Zenith Electronics Corporation

Wayne D Grocki

Gregory J Beaumont

Christopher S DeWaal

A stray magnetic field suppression system for use in a CRT image display suppresses a stray magnetic field that emanates from the horizontal deflection coil of a beam-deflecting yoke which is energized by sawtooth waveform pulses from a horizontal oscillator. The system comprises two series-connected magnetic coil assemblies in conjunction with a capacitor and activated by the sawtooth waveform pulses. The capacitor serves to integrate the pulses, enabling the suppression system to form an effective field for suppressing a stray magnetic field when the magnetic coil assemblies are interposed in the path of the stray magnetic field on opposite sides of the yoke.

Stray magnetic field suppresser for CRT image displays

A CRT image display emanates an undesired stray magnetic field that originates in the horizontal deflection coil of a beam-deflecting yoke energized by pulses from a horizontal oscillator circuit. A novel drop-in auxiliary pulse generator substantially electrically independent of the CRT image display, and synchronized with the output of the horizontal oscillator circuit, provides for energizing systems or devices that can suppress the stray magnetic field. The auxiliary pulse generator relieves the CRT horizontal oscillator of the burden of energizing a system for suppressing the stray magnetic field.

Pulse driver for CRT stray magnetic field cancelling circuit

An AC electric field emission suppressor for use in a CRT imaging system cancels the ripple voltage on the ultor voltage that generates the undesired emission. Ripple-cancelling pulses are derived from the horizontal deflection circuit and are capacitively coupled through the CRT wall to cancel the ripple voltage and suppress the undesired emission.

AC electric field emission suppression in CRT image displays

A stray magnetic field cancelling device for a cathode ray tube comprises an elongated member of adjustable length composed of at least two magnetizable metal plates in slidable relationship enveloped by an electromagnetic coil. The device is physically isolated from the yoke a distance effective to exert minimum effect on the yoke deflection fields. Also, the device is oriented transversely to the centerline of the cathode ray tube so as to generate a cancelling magnetic field in opposed relationship with, and transverse to, the stray magnetic field. A simple mechanical adjustment provides for adapting the device to CRTs of varying sizes.

Growing community of inventors

Libertyville, IL, United States of America

Wayne D Grocki