Illumination Devices and Related Systems and Methods
First Claim
1. A method for controlling light intensity produced by an emission LED, comprising:
- measuring light from the emission LED with a photodetector using a signal induced on the photodetector by the emission LED;
measuring a temperature of the photodetector by forcing different currents through the photodetector and measuring a difference between voltages developed across the photodetector; and
adjusting light produced by the emission LED based on the signal induced on the photodetector by the emission LED and the temperature of the photodetector.
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Accused Products
Abstract
Illumination devices and related systems and methods are disclosed that can be used for LCD (Liquid Crystal Display) backlights, LED lamps, or other applications. The illumination devices can include a photo detector, such as a photodiode or an LED or other light detecting device, and one or more LEDs of different colors. A related method can be implemented using these illumination devices to maintain precise color produced by the blended emissions from such LEDs. One application for the illumination devices is backlighting for FSC (Field Sequential Color) LCDs (Liquid Crystal Displays). FSC LCDs temporally mix the colors in an image by sequentially loading the red, green, and blue pixel data of an image in the panel and flashing the different colors of an RGB backlight. Precise and uniform color temperature across such a display can be advantageously maintained by continually monitoring ratios of photodiode currents induced by the different colored LEDs in each illumination device as each color is flashed.
8 Citations
16 Claims
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1. A method for controlling light intensity produced by an emission LED, comprising:
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measuring light from the emission LED with a photodetector using a signal induced on the photodetector by the emission LED; measuring a temperature of the photodetector by forcing different currents through the photodetector and measuring a difference between voltages developed across the photodetector; and adjusting light produced by the emission LED based on the signal induced on the photodetector by the emission LED and the temperature of the photodetector. - View Dependent Claims (2, 3, 4, 5)
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6. A system for controlling the light intensity produced by an LED, comprising:
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an LED configured to produce light; a photodetector configured to receive light from the LED; and control circuitry configured to utilize the photodetector to determine a measurement for a signal induced on the photodetector by the light from the LED, to determine a temperature measurement by forcing different currents through the photodetector and measuring a difference between voltages developed across the photodetector, and to adjust the light produced by the LED based on the a signal induced on the photodetector by the light from the LED and the temperature of the photodetector. - View Dependent Claims (7, 8, 9, 10)
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11. A method for controlling light intensity produced by an LED, comprising:
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measuring light from an LED with a photodetector using a signal induced on the photodetector by the LED; measuring a temperature by forcing a single current through two photodetectors having different sizes and measuring a difference between voltages developed across the two photodetectors; and adjusting light produced by the LED based on the signal induced on the photodetector by the LED and the measured temperature.
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12. A system for controlling the light intensity produced by an LED, comprising:
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an LED configured to produce light; a first photodetector configured to receive light from the LED; a second and third photodetector configured to provide a temperature measurement; and control circuitry configured to utilize the first photodetector to determine a measurement for a signal induced on the first photodetector by the light from the LED, to determine the temperature measurement using the second and third photodetectors, and to adjust the light produced by the LED based on the signal induced on the first photodetector by the light from the LED and the temperature measurement. - View Dependent Claims (13, 14, 15, 16)
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Specification