| 摘要 |
PROBLEM TO BE SOLVED: To provide a personal authentication medium, which is automatically turned into an unusable state. SOLUTION: When ordinarily using a card 2, the card is taken out of a dedicated case, used within a short time and immediately returned into the dedicated case. In this case, since a driving voltage is supplied from a charging/ discharging circuit 8 to a liquid crystal display part 4, a non-transparent state is maintained. When the card 2 is away from the dedicated case for a long time because of a loss or robbery, no driving current is supplied from the charging/discharging circuit 8 to the liquid crystal display part 4 and the display part becomes transparent. As a result, a character or pattern printed on a card base material for showing that the card 2 is unusable is made visible. |
