Document verifier using photovoltaic cell with light sensitive bars

Claim 2

A document verification system comprising a light source; a photovoltaic cell formed in approximately the same pattern as the document to be verified; and means for causing relative movement between the document, the cell and the light source, said document including a plurality of bars, said photovoltaic cell also including a plurality of similar bars of light-sensitive material of the same relative size and spacing as the bars of the documents, said bars being separated by non-light-sensitive material.

Claim 3

A document verification system as defined in claim 1 wherein said bars are parallel.

Claim 4

A document verification system as defined in claim 1 additionally comprising a fiber optics image conduit positioned between the light source and the cell and conducting an image of the document from the document to the cell.

Claim 5

A document verification system as defined in claim 2 wherein said cell includes a flat chip of silicon doped with P- and N-type impurities, said flat chip being doped with one of said types of impurities therethrough, said chip having a photosensitive surface thereon formed by the other of said types of impurities fused into the one type impurity chip, said chip being etched at selected portions of said surface to remove portions of said photosensitive surface providing said pattern of photosensitive material.

Claim 6

A document verification system as defined in claim 2 additionally comprising first means for receiving the output Of said cell and for converting those portions thereof which are above a given amplitude into pulses of constant voltage of varying time duration which is determined by the time that said portions are above said amplitude, second means for differentiating the output of said first means to produce for each input pulse an output pulse that is constant in amplitude and time duration, integrating means for counting the output pulses of said differentiating means and producing an output directly proportional to the number of second means output pulses, and switch means receiving the output of said integrating means and arranged to be turned on by an output of given amplitude from said integrating means.

Claim 7

A document verification system as defined in claim 5 wherein said means for causing relative movement comprises a spring and a pair of limit stops and a cart, said cell being mounted on said cart, said limit stops being spaced apart a fixed distance, one of said limit stops normally acting to hold said cart at a first position, said one stop being movable to permit said cart to move from said first position to a second position under the action of the spring, said first and second positions being a given distance apart so that the travel of said cart between said positions is always the same distance.

Claim 8

A document verification system as defined in claim 6 additionally comprising a fiber optics image conduit mounted on said cart and positioned between the light source and the cell and conducting an image of the document from the document to the cell.

Claim 9

A document verification system as defined in claim 5 additionally comprising a potentiometer coupling the output of said cell to the input of said first means and making possible adjustment of said given amplitude of the first means so that said first means will respond to a signal of the amplitude produced by a worn old genuine document but will not respond to lesser amplitudes.

Claim 10

A document verification system as defined in claim 8 additionally comprising a potentiometer coupling said integrating means to said switch and making possible adjustment of the number of pulses from said integrating means required to turn on said switch.

Claim 11

A document verification system comprising a photovoltaic cell, a light source, said photovoltaic cell including means for comparing a pattern of the document with the document itself to provide a variation in light to said cell, first means for receiving the output of said cell and for converting those portions thereof which are above a given amplitude into pulses of constant voltage of varying time duration which is determined by the time that said portions are above said amplitude, second means for differentiating the output of said first means to produce for each input pulse an output pulse that is constant in amplitude and time duration, integrating means for counting the output pulses of said differentiating means and producing an output directly proportional to the number of second means output pulses, and switch means receiving the output of said integrating means and arranged to be turned on by an output of given amplitude from said integrating means.

Claim 12

A document verification system comprising a photovoltaic cell, a light source, said photovoltaic cell including means for comparing a pattern of the document with the document itself to provide a variation in light to said cell, first means for receiving the output of said cell and for converting those portions thereof which are above a given amplitude into pulses of constant voltage of varying time duration which is determined by the time that said portions are above said amplitude, second means for differentiating the output of said first means to produce for each input pulse an output pulse that is constant in amplitude and time duration, integrating means for counting the output pulses of said differentiating means and producing an output directly proportional to the number of second means output pulses, and switch means receiving the output of said integrating means and arranged to be turned on by an output of given amplitude from said integrating means.

Claim 13

A document verification system as defined in claim 10 additionally comprising a potentiometer coupling the output of said cell to the input of said first means and making possible adjustment of said given amplitude of the first means so that said first means will respond to a signal of the amplitude produced by a worn old genuine document but will not respond to lesser amplitudes.

Claim 14

A document verification system as defined in claim 11 additionally comprising a potentiometer coupling said integrating means to said switch and making possible adjustment of the number of pulses from said integrating means required to turn on said switch.