Light-Tracking Optical Device and Application to Light Concentration

• US 20120056081A1
• Filed: 08/23/2011
• Published: 03/08/2012
• Est. Priority Date: 09/07/2010
• Status: Active Grant

• Current Assignee: Glint Photonics, Inc.
• Original Assignee: Glint Photonics, Inc.
• Inventors: Kozodoy, Peter
• Granted Patent: US 8,634,686 B2
• Time in Patent Office: Days
• US Class Current: 250/227.25
• CPC Class Codes: F24S 23/00 Arrangements for concentrating solar-rays for solar heat collectors
• CPC Class Codes: F24S 23/12 Light guides
• CPC Class Codes: F24S 50/20 for tracking
• CPC Class Codes: G02B 6/0023 provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
• CPC Class Codes: G02B 6/26 Optical coupling means G02B6/36, G02B6/42 take precedence
• CPC Class Codes: G02B 6/3538 based on displacement or deformation of a liquid controlling the intensity of light by displacement or deformation of a fluid in general G02B26/004; fluid-filled lens of variable focal length G02B3/14
• CPC Class Codes: H01L 31/0543 comprising light concentrating means of the refractive type, e.g. lenses
• CPC Class Codes: H01L 31/0547 comprising light concentrating means of the reflecting type, e.g. parabolic mirrors, concentrators using total internal reflection
• CPC Class Codes: Y02E 10/44 Heat exchange systems
• CPC Class Codes: Y02E 10/47 Mountings or tracking
• CPC Class Codes: Y02E 10/52 PV systems with concentrators

Abstract

An automatic optical coupling device that uses liquid to couple focused light into a light-guide is described. The liquid moves within a chamber or layer via the thermocapillary effect in order to automatically track and couple a moving spot of focused light. Also provided is the application of these coupling devices in an array feeding into a common light-guide, optical designs to improve the performance of these arrays, and the application of such arrays to light collection.

Claims

1. An apparatus configured to couple light into a light-guiding structure, the apparatus comprising:

a fluid tracking layer between a reorienting element and a light-guiding layer, the light-guiding layer being capable of transporting light in a first direction through a bulk portion of the light-guiding layer, wherein said fluid tracking layer is comprised of a cladding fluid layer and a coupling fluid layer;

wherein

in the absence of a narrow light beam incident the cladding fluid layer is comprised of a continuous layer substantially free of any voids or apertures; and

in the presence of a narrow light beam incident on the reorienting element and forming a coupling location, the cladding fluid layer is comprised of an aperture at or adjacent to the coupling location.

2. The apparatus of claim 1, wherein the aperture is at least partially filled with coupling fluid of the coupling fluid layer.

3. The apparatus of claim 1, wherein the cladding fluid layer is between at least a portion of the coupling fluid layer and the light-guiding layer.

4. The apparatus of claim 1, wherein the coupling fluid layer or the cladding fluid layer is contained within a chamber having a chamber sidewall.

5. The apparatus of claim 4, further comprising a plurality of chambers, wherein each chamber comprises a coupling fluid layer or a cladding fluid layer.

6. The apparatus of claim 1, wherein at least a portion of the coupling fluid layer is between the cladding fluid layer and the light-guiding layer.

7. The apparatus of claim 6, wherein the coupling fluid layer in combination with the light-guiding layer serve to guide light through the light-guiding structure, the guided light being transported through the bulk portion of the light-guiding layer and through a bulk portion of the coupling fluid layer.

8. The apparatus of claim 6, wherein the coupling fluid layer serves to guide light through the light-guiding structure, the guided light being transported through a bulk portion of the coupling fluid layer.

9. The apparatus of claim 1, further comprising an absorbing fluid layer between the reorienting element and the light-guiding layer.

10. The apparatus of claim 1, wherein the coupling fluid layer is comprised of a first fluid and the cladding fluid layer is comprised of a second fluid that is immiscible or partially miscible with the first fluid.

