Technology for electronically varying helmet visor tint

Bahman Taheri; Peter Palffy-Muhoray; Tamas Kosa; David L. Post

doi:10.1117/12.389139

23 June 2000 Technology for electronically varying helmet visor tint

Bahman Taheri, Peter Palffy-Muhoray, Tamas Kosa, David L. Post

Proceedings Volume 4021, Helmet- and Head-Mounted Displays V; (2000) https://doi.org/10.1117/12.389139
Event: AeroSense 2000, 2000, Orlando, FL, United States

Abstract

Increasing interest in helmet-mounted displays (HMDs) has fueled research in variable transmittance visors (VTVs) because a VTV can reduce glare and increase HMD contrast in bright lighting conditions. The ideal VTV will be an electrically controllable light valve that allows the pilot to adjust visor transmittance (tint) to the level appropriate to the ambient lighting conditions. Liquid- crystal based devices can provide an efficient method for accomplishing this. Because flight helmets utilize polycarbonate visors, VTVs must be implemented on complex curved, plastic substrates. Liquid crystal devices, however, are typically implemented on flat glass substrates. We present a novel system, Variable Attenuation Liquid Crystal Device (VALiD), which can be utilized for this application. VALiD is a dichroic dye and liquid crystal based guest-host system. Our specific configuration allows for a fast system that fails to the clear state. Furthermore, the degree of polarization dependence can be tailored for use in different applications. VALiD has been implemented on thin, flexible, flat plastic substrates. Recently, this has been extended to doubly curved polycarbonate substrates and a prototype has been fabricated. In this paper we present the characteristics of this technology.

Citation Download Citation

Bahman Taheri, Peter Palffy-Muhoray, Tamas Kosa, and David L. Post "Technology for electronically varying helmet visor tint", Proc. SPIE 4021, Helmet- and Head-Mounted Displays V, (23 June 2000); https://doi.org/10.1117/12.389139

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