Dichroic dyes, electronic dyes, liquid crystalline dyes

Could Dichroic Dyes enable low cost heads up displays for low end vehicles?

VITSWEL SMART WINDOW

Methyl Orange Dye

Disperse Orange 1 Dye

Solvent Yellow 124 Dye

Cholesterinisch (Cholesteric) Orientation

Nematic Orientation

Twisted Nematic LCD Schematic

Some dichroic displays do not utilize polarizers.

During the last century, dichroic dyes had been used as electric field responsive colorants for rugged avionics and armored vehicle electronic displays(2). In general, dichroic dye displays had more predictable performance than twisted nematic liquid crystal displays or plasma displays, until technological advances in nematic displays surpassed the performance of dichroic dyes.

These displays were used in early Boeing 757 and 767 models, and the displays were manufactured by LITTON, STANLEY ELECTRIC, RACAL, AEG & Crystalloid, amongst others(2).

In the Sovient Union, dye research was extensively performed by Niopik http://www.niopik.ru/. Currently dichroic displays for avionics is manufactured in the USA by Transicoil and Polytronix. Dichroic displays are also manufactured by AlphaMicron , amongst others.

Many dyes exhibit dichroism(1). Some of these dyes are soluble in commercial liquid crystals(4).

Dyes which are effective for use in liquid crystal displays :

Azomethine

Indigoid and Thioindigoid

Merocyanine

Azulenes

Quinophthalonic

Perylene

Phthaloperine

Triphenodioxazines

Quinoxalines

Triazine

Tertrazine

Azo

Anthraquinone

After considerable research, scientists and engineers have identified dyes have proven suitable for use for liquid crystal displays(2). The dyes need adequate lightfastness, suitable wavelength bands, and sufficient order parameter in a liquid crystal host to function as display ingredients.

Obtaining dyes with sufficient order parameter in the liquid crystal host has been one of the primary challenges to the adoption of dichroic dyes by industry(2). Although some dyes exhibit some dichroic qualities, most dyes do not have sufficient dichroic order parameter to function as display ingredients.

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Wikipedia