Thomson-csf

Lydie Thirant

Michel Hareng

Serge Le Berre

Annie Beguin

Jean Claude Dubois

Bruno Mourey

Pierre Le Barny

Jean P Billard

A screen of a visual display device combining a thermal effect and an electrical effect for controlling an electrooptical material is obtained by replacing the glass plate of the screen facing the heating strips contributing to the thermal effect by a plate with better thermal insulation characteristics than glass, in order to reduce the control power.

Screen of a display device using a mixed thermal and electrical effect

The invention relates to an organic compound obtained by synthesis from 3,5-dihydroxybenzoic acid. The compound according to the invention is in accordance with the following general formula: ##STR1## in which R stands for an organic group of the alkyl, alkoxy or alkyl carboxylate type having 1 to 15 carbon atoms and in which X designates a nitrile or halogene group.

Diphenyl benzoates and its use as a dopant for smectic liquid crystals

The invention relates to matrix access display devices using a mixed thermal and electric effect and provides a display device with mixed thermal-electric drive using a smectic liquid crystal deprived of a nematic phase by addition of appropriate dopes.

Smectic liquid crystal display device without a nematic phase

The invention describes a liquid crystal display device with storage and local erasure, utilizing a thermo-optical effect to write an image under the form of scattering points in a layer of a material exhibiting a smectic mesophase. The energy necessary for the writing of the image is considerable reduced by effecting the change from the transparent to the scattering state without leaving the smectic mesophase. This result is obtained by treating the walls enclosing the layer so as to impart to smectic material a first given uniform orientation and imposing it, by the action of an electric field, a second uniform orientation perpendicular to the first; under local heating to a temperature in the neighborhood of the smectic-nematic transition temperature, the material tends to take up again the orientation imparted by the walls, thus locally generating a scattering structure.

Growing community of inventors

Paris, France

Lydie Thirant