一种用于电子纸的电泳液的显示性能研究

Study on Display Character of Electrophoretic Liquid Used in Electronic Paper

用有机颜料汉沙黄(P.Y.3)、苏丹黑和合适的稳定剂为原料配制了一种性能稳定的电泳显示液。分析了此电泳显示液中颜料微粒的带电机理及其影响因素,研究了在改变电压方向时反射光谱与吸收光谱的变化及其原因,光谱分析结果表明体系中存在的各种吸附使显示效果受到局限,反射谱与吸收谱的变化在表征器件的显示特性时呈现出一致性,器件的反射光强和反射率在不同波长上有区域选择性,同时对比度也有区域选择性,这决定了在监测器件的响应时应选择的波长范围以及可利用的光源。兼顾灵敏性和测试信号强度的需求,选用峰值波长为470nm的蓝光二极管为光源,电泳槽的厚度为0.2mm,用荧光光谱仪监测相同周期不同幅值脉冲电压作用下颜料微粒在493nm波长处的反射光强的变化,并由示波器记录并输出反射光强随驱动电压的变化,还结合相关理论讨论了驱动电压对器件的反射光强和对比度的影响。

Organic pigments Hansa Yellow （P. Y. 3）, Sudan Black and right stabilizer were selected to prepare a new kind of electrophoresis. The stability was improved by adjusting the quantity of every component in the electrophoretic suspensions. The charging mechanism of the pigment and the influencing factors were analyzed. The change of the reflectivity and absorption spectrum with voltage direction was studied. Spectral analysis indicates all kinds of absorption confines the display effect. The absorption spectrum shows coherence with reflection spectrum about the display character. The reflection intensity of pigment as well as reflectance, contrast ratio, is different at different wavelength, which determines that a proper light source and radiating wavelength should be selected to monitor the response of display model to the added voltage pulse. In view of both sensitivity and signal intensity, Flurolog-3 fluorescent spectrometer was used to monitor reflection intensity change with pulsed voltage of different period and amplitude at the wavelength of 493 nm with a 470 nm blue light emission diode as light source and the thickness of the electrophoresis tank as 0.2 mm. An oscillograph was used to to record the change of reflection intensity with driving voltage. At last, the influence of driviing voltage on reflection intensity and response speed is theoretically analyzed.