CRYSTALLINE COLOR-CONVERSION DEVICE

• US 20180041005A1
• Filed: 10/16/2017
• Published: 02/08/2018
• Est. Priority Date: 06/09/2015
• Status: Active Grant

• Current Assignee: X Display Company Technology Limited (Sensinnovat BVBA)
• Original Assignee: X-Celeprint Limited
• Inventors: Bower, Christopher, Meitl, Matthew, Cok, Ronald S.
• Granted Patent: US 10,164,404 B2
• Time in Patent Office: Days
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 2933/0041 relating to wavelength conversion elements
• CPC Class Codes: H01L 33/502 Wavelength conversion materials
• CPC Class Codes: H01L 33/505 characterised by the shape, e.g. plate or foil
• CPC Class Codes: H01L 33/507 the elements being in intimate contact with parts other than the semiconductor body or integrated with parts other than the semiconductor body
• CPC Class Codes: H01L 33/508 having a non-uniform spatial arrangement or non-uniform concentration, e.g. patterned wavelength conversion layer, wavelength conversion layer with a concentration gradient of the wavelength conversion material
• CPC Class Codes: H01S 3/0915 by incoherent light
• CPC Class Codes: H01S 5/02257 using windows, e.g. specially adapted for back-reflecting light to a detector inside the housing
• CPC Class Codes: H01S 5/02326 Arrangements for relative positioning of laser diodes and optical components, e.g. grooves in the mount to fix optical fibres or lenses
• CPC Class Codes: H01S 5/02345 Wire-bonding
• CPC Class Codes: H01S 5/041 Optical pumping
• CPC Class Codes: H01S 5/32 comprising PN junctions, e.g. hetero- or double- heterostructures H01S5/34, H01S5/36 take precedence
• CPC Class Codes: H01S 5/32341 blue laser based on GaN or GaP
• CPC Class Codes: H01S 5/4025 Array arrangements, e.g. constituted by discrete laser diodes or laser bar H01S5/42 takes precedence

Abstract

According to an embodiment, a crystalline color-conversion device includes an electrically driven first light emitter, for example a blue or ultraviolet LED, for emitting light having a first energy in response to an electrical signal. An inorganic solid single-crystal direct-bandgap second light emitter having a bandgap of a second energy less than the first energy is provided in association with the first light emitter. The second light emitter is electrically isolated from, located in optical association with, and physically connected to the first light emitter so that in response to the electrical signal the first light emitter emits first light that is absorbed by the second light emitter and the second light emitter emits second light having a lower energy than the first energy.

Claims

1. A crystalline color-conversion device, comprising:

an electrically driven first light emitter for emitting first light having a first energy in response to an electrical signal; and

an inorganic solid single-crystal direct-bandgap second light emitter having a bandgap of a second energy less than the first energy,

wherein the second light emitter is electrically isolated from the first light emitter, is located in optical association with the first light emitter, and is located within 0 to 250 microns of the first light emitter so that in response to the electrical signal the first light emitter emits first light that is absorbed by the second light emitter and the second light emitter emits second light having a lower energy than the first energy.

2. The crystalline color-conversion device of claim 1, wherein the second light emitter has a composition different from the first light emitter.

3. The crystalline color-conversion device of claim 1 or 2, wherein the first light emitter is an inorganic solid single-crystal direct bandgap light emitter.

4. The crystalline color-conversion device of claim 3, wherein the crystal lattice structure of the first light emitter is different from the crystal lattice structure of the second light emitter.

5. The crystalline color-conversion device of claim 3, wherein the first light emitter is a light-emitting diode, a laser, or a vertical-cavity surface-emitting laser (VCSEL).

6. The crystalline color-conversion device of any one of claims 1 to 5, wherein the first light emitter is in physical contact with the second light emitter.

7. The crystalline color-conversion device of any one of claims 1 to 6, comprising a material that is at least partially transparent to the color of light emitted by the first light emitter and is located between and in contact with the first light emitter and the second light emitter.

8. The crystalline color-conversion device of claim 7, wherein the material is plastic, is an adhesive, is a curable adhesive, is a resin, or is a curable resin, or wherein the material is a dielectric stack that is an optical filter.

9. The crystalline color-conversion device of any one of claims 1 to 8, wherein the second light emitter is at least one of InGaN, bulk or quasi-bulk InGaN, InGaP, InGaAl phosphide, devoid of arsenic, devoid of cadmium, and devoid of rare earths.

10. The crystalline color-conversion device of any one of claims 1 to 9, wherein the second light emitter emits second light that has a peak wavelength of 460 nm or less.

