PHOTOVOLTAICS WITH INTERFEROMETRIC RIBBON MASKS

• US 20090151771A1
• Filed: 12/17/2008
• Published: 06/18/2009
• Est. Priority Date: 12/17/2007
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Khazeni, Kasra, Kothari, Manish
• Granted Patent: US 8,193,441 B2
• Time in Patent Office: Days
• US Class Current: 136/246
• CPC Class Codes: G02B 26/001 based on interference in an adjustable optical cavity interference filters G02B5/28; devices or arrangements using multiple reflections in spectrometry or monochromators G01J3/26
• CPC Class Codes: G02B 5/284 of etalon type comprising a resonant cavity other than a thin solid film, e.g. gas, air, solid plates etalons for fibre optic multiplexing G02B6/29358; etalons for spectral measurement G01J3/26
• CPC Class Codes: H01L 31/02168 the coatings being antireflective or having enhancing optical properties for the solar cells
• CPC Class Codes: H01L 31/022425 for solar cells
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy

Abstract

An interferometric mask covering a reflective conductive ribbon that electrically interconnects a plurality of photovoltaic cells is disclosed. Such an interferometric mask may reduce reflections of incident light from the conductors. In various embodiments, the mask reduces reflections, so that a front and back electrode pattern appears black or similar in color to surrounding features of the device. In other embodiments, the mask may modulate reflections of light such that the electrode pattern matches a color in the visible spectrum.

Claims

1. A ribbon for a photovoltaic device, comprising:

an elongated conductor configured to electrically connect a plurality of photovoltaic cells, the conductor having a reflective surface;

an optical resonant cavity layer disposed on the reflective surface of the conductor; and

an absorber layer, wherein the absorber layer is disposed on the optical resonant cavity layer,

wherein the optical resonant cavity and the absorber layer are configured to interferometrically reduce reflections from the conductor.

2. The ribbon of claim 1, wherein the reflective surface is defined by a metallic reflective layer deposited over a ribbon conductive layer.

3. The ribbon of claim 2, wherein the metallic reflective layer is disposed between the optical resonant cavity layer and the conductor.

4. The ribbon of claim 2, wherein the reflective layer is disposed on one side of the ribbon conductive layer.

5. The ribbon of claim 2, wherein the reflective surface is disposed on upper and lower sides of the ribbon conductive layer.

6. The ribbon of claim 1, wherein the reflective surface is defined by a surface of a single conductive layer forming the conductor surface of the conductor.

7. The ribbon of claim 1, wherein the optical resonant cavity and the absorber layer are disposed on one side of the conductor.

8. The ribbon of claim 1, wherein the optical resonant cavity and the absorber layer are disposed on both sides of the conductor.

9. The ribbon of claim 8, wherein the optical resonant cavity and the absorber layer surround the conductor.

10. The ribbon of claim 9, wherein the optical resonant cavity layer and the absorber layer are made of a conductive material.

11. The ribbon of claim 1, wherein the optical resonant cavity layer and the absorber layer are configured such that a color of light reflected from the conductor substantially matches a color of surrounding features on the photovoltaic device.

12. The ribbon of claim 11, wherein the optical resonant cavity layer and the absorber layer are configured such that the color of light reflected from the conductor substantially matches a color in the visible spectrum.

13. The ribbon of claim 1, wherein the light reflected from the conductor falls within the wavelengths associated with the visible spectrum.

14. The ribbon of claim 1, wherein the optical resonant cavity layer and the absorber layer are configured such that little or no incident visible light is reflected from the conductor such that the ribbon appears black from a normal viewing angle.

15. The ribbon of claim 1, wherein the optical resonant cavity layer and the absorber layer are configured such that the reflectivity in the visible range from the conductor is less than 10%.

16. The ribbon of claim 1, further comprising:

a display;

a processor that is configured to communicate with said display, said processor being configured to process image data; and

a memory device that is configured to communicate with said processor.

17. The ribbon of claim 16, further comprising:

a driver circuit configured to send at least one signal to said display.

18. The ribbon of claim 17, further comprising:

a controller configured to send at least a portion of said image data to said driver circuit.

19. A photovoltaic device comprising:

means for generating an electrical current from incident light on a side of said means;

means for masking reflected light from said electrical current generating means; and

means for aligning and interconnecting a plurality of electrical current cells with said electrical current generating means.

20. The device of claim 19, wherein the means for generating an electrical current comprises an elongated conductor.

21. The device of claim 20, wherein the means for masking reflected light from said electrical current generating means comprises interferometric mask layers disposed over the elongated conductor, wherein the interferometric mask layers comprise an optical resonant cavity and an absorber layer.

