Ambient light sensors with infrared compensation
First Claim
1. A method of adjusting display brightness for a display in an electronic device that has an ambient light sensor and control circuitry while the electronic device is operated in an environment in which the electronic device is exposed to ambient light, the method comprising:
- with a first silicon photosensor in the ambient light sensor, outputting a first sensor reading indicative of how much visible light and infrared light are contained in the ambient light;
with a second silicon photosensor in the ambient light sensor, outputting a second sensor reading indicative of how much infrared light is contained in the ambient light;
processing ambient light data from the ambient light sensor to identify a lighting type associated with the ambient light; and
with the control circuitry, processing the sensor reading using the identified lighting type to produce a visible light reading indicative of how much visible light is contained in the ambient light, wherein the visible light reading is produced by applying a compensation factor to only the first sensor reading, and wherein the compensation factor is selected using the first sensor reading and the second sensor reading.
1 Assignment
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Accused Products
Abstract
An electronic device may have a display with a brightness that is adjusted based on ambient light data from one or more ambient light sensors. An ambient light sensor may include at least one silicon-based photosensor. The silicon-based photosensor may generate a corresponding raw sensor reading. Processing circuitry associated with the ambient light sensor may analyze the raw sensor reading to determine the type of light source that is present by comparing measurements from at least two different photosensors, by determining the color temperature of the light source, and/or by determining the modulation frequency of the light source. A compensation factor may then be selected by referring to a lookup table. The processing circuitry may compute a compensated sensor reading based on the raw sensor reading and the selected compensation factor. The brightness of the display may be adjusted based on the compensated sensor reading computed in this way.
66 Citations
16 Claims
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1. A method of adjusting display brightness for a display in an electronic device that has an ambient light sensor and control circuitry while the electronic device is operated in an environment in which the electronic device is exposed to ambient light, the method comprising:
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with a first silicon photosensor in the ambient light sensor, outputting a first sensor reading indicative of how much visible light and infrared light are contained in the ambient light; with a second silicon photosensor in the ambient light sensor, outputting a second sensor reading indicative of how much infrared light is contained in the ambient light; processing ambient light data from the ambient light sensor to identify a lighting type associated with the ambient light; and with the control circuitry, processing the sensor reading using the identified lighting type to produce a visible light reading indicative of how much visible light is contained in the ambient light, wherein the visible light reading is produced by applying a compensation factor to only the first sensor reading, and wherein the compensation factor is selected using the first sensor reading and the second sensor reading. - View Dependent Claims (2, 3, 4, 5)
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6. An electronic device, comprising:
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a display having an adjustable brightness level; an ambient light sensor configured to receive ambient light, wherein the ambient light sensor comprises; a first photosensor that generates a first sensor output that represents an amount of visible light and infrared light in the ambient light; a second photosensor that generates a second sensor output that represents an amount of infrared light in the ambient light; and control circuitry configured to compute a compensated sensor output based on the first sensor output and a selected compensation factor by applying the selected compensation factor directly to the first sensor output, wherein the selected compensation factor is selected based on the first sensor output and the second sensor output, and wherein the compensated sensor output is used to control the brightness level of the display. - View Dependent Claims (7, 8, 9, 10, 11)
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12. A method of adjusting display brightness for a display in an electronic device that has an ambient light sensor and control circuitry while the electronic device is operated in an environment in which the electronic device is exposed to ambient light from at least a given one of a plurality of light sources each producing a different respective ratio of infrared light to visible light, wherein the ambient light sensor includes a first and second silicon photosensors, the method comprising:
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using the control circuitry to receive a raw sensor output from the ambient light sensor, wherein the raw sensor output includes a first sensor output generated from the first silicon photosensor and a second sensor output generated from the second silicon photosensor; characterizing the ambient light to determine which of the plurality of light sources produced the ambient light; computing a compensated sensor output based on the raw sensor output without performing a subtraction operation based on the first and second sensor outputs; and with the control circuitry, adjusting the display brightness based on the compensated sensor output. - View Dependent Claims (13, 14, 15, 16)
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Specification