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:
Nov. 06, 2012
Filed:
May. 21, 2007
Hiroki Dembo, Kanagawa, JP;
Yoshiyuki Kurokawa, Kanagawa, JP;
Takayuki Inoue, Kanagawa, JP;
Semiconductor Energy Laboratory Co., Ltd., Atsugi-shi, Kanagawa-ken, JP;
Abstract
A position detection system is formed by network connection of a plurality of interrogators and a server. An RFID and the interrogators communicate wirelessly, whereby a distance from each interrogator to the RFID is searched to search a position of the RFID from the distance. In order to calculate the distance from the interrogator to the RFID, a signal is oscillated with a frequency corresponding to amplitude of a signal received in the RFID from the interrogator. A frequency of a signal oscillated in the RFID is detected in the RFID or by the interrogator, whereby a distance from the interrogator to the RFID is detected.