Currency validator using a photocoupler for image recognition using cylindrical lens

Claim 1

A currency validator comprising: means for advancing currency in the form of a bill along a predetermined path from a source to a bill stacker, a photocoupler for image recognition including a case having a pair of apertures in juxtaposed relation positioned along said path, a light emitting element positioned in one of said apertures, a light sensitive element positioned in the other of said apertures, a cylindrical lens having an elongated flat surface facing both said elements, a convex surface of said lens facing outwardly of said case, said cylindrical lens being positioned normal to the path traversed by said bill, said cylindrical lens being spaced vertically from a portion of said path thereby defining a space therebetween, and a transparent plate means positioned beneath said lens, said plate means having a flat surface facing said bill whereby said plate means (a) forms an optical path between said lens and said bill, (b) fills substantially the space between the said lens and said portion of said path, (c) precludes contact between said bill and said lens and (d) provides smooth passage for said bill minimizing wrinkling as the bill progresses past said case, whereby light emitted passes through said cylindrical lens and through said plate means, is reflected by said bill, returns through said plate means and said cylindrical lens and is received by said light sensitive element.