VRCx_ex25.in : Vertical Alignment Liquid Crystal Display - Simulation versus Measurement

Home> Victory RCx>

VRCx_ex25.in : Vertical Alignment Liquid Crystal Display – Simulation versus Measurement

Every software package contains a full set of examples suitable for that version and are installed with the software. If you see examples here that are not in your installation you should consider updating to a later version of the software. These examples can be used by beginners and advanced users for product evaluation, teaching purposes, and self-training.

Required Modules

Victory Process

3D Structure Editor

Victory RCx

In this example, we will demonstrate how to simulate the dynamic LCD response using VictoryRCx LCD model and compared with reference data. In dynamic LCD mode, LC directors’s response to input signal is the key point in a given Liquid Crystal material and electrode configuration. To get the time response of LC material, we employ VA(vertical Alignment) IPS(In-Plane-Switching) mode configuration. VA IPS LCD structure have three pixel electrodes at the same plane and two common electrode at the bottom surface. Two common electrode is grounded and two pixel electrodes are biased with same polarity. the central pixel electrode(pix2) is biased on opposite polarity of “pix1 ” and “pix3 “.
Build 3D LCD structure using process simulator.

First part of input is to make a 3D simulation structure using Victoryprocess process simulator. SPECIFYMASKPOLY statement define three pixel electrode and two common electrode which are normally grounded to zero. In Victoryprocess, Liquid crystal material is defined as user-defined material name “LC ” and it is recognized as a liquid crystal material in VictoryRCx with liquid crystal parameters. Generated three dimensional VA(Vertical Alignment) IPS(In-Plane-Switching) mode LCD structure can be plotted. It consists of three Pixel electrodes at the top and two common electrodes at the bottom. User can simulate different gap, width of electrodes, and thickness of liquid crystal by modifying the value of ‘g’, ‘w’, and ‘lc_thick’ variable. The dimension of x is defined by “xmin ” and “xmax ” variable and ymin/ymax control the dimension of y.

Electrical & Optical simulation of LC is performed in VictoryRCx.

First, we have to define LC’s anisotropic permittivity, elastic constant, and rotation viscosity.

SETPIXELBIAS( “pix2 “, 0,-0.5,-1,-1.5,-2,-2.5,-3,-3.5,-4,-4.5,-5,-5.5,-6,-6.5,-7,-7.5,-8) vmaxtrap=5

which describes static dc bias on “pix2 ” electrode. It starts from 0 and end with -8 Volt

INTERCONNECT capacitance structure= “VRCx_ex25_dc ” domainboundarycondition=cyclic skipcap

performs dc static analysis in a given pixel voltage by SETPIXELBIAS command

SETDYNAMICPIXBIAS pixelfile= “VRCx_ex25_0.dat “
it describes time pulse data from measurement file or other emulator.

INTERCONNECT capacitance structure= “VRCx_ex25_tran ” domainboundarycondition=cyclic skipcap
performs field solver calculation and save to file at each time. VictoryRCx appends .T’time’ VRCx_ex25_tran filename at each time solution.

After getting solution for dc and transient, we plot voltage versus transmittance and contour of transmittance in each case.

To get optical properties of LC’s response during time pulse, we assumed crossed linear polarizers. “Optics ” statement calculates the transmittance in given optical properties of material. To plot transmittance versus voltage, we extracted average transmittance value at DC bias and it is saved to VRCx_ex25_2.dat file. Finally, tt is compared to measurement data (VRCx_ex25_2_exp.dat).

Finally, we plotted the time versus transmittance curve by assuming user-define input pulse(VRCx_ex25_0.dat). It show typical transient behaviour in rise time and falling time even symmetric steep input pulse is applied.