High-efficiency radiating device

• US 20050110033A1
• Filed: 10/15/2004
• Published: 05/26/2005
• Est. Priority Date: 07/28/1998
• Status: Active Grant

• Current Assignee: Signify Holding B.V. (Signify N.V.)
• Original Assignee: IMEC International, Vrije Universiteit Brussel
• Inventors: Windisch, Reiner, Borghs, Gustaaf, Kuijk, Maarten, Heremans, Paul
• Granted Patent: US 7,253,445 B2
• Time in Patent Office: Days
• US Class Current: 257/98
• CPC Class Codes: H01L 33/025 Physical imperfections, e.g. particular concentration or distribution of impurities
• CPC Class Codes: H01L 33/08 with a plurality of light emitting regions, e.g. laterally discontinuous light emitting layer or photoluminescent region integrated within the semiconductor body H01L27/15 takes precedence
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector

Abstract

A device emits radiation at a predetermined wavelength. The device includes a light-emitting diode (LED) which generates the radiation. The device further includes at least one edge having a substantially random diffraction grating structure in radiative communication with the LED.

Claims

1. A device for emitting radiation at a predetermined wavelength, the device comprising:

a light-emitting diode (LED) which generates the radiation; and

at least one edge having a substantially random diffraction grating structure which is in radiative communication with the LED.

2. The device of claim 1, wherein the substantially random diffraction grating structure is a regular repetition of a random grating.

3. The device of claim 1, further comprising a waveguide which is in radiative communication with the Led.

4. The device of claim 3, wherein the edge having a substantially random diffraction grating structure is coextensive with at least one edge of the waveguide.

5. The device of claim 4, wherein the edge having a substantially random diffraction grating structure abuts or extends in the LED.

6. The device of claim 1, wherein the LED is mounted on a carrier substrate which is transparent to the radiation.

7. The device of claim 6, wherein the carrier substrate comprises a fiber optic face plate.

8. The device of claim 1, wherein the substantially random diffraction grating structure has a plurality of differently spaced ridges and valleys.

9. The device of claim 1, wherein the edge having a substantially random diffraction grating structure is mirrored.

10. A device for emitting radiation at a predetermined wavelength, the device comprising:

a light-emitting diode (LED) which generates the radiation; and

at least two edges forming in cross-section a substantially triangular shape and an angle between the edges being smaller than about 45 degrees, wherein at least one of the edges has a portion which is transparent to the radiation, and at least one of the edges has a substantially random diffraction grating structure which is in radiative communication with the LED.

11. The device of claim 10, wherein one of the two edges is transparent to the radiation and one of the two edges is reflective to the radiation, and wherein the edges are adjacent to one another or abutting one another.

12. The device of claim 11, wherein at least one of the two edges has a roughened surface condition.

13. An array of devices for emitting radiation at a predetermined wavelength, each device comprising:

a light-emitting diode (LED) which generates the radiation; and

at least one edge having a substantially random diffraction grating structure which is in radiative communication with the LED, wherein the devices of the array are individually controllable.

14. The array of claim 13, wherein each device of the array is defined by a mesa edge, and wherein a plurality of grooves are positioned between adjacent devices, wherein the grooves have a substantially random diffraction grating structure.

15. The array of claim 13, wherein the devices have a common anode contact and a common cathode contact.

16. The array of claim 13, wherein substantially all of the devices have a microlens mounted thereon.

17. The array of claim 13, wherein the array is mounted on a polymeric foil carrier.

18. The array of claim 17, wherein the polymeric foil carrier has a radiation-converting phosphorous layer thereon, each device having a first side mounted to the polymeric foil carrier and a second side opposite to the first side, each device emitting radiation of a first wavelength at the first side and emitting radiation of a second wavelength at the second side.

19. The array of claim 13, wherein each device further comprises a waveguide which is in radiative communication with the LED.

20. A device for emitting radiation at a predetermined wavelength, the device comprising:

a light-emitting diode (LED) which generates the radiation;

at least one edge having a substantially random diffraction grating structure in radiative communication with the LED; and

a transparent carrier, the LED mounted on the transparent carrier.

21. A device for emitting radiation at a predetermined wavelength, the device comprising:

a light-emitting diode (LED) which generates the radiation;

at least one edge having a substantially random diffraction grating structure in radiative communication with the LED;

at least one reflective edge in radiative communication with the LED; and

at least one electrical contact to the LED, the contact extending through the reflective edge.

22. The device of claim 21, wherein the substantially random diffraction grating structure is a regular repetition of a random grating.

23. The device of claim 21, further comprising a waveguide which is in radiative communication with the LED.

24. The device of claim 23, wherein the edge having a substantially random diffraction grating structure is coextensive with at least one edge of the waveguide.

25. The device of claim 24, wherein the edge having a substantially random diffraction grating structure abuts or extends in the LED.

26. The device of claim 21, wherein the LED is mounted on a carrier substrate which is transparent to the radiation.

27. The device of claim 26, wherein the carrier substrate comprises a fiber optic face plate.

28. The device of claim 21, wherein the substantially random diffraction grating structure has a plurality of differently spaced ridges and valleys.

29. The device of claim 21, wherein the edge having a substantially random diffraction grating structure is mirrored.

30. The device of claim 21, further comprising a transparent carrier, wherein the LED is mounted on the transparant carrier.

31. An array of devices for emitting radiation at a predetermined wavelength, each device comprising:

a light-emitting diode (LED) which generates the radiation; and

a plurality of waveguides positioned between the devices, whereby the waveguides have a substantially random diffraction grating structure in radiative communication with the LED, and wherein the devices are individually controllable.

32. A light-emitting diode (LED) for emitting radiation at a predetermined wavelength, the LED comprising:

an active layer which generates the radiation; and

a substantially random diffraction grating structure in radiative communication with the active layer.

33. The LED of claim 32, further comprising a mesa structure in radiative communication with the active layer, wherein the mesa structure is positioned so as to reflect radiation towards the substantially random diffraction grating structure.