Light redirecting films and film systems

• US 20010053075A1
• Filed: 07/19/2001
• Published: 12/20/2001
• Est. Priority Date: 02/23/1999
• Status: Active Grant

• Current Assignee: Delaware Display Group LLC (Acacia Research Corporation)
• Original Assignee: Solid State Opto Limited (Global Lighting Technologies Inc.)
• Inventors: McCollum, Timothy A., Parker, Jeffery R., Ezell, Robert M.
• Granted Patent: US 6,752,505 B2
• Time in Patent Office: Days
• US Class Current: 362/617
• CPC Class Codes: A61B 2090/309 using white LEDs
• CPC Class Codes: A61M 2021/0044 by the sight sense
• CPC Class Codes: A61M 21/02 for inducing sleep or relaxation, e.g. by direct nerve stimulation, hypnosis, analgesia for massage A61H; electrotherapy A61N, e.g. applying alternating or intermittent electric currents for producing anaesthesia A61N1/36021
• CPC Class Codes: A61N 2005/063 comprising light transmitting means, e.g. optical fibres
• CPC Class Codes: A61N 2005/0652 Arrays of diodes
• CPC Class Codes: A61N 5/0621 Hyperbilirubinemia, jaundice treatment
• CPC Class Codes: F21V 11/00 Screens not covered by groups F21V1/00, F21V3/00, F21V7/00 or F21V9/00 characterised by cooling arrangements F21V29/502
• CPC Class Codes: F21V 5/10 comprising photoluminescent material
• CPC Class Codes: G02B 6/0018 Redirecting means on the surface of the light guide
• CPC Class Codes: G02B 6/002 by shaping at least a portion of the light guide, e.g. with collimating, focussing or diverging surfaces
• CPC Class Codes: G02B 6/0021 for housing at least a part of the light source, e.g. by forming holes or recesses
• CPC Class Codes: G02B 6/0028 Light guide, e.g. taper
• CPC Class Codes: G02B 6/0031 Reflecting element, sheet or layer
• 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 6/0043 provided on the surface of the light guide
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02B 6/006 to produce indicia, symbols, texts or the like
• CPC Class Codes: G02B 6/0061 to provide homogeneous light output intensity
• CPC Class Codes: G02B 6/0065 Manufacturing aspects; Material aspects
• CPC Class Codes: G02B 6/0068 : Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: H01H 2219/062 : Light conductor
• CPC Class Codes: H01H 2221/07 : transparent

Abstract

Light redirecting films include a pattern of individual optical elements of well defined shape on the light exit surface of the films for refracting the light entering the entrance surface of the films from a backlight toward a direction normal to the exit surface. The individual optical elements overlap and intersect each other. Also, the orientation, size and/or shape of the optical elements may be tailored to redirect more of the incident light from the backlight within a desired viewing angle.

Claims

1. A light redirecting film comprising a thin optically transparent substrate having individual optical elements of well defined shape to redistribute light passing through the substrate toward a direction normal to the substrate, at least some of the optical elements having at least one curved surface and at least one planar surface for redistributing light along two different axes, at least some of the optical elements overlapping each other.

2. The film of

claim 1

wherein at least some of the optical elements are staggered with respect to each other.

3. The film of

claim 1

wherein at least some of the optical elements intersect each other.

4. The film of

claim 1

wherein at least some of the optical elements interlock each other.

5. A light redirecting film comprising a thin optically transparent substrate having individual optical elements of well defined shape to redistribute light passing through the substrate toward a direction normal to the substrate, at least some of the optical elements having at least one curved surface and at least one planar surface for redistributing light along two different axes, the curved surface of at least some of the optical elements having a different perimeter shape than a perimeter shape of the planar surface.

6. A light redirecting film comprising a thin optically transparent substrate having individual optical elements of well defined shape to redistribute light passing through the substrate toward a direction normal to the substrate, at least some of the optical elements comprising non-prismatic elements having at least one curved surface and at least one planar surface for redistributing light along two different axes.

