彩色电子纸的基础物理与操作原理

电泳式电子纸作为一种重要的反射式显示技术,已被广泛应用于电子阅读器等低功耗的显示器件中。单色电泳式电子纸从实验室走向产业化的成功催生了彩色电子纸的发展,以满足人们对反射式显示器的多样需求。然而,在成功实现彩色化之前,还有许多挑战性的问题仍待克服。为了实现电子纸的彩色化显示,本文首先介绍电泳式电子纸的基本操作原理、包括粒子带电机制,粒子表面改性等。然后,针对电子纸在驱动过程中产生的"鬼影"现象和反射率峰突现象进行了驱动波形的分析设计与优化,消除了峰突的同时仅牺牲了4%的峰值反射率。最后,我们对电子纸彩色化方案进行讨论,并首次提出将转印工艺技术与电泳式电子纸相结合,成功制备了边长为300μm的方块彩色微胶囊子像素阵列,实现了空间混色的彩色电泳式电子纸,测得其NTSC的色域在三色子像素结构下为13.7%,较于已报道的基于CF彩色电子纸的3.14%有明显提升。

Fundamental physics and operational principles for full-color e-paper

As a promising reflective display technology, electrophoretic display (EPD) has been widely applied in low power consumption display devices such as e-reader. Despite of the commercial success of monochromic EPD, the future display application needs to be full-color. However, some challenges still obstruct the development of commercial full-color EPD. This paper will first introduce fundamental operation mechanism of EPD, such as particles charging mechanism and particles surface treatment. Then the driving waveform is discussed to improve EPD's performance in order to resolve the ghosting and reflectance overshooting phenomenon. We managed to eliminate the reflectance overshooting at the cost of only 4% of the peak reflectance. Also, different strategies for achieving full-color EPD are presented as well as a transfer method. We successfully prepared 300×300 μm color microcapsules sub-pixel array and realized a color electrophoretic EPD. The NTSC ratio of our EPD reached 13.7% for three subpixels structure, which is larger than 3.14% of the color filter based EPD reported elsewhere.