Composite multi-frequency oscillation driving for enhanced dynamic grayscale stability in electrophoretic displays

Electrophoretic displays (EPDs) occupy a unique position in display technologies due to their distinctive reflective operation and bistable characteristics. However, charged particles in the suspension medium tend to form agglomerates under van der Waals forces, significantly impairing particle mobility. This compromises precise control of particle motion through driving signals, leading to grayscale drift and dynamic response hysteresis. Conventional rapid-display driving waveforms with single-frequency oscillation fail to adequately activate particles. To overcome this limitation, we propose a composite multi-frequency oscillatory driving method. By sequentially applying high-frequency and medium-frequency oscillation waveforms, this approach achieves efficient disaggregation of particle agglomerates and precise particle positioning, demonstrably enhancing grayscale accuracy and image quality in EPD video applications. For grayscale rendering, the proposed method achieves a 40.462% reduction in average color difference (ΔE) and superior four-grayscale uniformity compared to other techniques. In dynamic imaging, it elevates the structural similarity index (SSIM) and peak signal-to-noise ratio (PSNR) by 16.675% and 15.092% respectively. Consequently, these advancements substantially enhance video stability and image fidelity while expanding EPD's grayscale expressiveness, thereby enhancing its viability for high-quality imaging and video-intensive applications.