Chromaticity control for solid-state illumination sources
AssigneeDolby Laboratories Licensing Corporation
InventorsRobin Atkins, Vincent Kwong, Chun Chi Wan
Life of this patent
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Abstract
Chromaticity of light output by a light-emitting diode, such as a light-emitting diode (LED), is adjusted while maintaining a brightness of the illumination source substantially constant by adjusting a drive schema for the illumination source. A driver for LEDs or other light-emitting diodes provides for varying a drive schema to adjust chromaticity of driven LEDs.
Claims26
Apparatus for driving a light-emitting diode, the apparatus comprising:
- a driving circuit configured to control a driving current in the light-emitting diode according to a driving schema and a control value to cause the light-emitting diode to emit light having a brightness determined by the control value and a chromaticity determined by the driving schema, the driving schema specifying one or more characteristics of the driving current;
- and,
- a control circuit configured to alter the driving schema to alter the chromaticity of the light emitted by the light-emitting diode without changing the brightness of the emitted light, wherein altering the driving schema comprises changing from a first driving schema to a second driving schema so as to produce a change in an overall spectral composition of the light emitted by the light-emitting diode.
A display comprising:
- a plurality of light-emitting diodes;
- a driving circuit configured to control a driving current in each of the light-emitting diodes according to a corresponding driving schema, a corresponding control value to cause the light-emitting diode to emit light having a brightness determined by the control value and a chromaticity determined by the corresponding driving schema;
- and
- a control circuit configured to alter the driving schema corresponding to one or more of the light-emitting diodes to alter chromaticity of the light emitted by the one or more light-emitting diodes without changing the brightnesses of the light emitted by the one or more of the light-emitting diodes, wherein altering the driving schema comprises changing from a first driving schema to a second driving schema so as to produce a change in an overall spectral composition of the light emitted by the one or more light-emitting diodes.
A method for controlling a light-emitting diode, the method comprising controlling a driving current in the light-emitting diode according to a driving schema and a control value to cause the light-emitting diode to emit light having a brightness determined by the control value and a chromaticity determined by the driving schema, the driving schema specifying one or more characteristics of the driving current;
- and,
- altering the driving schema to alter the chromaticity of the emitted light while maintaining the brightness of the emitted light substantially unchanged, wherein altering the driving schema comprises changing from a first driving schema to a second driving schema so as to produce a change in an overall spectral composition of the light emitted by the light-emitting diode.
A LED driver unit for driving a plurality of light-emitting diodes, the driver unit comprising:
- a plurality of driving circuits each having an input for receiving a control value and an output connectible to a light-emitting diode to be driven,
- for each of the driving circuits an independently-variable stored driving schema specifying one or more characteristics of the driving current;
- wherein the driver circuits are each configured to control a driving current in the light-emitting diode according to the corresponding driving schema and the corresponding control value to cause the light-emitting diode to emit light having a brightness determined by the control value and a chromaticity determined by the driving schema and the driving circuit is configured to alter the driving schema for one or more of the driver circuits to cause a change in the chromaticity of light emitted by the corresponding light-emitting diode to be driven without affecting the brightness determined by the control value, so as to produce a change in an overall spectral composition of the light emitted by the corresponding light-emitting diode to be driven.
Dependencies are inferred from the claim text.