Nemoptic

Commissariat a L'energie Atomique

Matra

France Brevets

Alain Boissier

Philippe Martinot-Lagarde

Gilbert Boisde

Jacques Angele

Ivan N Dozov

François Leblanc

Bertrand Pecout

Jean-Francois Legay

Olivier Duhem

Alain Glatigny

Ivan Dozov

The present invention relates to a display device comprising a bistable nematic liquid-crystal matrix screen with anchoring breaking, characterized in that it comprises:

Bistable nematic liquid crystal display device and method for controlling such a device

The invention relates to a bistable nematic liquid-crystal device comprising: alignment means, which orient the liquid crystal, means designed to apply electrical signals which allow switching, by breaking the anchoring on at least one of the two substrates, between two distinct textures, and means designed to promote the establishment of that one of the said textures giving the off state in the liquid crystal covering the inter-electrode spaces.

Bistable nematic liquid crystal display device with improved optical mask, having textures differing by about 180&#xb0; twist, and off state in the liquid crystal covering the inter-electrode spaces

The present invention provides an electro-optical device, characterized in that it comprises two plane optical substrates () each having at least one optical waveguide (), and a nematic liquid crystal () inserted between them, in which the liquid crystal () is split into two separate active zones () serving to control coupling/decoupling of a respective one of the TE and TM polarizations of a light signal injected into the waveguides ().

Liquid crystal-based electro-optical device forming, in particular, a switch

An identity document has graphical information printed on a support and including uncoded alphanumerical information which is specific to a holder of the document or to the document. The surface of the support is broken down into a network of macropixels each having a predetermined average light absorption level. Each of the micropixels in turn consists of a dot pattern matrix of micropixels each having a light absorption level selected among at least two predetermined levels and distributed for the average absorption of each of the macropixels to be said predetermined average light absorption level and for constituting a screen which reproduces on a microscopic scale part at least of the uncoded specific information.

Identity document difficult to falsify and a process for manufacturing

Photometric cell of the type comprising two juxtaposed spherical half-mirrors M.sub.1 and M.sub.2 and a third spherical mirror M facing mirrors M.sub.1 and M.sub.2, the three mirrors having the same radius of curvature, while mirrors M.sub.1 and M.sub.2 have their centers of curvature C.sub.1 and C.sub.2 located on mirror M and slightly displaced with respect to one another and mirror M has its center of curvature C between the two mirrors M.sub.1 and M.sub.2, optical means being provided for introducing a measuring light beam into the cell through an entrance diaphragm E and for extracting it therefrom after multiple reflections on said mirrors through an exit diaphragm S, wherein the mirror M is truncated perpendicular to a line joining the centers C.sub.1 and C.sub.2, the truncated portion of the mirror being replaced by an optical system L operating by transmission, the entrance diaphragm E and exit diaphragm S being positioned level with said optical system L on a line perpendicular to lines C.sub.1 -C.sub.2, and wherein it also comprises a third half-mirror M.sub.3, the optical system L being such that the half-mirrors M.sub.1 and M.sub.2 are conjugate to one another, while the third half-mirror M.sub.3 has a center of curvature C.sub.3 located on the line joining the two diaphragms E and S conjugate to one another by the mirrors and the optical system L.

Photometric cell

Photometer of the type comprising two facing mirrors, means for introducing a light beam between said mirrors, extraction means for said light beam after multiple reflections on the mirrors and means for introducing a fluid to be measured between these mirrors, wherein the two mirrors are concave mirrors, whose centers of curvature are slightly staggered relative to one another and wherein it comprises a field optics by transmission disposed in the vicinity of the centers and which optically conjugates the mirrors, the light beam introduction means comprising a first optical system having an exit pupil in the vicinity of the field optics, the extraction means of the light beam comprising a second optical system having an entrance pupil in the vicinity of the field optics, said entrance and exit pupils being optically conjugated by the action of the multiple reflections on the mirrors. Particular applications of the photometer are to the measurement of the turbidity of nuclear reactor and river waters or to the detection of pollutants in liquids or gases.

Growing community of inventors

Marly le roi, France

Alain Boissier