Themomagnetic transducing system

Claim 2

A transducer and storage system comprising: a first, flat magnetizable storage carrier having temperature dependent coercivity, and relatively high room temperature coercivity; a second, flat magnetizable layer in surface-to-surface contact with the first carrier and having relatively low room temperature coercivity and relatively high remanence; first means including a cathode-ray tube, having said first flat carrier as screen and including an electron gun, the second carrier facing away from the electron gun for providing radiant energy to said carrier to impart, upon particular areas of said carrier, predetermined quantities of thermal energy for reducing the coercivity in said particular areas; second means for providing to the carrier magnetization and including means for selectively providing a magnetic field in a first direction in the first carrier at a field strength in excess of room temperature coercivity, and in a second direction opposite to the first direction in the first carrier at field strength below room temperature coercivity so that the magnetization in the particular areas, after exposure to the radiation, has direction different from the direction of magnetization in areas juxtaposed to the particular areas; third means for controlling the operation of individual ones of the first and second means in accordance with the information to be stored to control the intensity of the radiant energy from the first means or the magnetization from the second means; a prism having its base disposed on the second carrier; fourth means for directing a beam of polarized light toward the prism base for obtaining total reflection in the interface of prism base and second carrier to obtain a change in the polarization of light in accordance with the interaction of the polarized light with magnetic field provided by the magnetization of the carrier; and analyzing means disposed in the path of light as reflected by tHe prism base to be responsive to the rotations in the polarized light for converting said changes in the polarized light into an illumination contrast.

Claim 3

A scan converter using a medium for temporary storage, the medium having a relatively low Curie point and temperature dependent remanence and coercivity and having properties of becoming paramagnetic when subjected to heat beyond a particular temperature and having remanence properties of retaining increasing amounts of magnetization upon becoming subsequently cooled below the particular temperature, comprising: means for providing a relatively strong uniform magnetization to the medium, to magnetize the medium at saturation in a first direction; first means for directing a beam of radiant energy towards said medium for absorption therein, said first means including means for providing relative displacement between said beam and said medium in a lateral direction and including means for providing relative movement between the medium and the beam in a longitudinal direction transverse to the lateral direction to inscribe a sequence of parallel tracks on the medium transverse to said direction of magnetization; second means for modulating the intensity of the beam in accordance with an input signal to provide a variable width of said tracks and having sharply delineated boundaries within which the carrier has particularly reduced coercivity, the width varying in accordance with such modulations; third means for magnetizing the medium to provide a magnetization of the medium within the boundaries of the tracks having direction opposite to the remaining magnetization of the medium in the first direction and between the tracks; fourth means for directing a collimated beam of linearly polarized light toward said medium; a prism having a base disposed in relation to the medium, so that upon total reflection of the polarized beam, on the base the beams interact with the differently directed magnetic field respectively provided by the magnetized medium in and in between the tracks to provide differently oriented rotation of the polarized light in accordance with such interaction; analyzing means for receiving said reflected beam and producing an illumination field having contrasts at different positions in the tracks in accordance with the rotation of the polarized light; and fifth means for scanning said illuminating field to produce an output signal in accordance with the contrasts in the illumination at the different positions.

Claim 5

A device as in claim 5, including sixth means for uniformly heating the carrier to a temperature well below said particular temperature, without substantially affecting the magnetization in the carrier as provided by the first means, the sixth means disposed so that the portion of the carrier interacting with the beam has temperature above room temperature.

Claim 6

A transducing system as set forth in claim 5, comprising: means (a) for directing a beam of collimated linear polarized light towards said carrier for interaction with the spatially variable magnetization recorded on the carrier; and means (b) responsive to a variable degree of rotation of the polarized light resulting from interaction of the spatially variable magnetization of said carrier with the polarized light to indicate at each instant the spatially variable magnetization recorded on the carrier.