Optical substrate and method of making

• US 7,324,284 B2
• Filed: 07/27/2006
• Issued: 01/29/2008
• Est. Priority Date: 05/20/2002
• Status: Expired due to Fees

• Current Assignee: Sabic Innovative Plastics IP BV (Government of Saudi Arabia)
• Original Assignee: General Electric Company
• Inventors: Olczak, Eugene
• Primary Examiner(s): Harrington; Alicia M
• Application Number:
  US11/460,309
• Publication Number:
  US 20060256444A1
• Time in Patent Office: 551 Days
• Field of Search: 359/621
• US Class Current: 359/621
• 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, the first surface structure function defining a plurality of prism structures having a length, width and peak angle with optical characteristics to produce at least one output specular component from an input beam of light, and the second surface structure function having a geometry with at least pseudo-random characteristics to modulate the first surface structure function in at least a phase.

2. The optical substrate as set forth in claim 1, wherein the correlation length is about 200 microns or less.

3. The optical substrate as set forth in claim 1, wherein the second surface structure function comprises a sinusoidal carrier waveform modulated by a random function.

4. The optical substrate as set forth in claim 3, wherein the random function is spatially constant, spatially varying, or a combination of spatially constant and spatially varying.

5. 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, the surface defined by a first surface structure function and a second surface structure function, the first surface structure function defining a plurality of prism structures having a length, width and peak angle with optical characteristics to produce at least one output specular component from an input beam of light, and the second surface structure function having a geometry with at least pseudo-random characteristics to modulate the first surface structure function in at least a phase.

6. The film as set forth in claim 5, wherein the surface is characterized by a correlation length of about 200 microns or less.

7. The film as set forth in claim 5, wherein the second surface structure function comprises a sinusoidal carrier waveform modulated by a random function.

8. The film as set forth in claim 7, wherein the random function is spatially constant, spatially varying, or a combination of spatially constant and spatially varying.

9. 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, the first surface structure function defining a plurality of prism structures having a length, width and peak angle with optical characteristics to produce at least one output specular component from an input beam of light, and the second surface structure function having a geometry with at least pseudo-random characteristics to modulate the first surface structure function in at least a phase.

10. The optical substrate as set forth in claim 9, wherein the surface is characterized by a correlation length of about 200 microns or less.

11. The optical substrate as set forth in claim 9, wherein the second surface structure function comprises a sinusoidal carrier waveform modulated by a random function.

12. The optical substrate as set forth in claim 11, wherein the random function is spatially constant, spatially varying, or a combination of spatially constant and spatially varying.

13. 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, the surface defined by a first surface structure function and a second surface structure function, the first surface structure function defining a plurality of prism structures having a length, width and peak angle with optical characteristics to produce at least one output specular component from an input beam of light, and the second surface structure function having a geometry with at least pseudo-random characteristics to modulate the first surface structure function in at least a phase.

14. The film as set forth in claim 13, wherein the second surface structure function comprises a sinusoidal carrier waveform modulated by a random function.

15. The film as set forth in claim 14, wherein the random function is spatially constant, spatially varying, or a combination of spatially constant and spatially varying.

16. 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

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

a three-dimensional surface defined by two surface structure functions,

the first surface structure function defining a plurality of prism structures 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 at least a phase;

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.

17. The backlight display device as set forth in claim 16, wherein the second surface structure function comprises a sinusoidal carrier waveform modulated by a random function.

18. The backlight display device as set forth in claim 17, wherein the random function is spatially constant, spatially varying, or a combination of spatially constant and spatially varying.

19. An optical substrate, comprising:

a surface 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, the first surface structure function defining at least one prism structure with optical characteristics to produce at least one output specular component from an input beam of light, and the second surface structure function comprising a sinusoidal function and random function to modulate the first surface structure function in at least a phase, the random function being spatially constant, spatially varying, or a combination of spatially constant and spatially varying.

20. An optical substrate, comprising:

a surface defined by a first surface structure function modulated by a second surface structure function, the first surface structure function defining at least one prism structure, and the second surface structure function comprising a sinusoidal function and random function to modulate the first surface structure function in at least a phase, the random function being spatially constant, spatially varying, or a combination of spatially constant and spatially varying.

