Patent ID: 6202932
Filing Date: 2001-03-20
Classification: G06K

Abstract:
A method of transferring energy, clock frequency and data from a host equipment to a smart card's semiconductor chip which is connected to the host equipment without an electrically conducting contact, comprising the steps of:transferring energy to the smart card as optical radiation from at least two distinct light sources;varying light intensity of each of the light sources periodically between maximum and minimum values in such a way that while a radiation intensity of one of the light sources goes from minimum to maximum, a radiation intensity of the other of the light sources changes accordingly from maximum to minimum so that total intensity of light emission remains essentially constant;transmitting the clock frequency via a cyclical alteration of energy transfer from the light sources wherein the alteration frequency of the radiation sources becomes the clock frequency for the smart card; andtransferring data as a modulation of the clock frequency.