Light collimating device

• US 7,480,101 B2
• Filed: 03/14/2007
• Issued: 01/20/2009
• Est. Priority Date: 03/26/2002
• Status: Expired due to Fees

• Current Assignee: Rambus Delaware LLC (Rambus Inc.)
• Original Assignee: Brilliant Film, LLC
• Inventors: Wojeiechowski, Timothy J., Lash, Thomas E., Lubart, Neil D.
• Primary Examiner(s): Harrington; Alicia M
• Application Number:
  US11/686,143
• Publication Number:
  US 20070153396A1
• Time in Patent Office: 678 Days
• Field of Search: 359/641, 359/619, 359/622, 359/708, 359/712, 359/718, 362/551, 362/559
• US Class Current: 359/641
• CPC Class Codes: G02B 17/002 Arrays of reflective systems
• CPC Class Codes: G02B 27/0972 Prisms prisms per se G02B5/04
• CPC Class Codes: G02B 27/0983 being curved
• CPC Class Codes: G02B 27/30 Collimators
• CPC Class Codes: G02F 1/133524 Light-guides, e.g. fibre-optic bundles, louvered or jalousie light-guides
• CPC Class Codes: G02F 1/133555 Transflectors
• CPC Class Codes: G02F 1/133607 the light controlling member including light directing or refracting elements, e.g. prisms or lenses

Abstract

A collimating device and a transflector for use in a system having a backlight is disclosed herein. In one embodiment of the application, the collimating device and the transflector each include an immersing layer, a reflecting layer, and an optical element layer formed from a plurality of three-dimensional, optical elements. Each optical element is tapered such that a small area end has a horizontal plane cross-sectional area that is less than that of a wide area end. The optical elements of the collimating device are tapered towards the backlight and the optical elements of the transflector are tapered away from the backlight. The reflecting layer has apertures which correspond to the position and shape of the light input ends of the optical elements.

Claims

1. An optical layer comprising a light output side and a light input side having a light input side plane, the optical layer comprising:

a plurality of three-dimensional light collimating elements, wherein each light collimating element comprises;

a light input end having a predetermined input aperture;

a light output end; and

,

a polygonal horizontal plane cross-section;

wherein each light collimating element is tapered to comprise at least one linear section and at least one curved section in a vertical plane cross-section of the light collimating element that is an approximation of a compound parabolic concentrator, wherein the curved section is defined by an arc of a circle, and a slope of the curved section matches a slope of the at least one linear section at an intersection point of the at least one curved section and the at least one linear section, such that uncollimated light entering the predetermined input aperture from multiple angles emerges from the light output end as a substantially collimated uniform sheet of light; and

a reflective surface, wherein the reflective surface is on the light input side plane of the optical layer, and is adjacent to the predetermined input aperture of the light input end of each light collimating element, and provides recycling of light for input to the optical layer when the reflective surface of the optical layer faces and is opposite a reflective surface of a light source.

2. The optical layer of claim 1, wherein the light output end of each light collimating element has a predetermined output aperture.

3. The optical layer of claim 2, wherein dimensions of at least one of the predetermined input aperture of the light input end or the predetermined output aperture of the light output end of each light collimating element are selected to maximize the substantially collimated uniform sheet of light exiting the light output end for a desired viewing angle.

4. The optical layer of claim 1, wherein the optical layer simultaneously collimates light, recycles light and maximizes light distribution at a desired viewing angle.

5. The optical layer of claim 1, wherein the optical layer is a single layer.

6. The optical layer of claim 1, wherein the approximation of the compound parabolic concentrator is a circular approximation.

7. The optical layer of claim 6, wherein the circular approximation of the compound parabolic concentrator preserves optical properties of the compound parabolic concentrator.

8. The optical layer of claim 1, wherein the tapered plurality of light collimating elements are surrounded by air.

9. The optical layer of claim 1, wherein the plurality of light collimating elements are formed from a polymer having a first index of refraction and the plurality of light collimating elements are surrounded by a second polymer having a second index of refraction, the first index of refraction being higher than the second index of refraction to obtain substantial total internal reflection.

10. The optical layer of claim 1, wherein the plurality of light collimating elements have a rectangular, square, or diamond-shaped horizontal plane cross-section.

11. The optical layer of claim 1, wherein the plurality of light collimating elements have a lenticular horizontal plane cross-section.

12. The optical layer of claim 1, wherein the plurality of light collimating elements are in contact with each other at the light output side of the optical layer.

13. The optical layer of claim 1, wherein the plurality of light collimating elements contact each other in a common polymer sheet.

14. An optical film, comprising:

at least one light collimating element, wherein the at least one light collimating element is tapered and comprises a light output end and a light input end having a predetermined input aperture, the taper comprising at least one linear section and at least one curved section in a vertical plane cross-section of the at least one light collimating element that is an approximation of a compound parabolic concentrator, wherein the curved section is defined by an arc of a circle, and a slope of the curved section matches a slope of the at least one liner section at an intersection point of the at least one curved section and the at least one linear section, such that uncollimated light entering the predetermined input aperture from multiple angles emerges from the light output end as a substantially collimated uniform sheet of light; and

a reflective layer, wherein the reflective layer is coincident with a horizontal plane containing a light input end of the at least one optical element facing a backlight and a backlight reflector and comprises at least one aperture corresponding to the predetermined input aperture of the at least one light collimating element and provides recycling of light for input to the at least one light collimating element when the reflective layer of the optical film is opposite the backlight reflector.

15. The optical film of claim 14, wherein the light output end of the at least one collimating element has a predetermined output aperture.