11. The apparatus of claim 1, wherein the coupling fluid layer is comprised of a first fluid that is selected from the group of materials consisting of aqueous solutions, water-soluble fluids, hydrocarbon oils, silicone oils, organic compounds, and fluorocarbon oils, and wherein the cladding fluid layer is comprised of a second fluid that is selected from the group of materials consisting of aqueous solutions, water-soluble fluids, hydrocarbon oils, silicone oils, organic compounds, and fluorocarbon oils.

12. The apparatus of claim 1, wherein the light-guiding layer has a first refractive index, the cladding fluid layer has a second refractive index which is less than the first refractive index, and the coupling fluid layer has a third refractive index which is greater than the second refractive index.

13. The apparatus of claim 1, wherein the reorienting layer is configured to deflect the incident light beam into the light-guiding layer at a substantial angle relative to a propagation direction of the incident light beam.

14. The apparatus of claim 1, wherein the light-guiding layer is comprised of a material selected from the group of materials consisting of glasses or polymers.

15. The apparatus of claim 1, wherein the reorienting element is comprised of a reorienting layer.

16. The apparatus of claim 15, wherein the reorienting layer reflects or refracts incident light.

17. The apparatus of claim 15, wherein different portions of the reorienting layer are configured to deflect incident light at different angles.

18. The apparatus of claim 15, wherein the reorienting layer is formed of a substantially non-porous material.

19. The apparatus of claim 15, wherein a surface of at least one of the reorienting layer or the light-guiding layer is coated with a coating that changes a wetting property of the surface.

20. The apparatus of claim 15, wherein the reorienting layer is a transmissive layer and is configured to be positioned between the light-guiding layer and the incident focused light.

21. The apparatus of claim 20, wherein the reorienting layer comprises a prism array.

22. The apparatus of claim 15, wherein the reorienting layer is a reflective layer comprising a sawtooth minor.

23. The apparatus of claim 22, the sawtooth mirror being configured to couple incident light that is tilted away from perpendicular incidence by an average angle α

into the light-guiding layer, wherein individual minors of the sawtooth mirror form angles of 30°

±

α

/2 relative to a plane of the reorienting layer.

24. The apparatus of claim 1, wherein the coupling region is located at or adjacent to a local temperature extremum within the light-guiding structure.

25. The apparatus of claim 1, wherein a portion of the incident focused light is absorbed at or adjacent to the coupling location.

26. The apparatus of claim 25, wherein the absorption of the incident focused light results in a local temperature maximum at or adjacent to the coupling location.

27. The apparatus of claim 1, wherein the light coupled into the light-guiding structure is sunlight or laser light.

28. An apparatus configured to couple light into a light-guiding structure, the apparatus comprising:

a light-guiding layer being capable of transporting light in a first direction through the light-guiding layer; and

a coupling region adjacent to or within the light-guiding layer and serving to couple incoming light into the light-guiding layer at a substantial angle relative to a propagation direction of the incoming light;

wherein

the coupling region is located at or adjacent to a local temperature extremum within the light-guiding structure, and the position of the coupling region can be adjusted by varying the location of the local temperature extremum.

29. The apparatus of claim 28, wherein the local temperature extremum is a local temperature maximum.

30. The apparatus of claim 29, wherein the local temperature maximum results from heating by absorption of the incoming light.

31. The apparatus of claim 30, wherein the incoming light is focused incoming light or laser light.

32. The apparatus of claim 31, wherein the coupling region is self-aligned with the focused incoming light or laser light.

33. The apparatus of claim 28, wherein a cross-sectional area of the coupling region is substantially smaller than a cross-sectional area of the light-guiding layer.

34. The apparatus of claim 28, wherein the light-guiding layer comprises a fluid containing one or more reorienting elements.

35. The apparatus of claim 34, further comprising a cladding wall layer contacting a side of the light-guiding layer.

36. The apparatus of claim 34, wherein the reorienting elements are droplets or bubbles.

37. The apparatus of claim 28, further comprising a device configured to accept the light transported through the light-guiding layer after it exits the light-guiding layer.

