Method of capacitively reading coded cards and device for carrying out such a method

Abstract

Abstract The transmitter electrodes (12a, 12b) of a reading device are used for transmitting an RF signal (f1, f1) through a slot designed for a coded card (1) to receiver electrodes (12) on the opposite side of the slot, the signal (f2) received by the receiver electrodes (12) being modified by the effect of conductive dots (2) on the coded card (1). By this means, the maximum possible number of code combinations should be available on a coded card (1) and the code combination should be capable of reliable identification through the use of the smallest possible number of transmitter/receiver electrode pairs in the reading device. The transmitter electrodes (12a, 12b) which are arranged in sequence in the direction of insertion of the coded card (1) are used for the purpose of transmitting signals (f1, f1) the phases of which differ. The coded card (1) has conductive dots (2) which, when the coded card (1) is inserted between the electrodes, alternately transmit to the receiving electrode (12) the phase-differing signals (f1, f1) of the transmitting electrodes (12, 12b).

Inventors

• 👤 Jukka Korhonen
• 👤 Teijo Viljanen

Bibliographic Details