Optical devices for guiding illumination

• US 8,369,678 B2
• Filed: 07/27/2009
• Issued: 02/05/2013
• Est. Priority Date: 02/10/2006
• Status: Active Grant

• Current Assignee: Viavi Solutions, Inc. (Lumentum Holdings Inc.)
• Original Assignee: RPC Photonics, Inc. (Lumentum Holdings Inc.)
• Inventors: Chakmakjian, Stephen H., Schertler, Donald J., Sales, Tasso, Morris, G. Michael
• Primary Examiner(s): Peng, Charlie
• Assistant Examiner(s): LAM, HUNG Q
• Application Number:
  US12/460,951
• Publication Number:
  US 20090297113A1
• Time in Patent Office: 1,289 Days
• Field of Search: 385 2- 8, 385 10- 29, 385 32- 37, 385 53- 56, 385 58- 65, 385/31, 385/39, 385/43, 385/129, 385/131, 385/146, 385/147, 385/901, 349/15, 349/56, 349/61, 349/62, 349/65, 349/66, 349/70, 349/95, 349/117, 349/121, 349/159, 359/559, 359/833, 359/834, 359/869, 362/19, 362/26, 362/31, 362/32, 362/260, 362/268, 362/328, 362330-333, 362/339, 362/346, 362/347
• US Class Current: 385/146
• CPC Class Codes: G02B 6/0028 Light guide, e.g. taper
• 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 6/0048 with stepwise taper
• CPC Class Codes: G02B 6/0061 to provide homogeneous light output intensity

Abstract

Optical devices for guiding illumination are provided each having a body of optical material with staircase or acutely angled ramp structures on its top surface for distributing light inputted from one end of the device from the front exit faces of such structures along certain angular orientations, while at least a substantial portion of the light is totally internally reflected within the body until distributed from such front exit faces. Optical devices are also provided each have a body of optical material having a bottom surface with acutely angled ramp structures and falling structures which alternate with each other, such that light is totally internally reflected within the device until reflected by such ramp structures along the bottom surface to exit the top surface of the device or transmitted through the ramp structures to an adjacent falling structure back into the device. Acutely angled ramp structures may be provided on both top and bottom surfaces of optical devices for distributing light along such top surface. Illumination apparatuses are also provided using such optical devices.

Claims

1. An optical device for guiding illumination comprising:

a body having a first surface and a second surface, each of said first and second surfaces being on opposite sides of the body, in which said first surface has a plurality of ramp structures, said body has an optical axis extending along a dimension parallel to said second surface; and

each of said ramp structures having a ramp surface at a first acute angle with respect to said optical axis, a front exit face following said ramp surface at a second acute angle with respect to the normal of said optical axis, in which light when inputted at one end of said body is substantially totally internally reflected within said body until exiting said body through the front exit face of two or more of said ramp structures, wherein NA is the numerical aperture of the light inputted said one end of said device, and said NA and said second acute angle are in inverse relationship with each other.

2. The device according to claim 1 wherein the end of said front exit face contacts the start of the next ramp structure along said surface.

3. The device according to claim 1 wherein said first and second surfaces represent the top and bottom surfaces, respectively, of the device, and said second surface is substantially flat.

5. The device according to claim 1 wherein said body has a first end representing said one end for inputting light and a second end, and said ramp structures each successively tapers toward said second surface between said first and second ends gradually reducing the thickness of the device.

6. The device according to claim 5 wherein the thickness at said second end is substantially zero, and substantially all of said light inputted into said body exits through the said front exit face of said two or more ramp structures.

7. The device according to claim 1 wherein the front exit faces of two of more of said ramp structures vary from each other.

8. The device according to claim 1 wherein said light exiting through the front exit face of said two or more ramp structures distributes said light over a certain angular range from said body.

9. The device according to claim 1 wherein said light exiting through the front exit face of said two or more ramp structures distributes said light over a wide angle from said body.

10. The device according to claim 1 wherein said front exit face of each of said ramp structures is curved.

11. The device according to claim 1 wherein said front exit face of each of said ramp structures is flat.

12. The device according to claim 1 wherein said body has a first end representing said one end for inputting light, and a second end, and said ramp structures extend along a dimension between said first end and second end, and said body is curved along said dimension between said first and second ends.

