An Output Channel Nonuniformity Compensation Driving Method in Flat Panel Display Driving Circuits

Modern flat panel displays, including thin-film transistor liquid crystal displays (TFT-LCDs) and organic light-emitting diodes (OLEDs), pursue more and more natural color expression. This requires the data driving system should produce very fine and accurate signal voltages or currents. Especially, the uniformity among channels of a driving system is critically important because the color or luminance differences among columns are easily noticeable. We propose a simple and efficient driving method for solving the artifacts caused by the existing nonuniformity among channels of a driving system, and confirms its impact by simulations using C-programming. The nonuniformity among channels mostly stem from the random offset of the output circuits of a driving system, which in turn is caused by the process variations. The proposed driving method shares N-output circuits between N-output channels such that the existing offsets of the channels are averaged out. Thus, the output signal error due to the offsets spreads out among the channels, improving the uniformity between the channels

I. Introduction

Beyond the data display applications like the laptop computer screen or PC monitors, flat panel displays are getting into the TV applications which form the biggest display market. Especially, the recent commencement of digital broadcasting forms a very favorable environment for flat panel displays, because it can be fully appreciated with large-screen TV sets. Plasma Display Panels (PDPs) have been considered a very promising display device for large-screen TV sets, but thin-film transistor liquid crystal displays (TFT-LCDs) have recently emerged as a display device of a very good choice for large-screen TV sets by successfully addressing their traditional shortcomings like viewing angle and response-time [1], [2]. In addition, even a 40-in diagonal organic light-emitting diodes (OLED) was announced, showing its good possibility as a large-screen TV.