CCFL backlight solution for low-cost liquid crystal televisions without image artifacts

Abstract

Recently, a single-phase CCFL (cold cathode fluorescent lamp) driving method has been adopted to provide a low cost implementation. However, whereas dual-phase driving compensates the coupling effect on the pixel electrodes, single-phase high voltage driving signals are coupled to pixel electrodes through parasitic capacitance between the lamps and panel electrodes. As a result, image artifacts appear on the display screen. This paper describes the analysis results of this phenomenon. Furthermore, the proposed automatic delay compensation scheme eliminates the artifacts caused by the coupling effect, regardless of how much delay is generated by the lamp driving circuit.