Thomson-csf

Sextant Avionique

Jean B Migozzi

Francois Grasdepot

Gerard Le Paih

Francoise Cheysson

A holographic filter for protection from radiation, notably laser radiation. At least one support is covered with at least two holograms. Each hologram is constituted by a stack of strata. The holograms are fixed to each other by an optical bonder associated with a selective absorbent material.

Holographic filter for protection from radiation, notably laser radiation

The infra-red diffractive optical lens will remedy chromatism faults and offer excellent compactness; in addition, it does not call for a cooling device. It comprises a first convergent lens made of a material corresponding to the operational infra-red band width considered and a second convergent lens formed by a surface hologram. This hologram is obtained by accurate machining of one of the diopters of the first convergent lens according to machining data optimized by digital calculations. The first lens is preferably made of zinc sulfide. This system can operate simultaneously in the 8 to 12 microns infra-red band and the 1.06 microns laser channel.

Infra-red diffractive optics applicable to a laser target designation

A display device with wide field and high optical efficiency is provided including an optical assembly having a spherical holographic mirror used on the axis and a semitransparent mirror. A generator of light images emits a radiation which strikes first of all the convex phase of the spherical mirror, passes through it, and is then reflected by the semitransparent mirror in the direction of the spherical mirror, which reflects it and finally sends it towards the observer. This optical collimation and combination assembly is included in a transparent medium formed by a glass plate with parallel faces and forming a stigmatic optical system at infinity, required for the correct reception of the radiation coming from the outside landscape.

Wide field high optical efficiency display device

In a device for optical-cable transport and combination of light images, the ends of an optical cable forming part of the device are coupled with lenses which are in turn associated with an optical system for dispersing radiation as a function of the wavelength in order to suppress any raster effect. This optical system is constituted at one end of the optical cable by a reflecting holographic mirror, the chromatic aberrations of which form the dispersion. At the other end of the cable, the optical system consists of a partially transparent holographic mirror for reflecting a first image to be transported and re-forming this image by suppressing the aberrations and combining said first image with a second image. The first image can be a synthetic image displayed on a CRT indicator and the second image can be the surrounding landscape in an application such as a helmet sight visor.

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Orsay, France

Jean B Migozzi