16. The optical film of claim 15, wherein dimensions of at least one of the predetermined input aperture of the light input end or the predetermined output aperture of the light output end of the at least one light collimating element are selected to maximize the substantially collimated uniform sheet of light exiting the light output end for a desired horizontal viewing angle or vertical viewing angle.

17. The optical film of claim 14, wherein the optical film simultaneously collimates light, recycles lights, and maximizes light distribution at a desired horizontal viewing angle or vertical viewing angle.

18. The optical film of claim 14, wherein the optical film is a single-layer film.

19. The optical film of claim 14, wherein the approximation of the compound parabolic concentrator is a circular approximation.

20. The optical film of claim 19, wherein the circular approximation of the compound parabolic concentrator preserves optical properties of the compound parabolic concentrator.

21. The optical film of claim 14, wherein the at least one light collimating element is surrounded by air.

22. The optical film of claim 14, wherein the at least one light collimating element is formed from a polymer having a first index of refraction and the at least one light collimating element is surrounded by a second polymer having a second index of refraction, the first index of refraction being higher than the second index of refraction to obtain substantial total internal reflection.

23. The optical film of claim 14, wherein the at least one light collimating element has a rectangular, square, or diamond-shaped horizontal plane cross-section.

24. The optical layer of claim 14, wherein the at least one light collimating element has a lenticular horizontal plane cross-section.

25. The optical film of claim 14, wherein the at least one light collimating element is in contact with another light collimating element at a light output side of the optical film.

26. The optical film of claim 14, wherein the at least one light collimating element is in contact with another light collimating element in a common polymer sheet.

27. A collimating device for use in a system having a backlight and a backlight reflector, the collimating device comprising:

an optical element layer formed from a plurality of two-dimensional or three-dimensional optical elements, each optical element comprising a light output end and a light input end having a predetermined input aperture, and being tapered to comprise at least one linear section and at least one curved section in a vertical plane cross-section of the optical element that is an approximation of a compound parabolic concentrator, wherein the curved section is defined by an arc of a circle, and a slope of the curved section matches a slope of the at least one linear section at an intersection point of the at least one curved section and the at least one linear section, such that uncollimated light entering the predetermined input aperture from multiple angles emerges from the light output end as a substantially collimated uniform sheet of light; and

a reflecting layer, wherein the reflecting layer comprises apertures corresponding to the predetermined input aperture of the light input end of each optical element and directs light to The backlight reflector to be redirected to The predetermined input aperture of the light input end of each optical element when the reflecting layer is opposite the backlight and backlight reflector.

28. The collimating device of claim 27, wherein the reflecting layer further is flat or textured.

29. The collimating device of claim 27, wherein the reflecting layer provides controlled diffuse or specular scattering of light.

30. The collimating device of claim 27, wherein the light output end of The optical element has a predetermined light output aperture.

31. The collimating device of claim 30, wherein dimensions of at least one of the predetermined input aperture of the light input end or the predetermined output aperture of each optical element are selected to maximize the substantially collimated uniform sheet of light exiting the light output end for a desired horizontal viewing angle or vertical viewing angle.

32. The collimating device of claim 27, wherein the optical element layer simultaneously collimates light, recycles light and maximizes light distribution at a desired horizontal viewing angle or vertical viewing angle.

33. The collimating device of claim 27, wherein the device is a single layer.

34. The collimating device of claim 27, wherein the approximation of the compound parabolic concentrator is a circular approximation.

35. The collimating device of claim 34, wherein the circular approximation of the compound parabolic concentrator preserves optical properties of the compound parabolic concentrator.

36. The collimating device of claim 27, wherein the plurality of optical elements have a lenticular shape and a rectangular horizontal plane cross-section.

37. The collimating device of claim 27, wherein the plurality of optical elements have a horizontal plane lenticular cross-section.

38. The collimating device of claim 27, wherein the plurality of optical elements are in contact with each other at the light output side of the optical element layer.

39. The collimating device of claim 27, wherein the plurality of optical elements contact each other in a common polymer sheet.

40. The collimating device of claim 27, wherein the optical element is formed from a polymer having a first index of refraction and the optical element is surrounded by a second polymer having a second index of refraction, the first index of refraction being higher than the second index of refraction to obtain substantial total internal reflection.

41. A method of manufacturing a collimating device, comprising the steps of:

providing a reflective layer;

providing an optical element layer;

forming an array of microstructures in the optical element layer, wherein each microstructure has a light input end, a light output end, and a polygonal horizontal plane cross-section, and each microstructure is tapered to comprise at least one linear section and at least one curved section in a vertical plane cross-section of the microstructure that is an approximation of a compound parabolic concentrator, wherein the curved section is defined by an arc of a circle, and a slope of the curved section matches a slope of the at least one linear section at an intersection point of the at least one curved section and the at least one linear section, such that uncollimated light entering the light input end from multiple angles emerges from the light output end as a substantially collimated uniform sheet of light;

abutting the array of microstructures of the optical element layer against the reflective layer;

applying heat or pressure to the optical element layer to puncture the reflective layer; and

penetrating the array of microstructures a predetermined distance through the reflective layer,

wherein the step of forming an array of microstructures thither comprises the step of selecting an input aperture dimension of the light input end and an output aperture dimension of the light output end of each micro structure to maximize the substantially collimated uniform sheet of light exiting the light output end of the microstructures for a desired viewing angle.

42. The method of claim 41, further comprising the step of recycling light within the device when the reflective layer of the device is opposite a reflective surface of a light source.

43. The method of claim 41, further comprising simultaneously collimating light, recycling light and maximizing light distribution at a desired viewing.

44. The method of claim 41, further comprising utilizing a circular approximation to approximate the compound parabolic concentrator.

45. The method of claim 41, further comprising preserving optical properties of the compound parabolic concentrator by using a circular approximation of the compound parabolic concentrator.