Locally pixel‐compensated backlight dimming on LED‐backlit LCD TV

Abstract

The pixel brightness of an LCD panel perceived by a user is the product of the backlight brightness and the panel transmittance. In conventional LCD panels, the backlight brightness is constant and always at peak luminance. This design suffers from light leakage and power waste problems at dark scenes. This paper presents a new LCD system, which uses locally pixel-compensated backlight dimming (PCBD). The proposed method combines backlight control and pixel processing for reducing light leakage and power consumption while keeping the image at the original brightness. Backlight luminance is dimmed locally in the dark-image region, and pixel values are compensated synchronously according to the luminance profile of dimmed backlight. By reducing the light leakage, a static contrast of over 20,000:1 has been achieved on a large-sized LCD panel with the proposed PCBD method. No obvious artifacts have been noticed as well. The power consumption of the panel can also be greatly reduced, depending on various video content. The PCBD method could be widely used for developing state-of-the-art LCD panels with LED backlights.

Flicker reduction in LED-LCDs with local backlight

“…This phenomenon creates an unnatural trembling in the backlight segment, which defines the flickering artifact and is caused by temporal local or global dimming. Some algorithms for flicker removal were proposed in the literature [8], [9]. The first algorithm uses Moving Average (MA) filter taking the average pixel values through several consecutive frames.…”

“…In Chen et. al [9], an Infinite Impulse Response (IIR) filter were proposed to smooth temporal backlight variation and eliminate flickering. This algorithm uses temporal and spatial backlight luminance to avoid flickering artifact [9].…”

“…al [9], an Infinite Impulse Response (IIR) filter were proposed to smooth temporal backlight variation and eliminate flickering. This algorithm uses temporal and spatial backlight luminance to avoid flickering artifact [9]. While most flicker removal methods are designed for a specific backlight algorithm, they can not be generalized to be used in other algorithms.…”

“…Chen et. al [9] proposed a first order IIR filter for flicker removal in which the filter coefficients are calculated using average values of the target image. In this paper, we propose an adaptive flicker-reduction algorithm for LED-LCDs with dynamic backlight.…”

Luminescence properties of PDP phosphors under high Xe-content gas discharge

“…3),6), 7) In response to the increased competition from LCD manufacturers, Samsung SDI Co., Ltd. launched fieldsequential stereoscopic 3D PDPs by improving the PDP response time using new phosphors. 8) However, the most crucial issue for PDP manufacturers is that thus far, the luminous efficiency of PDPs has remained low.…”