Thomson-csf

Thomson-brandt

Thales

Sextant Avionique

Jean-Claude Lehureau

Claude Bricot

Henriette Magna

Jean-Pierre Huignard

Brigitte Loiseaux

Bruno Mourey

Jean Cornet

Michel Thirouard

Sophie Neubert

Claude Puech

Jean-Claude Dubois

Joseph Colineau

Paul-Louis Meunier

Francois Le Carvennec

Pierre Oprandi

Cecile Joubert

Patrick Feneyrou

C&eacute;cile Joubert

Francois LeCarvennec

Jean Pierre Huignard

Jean-Pierre Schlotterbeck

Daniel Dolfi

Daniel Kaplan

Laurent Bignolles

Jean-Marc Coutellier

Bernard Chaumet

Bertrand Morbieu

Dominique Leterme

Roland Malissin

Gerald Roullet

Jean-Pierre Lacotte

Francois Lange

Louis Arquie

Jean-Pierre Le Merer

Pierre-Olivier Lefort

Laurent Georges

Nicolas Millet

Roger Rascle

Christian Maillot

Jean-Charles Renaud

Michele Labeyrie

Pascal Joffre

Francedillaois-Xavier Pirot

Fran&ccedil;ois-Xavier Pirot

Frederic De Lauzun

Hervé Barny

Jean-Paul Peltier

Guy Bourdon

Philippe Bousquet

The general field of the invention is that of optical devices designed for measuring anemometer parameters such as speed and temperature, the device being mounted on an aircraft and comprising an optical emission module illuminating the outside air, an optical reception module capable of receiving the light scattered by the air molecules, optical means forming a reference path and computing means connected to the reception module. The optical reception module comprises optical mixing means for mixing a portion of the beam originating from the reference path and a portion of the scattered light beam. The optical emission and reception means are arranged so that the reception device collects the light originating from the Brillouin-Mandel'shtam scattering.

Optical device for measuring anemometer parameters

The invention relates to a method of protecting aircraft in flight against clear air turbulence (CAT). Consider an aircraft occupying a position P and moving horizontally at a speed V, a plane Pbeing the horizontal plane passing through P. According to the invention, the method includes performing at least one pair of evaluations of air temperature T, Tat two points B, C which have positions that are symmetrical relative to the plane P. At least one pair of horizontal air speed evaluations are performed VH, VHat the two points B, C; An air temperature gradient is determined; A horizontal air speed gradient is determined; An index signifying a presence of CAT is determined; The preceding steps are repeated; A trend is analyzed over time of the index.

Method and device for protecting an aircraft against clear air turbulence

The invention relates to a radial slaving method and to a reproduction device implementing it for optical discs. In an optical head of a conventional reproduction device using a four-quadrant detector with four photodiode is distributed on either side of a direction parallel to the axis of the track, the individual signals of the photodiodes (dto d) are combined in order to obtain read signals along the two diagonals (diag, diag) by subtraction (). A phase comparison signal circuit () makes it possible to construct a radial error signal (Sr) by measuring the phase shift of the diagonal read signals. The invention applies in particular to phase discs with slightly phase-shifting marks.

Radial control method for a device for reproducing information of an optical disk, and reproduction device for carrying out said method

The field of the invention is that of devices for detecting non-metallic objects concealed on human subjects. These devices are more particularly dedicated to the surveillance and protection of reserved access areas, such as airport areas. The device according to the invention comprises a portable detector comprising a transmitter and a receiver of microwave frequency signals disposed in an enclosure of chaotic geometry including a plurality of measurement holes. The microwave frequency signal measured by this detector depends on the nature of the objects disposed under the holes. A processing device linked to this detector is used to correlate the measured signals with prerecorded signals. When the correlation exceeds a certain threshold corresponding to the presence of suspect objects, an alarm is generated.

Detector of objects by microwave frequency echo analysis

The present invention relates to a fiber-optic gyrometer including a Sagnac interferometer using two light waves propagating in opposite directions in a interferometer loop including a photodetector which delivers an electrical signal Ud representing the light intensity of the interference between the two waves, and for optically phase-shifting the waves controlled by a square-wave modulation signal Um suitable for controlling an optical phase variation at a frequency FO substantially equal to 1/(2), where tis the propagation time of a wave through the guide. The photodetector is connected to at least a first sampling circuit and a second sampling circuit which are controlled in phase opposition by a clock. The gyrometer includes a means for inverting the phase of the clock at a frequency f, which is very much less than the frequency FO.

