USRE38243EExpiredUtilityPatentIndex 89

Plane light source unit

Assignee: MITSUBISHI RAYON COPriority: Nov 12, 1987Filed: Jul 2, 1997Granted: Sep 2, 2003

Est. expiryNov 12, 2007(expired)· nominal 20-yr term from priority

Inventors:OE MAKOTO CHIBA ITHUSSEI

G02B 6/0033G02B 6/0071G02B 6/0068G02B 6/0001G02B 6/04G02B 6/0038G02B 6/0055G02B 6/0053G02F 1/01G09F 13/18G02F 1/133

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Claims

Abstract

A plane light source unit is provided which comprises a first element having a light incident face at least at one side end thereof and a first light emitting surface extending perpendicularly to the light incident face, the first element further having a reflecting layer provided on a surface thereof opposite to the first light emitting surface, and a second element having a light incident surface which receives the light emitted by the first element and a second light emitting surface through which light is emitted in a predetermined direction, the first light emitting surface and/or the opposite surface of the first element having a directive function to cause incident light through the light incident face to emit through the first light emitting surface in a direction oblique to the direction of the light, the second element having a large number of prism units formed on the light incident surface thereof. The plane light source unit is advantageously used as a backlighting means for a liquid crystal display device or the like.

Claims

exact text as granted — not AI-modified

We claim:

1. A plane light source unit, comprising a first element having a light incident face at lest at one side end thereof and a first light emitting surface extending perpendicularly to said light incident face, such first element further having a reflecting layer provided on a surface thereof opposite to said first light emitting surface, and a second element having a light incident surface which receives the light emitted by said first element and a second light emitting surface through which light is emitted in a predetermined direction, at least one of said first light emitting surface and the opposite surface of said first element comprising means having a directive function to cause incident light through said light incident face to emit through said first light emitting surface in two preferential directions oblique to, and on opposite sides of, a normal line thereof, said second element having a large number of prism units formed on said light incident surface thereof, each prism unit having at least one surface positioned for effecting total reflection of the light received by said second element,
wherein the direction of substantially all of the light emitting from said second element makes an angle ranging from 0 degrees to 20 degrees with respect to a normal line of said first light emitting surface of said first element.

2. A plane light source unit according to claim 1 , wherein either said first light emitting surface or the opposite surface of said first element has a large number of lens units formed thereon which contribute to the directive function.

3. A plane light source unit according to claim 2 , wherein said large number of lens units are convex cylindrical lenticular lenses.

4. A plane light source unit according to claim 2 , wherein said large number of lens units are concave cylindrical lenticular lenses.

5. A plane light source unit according to claim 2 , wherein said large number of lens units are triangular pole-shaped lenticular lenses.

6. A plane light source unit according to claim 2 , wherein said large number of lens units are polygonal pole-shaped lenticular lenses.

7. A plane light source unit according to claim 2 , wherein said large number of lens units are anisotropic lenticular lenses.

8. A plane light source unit according to claim 1 , wherein said first light emitting surface and/or the opposite surface of said first element has a mat finished surface which extends substantially in parallel to a plane of said reflecting layer and contribute to the directive function.

9. A plane light source unit according to claim 8 , wherein a haze of said first element on which said mat finished surface is formed is equal to or greater than 30 percent.

10. A plane light source unit according to claim 1 , wherein said first element has a pair of light incident surfaces at two opposing side ends thereof.

11. A plane light source unit according to claim 1 , wherein said first element is made of an acrylic resin material.

12. A plane light source unit according to claim 1 , wherein said first element is made of a polycarbonate resin material.

13. A plane light source unit according to claim 1 , wherein said second element is made of an acrylic resin material.

14. A plane light source unit according to claim 1 , wherein said second element is made of a polycarbonate resin material.

15. A plane light source unit according to claim 1 , wherein the direction of light emitting from said first element makes an angle equal to or greater than 45 degrees and smaller than 90 degrees with respect to a normal line of said first light emitting surface of said first element.

16. A plane light source unit comprising:

a first element having a light incident face at least at one side end thereof, a first light emitting surface extending perpendicularly to said light incident face, and an opposite surface opposite to said first light emitting surface,

at least one of the first light emitting surface and the opposite surface comprising means having a directive function to cause incident light through the light incident face to emit through the first light emitting surface in a direction oblique to a line normal to the first light emitting surface;

a reflecting layer provided adjacent the opposite surface of said first element,

a second element having a large number of prism units, each prism unit having at least one surface for effecting total reflection of the light received by the second element, said second element including a light incident surface and a second light emitting surface through which light is emitted in a predetermined direction, wherein the direction of substantially all light emitting from said second element makes an angle ranging from 0 degrees to 50 degrees with respect to the line normal to the first light emitting surface of said first element.

17. A plane light source unit according to claim 16 , wherein said means having a directive function is distributed over the first light emitting surface.

18. A plane light source unit according to claim 16 , wherein one of the light incident surface and the second light emitting surface includes said large number of prism units and the other of the light incident surface and the second light emitting surface is flat.