11. The crystalline color-conversion device of any one of claims 1 to 10, comprising a plurality of first light emitters and a corresponding plurality of second light emitters.

12. The crystalline color-conversion device of claim 11, wherein each of the plurality of first light emitters has a common material and crystal lattice structure.

13. The crystalline color-conversion device of claim 12, wherein each of the plurality of first light emitters emits blue or ultraviolet first light.

14. The crystalline color-conversion device of claim 11, wherein at least some of the plurality of second light emitters are different from others of the plurality of second light emitters.

15. The crystalline color-conversion device of claim 14, wherein at least one of the plurality of second light emitters emits second light that is red, green, blue, or infrared.

16. The crystalline color-conversion device of claim 15, wherein at least a first one of the plurality of second light emitters emits red light, a second one of the plurality of second light emitters emits green light, and a third one of the plurality of second light emitters emits blue light.

17. The crystalline color-conversion device of any one of claims 1 to 16, wherein the first light emitter emits white light.

18. The crystalline color-conversion device of any one of claims 1 to 17, wherein the first light emitter emits a third light of a third energy less than the second energy and the third light passes through the second light emitter.

19. The crystalline color-conversion device of any one of claims 1 to 18, wherein the second light emitter comprises at least one of surface passivation, atomic layer deposition surface passivation, light out-coupling structure, light-extraction structures, templated epitaxial structures, and holes.

20. The crystalline color-conversion device of any one of claims 1 to 19, wherein the second light emitter has a thickness large enough to convert substantially all incident first light from the first light emitter having an energy greater than the second energy to light of the second energy.

21. The crystalline color-conversion device of any one of claims 1 to 20, wherein the second light emitter has a thickness chosen to convert a pre-determined fraction of the incident first light having an energy greater than the second energy to light of the second energy.

22. The crystalline color-conversion device of claim 21, comprising an inorganic solid single-crystal direct-bandgap third light emitter having a bandgap of a third energy less than the first energy, the third light emitter located on a side of the second light emitter opposite the first light emitter.

23. The crystalline color-conversion device of any one of claims 1 to 22, wherein the second light emitter has at least a first portion having a first thickness and a second portion having a second thickness less than the first thickness, the first thickness large enough to convert substantially all incident first light having an energy greater than the second energy to light of the second energy and the second thickness small enough that a substantial amount of incident first light having an energy greater than the second energy is not converted to light of the second energy.

24. The crystalline color-conversion device of any one of claims 1 to 23, wherein the second light emitter comprises a cavity in which the first light emitter is disposed.

25. The crystalline color-conversion device of any one of claims 1 to 24, wherein the second light emitter comprises inorganic direct-bandgap crystals that are disposed on multiple sides of the first light emitter to partially surround the first light emitter.

26. The crystalline color-conversion device of any one of claims 1 to 25, comprising a plurality of first light emitters in optical association with the second light emitter.

27. The crystalline color-conversion device of any one of claims 1 to 26, comprising an inorganic solid single-crystal direct-bandgap third light emitter having a bandgap of a third energy less than the first energy and that is electrically isolated from the first light emitter.

28. The crystalline color-conversion device of claim 27, wherein the third light emitter is located in optical association with the first light emitter and is located within 0 to 250 microns of the first light emitter so that in response to the electrical signal the first light emitter emits first light that is absorbed by the third light emitter and the third light emitter emits third light having a lower energy than the first energy.

29. The crystalline color-conversion device of claim 27, wherein the third light emitter has a bandgap of a third energy less than the second energy, the third light emitter is located in optical association with the second light emitter, and is located within 0 to 250 microns of the second light emitter so that light emitted by the second light emitter is absorbed by the third light emitter and the third light emitter emits third light having a lower energy than the second energy.

30. The crystalline color-conversion device of any one of claims 1 to 29, comprising a reflective layer located at least partially over the first light emitter or the second light emitter, or both the first light emitter and the second light emitter, that reflects light emitted by the first or second light emitters in undesirable directions.

31. The crystalline color-conversion device of any one of claims 1 to 30, wherein the second light emitter is an optically pumped laser.

32. The crystalline color-conversion device of any one of claims 1 to 31, wherein the second light emitter comprises a light-extraction structure.

33. The crystalline color-conversion device of any one of claims 1 to 32, comprising an electrically connected electrostatic gate formed on, under, or over a near-edge region of the second light emitter.

34. The crystalline color-conversion device of any one of claims 1 to 33, wherein the second light emitter is a semiconductor heterostructure comprising two different semiconductor materials or structures.

