The Effect Of Doping On The Electro-optical Characteristic Of Lcd And Research

Flat panel display is playing an essential part in the world, especially in the aspectof Liquid Crystal Display (LCD). For LCDs, if the response time of the liquid crystal isnot fast enough, the video image display would not coherent and lag behind, whichcould also greatly affect the displaying effect and the viewing comfort. So the responsetime of the LCDs is a particularly essential indicator to measure the quality of the videoof the dynamic display.This dissertation discussed mainly about response time of the liquid crystal. Thedissertation first introduced the basic concepts of the response time, then on this basis,the usual way to improve the LC’s response time were introduced. The dissertation hadproposed two methods of doping into LC to improve the response time: one is to dopenano-Ag particles in the LC, the other is to dope polymer into the LC.When the nano-Ag particles were doped into the LC, charge accumulation wouldbe generated at the interface of the medium under the applying of the electric field.Then the appearance of the charge accumulation would lead to the Derby type dielectricdispersion. It could also lead to the improvement of the response time. Besides, it is alsofound that the doping of nano-Ag particles could get the characteristic of thefrequency-dependence (with the change of frequency, there will be changes happeningin the electro-optical effect in liquid crystal), when let the LC response in the state offrequency modulation, the response time of the LC would be even faster, which couldbe explained by the Maxwell-Wagner effect.Besides, in order to improve the response time, the doping method of dopingpolymer into the LC was also be introduced. The dissertation commence the study fromtwo aspects: PNLC (Polymer Network Liquid Crystal) and PDLC (Polymer DispersionLiquid Crystal). The dissertation first introduced the display principle and preparationmethod of PDLC and PNLC, on this basis, the electro-optic properties of PDLC andPNLC could be changed by changing the preparation conditions (exposure temperature、the thickness of the film and the doping concentration of the polymer etc.). Thecharacteristics of response time could also be changed with the changing of preparation method. Then a better optimization method could be got by comparation.In this dissertation, the two doping methods were introduce from the aspect oftheoretical analysis and experimental analysis, which were all reach good optimizationresults.