Optical substrate and method of making

• US 20050225865A1
• Filed: 12/23/2004
• Published: 10/13/2005
• Est. Priority Date: 05/20/2002
• Status: Active Grant

• Current Assignee: SABIC Global Technologies BV (Government of Saudi Arabia)
• Original Assignee: General Electric Company
• Inventors: Olczak, Eugene
• Granted Patent: US 7,180,672 B2
• Time in Patent Office: Days
• US Class Current: 359/619
• CPC Class Codes: G02B 5/0221 the surface having an irregular structure G02B5/0226 takes precedence
• CPC Class Codes: G02B 5/0226 having particles on the surface
• CPC Class Codes: G02B 5/0231 the surface having microprismatic or micropyramidal shape macroscopic prism arrays G02B5/045
• CPC Class Codes: G02B 5/0242 by means of dispersed particles
• CPC Class Codes: G02B 5/0278 used in transmission
• CPC Class Codes: G02B 5/045 Prism arrays
• CPC Class Codes: G02B 6/0051 Diffusing sheet or layer
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer

Abstract

An optical surface substrate. The optical substrate features a three-dimensional surface. The optical substrate is defined by a first surface structure function modulated by a second surface structure function, the first surface structure function producing at least one specular component from a first input beam of light. The second surface structure function has a geometry with at least pseudo-random characteristics to modulate the first surface structure function such that the surface of the optical substrate produces specular and diffuse light from the first input beam of light. The optical substrate is suitable for use in a variety of applications, including brightness enhancement and projection devices.

Claims

1. An optical substrate, comprising:

a surface characterized by a correlation function value of less than about 37 percent of an initial value within a correlation length of about 1 cm or less, wherein the surface is defined by a first surface structure function modulated by a second surface structure function, the surface of the optical substrate producing specular and diffuse light from a first input beam of light.

2. The optical substrate as set forth in claim 1, wherein the first surface structure function extends a length from a first end to a second end of the substrate.

3. The optical substrate as set forth in claim 2, wherein the first surface structure function has a sawtooth or triangular cross section.

4. The optical substrate as set forth in claim 1, wherein the surface of the optical substrate comprises a shape that turns and diffuses light to form a plurality of diffusion ellipses each with a power half angle between about 0.1 and about 60 degrees.

5. The optical substrate as set forth in claim 4, wherein the power half angle is between about 1 and about 5 degrees.

6. The optical substrate as set forth in claim 4, wherein a first input beam of light has a first angle of incidence and the surface of the optical substrate is shaped so that the first input beam of light is transmitted through the optical substrate and turned by the surface of the optical substrate to an output angle different from the first angle of incidence.

7. The optical substrate as set forth in claim 6, wherein the output angles of the specular components are determined by the first surface structure function.

8. The optical substrate as set forth in claim 7, wherein a second input beam of light normal to the optical substrate is substantially reflected by the surface of the optical substrate and forms output specular components with a power half angle between about 0.1 and about 60 degrees.

9. The optical substrate as set forth in claim 8, wherein the correlation length is about 200 microns or less.

31. The optical substrate as set forth in claim 1 wherein the first surface function is a triangle with a width of approximately 40 μ

m and a height of between 1 μ

m and 200 μ

m.

32. The optical substrate as set forth in claim 1 wherein the first surface function is a triangle with a width of approximately 40 μ

m and a height of approximately 18 μ

m.

33. The optical substrate as set forth in claim 1 wherein the first surface function is a triangle with a base to height ratio of between 40 to 1 and 1 to 10.

34. The optical substrate as set forth in claim 1 wherein the first surface function is a triangle with a base to height ratio approximately 40 to 18.

35. The optical substrate as set forth in claim 1 wherein the surface of the optical substrate is formed with an optically transparent material with an index of refraction of between 1.1 and 3.0.

36. The optical substrate as set forth in claim 1 wherein the surface of the optical substrate is formed with an optically transparent material with an index of refraction of approximately 1.75.

37. The optical substrate as set forth in claim 32 wherein the surface of the optical substrate is formed with an optically transparent material with an index of refraction of approximately 1.75.

42. The optical substrate as set forth in claim 1, wherein the second surface structure function has a geometry with at least pseudo-random characteristics to modulate the first surface structure function in one or more of frequency and peak angle along the length of the first surface structure function.

