Signature verification sensor
First Claim
1. A device for producing output signals indicative of the magnitude and location of application of an applied force, comprising:
- a first electrically conductive surface;
a second surface including a plurality of electrically conductive areas defined thereon;
said first electrically conductive surface being disposed in a spaced apart capacitive relationship with said second surface having said plurality of electrically conductive areas;
generating means for generating a corresponding plurality of electrical signals representative of the capacitance between said first electrically conductive surface and each of said plurlity of second electrically conductive areas;
application of said force causing deflection of said first electrically conductive surface producing a change in each of said corresponding plurality of electrical signals, the magnitude and ratio of said changes being associated with a unique location of application of said force on said first electrically conductive surface;
means for adjusting the magnitude of change of said corresponding plurality of electrical signals in response to a vertical force of unit magnitude located at a reference location on said first electrically conducting surface.
3 Assignments
0 Petitions
Accused Products
Abstract
A sensor having a particular application in the field of signature verification is disclosed. In the presently preferred embodiment, two plates are disposed in a spaced apart relationship and constructed to provide a plurality of electrical capacitors. Pressure applied at any point on one plate will cause deflection of that plate toward the other plate changing the capacitance of each capacitor. The change in capacitancegenerates electrical signals which may be combined and processed to provide signals indicative of the location on the plate at which the pressure was applied and indicative of the magnitude of its vertical component. In an alternate embodiment, first and second spaced apart parallel lines are disposed on one plate with a third ground line interlaced between the first and second lines. A voltage is applied across the first and second lines and the capacitance between the first and second lines is measured as a function of the distance between the plates. An additional alternate embodiment of the sensor utilizing a conductive fluid disposed between the plates is also disclosed.
87 Citations
8 Claims
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1. A device for producing output signals indicative of the magnitude and location of application of an applied force, comprising:
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a first electrically conductive surface; a second surface including a plurality of electrically conductive areas defined thereon; said first electrically conductive surface being disposed in a spaced apart capacitive relationship with said second surface having said plurality of electrically conductive areas; generating means for generating a corresponding plurality of electrical signals representative of the capacitance between said first electrically conductive surface and each of said plurlity of second electrically conductive areas; application of said force causing deflection of said first electrically conductive surface producing a change in each of said corresponding plurality of electrical signals, the magnitude and ratio of said changes being associated with a unique location of application of said force on said first electrically conductive surface; means for adjusting the magnitude of change of said corresponding plurality of electrical signals in response to a vertical force of unit magnitude located at a reference location on said first electrically conducting surface. - View Dependent Claims (2, 3, 4, 5)
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6. A device for producing output signals indicative of the magnitude and location of application of an applied force, comprising:
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a first electrically conductive surface; a second surface including a plurality of electrically isolated areas; said first electrically conductive surface being disposed in spaced apart relationship with said second surface; first and second conductive lines disposed within each of said isolated areas; generating means for generating a corresponding plurality of electrical signals representative of the capacitance between said first and second conductive lines within each isolated area as a function of the distance separating said first and second surfaces; a third conductive line disposed between said first and second conductive lines and coupled to a grounf potential; application of said force causing deflection of said first electrically conductive surface producing a change in each of said corresponding plurality of electrical signals, the magnitude and ratio of said changes being associated with a unique location of applicaiton of said force on said first electrically conductive surface. - View Dependent Claims (7, 8)
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Specification