19. A plane light source unit according to claim 16 , wherein at least one of the light incident surface and the second light emitting surface includes said large number of prism units.

20. A plane light source unit according to claim 16 , wherein the direction of substantially all light emitting from said second element makes an angle ranging from 0 degrees to 40 degrees with respect to the line normal to the first light emitting surface of said first element.

21. A plane light source unit according to claim 20 , wherein said means having a directive function is distributed over the first light emitting surface.

22. A plane light source unit according to claim 20 , wherein one of the light incident surface and the second light emitting surface includes said large number of prism units and the other of the light incident surface and the second light emitting surface is flat.

23. A plane light source unit according to claim 20 , wherein at least one of the light incident surface and the second light emitting surface includes said large number of prism units.

24. A plane light source unit according to claim 16 , wherein the direction of substantially all light emitting from said second element makes an angle ranging from 0 degrees to 30 degrees with respect to the line normal to the first light emitting surface of said first element.

25. A plane light source unit according to claim 24 , wherein said means having a directive function is distributed over the first light emitting surface.

26. A plane light source unit according to claim 24 , wherein one of the light incident surface and the second light emitting surface includes said large number of prism units and the other of the light incident surface and the second light emitting surface is flat.

27. A plane light source according to claim 24 , wherein at least one of the light incident surface and the second light emitting surface includes said large number of prism units.

28. A plane light source unit according to claim 16 , wherein the direction of substantially all light emitting from said second element makes an angle ranging from 0 degrees to 20 degrees with respect to the line normal to the first light emitting surface of said first element.

29. A plane light source unit according to claim 28 , wherein said means having a directive function is distributed over the first light emitting surface.

30. A plane light source unit according to claim 28 , wherein one of the light incident surface and the second light emitting surface includes said large number of prism units and the other of the light incident surface and the second light emitting surface is flat.

31. A plane light source unit according to claim 28 , wherein at least one of the light incident surface and the second light emitting surface includes said large number of prism units.

32. A plane light source unit according to claim 16 , wherein said prism units are triangular prism units.

33. A plane light source unit according to claim 32 , wherein said triangular prism units are isosceles triangular prism units.

34. A plane light source unit comprising:

a reflecting layer provided adjacent the opposite surface of said first element,

a second element having a large number of prism units, each prism unit having at least one surface for effecting total reflection of the light received by the second element, said second element including a light incident surface and a second light emitting surface through which light is emitted in a predetermined direction, wherein an angle at which the maximum luminance value is observed is from 0 degrees to 20 degrees with respect to the line normal to the first light emitting surface of said first element.

35. A plane light source unit according to claim 34 , wherein said means having a directive function is distributed over the first light emitting surface.

36. A plane light source unit according to claim 34 , wherein one of the light incident surface and the second light emitting surface includes said large number of prism units and the other of the light incident surface and the second light emitting surface is flat.

37. A plane light source unit according to claim 34 , wherein at least one of the light incident surface and the second light emitting surface includes said large number of prism units.

38. A plane light source unit according to claim 34 , wherein said prism units are triangular prism units.

39. A plane light source unit according to claim 38 , wherein said triangular prism units are isosceles triangular prism units.

40. A plane light source unit comprising:

a reflecting layer provided adjacent the opposite surface of first element,

a second element having a large number of substantially triangular prism units, each prism unit having at least one surface for effecting total reflection of the light received by the second element, said second element including a light incident surface and a second light emitting surface through which light is emitted in a predetermined direction.

41. A plane light source unit according to claim 40 , wherein said means having a directive function is distributed over the first light emitting surface.

42. A plane light source unit according to claim 40 , wherein one of the light incident surface and the second light emitting surface includes said large number of prism units and the other of the light incident surface and the second light emitting surface is flat.

43. A plane light source unit according to claim 40 , wherein at least one of the light incident surface and the second light emitting surface includes said large number of prism units.

44. A plane light source unit according to any one of claims 41 - 43 , wherein said triangular prism units are isosceles prism units.

45. A plane light source unit according to any one of claims 16 - 31 , 34 - 43 , wherein said second element comprises an acrylic resin material.

46. A plane light source unit according to any one of claims 16 - 31 , 34 - 43 , wherein said second element comprises a polycarbonate resin material.

47. A plane light source according to any one of claims 16 - 31 , 34 - 43 , wherein the light incident surface of said second element includes said large number of prism units.

48. A plane light source unit according to any one of claims 16 - 31 , 34 - 43 , wherein the first light emitting surface of said first element has one of a roughened surface, a plurality of convex lenses, and a plurality of concave lenses.

49. A plane light source unit according to any one of claims 16 - 31 , 34 - 43 , wherein the opposite surface of said first element has one of a roughened surface, a plurality of convex lenses, and a plurality of concave lenses.

50. A plane light source unit according to any one of claims 16 - 31 , 34 - 43 , wherein the first light emitting surface of said first element is flat.

51. A plane light source unit according to any one of claims 16 - 31 , 34 - 43 , wherein the opposite surface of said first element is flat.

