奈米粒子掺雜雙穩態液晶元件之研究

Abstract

本研究利用液晶摻雜二氧化矽奈米粒子形成光散射之穩態效應的雙頻液晶元件。施加交流訊號時，液晶分子因轉動而破壞原先奈米粒子因氫鍵形成之網絡結構，因而形成一個新的具有規律性的網絡，即使將交流訊號移除時，此元件仍具有穩態的現象。我們的研究主要針對液晶元件施加不同的頻率、電場與訊號波形時，分析其對穿透度、閥值電壓、記憶現象與響應時間之光電特性影響，並利用雙頻液晶混合奈米粒子達成其雙穩態之顯示切換。 最後為了嘗試降低雙頻液晶之切換頻率，藉由化學合成方式選擇具有酯化官能基的正型液晶去完成所要雙頻液晶。

The electro-optical properties of liquid crystal devices based on light scattering have been investigated for nematic liquid crystal (LC) / nanoparticles (aerosil) composites. By applying ac electric field to the device , a normally scattering LCD become transparent due to LC molecules and aerosil network reorient toward the E-field. The former aerosil network is being broken and a new stable network is being formed. Besides, this transparent state is retained if the E-field is switched off. The influences of driving frequency、electric field and waveform on electro-optical characteristics of transmission, threshold voltage , memory effect and response time were studied. Then, we used the dual frequency liquid crystal /nanoparticles composites to switch the bistable mode. Finally, we tried a single ester positive compound to decrease the cross-over frequency of dual liquid crystal by the chemical synthetic method.