Optical devices for guiding illumination

• US 20070189701A1
• Filed: 02/10/2006
• Published: 08/16/2007
• 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: Sales, Tasso, Schertler, Donald, Chakmakjian, Stephen, Morris, G.
• Granted Patent: US 7,593,615 B2
• Time in Patent Office: Days
• 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 with a surface having one of a staircase structure or a plurality of acutely angled ramp structures to provide a plurality of front exit faces, in which light when inputted at one end of said device is distributed by said front exit faces and at least a substantial portion of said light is internally reflected within said body until distributed from the front exit face of each of said ramp structures.

20. The device according to claim 1 wherein said surface represents a top surface, said ramp structure represent first ramp structures, said body has a first portion and a second portion, in which said first ramp structures are provided along said top surface of said first portion, said device further comprising

second ramp structures and falling structures along said bottom surface which alternate with each other, and light when received from said first portion of said body is totally internally reflected within said second portion of said body until distributed by reflection from the ramp surface of each of said second ramp structure to exit said top surface or transmitted from said ramp surface back into next adjacent falling structure.

21. The device according to claim 20 wherein each of said second ramp structures comprise a rising surface that is at an acute angle with respect to said axis, and each of said falling structures comprises a falling surface with is at an acute angle with respect to the normal of said axis, and then a surface substantially parallel to said top surface.

22. The device according to claim 21 wherein said falling surface of each of said falling structure represent a prismatic surface.

23. The device according to claim 21 wherein the first flat surface is lower than the back surface extending from said one end to the first of said second ramp structure, and the flat surface of each of the falling structures after the first flat surface is a higher level than the previous flat surface along the length of the optical device, thereby reducing the thickness of the optical device.

24. The device according to claim 23 wherein each of said second ramp structures and said falling structures increase in size proportionally with the reducing of thickness along said bottom surface.

25. The device according to claim 21 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.

26. The device according to claim 21 wherein the rising surface of each of the ramp structures has a continuously varying slope.

27. The device according to claim 21 wherein the bottom surface along at least said second ramp structures and falling structure has reflective material.

2. An optical device for guiding illumination comprising:

a body with a surface having a plurality of acutely angled ramp structures; and

each of said ramp structures having a front exit face for distributing said light, in which light when inputted at one end of said device is substantially totally internally reflected within said body until distributed the front exit face of each of said ramp structures.

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

4. The device according to claim 2 wherein said surface represents a first surface, said body has a second surface, 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 4 wherein each adjacent pair of said ramp structures is separated by a flat surface substantially parallel to and facing said second surface.

6. The device according to claim 4 wherein said body has first end representing said one end for inputting light and a second end, each of said ramp structures are equal in size along said first surface, and said ramp structures each successive taper toward said second surface between said first and second ends gradually reducing the thickness of the device.

7. The device according to claim 6 wherein the thickness at said second end is substantially zero, and substantially all of said light inputted into said body is distributed from the said front exit face of said ramp structures.

8. The device according to claim 2 wherein body has 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 axis of the device, in which said ramp structures each have a ramp surface at an acute angle with respect to said axis, and the front exit face of each of said ramp structures represents a surface at an acute angle with respect to the normal of said axis.

9. The device according to claim 8 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 structures with respect to the normal of said axis;

said body is of material having a refractive index (NA);

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;

${\mathrm{\Theta <br><br>}}_{\mathrm{EF}}\le <br><br>\arcsin <br><br>\left[\frac{1}{R_n}\right]-\arcsin <br><br>\left[\frac{1}{R_n}<br><br>\mathrm{NA}\right]$$\arcsin <br><br>\left[R_n*\sin <br><br>\left({\mathrm{\Theta <br><br>}}_{\mathrm{EF}}\right)\right]-{\mathrm{\Theta <br><br>}}_{\mathrm{EF}}\ge <br><br>{\mathrm{\Theta <br><br>}}_R.$

10. The device according to claim 2 wherein said light distributed from the front exit face of each of said ramp structures distributes said light over a certain angular range from said body.

11. The device according to claim 2 wherein said light distributed from the falling surface of each of said structures distributes said light over a wide angle from said body.

12. The device according to claim 2 wherein said front exit face of each of said ramp structures is curved.

13. The device according to claim 2 wherein said front exit face of each of said ramp structures is flat.

14. The device according to claim 2 wherein 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.

15. The device according to claim 2 wherein 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.

16. The device according to claim 2 wherein said body has a input portion between said first one of said ramp structures said one end for inputting light.

17. The device according to claim 16 wherein said input portion is shaped to facilitate transmission of light from said one end to said body having said ramp structures.

18. The device according to claim 16 wherein body has 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 axis of the device, 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.