7. A light redirecting film comprising a thin optically transparent substrate having individual optical elements of well defined shape to redistribute light passing through the substrate toward a direction normal to the substrate, at least some of the optical elements having only two surfaces, one of which is curved and the other of which is planar for redirecting light along two different axes.

8. A light redirecting film comprising a thin optically transparent substrate having individual optical elements of well defined shape to redistribute light passing through the substrate toward a direction normal to the substrate, at least some of the optical elements having a total of three surfaces, at least one of the surfaces being curved and at least one other of the surfaces being planar for redirecting light along two different axes.

9. A light redirecting film comprising a thin optically transparent substrate having individual optical elements of well defined shape to redistribute light passing through the substrate toward a direction normal to the substrate, at least some of the optical elements varying in at least one of the following characteristics:

slope angle, density, position, orientation, height or depth, shape, and size, to tailor the film to the light ray output distribution of different backlights.

10. The film of

claim 9

wherein at least some of the optical elements vary in a predetermined pattern to redistribute light within a desired optical distribution.

11. The film of

claim 9

wherein at least some of the optical elements are of a different type.

12. The film of

claim 9

wherein at least some of the optical elements have at least one curved surface.

13. The film of

claim 9

wherein at least some of the optical elements have at least one curved surface and at least one flat surface.

14. The film of

claim 9

wherein at least some of the optical elements are randomly distributed across the substrate.

15. The film of

claim 9

wherein at least some of the optical elements have only one surface which is curved and angled to intersect the substrate.

16. The film of

claim 15

wherein at least some of the optical elements are in the shape of a cone.

17. The film of

claim 15

wherein at least some of the optical elements have a semispherical shape.

18. A light redirecting film comprising a thin optically transparent substrate having a radial type pattern of optical elements to redistribute light passing through the substrate toward a direction normal to the substrate.

19. The film of

claim 18

wherein the optical elements are curved along their length.

20. A light redirecting film comprising a thin optically transparent substrate having a pattern of individual optical elements of well defined shape to redistribute light passing through the substrate toward a direction normal to the substrate, at least some of the optical elements being arranged in groupings across the substrate, at least some of the optical elements in each of the groupings varying in at least one of the following characteristics that collectively produce an average characteristic for each of the groupings:

size, shape, position, depth or height, slope angle, orientation, and density.

21. The film of

claim 20

wherein the average characteristic for each of the groupings varies across the substrate.

22. A light redirecting film comprising a thin optically transparent substrate having a pattern of individual optical elements of well defined shape to redistribute light passing through the substrate toward a direction normal to the substrate, at least some of the optical elements having at least two different shaped surface perimeters.

23. The film of

claim 22

wherein all of the different shaped surface perimeters are planar.

24. The film of

claim 22

wherein one of the different shaped surface perimeters is curved.

25. The film of

claim 22

wherein at least one of the different shaped surface perimeters is planar and at least an other of the different shaped surface perimeters is curved.

26. The film of

claim 22

wherein at least some of the optical elements are oriented at different angles across the film.

27. The film of

claim 22

wherein at least some of the optical elements overlap each other.

28. The film of

claim 27

wherein at least some of the optical elements intersect each other.

29. The film of

claim 27

wherein at least some of the optical elements interlock each other.

30. The film of

claim 27

wherein at least some of the optical elements are staggered with respect to each other.

31. The film of

claim 22

wherein the size of at least some of the optical elements varies across the film.

32. The film of

claim 22

wherein the density of at least some of the optical elements varies across the film.

33. The film of

claim 22

wherein at least some of the optical elements have a total of two surfaces, both of which are angled.

34. The film of

claim 33

wherein one of the angled surfaces is flat and the other of the angled surfaces is curved.

35. The film of

claim 22

wherein at least some of the optical elements have a pair of oppositely angled sides and a pair of oppositely curved ends.

36. The film of

claim 35

wherein the oppositely angled sides intersect each other.

37. The film of

claim 35

wherein at least some of the optical elements have a curved top intersecting the oppositely angled sides and oppositely curved ends.

38. The film of

claim 22

wherein at least some of the optical elements have an angled surface that varies in area across the film.

39. The film of

claim 22

wherein at least some of the optical elements have a uniform depth or height.