10. A brightness enhancement film, comprising:

a surface characterized by a correlation length of about 1 cm or less, the surface having a shape to turn and diffuse incident light to produce at least a 30 percent brightness increase on-axis to a viewer, wherein the surface produces diffused components of light with a power half angle between about 0.1 and 60 degrees

11. The film as set forth in claim 10, wherein the surface is characterized by a correlation length of about 200 microns or less.

12. The film as set forth in claim 10, wherein the brightness increase on-axis is about 30 percent to about 300 percent.

13. The film as set forth in claim 10, wherein the brightness increase on-axis is about 50 percent to about 200 percent.

43. The brightness enhancement film as set forth in claim 10, wherein the second surface structure function has a geometry with at least pseudo-random characteristics to modulate the first surface structure function in one or more of frequency and peak angle along the length of the first surface structure function.

14. An optical substrate, comprising:

a three-dimensional surface defined by a first surface structure function and a second surface structure function, the first surface structure function having a geometry with optical characteristics to produce at least one output specular component from an input beam of light;

the second surface structure function having a geometry with at least pseudo-random characteristics to modulate the first surface structure function;

wherein the three-dimensional surface has a correlation function value of less than about 37 percent of an initial correlation function value in a correlation length of about 1 cm or less.

15. The optical substrate as set forth in claim 14, wherein the surface is characterized by a correlation length of about 200 microns or less.

16. The optical substrate as set forth in claim 14, wherein the first surface structure function is characterized by a series of first surface structure functions, each first surface structure function having a length, width and peak angle.

17. The optical substrate as set forth in claim 14, wherein the surface diffuses and turns the input beam of light to form a plurality of diffusion ellipses each with a power half angle between about 0.1 and about 60 degrees.

18. The optical substrate as set forth in claim 17, wherein the power half angle is between about 1 and about 5 degrees.

19. The optical substrate as set forth in claim 17, wherein the input beam of light has an angle of incidence and the surface is structured so that the input beam of light is transmitted through the optical substrate and turned by the surface to form output angles of the specular components that are different from the angle of incidence.

20. The optical substrate as set forth in claim 19, wherein the output angles of the specular components are determined by the first surface structure function.

44. The optical substrate as set forth in claim 14, wherein the second surface structure function has a geometry with at least pseudo-random characteristics to modulate the first surface structure function in one or more of frequency and peak angle along the length of the first surface structure function.

49. The optical substrate of claim 16, wherein the optical substrate comprises a brightness enhancement film.

21. An optical substrate, comprising:

a surface characterized by a correlation function value of less than about 37 percent of an initial value within a correlation length of about 1 cm or less, wherein the surface is defined by a first surface structure function having a sawtooth or triangular cross section extending a length from a first end to a second end of the substrate modulated by a second function, the surface of the optical substrate producing specular and diffuse light from a first input beam of light.

45. The optical substrate as set forth in claim 21, wherein the second surface structure function has a geometry with at least pseudo-random characteristics to modulate the first surface structure function in one or more of frequency and peak angle along the length of the first surface structure function.

22. A brightness enhancement film, comprising:

a surface characterized by a correlation length of about 1 cm or less, the surface having a shape to turn and diffuse incident light to produce a 50 percent to 200 percent brightness increase on-axis to a viewer, wherein the surface produces diffused components of light with a power half angle between about 0.1 and 60 degrees.

46. The brightness enhancement film as set forth in claim 22, wherein the second surface structure function has a geometry with at least pseudo-random characteristics to modulate the first surface structure function in one or more of frequency and peak angle along the length of the first surface structure function.

23. An optical substrate, comprising:

a three-dimensional surface defined by a first surface structure function and a second surface structure function, the first surface structure function having a length, width and peak angle with optical characteristics to produce at least one output specular component from an input beam of light;

the second surface structure function having a geometry with at least pseudo-random characteristics to modulate the first surface structure function in one or more of frequency, phase and peak angle along the length of the first surface structure function;

wherein the three-dimensional surface has a correlation function value of less than about 37 percent of an initial correlation function value in a correlation length of about 1 cm or less.

47. The optical substrate as set forth in claim 23, wherein the second surface structure function has a geometry with at least pseudo-random characteristics to modulate the first surface structure function in one or more of frequency and peak angle along the length of the first surface structure function.

