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. 24, 1992
Filed:
Dec. 18, 1989
Theodore D Geiszler, Los Gatos, CA (US);
Dale Lindseth, San Martin, CA (US);
Indala Corporation, San Jose, CA (US);
Abstract
A proximity detection system which combines the advantages of an electrostatic (electric) field coupling mechanism with those of an electromagnetic coupling mechanism in order to overcome the disadvantages of the respective individual coupling mechanisms. The system includes a coded tag which is excited with an induction field, i.e., by using an electromagnetic coupling mechanism as has been done in the past in such proximity identification systems, but which transmits stored data back to the receiver using both an electric field coupling mechanism and an electromagnetic field coupling mechanism. The receiver, in turn, is provided with a novel preamplifier circuit arrangement, so that it can simultaneously receive signals via either or both of these coupling mechanisms.