film having the light-guiding structure as defined in claim 17, wherein the micro cones are arranged to form a plurality of hexagonal units in a hexagonal manner such that each of the micro cones has six of the adjacent micro cones.

19. The brightness enhancement film having the light-guiding structure as defined in claim 1, wherein the light-refracting layer consists of a plurality of micro rippled ridges, and each of which consists of a plurality of micro light-condensing units substantially having a common height, each of the micro light-condensing units further has a pair of curved surfaces a pair of common trough lines and a common ridge line.

20. The brightness enhancement film having the light-guiding structure as defined in claim 19, wherein the trough line of the micro light-condensing unit is substantially constructed from a straight line.

21. The brightness enhancement film having the light-guiding structure as defined in claim 19, wherein the trough line of the micro light-condensing unit is substantially constructed from a curved line.

22. The brightness enhancement film having the light-guiding structure as defined in claim 19, wherein the common ridgeline of the micro light-condensing unit is substantially constructed from a curved line.

23. The brightness enhancement film having the light-guiding structure as defined in claim 1, wherein the light-refracting layer consists of a plurality of curved prism units, and each of which having a pair of meandering surfaces, a pair of common trough lines and a common ridge.

24. The brightness enhancement film having the light-guiding structure as defined in claim 23, wherein each of the curved prisms substantially has a common vertical height and a common horizontal width such that each of the meandering surfaces of the curved prisms substantially has the same changes in curvature.

25. The brightness enhancement film having the light-guiding structure as defined in claim 23, wherein each of the curved prisms substantially has a common vertical height but varies in horizontal widths such that each of the meandering surfaces of the curved prisms varies in curvature.

26. The brightness enhancement film having the light-guiding structure as defined in claim 23, wherein each of the curved prisms substantially has a common horizontal width but varies in vertical heights such that each of the meandering surfaces of the curved prisms varies in curvature.

27. The brightness enhancement film having the light-guiding structure as defined in claim 23, wherein at least one of the meandering surfaces consists of a plurality of lateral ridges arranged in staggered mariner in a longitudinal direction to provide changes in curvature.

28. The brightness enhancement film having the light-guiding structure as defined in claim 1, wherein the light-refracting layer is integrally formed on the light incident surface of the substrate.

29. The brightness enhancement film having the light-guiding structure as defined in claim 1, wherein the light-refracting layer and the substrate are adhered to each other.

30. The brightness enhancement film having the light-guiding structure as defined in claim 1, wherein the first transparent material is selected from an epoxy or UV curable adhesive.

5. A brightness enhancement film having a light-guiding structure comprising:

a substrate having a light incident surface and a light emission surface, the substrate made from a first transparent material which permits penetrating light through the substrate;

a light-refracting layer arranged on the light incident surface of the substrate, the light-refracting layer providing changes in curvature so as to refract the light projecting from a light source;

a light-guiding layer formed between the light incident surface and the light emission surface of the substrate so as to guide the refracted light transmitting from the light incident surface to the light emission surface; and

a reinforcing layer formed on the light emission surface of the substrate, said reinforcing layer being made from a second transparent material while the light-guiding layer of the substrate is made from the first transparent material;

wherein the second transparent material of the reinforcing layer has a rate of shrinkage substantially approximate to that of the substrate.

31. The brightness enhancement film having the light-guiding structure as defined in claim 5, wherein the reinforcing layer has a hardness greater than that of the substrate.

32. The brightness enhancement film having the light-guiding structure as defined in claim 5, wherein the second transparent material is selected from a low refractive transparent material relative to that of the first transparent material.

6. A brightness enhancement film having a light-guiding structure comprising:

a substrate having a light incident surface and a light emission surface, the substrate made from a first transparent material which permits penetrating light through the substrate;

a light-refracting layer arranged on the light incident surface of the substrate, the light-refracting layer providing changes in curvature so as to refract the light projecting from a light source;

a light-guiding layer formed between the light incident surface and the light emission surface of the substrate so as to guide the refracted tight transmitting from the light incident surface to the light emission surface; and

a reinforcing layer formed on the light emission surface of the substrate, said reinforcing layer being made from a second transparent material while the light-guiding layer of the substrate is made from the first transparent material;

wherein the first transparent material has a first refractive index and the second transparent material has a second refractive index, the first refractive index is greater than the second refractive index.