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. 15, 2005
Filed:
May. 07, 2003
Applicants:
Ifushi Shimonomoto, Okazaki, JP;
Takahide Kitahara, Kariya, JP;
Inventors:
Ifushi Shimonomoto, Okazaki, JP;
Takahide Kitahara, Kariya, JP;
Assignee:
Denso Corporation, Kariya, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04Q009/00 ; H04Q005/22 ; B60R025/00 ;
U.S. Cl.
CPC ...
Abstract
An electronic key system has a portable electronic key and a transmitter provided in a vehicle. The key and the transmitter have respective LC resonance circuits including antenna coils that can be electromagnetically coupled. The portable device has a charge capacitor and a diode. The capacitor is charged with a voltage induced by the coil when the LC resonance circuit resonates. The electronic key is enabled to communicate with the transmitter with the charged voltage of the charge capacitor when a built-in battery runs down.