Lighting system having reduced melanopic spectral content

• US 10,113,700 B2
• Filed: 09/12/2017
• Issued: 10/30/2018
• Est. Priority Date: 09/12/2016
• Status: Active Grant

• Current Assignee: Lumileds LLC (Apollo Global Management, Inc.)
• Original Assignee: Lumileds LLC (Apollo Global Management, Inc.)
• Inventors: Soer, Wouter A., Shchekin, Oleg B., Bechtel, Hans-Helmut
• Primary Examiner(s): Santiago, Mariceli
• Application Number:
  US15/702,152
• Publication Number:
  US 20180073689A1
• Time in Patent Office: 413 Days
• CPC Class Codes: A61M 2021/0044 by the sight sense
• CPC Class Codes: A61M 21/00 Other devices or methods to cause a change in the state of consciousness; Devices for producing or ending sleep by mechanical, optical, or acoustical means, e.g. for hypnosis
• CPC Class Codes: C09K 11/77347 Silicon Nitrides or Silicon Oxynitrides
• CPC Class Codes: C09K 11/77348 Silicon Aluminium Nitrides or Silicon Aluminium Oxynitrides
• CPC Class Codes: F21K 9/64 using wavelength conversion means distinct or spaced from the light-generating element, e.g. a remote phosphor layer
• 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: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H01L 27/156 two-dimensional arrays
• 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: H05B 45/20 Controlling the colour of the light
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

A disclosed light-emitting device may provide white light with a cyan gap coinciding with a melanopic sensitivity range and thus having reduced melanopic content. The disclosed light-emitting device may include a light source providing violet or blue light with a peak wavelength under 450 nanometers (nm). The disclosed light-emitting device may include at least one down-converter coupled to and located downstream of the light source and configured with a long-wavelength onset to convert the spectrum of the violet or blue light to generate white light with a spectral power content in a 447-531 nm wavelength range that is less than or equal to 10% of a total spectral power content in a 380-780 nm wavelength range. The disclosed light-emitting device may be incorporated in a light engine system that further includes a control system that controls a drive current to the light-emitting device.

Claims

1. A light-emitting device configured to provide white light with a cyan gap coinciding with a melanopic sensitivity range, the light-emitting device comprising:

a light source configured to provide violet or blue light with a peak wavelength under 450 nanometers (nm); and

at least one down-converter coupled to and located downstream of the light source and configured with a long-wavelength onset to convert a spectrum of the violet or blue light to generate the white light with a correlated color temperature (CCT) greater than or equal to 2700 Kelvin (K) and with a spectral power content in a 447-531 nm wavelength range that is less than or equal to 10% of a total spectral power content in a 380-780 nm wavelength range.

2. The light-emitting device of claim 1, wherein the light source is configured to provide the violet or blue light with the peak wavelength between 410 nm and 420 nm.

3. The light-emitting device of claim 1, wherein the light source is configured to provide the violet or blue light with the peak wavelength between 420 nm and 430 nm.

4. The light-emitting device of claim 1, wherein the light source is configured to provide the violet or blue light with the peak wavelength between 430 nm and 440 nm.

5. The light-emitting device of claim 1, wherein the light source is configured to provide the violet or blue light with the peak wavelength between 440 nm and 450 nm.

6. The light-emitting device of claim 1, wherein the light source is configured as a short-wavelength pump phosphor-converted light-emitting diode (pc-LED).

7. The light-emitting device of claim 6, wherein the pc-LED is a high-power flip-chip die.

8. The light-emitting device of claim 7, wherein the at least one down-converter is a ceramic plate attached to the high-power flip-chip die.

9. The light-emitting device of claim 1, wherein the at least one down-converter is a nitride-based phosphor system with peak emission in an amber wavelength range.

10. The light-emitting device of claim 9, wherein the nitride-based phosphor system is made from at least one of the following materials:

(Ba,Sr)₂Si₅N₈;

Eu (BSSN) or (Sr,Ca)SiAIN₃;

Eu (SCASN).

11. The light-emitting device of claim 1, wherein the at least one down-converter is a phosphor coating.

12. The light-emitting device of claim 1, wherein the at least one down-converter is a quantum dot converter.

13. The light-emitting device of claim 1, wherein the at least one down-converter comprises a luminescent material that absorbs at least a part of the violet or blue light.

14. The light-emitting device of claim 1, wherein the at least one down-converter comprises a luminescent material that transmits at least a part of the violet or blue light.

15. The light-emitting device of claim 1, wherein the at least one down-converter is configured to provide a yellow light so that the light-emitting devices provides a broader combined emission spectrum extending into red light.

16. The light-emitting device of claim 1, wherein the at least one down-converter is in contact with a light emitting surface of the light source.

17. The light-emitting device of claim 1, wherein the at least one down-converter is located at a non-zero distance from a light emitting surface of the light source.

18. The light-emitting device of claim 1 implemented in a light engine that further includes a control system that controls a drive current to the light-emitting device.

19. A light engine configured to provide white light with tunable spectral content in a range coinciding with a melanopic sensitivity range, the light engine comprising:

a plurality of light-emitting devices, each of the plurality of light-emitting devices comprising;

a light source configured to provide violet or blue light with a peak wavelength under 450 nanometers (nm); and

at least one down-converter coupled to and located downstream of the light source and configured with a long-wavelength onset to convert a spectrum of the violet or blue light to generate the white light with a spectral power content in a 447-531 nm wavelength range that is less than or equal to 10% of a total spectral power content in a 380-780 nm wavelength range; and

a control system configured to control drive current to the plurality of light-emitting devices.