sábado, 4 de janeiro de 2014
Design of Inverter for LCD TV Backlight with Flat Fluorescent Lamp Jeongwook Hur
Design of Inverter for LCD TV Backlight with Flat Fluorescent Lamp Jeongwook Hur Department of Electronic and Computer Engineering Graduate School Dankook University Advisor : Professor Sungkyoo Lim ABSTRACT The liquid crystal display(LCD) TV market has been growing continuously and cost reduction is one of the biggest issues to increase its market share. The LCD needs backlight because it belongs to non emissive displays. The cold cathode fluorescent lamp (CCFL) and external electrode fluorescent lamp (EEFL) are widely used in backlight system for LCDs. But assembly of CCFL and EEFL backlight system is very complex. The flat fluorescent lamp (FFL) is a newly developed light source and it has a very simple structure. The LCD backlight can have a simple structure if the newly delvelop FFL is used as a light source. The backlight with FFL can be more cost effective than that of the backlights with CCFL or EEFL light sources. But the temperature behaviour of FFL backlights are different from the backlight with CCFL or EEFL light sources, which prohibits FFL backlight from being accepted as the backlight for commercial application. In this paper, the FFL inverter with level control block(LCB) circuit was proposed to overcome the operation of FFL at low temperature. The inverter using LCB was developed to drive LCD TV backlight system using FFL light source with reliability at all temperature range of operation. The electro-optical characteristics of the FFL backlight showed substantial improvement by driving FFL backlight with inverter adapting LCB circuit. The FFL striking time, the time for brightness stabilization, and FFL lamp current were able to adjusted so that it was possible to operate the LCD TV backlight using FFL light source with stability at wide temperature range.