Abstract: In an interactive display device and method, a video projector projects an image on a screen. An optical pointer includes a mouse click signal input button and a light source emitting a light beam for pointing to the screen to form a light mark. A detection camera acquires an image from the screen and detects an image from the light mark. A processing system calculates the position of the light mark in the detected image. The optical pointer includes: a contact or proximity detector capable of detecting a contact between one end of the optical pointer and the screen and generating a light mark presence signal; and moreover a radio transmitter capable of transmitting a light mark presence signal to a processing system. The treatment system compared the respective signals for detecting a light mark and light mark presence to deduce therefrom a validation signal for the light mark.

Abstract: The present invention relates to a display device comprising a bistable nematic liquid-crystal matrix screen with anchoring breaking, characterized in that it comprises: components (40) capable of switching between an off state and an on state, these components being placed respectively between a drive electrode (47) associated with each pixel and a display state control link (45); and means capable of applying, to the input of each aforementioned component (40), via the state control link (45), input signals comprising at least two phases separated by a controlled time interval, namely a first phase during which the input signal has an amplitude sufficient to permit breaking of the anchoring of the liquid crystal on the associated pixel, then a second phase during which the amplitude of the input signal is controlled in order to select one of the two bistable states of the liquid crystal, the time interval between the two phases being adapted in order to break the anchoring of the liquid crystal on the sa

Abstract: 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.

Abstract: The present invention relates to a display device comprising a bistable nematic liquid-crystal matrix screen with anchoring breaking, characterized in that it comprises: components (40) capable of switching between an off state and an on state, these components being placed respectively between a drive electrode (47) associated with each pixel and a display state control link (45); and means capable of applying, to the input of each aforementioned component (40), via the state control link (45), input signals comprising at least two phases separated by a controlled time interval, namely a first phase during which the input signal has an amplitude sufficient to permit breaking of the anchoring of the liquid crystal on the associated pixel, then a second phase during which the amplitude of the input signal is controlled in order to select one of the two bistable states of the liquid crystal, the time interval between the two phases being adapted in order to break the anchoring of the liquid crystal on the s

Abstract: The present invention provides an electro-optical device, characterized in that it comprises two plane optical substrates (100) each having at least one optical waveguide (110), and a nematic liquid crystal (200) inserted between them, in which the liquid crystal (200) is split into two separate active zones (210, 220) serving to control coupling/decoupling of a respective one of the TE and TM polarizations of a light signal injected into the waveguides (110).

Abstract: 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.

Abstract: The present invention provides an electro-optical device, characterized in that it comprises two plane optical substrates (100) each having at least one optical waveguide (110), and a nematic liquid crystal (200) inserted between them, in which the liquid crystal (200) is split into two separate active zones (210, 220) serving to control coupling/decoupling of a respective one of the TE and TM polarizations of a light signal injected into the waveguides (110).

Abstract: 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.

Abstract: 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.

Abstract: 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.