Techniques for lumen maintenance and color shift compensation
First Claim
1. A lighting assembly, comprising:
- a diffusible light source to illuminate an area by providing light output, wherein the provided light output is measured in lumens;
a photo detector configured to measure lumen output of the diffusible light source and a golden sample light beam;
a directed light source to provide the golden sample light beam, wherein the golden sample light beam is used to calibrate the photo detector; and
a controller configured to determine a photo detector calibration factor based on a first lumen output measurement of the directed light source and a second lumen output measurement of the directed light source, the calibration factor indicative of photo detector degradation over a period of time between the first lumen output measurement and the second lumen output measurement.
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Accused Products
Abstract
Techniques are disclosed for maintaining consistent lumen output of a lighting assembly over time. By maintaining a consistent lumen output, it is possible to maintain acceptable color stability where color mixing of multiple outputs is used. The lighting assembly may be any lighting configuration that might suffer from lumen depreciation and/or color drift over time, and may include any type(s) of light source(s) that may be monitored and driven accordingly. The lighting assembly, in addition to light source(s), includes a photo detector and a directed light source, such as a laser. The directed light source provides a golden sample for use in calibrating the photo detector, which in turn monitors lumen output of the light source(s). Drive signals are adjusted to account for lumen depreciation of the monitored light source(s).
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Citations
19 Claims
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1. A lighting assembly, comprising:
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a diffusible light source to illuminate an area by providing light output, wherein the provided light output is measured in lumens; a photo detector configured to measure lumen output of the diffusible light source and a golden sample light beam; a directed light source to provide the golden sample light beam, wherein the golden sample light beam is used to calibrate the photo detector; and a controller configured to determine a photo detector calibration factor based on a first lumen output measurement of the directed light source and a second lumen output measurement of the directed light source, the calibration factor indicative of photo detector degradation over a period of time between the first lumen output measurement and the second lumen output measurement. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of controlling a lighting assembly, comprising:
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outputting illumination via a diffusible light source; providing a golden sample light beam via a directed light source to a photo detector; determining a photo detector calibration factor based on a first lumen output measurement of the directed light source and a second lumen output measurement of the directed light source, the calibration factor being indicative of photo detector degradation over a period of time between the first lumen output measurement and the second lumen output measurement; and adjusting a drive current of the lighting assembly provided to the diffusible light source so as to compensate for degradation of the photo detector. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14)
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15. A lighting assembly, comprising:
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a diffusible light source configured to provide illumination of an area via color mixed light output measured in lumens; a photo detector configured to measure lumen output of each color of the diffusible light source and a golden sample light beam; a directed light source to provide the golden sample light beam to use in calibrating the photo detector; and a controller configured to determine a photo detector calibration factor based on a first lumen output measurement of the directed light source and a second lumen output measurement of the directed light source, the calibration factor indicative of photo detector degradation over a period of time between the first lumen output measurement and the second lumen output measurement. - View Dependent Claims (16, 17, 18, 19)
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Specification