Art Tech Gigadisc 'atg'

Alcatel Thomson Gigadisc

Art Tech Gigadisc

Daniel Bec

Michel Collomby

Jean-Louis Gerard

Michele LeBlanc

Jean-Pierre Le Merer

Jean-Pierre Le Merrer

The present invention relates to various improvements to a device for access and tracking to a track carried by an information medium, the information being readable and/or recordable optically by a focused radiation, this track forming, on the medium, regularly-spaced or variably spaced revolutions, the revolutions forming a spiral or having the form of concentric circular elements, the device comprising an optical head (1) with optical axis A orthogonal to the plane of the medium, a fixed magnetic circuit comprising at least one core (7) secant to the set of revolutions of the track, in the gap of which two coils (14, 15) move permitting respectively track access and radial tracking to be achieved, as well as focusing of the radiation onto the track, the optical head and the two coils being fixed rigidly to one another in such a way as to form a single compact mobile unit. According to one improvement, the two coils (14, 15) are set in a symmetric arrangement, the desired movement being obtained by addition of forces (F, F') induced by the currents flowing in the coils.

Access and tracking device for an optical disc

Forward/backward counting device

Control device for servocontrolling an object to a given position

A mobile optically-readable data medium, arranged in the form of a set of tracks having a sampled type format, each track having pre-engraved zones, known as pre-format zones, and zones reserved for user data, access to said tracks being obtained using pre-engraved marks, known as access marks, representing on each track at least one part of the address of the latter. This medium has no specific radial tracking marks. A reading device for information engraved on the surface of a medium such as that described above; this device performs the radial tracking using information read from the access marks. The invention applies to digital optical disks.

Optically-readable data medium and reading device for such a medium

A device for accessing and following tracks on a surface of mobile media on which data is optically readable and writable by a laser beam. The device includes at least one optical head made of a rigid carriage which enables a laser beam (F) to access the track. A lens is rigidly linked to the rigid carriage (3) and focuses the laser beam on the surface of the mobile data medium. A return mirror is rigidly linked to the rigid carriage to direct the laser beam towards the lens. At least one motor coil allows movements of the carriage to focus the laser beam. A mirror which is not fixed to the optical head allows the laser beam to be directed towards the optical head, and a motor coil allows the mirror to pivot. Also means are provided for detecting and correcting any decentering of the beam in relation to the axis perpendicular to the plane of a pupil of the lens and passing through its center. The correction is applied along a direction defined by the axis, perpendicular to said axis and contained in the plane perpendicular to the plane of the pupil, and the center of the return mirror, and the center of the mirror which allows the laser beam to be directed towards the optical head. The device is applicable to readers and recorders of mobile media containing optically readable or recordable data.

Separation type mono block optical head with tracking control achieved

Disclosed is a device for access to and follower control of a track of an optical disk. This device has an optical head with an axis orthogonal to the plane of the disk, at least one fixed magnetic circuit comprising a core that is secant with all the turns of the track, the gap of which forms a plane that is substantially perpendicular to the support, a first motor device allowing for the access to and radial tracking of the track formed by at least one first coil mounted so that it moves on the core of the magnetic circuit and a second motor device that enables the focusing of the radiation on the track consisting of a second coil cooperating with a magnetic circuit. The optical head, the coil of the first motor device and the coil of the second motor device are rigidly fixed to one another so as to form a single compact moving element that moves in the gaps of the magnetic circuits. The disclosed device can be applied to digital optical disks.

Access and follower control device for optical disk

Data is stored on a prewritten optical data storage medium along a track made up of adjacent elements. A scanning light spot focussed on the medium has to be able to access any element to write, read or modify data there. Prewritten patterns on the medium define a radial graduation scale that is analysed by an optical scaning device using a sampling technique to determine the absolute position of the scanning light spot relative to the track elements, the only material representation of which may be discrete prewritten elements. The technology is particularly applicable to very high density optical memories using a prewritten disk written by thermo-optical interaction with an intensity modulated laser beam.

Prewritten data storage medium and optical scanning device therefor

Data is stored on a prewritten optical data storage medium along a track made up of adjacent elements. A scanning light spot focussed on the medium has to be able to access any element to write, read or modify data there. Prewritten patterns on the medium define a radial graduation scale that is analyzed by an optical scanning device using a sampling technique to determine the absolute position of the scanning light spot relative to the track elements, the only material representation of which may be discrete prewritten elements. The technology is particularly applicable to very high density optical memories using a prewritten disk written by thermo-optical interaction with an intensity modulated laser beam.

Growing community of inventors

Villeneuve Tolosane, France

Daniel Bec