19. The device according to claim 2 wherein said body represents a cylinder.

28. The device according to claim 8 wherein the light distribution from said top surface of the device is in accordance with one of more of the height of the ramp surface of each of said ramp structures, the angle of the ramp surface of each of said ramp structures, the angle of the front exit face of each of said ramp structures, and the spacing between adjacent ones of said ramp structures.

29. The device according to claim 8 wherein the height of the ramp surface, the angle of the ramp surface, and the angle of the front exit face are the same for each of said ramp structures along said top surface, and wherein the spacing between adjacent ones of said ramp structures are the same along said surface.

30. The device according to claim 8 wherein the height of the ramp surface, the angle of the ramp surfaces, and the angle of the front exit face vary for one or more of said ramp structures along said surface

31. The device according to claim 30 wherein the spacing between adjacent ones of said ramp structures vary for one or more of said ramp structures along said surface.

32. The device according to claim 2 further comprising a source for light inputted into said one end of said device.

33. The device according to claim 32 wherein said source represents a lamp, a single LED, an LED array, or a fiber optic light source.

34. The device according to claim 32 wherein said source and said device are located in a housing.

35. The device according to claim 34 wherein said housing is mountable on a surface.

36. The device according to claim 32 wherein said device is located in a housing, and 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.

37. A device for guiding illumination comprising:

a body having a top surface with a series of structures, and a bottom surface, in which said series of structures extend from one end of the device along a dimension representing the axis of the device; and

each of said structures comprises a rising surface followed by falling surface, in which said rising surface and said falling surface are angled with respect to said axis to enable distribution of light when inputted said body at said one end from each said falling surface of said structures while being totally or substantially internally reflected along the rising surface of said structures and said bottom surface.

38. A device for guiding illumination comprising:

a body having a bottom surface with a plurality of ramp structures and falling structures, and a top surface, in which said ramp structures and falling structures alternate with each other along said bottom surface, and said ramp structures and falling structures extend along a dimension representing the axis of the device which is substantially parallel to said top surface, wherein light when received from one end of said body is totally internally reflected within said body until distributed by reflection from one of said ramp structures to exit from said top surface or transmitted through one of said ramp structures back into said body via an adjacent one of said falling structures.

39. The device according to claim 38 wherein each of said ramp structures comprise 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 then a surface substantially parallel to said top surface.

40. The device according to claim 39 wherein said falling surface of each of said falling structure represent a prismatic surface.

41. The device according to claim 39 wherein the first flat surface is lower than the back surface extending from said one end to the first of said ramp structure, and the flat surface of each of the falling structures after the first flat surface is a higher level than the previous flat surface along the length of the optical device, thereby reducing the thickness of the optical device.

42. The device according to claim 38 wherein each of said ramp structures and said falling structures increase in size proportionally with the reducing of thickness along said bottom surface.

43. The device according to claim 39 wherein the rising surface of each of the ramp structures is segmented into multiple surfaces of progressive steeper acute angles with respect to said axis.

44. The device according to claim 39 wherein the rising surface of each of the ramp structures has a continuously varying slope.

45. The device according to claim 38 wherein said bottom surface has reflective material.

46. The device according to claim 38 further comprising a source for inputting light inputted into said one end of said device.

47. The device according to claim 46 wherein said source represents a lamp, a single LED, an LED array, or a fiber optic light source.

48. The device according to claim 46 wherein said source and said device are located in a housing.

49. The device according to claim 48 wherein said housing is mountable on a surface.

50. The device according to claim 38 wherein said device is located in a housing, and 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.

51. An optical device for guiding illumination comprising:

a body having top surface and a bottom surface, and a plurality of successive portions from an input end for inputting light along the length of the device;

the top surface of at least one of said portions has a plurality of first ramp structures having front exit faces in which light is capable of being reflected within said one of said portions for distribution from said front exit faces along said top surface; and

the bottom surface of at least one other of said portions has a plurality of second ramp structures in which light is capable of being reflected within said one other of said portions for distribution by reflection from one of said second ramp structures to exit from said top surface.

52. The optical device according to claim 51 wherein light exiting said optical device from said first ramp structures and said second ramp structure combined to provide certain light distribution.

53. An illumination apparatus comprising:

a light guiding device having a top surface and a bottom surface, and at least one of said top and bottom surfaces comprising a pattern of acutely angled ramp structures providing illumination along said top surface, in which said ramp structures when present along said bottom surface direct light out of said top surface and said ramp structure when present along said top surface direct light from acutely angled exit faces of said ramp structures; and

a light source for inputting light into said light guiding device.

54. The apparatus according to claim 53 further comprising a housing having at least said light guiding device.

55. The apparatus according to claim 54 wherein said housing further has said light source.

56. The apparatus according to claim 54 wherein said housing is mountable on a surface.

57. The apparatus according to claim 53 wherein said light source represents a lamp, a single LED, an LED array, or a fiber optic light source