LED structure with a dynamic spectrum and a method
View Patent ↗An integrated LED structure and a method of adjusting the emission spectrum of an integrated LED structure, for photobiological process. The structure comprises a substrate; a plurality of optically isolated and electrically non-independent light emission areas integrated on the substrate; a light emitting semiconductor source of a first type mounted in the emission area(s); a light emitting semiconductor source of a second type mounted in the emission area(s); an electrical circuit layer for connecting the said light emitting semiconductor sources in serial fashion for each emission area; and wavelength conversion materials. The emission areas are controlled with a common electrical drive current, and the emission output can be tuned by adjusting the common current value, to enable use of one luminaire for a large variety of biomass growing applications.
1. A light emitting structure, comprising:
a substrate;
a first light emission area and a second light emission area integrated on the substrate;
a first light emitting semiconductor source mounted in the first light emission area;
a second light emitting semiconductor source mounted in the second light emission area;
an electrical circuit layer configured to serially connect the first and second light emitting semiconductor sources, such that the first and second light emitting semiconductor sources are controllable by a common drive current to cause the first light emitting semiconductor source to emit at a peak of a first wavelength and to cause the second light emitting semiconductor source to emit at a peak of a second wavelength different from the first wavelength;
a first wavelength conversion layer in the first light emission area and formed on the first light emitting semiconductor source, wherein the first wavelength conversion material is configured to emit at a peak of a third wavelength; and
a second wavelength conversion layer in the second light emission area and formed on the second light emitting semiconductor source, wherein the second wavelength conversion material is configured to emit at a peak of a fourth wavelength different from the third wavelength.
2. The light emitting structure of claim 1 , wherein the first light emission area and the second light emission area respectively comprise first and second cavities in the substrate.
3. The light emitting structure of claim 1 , wherein the first light emission area and the second light emission area are arranged on a top surface of the substrate.
4. The light emitting structure of claim 3 , wherein the first light emission area and the second light emission area are optically isolated from each other by an opaque structure formed on the top of the substrate.
5. The light emitting structure of claim 3 , wherein the electrical circuit layer is formed on the top surface of the substrate.
6. The light emitting structure of claim 1 , further comprising a polarizer covering at least one of the first light emission area or the second light emission area.
7. The light emitting structure of claim 1 , wherein the first and second light emitting semiconductor sources have different current-to-light conversion characteristics.
8. The light emitting structure of claim 1 , wherein the first light emitting semiconductor source comprises a vertical semiconductor diode, and wherein the second light emitting semiconductor source comprises a sapphire based semiconductor diode.
9. The light emitting structure of claim 1 , wherein the third wavelength is between 620 and 640 nm, and wherein the fourth wavelength is between 650 and 670 nm.
10. The light emitting structure of claim 1 , wherein the first and second wavelengths are between 365 to 440 nm.
11. The light emitting structure of claim 1 , wherein the light emitting structure is configured to produce an emission spectrum in response to the common drive current, the emission spectrum comprising a peak at the third wavelength and a peak at the fourth wavelength.
12. The light emitting structure of claim 11 , wherein the peak at the third wavelength in the emission spectrum is configured to excite chlorophyll B, and wherein the peak at the fourth wavelength in the emission spectrum is configured to excite chlorophyll A.
13. The light emitting structure of claim 11 , further comprising an electrical control interface configured to supply the common drive current, wherein the electrical control interface is configured to adjust a magnitude of the common drive current between a first value and a second value.
14. The light emitting structure of claim 13 , wherein at the first value a ratio of an intensity of the peak at the third wavelength in the emission spectrum and an intensity of the peak at the fourth wavelength in the emission spectrum is a first ratio, and wherein at the second value a ratio of the intensity of the peak at the third wavelength in the emission spectrum and the intensity of the peak at the fourth wavelength in the emission spectrum is a second ratio different from the first ratio.
15. The light emitting structure of claim 1 , further comprising an electrical control interface configured to supply the common drive current as a pulsed current.
16. The light emitting structure of claim 1 , wherein the first and second light emission areas are optically isolated from each other.
17. A light emitting structure, comprising:
a substrate;
a first light emission area and a second light emission area integrated on the substrate, wherein the first and second light emission areas are optically isolated from each other;
a first light emitting semiconductor source mounted in the first light emission area;
a second light emitting semiconductor source mounted in the second light emission area;
an electrical circuit layer configured to serially connect the first and second light emitting semiconductor sources, such that the first and second light emitting semiconductor sources are controllable by a common drive current to cause the first and second light emitting semiconductor sources to emit;
a first wavelength conversion layer in the first light emission area and formed on the first light emitting semiconductor source, wherein the first wavelength conversion material is configured to emit at a peak of a first wavelength; and
a second wavelength conversion layer in the second light emission area and formed on the second light emitting semiconductor source, wherein the second wavelength conversion material is configured to emit at a peak of a second wavelength different from the first wavelength.
18. The light emitting structure of claim 17 , wherein the first light emission area and the second light emission area respectively comprise first and second cavities in the substrate.
19. The light emitting structure of claim 17 , wherein the first light emission area and the second light emission area are optically isolated from each other by an opaque structure formed on the top of the substrate.
20. The light emitting structure of claim 17 , wherein the first and second light emitting semiconductor sources have different current-to-light conversion characteristics.
21. The light emitting structure of claim 17 , wherein the first and second light emitting semiconductor sources are of different types.
22. The light emitting structure of claim 21 , wherein the first light emitting semiconductor source comprises a vertical semiconductor diode, and wherein the second light emitting semiconductor source comprises a sapphire based semiconductor diode.
23. The light emitting structure of claim 17 , wherein the first wavelength is between 620 and 640 nm, and wherein the second wavelength is between 650 and 670 nm.
24. The light emitting structure of claim 17 , wherein the light emitting structure is configured to produce an emission spectrum in response to the common drive current, the emission spectrum comprising a peak at the first wavelength and a peak at the second wavelength.
25. The light emitting structure of claim 24 , wherein the peak at the first wavelength in the emission spectrum is configured to excite chlorophyll B, and wherein the peak at the second wavelength in the emission spectrum is configured to excite chlorophyll A.
26. The light emitting structure of claim 24 , further comprising an electrical control interface configured to supply the common drive current, wherein the electrical control interface is configured to adjust a magnitude of the common drive current between a first value and a second value.
27. The light emitting structure of claim 26 , wherein at the first value a ratio of an intensity of the peak at the first wavelength in the emission spectrum and an intensity of the peak at the second wavelength in the emission spectrum is a first ratio, and wherein at the second value a ratio of the intensity of the peak at the first wavelength in the emission spectrum and the intensity of the peak at the second wavelength in the emission spectrum is a second ratio different from the first ratio.