| 摘要 |
<p>PURPOSE:To automatically match the darkness and brightness of the items displayed in a display section to the illuminance of the circumference, by providing a control means which detects the illuminance of the circumference by means of an optical remote control photodetector and adjusts the brightness of the displaying items of the display section. CONSTITUTION:When the circumferential illuminance is high, an optical remote control photodetector 1 outputs a voltage as a signal. In this case, a momentary change in the circumferential illuminance or a noise component (alpha) by the optical remote control signal, etc., received by the optical remote control photodetector 1 is contained in the signal. Then the output of the photodetector 1 is inputted to a low-pass filter 11 through a buffer 12. The low-pass filter 11 outputs an illuminance signal F by averaging the above-mentioned signal. Therefore, the noise component (alpha) is removed. Thereafter, a comparator 13 compares the output of the low-pass filter 11 with a reference value and outputs a dark/ bright switching signal E as 'Low'. In accordance with the dark/bright switching signal E the luminous intensity adjusting section 7 of a clock deice 5 make the displaying content of a display device 9 brighter.</p> |
