| 摘要 |
Conventionally, it is difficult to adjust the luminance of an LCD panel suitable for viewing a movie image. According to this invention, when a black belt detection circuit detects a black belt added above and below an image to be viewed, such as a letter box type video signal, a microcomputer generates a pulse signal P with a predetermined duty ratio, as a control signal to cause an inverter to lower the luminance of a backlight. Said inverter in turn change the duty ratio of a drive pulse output from a switching circuit based on said pulse signal, and the backlight decreases its luminance, making the luminance of the LCD panel suitable for viewing a movie image. Moreover, it is possible to display an image as it is based on an input image signal, thus allowing the original gray scale of the input video signal to be reproduce faithfully on the screen.
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