| 摘要 |
PURPOSE:To improve the operability and visibility for a user without consuming unnecessary power. CONSTITUTION:An illuminating device 3 for illuminating at least one of a key operation part 2 consisting of number keys, function keys, etc., and a numeral display device 1 is provided and a current flow flowing into the device 3 is adjusted by a current control circuit 8 in accordance with the output of a photodetecting element 7 for detecting the brightness of its periphery and converting the detected result into an electric signal. On the other hand, the ON/OFF of a current flowing into the device 3 is controlled by an output from a threshold circuit.
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