Patent ID: 7595784

Claim:
A liquid crystal display apparatus comprising: a liquid crystal display composed of a pair of substrates, a liquid crystal layer laid between said pair of substrates, a plurality of electrode groups for applying an electric field onto said liquid crystal layer, and a plurality of active elements being connected with said electrode groups and having a plurality of sub-pixel structures; a backlight unit arranged for controllable light emission of a plurality of colors, for applying a ray of light of each color onto said liquid crystal display; a controller for controlling a change of display data of each color on said liquid crystal display and a quantity of each color ray of light emitted from said backlight unit, based on an output signal sent from a backlight sensor for sensing light emission of said backlight unit and a video signal of each color being inputted for displaying the corresponding image on said liquid crystal display; and a subtitle detecting circuit for detecting a subtitle displayed on the liquid crystal display; wherein said controller determines a conversion maximum gray scale point MAX in accordance with a result of an analysis of a video signal of each color to be inputted for displaying onto said liquid crystal display, changes said display data so as to convert said inputted video signal at the MAX into a signal at a gray scale in which a liquid crystal transmittance becomes maximum, and lowers a backlight luminance output into a luminance level indicated by the MAX in said input and output characteristic; wherein no conversion of a 0 gray scale signal of each color in said inputted video signal is executed with respect to the color with the highest MAX and the conversion of said 0 gray scale signal of the remaining colors is executed so as to make the 0 gray scale of each color equal to a 0 gray scale luminance level at which the MAX becomes the highest; and wherein if the subtitle is detected, said conversion maximum gray scale point MAX is determined on an analyzed result of a video signal excepting a signal portion corresponding with said detected subtitle.