| 摘要 |
PROBLEM TO BE SOLVED: To provide a composite material having good thermal conductivity, small thermal expansion and shielding characteristics as a heat-radiation plate for an IC card. SOLUTION: In a card-type portable electronic device constituted of a built-in semiconductor element and information transfer means, a high thermal conduction layer 3 of copper or copper alloy and a low thermal expansion layer 1 of Fe-Ni group alloy are laminated alternately to form a multi layered structure with 10 or more layers, while a multi layered structure of 50 or more layers is preferably formed. Furthermore for the high thermal conduction layer 3, which sandwiches the low thermal expansion layer 1, a continuous substrate is provided via a plurality of through-holes 2 formed at the low thermal expansion layer 1. |
