CALIBRATED IMAGE-SENSOR-BASED AMBIENT LIGHT SENSOR
First Claim
1. Image-sensor-based ambient light sensing circuitry, comprising:
- an image sensor array;
an optically-black reference sensor array; and
control circuitry that produces an ambient light sensor reading based on data from the image sensor array and the reference sensor array.
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Accused Products
Abstract
An electronic device may be provided with an image sensor for capturing digital images. The image sensor may be used as part of image-sensor-based ambient light sensing circuitry for producing ambient light sensor readings. The image-sensor-based ambient light sensing circuitry may include a reference array. The reference array may be formed from an array of light sensor elements that are matched to elements in the image sensor but that are covered with a light blocking material. Control circuitry can measure current flow into the reference array and the image sensor array and can use current measurements from these arrays in producing a calibrated ambient light sensor reading. The control circuitry may make current measurements by measuring a decay time associated with the voltage of a discharging capacitor. A comparator, pulse generator, and switch may be used in periodically recharging the capacitor. The capacitor may be adjusted to ensure accurate readings.
69 Citations
27 Claims
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1. Image-sensor-based ambient light sensing circuitry, comprising:
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an image sensor array; an optically-black reference sensor array; and control circuitry that produces an ambient light sensor reading based on data from the image sensor array and the reference sensor array. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method of calibrating image-sensor-based ambient light sensor circuitry, comprising:
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measuring an image sensor current for an image sensor that is exposed to ambient light at an ambient light level; measuring a reference current for a reference array of light sensor elements that are covered with light blocking material; and producing an ambient light reading representative of the ambient light level based at least partly on the measured image sensor current and the measured reference current. - View Dependent Claims (16, 17, 18, 19, 20)
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21. An electronic device, comprising:
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image-sensor-based ambient light sensor circuitry configured to gather an ambient light reading for the electronic device; and a sensor that produces sensor data; and a display having a brightness level; and control circuitry configured to adjust the brightness level based on the ambient light reading and the sensor data. - View Dependent Claims (22, 23, 24, 25, 26, 27)
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Specification