| Liquid crystal(LC)is an optical material that has both the fluidity of liquid and the anisotropic of crystal.With the development of technology,LC devices have been widely used in many fields,such as displays,sensors,filters,and lasers.However,the response time of traditional LC displays is usually in a few milliseconds or even a dozen milliseconds.Slow response time is still one of the main factors to restrict the development of LC materials and devices.Fast response LC materials and devices have become the research focus of LC optoelectronics.Sphere phase LC(SPLC)is a new type of LC material with microsecond response time.It is a self-assembled liquid crystal material induced by chiral molecules.The thermal stability of SPLC has been improved effectively by using polymer network.However,the high driving voltage,hysteresis,and residual birefringence are caused by the chail doping material with large helical twisting power and polymer materials.The main contents of this paper are as follow:1.Experimental research on the characteristics of polymer-stabilized SPLC(PS-SPLC)devices.We studied the influence of dielectric constant,LC thickness,polarization of incident light,and dye doping on the electro-optical(EO)properties of PS-SPLC devices.The method to effectively reduce the driving voltage and increase the contrast ratio of the device was obtained.Increasing the dielectric constant of LC and dye doping could reduce the driving voltage of the device;doping 5CB could obviously enhance the scattering state of the device.In addition,a smart window with good EO characteristics and thermal stability was proposed by using this LC material system.2.Theoretical study on EO properties of PS-SPLC devices.In order to overcome the shortcomings of the extended anomalous diffractiong approach model in describing the EO curve of the PS-SPLC devices,the extend Kerr effect was introduced in disclinations to show the relationship between the birefringence and applied electric field.A theoretical model which could accurately describe the EO properties of PS-SPLC devices was proposed and was named depolarization extended anomalous diffractiong approach.The EO characteristics of PS-SPLC devices were simulated by using Matlab software.Good agreement achieved between the experimental and simulated results.It lays a theoretical foundation for the development of new polymer stabilized LC devices. |
