Differentially-cured materials and process for forming same

• US 20040190102A1
• Filed: 12/23/2003
• Published: 09/30/2004
• Est. Priority Date: 08/18/2000
• Status: Abandoned Application

• Current Assignee: Reflexite
• Original Assignee: Reflexite
• Inventors: Mullen, Patrick W., Nilsen, Robert B.
• Application Number:
  US10/744,916
• Publication Number:
  US 20040190102A1
• Time in Patent Office: Days
• US Class Current: 359/237
• CPC Class Codes: B29C 2035/0827 using UV radiation
• CPC Class Codes: B29C 35/08 by wave energy or particle radiation B29C64/00, B29C71/04 take precedence
• CPC Class Codes: B29C 35/0894 provided with masks or diaphragms
• CPC Class Codes: B29C 35/10 for articles of indefinite length
• CPC Class Codes: B29D 11/00 Producing optical elements, e.g. lenses or prisms grinding or polishing of optical elements B24B; constructional form of optical elements G02B; optical parts of spectacles G02C7/00
• CPC Class Codes: B29D 11/00605 Production of reflex reflectors
• CPC Class Codes: B29K 2105/243 Partially cured
• CPC Class Codes: B29K 2995/003 Reflective
• CPC Class Codes: B29L 2011/0083 Reflectors
• CPC Class Codes: B42D 25/324 Reliefs
• CPC Class Codes: G02B 5/045 Prism arrays
• CPC Class Codes: G02B 5/12 Reflex reflectors
• CPC Class Codes: G02B 5/124 plural reflecting elements forming part of a unitary plate or sheet
• CPC Class Codes: G03F 7/001 Phase modulating patterns, e.g. refractive index patterns

Abstract

An optical structure and method for forming same includes a plurality of first cured portions and a plurality of second cured portions that are formed from a same light-curable material. The first plurality of cured portions is cured to a first amount. The plurality of second cured portions is cured to a second amount. The first amount is sufficiently different than the second amount to result with discontinuities on the surface of the structure. The lenticular layer can include a prism layer having random discontinuities on the peaks. The discontinuities can also be formed on a window side of the prisms.

Claims

1. A structure comprising a microstructured layer that includes a plurality of first cured portions and a plurality of second cured portions that are formed from a same radiation-curable material, the first plurality of cured portions being cured to a first amount of time or at a first rate and the plurality of second cured portions being cured to a second amount of time or at a second rate, the first amount of time or rate being sufficiently different than the second amount of time or rate to result with discontinuities on and/or within the surface of the structure.

2. The structure of claim 1, wherein the microstructured layer includes linear prisms, prisms, pyramids, truncated pyramids, lenticulars, cones, moth-eye structured surfaces, diffractive structures, diffractive structured surfaces, textured surfaces, lenses, and/or lens arrays.

3. The structure of claim 2, wherein each microstructured layer includes microstructures that include at least a first side and a second side that meet at a peak, the discontinuities being formed at least partly on peaks of the microstructures.

4. The structure of claim 3, wherein the discontinuities are randomly and/or regularly formed on and/or within the sides and peaks of the microstructures.

5. The structure of claim 1, wherein the discontinuities cause a contour of a surface of the microstructured layer to change shape.

6. The structure of claim 2, wherein each microstructure includes three or more sides, or has a continuous side.

7. The structure of claim 2, wherein the microstructures have a series of base planes and a series of plateaus at a window side of the microstructures, the base planes and the plateaus running along a first axis, the plateaus and base planes alternating along a second axis, the plateaus not being coplanar with the base planes.

8. The structure of claim 1, wherein the discontinuities are formed on and/or within a window side of the microstructured layer.

9. The structure of claim 8, wherein the discontinuities include a random pattern.

10. The structure of claim 8, wherein the discontinuities include a substantially uniform pattern.

11. The structure of claim 2, wherein the microstructured layer includes a plurality of microstructures, further comprising a grooved structure on a window side of microstructures, the discontinuities being formed on and/or within the grooved structure.

12. The structure of claim 2, wherein the discontinuities include randomly spaced circular depressions.

13. The structure of claim 12, wherein the depressions are spaced away from each other a minimum distance.

14. The structure of claim 1, wherein the first amount of time or rate is sufficiently different than the second amount of time or rate to result in a difference in the thickness of the first portion and the thickness of the second portion that is in a range of between about 0.03 and 2.0 micrometers.

15. The structure of claim 1, wherein the radiation-curable material is selected from a group consisting of polyesters, urethanes, epoxy acrylates, and methacrylates.

16. The structure of claim 1, wherein the base is formed from a material selected from the group comprising at least one of polyesters, polyureas, polycarbonates, polyurethanes, acrylics, and polyvinyl chlorides, or a combination thereof.

