GB927831A - Improvements in or relating to microwave process and apparatus - Google Patents

Abstract

927,831. Recording &c. by micro-waves. LITTON INDUSTRIES Inc. Sept. 19, 1961 [Sept.29, 1960; Dec. 5, 1960 (2)], No. 33537/61. Class 40 (2). A recording process comprises subjecting a microwave sensitive material to a high-intensity static magnetic field to tune the material into energy reactive relationship with the frequency of a radiant electromagnetic beam. A tape base record member 11 has deposited thereon a layer of wax supporting a plurality of aligned crystals 12 of a semiconducting material capable of providing free orbiting electrons or sub-atomic particles. The tape is irradiated with X- rays, neutrons, high energy electrons or the like 13, Fig. 3, such that electrons from the crystals are freed from the atoms and rotate about its atoms in fixed parallel orbital planes or spin axes 17, the angle of which is determined by the incident radiation. The tape is then subjected to a static magnetic field 18, Fig. 4, the intensity of which controls the spin rate and is substantially linear over a given range of field strength. The record member is then exposed to a polarized beam of a radio-frequency signal to be recorded introduced by a waveguide 19, Fig. 5, and directed such that its H component is transverse to the static field, whereby the orbiting particles absorb energy and produce heat to soften the wax so that the crystals assume disoriented positions, Fig. 6. After exposure to the radio beam, the wax layer hardens and maintains the displaced crystals in positions which permanently record or store the energy from the radio beam. For playback of the recorded information, the tape is again subjected to a static field and scanned by a weak radio beam from a waveguide 19a, Fig. 7. A suitable detector waveguide 20 is located on the other face. Areas which have not been affected by the recording absorb the energy from the weak beam, but the recorded areas produce little or no absorbtion and allow the beam to pass through the medium and be detected by the detector waveguide 20. In a second embodiment (Figs. 9-14 (not shown)), the coating is of material which changes its colour under the influence of heat to produce a more permanent record which is played back optically. Specification 702,000 is referred to.