System and method for color tuning light output from an LED-based lamp
First Claim
1. A method of performing a search in a one-dimensional search space within chromaticity space quantifying illumination, the method comprising:
- providing a target illumination spectrum and an illumination search space;
configuring a predetermined distance threshold from the target illumination spectrum; and
narrowing the illumination search space to match the target illumination spectrum by;
selecting by a processor a plurality of points in the illumination search space, wherein the plurality of points correspond to operating levels of light emitting diodes (LEDs) in an LED-based lamp;
determining by the processor a preferred point from the plurality of selected points, wherein the preferred point corresponds to a light generated by the LED-based lamp that has a lamp spectrum closest to the target illumination spectrum out of the plurality of points;
discarding by the processor a portion of the illumination search space that does not include the preferred point, wherein the discarded portion of the illumination search space is at least a buffer zone away from the preferred point; and
iterating by the processor the narrowing of the illumination search space in a remaining narrowed search space until one of the selected points provides a final lamp spectrum within the predetermined distance threshold of the target illumination spectrum.
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Accused Products
Abstract
Systems and methods for using an LED-based lamp for reproducing a target light are disclosed. A color-space searching technique is introduced here that enables the LED-based lamp to be tuned to generate light at a specific CCT by adjusting the amount of light contributed by each of the LED strings in the lamp. The target light is decomposed into different wavelength bands, and light generated by the LED-based lamp is also decomposed into the same wavelength bands and compared. The color-searching techniques allow the LED-based lamp to closely emulate a black body radiator given the limitations of the physical specification of color string in the LED strings.
30 Citations
30 Claims
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1. A method of performing a search in a one-dimensional search space within chromaticity space quantifying illumination, the method comprising:
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providing a target illumination spectrum and an illumination search space; configuring a predetermined distance threshold from the target illumination spectrum; and narrowing the illumination search space to match the target illumination spectrum by; selecting by a processor a plurality of points in the illumination search space, wherein the plurality of points correspond to operating levels of light emitting diodes (LEDs) in an LED-based lamp; determining by the processor a preferred point from the plurality of selected points, wherein the preferred point corresponds to a light generated by the LED-based lamp that has a lamp spectrum closest to the target illumination spectrum out of the plurality of points; discarding by the processor a portion of the illumination search space that does not include the preferred point, wherein the discarded portion of the illumination search space is at least a buffer zone away from the preferred point; and iterating by the processor the narrowing of the illumination search space in a remaining narrowed search space until one of the selected points provides a final lamp spectrum within the predetermined distance threshold of the target illumination spectrum. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of generating with a light-emitting diode (LED)-based lamp a light that has a light spectrum that substantially matches a target spectrum, comprising:
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capturing a target light having the target spectrum; generating with a lamp an actual light spectrum that substantially matches the target spectrum; decomposing the target light to determine contributions to the target light that correspond to a plurality of wavelength bands; generating candidates of light with the lamp, wherein the candidates of light are on or near a curve in chromaticity space; capturing the candidates of light; decomposing the candidates of light to determine contributions to the candidates of light that correspond to the plurality of wavelength bands; and identifying a closest candidate of light, wherein the contributions to the plurality of wavelength bands of the closest candidate of light substantially matches the contributions to the plurality of wavelength bands of the target light. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A method of generating with a light-emitting diode (LED)-based lamp light having a light spectrum, wherein the light spectrum substantially matches a reference spectrum of a reference light, the method comprising:
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capturing the reference light with a plurality of sensors, wherein the plurality of sensors receive light through a plurality of bandpass filters, and further wherein sensor readings include a signal corresponding to a total intensity of light filtered by each type of bandpass filter; generating and capturing with the plurality of sensors a first lighting sample having a warmest color in an operating range of the lamp; generating and capturing with the plurality of sensors a second lighting sample having a coolest color in the operating range of the lamp; generating and capturing with the plurality of sensors one or more additional lighting samples in the operating range of the lamp between the warmest color and the coolest color; using an equation to quantitatively determine a preferred sample of the lighting samples that has a spectrum closest to the reference spectrum, wherein the equation is dependent upon the sensor readings for the reference light and the sensor readings for the lighting samples; when the closeness of the spectrum of the preferred sample is not within a threshold of the reference spectrum, discarding a portion of the operating range of the lamp that does not include the preferred sample, wherein the discarded portion of the operating range is at least a buffer zone away from the preferred sample; and iterating the above steps in a remaining operating range until a spectrum of one of the lighting samples is within the threshold of the reference spectrum. - View Dependent Claims (16, 17, 18, 19, 20)
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21. A system for generating light having a spectrum substantially similar to a reference spectrum of a reference light, the system comprising:
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a light-emitting diode (LED)-based lamp configured to generate candidates of light having different correlated color temperatures (CCT), wherein the candidates of light correspond to points in an operating range of the lamp; and a controller having a sensor, wherein the sensor is configured to capture light impinging on the sensor, wherein the controller is configured to search for a preferred candidate of light in the operating range of the LED-based lamp that produces a spectrum substantially similar to the reference spectrum based on the captured light. - View Dependent Claims (22, 23, 24)
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25. A method of calibrating an LED-based lamp having a plurality of LED strings, the method comprising:
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turning on the plurality of LED strings simultaneously and receiving sensor readings of generated light; turning off the plurality of LED strings and receiving sensor readings of ambient light; turning on each LED string individually and receiving sensor readings for each LED string; and calculating a ratio of measured output power to expected output power for each LED string, wherein the ratios are used as multiplicative factors with driving currents in a color model for the lamp that provides driving currents for each of the plurality of LED strings to produce light having a range of correlated color temperatures (CCT). - View Dependent Claims (26, 27, 28)
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29. A system for calibrating light-emitting diode (LED) strings in an LED-based lamp, the system comprising:
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the LED-based lamp configured to run the following lamp settings;
turn the plurality of LED strings on, turn the plurality of LED strings off, and turn on each LED string individually, and further configured to receive sensor readings for each of the lamp settings; anda sensor configured to capture light impinging on the sensor and provide sensor readings corresponding to received light intensity, wherein the lamp runs an algorithm to determine a ratio of measured power to expected power for each LED string, and wherein the ratios are used as multiplicative factors with driving currents in a color model for the lamp that provides driving currents for each of the plurality of LED strings to produce light having a range of correlated color temperatures (CCT). - View Dependent Claims (30)
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Specification