Cathode ray tube indexing structures

Abstract

A cathode ray tube gun structure for minor deflection of an electron beam and employing electrostatic beam deflecting electrodes ultimately controlled by a deflection signal at a low voltage level for minor deflection of the beam. The minor beam deflection electrodes may be positioned in the low beam potential focus region of the gun to provide for minor deflection of the beam. The electrodes may be enclosed in a cylindrical electrode, the latter being used for focusing the beam, or the cylindrical electrode may be omitted in which case focusing and deflection functions are provided by the minor beam deflection electrodes. The minor beam deflection electrodes may be positioned in a high beam potential region, in which case low voltage control is provided by capacitive coupling through the envelope of the tube. The deflection electrodes may also be employed as the conventional second grid structure in a cathode ray tube gun structure. A cathode ray tube gun structure having a grooved cathode surface in conjunction with grid structures containing rectangular apertures therein for the formation of a beam substantially rectangular in cross section having uniform beam density across the section. A screen for a cathode ray tube having a mosaic of elements, in which one or combinations of elements located between the glass face plate and a conventional backing layer are employed to enhance or inhibit secondary emission of electrons, as desired, for various regions of the mosaic. A screen for a cathode ray tube having a curvature defined by a radius R, the center of curvature of which is positioned at the center of magnetic deflection of the major beam deflection structure.