Cheol-woo Park

13.3 Co‐Optimization of Color AMLCD Subpixel Architecture and Rendering Algorithms

Color subpixel rendering is enhanced by co-optimizing the color subpixel architecture and algorithms with respect to human vision, resulting in the PenTile Matrix™ subpixel architecture to double the addressability and the MTF limit in both horizontal and vertical axes while reducing driver count. Results of prototype AMLCD panels demonstrate improved text and full color image quality.

51.2: Reducing Gray-Level Response to One Frame: Dynamic Capacitance Compensation

A novel driving scheme, named Dynamic Capacitance Compensation (DCC), for active-matrix (AM) LCDs was developed. It takes the charge-&-hold nature of AM-LCDs into consideration to enhance the switching speed. By incorporating DCC and faster liquid crystal, a TFT-LCD whose response time was less than 10 ms for all gray levels with the on + off time of 8.4 ms was developed. DCC can be applied to any kind of LCD modes to reduce the gray response time to less than 1 frame.

9.2: Implementation of RGBW Color System in TFT‐LCDs

Last year, we introduced a TFT-LCD with RGBW color system. The primary advantage of the RGBW system is that its optical efficiency is at least 50% higher than the RGB system. However, it is not a simple task to incorporate the new color system into the existing infrastructure of the RGB system: the driving circuitry, fabrication of color filter, and color conversion. In this report, the practical hurdles are discussed and the solutions are presented.

29.4L: Late‐News Paper: Image Synchronized Brightness Control

A novel image synchronized brightness control (ISBC) method for active matrix liquid crystal display (AMLCD) was developed, where automatic modulation of the backlight luminance is performed according to the gray distribution of image data. The ISBC can deliver a peak luminance of 500 ∼ 600 nits, which is very comparable to that of cathode ray tubes (CRTs) and is 2 to 3 times higher than that of normal LCD. The dynamic CR is over 700. With this ISBC method we can display a vivid moving image, while maintaining the same level of power consumption and a backlight.