Lighting devices using feedback enhanced light emitting diode

• US 7,335,921 B2
• Filed: 05/08/2003
• Issued: 02/26/2008
• Est. Priority Date: 05/08/2002
• Status: Expired due to Fees

• Current Assignee: MT Technology Enterprises, LLC
• Original Assignee: Zeolux Corporation
• Inventors: Magn, John N., Koch, Gene C.
• Primary Examiner(s): Vo; Tuyet Thi
• Application Number:
  US10/431,885
• Publication Number:
  US 20040066824A1
• Time in Patent Office: 1,755 Days
• Field of Search: 257/80, 257/84, 257/79, 257/103, 315/169.3, 315/169.4
• US Class Current: 257/80
• CPC Class Codes: G09G 3/2803 Display of gradations G09G3/288 takes precedence
• CPC Class Codes: G09G 3/32 semiconductive, e.g. using light-emitting diodes [LED]
• CPC Class Codes: H01L 33/465 with a resonant cavity structure
• CPC Class Codes: H01S 3/08059 Constructional details of the reflector, e.g. shape mirrors in general G02B5/08; mountings for mirrors G02B7/18
• CPC Class Codes: H01S 3/1065 using liquid crystals
• CPC Class Codes: H01S 3/1686 Liquid crystal active layer
• CPC Class Codes: H01S 5/183 having only vertical cavities, e.g. vertical cavity surface-emitting lasers [VCSEL]
• CPC Class Codes: H01S 5/36 comprising organic materials
• CPC Class Codes: H10K 2102/3031 Two-side emission, e.g. transparent OLEDs [TOLED]
• CPC Class Codes: H10K 50/816 Multilayers, e.g. transparent multilayers
• CPC Class Codes: H10K 50/828 Transparent cathodes, e.g. comprising thin metal layers
• CPC Class Codes: H10K 50/8426 Peripheral sealing arrangements, e.g. adhesives, sealants
• CPC Class Codes: H10K 50/85 Arrangements for extracting light from the devices
• CPC Class Codes: H10K 50/852 comprising a resonant cavity structure, e.g. Bragg reflector pair
• CPC Class Codes: H10K 50/856 comprising reflective means
• CPC Class Codes: H10K 50/858 comprising refractive means, e.g. lenses
• CPC Class Codes: H10K 50/86 Arrangements for improving contrast, e.g. preventing reflection of ambient light
• CPC Class Codes: H10K 59/12 Active-matrix OLED [AMOLED] displays
• CPC Class Codes: H10K 59/1201 Manufacture or treatment
• CPC Class Codes: H10K 59/1213 the pixel elements being TFTs
• CPC Class Codes: H10K 59/17 : Passive-matrix OLED displays
• CPC Class Codes: H10K 59/35 : comprising red-green-blue [RGB] subpixels
• CPC Class Codes: H10K 59/65 : OLEDs integrated with inorganic image sensors
• CPC Class Codes: H10K 71/00 : Manufacture or treatment specially adapted for the organic devices covered by this subclass

Abstract

Lighting devices using feedback-enhanced luminescent devices are disclosed. A light emitting diode disposed between feedback elements (FE-LED) may be used as a light emitting element in the lighting devices. The light emitting element may be coupled to a light distribution element. In one aspect, the light emitting diode may be an organic light emitting diode (FE-OLED).

Claims

1. A lighting device comprising:

a light source comprising at least;

a first feedback layer adapted to receive and reflect light;

a first electrode formed on the first feedback layer;

one or more semiconducting layers formed over the first electrode, at least one of the one or more semi-conducting layers comprising luminescent material;

a second electrode disposed over the one or more semiconducting layers; and

a second feedback layer adapted to receive and reflect light disposed over the second electrode; and

;

a light distribution element disposed adjacent to one or both of the first feedback layer and the second feedback layer and adapted to distribute light emitted therefrom,

wherein the first feedback layer or the second feedback layer or both the first feedback layer and the second feedback layer comprise at least a layer with a photonic crystal structure.