Nonreciprocal phase shift fiber-optic gyrometer

The invention concerns a recording medium for optically readable data of the multilayer type, a method for making same and an optical system for reproducing said data for reading the medium. The medium (Sb) comprises a stack of layers (Cto CN) whereof the interfaces constitute planes (Pto PN) bearing slightly phase-shifting information elements. Said planes generate a relatively significant disturbance of the transmitted beam while diffracting only a very small part of the light passing through them. The reading beam (FI) is focused on the bearing plane and reading is performed by transmission. The disturbances caused by the neighboring defocused layers are eliminated by far field detection of only the low spatial frequencies in the transmitted beam. The invention is particularly useful for very high capacity data optical storage.

Medium for recording optically readable data, method for making same and optical system reproducing said data

The invention relates to the field of devices for measuring a nonreciprocal effect and especially to the field of fiber-optic gyrometers. Disclosed a device for measuring a nonreciprocal effect comprising a light source, a monomode spatial filter, a Sagnac ring having two branches, a light splitter, and a light detector. The splitter is a polarization splitter. The filter is nonpolarizing. The detector includes a system for analyzing the polarization state. The light splitter devides the light over branches of the ring. The invention can be applied to other devices for measuring a nonreciprocal effect, especially fiber-optic magnetometers.

Device for measuring a non-reciprocal effect, in particular fiber-optic gyro

Unlike customary vibrating mass gyros which operate by exciting a first fundamental mode of vibration of the vibrating mass and by detecting the effect of the Coriolis force on a second fundamental mode of vibration of the vibrating mass orthogonal to the first mode, this gyro operates by giving its suspended mass a circular motion alternately in the forward and reverse directions and by deducing the gyrometric effect from the difference between the apparent frequencies of the circular motion of the suspended mass in one direction and in the other. This allows a considerable reduction in the drafting of the heading measurement obtained with this type of gyro.

Vibrating mass gyro

A quantum encryption device comprises a transmitter and a receiver between which an encrypted piece of information is transmitted. The transmitter comprises at least means to send a first packet of photons and an information photon to the receiver, the appearance of the information photon following the packet being lagged by a period of time &tgr; according to a law of probability. The transmitter also comprises means for the encoding of the information photon. The receiver comprises at least means for the encoding of a second packet of photons coming from the first packet and substantially lagged by the period of time &tgr; with respect to this packet, and interference means to make an information photon interfere with the second packet of photons. These interference means provide a packet of photons to create a quantity of photons substantially equal to &plusmn;2 times the variance of the noise due to the second packet. The invention can be applied to the industrial-scale making of encryption systems.

Quantum encryption device

An anti-piracy recording disk. The disk includes a main recording track which has interruptions or changes of turn. This gives rise to non-sequential reading and therefore to information which is difficult to access. The copying of such a disk by conventional means is very difficult making it possible to easily detect counterfeits or to render any copy unusable.

Anti-chipping recording disc, reading method and recording head

A polarization splitter which includes a splitting medium lying between two transparent elements of defined indices. The splitting medium includes a periodic structure of layers of materials of different indices and having a period which is small compared with the wavelength of an incident beam so as to form a uniaxial birefringent medium of optical axis perpendicular to the plane of the periodic structure. The two transparent elements are made of a material of index approximately equal to the ordinary index (n ) of the periodic structure.

Polarization beam splitter

A holographic projection screen for large screen projection and back projection with a liquid crystal projector. The screen includes at least one layer made of a photosensitive material in which at least one index grating may be recorded by an interference of an optical recording wave with an optical object wave. The thickness of the layer is equal to or greater than n,&Lgr;,/2&pgr;, where n,is the average index of the photosensitive material, &Lgr; is the average spacing of the index grating and &lgr; is the recording wavelength.

Holographic projection screen and method of production

Display panel with compensation by holographic birefringent films

An illumination device comprises a light source coupled to a waveguide. the waveguide comprises a diffracting element capable of diffracting emergent light rays coming from the source, in a direction substantially perpendicular to the surface of the waveguide. A device of this kind is particularly well-suited to transmissive display screens of the liquid crystal display screen type. It can generate a highly collimated, polarized light.

Illumination device and application thereof to the illumination of a

A magnetic head has two poles separated by a gap and at least one saturable element. The saturable element joins the poles and is outside the gap and parallel to the gap. The head may be in the form of a matrix device having a number of poles mounted over a similar number of pads in the substrate. The saturable element may link two poles of the head by means of a pole of another magnetic head.

Magnetic head with saturable element between the poles outside of the gap

Growing community of inventors

Sainte Genevieve des Bois, France

Jean-Claude Lehureau