35. The crystalline color-conversion device of claim 34, wherein the semiconductor heterostructure has a cladding layer at least partially surrounding an active photoluminescent layer, the cladding layer having an energy bandgap larger than the energy bandgap of the active photoluminescent layer.

36. The crystalline color-conversion device of claim 35, wherein the cladding layer has an energy bandgap larger than the energy bandgap of the first emitter or wherein the cladding layer has an energy bandgap equal to or less than the energy bandgap of the first emitter and a thickness that is less than the thickness of the photoluminescent layer.

37. The crystalline color-conversion device of any one of claims 1 to 36, wherein the second light emitter is less than or equal to two microns thick.

38. The crystalline color-conversion device of any one of claims 1 to 37, wherein the second light has a full width half max (FWHM) less than or equal to 50 nm.

39. The crystalline color-conversion device of any one of claims 1 to 38, wherein at least one of the first light emitter and second light emitter has a width from 2 to 5 μ

m, 5 to 10 μ

m, 10 to 20 μ

m, or 20 to 50 μ

m.

40. The crystalline color-conversion device of any one of claims 1 to 39, wherein at least one of the first light emitter and second light emitter has a length from 2 to 5 μ

m, 5 to 10 μ

m, 10 to 20 μ

m, or 20 to 50 μ

m.

41. The crystalline color-conversion device of any one of claims 1 to 40, wherein at least one of the first light emitter and second light emitter has with a height from 2 to 5 μ

m, 4 to 10 μ

m, 10 to 20 μ

m, or 20 to 50 μ

m.

42. The crystalline color-conversion device of any one of claims 1 to 41, comprising an optical filter disposed on a side of the second light emitter opposite the first light emitter to reflect light from the first light emitter and transmit light emitted from the second light emitter.

43. A crystalline color-conversion display, comprising:

a display substrate;

the plurality of first light emitters and corresponding plurality of second light emitters according to any one of claims 11 to 42 located on or over the display substrate and distributed over the display substrate.

44. The crystalline color-conversion display of claim 43, wherein the plurality of second light emitters are grouped into pixel groups, each pixel group comprising at least a red second light emitter emitting red light, a green second light emitter emitting green light, and a blue second light emitter emitting blue light.

45. The crystalline color-conversion display of claim 43 or 44, wherein each of the plurality of first light emitters has a common material and crystal lattice structure.

46. The crystalline color-conversion display of any one of claims 43 to 45, wherein the second light emitters are located between the first light emitters and the display substrate and the second light emitters emit light through the display substrate.

47. The crystalline color-conversion display of any one of claims 43 to 46, wherein the first light emitters are located between the second light emitters and the display substrate and the second light emitters emit light in a direction opposite the display substrate.

48. The crystalline color-conversion display of any one of claims 43 to 47, wherein the display substrate is a member selected from the group consisting of polymer, plastic, resin, polyimide, polyethylene naphthalate, polyethylene terephthalate, metal, metal foil, glass, a semiconductor, and sapphire.

49. The crystalline color-conversion display of any one of claims 43 to 48, wherein the display substrate has a transparency greater than or equal to 50%, 80%, 90%, or 95% for visible light.

50. A method of making a crystalline color-conversion device, comprising:

providing an electrically driven first light emitter for emitting first light having a first energy in response to an electrical signal;

providing an inorganic solid single-crystal direct-bandgap second light emitter having a bandgap of a second energy less than the first energy; and

micro transfer printing the second light emitter onto the first light emitter or micro transfer printing the first light emitter onto the second light emitter, wherein the second light emitter is electrically isolated from the first light emitter, is located in optical association with the first light emitter, and is located within 0 to 250 microns of the first light emitter so that in response to the electrical signal the first light emitter emits first light that is absorbed by the second light emitter and the second light emitter emits second light having a lower energy than the first energy.

51. The method of claim 50, wherein the first and second light emitters form a light-emitting conversion structure and comprising micro-transfer printing the light-emitting conversion structure onto a display substrate.

52. The method of claim 50, comprising forming an inorganic solid single-crystal direct-bandgap layer on a source substrate and disposing the first light emitters onto the layer.

53. The method of claim 52, comprising etching the layer to form a plurality of spatially separated crystalline color-conversion devices on the source substrate.

54. The method of claim 53, comprising micro transfer printing the crystalline color-conversion devices from the source substrate to a display substrate.

55. The method of claim 50, comprising providing an inorganic solid single-crystal direct-bandgap source substrate and disposing the first light emitters onto the layer.

56. The method of claim 55, comprising etching the layer to form a plurality of spatially separated crystalline color-conversion devices.

57. The method of claim 56, comprising micro transfer printing the crystalline color-conversion devices from the source substrate to a display substrate.