实验三-水平配向样品之光电量测

實驗三-水平配向樣品之光電量測TA:Tinda.InstituteofElectronic-opticalscienceandengineering大綱一、目的二、儀器設備及材料三、理論原理四、實驗步驟InstituteofElectronic-opticalscienceandengineering一、目的學習水平配向樣品於電壓控制下穿透度之量測，藉以瞭解液晶轉向之物理與光電特性變化。InstituteofElectronic-opticalscienceandengineering二、儀器設備及材料儀器設備：自動電壓量測系統(波形產生器、數位電表、電壓放大器、GPIB介面卡、PC、光偵測器)、偏振片、氦氖雷射、光衰減片(NDF)、反射鏡、偏光顯微鏡、配向機、烤箱、ITO玻璃清潔設備、玻璃切割機使用材料：良好水平配向液晶樣品一片(由實驗二取得)。InstituteofElectronic-opticalscienceandengineeringLinearPolarization(a)若Δ之整數倍時,(b)若Δ之奇數倍時,任一沿z方向前進之線偏振光,其電場E(z,t)之偏振方向必平行於x-y平面,若Δ為相位差k=2/;=2/T三、理論原理InstituteofElectronic-opticalscienceandengineeringCircularPolarization(a)若Δ(-/2)m之整數倍時,(b)若Δ(/2)m之奇數倍時,;Δ為相位差振幅相等為InstituteofElectronic-opticalscienceandengineering外加電場對nematic相的影響

對一nematic相液晶外加一電場E，此時電場對系統之能量貢獻可寫為InstituteofElectronic-opticalscienceandengineeringU1U2VoffVonIndexEllipsoid:x2/no2+y2/no2+z2/ne2=1(Foranuniaxialcrystal:nx=ny=no,nz=ne)

=2nd/=π/245oEzExkdITOGlassesITOGlassesExEykBirefringenceofLC

z(opticalaxis)yx=x’noO

nenoInclinedplane

z’y’neff()none/(no2sin2+ne2cos2)1/2InstituteofElectronic-opticalscienceandengineeringInstituteofElectronic-opticalscienceandengineeringAnisotropicO

nenonP-waves-waveP-waves-waveIsotropicdABAB△Phase=kxdExperimentalapparatusformeasuringbirefringenceandphaseretardationofaparallelalignedLCcell.dITOGlassesInstituteofElectronic-opticalscienceandengineeringE–wavephase:O–wavephase:Phaseretardation:NormalizedlighttransmittanceT.x:anglebetweenthepolarizer&analyzer.β:anglebetweenthepolarizer&frontLCdirectors.InstituteofElectronic-opticalscienceandengineeringO

nenoDisplay:λ/2plateInstituteofElectronic-opticalscienceandengineering四、實驗步驟(1)先瞭解如圖(1)之自動電壓量測系統方塊圖之工作原理。InstituteofElectronic-opticalscienceandengineering(2)如圖(2)之實驗裝置架設圖所示，液晶樣品前後各放置一片起偏鏡P(設穿透軸與x軸夾+45度)與檢偏鏡A，氦氖雷射偵測光經過兩偏振片與水平配向液晶樣品(液晶導軸沿x方向)後，分別量測不同電壓值下兩種狀況時之穿透光強度T平行與T垂直。InstituteofElectronic-opticalscienceandengineeri