Abstract: A clock sent from a clock generator is subjected to frequency division by a plurality of frequency dividers responsible for different fractions of an input frequency. A switch selects and outputs any of the outputs of the plurality of frequency dividers, and thus varies the frequency of the clock within one horizontal scanning period. The clock is used to sample a video signal, whereby an image to be displayed on a liquid-crystal panel can be compressed or stretched according to a position in the horizontal direction of a screen. Thus, it can be prevented to give a sense of incompatibility even when a video signal indicating an aspect ratio different from the aspect ratio of the screen is displayed.

Abstract: An apparatus for driving a liquid crystal display can receive and adjust to image signals from one of a plurality of image signal formats such as those of the HDTV and NTSC systems, and includes plural shift registers, a sampling and holding (S/L) circuit and a Y driver. When receiving an image signal in the HDTV system, the shift registers receive and shift that image signal in series, and supply each bit data shifted thereby in a horizontal period to the S/L circuit. When receiving an image signal in the NTSC system, the shift registers are functionally divided into one for shifting that image signal and the other for shifting another image signal provided for displaying some pattern, and each bit data of these image signals is supplied to the S/L circuit. The S/L circuit provides the received data for driving data electrodes of the display, while the Y driver drives scanning electrodes of the display.

Abstract: A projection type imaging display system utilizing a liquid crystal panel projector. The zoom position of a projection lens is detected as an indicator of the aspect ratio of the main image being projected. Based on the zoom position, the position of an information display signal superimposed upon the main image is adjusted relative to the position of the main image, so that the information display signal is displayed on the main image no matter what the aspect ratio of the main image is.