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:
Feb. 01, 2005
Filed:
Feb. 12, 1993
I-fu Shih, Los Alamitos, CA (US);
David B. Chang, Tustin, CA (US);
I-Fu Shih, Los Alamitos, CA (US);
David B. Chang, Tustin, CA (US);
Raytheon Company, Waltham, MA (US);
Abstract
A method of marking and identifying an object () by the marking consists of applying to an object () an up-conversion material (), then irradiating the object () with infrared electromagnetic radiation () and, finally, observing the irradiated object to detect the spectrum of emitted electromagnetic radiation (). A suitable up-conversion material () is selected from a group of up-conversion materials consisting of CaF, BaF, CdF, LaFand SrFdoped with erbium, praseodymium, neodymium or dysprosium. The objects () may be observed to detect emitted electromagnetic radiation () from that part of the electromagnetic spectrum that is visible to the naked eye. The objects () may also be observed to detect specific wavelengths of electromagnetic radiation which are known to be emitted by the up-conversion material () when the up-conversion material () is irradiated by designated wavelengths of infrared electromagnetic radiation. The irradiating infrared radiation () may be encoded by modulation so that identification may be made by detection of the encoded modulation in the radiation emitted () from the up-conversion material ().