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US 6,249,618 B1Granted
Circuit architecture and method for switching sensor resolution
AssigneeSyscan, Inc.
InventorAlpha Hou
Life of this patent
Estimating the term…
Abstract
The disclosed architecture for an image sensor and the associated method employ an internal switching mechanism controlled by a much reduced number of shift registers to facilitate the readout of electronic signals generated by the photodetectors in the image sensor. The switching mechanism comprises resolution switches that can act sequentially or simultaneously so that image resolution can be controlled within the image sensor. Further, the overall performance of the image sensor is improved.
Claims19
An improved image sensor comprising:
- an array of photodetectors and storage capacitors, each of the photodetectors, connected to one of the storage capacitors through a dumping switch, responsive to light impinged thereupon and independently producing an electronic signal after the photodetectors are collectively reset by a reset signal, wherein the electronic signal from each of the photodetectors is transferred to the storage capacitor thereof when the dumping switch is closed;
- a multiplexer comprising a plurality of groups of switches, each of the switches coupled to one of the storage capacitors;
- the groups of switches being serially turned on in synchrony with a clock control signal;
- wherein when one of the groups of switches are turned on, respective electronic signals from the storage capacitors coupled by the one of the groups of switches are respectively read out;
- and
- a number of resolution switches, each operating in synchrony with the clock control signal and receiving the respective electronic signals.
3 more elements
An improved image sensor comprising:
- an array of N photodetectors, N storage capacitors and N dumping switches, each of the N photodetectors, connected to one of the N storage capacitors through one of the N dumping switches, responsive to light impinged thereupon and independently producing an electronic signal after the photodetectors are collectively reset by a reset signal, wherein the electronic signal from each of the N photodetectors is stored onto one of the N storage capacitors when a corresponding one of the N dumping switches is closed;
- a multiplexer comprising an array of N switches, each of the switches coupled to one of the N storage capacitors, the N switches grouped into M groups, each of the M groups including K switches;
- wherein K=N/M;
- an array of M data registers, each of the M data registers being coupled to one group of the switches in the M groups;
- and
- K resolution switches, each of the K resolution switches coupled to one of the K switches in each of M groups;
- and
- wherein one group of the switches are turned on simultaneously by one of the M data registers to cause the electronic signal in each of the N storage capacitors coupled by the one of the switches to read out to one of the K resolution switches.
5 more elements
A method for controlling image resolution with an image sensor, the method comprising:
- generating N electronic signals respectively from N photodetectors in the image sensor when the N photodetectors are exposed to an object;
- shifting the N electronic signals respectively to N temporary memory cells after an exposure control signal stops;
- turning on an array of N switches in a predefined manner, each of the N switches coupled to one of the N temporary memory cells;
- wherein the N switches are grouped into M groups, each of the M groups includes K switches and wherein K=N/M;
- and
- outputting the N electronic signals respectively from the N temporary memory cells to K resolution switches that are coupled to an amplifier subsequently producing an output signal.
3 more elements
Dependencies are inferred from the claim text.