Methods and devices for charge management for three-dimensional sensing
First Claim
1. For use in a system that illuminates a target with optical energy having a modulated periodic waveform that includes a high frequency component and that detects with at least one photodetector a fraction of said optical energy reflected by said target, a method of improving detection comprising the following steps:
- providing each said photodetector with means for steering charge generated within said photodetector by said fraction of optical energy to a collection node in said photodetector; and
collecting at least some of said charge from said collection node.
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Abstract
Structures and methods for three-dimensional image sensing using high frequency modulation includes CMOS-implementable sensor structures using differential charge transfer, including such sensors enabling rapid horizontal and slower vertical dimension local charge collection. Wavelength response of such sensors can be altered dynamically by varying gate potentials. Methods for producing such sensor structures on conventional CMOS fabrication facilities include use of “rich” instructions to command the fabrication process to optimize image sensor rather than digital or analog ICs. One detector structure has closely spaced-apart, elongated finger-like structures that rapidly collect charge in the spaced-apart direction and then move collected charge less rapidly in the elongated direction. Detector response is substantially independent of the collection rate in the elongated direction.
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Citations
30 Claims
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1. For use in a system that illuminates a target with optical energy having a modulated periodic waveform that includes a high frequency component and that detects with at least one photodetector a fraction of said optical energy reflected by said target, a method of improving detection comprising the following steps:
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providing each said photodetector with means for steering charge generated within said photodetector by said fraction of optical energy to a collection node in said photodetector; and
collecting at least some of said charge from said collection node. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A CMOS-implementable semiconductor photodetector useable in a system that illuminates a target with optical energy having a modulated periodic waveform that includes a high frequency component, and detects a fraction of said optical energy reflected by said target with at least one said semiconductor photodetector, said semiconductor photodetector including:
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a substrate;
first and second sources formed in said substrate;
first and second charge transfer gates formed on a surface of said substrate;
a depletion gate disposed between said first and second charge transfer gates;
wherein charge generated within said substrate by optical energy is steered to at least one of said first and second sources responsive to voltage signals coupleable to said first and second charge transfer gates. - View Dependent Claims (10, 11, 12, 13, 14)
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15. For use in a system that illuminates a target with optical energy having a modified periodic waveform that includes a high frequency component and that detects with at least one semiconductor photodetector a fraction of said optical energy reflected by said target, a method of improving detection performance comprising the following steps:
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providing each said semiconductor photodetector with a first group and a second group of spaced-apart elongated structures formed on a substrate, wherein a distance in an x-direction separating adjacent said structures is substantially less than a length in a y-direction of said structures;
dynamically biasing said semiconductor photodetector such that detection-generated charge within said substrate is moved at a first rate in said x-direction for local collection by at least at a first region of said elongated structures, and at least some of said detection-generated charge at said first region is moved at a second rate in said y-direction for collection at a second region of said elongated structures;
wherein performance of said semiconductor photodetector is substantially dependent on said first rate and is substantially independent of said second rate. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22)
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23. For use in a system that illuminates a target with optical energy having a modulated periodic waveform that includes a high frequency component and that detects a fraction of said optical energy reflected by said target, at least one CMOS-implementable semiconductor photodetector used with said system to detect said fraction, said semiconductor photodetector including:
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a first group and a second group of spaced-apart elongated structures formed on a substrate, wherein distance in an x-direction separating adjacent said structures is substantially less than a length in a y-direction of said structures;
said semiconductor photodetector being biasable such that detection-generated charge within said substrate is moved at a first rate in said for local collection by at least at a first region of said elongated structures, and at least some of said detection-generated charge at said first region is moved at second rate in said y-direction for collection at a second region of said elongated structures;
wherein performance of said semiconductor photodetector is substantially dependent on said first rate and is substantially independent of said second rate. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30)
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Specification