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:
Mar. 04, 1997
Filed:
Mar. 08, 1995
Hitachi Maxell, Ltd., Osaka-fu, JP;
Maxell Seiki, Ltd., Kyoto-fu, JP;
Abstract
A fluorescent light emitted from a marking containing at least one fluorescent substance is detected by illuminating the marking with an exciting light having an intensity that varies at a predetermined cycle, converting a change in intensity of light reflected from a position where the exciting light is irradiated into a varying electric signal and selectively extracting from the converted electric signal, only an electric signal component having a frequency matching with but a phase displaced from, that of a signal component corresponding to light reflected from the marking. A fluorescent detecting apparatus for this purpose includes a light source for irradiating at an irradiating station a marking formed on a medium with rays of light having an intensity that varies cyclically, the marking having at least one fluorescent substance. The apparatus further includes a photo-electric detector for detecting incident rays of light reflected from the irradiating station and converting the rays of light into an electric signal, and a phase detector for extracting from the electric signal respective signal components corresponding to the rays of light reflected from the marking and the medium, respectively.