VARIABLE-BEAM LIGHT SOURCE AND RELATED METHODS

• US 20150009677A1
• Filed: 07/09/2014
• Published: 01/08/2015
• Est. Priority Date: 09/24/2012
• Status: Active Grant

• Current Assignee: LEDVANCE LLC (MLS Co. Ltd.)
• Original Assignee: TerraLUX Incorporated
• Inventors: Catalano, Anthony W.
• Granted Patent: US 9,470,406 B2
• Time in Patent Office: Days
• US Class Current: 362/296.07
• CPC Class Codes: F21S 10/00 Lighting devices or systems producing a varying lighting effect
• CPC Class Codes: F21V 23/003 the elements being electronics drivers or controllers for operating the light source, e.g. for a LED array
• CPC Class Codes: F21V 23/04 the elements being switches safety devices F21V25/00
• CPC Class Codes: F21V 7/0091 using total internal reflection
• CPC Class Codes: F21V 7/045 with spherical surface
• CPC Class Codes: F21V 7/048 with facets structure
• CPC Class Codes: F21V 7/06 with parabolic curvature
• CPC Class Codes: F21Y 2105/10 comprising a two-dimensional array of point-like light-generating elements
• CPC Class Codes: F21Y 2105/12 characterised by the geometrical disposition of the light-generating elements, e.g. arranging light-generating elements in differing patterns or densities
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H01L 2224/45015 being circular
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48464 the other connecting portion not on the bonding area also being a ball bond, i.e. ball-to-ball
• CPC Class Codes: H01L 24/24 of an individual high density interconnect connector
• CPC Class Codes: H01L 24/45 of an individual wire connector
• CPC Class Codes: H01L 24/48 of an individual wire connector
• CPC Class Codes: H01L 24/73 Means for bonding being of different types provided for in two or more of groups H01L24/10, H01L24/18, H01L24/26, H01L24/34, H01L24/42, H01L24/50, H01L24/63, H01L24/71
• CPC Class Codes: H01L 27/156 two-dimensional arrays
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 : the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/12042 : LASER
• CPC Class Codes: H01L 2924/207 : Diameter ranges
• CPC Class Codes: H01L 33/0041 : characterised by field-effect operation
• CPC Class Codes: H01L 33/0093 : Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/30 : containing only elements of Group III and Group V of the Periodic Table
• CPC Class Codes: H01L 33/62 : Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls
• CPC Class Codes: H05B 45/10 : Controlling the intensity of the light

Abstract

Light sources with arrangements of multiple LEDs (or other light-emitting devices) disposed at or near the focus of a reflecting optic having multiple segments facilitate varying the angular distribution of the light beam (e.g., the beam divergence) via the drive currents supplied to the LEDs.

Claims

1. A light source producing a beam of variable divergence, comprising:

a plurality of light-emitting devices arranged on a plane;

a concave reflecting optic having an axis of symmetry and comprising a plurality of segments, each having an aiming angle with respect to the axis of symmetry, for redirecting light emitted thereon, light emitted by the light-emitting devices and reflected by the optic forming a light beam; and

driver circuitry for controlling drive currents to the light-emitting devices individually or in groups thereof to thereby variably control a divergence of the light beam;

wherein at least some of the segments have different aiming angles depending on their distances from the plane of the light-emitting devices.

2. The light source of claim 1, wherein the aiming angle of each segment with respect to the axis of symmetry increases gradually as the distance between the segment and the plane of the light-emitting devices decreases.

3. The light source of claim 2, wherein the reflecting optic comprises first and second edge segments having a shortest distance and a longest distance, respectively, from the plane of the light-emitting devices, the first edge segment having a first aiming angle approximately equal to a desired divergence angle of the light beam and the second edge segment having a second aiming angle approximately parallel to the axis of symmetry for collimating the light beam.

4. The light source of claim 1, wherein the reflecting optic comprises two regions, segments in a first region having relatively large aiming angles with respect to the axis of symmetry for providing divergence of the light beam and segments in a second region having relatively small aiming angles with respect to the axis of symmetry for collimating the light beam.

