Method and apparatus using liquid crystal light valve to filter incident light on a photodetector
First Claim
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1. Apparatus, comprising:
- a photodetector;
a light valve comprising a liquid crystal element, positioned to filter incident light on the photodetector; and
a control system to determine whether incident light on the photodetector is causing the photodetector to saturate and, if so, apply an electrical stimulus to adjust the light valve;
wherein the light valve comprises a plurality of stacked liquid crystal elements, each of which serves to filter a different range of light wavelengths, and each of which is separately controlled by the control system.
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Abstract
In one embodiment, light is detected using a photodetector. If the detected light is causing the photodetector to saturate, one or more liquid crystal light valves are adjusted to filter the amount of incident light on the photodetector.
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Citations
17 Claims
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1. Apparatus, comprising:
- a photodetector;
a light valve comprising a liquid crystal element, positioned to filter incident light on the photodetector; and
a control system to determine whether incident light on the photodetector is causing the photodetector to saturate and, if so, apply an electrical stimulus to adjust the light valve;
wherein the light valve comprises a plurality of stacked liquid crystal elements, each of which serves to filter a different range of light wavelengths, and each of which is separately controlled by the control system. - View Dependent Claims (2, 3, 4, 5, 6)
- a photodetector;
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7. Apparatus, comprising:
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at least one light emitting element; a photodetector, positioned to receive light emitted by at least some of the light emitting elements; a light valve comprising a liquid crystal element, positioned to filter incident light on the photodetector; and a control system to i) determine whether incident light on the photodetector is causing the photodetector to saturate and, if so, apply an electrical stimulus to adjust the light valve, and ii) in response to the light detected by the photodetector, regulate a drive signal of a first one or more of the light emitting elements, thereby regulating the light that is emitted by the first one or more light emitting elements. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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Specification