Solid state light with controlled light output
First Claim
Patent Images
1. A solid state light, comprising:
- a solid state light source driven by a drive signal and producing a light beam;
optics transmitting the light beam; and
a feedback circuit monitoring a produced light beam portion reflected from said optics, said feedback circuit responsively adjusting said produced light beam as a function of said monitored light beam portion to maintain said produced light beam at a fixed predetermined output, further comprising an ambient light detector, wherein said feedback circuit establishes said fixed predetermined output as a function of said ambient light.
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Abstract
A solid state light apparatus ideally suited for use in traffic control signals provided with optical feedback to achieve a constant light output, preferably by detecting back-scattered light from a diffuser centered above an LED array. The control logic allows for the LEDs to be individually driven, and having their drive characteristics changed over time to ensure a uniform beam of light is generated at an intensity meeting DOT standards, across the life of the device. The optical feedback also establishes the uniform beam intensity level as a function of sensed ambient light to discern day and night operation.
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Citations
27 Claims
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1. A solid state light, comprising:
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a solid state light source driven by a drive signal and producing a light beam;
optics transmitting the light beam; and
a feedback circuit monitoring a produced light beam portion reflected from said optics, said feedback circuit responsively adjusting said produced light beam as a function of said monitored light beam portion to maintain said produced light beam at a fixed predetermined output, further comprising an ambient light detector, wherein said feedback circuit establishes said fixed predetermined output as a function of said ambient light. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of operating a solid state light having optics transmitting a light beam, comprising the steps of:
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driving the solid state light with a drive signal to generate the light beam; and
monitoring a parameter of said solid state beam reflected from the optics and responsively adjusting said drive signal to maintain said light beam at a predetermined intensity level as a function of said monitored parameter, further comprising the step of establishing said predetermined intensity level as a function of ambient light. - View Dependent Claims (14, 15, 16, 17)
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18. A solid state light, comprising:
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a solid state light source having a plurality of LEDs driven by a drive signal and collectively producing a single light beam; and
a feedback circuit comprising multiple photodiodes, each said photodiode monitoring a portion of said collectively produced single light beam, said feedback circuit responsively adjusting said collectively produced single light beam as a function of said monitored produced single light beam. - View Dependent Claims (19, 20)
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21. A solid state light, comprising:
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a solid state light source driven by a drive signal and producing a light beam;
optics transmitting the light beam; and
a feedback circuit monitoring a produced light beam portion reflected from said optics, said feedback circuit responsively adjusting said produced light beam as a function of said monitored light beam portion by adjusting said drive signal to maintain said produced light beam at a fixed predetermined output, said drive signal having a time varying component. - View Dependent Claims (22, 23)
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24. A solid state light, comprising:
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a solid state light source driven by a drive signal and producing a light beam;
a lens transmitting the light beam; and
a feedback circuit monitoring a produced light beam portion reflected from said lens, said feedback circuit responsively adjusting said produced light beam as a function of primarily said monitored reflected light beam portion. - View Dependent Claims (25)
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26. A method of operating a solid state light having a lens transmitting a light beam, comprising the steps of:
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driving the solid state light with a drive signal to generate the light beam; and
monitoring a light beam portion reflected from the lens and responsively adjusting said drive signal to maintain said light beam at a predetermined intensity level as a function of primarily said monitored reflected light beam portion. - View Dependent Claims (27)
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Specification