温度对铁电液晶电调谐滤波特性影响的研究

Influence of temperature on electrically tunable filter properties of ferroelectric liquid crystal

在改变外加电场实现铁电液晶电调谐滤波中,由于铁电液晶的螺距和自发极化强度对温度变化很敏感,从而为铁电液晶电调谐滤波器的应用和准确度的提高带来了困难。从铁电液晶的螺距和自发极化强度与温度的关系出发,讨论了温度对铁电液晶双折射的影响,给出了铁电液晶电调谐滤波器的透射率随温度变化的关系式,并进行了数值计算。结果表明,温度升高时,透射率和带宽增大,透射峰波长向短波长方向移动,温度变化对铁电液晶电调滤波特性的影响远小于电场变化的影响。

The application and accuracy of improvement of electrical field tunable liquid crystal filter is difficult because the pitch and spontaneous polarization of ferroelectric liquid crystals are sensitive to temperature where the molecular direction is changed by electric field. Based on the changing relation of pitch and spontaneous polarization of ferroelectric liquid crystal vs the temperature, the effect of temperature on birefringence of ferroelectric liquid crystal was discussed, the approximate formula of the transmission rate of ferroelectric liquid crystal electrically tunable filter properties according to the temperature was obtained. The effect of temperature on ferroelectric liquid crystal electrically tunable filter was numerically calculated. The results show that the transmission rate and band width increase and transmission peak wavelength moves to short wavelength as temperature increase, the effect of temperature changing on electrically tunable filter of ferroelectric liquid crystal is less than that of electrical field＂ changing.