This paper presents a pixel compensated backlight dimming method for improving contrast on LED-LCD. The backlight luminance is dimmed locally along with image contents, and pixel values are compensated synchronously according to the luminance profile of dimmed backlight. Static contrast above 20000:1 has been achieved on a large size LCD with the proposed method and no obvious artifacts are observed.

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.

We propose a new frame rate upconversion algorithm using the wavelet transform. In the proposed scheme, motion estimation is performed using the information in the wavelet-transformed subbands. In addition, an effective compensation method for the occlusion areas, called overcompensation, is presented. Computer simulation shows a higher performance of the proposed upconversion scheme than conventional methods.

This study looks at optimizinge light redistribution to improve the overall illuminance uniformity of commercial IRED modules. To obtain uniform illumination over a prescribed rectangular area, a freeform surface lens was evaluated using TracePro. The LED light overall illuminance uniformity regulated in KSC 7658 was verified using Relux software. Experimental test results showed 0.81 overall illuminance uniformity for rectangular light distribution of LED lights having a radiation angle of 80°. After fabricating prototype IRED lights based on these simulation results, illuminance performance was observed when used as actual IRED lighting with a nighttime CCTV system. Image observation photographs of the prototype 80° rectangular IRED lights confirmed that object images can be seen clearly owing to high overall illuminance uniformity, and that dark regions of the CCTV screen were not shown.

We investigated the electrical and optical characteristics of the panel with MgO films prepared by ion plating with different source materials of poly-crystal and high-purity single-crystal pellets and reported remarkable improvement in temporal image sticking and luminous efficiency by using a high-purity singlecrystal MgO.