The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 19, 1990
Filed:
Oct. 26, 1988
Anthony Martin, Hampshire, GB;
Paul D Lacey, Hampshire, GB;
De la Rue Systems Ltd., , GB;
Abstract
Apparatus for detecting the presence of an ink on a substrate comprises a number of LEDs (1) for irradiating the substrate (2) with radiation at at least two different wavelengths, at least one of the wavelengths being chosen to correspond to an absorption or relectance wavelength of the ink to be detected. A sequence generator (5) modulates the radiation at each wavelength in a respective, different manner. A radiation sensor (3) senses radiation emitted by the substrate (2). A correlator (7,8) correlates samples of the sensed radiation from the radiation sensor (3) with signals each of which is modulated by a respective one of the modulations applied to the radiation, to generate correlation signals. A monitor (9) monitors the correlation signals in order to detect the presence of the said ink.