2. The device of claim 1, wherein the light distribution element is attached to the light source.

3. The device of claim 1, wherein the light distribution element is located immediately adjacent to the light source.

4. The device of claim 1, wherein the light distribution element comprises a diffuser for diffusing the light emitted from the light source.

5. The device of claim 1, wherein the light source and the light distribution element are shaped substantially flat and elongated.

6. The device of claim 1, wherein the light source and the light distribution element are bonded directly to one another.

7. The device of claim 1, wherein the device is adapted to be attached to a wall or ceiling or both.

8. The device of claim 1, wherein the device comprises a plurality of light distribution elements.

9. The device of claim 1, wherein the photonic crystal structure includes one-dimensional, two-dimensional, or three-dimensional photonic crystal structures or combinations thereof.

10. The device of claim 1, wherein the light distribution element comprises a light diverging screen.

11. The device of claim 5, wherein the light diverging screen comprises a plurality of tapered light guides.

12. The device of claim 1, further comprising:

a housing having at least one opening, the light source mounted in the housing and disposed to emit light substantially in the direction of the opening, and the light distribution element mounted in the housing and disposed between the light source and the opening for distributing the light towards the opening.

13. The device of claim 2, further comprising:

a second light distribution element mounted in the housing between the opening and the light distribution element.

14. The device of claim 7, wherein the second light distribution element is mounted as to cover the opening of the housing.

15. The device of claim 12, wherein the light distribution element comprises a light diverging screen.

16. The device of claim 15, wherein the light diverging screen comprises a plurality of tapered light guides.

17. A lighting device comprising:

a light source comprising at least;

a first feedback layer adapted to receive and reflect light;

a first electrode formed on the first feedback layer;

one or more semiconducting layers formed over the first electrode, at least one of the one or more semi-conducting layers comprising luminescent material;

a second electrode disposed over the one or more semiconducting layers; and

a second feedback layer adapted to receive and reflect light disposed over the second electrode; and

;

a light distribution element disposed adjacent to one or both of the first feedback layer and the second feedback layer and adapted to distribute light emitted therefrom,

wherein the first feedback layer or the second feedback layer or both the first feedback layer and the second feedback layer comprise at least a layer of holographic recording material.

18. The device of claim 17, wherein the light distribution element is integral with the light source.

19. The device of claim 17, wherein the light source further comprises a hole injection layer disposed between the first feedback layer and the one or more semiconducting layers.

20. The device of claim 17, wherein the light source further comprises an electron injection layer disposed between the second feedback layer and the one or more semiconducting layers.

21. The device of claim 17, wherein the light source further comprises a hole transport layer disposed between the hole injection layer and the one or more semiconducting layers.

22. The device of claim 17, wherein the light source further comprises an electron transport layer disposed between the electron injection layer and the one or more semiconducting layers.

23. The device of claim 17, wherein the luminescent material comprises pure material, a solid solution, an alloy, or inhomogeneous mixture, or combination thereof.

24. The device of claim 17, wherein the luminescent material comprises a polymer luminescent material.

25. The device of claim 17, wherein the luminescent material comprises a cross-linked organic luminescent material.

26. The device of claim 17, wherein the luminescent material comprises a luminescent material comprising molecules having molecular weight range between that of a small molecule to a polymer.

27. The device of claim 17, wherein the luminescent material comprises a small molecule luminescent material dissolved in a polymer host.

28. The device of claim 17, wherein the luminescent material comprises a fluorescent material.

29. The device of claim 17, wherein the luminescent material comprises a phosphorescent material.

30. The device of claim 17, wherein the luminescent material comprises an organic and inorganic composite luminescent material.

31. The device of claim 17, wherein the luminescent material comprises an inorganic luminescent material.

32. The device of claim 17, wherein the luminescent material comprises a liquid crystalline material.

33. The device of claim 17, further comprising a substrate over which the first feedback layer is disposed.

34. The device of claim 33, wherein the substrate comprises a glass substrate.

35. The device of claim 33, wherein the substrate comprises one or more of a flexible plastic substrate, a metal substrate, a semiconductor material.