24. A backlight display device comprising:

an optical source for generating light;

a light guide for guiding the light therealong including a reflective surface for reflecting the light out of the light guide;

at least one optical substrate receptive of the light from the reflective surface, the optical substrate comprising;

a three-dimensional surface defined by a first surface structure function and a second surface structure function,

the first surface structure function having a length, width and peak angle with optical characteristics to produce at least one output specular component from an input beam of light;

the second surface structure function having a geometry with at least pseudo-random characteristics to modulate the first surface structure function in one or more of frequency, phase and peak angle along the length of the first surface structure function, the phase being a horizontal peak position along the width;

wherein the three-dimensional surface has a correlation function value of less than about 37 percent of an initial correlation function value in a correlation length of about 1 cm or less.

25. The backlight display device as set forth in claim 24 wherein the at least one optical substrate comprises a plurality of optical substrates.

26. The backlight display device as set forth in claim 25 wherein the plurality of optical substrates include first and second surface functions in a relative orientation from zero to ninety degrees with respect to one another.

27. The backlight display device as set forth in claim 26 wherein the relative orientation of the first and second surface functions is parallel or perpendicular with respect to one another.

28. A backlight display device comprising:

an optical source for generating light;

a light guide for guiding the light therealong including a reflective surface for reflecting the light out of the light guide; and

an optical substrate receptive of the light from the reflective surface, the optical substrate comprising;

a first three-dimensional surface defined by first and second surface structure functions;

the first surface structure function having a length, width and peak angle with optical characteristics to produce at least one output specular component from an input beam of light;

the second surface structure function having a geometry with at least pseudo-random characteristics to modulate the first surface structure function in one or more of frequency, phase and peak angle along the length of the first surface structure function, the phase being a horizontal peak position along the width of the first surface structure function;

a second three-dimensional surface opposing the first three-dimensional surface and defined by a third surface structure function and a fourth surface structure function;

the third surface structure function having a length, width and peak angle with optical characteristics to produce at least one output specular component from an input beam of light;

the fourth surface structure function having a geometry with at least pseudo-random characteristics to modulate the third surface structure function in one or more of frequency, phase and peak angle along the length of the first surface structure function, the phase being a horizontal peak position along the width of the third surface structure function;

wherein the first and second three-dimensional surfaces have a correlation function value of less than about 37 percent of an initial correlation function value in a correlation length of about 1 cm or less.

29. The backlight display device as set forth in claim 28 wherein the first and second surface structure functions are in a relative orientation from zero to ninety degrees with respect to one another.

30. The backlight display device as set forth in claim 29 wherein the relative orientation of the first and third surface structure functions is parallel or perpendicular with respect to one another.

38. The optical substrate as set forth in claim 28 wherein the second surface is optically smooth or planar.

39. The optical substrate as set forth in claim 28 wherein the second surface has a matte or diffuse finish.

40. The optical substrate as set forth in claim 39 wherein the second surface has diffusion characteristics that are anamorphic or anisotropic.

41. The optical substrate as set forth in claim 28 wherein the second surface is optically smooth or planar including a pattern of protrusions formed either in the substrate or attached with an adhesive.

48. The backlight display device as set forth in claim 28, wherein the second surface structure function has a geometry with at least pseudo-random characteristics to modulate the first surface structure function in one or more of frequency and peak angle along the length of the first surface structure function, and wherein the fourth surface structure function has a geometry with at least pseudo-random characteristics to modulate the third surface structure function in one or more of frequency and peak angle along the length of the third surface structure function.

50. An optical substrate, comprising:

a three-dimensional surface defined by a first surface structure function and a second surface structure function, the first surface structure function having a geometry with optical characteristics to produce at least one output specular component from an input beam of light,

the second surface structure function having a geometry with at least pseudo-random characteristics to modulate the first surface structure function such that the surface of the optical substrate producing specular and diffuse light from the input beam of light, wherein the second surface structure function modulates the first surface structure function in two orthogonal directions.

51. A light display comprising:

a light flux paralizer providing light;

an exit light direction modifier having a light exit surface opposite to the light flux paralizer, and a light incident surface towards the light flux paralizer to receive light from the light flux paralizer,

the light incident surface defined by a first surface structure function and a second surface structure function, the first surface structure function having a geometry with optical characteristics to produce at least one output specular component from the received light, the first surface structure function defining a plurality of prism surfaces,

the second surface structure function having a geometry with at least pseudo-random characteristics to modulate the first surface structure function such that the light incident surface producing specular and diffuse light from the received light.