40. The film of

claim 22

wherein at least some of the optical elements vary in depth or height across the film.

41. The film of

claim 22

wherein at least some of the optical elements vary in density across the film.

42. The film of

claim 22

wherein at least some of the optical elements vary in size across the film.

43. The film of

claim 22

wherein the orientation of at least some of the optical elements varies across the film.

44. The film of

claim 22

wherein at least some of the optical elements have angled surfaces that intersect the substrate at different angles.

45. The film of

claim 22

wherein at least some of the optical elements have angled surfaces that vary in height or depth across the film.

46. The film of

claim 22

wherein at least some of the optical elements are arranged in groupings across the film, at least some of the optical elements in each of the groupings having at least one different shape characteristic that collectively produces an average shape characteristic for each of the groupings.

47. The film of

claim 46

wherein the average shape characteristic of at least some of the groupings varies across the film.

48. The film of

claim 46

wherein at least some of the optical elements in each of the groupings have a different depth or height that collectively produce an average depth or height characteristic for each of the groupings.

49. The film of

claim 48

wherein the average depth or height characteristic for at least some of the groupings varies across the film.

50. The film of

claim 46

wherein at least some of the optical elements in each of the groupings have a different slope angle that collectively produce an average slope angle for each of the groupings.

51. The film of

claim 50

wherein the average slope angle for each of the groupings varies across the film.

52. The film of

claim 46

wherein at least some of the optical elements in each of the groupings have a different orientation that collectively produce an average orientation for each of the groupings.

53. The film of

claim 52

wherein the average orientation for at least some of the groupings varies across the film.

54. The film of

claim 52

wherein at least some of the optical elements in each of the groupings have at least one sloping surface that is planar.

55. The film of

claim 46

wherein at least some of the optical elements in each of the groupings have a different width or length that collectively produce an average width or length for each of the groupings.

56. The film of

claim 55

wherein the average width or length for at least some of the groupings varies across the film.

57. The film of

claim 22

wherein the optical elements comprise depressions in or projections on the substrate.

58. The film of

claim 22

wherein at least some of the optical elements are oriented at different angles across the substrate for redirecting light along different axes.

59. The film of

claim 22

wherein at least some of the optical elements include a combination of planar and curved surfaces that redirect the light along different axes.

60. The film of

claim 59

wherein the ratio of the areas of the planar and curved surfaces is selected to produce a desired viewing angle.

61. The film of

claim 22

wherein at least some of the optical elements include a combination of planar and curved surfaces, with the curved surfaces oriented to redirect a portion of the light in a plane parallel to the planar surfaces.

62. The film of

claim 22

wherein the substrate has a light entrance surface that is smooth.

63. The film of

claim 22

wherein the substrate has a light entrance surface coated with an optical coating.

64. The film of

claim 22

wherein the substrate has a light entrance surface with a matte or texture finish.

65. The film of

claim 22

wherein the individual optical elements are on opposite sides of the substrate.

66. A light redirecting film comprising a thin optically transparent substrate having a light entrance surface for receiving light from a backlight, and a light exit surface having a pattern of individual optical elements of well defined shape, at least some of the optical elements being of a size that is quite small in comparison to the width and length of the substrate and differing in size or shape to redistribute more of the light emitted by a backlight.

67. The film of

claim 66

wherein at lest some of the optical elements are oriented at different angles relative to each other to redistribute more of the light emitted by a backlight within a desired viewing angle.

68. A light redirecting film system comprising a backlight having a light emitting panel member including at least one input edge for receiving light from a light source, and at least one panel surface for emitting light, and a light redirecting film in close proximity to the panel surface for receiving light emitted by the panel surface, said light redirecting film having a pattern of individual optical elements of well defined shape to redistribute the light emitted by the panel surface toward a direction normal to the film, the size or shape of the optical elements being tailored to redistribute more of the light emitted by the panel surface within a desired viewing angle.

69. The system of

claim 68

wherein at least some of the optical elements are oriented at different angles.

70. The system of

claim 68

wherein at least some of the optical elements have different slope angles.