36. A lighting device comprising:

a light source comprising at least;

a first feedback layer adapted to receive and reflect light;

a first electrode formed on the first feedback layer;

one or more semiconducting layers formed over the first electrode, at least one of the one or more semi-conducting layers comprising luminescent material;

a second eledctrode disposed over the one or more semiconducting layers; and

a second feedback layer adapted to receive and reflect light disposed over the second electrode; and

;

a light distribution element disposed adjacent to one or both of the first feedback layer and the second feedback layer and adapted to distribute light emitted therefrom.

wherein the first feedback layer or the second feedback layer or both the first feedback layer and the second feedback layer comprise at least a layer of material having a plane wave interference pattern.

37. The device of claim 36, wherein one or more of the feedback layers of material comprise at least a layer of holographic recording material.

38. The device of claim 36, wherein one or more of the feedback layers of material comprise at least a layer of photonic crystal material.

39. A light device comprising:

a light source comprising at least;

a first feedback layer adapted to receive and reflect light;

a first electrode formed on the first feedback layer;

one or more semiconducting layers formed over the first electrode, at least one of the one or more semi-conducting layers comprising luminescent material;

a second electrode disposed over the one or more semiconducting layers; and

a second feedback layer adapted to receive and reflect light disposed over the second electrode; and

;

a light distribution element disposed adjacent to one or both of the first feedback layer and the second feedback layer and adapted to distribute light emitted therefrom.

wherein the first feedback layer or the second feedback layer or both the first feedback layer and the second feedback layer comprise at least a layer of material having plane wave interference patterns corresponding to different wavelengths of light.

40. The device of claim 39, wherein one or more of the feedback layers of material comprise at least a layer of holographic recording material.

41. The device of claim 39, wherein one or more of the feedback layers of material comprise at least a layer of photonic crystal material.

42. The device of claim 39, wherein the plane wave interference patterns corresponding to each wavelength of light are respectively confined to separate geometrically shaped domains or areas in a plane of the layer of material.

43. The device of claim 42, wherein the geometrically shaped areas comprise parallel stripes.

44. The device of claim 42, wherein the separate geometrically shaped domains or areas in the first feedback layer of material have substantially a same geometrical shape and occupy substantially a same location in a plane of the second feedback layer of material.

45. A lightinh device comprising:

a light source comprising at least;

a first feedback layer adapted to receive and reflect light;

a first electrode formed on the first feedback layer;

one or more semiconducting layers formed over the first electrode, at least one of the one or more semi-conducting layers comprising luminescent material;

a second electrode disposed over the one or more semiconducting layers; and

a second feedback layer adapted to receive and reflect light disposed over the second electrode; and

;

a light distribution element disposed adjacent to one or both of the first feedback layer and the second feedback layer and adapted to distribute light emitted therefrom,

wherein the layer of luminescent material comprises two or more luminescent materials each separately patterned into geometrically shaped domains or areas in a plane of the luminescent material.

46. The device of claim 45, wherein the geometrically shaped domains or areas in the plane of the luminescent materials have substantially a same shape and occupy substantially a same location in the plane as the first feedback layer or the second feedback layer or both the first feedback layer and the second feedback layer.

47. The device of claim 46, wherein each of the luminescent materials has a spectral emission band that substantially overlaps a reflection bands of the interference patterns in the corresponding domains or areas in the first feedback layer or the second feedback layer or both the first feedback layer and the second feedback layer.

48. The device of claim 47, wherein one or more of the luminescent materials has a broad spectral band emission that can be used in the domains or areas of the luminescent material located corresponding to domains or areas in the first feedback layer or the second feedback layer or both the first feedback layer and the second feedback layer that have plane wave interference patterns corresponding to different wavelengths of light.