22. A method of interconnecting a plurality of photovoltaic cells, comprising:

aligning a ribbon conductor along a plurality of photovoltaic cells, wherein the ribbon conductor comprises a conductive layer, an optical resonant cavity over the conductive layer, and an absorber layer over the optical resonant cavity; and

attaching the ribbon conductor along the plurality of photovoltaic cells such that the ribbon conductor is operatively coupled to the photovoltaic cells and the photovoltaic cells are electrically interconnected.

23. The method of claim 22, further comprising providing the ribbon conductor with stress-relief bends.

24. The method of claim 22, wherein attaching the ribbon conductor comprises using an adhesive layer.

25. The method of claim 24, wherein the adhesive layer comprises solder.

26. The method of claim 22, wherein the photovoltaic cells have a plurality of at least one of front electrodes, back electrodes, and contacts.

27. The method of claim 26, wherein the ribbon conductor connects the plurality of at least one of the front electrodes, back electrodes, and contacts through insulating material.

28. The method of claim 22, wherein the optical resonant cavity layer and the absorber layer are made of a conductive material.

29. The method of claim 22, wherein the optical resonant cavity layer and the absorber layer are configured such that a color of light reflected from the conductor substantially matches a color of surrounding features on the photovoltaic device.

30. The method of claim 29, wherein the optical resonant cavity layer and the absorber layer are configured such that the color of light reflected from the conductor substantially matches a color in the visible spectrum.

31. The method of claim 22, wherein the light reflected from the conductor falls within the wavelengths associated with the visible spectrum.

32. The method of claim 22, wherein the optical resonant cavity layer and the absorber layer are configured such that little or no incident visible light is reflected from the conductor such that the ribbon appears black from a normal viewing angle.

33. The method of claim 22, wherein the optical resonant cavity layer and the absorber layer are configured such that the reflectivity in the visible range from the conductor is less than 10%.

34. A method of making a ribbon conductor for a photovoltaic device, comprising:

providing a conductive strip; and

coating the conductive strip with a plurality of layers, wherein the layers form an optical resonant cavity over the conductive strip and an optical absorber layer over the optical resonant cavity, to define an interferometric modulator mask.

35. The method of claim 34, wherein the conductive strip is coated on both sides.

36. The method of claim 34, wherein the interferometric modulator mask is configured to interferometrically reduce visible reflectivity from the conductive strip to less than 10%.

37. The method of claim 34, wherein the optical resonant cavity and absorber layer are formed with a conductive material.

38. The method of claim 37, wherein the optical resonant cavity is formed with at least one of ITO and ZnO.

39. The method of claim 37, wherein the absorber layer is formed from at least one of Mo, Cr, MoCr, and Ti.

40. The method of claim 34, further comprising a reflective layer disposed between the optical resonant cavity and the conductive strip.

41. The method of claim 34, coating the conductive strip comprises:

providing a substrate having interferometric mask layers, wherein the interferometric mask layers comprise an optical resonant cavity and an absorber layer;

subsequently laminating the substrate having the interferometric mask layers onto the conductive strip; and

removing the substrate from the interferometric mask layers after lamination on the conductive strip.

42. A system for converting optical energy to electrical energy comprising:

a plurality of photovoltaic cells;

a conductor layer electrically connecting the plurality of photovoltaic cells; and

a plurality of layers forming an optical interferometric modulator mask over the conductor layer, wherein the mask is configured to mask reflections from the conductor layer.

43. The system of claim 42, further comprising an adhesive material configured for joining the conductor layer and optical interferometric modulator mask with the plurality of photovoltaic cells.

44. The system of claim 43, wherein the adhesive material comprises solder.

45. The system of claim 42, wherein the optical interferometric modulator mask is configured to appear black.

46. The system of claim 42, wherein the optical interferometric modulator mask is configured to reduce visible reflectivity over the conductor layer to less than 10%.

47. The system of claim 42, wherein the optical interferometric modulator mask is configured to match a visible color of surrounding structures.

48. The system of claim 42, wherein the plurality of layers defines an optical resonant cavity layer;

and an absorber layer thereover.

49. The system of claim 48, wherein the plurality of layers further comprises a reflective mirror layer between the optical resonant cavity layer and the conductive layer.

50. The system of claim 48, wherein the optical resonant cavity comprises a dielectric layer.

51. The system of claim 48, wherein the optical resonant cavity comprises an optically transparent conductive layer.

52. The system of claim 48, wherein the optical resonant cavity comprises a plurality of layers.

53. The system of claim 48, wherein the optical resonant cavity is disposed along both a front side and a back side of the conductor layer such that the optical resonant cavity substantially surrounds the conductor layer.

54. The system of claim 48, wherein the absorber layer comprises a conductive semitransparent thickness of a metallic material.

55. The system of claim 54, wherein the metallic material is selected from the group consisting of Cr, Mo, MoCr, and Ti.