52. An optical substrate, comprising:

a three-dimensional surface defined by a first surface structure function and a second surface structure function, the first surface structure function having a geometry with optical characteristics to produce at least one output specular component from an input beam of light;

the second surface structure function having a geometry with at least pseudo-random characteristics to modulate the first surface structure function such that the surface of the optical substrate producing specular and diffuse light from the input beam of light,

wherein the first surface structure function is defined as a surface of a plurality of first prisms having a first prism configuration and a plurality of second prisms having a second configuration different from the first prism configuration.

53. An optical substrate, comprising:

a three-dimensional surface defined by a first surface structure function and a second surface structure function, the first surface structure function having a geometry with optical characteristics to produce at least one output specular component from an input beam of light;

the second surface structure function having a geometry with at least pseudo-random characteristics to modulate the first surface structure function such that the surface of the optical substrate producing specular and diffuse light from the input beam of light,

wherein the first surface structure function is defined as a surface having a first region having multiple peaks with a first average peak height, and a second region having multiple peaks with a second average peak height different from the first average peak height.

54. A brightness enhancement film, comprising:

a three-dimensional surface defined by a first surface structure function and a second surface structure function, the first surface structure function having a geometry with optical characteristics to produce at least one output specular component from an input beam of light;

the second surface structure function having a geometry with at least pseudo-random characteristics to modulate the first surface structure function such that the surface of the brightness enhancement film producing specular and diffuse light from the input beam of light,

wherein the first surface structure function is defined as a surface with pairs of side by side prisms, each pair having first and second prisms, and each prism having a prism angle and a valley angle wherein either said prism angle or said valley angle of each pair, but not both, are equal.

55. An optical substrate, comprising:

an anti-wet-out surface; and

a three-dimensional surface opposite the anti-wet-out surface, the three-dimensional surface defined by a first surface structure function and a second surface structure function, the first surface structure function having a geometry with optical characteristics to produce at least one output specular component from an input beam of light,

the second surface structure function having a geometry with at least pseudo-random characteristics to modulate the first surface structure function such that the surface of the optical substrate producing specular and diffuse light from the input beam of light, and

wherein the first surface structure function is defined as a surface with multiple prisms.

56. An optical substrate, comprising:

a three-dimensional surface defined by a first surface structure function and a second surface structure function, the first surface structure function having a geometry with optical characteristics to produce at least one output specular component from an input beam of light;

the second surface structure function having a geometry with at least pseudo-random characteristics to modulate the first surface structure function such that the surface of the optical substrate producing specular and diffuse light from the input beam of light, the first surface structure function defining a plurality of prisms each having a slope wherein the second surface structure function modulates the slope.

57. An optical substrate, comprising:

a three-dimensional surface defined by a first surface structure function and a second surface structure function, the first surface structure function having a geometry with optical characteristics to produce at least one output specular component from an input beam of light,

the second surface structure function having a geometry with at least pseudo-random characteristics to modulate the first surface structure function such that the surface of the optical substrate producing specular and diffuse light from the input beam of light, the first surface structure function defined as a surface of a lenslet array.

58. An optical substrate, comprising:

a three-dimensional surface defined by a first surface structure function and a second surface structure function, the first surface structure function having a geometry with optical characteristics to produce at least one output specular component from an input beam of light;

the second surface structure function having a geometry with at least pseudo-random characteristics to modulate the first surface structure function such that the surface of the optical substrate producing specular and diffuse light from the input beam of light,

wherein the first surface structure function is defined as a surface of a plurality of first prisms, each of the first prisms having a first prism angular orientation, and a plurality of second prisms, each of the second prisms having a second prism angular orientation different from the first prism angular orientation.

59. An optical substrate, comprising:

a three-dimensional surface defined by a first surface structure function and a second surface structure function, the first surface structure function having a geometry with optical characteristics to produce at least one output specular component from an input beam of light,

the second surface structure function having a geometry with at least pseudo-random characteristics to modulate the first surface structure function such that the surface of the optical substrate producing specular and diffuse light from the input beam of light,

wherein the first surface structure function is defined as surface of a plurality of prism structures extending generally in a first direction, having a spacing in a second direction perpendicular to the first direction between adjacent prismatic structures, and having a height varying in the first direction.

