Voltage Holding Ratio (VHR)

VHR-200 Voltage Holding Ratio System

  • Affordable high precision VHR measurement of liquid crystal test cells
  • Fully automated VHR measurement system
  • Ideal for R&D investigation of alignment materials and liquid crystals
  • Compact and designed for ease of use in production environments
  • Includes a CU-100 for independent testing of system performance
  • VHRS acquisition software designed for Windows operating systems


The VHR-200 Voltage Holding Ratio Measurement System is a research and development tool designed to provide an affordable means for determining the VHR of liquid crystal test cells.

Voltage Holding Ratio (VHR) is a critical electrical parameter for liquid crystal displays (LCDs). VHR is a measure of the LCD ability to retain a voltage during the time between pixel updates (frame time). The VHR-200 has software adjustable drive pulse width and frame time.

LCD manufacturers evaluate and test many new alignment polymers and liquid crystals for LCDs. The type of alignment polymer and liquid crystal can have a dramatic effect on the VHR of the liquid crystal display and, therefore, manufacturers monitor VHR as part of their evaluation. It was for this purpose that the VHR-200 was designed and engineered.

The VHR-200 Voltage Holding Ratio Measurement System includes such features as a laptop PC, CU-100 unit for independent testing of the system, and VHRS acquisition software for the Windows operating system. 

Elsicon is currently marketing the VHR-200 Voltage Holding Ratio Measurement System. If you are interested in discussing your VHR measurement needs please contact the representative listed below.


VHR-200 Specifications

DUT* Charging and Measurement Parameters

User selectable parameters via software
Output Scan Voltage: 1, 2, 4, 5, or 10Volts ( 5mV)
Charging Time: 64 or 512s (5%)
Output Frame Time: 0, 20, 50, 100, or 1000ms (0.5%)
Number of measurement cycles: 1, 2, 5, or 10 cycles
Pre-condition cycles prior to measurement: 0, 1, 2, 5 or 10 cycles

Fixed parameters
Samples per frame: 100

System Properties
Input capacitance: <50 pf
Input leakage current: 100 pA maximum
Source impedance: ~130 ohms
D/A card included for data acquisition and control of VHR-200
Dimensions (w/o computer): Height: 33mm, Length: 105mm, Width: 126mm 
Weight: 0.5Kg


VHRS Acquisition Software

Platform: Microsoft Windows operating system

VHR value: 0-0.999 (0-99.9%)

Features:

VHR calculation method based on RMS value

Oscilloscope like display of measurement cycles including cursor readout of the DUT voltage

Error indicators for unsymmetrical charging and offset in DUT voltage

Save DUT information and data to CSV file for further analysis using third party software
 


System Requirements

Voltage Requirements:   

VHR 200 is powered from the PC
100-120VAC, 50-60Hz, single phase for the PC

*DUT Device Under Test

Specifications subject to change without notice.


Contacts:

Wayne M.Gibbons
Elsicon, Inc.
Tel:(302)266-7030 ext.11
Fax:(302)266-7031
Email:wmgibbons@elsicon.com


 Last updated 9/28/06