| 摘要 |
PROBLEM TO BE SOLVED: To automate locking of a key of the portable equipment and its release and activating lighting of a back light and the key only when the surrounding is dark. SOLUTION: When an output voltage from a photo sensor 2 is higher than a reference voltage V1, a key lock release device 10 releases key locking. Furthermore, when a photo sensor output voltage is higher than a reference voltage V2, a lighting extinguishment device 11 interrupts lighting of a key and a back light of a display device. |
