Measuring Thickness and Pretilt in Reflective Vertically Aligned Nematic Liquid Crystal Displays

Cerrolaza Martínez, Beatriz and Geday, Morten Andreas and Otón Sánchez, José Manuel and Bennis, Noureddine and Quintana Arregui, Patxi Xabier (2008). Measuring Thickness and Pretilt in Reflective Vertically Aligned Nematic Liquid Crystal Displays. "Molecular Crystals and Liquid Crystals", v. 494 ; pp. 222-230. ISSN 1542-1406. https://doi.org/10.1080/15421400802430331.

Description

Title: Measuring Thickness and Pretilt in Reflective Vertically Aligned Nematic Liquid Crystal Displays
Author/s:
  • Cerrolaza Martínez, Beatriz
  • Geday, Morten Andreas
  • Otón Sánchez, José Manuel
  • Bennis, Noureddine
  • Quintana Arregui, Patxi Xabier
Item Type: Article
Título de Revista/Publicación: Molecular Crystals and Liquid Crystals
Date: 2008
ISSN: 1542-1406
Volume: 494
Subjects:
Freetext Keywords: pretilt angle; residual twist; vertically aligned nematic
Faculty: E.T.S.I. Telecomunicación (UPM)
Department: Tecnología Fotónica [hasta 2014]
Creative Commons Licenses: Recognition - No derivative works - Non commercial

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Abstract

Pretilt angle is a parameter of the utmost importance in the ultimate performance of vertically-aligned negative nematic LC displays. When these devices work in reflective mode, as is the LCOS microdisplays, accurate measurement of pretilt angles becomes a difficult problem, since usual experimental setups based on retardation of the polarization components of the impinging light are proportional to the product effective birefringence (neff - no) times thickness, and any attempt to separate these variables is cancelled out by symmetry. This work shows a relatively simple method capable of separating both variables. An experimental setup specifically aimed at vertically aligned reflective cells has been prepared. At the same time, a simulation model has been developed taking into account the properties of actual reflective displays. Comparison between experimental and theoretical results shows some discrepancies that can be explained assuming that the LC profile contains a residual twist. Including that twist in the model, an excellent agreement between theory and experiment has been achieved. Matching of simulations and measurements yields to the separate determination of pretilt angle and thickness and gives good estimates for the residual twist angle.

More information

Item ID: 2819
DC Identifier: http://oa.upm.es/2819/
OAI Identifier: oai:oa.upm.es:2819
DOI: 10.1080/15421400802430331
Official URL: http://www.informaworld.com/smpp/title~content=t713644168
Deposited by: Memoria Investigacion
Deposited on: 21 Apr 2010 11:56
Last Modified: 20 Apr 2016 12:28
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