5. The light source of claim 1, wherein the segments are parabolic and the light-emitting devices are disposed substantially at a focus of the parabolic segments.

6. The light source of claim 1, wherein the light-emitting devices are arranged in a pattern having a center, the driver circuitry being configured to control the drive currents to the light-emitting devices based on their distances from the center.

7. The light source of claim 1, wherein the driver circuitry is configured to narrow the beam by providing non-zero drive currents only to light-emitting devices within a specified distance from the center.

8. The light source of claim 1, wherein the light-emitting devices are arranged in a pattern having a center region and an outer region outside the center region, the driver circuitry being configured to decrease the drive currents to the light-emitting devices located in the center region to thereby increase a divergence angle of the beam.

9. The light source of claim 8, wherein the driver circuitry is configured to decrease the drive currents to the light-emitting devices located in the outer region to thereby narrow the beam.

10. The light source of claim 1, wherein the driver circuitry is configured to selectively drive a subset of the light-emitting devices so as to generate a pattern.

11. The light source of claim 1, wherein the driver circuitry is programmable.

12. The light source of claim 1, wherein an area density of the light-emitting devices is uniform.

13. The light source of claim 1, wherein the light-emitting devices are arranged symmetrically.

14. The light source of claim 13, wherein the arrangement of the light-emitting devices is circularly symmetric or radially symmetric.

15. The light source of claim 13, wherein the light-emitting devices are arranged in a pattern having a center region and an outer region outside the center region such that none of the light-emitting devices is located in the center region.

16. The light source of claim 1, wherein the driver circuitry is configured to control the drive currents based on at least one of sizes or positions of respective light-emitting devices.

17. The light source of claim 1, wherein the light-emitting devices are arranged in a pattern having a center region and an outer region outside the center region, light-emitting devices located in the center region being higher-power devices than light-emitting devices located in the outer region.

18. The light source of claim 1, wherein the light-emitting devices comprise LEDs.

19. The light source of claim 18, wherein the LEDs are disposed on a single substrate having a plurality of electrical contacts.

20. The light source of claim 19, wherein the substrate comprises a semiconductor material.

21. A method of varying a divergence of a light source comprising (i) a plurality of light-emitting devices arranged on a plane and in a pattern having a center region and an outer region outside the center region, and (ii) a concave reflecting optic having an axis of symmetry and comprising a plurality of segments, each segment having an aiming angle with respect to the axis of symmetry for redirecting light emitted thereon, at least some of the segments having different aiming angles depending on their distances from the plane of the light-emitting devices, the method comprising:

driving the light-emitting devices to create a light beam emerging from the reflecting optic; and

controlling drive currents to the light-emitting devices, individually or in groups thereof, based on distances of the devices from center region so that the beam has a divergence variably determined by, at least in part, the controlled drive currents.

22. The method of claim 21, wherein the aiming angle of each segment with respect to the axis of symmetry increases gradually as the distance between the segment and the plane of the light-emitting devices decreases.

23. The method of claim 22, wherein the reflecting optic comprises first and second edge segments having a shortest distance and a longest distance, respectively, from the plane of the light-emitting devices, the first edge segment having a first aiming angle approximately equal to a desired divergence angle of the light beam and the second edge segment having a second aiming angle approximately parallel to the axis of symmetry for collimating the light beam.

24. The method of claim 21, wherein the reflecting optic comprises two regions, segments in a first region having relatively large aiming angles with respect to the axis of symmetry for providing divergence of the light beam and segments in a second region having relatively small aiming angles with respect to the axis of symmetry for collimating the light beam.

25. The method of claim 21, wherein the segments are parabolic and the light-emitting devices are disposed substantially at a focus of the parabolic segments.

26. The method of claim 21, wherein an area density of the light-emitting devices is uniform.

27. The method of claim 21, wherein the light-emitting devices are arranged symmetrically.

28. The method of claim 27, wherein the arrangement of the light-emitting devices is circularly symmetric or radially symmetric.

