Patent ID: 7034895

Claim:
An image display apparatus which has a light source whose quantity can be controlled, and displays an image based on a video signal externally input after partially passing through or reflecting a light from the light source, comprising: light quantity control means having a predetermined scope of an output level corresponding to a scope of control of light quantity of the light source, and for outputting a reference signal at a level arbitrarily set by a user; level control means for detecting an average brightness of the displayed image according to the video signal, and for controlling a level of the reference signal output from said light quantity control means depending on the detected brightness; and control means for controlling light quantity of the light source according to the signal controlled by said level control means; wherein said level control means lowers the level of the reference signal when the detected brightness is low; wherein said external video signal is input in a frame or field unit; and said level control means comprises; average luminance level detection means for detecting an average luminance level of the video signal in said frame or said field unit, and outputting an amplification coefficient depending on the detected average luminance level; and multiplier means for multiplying the reference signal by an amplification coefficient output from said average luminance level detection means.