Thomson-csf

Christian Maillot

Jean-Pierre Huignard

Jean-Claude Lehureau

Claude Puech

Francois Micheron

Paul-Louis Meunier

Jean-Claude Lhureau

Jean L Ayrai

Marc Dorel

A matrix type magnetic recording/reading head made in integrated fashion, including an electrically non-conductive ceramic substrate having a first main face and a second main face, each provided with connection areas. The two areas of the two faces are interconnected in sets of two by internal connection elements. A layer with high magnetic permeability is deposited on the first face of the substrate. The substrate bears a first series of row conductors and a second series of column conductors intersecting the row conductors, each conductor being connected to a connection area of the first face. Pairs of magnetic poles are located substantially at the intersection of the row conductor and column conductors, the poles of each pair separated by a gap space and being magnetically coupled to the layer with high magnetic permeability in two opposite zones defined by the intersection of a row conductor and a column conductor.

Method of manufacturing a recording/reading matrix magnetic head

Disclosed is a system for the recording of data on optic disks. Presently used optic disks, which can be read with lasers working in wavelengths of the visible region (between 0.5 and 0.8 microns), have a maximum surface storage density of the order of one data bit per elementary zone having an area of about one square micrometer. Beyond this limit, the diffraction does not allow the neighboring zones to be distinguished. A means is proposed to considerably increase the storage capacities: in an elementary zone of a layer, an information bit is written not in the form of a point of absorption of a laser light but in the form of a diffraction grating with a determined pitch. Several diffraction gratings, having pitches different from one another, may be superimposed at the same position, enabling the recording, in one and the same zone, of several information bits. The diffraction gratings are made by a periodic local variation of the optic index of the layer. They are made by a high energy laser beam, out of a material with an index that may vary as a function of this energy. The reading is done by a frequency tunable laser that enables the detection, for different frequencies, of the presence or absence of diffraction gratings.

Optical storage method and device for storing and reading digital

The disclosure relates to a magneto-optical reading head. A magneto-optical head comprises an optically active part which is a very thin magnetic layer that causes the rotation of the plane of polarization of the light as a function of its magnetic polarization which is itself linked to the magnetic polarization of the magnetic tape that bears the information elements to be read and moves past the thin layer. Instead of using a focusing optical device to illuminate the optically active part, it is provided that the head will comprise an optical guide which ends directly before the active part and is such that the plane of incidence of the light rays on the optically active part is perpendicular to the general direction of elongation of a gap region before which the magnetic tape passes. There is also provision, preferably, for a photosensitive sensor (linear array) that is integrated into the head so as to be at a distance of less than a few micrometers from the optically active part on the path of the beam modulated by this part. FIG. 5.

Magneto-optical reading head

A memory display system is provided including:

Growing community of inventors

Courbevoie, France

Christian Maillot