| 摘要 |
PURPOSE:To easily provide a thin type IC memory card with a write protecting function by boring a small light-transmission window in the case of the IC memory card and providing a means which detects light passed through the small window and a means which prevents the IC memory card from being rewritten according to the detection result. CONSTITUTION:The small window 3 which passes light is bored in the case, which has the means for detecting the light passing through the small window 3 and the means for preventing the IC memory from being rewritten according to the detection result. Then a photodiode D1 is arranged, for example, right below the small window 3. When the small window 3 is irradiated with natural light, etc., the memory IC 4 can be written and read freely through an external R/W terminal and when a seal, etc., is stuck on the small window 3 to cut off the light the IC memory is protected from writing.
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