Method and device for identifying documents

Claim 1

A method of identifying documents, comprising applying to the documents a multiplicity of machine-readable optical markings which characteristically modify incident light by either diffraction or refraction, wherein at least two different kinds of said markings which cause a different modification of incident light are arranged at least in pairs in a characteristic configuration on the documents, whereby said configuration is the same for all documents, storing information about said configuration in an identification device, cancelling out selected said markings on each document whereby at least one of the markings of the same kind is not cancelled, the geometrical position of the markings remaining on the document representing a piece of coded information, checking that the configuration of said remaining markings on the document coincides with the configuration information stored in the identification device, and if so, reading out said coded information.

Claim 2

A method of identifying documents, comprising applying to the documents a multiplicity of machine-readable optical markings which characteristically modify incident light by either diffraction or refraction, wherein at least two different kinds of said markings which cause a different modification of incident light are arranged at least in pairs in a characteristic configuration on the documents, whereby said configuration is the same for all documents, storing information about said configuration in an identification device, cancelling out selected said markings on each document whereby at least one of the markings of the same kind is not cancelled, the geometrical position of the markings remaining on the document representing a piece of coded information, checking that the configuration of said remaining markings on the document coincides with the configuration information stored in the identification device, and if so, reading out said coded information.

Claim 9

An apparatus for identifying documents, said documents having contained a multiplicity of machine-readable optical markings which characteristically modify incident light by either diffraction or refraction, said markings being of at least two different kinds each causing a different characteristic modification of incident light, and said markings being arranged at least in pairs in a characteristic configuration on the documents, whereby said configuration is the same for all documents, selected said markings having subsequently been cancelled whereby at least one of the markings of the same kind is not cancelled, the geometrical positions of the markings remaining on the document representing a piece of coded information, comprising: checking means for serially checking the authenticity of said remaining markings, said checking means comprising at least one light source and at least one light receiver; and a storage means in which information about said characteristic configuration is stored, said checking means being controlled by said storage means in such a way that said checking means supplies a signal whenever a said marking scanned by said checking means causes a modification of the light emitted by said light source, which modification is characteristic for the kind of that marking, whose stored configuration coincides with the configuration of the scanned marking.

Claim 10

An apparatus for identifying documents, said documents having contained a multiplicity of machine-readable optical markings which characteristically modify incident light by either diffraction or refraction, said markings being of at least two different kinds each causing a different characteristic modification of incident light, and said markings being arranged at least in pairs in a characteristic configuration on the documents, whereby said configuration is the same for all documents, selected said markings having subsequently been cancelled whereby at least one of the markings of the same kind is not cancelled, the geometrical positions of the markings remaining on the document representing a piece of coded information, comprising: checking means for serially checking the authenticity of said remaining markings, said checking means comprising at least one light source and at least one light receiver; and a storage means in which information about said characteristic configuration is stored, said checking means being controlled by said storage means in such a way that said checking means supplies a signal whenever a said marking scanned by said checking means causes a modification of the light emitted by said light source, which modification is characteristic for the kind of that marking, whose stored configuration coincides with the configuration of the scanned marking.