Color tuning of light-emitting devices

• US 10,811,576 B2
• Filed: 03/14/2014
• Issued: 10/20/2020
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Quarkstar LLC
• Original Assignee: Quarkstar LLC
• Inventors: Stormberg, Hans Peter, Haitz, Roland H., Schinagl, Ferdinand
• Primary Examiner(s): Warren, Matthew E
• Application Number:
  US14/776,402
• Publication Number:
  US 20160035949A1
• Time in Patent Office: 2,412 Days
• CPC Class Codes: F21Y 2113/17 forming a single encapsulated light source
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 25/167 comprising optoelectronic devices, e.g. LED, photodiodes
• 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 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 2933/0091 Scattering means in or on the semiconductor body or semiconductor body package H01L33/22 takes precedence
• 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 33/50 Wavelength conversion elements
• CPC Class Codes: H01L 33/502 Wavelength conversion materials
• CPC Class Codes: H01L 33/504 Elements with two or more wavelength conversion materials
• CPC Class Codes: H01L 33/58 Optical field-shaping elements
• CPC Class Codes: H01L 33/60 Reflective elements
• 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

A variety of light-emitting devices for general illumination utilizing solid state light sources (e.g., light-emitting diodes) are disclosed. A light-emitting device can include a first light-emitting element (LEE) for emitting light having a first spectral composition, a second LEE for emitting light having a second spectral composition, and a scattering element surrounding at least in part the first and second LEEs to scatter light emitted from the first and second LEEs. The light-emitting device can also include electrical connections for connecting the first and second LEEs to a power source, where the electrical connections are arranged such that power to the first LEE is separately adjustable relative to power to the second LEE.

Claims

1. A light-emitting device, comprising:

a substrate having a first surface;

a plurality of blue pump light-emitting elements (LEEs) disposed on the first surface;

a scattering element surrounding, at least in part, the plurality of blue pump LEEs, the scattering element comprising inelastic scattering centers arranged to scatter light from the plurality of blue pump LEEs, wherein the scattering element includes a plurality of segments, the segments arranged over subsets of blue pump LEEs of the plurality of blue pump LEEs, such that a projection of each segment onto a plane defined by the substrate overlaps at least in part with a projection onto the plane of the blue pump LEEs in the corresponding subset of blue pump LEEs, and

each subset of blue pump LEEs comprises

a first blue pump LEE that is common among all the subsets such that the projection onto the plane of the first blue pump LEE partially overlaps with the projection onto the plane of each of the segments, and

a second blue pump LEE that is different from second blue pump LEEs of adjacent subsets, such that the projection onto the plane of the second blue pump LEE overlaps with the projection onto the plane of a respective one of the segments, and

each of the segments is configured to provide light having one of two or more spectral compositions; and

electrical connections for connecting the plurality of blue pump LEEs to a power source, the electrical connections being arranged such that power to a blue pump LEE of the plurality of blue pump LEEs is separately adjustable relative to power to another blue pump LEE of the plurality of blue pump LEEs.

2. The light-emitting device of claim 1, wherein the electrical connections are arranged such that power to at least one blue pump LEE of the plurality of blue pump LEEs that correspond to at least one of the segments is separately adjustable relative to power to at least one other blue pump LEE of the plurality of blue pump LEEs that correspond to another segment.

3. The light-emitting device of claim 1, wherein each segment of the plurality of segments comprises a phosphor layer that provides light with a corresponding correlated color temperature.

4. The light-emitting device of claim 1, wherein each segment of the plurality of segments comprises a phosphor layer that provides light with a corresponding chromaticity.

5. The light-emitting device of claim 1, further comprising a sensor arranged to receive a fraction of light output by the scattering element, the sensor being configured to provide a sensor signal based on the fraction of light, wherein the sensor is in communication with a control circuit configured to control power provided to at least some of the plurality of blue pump LEEs.

6. The light-emitting device of claim 5, wherein the light-emitting device includes the control circuit.

7. The light-emitting device of claim 5, wherein the sensor signal is configured to provide an indication of an intensity of the light output by the scattering element.

8. The light-emitting device of claim 5, wherein the sensor signal is configured to provide an indication of a spectral density distribution of the light output by the scattering element.

9. The light-emitting device of claim 1, further comprising a non-photonic sensor.

10. The light-emitting device of claim 9, wherein the non-photonic sensor includes at least one of a temperature detector and a voltage detector.

11. The light-emitting device of claim 1, wherein the scattering element has a dome shape.

12. The light-emitting device of claim 1, wherein at least a portion of the first surface is a diffusely reflective surface.

13. The light-emitting device of claim 1, wherein at least a portion of the first surface is a specularly reflective surface.

14. The light-emitting device of claim 1, wherein the scattering element is spaced apart from the plurality of blue pump LEEs and coupled to the substrate to form an enclosure, the scattering element having an input surface facing the plurality of blue pump LEEs and an output surface opposing the input surface.

15. The light-emitting device of claim 14, wherein at least a portion of the substrate forms a cup.

16. The light-emitting device of claim 14, wherein the substrate is flat.

17. The light-emitting device of claim 14, wherein an index of refraction of the scattering element is larger than an index of refraction of a medium in the enclosure and larger than an index of refraction of an ambient environment.

18. The light-emitting device of claim 1, further comprising a light guide and wherein light output by the scattering element is coupled into the light guide.

19. The light-emitting device of claim 1, further comprising an extractor element coupled to an output surface of the scattering element.

20. The light-emitting device of claim 19, further comprising a light guide and wherein light output from the extractor element is coupled into the light guide.

21. The light-emitting device of claim 19, further comprising a light guide and wherein the extractor element is coupled to the light guide.

22. The light-emitting device of claim 19, wherein an index of refraction of the scattering element is larger than an index of refraction of the extractor element such that an acceptance angle for rays of light within the scattering element at the output surface is larger than an acceptance angle at an input surface of the scattering element.

23. The light-emitting device of claim 19, wherein an index of refraction of the scattering element is equal or smaller than an index of refraction of the extractor element.

24. The light-emitting device of claim 19, wherein the scattering element is spaced apart from the plurality of blue pump LEEs and coupled to the substrate to form an enclosure, and wherein an index of refraction of the scattering element is larger than an index of refraction of a medium in the enclosure.

25. The light-emitting device of claim 19, wherein the extractor element has a transparent exit surface opposing the output surface of the scattering element that is shaped such that an angle of incidence on the exit surface of the light provided by the scattering element that directly impinges on the exit surface is less than a critical angle for total internal reflection at the exit surface.

26. The light-emitting device of claim 19, wherein the scattering element is a coating applied to a surface of the extractor element.