Abstract: 1. An electron-discharge device comprising: an evacuated envelope; a cold electrode supported within said envelope; a thermionic filamentary cathode; and means including at least one spring member affixed to said cathode and supported from said envelope for normally supporting said cathode in tension in a position within said envelope spaced from said cold electrode and adapted to relax said tension in response to rapid acceleration of said envelope in a predetermined direction perpendicular to said filamentary cathode, the space between said normal position of said cathode and the inner wall of said envelope being substantially unobstructed in a direction opposite to said predetermined direction whereby said cathode is supported by said wall throughout substantially its entire length when subjected to said acceleration.

Abstract: An elasto-optic device for providing periodic lateral displacement in a radial tracking servo system for a video disc player. A transparent prism is vibrated in either a flexural or a second harmonic extensional mode by a thin piezoelectric ceramic platelet attached to a side of the prism and energized by an oscillatory signal. Vibration occurs at a natural mechanical resonant frequency of the prism, and a linear strain distribution is established in the prism at its intersection with the path of the optical beam used for reading the record track. The substantially linear strain distribution effects a corresponding localized periodic change in the index of refraction of the prism material to provide lateral optical beam deflection without the use of moving parts.

Abstract: Method and apparatus for enhancing the edges of video images displayed on a cathode ray tube. The scanning velocity of the cathode ray tube electron beam is modulated so as to counteract the blurring effect which occurs when a video amplitude transition causes an increase in beam current and a corresponding increase in the size of the electron beam spot at the screen of the cathode ray tube. When such a transition occurs, the beam is deflected in the direction of normal scan at a rate which corresponds to the rate of change in the size of the diameter of the spot so as to substantially arrest the spot edge, thereby causing a displayed video transition to have a better defined vertical edge. Horizontal edges of images are sharpened by auxiliary vertical deflection of the electron beam. Image edges are further improved by a video peaking scheme which eliminates the large spot size growth usually associated with large amplitude video transitions which have been peaked.

Abstract: An image screen structure for a monochrome or a color cathode-ray tube, in which the phosphor screen is interposed between a composite mesh and the conventional reflective metal backing layer. The composite mesh comprises a reflective grille and a non-reflective grille in registration with the reflective grille. The reflective grille faces the phosphor screen so that light generated by phosphor excitation behind the non-reflective grille finds egress by multiple reflections between the reflective grille and the metal backing layer. In a color cathode-ray tube such as a tri-color shadow-mask television picture tube, the non-reflective and reflective grilles may be non-coherent with the mosaic phosphor screen, thus avoiding the necessity of complicated and costly processing which has been employed in the manufacture of black-surround color picture tubes. A substantial improvement in brightness/contrast performance is obtained as compared with the best prior art monochrome and color cathode-ray tubes.

Abstract: An optical video disc playback system includes a feedback or servo arrangement through which radial beam tracking is maintained by controlled displacement of a mirror about a reference axis. The optical system which controls the reading beam is unique in that displacement of the mirror for tracking registration occasions no motion of the light pattern projected onto a photoreceptor employed for the development of a tracking correction signal and/or the program signal. By maintaining the photoreceptor at a distance from the record medium determined by the parameters of the final lens of the optical system, spurious error signals caused by record eccentricities are obviated.Various optical systems are disclosed, both for achieving variations in the overall physical dimensions of the system and for accommodating displacement of the reading beam for timing corrections in addition to beam displacement for radial tracking correction.

Abstract: An optical video disc has a multi-turn spiral track which stores a frequency modulated carrier modulated with program information in accordance with NTSC format. The recording is further characterized by the fact that the phase of the chroma subcarrier at the start of one convolution of the record track is substantially the same as that of the end of the convolution. In the playback process, the disc is rotated at a speed such that the chroma subcarrier is integrally related to the frequency of disc rotation.

Abstract: A video disc for an optical image reproducing system has a storage track formed of pits alternating with lands along a spiral path. The pit depth introduces a phase change of approximately .pi./2 radians between portions of a reading beam that impinge upon pits and portions that impinge upon lands adjacent the pits.