Driver circuit for a contact imaging array
First Claim
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1. A capacitive fingerprint sensing device comprising:
- an array of sense elements spaced apart, each of the sense elements comprising a sensing electrode and an amplifier circuit wherein the amplifier circuit amplifies voltage induced in the sensing electrode by a biological source, each sense element lacking means for inducing, from within the sensing device, any charge on its respective sensing electrode.
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Abstract
A fingerprint sensing device and recognition system includes an array of closely spaced apart sensing elements each comprising a sensing electrode and an amplifier circuit. The device is used to sense electrical charge on a fingertip and obviates the need to pre-charge the sensing electrode. The device may be constructed with a single die or with multiple dies.
136 Citations
18 Claims
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1. A capacitive fingerprint sensing device comprising:
an array of sense elements spaced apart, each of the sense elements comprising a sensing electrode and an amplifier circuit wherein the amplifier circuit amplifies voltage induced in the sensing electrode by a biological source, each sense element lacking means for inducing, from within the sensing device, any charge on its respective sensing electrode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A capacitive fingerprint sensing device comprising:
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a substrate; an array of dies spaced in close proximity to each other for sensing a fingerprint, the array of dies being bonded to the substrate, each die comprising a ground plane, an array of sense elements spaced apart and disposed on and spaced from one face of the ground plane, each sense element comprising a sensing electrode and an amplifier circuit wherein the amplifier circuit amplifies voltage induced in the sensing electrode by a biological source, each die lacking means for inducing, from within the sensing device, any charge on each sense element in the array of sense elements.
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14. A capacitive fingerprint sensing device comprising:
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at least a die for sensing a fingerprint, each at least a die comprising an array of sense elements spaced apart some sense elements comprising a sensing electrode, electrostatic protection means, a low pass filter, and an amplifier circuit wherein the amplifier circuit is capable of amplifying a voltage induced in the sensing electrode by a biological source, a die lacking means for inducing, from within the sensing device, any charge on the sense elements in the array of sense elements. - View Dependent Claims (15, 16, 17, 18)
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Specification