Shawn Paul Hill

US Patent:

20140210355, Jul 31, 2014

Filed:

Mar 27, 2014

Appl. No.:

14/227626

Inventors:

- Durham NC, US
Shawn Hill - Raleigh NC, US

Assignee:

Cree, Inc. - Durham NC

International Classification:

H05B 33/08

US Classification:

315151

Abstract:

A plurality of light-emitting devices (LEDs), included in at least a string, can include at least one first LED configured to emit first chromaticity light, at least one second LED configured to emit second chromaticity light, and at least one additional LED configured to emit additional chromaticity light, wherein the at least one string can be operated by modulating the first modulated LED segment and/or the at least one additional modulated LED segment based on respective specified chromaticity values of the plurality of LEDs to provide the light substantially in conformance with a Planckian locus. The chromaticity of the light emitted by the at least one string can b e measured to provide a measured chromaticity value and the modulation of the first modulated LED segment or the at least one additional modulated LED segment can be adjusted by a shift value based on a difference between the measured chromaticity value and a specified chromaticity value to provide an additional v′ shift in light toward the Planckian locus.

US Patent:

20140210364, Jul 31, 2014

Filed:

Mar 31, 2014

Appl. No.:

14/230651

Inventors:

- Durham NC, US
Shawn Hill - Raleigh NC, US

Assignee:

Cree, Inc. - Durham NC

International Classification:

H05B 33/08

US Classification:

315186

Abstract:

A solid state lighting apparatus can include a plurality of light-emitting devices (LEDs) that are electrically coupled together in at least one string. The apparatus can further include a first LED segment that is configured to emit a first chromaticity light coupled across a first bypass circuit, a second LED segment that is configured to emit a second chromaticity light coupled across a second bypass circuit, and at least one additional LED segment that is configured to emit an additional chromaticity light coupled across a respective at least one additional bypass circuit. A control circuit can be configured to modulate the at least one additional bypass circuit, to cause the lighting apparatus to emit an additional v′ shift in a chromaticity value of light emitted by the string to vary substantially in conformance with a Planckian locus in response to a dimming input to the control circuit.