LED wavelength-converting plate with microlenses
View Patent ↗A wavelength-converting plate for a wavelength-converted light emitting diode (LED) assembly. The wavelength-converting plate includes microlenses deposited thereon. The microlenses may have an index of refraction different from the index of refraction of the wavelength-converting plate. The microlenses on the top surface of the plate increase lumen output in a direction normal to the top surface of a wavelength-converting plate.
1. A light source comprising:
a light emitting diode (LED) configured to emit primary light from an emitting surface;
a wavelength-converting plate having a bottom surface in opposed facing relationship to said emitting surface of said LED, said wavelength-converting plate having a wavelength-converting material therein configured to emit secondary light in response to said primary light being imparted thereon; and
a plurality of microlenses deposited on said bottom surface of said wavelength-converting plate.
2. A light source according to claim 1 , wherein said microlenses have an index of refraction different from an index of refraction of said wavelength-converting plate.
3. A light source according to claim 1 , wherein said microlenses are further deposited on a top surface of said wavelength-converting plate.
4. A light source according to claim 1 , wherein said microlenses are deposited in a monolayer.
5. A light source according to claim 1 , wherein said microlenses are dome-shaped.
6. A light source according to claim 1 , wherein said microlenses are monospheres.
7. A wavelength-converting plate for a wavelength-converted light emitting diode (LED) assembly including an LED configured to emit primary light, said wavelength-converting plate comprising:
a top surface and a bottom surface, said bottom surface for positioning in opposed facing relationship to an emitting surface of the LED, and a wavelength-converting material configured to emit secondary light through the top surface in response to the primary light being imparted thereon; and
a plurality of microlenses deposited on said bottom surface of said wavelength-converting plate.
8. A wavelength-converting plate according to claim 7 , wherein said microlenses have an index of refraction different from an index of refraction of said wavelength-converting plate.
9. A wavelength-converting plate according to claim 7 , wherein said microlenses are further deposited on the top surface of said wavelength-converting plate and said microlenses on said top surface have an index of refraction between an index of refraction of said wavelength-converting plate and an index of refraction of a medium in contact said microlenses on said top surface.
10. A wavelength-converting plate according to claim 7 , wherein said microlenses are deposited in a monolayer.
11. A wavelength-converting plate according to claim 7 , wherein said microlenses are dome-shaped.
12. A wavelength-converting plate according to claim 7 , wherein said microlenses are monospheres.
13. A wavelength-converting plate according to claim 7 , wherein said microlenses are comprised of at least one of silica, a polymer, silicone, yttrium aluminum garnet (YAG), or alumina.
14. A wavelength-converting plate according to claim 13 wherein the polymer is polymethylmethacrylate (PMMA) or polystyrene (PS).
15. A wavelength-converting plate according to claim 7 , wherein said microlenses are monospherical having a diameter in a range of about 0.5 μm to 50.0 μm.
16. A wavelength-converting plate according to claim 15 , wherein said microlenses have a diameter in the range of about 0.5 μm to 1.0 μm.