A novel adaptive dimming technique with X-Y channels for LED backlight system of LCD TVs

Abstract

A novel adaptive dimming technique with X-Y channels for light emitting diode (LED) backlight system of LCD TVs is proposed. It has matrix structured LED modules with row and column switches to control the brightness of individual division block. It shows local dimming effects such as reduced power consumption and high dynamic contrast ratio with even using much fewer number of LED drivers of proposed method than that of conventional local dimming method. Therefore, low cost and compact design of LED drivers can be achieved. This paper also contains a new adaptive dimming algorithm and image compensation technique for proposed system.

A local-dimming LED BLU driving circuit for a 42-inch LCD TV

“…The duty cycle of the dimming PWM signal is adjusted with a video processing algorithm, which analyzes the images to be shown on TV and determines brightness for each region. Controlling the brightness of the LED module for each area allows lower energy consumption than fixing every LED module at equal and maximum level of brightness [4]- [7]. …”

“…In connection with the recent trend of taking advantage of the merits of LED and using it as the light source for the BLU for LCD panels, several studies have been published on the means of improving and controlling BLU's color gamut [2], [3]. There are also researches being conducted to further reduce energy consumption by implementing multiple areas and applying dimming according to image characteristics based on LED's fast response time [4]- [7]. However, most of these studies are focused on analyzing images to determine the algorithm for dimming areas and the dimming level.…”

Video quality metric model of MSE for backlight power saving

“…In [1], the method finds the maximum pixel value of the block, and reduces the value by 50% to save energy. In [2], authors consider the distributions of R, G and B layers to perform backlight saving algorithm.…”

Differential illumination of regions of interest for power efficient video playback

“…Previous work in the domain of display power saving using adaptive dimming [3] and brightness and contrast scaling [4] in backlight systems of LCDs rely on analysis of the output pixel values. Typically they optimize a distortion metric which quantifies the image quality loss suffered due to backlight dimming.…”