Optical reader with condensed CMOS circuitry
First Claim
1. Apparatus for reading encoded symbols, comprising:
- an integrated chip fabricated using a CMOS process, said integrated chip comprising an imaging array including a plurality of photosensitive cells;
a clock generator connected to said imaging array;
a common output bus connected to said imaging array;
an address generator connected to said imaging array, whereby said photosensitive cells are accessed according to a pattern;
an amplifier connected to said common output bus, said amplifier outputting an imaging signal comprising a sequence of pixel output values corresponding to an amount of light collected at each photosensitive cell of the imaging array; and
an edge detector connected to said amplifier, said edge detector comprising circuitry for detecting transitions between relatively higher and relatively lower amplitudes in said imaging signal corresponding to darker and lighter portions of a symbol being read; and
a symbology decoder coupled to said edge detector.
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Accused Products
Abstract
An optical or symbol reader including CMOS circuitry preferably integrated on a single chip. A CMOS optical reader chip comprises a CMOS imaging array having a plurality of pixels each with a dedicated pixel-site circuit. Charge is accumulated at each pixel location transferred upon demand to a common bus. In a preferred embodiment, exposure time of the imaging array is controlled using a feedback loop. One or more exposure control pixels are positioned adjacent to or within the imaging array and receive light along with the imaging array. The charge of the exposure control pixel or pixels is measured against a threshold level, and the amount of time taken to reach the threshold level determines the time exposure of the pixels of the imaging array. CMOS signal processing circuitry is employed which, in combination with the exposure control circuitry, minimizes time-to-read over a large range of light levels, while performing spatially optimal filtering. Clocking cycles and control signals are time-adjusted in accordance with the varying output frequency of the imaging array so as to provide invariant frequency response by the signal processing circuitry. A multi-dimensional CMOS imaging array is also provided having simultaneous pixel exposure with non-destructive readout of the pixel contents.
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Citations
20 Claims
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1. Apparatus for reading encoded symbols, comprising:
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an integrated chip fabricated using a CMOS process, said integrated chip comprising an imaging array including a plurality of photosensitive cells;
a clock generator connected to said imaging array;
a common output bus connected to said imaging array;
an address generator connected to said imaging array, whereby said photosensitive cells are accessed according to a pattern;
an amplifier connected to said common output bus, said amplifier outputting an imaging signal comprising a sequence of pixel output values corresponding to an amount of light collected at each photosensitive cell of the imaging array; and
an edge detector connected to said amplifier, said edge detector comprising circuitry for detecting transitions between relatively higher and relatively lower amplitudes in said imaging signal corresponding to darker and lighter portions of a symbol being read; and
a symbology decoder coupled to said edge detector. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for manufacturing an image reader, comprising the steps of:
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integrating, on a single integrated chip, an imaging array including a plurality of photosensitive cells, a clock generator, a common output bus, an address generator, an amplifier, and an edge detector, whereby said photosensitive cells are individually accessible in response to address generated by said address generator, and whereby said imaging array outputs an electrical signal to said common output bus for amplification by said amplifier;
connecting an output of said amplifier to an analog-to-digital (A/D) converter, said A/D converter outputting a digitized signal;
connecting said digitized signal to said edge detector; and
connecting said edge detector to a symbology decoder. - View Dependent Claims (12, 13)
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11. The method of claimed 10, further comprising the step of fabricating said integrated chip using a CMOS process.
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14. A single-chip bar code reader, comprising:
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an imaging array located on an integrated chip, said imaging array comprising a plurality of photosensitive cells;
a clock generator located on said integrated chip and connected to said imaging array;
a common output bus located on said integrated chip and connected to said imaging array;
an address generator located on said integrated chip and connected to said imaging array, said address generator outputting address signals whereby said photosensitive cells can be individually accessed;
an amplifier located on said integrated chip and connected to said output bus, said amplifier outputting a signal comprising a series of substantially discrete amplitudes corresponding to levels of accumulated charge at said plurality of photosensitive cells;
an analog-to-digital (A/D) converter located on said integrated chip and connected to said signal, said A/D converter outputting a digitized signal;
an edge detector located on said integrated chip and coupled to said digitized signal; and
a symbology decoder coupled to said edge detector. - View Dependent Claims (15, 16, 17)
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18. Apparatus for reading encoded symbols, comprising:
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an integrated chip fabricated using a CMOS process, said integrated chip comprising an imaging array including a plurality of photosensitive cells;
a clock generator connected to said imaging array;
a common output bus connected to said imaging array;
p2 an address generator connected to said imaging array, whereby said photosensitive cells are accessed according to a pattern;
an amplifier connected to said common output bus, said amplifier outputting an imaging signal comprising a sequence of pixel output values corresponding to an amount of light collected at each photosensitive cell of the imaging array; and
a symbology decoder coupled to said amplifier.
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19. A method for manufacturing an image reader, comprising the steps of:
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integrating, on a single integrated chip, an imaging array including a plurality of photosensitive cells, a clock generator, a common output bus, an address generator, an amplifier, and a symbology decoder, whereby said photosensitive cells are individually accessible in response to addresses generated by said address generator, and whereby said imaging array outputs an electrical signal to said common output bus for amplification by said amplifier;
connecting an output of said amplifier to an analog-to-digital (A/D) converter, said A/D converter outputting a digitized signal; and
connecting said digitized signal to said symbology decoder.
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20. A single-chip bar code reader, comprising:
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an imaging array located on an integrated chip, said imaging array comprising a plurality of photosensitive cells;
a clock generator located on said integrated chip and connected to said imaging array;
a common output bus located on said integrated chip and connected to said imaging array;
an address generator located on said integrated chip and connected to said imaging array, said address generator outputting address signals whereby said photosensitive cells can be individually accessed;
an amplifier located on said integrated chip and connected to said output bus, said amplifier outputting a signal comprising a series of substantially discrete amplitudes corresponding to levels of accumulated charge at said plurality of photosensitive cells;
an analog-to-digital (A/D) converter connected said signal, said A/D converter outputting a digitized signal; and
a symbology decoder located on said integrated chip, said symbology decoder connected to said digitized signal.
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Specification