Apparatus and method for controlling liquid crystal display brightness, and liquid crystal display device

Abstract

An apparatus for controlling liquid crystal display brightness includes: a zone image grayscale determining section configured to determine grayscale values of pixels in a zone image data block under a predetermined rule according to a received image signal; a zone backlight value pre-obtaining section configured to pre-obtain a zone backlight value corresponding to the zone image data block according to the grayscale values; a zone backlight value gain section configured, when it is determined that the zone backlight value is above a first threshold, to multiply the zone backlight value with a backlight value gain coefficient to obtain a backlight value to which a gain is applied, corresponding to the zone image data block, and to output the backlight value to which the gain is applied, to a driver circuit of backlight source in a backlight zone corresponding to the zone image data block, to control brightness of the backlight source in the corresponding backlight zone as a result of driving, where the backlight value gain coefficient is more than 1; and a zone image grayscale compensating section configured, when it is determined that the zone backlight value is below a second threshold, to compensate for the grayscale values of pixels in the zone image data block using compensation coefficients respectively to obtain compensated image data for driving the liquid crystal panel, wherein the compensation coefficient is more than 1.