71. The system of

claim 68

wherein at least some of the optical elements include a combination of planar and curved surfaces.

72. The system of

claim 71

wherein the ratio of the areas of the planar and curved surfaces is selected to produce a desired viewing angle.

73. The system of

claim 68

wherein at least some of the optical elements are oriented at different angles across the film to redistribute the light along two different axes.

74. The system of

claim 68

wherein at least some of the optical elements overlap each other.

75. The system of

claim 74

wherein at least some of the optical elements intersect each other.

76. The system of

claim 74

wherein at least some of the optical elements interlock each other.

77. The system of

claim 74

wherein at least some of the optical elements are staggered with respect to each other.

78. The system of

claim 68

wherein the size of at least some of the optical elements varies across the film.

79. The system of

claim 68

wherein the density of the optical elements varies across the film.

80. The system of

claim 68

wherein at least some of the optical elements are arranged in groupings across the film, at least some of the optical elements in each of the groupings having a different size or shape characteristic that collectively produce an average size or shape characteristic for each of the groupings.

81. The system of

claim 80

wherein at least some of the optical elements in each of the groupings have a different depth or height that collectively produce an average depth or height characteristic for each of the groupings.

82. The system of

claim 80

wherein at least some of the optical elements in each of the groupings have a different slope that collectively produce an average slope characteristic for each of the groupings.

83. The system of

claim 80

wherein at least some of the optical elements in each of the groupings have a different orientation that collectively produce an average orientation characteristic for each of the groupings.

84. The system of

claim 80

wherein at least some of the optical elements in each of the groupings have a different width or length that collectively produce an average width or length characteristic for each of the groupings.

85. The system of

claim 80

wherein the optical elements comprise depressions in or projections on the film.

86. The system of

claim 68

wherein the panel member has a pattern of individual optical deformities that produce a light ray output distribution that varies at different locations on the panel surface.

87. The system of

claim 86

wherein at least some of the deformities of the panel member have a sloping surface that is oriented to face an optically coupled area of the input edge across the panel member.

88. The system of

claim 86

wherein the area of the sloping surface of at least some of the deformities of the panel member varies across the panel member to attain a desired light output distribution from the panel surface.

89. The system of

claim 86

wherein at least some of the deformities of the panel member are arranged in groupings across the panel member, with at least some of the deformities in each of the groupings having a different size or shape characteristic that collectively produce an average size or shape characteristic for each of the groupings.

90. The system of

claim 89

wherein at least some of the deformities in each of the groupings have a different depth or height that collectively produce an average depth or height characteristic for each of the groupings.

91. The system of

claim 89

wherein at least some of the deformities in each of the groupings have a different slope angle that collectively produce an average slope angle characteristic for each of the groupings.

92. The system of

claim 89

wherein at least some of the deformities in each of the groupings have a different orientation that collectively produce an average orientation characteristic for each of the groupings.

93. The system of

claim 89

wherein at least some of the deformities in each of the groupings have a different width or length that collectively produce an average width or length characteristic for each of the groupings.

94. The system of

claim 68

further comprising at least one light source optically coupled to the input edge, the deformities of the panel member being arranged in rows extending radially relative to an area of the input edge to which the light source is optically coupled.

95. The system of

claim 87

wherein at least some of the deformities of the panel member have at least one additional surface for reflecting or refracting light impinging on the additional surface in different directions to spread light across the panel surface to provide a more uniform distribution of light emitted by the panel surface.

96. The system of

claim 89

wherein the sloping surface is planar and the additional surface is curved.

97. A light redirecting film system comprising a backlight having deformities that cause light to be emitted in a predetermined light array output distribution from the backlight, and a light redirecting film in close proximity to the backlight, the film having individual optical elements that work in conjunction with the deformities of the backlight to produce an optimized output light ray angle distribution from the system.

98. A light redirecting film system comprising a backlight including a panel surface having a light ray output distribution that varies at different locations on the panel surface, and a light redirecting film in close proximity to the panel surface, the light redirecting film having a pattern of optical elements that varies at different locations on the film to redistribute the light ray output distribution from the different locations on the panel surface toward a direction normal to the film.