17. The structure of claim 1, wherein the first plurality of cured portions is configured to represent a logo, geometric forms, or alphanumerics.

18. The structure of claim 1, wherein the first plurality of cured portions has an index of refraction that is different than the index of refraction of the second plurality of cured portions.

19. The structure of claim 1, wherein the first plurality of cured portions has a density that is different than the density of the second plurality of cured portions.

20. The structure of claim 1, wherein the base and the layer include the same radiation-curable material.

21. A method for forming a pattern in a radiation-curable material, comprising:

a) providing between a radiation source and the radiation-curable material, a blocking pattern that can block a portion of the radiation from the radiation source; and

b) curing the material with radiation from the radiation source through the blocking pattern to form a pattern in the radiation-curable material, the radiation-curable material forming a plurality of microstructures on a first side thereof.

22. The method of claim 21, wherein the microstructures include at least a first side and a second side that meet at peaks, the pattern being formed in the first and second sides of the microstructures.

23. The method of claim 22, wherein the pattern includes a plurality of random depressions in the first and second sides of the microstructures.

24. The method of claim 21, wherein the pattern is formed on a window side of microstructures.

25. The method of claim 22, wherein the pattern includes a uniform pattern26.A structure formed by the method of claim 21.

26. A structure formed by the method of claim 21.

27. A pattern transfer structure for forming a differentially-cured pattern in a light-redirecting film that includes a plurality of microstructures, comprising:

a) a radiation source for emitting radiation;

b) a radiation-curable material that forms the film that can be cured by the radiation; and

c) a pattern for blocking a portion of the radiation, the pattern disposed between the radiation source and the radiation-curable material during the curing of the material such that the differentially-cured pattern is formed in the material.

28. The pattern transfer structure of claim 27, further comprising a microstructure pattern provided on a window side of the microstructures.

29. The pattern transfer structure of claim 27, wherein the differentially-cured pattern is random and is formed in sides of the microstructures.

30. The pattern transfer structure of claim 27, wherein the pattern is a uniform pattern formed on a window side of the microstructures.

31. The pattern transfer structure of claim 30, wherein the window side includes a grooved structure.

32. The pattern transfer structure of claim 27, wherein the microstructures include linear prisms, prisms, pyramids, truncated pyramids, lenticulars, cones, moth-eye structured surfaces, diffractive structures, diffractive structured surfaces, textured surfaces, lenses, and/or lens arrays.

33. A method for forming a light-redirecting film comprising:

a) providing a microstructured mold;

b) placing a radiation-curable material in the mold;

c) providing a base film or sheet to carry a formed microstructure formed by the prism mold;

d) providing between a radiation source and the radiation-curable material, a pattern that can block a portion of the radiation-curable material; and

e) curing the radiation-curable material with radiation from the radiation source to form a pattern in the radiation-curable material, the pattern being formed on a structured side of the microstructure or an opposing side of the microstructure.

34. The method of claim 33, wherein the structured side includes a plurality of linear prisms.

35. The method of claim 33, wherein the opposing side includes a grooved structure.

36. An optical film comprising a first side and a second side, the first side including a plurality of linear prisms having a plurality of differentially-cured patterns formed therein.

37. The optical film of claim 36, wherein the second side includes a plurality of differentially-cured patterns formed therein.

38. The optical film of claim 37, wherein the plurality of differentially-cured patterns formed in the second side includes a uniform pattern.

39. The optical film of claim 36, wherein the plurality of linear prisms has a plurality of randomly spaced differentially-cured patterns formed therein.

40. The optical film of claim 39, wherein the randomly spaced differentially-cured patterns include dots.

41. The optical film of claim 40, wherein the dots are spaced a minimum distance away from one another.

42. The optical film of claim 36, wherein the optical film is structured to redirect light entering the second side in a collimating fashion.

43. The optical film of claim 36, wherein the second side includes a series of stepped plateaus and a series of base planes that run along a first axis, wherein the plateaus and base planes alternate along a second axis and the plateaus are not coplanar with the base planes.

44. The optical film of claim 43, wherein differentially-cured patterns are formed at least in the stepped plateaus.

45. An optical structure, comprising:

a first optical film having a plurality of microstructures, at least some of the microstructures including a plurality of differentially-cured random and/or regular patterns formed therein; and

a second optical film having a plurality of microstructures on a first side, and a plurality of differentially-cured random and/or regular patterns formed in a second side.

46. The optical structure of claim 45, wherein the microstructures of the first optical film face the second side of the second optical film.

47. The optical structure of claim 45, wherein the microstructures of the first optical film are disposed on a first side thereof, further comprising differentially-cured random and/or regular patterns formed in a second side of the first optical film.