21. An optical substrate comprising:

an optical 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 and comprising a plurality of sinusoidally modulated prism structures characterized by a plurality of parameters, wherein at least one of the parameters is randomized for at least one of the prism structures.

22. The substrate as set forth in claim 21, wherein the sinusoidally modulated prism structures have a peak position of the prism structures sinusoidally modulated according to a sinusoidal function, and the randomized parameter is an amplitude of the sinusoidal function such that at least one of the sinusoidally modulated prism structures is modulated along a length of the prism structure given as the x direction.

23. The substrate as set forth in claim 21, wherein the sinusoidally modulated prism structures have a peak position of the prism structures sinusoidally modulated according to a sinusoidal function, and the randomized parameter is a frequency of the sinusoidal function such that at least one of the sinusoidally modulated prism structures is modulated along a length of the prism structure given as the x direction.

24. The substrate as set forth in claim 21, wherein the substrate is a brightness enhancement film, and the surface has 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.

25. The substrate as set forth in claim 21, wherein the substrate is a brightness enhancement film, and the surface is 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.

26. 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

at least one optical substrate according to claim 21 receptive of the light from the reflective surface.

27. An optical substrate comprising:

an optical surface comprising a plurality of sinusoidally modulated prism structures characterized by a plurality of parameters, wherein at least one of the parameters is randomized for at least one of the prism structures,

wherein the sinusoidally modulated prism structures have a peak position of the prism structures sinusoidally modulated according to a sinusoidal function, and the randomized parameter is a phase of the sinusoidal function such that at least one of the sinusoidally modulated prism structures is modulated along a length of the prism structure given as the x direction, such that a lateral position of a peak of the prism structure as a function of x is given by sin(x/k+c×

r(x)), where r(x) is the randomized parameter, and k and c are constants.

28. The substrate as set forth in claim 27, where the randomized parameter is constant over the length x for at least one of the prism structures.

29. The substrate as set forth in claim 27 where the randomized parameter is varying over the length x for at least one of the prism structures.

30. An optical substrate comprising:

an optical surface comprising a plurality of sinusoidally modulated prism structures characterized by a plurality of parameters, wherein at least one of the parameters is randomized for at least one of the prism structures,

wherein the sinusoidally modulated prism structures have a peak position of the prism structures sinusoidally modulated according to a sinusoidal function, and the randomized parameter is a phase of the sinusoidal function such that at least one of the sinusoidally modulated prism structures is modulated along a length of the prism structure given as the x direction, such that a lateral position of a peak of the prism structure as a function of x is given by sin(x/(k+c×

r(x))), where r(x) is the randomized parameter, and k and c are constants.

31. The substrate as set forth in claim 30, where the randomized parameter is constant over the length x for at least one of the prism structures.

32. The substrate as set forth in claim 30 where the randomized parameter is varying over the length x for at least one of the prism structures.

33. 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 and defined by a first surface structure function modulated by a second surface structure function, the first surface structure function defining a plurality of prism structures extending along a length and having a height, the second surface structure function having a geometry with at least pseudo-random characteristics to modulate the first surface structure function in the height along the length, and wherein the second surface structure function comprises a sinusoidal carrier waveform modulated by a random function.

34. The substrate as set forth in claim 33, the surface characterized by a correlation function having a correlation length of less than 1 cm.

35. The substrate as set forth in claim 34, the surface characterized by a correlation function having a correlation length of less than 0.5 cm.

36. The substrate as set forth in claim 35, the surface characterized by a correlation function having a correlation length of less than 200 μ

m.

37. An optical substrate, comprising:

a surface defined by a first surface structure function modulated by a second surface structure function, the first surface structure function defining at least one prism structure, and the second surface structure function comprising a random function to modulate the first surface structure function along a length of the prism structure such that a lateral position of a peak of the prism structure and a height of the prism structure are randomly modulated.

38. The substrate as set forth in claim 37, wherein the second surface structure function further comprises a sinusoidal function.

39. 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 and having a plurality of prism structures modulated by a plurality of sinusoidal functions, wherein at least one of the sinusoidal functions has a randomized parameter for at least one of the prism structures.

40. 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 and having a plurality of prism structures modulated by a plurality of functions, wherein at least one of the functions has a randomized parameter for at least one of the prism structures.