Patent EP0459808A2 successfully refreshed from Google Patents.
EP0459808A2
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Digitizers
Assignee: Personal Biometric Encoders Ltd
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Filing: 1991-05-30
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Granted: —
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Expires: 2011-05-30
Abstract
Abstract A digitizer of high resolution and capable of discerning a pattern of applied low differential pressure is described. The digitizer comprises a matrix of cells each having a switch means connecting contact pad (24) and contact pad (22b) including a resistive means, and means for determining the pattern of a plurality of simultaneously applied pressures. <IMAGE>
Inventors
- 👤 George White
- 👤 Nicholas John Parsons
- 👤 Paul Kevin Kimber
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 07:06
CPC Classifications
G; G06; G06F; G06F3/00; G06F3/01; G06F3/03; G06F3/041; G06F3/045; G06V; G06V40/00; G06V40/10; G06V40/12; G06V40/13; G06V40/1306
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
82 words
A digitizer comprising a matrix of pressure sensitive cells on an undeformable support, the matrix being defined by a plurality of parallel first conductors and a plurality of parallel second conductors overlying the first conductors, each cross-over point providing one of the cells, switch means associated with each cross-over point, resistive means in each of the switch means, and an overlying resiliently deformable film providing, for each cell, a contact bridge for operating the switch means in response to an applied pressure.
Claim 2
Dependent Claim
38 words
A digitizer as claimed in claim 1 wherein each resistive means comprises a thin film resistor connected by one end to an adjacent one of the first conductors and by a second end to a respective metal pad.
Claim 3
Dependent Claim
27 words
A digitizer as claimed in claim 2 including an insulative layer overlying the first conductors and the resistors, and having respective first vias for each metal pad.
Claim 4
Dependent Claim
46 words
A digitizer as claimed in claim 3 wherein the second conductors are supported upon the insulative layer and wherein first metal contact pads connected to the second conductors and second metal contact pads, each connected to a respective metal pad, are supported by the insulative layer.
Claim 5
Dependent Claim
21 words
A digitizer as claimed in claim 4 wherein the first metal contact pads and the second metal contact pads are interdigitated.
Claim 6
Dependent Claim
31 words
A digitizer as claimed in claim 4 or 5 wherein the contact bridges are of dimension greater than the first and second contact pad spacing but less than the intercell spacing.
Claim 7
Dependent Claim
47 words
A digitizer as claimed in claim 4, 5 or 6 including a further insulating layer covering the second conductors but having, for each cell, a respective second via in the form of a well at the bottom of which are exposed the contact pads of the cell.
Claim 8
Dependent Claim
53 words
A digitizer as claimed in claim 7 wherein the resiliently deformable film overlies the matrix with the bridge contacts thereof over the cell wells whereby deformation of the film, by the application of pressure causes one or more of the bridge contacts to electrically bridge the contact pads to operate the switch means.
Claim 9
Dependent Claim
26 words
A digitizer as claimed in any preceding claim wherein the resiliently deformable film is of MYLAR and has a thickness of the order of 3 µm.
Claim 10
Dependent Claim
18 words
A digitizer as claimed in any preceding claim wherein the matrix has a cell density of 10000 cells/cm².
Claim 11
Dependent Claim
16 words
A digitiser substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.
Claim 12
Dependent Claim
26 words
A fingerprint verifier comprising a digitizer as claimed in any preceding claim including means for comparing a detected pattern of applied pressure with a known pattern.
Claim 13
Dependent Claim
21 words
A verifier as claimed in claim 12 including a wall peripheral to the matrix to locate a fingertip on the matrix.
Claim 14
Independent Claim
20 words
A method of fabricating a digitizer as claimed in any of claims 1 to 11 and substantially as hereinbefore described.
References Cited (Backward Citations)
No citation records indexed.
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