Integrating chamber LED lighting with pulse amplitude modulation to set color and/or intensity of output
First Claim
1. A lighting method, for emitting visible light of a set color characteristic so as to be humanly perceptible, the lighting method comprising:
- driving a first source of light with a first signal comprising a first sequence of pulses, to produce light of a first color;
modulating amplitude of the first sequence of pulses, to control the first source of light, so as to output a modulated amount of the light of the first color;
driving a second source of light with a second signal comprising a second sequence of pulses, to produce light of a second color, wherein the second color is different from the first color;
modulating amplitude of the second sequence of pulses, to control the second source of light, so as to output a modulated amount of the light of the second color;
diffusely reflecting light of the first and second colors from the first and second sources within an optical cavity, so as to optically combine light of the first and second colors to form humanly visible combined light;
sensing a color characteristic of the combined light;
controlling at least one of the amplitude modulations in response to the sensed color characteristic of the combined light in such a manner as to maintain the color of the combined light at least substantially in accordance with a light color setting; and
emitting the controlled combined light from the optical cavity so that it may be perceived by a person.
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Accused Products
Abstract
An exemplary system to provide visible lighting of a selectable spectral characteristic (e.g. a selectable color combination of light) uses an optical integrating cavity or other diffuse mixing element to combine light of different colors from different color LEDs. Amplitude modulation of pulsed operation the light sources, e.g. pulse amplitude modulation added to a baseline forward bias current for each of the LEDs, controls the amount of each light color supplied to the diffuse mixing element and thus the amount included in the combined light output of the system. A color sensor may provide feedback as to a color characteristic of the combined light, for closed-loop control of one or more of the pulse amplitude modulations. Examples are also disclosed that utilize phosphor doping of one or more of the system'"'"'s reflective elements, to add desired wavelengths of light to the combined output.
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Citations
37 Claims
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1. A lighting method, for emitting visible light of a set color characteristic so as to be humanly perceptible, the lighting method comprising:
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driving a first source of light with a first signal comprising a first sequence of pulses, to produce light of a first color;
modulating amplitude of the first sequence of pulses, to control the first source of light, so as to output a modulated amount of the light of the first color;
driving a second source of light with a second signal comprising a second sequence of pulses, to produce light of a second color, wherein the second color is different from the first color;
modulating amplitude of the second sequence of pulses, to control the second source of light, so as to output a modulated amount of the light of the second color;
diffusely reflecting light of the first and second colors from the first and second sources within an optical cavity, so as to optically combine light of the first and second colors to form humanly visible combined light;
sensing a color characteristic of the combined light;
controlling at least one of the amplitude modulations in response to the sensed color characteristic of the combined light in such a manner as to maintain the color of the combined light at least substantially in accordance with a light color setting; and
emitting the controlled combined light from the optical cavity so that it may be perceived by a person. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A lighting system, for emitting visible light of a set color characteristic so as to be humanly perceptible, comprising:
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a first source of light, for producing light of a first color, in an amount responsive to a first drive signal;
a second source of light, for producing light of a second color, in an amount responsive to a second drive signal;
control circuitry for generating the first drive signal so as to comprise a first amplitude modulated pulse sequence and for generating the second drive signal so as to comprise a second amplitude modulated pulse sequence, to control the first source to output a modulated amount of light of the first color and to control the second source to output a modulated amount of light of the second color in accord with a light color setting;
an optical integrating cavity having a diffusely reflective interior surface and coupled to receive light of the first and second colors from the first and second sources, for optically combining the light of the first and second colors to form humanly visible combined light;
a transmission path for allowing emission of the combined light from the optical cavity so that it may be perceived by a person; and
a color sensor for sensing a color characteristic of the combined light and supplying an indication of the sensed color characteristic to the control circuitry, wherein the control circuitry controls the modulation of the amplitude of pulses of at least one of the first and second drive signals in response to the indication of the sensed color characteristic from the color sensor so that the combined light has a color characteristic at least substantially corresponding to the light color setting. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. A lighting method, comprising:
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generating a first drive signal comprising a first baseline current and a first sequence of pulses added to the first baseline current;
driving a first light emitting diode to produce light of a first color with the first drive signal, the first baseline current being sufficient to forward bias the first light emitting diode;
modulating amplitude of the first sequence of pulses, to control the first light emitting diode so as to produce a modulated amount of the light of the first color;
generating a second drive signal comprising a second baseline current and a second sequence of pulses added to the second baseline current;
driving a second light emitting diode to produce light of a second color with the second drive signal, the second baseline current being sufficient to forward bias the second light emitting diode;
modulating amplitude of the second sequence of pulses, to control the second light emitting diode so as to output a modulated amount of the light of the second color; and
diffusely mixing the light of the first and second colors so as to optically combine light of the first and second colors to form humanly visible combined light of a color characteristic set at least in part by the modulating of the amplitude of the first and second sequences of pulses. - View Dependent Claims (27, 28, 29, 30, 31, 37)
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32. A lighting system, comprising:
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a first light emitting diode, for producing light of a first color;
a second light emitting diode, for producing light of a second color different from the first color;
first drive circuitry for producing a first drive signal for driving the first light emitting diode, the first drive signal comprising a first baseline current for forward biasing the first light emitting diode and a first sequence of pulses added to the first baseline current;
second drive circuitry for producing a second drive signal for driving the second light emitting diode, the second drive signal comprising a second baseline current for forward biasing the second light emitting diode and a second sequence of pulses added to the first baseline current;
control circuitry for controlling the drive circuits to control amplitude the first and second sequences of pulses; and
an optical diffusing element, for diffusely processing the light of the first and second colors in such a manner as to combine processed light of the first color with processed light of the second color to form combined light. - View Dependent Claims (33, 34, 35, 36)
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Specification