38. The apparatus of claim 37, wherein the device is a photovoltaic cell or a photodetector.

39. The apparatus of claim 37, the device being configured to accept light of a range of wavelengths, wherein the light-guiding layer is largely transparent to light having a wavelength within the range of wavelengths.

40. The apparatus of claim 28, further comprising a fluid tracking layer adjacent to the light-guiding layer.

41. The apparatus of claim 40, wherein the fluid tracking layer comprises one fluid or two or more immiscible or partially miscible fluids.

42. The apparatus of claim 40, wherein the coupling region is at least partially within the fluid tracking layer.

43. The apparatus of claim 40, wherein the fluid tracking layer comprises a cladding fluid layer having a lower refractive index than a refractive index of the light-guiding layer.

44. The apparatus of claim 28, further comprising a reorienting element serving to reorient light which is coupled into the light-guiding structure.

45. The apparatus of claim 28, further comprising a focusing element serving to focus light which is coupled into the light-guiding structure.

46. The apparatus of claim 45, wherein the focusing element comprises one or more lenses or one or more mirrors.

47. The apparatus of claim 45, the focusing element comprising a plurality of lenses or mirrors, wherein the lenses or minors are arrayed along a curved surface.

48. A device comprising at least two segments, each of the at least two segments comprising the apparatus of claim 28.

49. The device of claim 48, wherein the at least two segments are coupled to each other and are configured in varying orientations.

50. The apparatus of claim 28, wherein the light-guiding structure is planar.

51. The apparatus of claim 28, wherein the light-guiding structure is curved.

52. An apparatus configured to couple incident light into a light-guiding structure, the apparatus comprising:

a cladding fluid layer having a first refractive index adjacent to a light-guiding layer having a second refractive index, the light-guiding layer being capable of transporting light in a first direction through a bulk portion of the light-guiding layer; and

a coupling droplet having a third refractive index at least partially in the cladding fluid layer;

wherein

the coupling droplet is comprised of a first fluid and the cladding fluid layer is comprised of a second fluid different from the first fluid and immiscible or partially miscible with the first fluid.

53. The apparatus of claim 52, wherein the coupling droplet is free to move through the cladding fluid layer.

54. The apparatus of claim 52, wherein the second and third refractive indexes are each greater than the first refractive index.

55. The apparatus of claim 52, wherein the apparatus is configured such that the incident light is coupled into the light-guiding layer at a substantial angle relative to a propagation direction of the incident light.

56. The apparatus of claim 52, further comprising a reorienting element serving to reorient light which is coupled into the light-guiding structure.

57. The apparatus of claim 56, wherein the reorienting element is a reorienting layer.

58. The apparatus of claim 52, wherein the coupling droplet further serves to redirect the incident light.

59. The apparatus of claim 52, wherein the cladding fluid layer is contained within a chamber having a chamber sidewall.

60. The apparatus of claim 59, further comprising a plurality of chambers, wherein each chamber comprises a coupling droplet.

61. The apparatus of claim 52, further comprising an absorbing layer.

62. The apparatus of claim 61, wherein the absorbing layer is a fluid absorbing layer.

63. The apparatus of claim 52, wherein the light-guiding layer is a fluid light-guiding layer.

64. The apparatus of claim 63, further comprising a wall layer contacting the fluid light-guiding layer.

65. The apparatus of claim 64, wherein the wall layer is a cladding layer having a refractive index which is smaller than the second refractive index.

66. The apparatus of claim 64, wherein the wall layer is an additional light-guiding layer having a refractive index which is about the same as or greater than the second refractive index.

67. The apparatus of claim 63, wherein the coupling droplet is at least partially in the fluid light-guiding layer.

68. The apparatus of claim 52, wherein a thickness of the cladding fluid layer varies throughout the layer.

69. The apparatus of claim 52, wherein the light-guiding structure is curved.

70. The apparatus of claim 52, further comprising one or more lenses configured to focus the incident light.

71. The apparatus of claim 70, a focal plane of at least one of the one or more lenses being curved, wherein the light-guiding structure lies along the curved focal plane of the at least one of the one or more lenses.