60. A display device comprising:

a backlight for providing light; and

an optical film receptive of the light from the backlight, the optical film comprising;

a three-dimensional surface defined by a first surface structure function and a second surface structure function, the first surface structure function having a geometry with optical characteristics to produce at least one output specular component from the light received from the backlight,

the second surface structure function having a geometry with at least pseudo-random characteristics to modulate the first surface structure function such that the surface of the optical substrate producing specular and diffuse light from the light received from the backlight, wherein the optical film includes beads therein to produce diffuse light from the light received from the backlight.

61. An optical substrate, comprising:

an optical film having a three-dimensional surface defined by a first surface structure function and a second surface structure function, the first surface structure function having a geometry with optical characteristics to produce at least one output specular component from an input beam of light,

the second surface structure function having a geometry with at least pseudo-random characteristics to modulate the first surface structure function such that the surface of the optical substrate producing specular and diffuse light from the input beam of light; and

a metal layer on the optical film.

62. An optical substrate, comprising:

a three-dimensional surface defined by a first surface structure function and a second surface structure function, the first surface structure function having a geometry with optical characteristics to produce at least one output specular component from an input beam of light,

the second surface structure function having a geometry with at least pseudo-random characteristics to modulate the first surface structure function such that the surface of the optical substrate producing specular and diffuse light from the input beam of light, wherein the first surface structure function is defined by the surface of a non-ordered arrangement of prisms.

63. An optical substrate, comprising:

a three-dimensional surface defined by a first surface structure function and a second surface structure function, the first surface structure function having a geometry with optical characteristics to produce at least one output specular component from an input beam of light,

the second surface structure function having a geometry with at least pseudo-random characteristics to modulate the first surface structure function such that the surface of the optical substrate producing specular and diffuse light from the input beam of light, wherein the first surface structure function is defined by the surface of a plurality of refraction prisms and a plurality reflection prisms.

64. An optical substrate, comprising:

an optical film comprising;

a first surface having a plurality of randomly oriented bumps, and

a second three-dimensional surface defined by a first surface structure function and a second surface structure function, the first surface structure function having a geometry with optical characteristics to produce at least one output specular component from an input beam of light,

the second surface structure function having a geometry with at least pseudo-random characteristics to modulate the first surface structure function such that the surface of the optical substrate producing specular and diffuse light from the input beam of light, wherein the first surface structure function is defined by the surface of a lens array.

65. A light guide plate, comprising:

a three-dimensional surface defined by a first surface structure function and a second surface structure function, the first surface structure function having a geometry with optical characteristics to produce at least one output specular component from an input beam of light,

the second surface structure function having a geometry with at least pseudo-random characteristics to modulate the first surface structure function such that the surface of the light guide plate producing specular and diffuse light from the input beam of light; and

a surface opposite the three-dimensional surface having a plurality of circular or polygonal dots.

66. A light guide plate, comprising:

a three-dimensional surface defined by a first surface structure function and a second surface structure function, the first surface structure function having a geometry with optical characteristics to produce at least one output specular component from an input beam of light,

the second surface structure function having a geometry with at least pseudo-random characteristics to modulate the first surface structure function such that the surface of the light guide plate producing specular and diffuse light from the input beam of light, wherein the first surface structure function is defined by a surface of a plurality of prisms, the prisms have a curved surface in two orthogonal directions.

67. An optical substrate, comprising:

a three-dimensional surface defined by a first surface structure function and a second surface structure function, the first surface structure function having a geometry with optical characteristics to produce at least one output specular component from an input beam of light,

the second surface structure function having a geometry with at least pseudo-random characteristics to modulate the first surface structure function such that the surface of the optical substrate producing specular and diffuse light from the input beam of light, wherein the first surface structure function is defined by a surface of a plurality of prisms, each prisms having a facet with a curved cross section.

68. A backlight display device comprising:

an optical source for generating light;

a light guide for guiding the light therealong including an exit surface for light exiting out of the light guide;

a turning film having a three dimensional surface receptive of the light from the exit surface, the exit surface facing toward the tuning film, the three-dimensional surface defined by a first surface structure function and a second surface structure function, the first surface structure function having a geometry with optical characteristics to produce at least one output specular component from an input beam of light,

the second surface structure function having a geometry with at least pseudo-random characteristics to modulate the first surface structure function such that the surface of the optical substrate producing specular and diffuse light from the input beam of light, wherein the first surface structure function is defined by a surface of a plurality of prisms.

69. The backlight display device of claim 68 wherein the prisms have a nominal pitch between 50 μ

m and 500 μ

m.

70. The backlight display device of claim 68 wherein the turning film is laminated to a liquid crystal substrate.