Simulation versus Measurement

clex25.in : Simulation versus Measurement

Requires: Victoryprocess/Clever

Minimum Versions: VictoryProcess: 7.22.1.R/Clever 3.11.20.R
In this exampple, we will demonstrate how to simulate the dynamic LCD response using Clever 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 centeral pixel electride(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 Clever with liquid crystal parameters. Tonyplot3D plot show us generated three diemensional VA(Vertical Alignment) IPS(In-Plane-Switching) mode LCD structure. It consist 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 controll the dimension of y.


Electrical & Optical simulation of LC is performed in Clever.
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 describe static dc bias on "pix2" electrode. It starts from 0 and end with -8 Volt
    Interconnect Capacitance structure="clex25_dc" domainboundarycondition=cyclic skipcap
  • perform dc static analysis in a given pixel voltage by "setpixelbias" command

setDynamicPixBias pixelfile="clex25_0.dat"

  • it describe time pulse data from measurement file or other emulator.
    Interconnect Capacitance structure="clex25_tran" domainboundarycondition=cyclic skipcap
  • performs field solver calculation and save to file at each time. Clever appends .T'Time' clex25_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 calculate 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 clex25_2.dat file. Finally, tt is compared to measurement data(clex25_2_exp.dat).
Finally, we plotted the time versus transmittance curve by assuming user-define input pulse(clex25_0.dat). It show typical transient behavior in rise time and falling time even symmetric steep input pulse is applied.

To load and run this example, select the Load example button in DeckBuild. This will copy the input file and any support files to your current working directory. Select the run button to execute the example.