13. The device according to claim 1 wherein said body has a first end representing said one end for inputting light, and a second end, and said ramp structures extend along a dimension between said first end and second end representing the length of the device, and said body is curved along the width of said device.

14. The device according to claim 1 wherein said body has an input portion between a first one of said ramp structures and said one end for inputting light.

15. The device according to claim 14 wherein said input portion is shaped to facilitate transmission of light from said one end to the part of said body having said ramp structures.

16. The device according to claim 14 wherein said body has a first end representing said one end for inputting light, and a second end, and said ramp structures extend between said first end and second end, and said input portion is tapered in the direction of a first one of said ramp structure to said first end along at least one of said axis or a dimension perpendicular to said axis.

17. The device according to claim 1 wherein said body represents a cylinder.

18. The device. according to claim 1 wherein said ramp structures represent first ramp structures, said body has a first portion and a second portion, in which said first ramp structures are provided along said first surface of said first portion, said device further comprising second ramp structures and falling structures along said second surface which alternate with each other, and light when received from said first portion of said body is totally or substantially internally reflected within said second portion of said body unless transmitted through one of said second ramp structures out of and back into said body via an adjacent one of said falling structures until directed by reflection from the ramp surface of one of said second ramp structures to exit through said first surface.

19. The device according to claim 18 wherein each of said second ramp structures comprises a rising surface that is at an acute angle with respect to said axis, and each of said falling structures comprises a falling surface which is at an acute angle with respect to the normal of said axis, and between each one of the falling structures and the next one of said second ramp structures is at least a flat surface substantially parallel to said first surface of said second portion.

20. The device according to claim 19 wherein said falling surface of each of said falling structures represents a prismatic surface.

21. The device according to claim 19 wherein the second surface is substantially parallel to said first surface along said second portion from said first portion to a first of said second ramp structures, and the flat surface subsequent a first of said falling structures from said first portion along said second surface is at a level further from said first surface than the second surface extending from said first portion to the first of said second ramp structures, and the flat surface subsequent each of said falling structures after a second of said falling structures from said first portion along said second surface is at a level closer to said first surface along said second portion than the previous flat surface, thereby reducing the thickness of the optical device along said second portion.

22. The device according to claim 21 wherein each of said second ramp structures and said falling structures increase in size proportionally with the reducing of thickness along said second portion.

23. The device according to claim 19 wherein the rising surface of each of the second ramp structures is segmented into multiple surfaces of progressive steeper acute angles with respect to said axis.

24. The device according to claim 19 wherein the rising surface of each of the ramp structures has a continuously varying slope.

25. The device according to claim 19 wherein the bottom surface along at least said second ramp structures and falling structures has reflective material.

26. The device according to claim 1 wherein the light exiting through said first surface is in accordance with one of more of the height of the ramp surface of said two or more ramp structures, the first acute angle of the ramp surface of said two or more ramp structures, the second acute angle of the front exit face of said two or more ramp structures, and the spacing between adjacent ones of said two or more ramp structures.

27. The device according to claim 1 wherein the height of the ramp surface, the first acute angle of the ramp surface, the second acute angle of the front exit face arc the same for said two or more ramp structures along said first surface, and the spacing between any adjacent ones of said two or more ramp structures are the same along said surface.

28. The device according to claim 1 further comprising a source for light inputted into said one end of said device.

29. The device according to claim 28 wherein said source represents a lamp, a single LED, an LED array, or a fiber optic light source.

30. The device according to claim 1 further comprising a housing having at least said body.

31. The device according to claim 30 wherein said housing is mountable on a surface.

32. The device according to claim 30 further comprising a source for light inputted into said one end of said device wherein said source comprises a fiber optic with an input end external said housing for receiving illumination and an output end extending into said housing for delivering light to said device.

40. The device according to claim 1 wherein said body has a first end representing said one end for inputting light and a second end, and at least part of said device tapers in thickness between said first and second ends.

41. The device according to claim 1 wherein said body has a first end representing said one end for inputting light, and a second end, and said ramp structures extend along a dimension between said first end and second end, and said body is one of curved or non-curved along said dimension between said first and second ends.

42. The device according to claim 1 wherein said body comprises multiple portions in which one of said portions has said ramp structures along said first surface, and another of said portions has another plurality of acutely angled ramp structures along said second surface providing illumination. along said first surface of said another of said portions.

