Scan velocity modulation apparatus
AssigneeVideocolor
InventorsBernard Priere, Jean-Pierre Fourche, Alain Dossot
Life of this patent
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Abstract
A scan velocity modulation (SVM) coil arrangement for a cathode ray tube has SVM coils arranged on a rear portion of the main horizontal deflection coils. The main horizontal coils are of the saddle type and have flat end turns at the rear of the deflection coil, lying along the surface of the picture tube. The SVM coil is placed over the flat rear end turns forward of the static convergence magnets and forward of ferromagnetic materials associated with the electron gun. The sensitivity of the SVM coil is increased to the point that the coil can be efficiently driven in a progressively scanned raster display, at twice the horizontal rate of an interleaved raster display.
Claims15
A scan velocity modulation apparatus for a cathode ray tube, the cathode ray tube including an electron gun adjacent a rear end of the tube, for emitting an electron beam along a beam path from the electron gun through a funnel of the tube to a screen at a front of the tube, the apparatus comprising:
- a static convergence magnet assembly disposed over the electron beam path;
- a primary deflection yoke including a vertical deflection winding for vertical deflection of the beam and a horizontal deflection coil for horizontal deflection of the beam, the horizontal deflection coil having end turns at a rear end, disposed substantially adjacent to the static convergence magnet;
- and
- a scan velocity modulation coil for modifying said horizontal deflection of the electron beam, the scan velocity modulation coil located along the longitudinal axis of the tube adjacent the horizontal deflection coil, with one of the two coils at least partly overlapping the other coil.
A scan velocity modulation apparatus for a cathode ray tube, the cathode ray tube including an electron gun adjacent a rear end of the tube, for emitting an electron beam along a beam path from the electron gun through a funnel of the tube to a screen at a front of the tube, the apparatus comprising:
- a static convergence magnet assembly disposed over the electron gun;
- a primary deflection yoke including a core a vertical deflection coil for vertical deflection of the beam and a horizontal deflection coil for horizontal deflection of the beam, the horizontal deflection coil having end turns at a rear end, disposed substantially adjacent to the static convergence magnet;
- a scan velocity modulation coil for modifying said horizontal deflection of the electron beam, the scan velocity modulation coil located along the longitudinal axis of the tube forward and without overlap of the static convergence magnet assembly and rearward and without overlap of the core;
- and
- means for exciting the scan velocity modulation coil for varying a horizontal scan rate of said electron beam.
Dependencies are inferred from the claim text.