| 摘要 |
<p>PURPOSE:To automatically set the brightness of electronic video at an optimum value with respect to the brightness of the outside, to use the device for a long time by saving energy consumption and to reduce the burden of eyes by providing a means to detect the brightness of the outside and a means to adjust the brightness of electronic video, setting an initial value for the brightness of electronic video according to the brightness of the outside, and lowering the brightness of electronic video to a prescribed level with time during video observation. CONSTITUTION:Signals from a photosensor 5 are inputted to a video brightness control circuit 7 and a time counter circuit 8 and corresponding to the signal level, the initial brightness of video is decided. At the same time, the time counter circuit 8 is started, and the display of video sent from a source program presenting part 9 is started as well. The change of video brightness with time is controlled by the time counter circuit 8 and the video brightness control circuit 7 along the darkness adaptive curve of the eyes.</p> |
