Fully-addressable sensor array for acoustic imaging systems
First Claim
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1. A fingerprint imaging system comprising:
- a high voltage source;
a low-voltage sense circuit; and
an array of acoustic elements, each acoustic element comprising;
a piezoelectric transducer comprising;
a drive/sense lead; and
a ground lead coupled to a circuit ground;
a pair of row/column drive selection switches coupled in series and configured to couple the drive/sense lead of the piezoelectric transducer to the high-voltage source when the acoustic element is operated in a high-voltage drive mode; and
a pair row/column sense selection switches coupled in series and configured to;
couple the drive/sense lead of the piezoelectric transducer to the low-voltage sense circuit when the acoustic element is operated in a low-voltage sense mode; and
decouple the drive/sense lead of the piezoelectric transducer from the low-voltage sense circuit when the acoustic element is operated in the high-voltage drive mode.
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Abstract
An acoustic imaging system can contain a plurality of individual acoustic elements that each contain an acoustic transducer, drive circuitry, and low voltage sense and/or read circuitry. In many embodiments both the drive circuitry and the read circuitry can be independently addressable. For example, if the individual acoustic elements are arranged into rows and columns, each acoustic element can include row/column drive circuit enable switches and row/column read circuit enable switches.
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Citations
19 Claims
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1. A fingerprint imaging system comprising:
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a high voltage source; a low-voltage sense circuit; and an array of acoustic elements, each acoustic element comprising; a piezoelectric transducer comprising; a drive/sense lead; and a ground lead coupled to a circuit ground; a pair of row/column drive selection switches coupled in series and configured to couple the drive/sense lead of the piezoelectric transducer to the high-voltage source when the acoustic element is operated in a high-voltage drive mode; and a pair row/column sense selection switches coupled in series and configured to; couple the drive/sense lead of the piezoelectric transducer to the low-voltage sense circuit when the acoustic element is operated in a low-voltage sense mode; and decouple the drive/sense lead of the piezoelectric transducer from the low-voltage sense circuit when the acoustic element is operated in the high-voltage drive mode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of driving an acoustic element of a fingerprint imaging sensor comprising an addressable drive circuit, the method comprising:
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opening each of a row sense select switch and column sense select switch that are coupled in series to disconnect a drive lead of the acoustic element from a low-voltage sense circuit; closing each of a row drive select switch and column drive select switch in series to connect the drive lead the acoustic element to a high-voltage source through the addressable drive circuit; and driving the acoustic element with a high-voltage signal generated by the high-voltage source;
wherein;a ground lead of the acoustic element is coupled to a circuit ground. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A method of reading an acoustic element of a fingerprint imaging sensor comprising an addressable read circuit and an addressable drive circuit, the method comprising:
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opening each of a row sense select switch and column sense select switch that are coupled in series to disconnect a sense/drive lead of the acoustic element from a low-voltage sense circuit; closing each of a row drive select switch and column drive select switch that are coupled in series to connect the sense/drive lead of the acoustic element to a high-voltage source through the addressable drive circuit; opening each of the row drive select switch and column drive select switch to decouple the acoustic element from the high-voltage source; enabling each of the row sense select switch and column sense select switch to couple the acoustic element to the addressable read circuit; and obtaining an electrical signal from the acoustic element with the addressable read circuit;
wherein;a ground lead of the acoustic element is coupled to a circuit ground. - View Dependent Claims (17, 18, 19)
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Specification