99. The system of

claim 98

further comprising a liquid crystal display in close proximity to the film, the variations in the pattern of optical elements on the film causing a change in the angle of the light ray output distribution from the panel surface to make the light ray output distribution more acceptable to travel through the liquid crystal display.

100. The system of

claim 98

wherein at least some of the optical elements have at least two different shaped surface perimeters.

101. The system of

claim 98

wherein the optical elements comprise at least one of the following:

V grooves, prismatic grooves, and lenticular grooves.

102. The system of

claim 100

wherein the one different shaped surfaces is planar.

103. The system of

claim 102

wherein the other of the different shaped surfaces is curved.

104. The system of

claim 98

wherein at least some of the optical elements overlap each other.

105. The system of

claim 104

wherein at least some of the optical elements intersect each other.

106. The system of

claim 104

wherein at least some of the optical elements interlock each other.

107. The system of

claim 104

wherein at least some of the optical elements are staggered with respect to each other.

108. The system of

claim 98

wherein at least some of the optical elements are oriented at different angles for redirecting light along two different axes.

109. The system of

claim 98

wherein the size of at least some of the optical elements varies across the film.

110. The system of

claim 98

wherein the shape of at least some of the optical elements varies across the film.

111. The system of

claim 98

wherein the height or depth of at least some of the optical elements varies across the film.

112. The system of

claim 98

wherein the position of at least some of the optical elements varies across the film.

113. The system of

claim 98

wherein the density of the optical elements varies across the film.

114. The system of

claim 98

wherein the optical elements are arranged in a pattern that is tailored to redistribute the light ray output distribution of a backlight that receives light from one cold cathode fluorescent light bulb toward a direction normal to the film.

115. The system of

claim 98

wherein the optical elements are arranged in a pattern that is tailored to redistribute the light ray output distribution of a backlight that receives light from two or more cold cathode fluorescent light bulbs toward a direction normal to the film.

116. The system of

claim 98

wherein the optical elements are arranged in a pattern that is tailored to redistribute the light ray output distribution of a backlight that receives light from a single light emitting diode.

117. The system of

claim 98

wherein the optical elements are arranged in a pattern that is tailored to redistribute the light ray output distribution of a backlight that receives light from a plurality of light emitting diodes.

118. The system of

claim 98

wherein the optical elements are arranged in a pattern that is tailored to redistribute the light ray output distribution of a backlight that receives light from perimeter lighting.

119. The system of

claim 98

wherein the optical elements are arranged in a radial type pattern that is tailored to redistribute the light ray output distribution of a backlight that is corner lit.

120. The system of

claim 98

wherein the optical elements are arranged in a radial type pattern that is tailored to redistribute the light ray output distribution of a backlight that is lighted by a single focused light source.

121. The system of

claim 120

wherein the light source is a light emitting diode.

122. A reflective liquid crystal display and a light redirecting film in close proximity to the reflective liquid crystal display, the light redirecting film having a pattern of individual optical elements of well defined shape to increase the brightness of the reflective liquid crystal display, at least some of the optical elements varying in at least one of the following characteristics:

size, shape, position, slope angle, height or depth, pattern, orientation and density.

123. A transflective liquid crystal display and a light redirecting film in close proximity to the transflective liquid crystal display, the light redirecting film having a pattern of individual optical elements of well defined shape to increase the brightness of the transflective liquid crystal display, at least some of the optical elements varying in at least one of the following characteristics:

size, shape, position, slope angle, height or depth, pattern, orientation and density.

124. A method of selecting a light redirecting film for a particular application comprising the steps of providing a length of the film having a repeating pattern of optical deformities that varies along the length of the pattern, selecting an area of the pattern that best suits a particular application, and removing the selected area from the length of film.

125. The method of

claim 124

wherein the selected area is die cut from the length of film.

126. The system of

claim 124

wherein the length of film comprises a roll of the film from which the selected area is removed.

127. A method of selecting a light redirecting film for a particular application comprising the steps of providing a length of the film having a pattern of optical deformities that varies along the length of the pattern, selecting an area of the pattern that best suits a particular application, and removing the selected area from the length of film.