| 摘要 |
PURPOSE:To lengthen the life of a display unit and to heighten safety by providing an automatic controlling circuit in the brightness controlling section of a keyboard display unit. CONSTITUTION:A keyboard display unit consists of a keyboard 1, a display unit 2 and a brightness controlling section 3 having an automatic controlling circuit 31. The function of the automatic controlling circuit 31 is stopped by the brightness controlling section 3, and the brightness of a cathode-ray tube of the display unit 2 is optimized. When the automatic controlling circuit 31 is operated next, the automatic controlling circuit 31 always monitors inputs from the keyboard 1. If there is no input from the keyboard for a fixed time, the brightness of the cathode-ray tube of the display unit is lowered, and if there is an input from the keyboard 1 when the brightness of the cathode-ray tube is lowered, the brightness is returned to former optimum brightness.
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