Light emitting devices including narrowband converters for outdoor lighting applications
AssigneeCree, Inc.
InventorsLinjia Mu, Kenneth Lotito, Ryan Gresback
Life of this patent
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Abstract
A light emitting device includes a light emitting diode (“LED”), a first luminescent material that is configured to emit light having an emission peak in a green wavelength range, and a second luminescent material that is configured to emit narrow-spectrum light having an emission peak in an orange wavelength range. A light output of the light emitting device, which includes a portion of the light emitted by the LED, the light having the emission peak in the green wavelength range, and the light having the emission peak in the orange wavelength range, provides an appearance of white light. Related devices are also discussed.
Claims18
A light emitting device, comprising:
- at least one light emitting diode (“LED”);
- at least one first luminescent material that is configured to emit light having an emission peak in a wavelength range of 495 nanometers (nm) to 565 nm, responsive to light emitted by the at least one LED;
- and
- a second luminescent material that is configured to emit narrow-spectrum light having an emission peak in a wavelength range of 580 nm to 609 nm, responsive to light emitted by the at least one LED;
- wherein the light emitting device is configured to provide light output that includes a portion of the light emitted by the at least one LED, the light emitted by the first luminescent material, and the light emitted by the second luminescent material, and the light emitting device is free of broad-spectrum luminescent materials that are configured to emit light having an emission peak in a red wavelength range;
- and
- wherein the light output of the light emitting device has a color rendering index (CRI) of no greater than about 75.
A light emitting device, comprising:
- a light emitting diode (“LED”);
- at least one broad-spectrum luminescent material;
- and
- at least one narrow-spectrum luminescent material that is configured to absorb a portion of light generated by the LED and responsively emit light having an emission peak in an orange wavelength range,
- wherein the light emitting device is free of broad-spectrum luminescent materials that are configured to emit light having an emission peak in a red wavelength range;
- wherein the light emitting device is configured to provide light output that includes a portion of the light emitted by the LED, light emitted by the at least one broad-spectrum luminescent material, and the light emitted by the at least one narrow-spectrum luminescent material, and has a color rendering index (CRI) in a range of from about 50 to about 75;
- and
- wherein the at least one narrow-spectrum luminescent material comprises first and second narrow-spectrum luminescent materials that are configured to absorb first and second portions of the light emitted by the LED and emit light having emission peaks in orange and green wavelength ranges, respectively.
Dependencies are inferred from the claim text.