System and circuit including multiple photo detectors and at least one optical barrier
First Claim
1. A system comprising:
- a plurality of photo detectors, each of the plurality of photo detectors configured to generate signals proportional to incident light;
an optical barrier configured to partially obstruct reflected light from reaching the plurality of photo detectors to produce a spatially dependent reflectance pattern that is dependent on a position of an object relative to a substrate; and
a control circuit configured to determine a position of the object during a reflectance measurement cycle using each of the plurality of photo detectors, the control circuit to;
calibrate each of the plurality of photo detectors to ambient light conditions;
measure ambient plus reflected light using each of the plurality of photo detectors;
correct the ambient plus reflected light based on the ambient light conditions to determine the reflected light received by each of the plurality of photo detectors; and
detect the position of the object based on a ratio of the reflected light received by at least two of the plurality of photo detectors.
1 Assignment
0 Petitions
Accused Products
Abstract
A system includes a plurality of photo detectors, which generate signals proportional to incident light. The system further includes an optical barrier adjacent to a surface and includes a control circuit. The optical barrier partially obstructs reflected light from reaching the plurality of photo detectors to produce a spatially dependent reflectance pattern that is dependent on a position of an object relative to a substrate. The control circuit determines a position of the object during a reflectance measurement cycle using each of the plurality of photo detectors by calibrating to ambient light conditions, measuring ambient plus reflected light, determining the reflected light and detecting the position of the object based on a ratio of the reflected light received by at least two of the plurality of photo detectors.
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Citations
22 Claims
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1. A system comprising:
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a plurality of photo detectors, each of the plurality of photo detectors configured to generate signals proportional to incident light; an optical barrier configured to partially obstruct reflected light from reaching the plurality of photo detectors to produce a spatially dependent reflectance pattern that is dependent on a position of an object relative to a substrate; and a control circuit configured to determine a position of the object during a reflectance measurement cycle using each of the plurality of photo detectors, the control circuit to; calibrate each of the plurality of photo detectors to ambient light conditions; measure ambient plus reflected light using each of the plurality of photo detectors; correct the ambient plus reflected light based on the ambient light conditions to determine the reflected light received by each of the plurality of photo detectors; and detect the position of the object based on a ratio of the reflected light received by at least two of the plurality of photo detectors. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A circuit comprising:
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a plurality of photo detectors, the plurality of photo detectors configured to generate electrical signals based on received light including at least one of ambient light and light variations caused by an object moving proximate to a substrate; an optical barrier configured to optically isolate at least one photo detector of the plurality of photo detectors from another photo detector of the plurality of photo detectors, the optical barrier adapted to produce a non-uniform reflectance pattern over the plurality of photo detectors from the light variations caused by the object; and a control circuit coupled to the plurality of photo detectors to receive the electrical signals, determine the light variations from the electrical signals, and determine a change in position of the object based on variation ratios of the light variations received by pairs of photo detectors of the plurality of photo detectors in response to determining the light variations. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A system comprising:
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a substrate including an active surface; a light-emitting diode configured to emit light above the active surface; a plurality of photo detectors disposed in the substrate adjacent to the active surface, an optical barrier adjacent to the active surface and configured to produce a spatially dependent reflectance pattern over the plurality of photo detectors based on reflectance of light by an object, the optical barrier configured to optically isolate at least one photo detector from at least one other photo detector of the plurality of photo detectors; and a control circuit configured to control activation of the light-emitting diode and to sequentially sample incident light with the light-emitting diode deactivated and a reflectance with the light-emitting diode activated using each photo detector of the plurality of photo detectors, the control circuit to determine position of an object relative to the substrate based on ratios of reflectances between adjacent photo detectors of the plurality of photo detectors. - View Dependent Claims (20, 21, 22)
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Specification