29. The method of claim 27, wherein the light-emitting devices are arranged in a pattern having a center region and an outer region outside the center region such that none of the light-emitting devices is located in the center region.

30. The method of claim 21, wherein the light-emitting devices comprise LEDs.

31. The method of claim 30, wherein the LEDs are disposed on a single substrate having a plurality of electrical contacts.

32. The method of claim 31, wherein the substrate comprises a semiconductor material.

33. The method of claim 21, wherein controlling the drive currents comprises decreasing the drive currents to the light-emitting devices in an outer region thereof to thereby narrow the beam.

34. The method of claim 21, wherein the light-emitting devices are arranged in a pattern having a center region and an outer region outside the center region, the step of controlling the drive currents comprising decreasing the drive currents to the light-emitting devices in a center region thereof to thereby increase a divergence angle of the beam.

35. The method of claim 21, further comprising simultaneously and uniformly varying the drive currents to all LEDs to thereby vary the beam brightness.

36. A light system comprising:

a single substrate having a plurality of electric contacts;

disposed on the substrate, a light-emitting array comprising a plurality of light-emitting diodes (LEDs); and

a plurality of conducting traces, each connecting one of the LEDs to one of the electric contacts,

wherein at least one of the contacts is embedded within the substrate.

37. The device of claim 36, wherein the substrate comprises a semiconductor material.

38. The device of claim 37, wherein the contacts comprise ion-implanted regions.

39. The device of claim 36, wherein the substrate comprises an insulating material.

40. The device of claim 36, wherein anodes of the LEDs in a row array are connected via a first set of conducting lines and cathodes of the LEDs in a column array are connected via a second set of conducting lines.

41. The device of claim 36, further comprising a plurality of field-effect transistors (FETs) each electrically connected to an LED via one of the contacts.

42. The device of claim 41, wherein source terminals of the FETs in a row array are connected via a first set of conducting lines, gate terminals of the FETs in a column array are connected via a second set of conducting lines, drain terminals are connected to anodes of associated LEDs, and cathodes of the LEDs are connected to a common ground.

43. The device of claim 41, wherein the FETs are embedded in the substrate.

44. The device of claim 41, further comprising a controller for selectively activating or deactivating various ones of the LEDs via the associated FETs to achieve a desired pattern.

45. The device of claim 36, wherein the LED dies comprise a group III-V semiconductor material.

46. The device of claim 44, wherein the substrate comprises silicon.

47. A method of fabricating a light system comprising:

forming a plurality of electric contacts on a substrate, at least one of the contacts being embedded therewithin;

forming a plurality of LED dies on the substrate; and

interconnecting the LED dies with the electric contacts to form a light-emitting array.

48. The method of claim 47, wherein the substrate is made of a semiconductor material and the electric contacts are at least partially formed by ion implantation.

49. The method of claim 47, wherein anodes of the LED dies in a row array are connected via a first set of conducting lines and cathodes of the LED dies in a column array are connected via a second set of conducting lines.

50. The method of claim 47, further comprising connecting a field-effect transistor (FET) to each of the plurality of LED dies.

51. The method of claim 50, wherein source terminals of the FETs in a row array are connected via a first set of conducting lines, gate terminals of the FETs in a column array are connected via a second set of conducting lines, drain terminals are connected to anodes of associated LED dies, and cathodes of the LED dies are connected to a common ground.

52. The method of claim 50, wherein the FETs are embedded in the substrate.

53. The method of claim 50, further comprising selectively activating or deactivating various ones of the LED dies via the associated FETs to achieve a desired pattern.

54. The method of claim 47, further comprising bonding a layer of III-V semiconductor material to the substrate prior to forming the plurality of LED dies, the plurality of LED dies being formed at least partially within the layer of III-V semiconductor material.

55. The method of claim 47, wherein forming the plurality of LED dies comprises (i) forming the plurality of LED dies on a second substrate, (ii) removing the plurality of LED dies from the second substrate, and (iii) bonding the plurality of LED dies to the substrate.