43. The device according to claim 1 wherein two or more of said ramp structures vary from each other in accordance with height of the ramp structures.

44. The device according to claim 1 wherein for each of said two or more ramp structures in a direction along said first surface away from said one end of said body the ramp surface is forwardly tilted at said first acute angle with respect to said axis until a forwardmost end from which the front exit face extends backwardly tilted at said second acute angle with respect to the normal of the axis.

46. The device according to claim 1 wherein said body is curved about an axis perpendicular to said optical axis of said device.

47. The device according to claim 1 wherein said body is curved about an axis parallel to said optical axis of said device.

48. The device according to claim 1 wherein said body forms a cylinder about an axis parallel to said optical axis of said device.

49. The device according to claim 1 wherein said optical axis is generally aligned with a plane parallel with said second surface.

58. The device according to claim 1 wherein said front exit face is backwardly tilted at said second acute angle with respect to the normal of the axis.

4. An optical for guiding illumination comprising:

a body having a first surface and a second surface, each of said first and second surfaces being on opposite sides of the body, in which said first surface has a plurality of ramp structures, said body has an optical axis extending along a dimension parallel to said second surface; and

each of said ramp structures having a ramp surface at a first acute angle with respect to said optical axis, and a front exit face at a second acute angle with respect to the normal of said optical axis, in which light when inputted at one end of said device is substantially totally internally reflected within said body until substantially distributed by exiting through the front exit face of each of said ramp structures, and wherein NA is the numerical aperture of the light inputted said one end of said device, and said NA and said second acute angle are in inverse relationship with each other, and wherein each adjacent pair of said ramp structures is separated by a flat surface substantially parallel to said second surface; and

said body has a first end representing said one end for inputting light and a second end, and a plurality of said ramp structures each successively tapers toward said second surface between said first and second ends reducing the thickness of the body between said first surface and said second surface while maintaining said flat surface between each adjacent pair of ramp structures substantially parallel to said second surface, wherein said second surface is substantially flat between said first and second ends.

59. The device according to claim 4 wherein for each of said ramp structures the ramp surface and the front exit face meet at an acute angled apex.

33. A device for guiding illumination having an optical axis comprising:

a body having a top surface with a series of structures extending in the same direction as said axis of said body, and a bottom surface which extends along a direction parallel to said axis; and

each of said structures comprises a rising surface followed by falling surface, wherein for each of said structures in a direction along said top surface away from said one end of said body the rising surface forwardly tilts at an angle with respect to said axis to meet at an apex the falling surface which backwardly tilts at an angle with respect to the normal of said axis to enable light when inputted from one end of said body to be substantially emitted from said body through said falling surface of said structures while being totally or substantially internally reflected along the rising surface of said structures and said bottom surface, and wherein NA is the numerical aperture of the light inputted said one end of said device, and said NA and said angle of said falling surface arc in inverse relationship'"'"'with each other.

34. An apparatus comprising:

a light guiding device having an optical axis extending the length of the device and at least structures each having a ramp at a first angle with respect to said optical axis with a tilted front face at a second angle with respect to the normal of said optical axis, and light when received at one end of the device substantially exits through the front face of said structures, wherein NA is the numerical aperture of the light received at said one end of the device, and said NA and said second angle are in inverse relationship with each other.

35. The apparatus according to claim 34 further comprising a housing having at least said light guiding device.

36. The apparatus according to claim 35 wherein said housing further has a light source for inputting light into said light guiding device.

37. The apparatus according to claim 35 wherein said housing is mountable on a surface.

38. The apparatus according to claim 34 further comprising a light source for inputting light into said light guiding device.

39. The apparatus according to claim 38 wherein said light source represents a lamp, a single LED, an LED array, or a fiber optic light source.

56. The apparatus according to claim 34 wherein light exiting through the front face of said structures provides backlight LCD illumination.

