LED illumination system having an intensity monitoring system
First Claim
1. A light source comprising a first component light source, said first component light source comprising:
- N LEDs, each LED having a light emitting chip in a package, said light emitting chip emitting light in a forward direction through a top surface of said light emitting chip and light in a side direction through a side surface of said light emitting chip, wherein N>
1, said light generated in said forward direction being determined by a drive signal coupled to that LED, a portion of said light in said side direction leaving said package;
a photo-detector; and
a collector positioned to direct primarily a portion of said light in said side direction that leaves said package of each of said LEDs onto said photo-detector, said photo-detector generating N intensity signals, each intensity signal having an amplitude related to the intensity of said light emitted in said side direction by a corresponding one of said LEDs and being independent of the intensity of light emitted by any other LED in said light source.
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Accused Products
Abstract
A light source and method for controlling the same. The light source includes a first component light source that includes N LEDs, a photo-detector, and a collector, where N>1. Each LED has a light emitting chip in a package. The light emitting chip emits light in a forward direction and light in a side direction. The light generated in the forward direction is determined by a drive signal coupled to that LED. A portion of the light in the side direction leaves the package. The collector is positioned such that a portion of the light in the side direction that leaves the package of each of the LEDs is directed onto the photo-detector. The photo-detector generates N intensity signals, each intensity signal having an amplitude related to the intensity of the light emitted in the side direction by a corresponding one of the LEDs.
73 Citations
15 Claims
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1. A light source comprising a first component light source, said first component light source comprising:
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N LEDs, each LED having a light emitting chip in a package, said light emitting chip emitting light in a forward direction through a top surface of said light emitting chip and light in a side direction through a side surface of said light emitting chip, wherein N>
1, said light generated in said forward direction being determined by a drive signal coupled to that LED, a portion of said light in said side direction leaving said package;a photo-detector; and a collector positioned to direct primarily a portion of said light in said side direction that leaves said package of each of said LEDs onto said photo-detector, said photo-detector generating N intensity signals, each intensity signal having an amplitude related to the intensity of said light emitted in said side direction by a corresponding one of said LEDs and being independent of the intensity of light emitted by any other LED in said light source. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 15)
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10. A light source comprising a first component light source, said first component light source comprising:
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N LEDs, each LED having a light emitting chip in a package, said light emitting chip emitting light in a forward direction and light in a side direction, wherein N>
1, said light generated in said forward direction being determined by a drive signal coupled to that LED, a portion of said light in said side direction leaving said package;a photo-detector; and a collector positioned to direct a portion of said light in said side direction that leaves said package of each of said LEDs onto said photo-detector, said photo-detector generating N intensity signals, each intensity signal having an amplitude related to the intensity of said light emitted in said side direction by a corresponding one of said LEDs, wherein said first component light source comprises a bus and a first interface circuit for controlling N signals, each signal determining a light intensity to be generated in said forward direction by a corresponding one of said LEDs, said interface circuit further coupling said N intensity signals to said bus in response to a control signal identifying said first interface, said light source further comprising a second component light source, said second component light source comprising; N LEDs, each LED having a light emitting chip in a package, said light emitting chip emitting light in a forward direction and light in a side direction, wherein N>
1, said light generated in said forward direction being determined by a drive signal coupled to that LED, a portion of said light in said side direction leaving said package;a photo-detector; a collector positioned to direct a portion of said light in said side direction that leaves said package of each of said LEDs onto said photo-detector, said photo-detector generating N intensity signals, each intensity signal having an amplitude related to the intensity of said light emitted in said side direction by a corresponding one of said LEDs and a second interface circuit for controlling N signals, each signal determining a light intensity to be generated in said forward direction by a corresponding one of said LEDs in said second component light source, said interface circuit further coupling said N intensity signals to said bus in response to a control signal identifying said second interface. - View Dependent Claims (11)
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12. A method for illuminating a device with light from a plurality of LEDs, each LED having a light emitting chip in a package, said light emitting chip emitting light in a forward direction through a top surface of said light emitting chip and light in a side direction through a side surface of said light emitting chip, said light generated in said forward direction being determined by a drive signal coupled to that LED, a portion of said light in said side direction leaving said package, said method comprising:
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collecting primarily a portion of said light in said side direction from each of said LEDs; measuring the intensity of said collected light for each of said LEDs to generate a measured intensity value for each of said LEDs that measured intensity value being independent of said measured intensity values of each of said other LEDs; controlling said drive signals of said LEDs to maintain each of said measured intensity values at a target value. - View Dependent Claims (13, 14)
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Specification