Line-Time Extension Driving Method with Image Quality Enhancement for LCD Monitors and TVs

Abstract

This paper discusses an image quality issue of TFT-LCD monitors and televisions. To make jaggies invisible in TFT-LCD monitors, the resolution should be at least 200 pixels per inch (ppi), and the frame frequency of 120 Hz or even up to 240 Hz is used to express natural motion pictures in TFT-LCD televisions. The requirement of both high-resolution and high frame frequency decreases the available row line time, which necessarily leads to the insufficient pixel charging ratio. To address the insufficient row line time issue, the Line Time Extension (LiTEX) driving method was previously proposed that can extend the effective row line time. However, an image artifact such as, horizontal stripes is observed with the LiTEX driving method This paper analyzes the cause of the image artifact by building a TFT-LCD pixel model and performing HSPICE simulations, and proposes an improved version of the LiTEX scanning patterns. The experimental results indicate that the image artifact can be successfully remedied with the improved LiTEX driving method.