52. A plane light source unit according to any one of claims 16 - 31 , 34 - 43 , wherein said second element is disposed directly on the first light emitting surface of said first element.

53. A plane light source unit according to any one of claims 16 - 31 , 34 - 43 , wherein said reflecting layer is disposed directly on the opposite surface of said first element.

54. A plane light source unit according to any one of claims 16 - 31 , 34 - 43 , wherein said first element is a plate having a uniform thickness.

55. A backlighting arrangement for a liquid crystal display device comprising:

a light guide having a light incident face at least at one side end thereof and a light emitting surface extending substantially perpendicularly to said light incident face;

a lamp disposed adjacent to said light incident face of said light guide, said lamp generating light for illuminating the liquid crystal display device;

a reflecting layer disposed adjacent a surface of said light guide opposite the light emitting surface;

a prismatic element disposed over the light emitting surface of said light guide, said prismatic element having a first surface and a second surface opposite the first surface, at least one of the first surface and the second surface having a large number of prism units formed thereon, each prism unit having at least one surface for effecting total reflection of the light received by said prismatic element; and

a light directive pattern between said reflecting layer and said prismatic element, the light directive pattern causing light entering said light guide through the light incident face to emit from the light emitting surface of said light guide in a direction oblique to a line normal to the light emitting surface,

wherein the direction of substantially all light emitting from said prismatic element makes an angle ranging from 0 degrees to 50 degrees with respect to the line normal to the light emitting surface of said light guide.

56. A backlighting arrangement for a liquid crystal display device according to claim 55 , wherein the direction of substantially all light emitting from said second element makes an angle ranging from 0 degrees to 40 degrees with respect to the line normal to the first light emitting surface of said first element.

57. A backlighting arrangement for a liquid crystal display device according to claim 55 , wherein the direction of substantially all light emitting from said second element makes an angle ranging from 0 degrees to 30 degrees with respect to the line normal to the first light emitting surface of said first element.

58. A backlighting arrangement for a liquid crystal display device according to claim 55 , wherein the direction of substantially all light emitting from said second element makes an angle ranging from 0 degrees to 20 degrees with respect to the line normal to the first light emitting surface to said first element.

59. A backlighting arrangement for a liquid crystal display device comprising:

a light guide having a light incident face at least at one side end thereof and a light emitting surface extending substantially perpendicularly to said light incident face;

a lamp disposed adjacent to said light incident face of said light guide, said lamp generating light for illuminating the liquid crystal display device;

a reflecting layer disposed adjacent a surface of said light guide opposite the light emitting surface;

wherein an angle at which the maximum luminance value is observed is from 0 degrees to 20 degrees with respect to the line normal to the light emitting surface of said light guide.

60. A backlighting arrangement for a liquid crystal display device according to any one of claims 55 - 59 , wherein said light directive pattern is formed on the light emitting surface of said light guide.

61. A backlighting arrangement for a liquid crystal display device according to any one of claims 55 - 59 , wherein said light guide and said light directive pattern are formed by a single structural element.

62. A backlighting arrangement for a liquid crystal display device according to any one of claims 55 - 59 , wherein said second surface of said prismatic element faces said light emitting surface of said light guide.

63. A backlighting arrangement for a liquid crystal display device according to any one of claims 55 - 59 , wherein said prismatic element is disposed directly on said light emitting surface of said light guide.

64. A backlighting arrangement for a liquid crystal display device according to any one of claims 55 - 59 , wherein said reflecting layer is disposed directly on said surface opposite to said light emitting surface of said light guide.

65. A backlighting arrangement for a liquid crystal display device according to any one of claims 55 - 59 , wherein said light guide is a plate having a uniform thickness.

66. A backlighting arrangement for a liquid crystal display device according to any one of claims 55 - 59 , wherein said light directive pattern comprises one of a plurality of convex lenses, a plurality of concave lenses, and a roughened finish formed on the light emitting surface of said light guide.

67. A backlighting arrangement for a liquid crystal display device according to any one of claims 55 - 59 , wherein said light directive pattern comprises one of a plurality of convex lenses, a plurality of concave lenses, and a roughened finish formed on the surface opposite the light emitting surface of said light guide.

68. A backlighting arrangement for a liquid crystal display device according to any one of claims 55 - 59 , wherein said prism units are triangular prisms.

69. A backlighting arrangement for a liquid crystal display device according to claim 68 , wherein said triangular prisms are isosceles.

70. A backlighting arrangement for a liquid crystal display device according to any one of claims 55 - 59 , wherein said prismatic element comprises an acrylic resin material.

71. A backlighting arrangement for a liquid crystal display device according to any one of claims 55 - 59 , wherein said prismatic element comprises a polycarbonate resin material.

72. A backlighting arrangement for a liquid crystal display device according to any one of claims 55 - 59 , wherein said light emitting surface is flat.

73. A backlighting arrangement for a liquid crystal display device according to any one of claims 55 - 59 , wherein said surface opposite to said light emitting surface is flat.

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