Power transmission of a desk with a cord-free power supply

The battery is an indispensable component of portable electronic equipment, but charging is often inconvenient. A contactless electric power supply, such as the desk-type contactless power station (CLPS) we propose, significantly improves the ease of charging such equipment. In this system, primary coils are embedded into the desk surface to efficiently supply electrical power to portable equipment placed on the desk. Only the primary and the secondary coils facing each other work as a power transmitter. We have confirmed that electric power transmission with efficiency of 85 /spl plusmn/ 5% can be attained anywhere on the desk. This examination reveals the effectiveness of using several primary coils.