An Optical Method for Pretilt and Profile Determination in LCOS VAN displays

Cerrolaza Martínez, Beatriz and Geday, Morten Andreas and Quintana Arregui, Patxi Xabier and Otón Sánchez, José Manuel (2010). An Optical Method for Pretilt and Profile Determination in LCOS VAN displays. "Journal of Display Technology", v. 7 (n. 3); pp. 141-150. ISSN 1551-319X. https://doi.org/10.1109/JDT.2010.2050857.

Description

Title: An Optical Method for Pretilt and Profile Determination in LCOS VAN displays
Author/s:
  • Cerrolaza Martínez, Beatriz
  • Geday, Morten Andreas
  • Quintana Arregui, Patxi Xabier
  • Otón Sánchez, José Manuel
Item Type: Article
Título de Revista/Publicación: Journal of Display Technology
Date: January 2010
ISSN: 1551-319X
Volume: 7
Subjects:
Freetext Keywords: Liquid crystal on silicon (LCoS), pretilt angle, reflective display, twist angle, vertically aligned nematic (VAN).
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 and cell thickness are two extremely important parameters in predicting the behavior of vertically aligned negative nematic liquid crystal (LC) displays. The accurate estimation of pretilt angle and cell thickness is not a trivial task when these devices work in reflective mode, as in liquid crystal on silicon (LCOS) vertically aligned nematic (VAN) displays. Usual experimental setups are based on the proportionality between the retardation of the polarization components of the incident light and the product effective birefringence times thickness. However, any attempt to separate the two product variables is cancelled out by symmetry from reflection. This work shows a relatively simple method capable of separating both variables, allowing accurate, independent measurements of pretilt and thickness, as well as other configurations details, such as residual twist. A simulation model based on the properties of actual reflective displays has been developed. An experimental setup specifically designed for measuring LCOS VAN cells has been prepared. Initial comparisons between experimental measurements of intensity and theoretical results showed some discrepancies that could be explained assuming that the LC profile contains a residual twist from the manufacturing process. Including that twist in the model, an excellent agreement between theory and experiment has been achieved. Matching simulations and experimental results yield separate determinations of pretilt angle and thickness, and give good estimates for the residual twist angle.

More information

Item ID: 7230
DC Identifier: http://oa.upm.es/7230/
OAI Identifier: oai:oa.upm.es:7230
DOI: 10.1109/JDT.2010.2050857
Official URL: http://ieeexplore.ieee.org
Deposited by: Memoria Investigacion
Deposited on: 14 Jun 2011 10:59
Last Modified: 20 Apr 2016 16:25
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