Liquid crystal devices

Details Liquid crystal devices Liquid crystal devices

1977-02-14

1978-04-18

Corbin, John K.

G02F 113

Patent

active

040848841

ABSTRACT:
It has been found that twisted nematic liquid display devices can have a patchy appearance as a result of two problems concerned with degeneracy of the orientation of the molecules in the "on" and "off" states respectively. In the present invention these two problems are solved together by using as the liquid crystal material a naturally optically active material having a molecular helical pitch not less than twice the spacing between the substrates of the device cell, and
(1) by treating and later arranging the surfaces of the substrates so that the molecules in the cell liquid crystal layer all lie generally obliquely to the plane of the substrates in the "off" state, or
(2) by treating and later arranging the surfaces of the substrates so that the liquid crystal molecules adjacent to one substrate lie in the plane of the substrate but the molecules adjacent to the other substrate lie oblique to that substrate whereby the molecules in the interior of the layer lie slightly oblique to both substrates.
In accordance with (1), the substrates may be rubbed in the conventional way and two unit vectors defined by the rubbing directions may be specially selected having regard to the natural molecular helix of the liquid crystal molecules to give the desired molecular arrangement in the cell.
In the embodiment (2), both substrates may be deposited with a dielectric coating evaporated with an angle of incidence .theta. in the range 15.degree. .ltoreq..theta..ltoreq.45.degree. and one of the substrates may be rubbed before arranging the respective projections of the evaporation direction on the substrates to be perpendicular to one another.

REFERENCES:
sussman A, "Electro-optic Liquid Crystal Devices; Principles and Applications", IEEE Trans., vol. PHP-8, No. 4, Dec. 1972, pp. 24-37.
Guyon, E. et al., "On Different Boundry Conditions of Nematic Films on Obliquely Evaporated Plates", Lett. in App. Eng. Sciences, vol. 1, pp. 19-24, 1973.
Gray G. W., Harrison K. J., Nash J. A., "New Family of Nematic Liquid Crystals for Display", Elec. Lett., vol. 9, No. 6, Mar. 22, 1973, pp. 130-131.

Affiliated with

Also associated with

Rating

Liquid crystal devices does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Liquid crystal devices, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Liquid crystal devices will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2144909