Keyless entry system for automotive devices antenna device allowing low power radio signal communication
US4973958A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 21, 1986 |
| Grant date | Nov 27, 1990 |
| Priority date | — |
| Expiry date | Feb 21, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG07C2009/00793
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A keyless entry system employs a pocket-portable radio signal transmitter to be carried by a user and a controller mounted on a vehicle and associated with a vehicle device, such as a door lock mechanism, a trunk lid opener, a window regulator, a steering lock device and so forth, to be operated. Radio signal communication between the transmitter and the controller is performed by electromagnetic induction. According to the present invention, electromagnetic induction is caused between antennas in the transmitter and the controller. In order to provide wide communication area, at least the antenna of the controller serves as a transformer to generate higher loop current for generating sufficiently strong magnetic field therearound.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.