Display device for motor vehicles

Claim 1

Display device for displaying a succession of images in a motor vehicle, comprising a graphic-capable transflective dot matrix LCD (19); means (21) for backlighting said LCD, and a Liquid Crystal Display (LCD) control circuit (17), having an output connected to and controlling said LCD, said control circuit including driver stages electrically activating matrix dots or pixels (22,25) of said LCD, memory means in said control circuit for representing information as one of said images on said LCD by brightness contrast including instructions to said drivers for applying a voltage to certain activated matrix dots, as opposed to the remaining non-activated matrix dots, to which no voltage is applied, means in said control circuit for comparing, in each successive image to be displayed on said LCD, the number of activated matrix dots or pixels to the number of non-activated matrix dots or pixels, in order to use the result of this comparison as a factor in automatic selection of a contrast mode, and means (27) for selectively setting said display, under conditions of bright ambient lighting, to a positive contrast mode in which a majority of pixels in said image are bright, thereby assuring adequate legibility of said information, and under conditions of dim ambient lighting, to a negative contrast mode in which a majority of pixels in said image are dark, thereby preventing dazzling of a vehicle operator.