45. An optical device for guiding illumination comprising:

a body having a first surface and a second surface, each of said first and second surfaces being on opposite sides of the body, in which said first surface has a plurality of ramp structures, said body has an optical axis extending along a dimension parallel to said second surface, in which light when inputted at one end of said body is substantially totally internally reflected within said body until exiting said body through the front exit face of two or more of said ramp structures, wherein;

Θ

_R represents the angle of the ramp surface with respect to said axis;

Θ

_EF represents the angle of said front exit face of each of said stnictures with respect to the normal of said axis;

said body is of material having a refractive index;

NA is the numerical aperture of the light inputted said one end of said device;

R_n is a ratio of the refractive index of the material of said body to a refractive index of the medium surrounding said body; and

said angles Θ

_R and Θ

_EF are selected in accordance with at least equations;

60. The device according to claim 45 wherein each of said ramp structures has a ramp surface at a first acute angle with respect to said optical axis, and a front exit face at a second acute angle with respect to the normal of said optical axis.

50. An optical element for guiding illumination comprising:

two ends;

a first surface and a second surface opposite said first surface, in which said first and second surfaces extend between said two ends; and

said first surface has a plurality of structures each comprising a third surface followed by a fourth surface, in which said third surface meets said fourth surface at an apex, said third surface slopes upward in a first direction away from said second surface at a first angle with respect to a dimension substantially parallel to that portion of said second surface opposite that portion of said first surface having the third surface, and said fourth surface slopes backward in a second direction toward said second surface at a second angle with respect to a dimension substantially perpendicular to that portion of said second surface opposite that portion of said first surface having said fourth surface, wherein all or at least a substantial portion of light when received from one of sa;

d ends is totally internally reflected within said device until exiting from said device through the fourth surface of the structures, wherein NA is the numerical aperture of the light inputted said one of said ends, and said NA and said second angle at which said second surface slopes backward in said second direction are in inverse relationship with each other.

51. The optical element according to claim 50 wherein the fourth surface of each of two or more of said structures is adjacent the third surface of the next one of said two or more of said structures along said first surface.

52. The optical element according to claim 51 wherein the third surface, second surface, first angle, and second angle are the same for two or more of said structures.

53. The optical element according to claim 51 wherein two or more said structures each further comprise a first edge where the third surface ends and the fourth surface begins, and a second edge where the fourth surface ends of one of said two or more structure ends and the third surface begins of next one of said two or more structures when present, in which along said first surface the first edge of each of said two or more structures is closer in distance to the opposing said second surface than the first edge of the previous one of two or more structures when present, and the second edge of each of said two or more structures is closer in distance to the opposing said second surface than the second edge of the previous one of two or more structures when present.

54. The optical element according to claim 50 wherein at least one of said structures comprises a fifth surface following the fourth surface of the structure, said fifth surface being substantially parallel to that portion of said second surface opposite that portion of said first surface having the fifth surface, and the fifth surface is adjacent the third surface of the next one of said structures along said first surface.

55. The optical element according to claim 50 wherein two or more said structures each further comprise:

an edge where the third surface ends and the fourth surface begins of the structure, in which the edge of each of said two or more structures is at a closer in distance to the opposing said second surface than the edge of the previous one of said two or more structures when present; and

a fifth surface following the fourth surface of the structure, said fifth surface being substantially parallel to that portion of said second surface opposite that portion of said first surface having the fifth surface, the fifth surface is adjacent the third surface of the next one of said two or more structures along said first surface, and along said first surface the fifth surface of each of said two or more said structures is closer in distance to the opposing said second surface than the fifth surface of the previous one of said two or more structures when present.

61. The optical element according to claim 50 wherein said second surface opposite said plurality of structures along said first surface is substantially flat.

57. An optical device for guiding illumination comprising:

a body having a first surface and a second surface, each of said first and second surfaces being on opposite sides of the body, in which said first surface has a plurality of ramp structures, said body has an optical axis extending along a dimension parallel to said second surface; and

each of said ramp structures having a ramp surface at a first acute angle with respect to said optical axis, and a front exit face at a second acute angle with respect to the normal of said optical axis, in which light when inputted at one end of said body is substantially totally internally reflected within said body until exiting said body through the front exit face of two or more of said ramp structures which, wherein for each of said ramp structures in a direction along said first surface away from said one end of said body the ramp surface is forwardly-tilted at said first acute angle with respect to said axis until a forwardmost end forms an apex with the front exit face from which the front exit face extends backwardly tilted at said second acute angle with respect to the normal of the axis, wherein NA is the numerical aperture of the light inputted said one end of said device, and said NA and said second acute angle are in inverse relationship with each other.