49. A lighting device comprising:

a light source comprising at least;

a first feedback layer adapted to receive and reflect light;

a first electrode formed on the first feedback layer;

one or more semiconducting layers formed over the first electrode, at least one of the one or more semi-conducting layers comprising luminescent material;

a second electrode disposed over the one or more semiconducting layers; and

a second feedback layer adapted to receive and reflect light disposed over the second electrode; and

;

a light distributing element disposed adjacent to one or both of the first feedback layer and the second feedback layer and adapted to distribute light emitted therefrom,

wherein a distance between the first feedback layer and the second feedback layer is in an order of approximately one half-wavelength of emitted light.

50. A lighting device comprising:

a light source comprising at least;

a first feedback layer adapted to receive and reflect light;

one or more semiconducting layers formed over the first electrode, at least one of the one or more semi-conducting layers comprising luminescent material;

a second electrode disposed over the one or more semiconducting layers; and

a second feedback layer adapted to receive and reflect light disposed over the second electrode; and

;

a light distribution element disposed adjacent to one or both of the first feedback layer and the second feedback layer and adapted to distribute light emitted therefrom,

wherein a distance between the first feedback layer and the second feedback layer is an order of approximately two or more half-wavelengths of emitted light.

51. A lighting device comprising:

a light source comprising at least;

a first feedback layer adapted to receive and reflect light;

a first electrode formed on the first feedback layer;

one or more semiconducting layers formed over the first electrode, at least one of the one or more semi-conducting layers comprising luminescent material;

a second electrode disposed over the one or more semiconducting layers; and

a second electrode feedback layer adapted to receive and reflect light disposed over the second electrode; and

;

a light distribution element disposed adjacent to one or both of the first feedback layer and the second feedback layer and adapted to distribute light emitted therefrom,

wherein the luminescent material comprises an electroluminescent material whose spectral emission band overlaps reflection bands of the first feedback layer and the second feedback layer.

52. A lighting device comprising:

a light source comprising at least;

a first feedback layer adapted to receive and reflect light;

a first electrode formed on the first feedback layer;

one or more semiconducting layers formed over the first electrode, at least one of the one or more semi-conducting layers comprising luminescent material;

a second electrode disposed over the one or more semiconducting layers; and

a second electrode feedback layer adapted to receive and reflect light disposed over the second electrode; and

;

a light distribution element dispoed adjacent to one or both of the first feedback layer and the second feedback layer and adapted to distribute light emitted therefrom,

wherein the first and the second electrodes, and the one or more semiconducting layers are formed in a defect in a continuous photonic crystal formed by the first feedback layer and the second feedback layer.

53. The device of claim 52, wherein the defect comprises a phase-slip in a spatial phase of the photonic crystal of less than one wavelength of emitted light.

54. The device of claim 52, wherein the light emitted from the layer of luminescent material emanates into a defect mode.

55. The device of claim 52, wherein the photonic crystal structure includes one-dimensional, two-dimensional, or three-dimensional photonic crystal structures or combinations thereof.

56. A lighting device comprising:

a light source comprising at least;

a first feedback layer adapted to receive and reflect light;

a first electrode formed on the first feedback layer;

one or more semiconducting layers formed over the first electrode, at least one of the one or more semi-conducting layers comprising luminescent material;

a second electrode disposed over the one or more semiconducting layers; and

a second feedback layer adapted to receive and reflect light disposed over the second electrode; and

;

a light distribution element disposed adjacent to one or both of the first feedback layer and the second feedback layer and adapted to distribute light emitted therefrom,

wherein both the first feedback layer and the second feedback layer transmit no light at a peak wavelength of their spectral reflection bands and the luminescent material radiates light into band-edge laser modes.

57. A lighting device comprising:

a light source comprising at least;

a first feedback layer adapted to receive and reflect light;

a first electrode formed on the first feedback layer;

one or more semiconducting layers formed over the first electrode, at least one of the one or more semi-conducting layers comprising luminescent material;

a second electrode disposed over the one or more semiconducting layers; and

a second feedback layer adapted to receive and reflect light disposed over the second electrode; and

;

a light distribution element disposed adjacent to one or both of the first feedback layer and the second feedback layer and adapted to distribute light emitted therefrom,

wherein one or both of the first feedback layer and the second feedback layer has a refractive index profile that at least in part varies periodically along an axis normal or substantially normal to a plane of a respective feedback layer.

