各向同性相手性向列相液晶器件的制备与电光性能研究

Nowadays, flat panel display needs fast response speed and no difference of display characteristics for various viewing angle direction, blue phase liquid crystal display has excellent viewing angle and fast response speed because of the isotropic state under none bias voltage and the double helix structure with small pitch. However, it is very difficult into industrialization because the hysteresis is difficult to solve, the operating electric field strength is high and the residual birefringence is remained in the driven process, moreover, the narrow temperature range of blue phase and the complex fabrication process of the protrusion electrodes are other causes. In this project, our research focus on: (1) obtain the fabrication method of the stabilized isotropic chiral nematic liquid crystal device (ICN-LCD); (2) study the electro-optic characteristics of ICN liquid crystal and the influence of polymer monomer and nanoparticles, obtain the ICN-LCD without hysteresis, residual birefringence and low operating electric field strength; (3) establish the interaction energy formula between liquid crystal and polymer network (nanoparticle), the deformation formula of polymer network, study the polymer's deformation and nanoparticle's behavior under the operating electric field. Through studying ICN-LCD, we will obtain the preparation method of the stability isotropic chiral nematic structure, obtain the method which can low operating electric field strength and remove residual birefringence, propose new liquid crystal display modes, moreover, cultivate young techers and professional talents, facilitate the development of LCD industry.

蓝相液晶显示器满足现代平板显示器对快速响应和无视角观看差别的要求，其不加电压时的各向同性状态和小螺距双螺旋结构是优秀视角和快速响应特性的原因，但是因为难以解决"磁滞回线"，高驱动电场强度和残余双折射率的特性，以及难以控制的温度和凸起电极结构的复杂制造工艺，使其难以产业化。本项目中我们将研究：（1）获得稳定的各向同性相手性向列相液晶器件的制备方法；（2）研究各向同性相手性向列相液晶的电光特性，以及聚合物材料和纳米粒子的影响，获得无磁滞、无残余双折射率和低驱动电场强度的液晶显示器件结构；（3）构建聚合物网络和纳米粒子与液晶之间的相互作用能公式及形变表达公式，研究电场作用下的聚合物网络的形变和纳米粒子的行为。通过研究各向同性相手性向列相液晶器件，获得稳定各向同性相结构的制备方法，降低驱动电场强度和消除残余双折射率的方法，提出新型液晶器件，培养青年教师和专业人才，促进我国液晶产业的发展。

本项目针对光学各向同性液晶器件的电学特性和光学特性进行了详细的研究，主要研究内容包括：（1）光学各向同性液晶体系的弹性理论，通过分析该液晶体系中的指向矢分布特性，构建了大预倾角胆甾相液晶结构的一维弹性理论，实现了蓝相液晶的透射光谱的计算，胆甾相液晶和蓝相液晶的Bragg反射和旋光能力的计算，并构建了动力学方程，分析了该液晶体系中的响应机制问题；（2）理论研究证明高介电常数材料有降低驱动电压的功能，设计并获得了一种介电常数超过20的聚合物单体材料，可以提高Kerr常数70%；（3）对蓝相液晶显示器的电光特性进行了研究，在IPS电极结构中使用凸起结构，获得了低驱动电压特性，并设计电极结构，获得了更低驱动电压和低Gamma偏移的显示器结构，当凸起结构的介电常数提高后，驱动电压可降低到10V以下，并且液晶显示器的Gamma偏移小于0.1。研究结果对光学各向同性液晶体系的光学特性和电光特性有重要的指导意义，明确今后研究的主攻方向。通过本项目的研究，建立的弹性理论模型，也将在新型液晶器件设计中发挥重要的指导意义。