Methods and devices for improved charge management for three-dimensional and color sensing

A system to determine at least one spectral characteristic of multi-spectral optical energy, the system including:

• a CMOS optical energy detector, subjectable to said multi-spectral ambient optical energy, having at least one gate and an associated charge collection source region from which an output detection signal is obtainable, wherein a spectral response of said detector varies as a function of voltage coupled to said gate;
• means for collecting from said detector at least two output detection signals generated responsive to detected said multi-spectral optical energy;
• and
• means for determining from said at least two output detection signals at least one spectral characteristic of said multi-spectral optical energy.

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, generated in response to signal provided by a clock generator, and that detects a fraction of said optical energy reflected by said target with at least one said semiconductor photodetector, said photodetector comprising:

• a semiconductor substrate having a surface upon which said incoming optical energy can impinge onto an optical energy sensitive region, said surface defining an x-direction and a y-direction;
• at least a first elongate-shaped polysilicon gate disposed on said surface parallel to said y-direction, said first gate coupleable to a periodic first bias clock signal, synchronously generated by said clock generator, that is periodically high during a first bias regime to detect charge beneath said first gate generated by at least a fraction of said incoming optical energy, and is periodically low otherwise;
• a first source region formed in said substrate adjacent a distal end of said first gate;
• at least a second elongate-shaped polysilicon gate disposed on said surface parallel to said first elongate-shaped gate and spaced-apart in said x-direction a distance substantially shorter than a length of either said gate, said second gate coupleable to a periodic second bias clock signal synchronously generated by said clock generator, said periodic second bias clock signal being periodically high during a second bias regime to detect charge beneath said second gate generated by at least a fraction of said incoming optical energy, and is low otherwise;
• a second source region formed in said substrate adjacent a distal end of said second gate;
• wherein a majority of optically generated charge generated in said photodetector during said first bias regime is directed to said first source region, and a majority of optically generated charge generated in said photodetector during said second bias regime is directed to said second source region.

A CMOS-implementable optical energy detector to detect multi-spectral incoming optical energy to determine therefrom at least one spectral characteristic of said multi-spectral optical energy, said detector comprising:

• a semiconductor substrate having a surface upon which incoming said multi-spectral optical energy can impinge onto an optical energy sensitive region;
• at least one gate formed on said substrate having an associated charge collection source region from which an output detection signal is obtainable responsive to said incoming multi-spectral optical energy;
• means for coupling voltage to said at least one gate;
• wherein a spectral response of said detector varies dynamically as a function of said voltage coupled to said gate;
• wherein collection of at least two output detection signals generated by said detector responsive to detected said multi-spectral optical energy enables determination of at least one spectral characteristic of said multi-spectral optical energy.