58. The device of claim 57, wherein one or both of the first feedback layer and the second feedback layer that have periodically varying refractive index profiles have at least in part continuously varying refractive index profiles.

59. A lighting device comprising:

a light source comprising at least;

a first feedback layer adapted to receive and reflect light;

a first electrode formed on the first feedback layer;

one or more semiconducting layers formed over the first electrode, at least one of the one or more semi-conducting layers comprising luminescent material;

a second electrode disposed over the one or more semiconducting layers; and

a second feedback layer adaped to receive and reflect light disposed over the second electrode; and

;

a light distribution element disposed adjacent to one or both of the first feedback layer and the second feedback layer and adapted to distribute light emitted therefrom,

wherein a distance between the first feedback layer and the second feedback layer is such that the space between the feedback layers constitutes a cavity in which light of one or more desired wavelengths constructively interfere.

60. A lighting device comprising:

a light source comprising at least;

a first feedback layer adapted to receive and reflect light;

a first electrode formed on the first feedback layer;

one or more semiconducting layers formed over the first electrode, at least one of the one or more semiconducting layers comprising luminescent material;

a second electrode disposed over the one or more semiconducting layers; and

a second feedback layer adapted to receive and reflect light disposed over the second electrode; and

;

a light distribution element disposed adjacent to one or both of the first feedback layer and the second feedback layer and adapted to distribute light emitted therefrom,

wherein light reflected by one or both of the first feedback layer and the second feedback layer stimulates emission of light from the one or more layers of luminescent material.

61. The device of claim 60, wherein the stimulated emission of light results in substantial collimation of light emitted by the device.

62. The device of claim 60, wherein the stimulated emission of light results in laser action.

63. A lighting device comprising:

a light source comprising at least;

a first feedback layer adapted to receive and reflect light;

a first electrode formed on the first feedback layer;

one or more semiconducting layers formed over the first electrode, at least one of the one or more semi-conducting layers comprising luminescent material;

a second electrode disposed over the one or more semiconducting layers; and

a second feedback layer adapted to receive and reflect light disposed over the second electrode; and

;

a light distribution element disposed adjacent to one or both of the first feedback layer and the second feedback layer and adapted to distribute light emitted therefrom,

wherein all light emitted by the device occupies a single light propagation mode.

64. The device of claim 63, wherein spacing between the first feedback layer and the second feedback layer is equivalent to λ

/2 excluding phase shifts due to reflection, λ

being a wavelength of the light in the single light propagation mode.

65. A light device comprising;

a light source comprising at least;

a first feedback layer adapted to receive and reflect light;

a first electrode formed on the first feedback layer;

one or more semiconducting layers formed over the first electrode, at least one of the one or more semi-conducting layers comprising luminescent material;

a second electrode disposed over the one or more semiconducting layers; and

a second feedback layer adapted to receive and reflect light disposed over the second electrode;

a light distribution element disposed adjacent to one or both of the first feedback layer and the second feedback layer and adapted to distribute light emitted therefrom,

wherein light emitted by the device occupies two or more light propagation modes.

66. A lighting device comprising:

a light source comprising at least;

a first feedback layer adapted to receive and reflect light;

a first electrode formed on the first feedback layer;

one or more semiconducting layers formed over the first electrode, at least one of the one or more semi-conducting layers comprising luminescent material;

a second electrode disposed over the one or more semiconducting layers; and

a second feedback layer adapted to receive and reflect light disposed over the second electrode; and

;

a light distribution element disposed adjacent to one or both of the first feedback layer and the second feedback layer and adapted to distribute light emitted therefrom,

wherein one or both of the first feedback layer and the second feedback layer comprises refractive index profiles that have superimposed multiple periodic spatial frequencies of variation.