48. The optical structure of claim 45, further comprising differentially-cured random and/or regular patterns formed in the microstructures of the second optical film.

49. The optical structure of claim 45, wherein the first optical film includes a plurality of microstructures on a second side of the first optical film.

50. The optical structure of claim 45, wherein the second optical film includes a plurality of microstructures on the second side of the second optical film.

51. The optical structure of claim 45, further comprising a random and/or regular pattern formed on a second side of the first film.

52. The optical structure of claim 45, wherein the plurality of differentially-cured patterns formed in the second side of the second optical film is formed in a grooved structure.

53. The optical structure of claim 45, wherein the plurality of microstructures of the first optical film is disposed on a first side, further comprising a plurality of moth-eye structures on a second side of the first optical film.

54. The optical structure of claim 53, wherein the second side of the first optical film includes a grooved structure.

55. The optical structure of claim 45, wherein the microstructures of the first and second film include linear prisms that are oriented at about ninety degrees relative to one another.

56. An optical film comprising a plurality of randomly positioned areas that are formed from a radiation-curable material cured to a first amount of time or rate, remaining areas of the optical film being formed from the same radiation-curable material but cured to a second amount of time or rate.

57. The optical film of claim 56, wherein the optical film includes linear prisms on a first side.

58. The optical film of claim 57, further comprising a plurality of moth-eye structures on a second side.

59. The optical film of claim 56, wherein the optical film includes a series of stepped plateaus and a series of base planes that run along a first axis, wherein the plateaus and base planes alternate along a second axis and the plateaus are not coplanar with the base planes.

60. A mask for forming a differentially-cured surface on an optical film comprising a plurality of at least partially opaque areas provided on a transparent layer, the opaque areas being distributed on the transparent layer according to a desired coverage percentage of the opaque areas on the transparent layer, the opaque areas being at least partially opaque to at least one curing wavelength of radiation used to cure a radiation-curable material.

61. The mask of claim 60, wherein the opaque areas include alphanumerics or geometric patterns having line widths of about fifty to 500 micrometers.

62. The mask of claim 60, wherein a minimum width halo surrounds each opaque area to prevent adjacent opaque areas from being contiguously located on the transparent layer.

63. The mask of claim 60, wherein the opaque areas are randomly distributed on the transparent layer.

64. The mask of claim 60, wherein the opaque areas are substantially circular.

65. The mask of claim 64, wherein the opaque areas have a diameter of about 152 micrometers.

66. An optical structure, comprising:

an optical film having a plurality of linear prisms, each linear prism including at least a first side and a second side terminating at a peak; and

a plurality of randomly positioned depressions in the linear peaks, in the sides, or a combination thereof.

67. The optical structure of claim 66, wherein the prisms are disposed on a first side of the film, further comprising a plurality of randomly positioned depressions disposed in a second side of the film.

68. The optical structure of claim 66, wherein the prisms are disposed on a first side of the film, further comprising a grooved structure on a second side of the film.

69. An optical film comprising a plurality of linear prisms on a first side of the film, and a substantially planar surface on a second side of the film, at least the first side or the second side including depressed areas formed by a differentially-curing process.

70. The optical film of claim 69, wherein the depressed areas are randomly positioned.

71. The optical film of claim 69, wherein the depressed areas are in the form of a logo, geometric form, or alphanumerics.

72. A backlighting system comprising:

a light source;

a first light-redirecting film that includes a plurality of linear prisms, the prisms including a differentially-cured pattern therein;

a second light-redirecting film that includes a plurality of linear prisms on a first side and a differentially-cured pattern formed in a second side that faces the linear prisms of the first light-redirecting film; and

a waveguide for receiving light from the light source and redirecting the light toward the first light-redirecting film.

73. The backlighting system of claim 72, further comprising a grooved structure on a side of the first light-redirecting film opposing the linear prisms thereof.

74. The backlighting system of claim 72, further comprising a grooved structure on the second side of the second light-redirecting film.

75. An optical structure comprising a microstructured layer provided on a non-smooth surface.

76. The optical structure of claim 75, wherein the non-smooth surface includes an undulating pattern.

77. The optical structure of claim 75, wherein the microstructured layer includes a moth-eye structure formed on an excess resin layer on a substrate film, the excess resin layer being differentially-cured to form the non-smooth surface.

78. A method for forming a microstructured layer provided on a non-smooth surface, comprising:

dispensing a resin layer between a substrate film and tool used to form a microstructured surface in the resin layer; and

curing the resin layer through a mask to form a differentially-cured structure that is non-smooth, the microstructured layer being formed on the non-smooth surface.