Rca Inc.

Thomson Consumer Electronics Inc.

Rca Licensing Corporation

Leroy W Nero

Ronald E Fernsler

Wolfgang F Dietz

Robert Joseph Gries

David Ross Jackson

John Charles Peer

A projection television receiver has a cathode ray tube with an electron gun for emitting an electron beam incident on a screen, an electromagnetic deflection yoke and an electromagnetic focusing coil. A horizontal deflection driving circuit is coupled to a horizontal deflection coil and provides deflection current to the horizontal deflection coil for scanning the beam repetitively on the screen. The focusing coil is driven from a current step-down transformer having a primary winding coupled in series with the horizontal deflection coil. A secondary winding of the transformer is coupled to the focusing coil for driving the focusing coil with a horizontal rate parabolic current. A capacitor-resistor circuit is coupled in parallel with the focusing coil and with the secondary winding of the transformer for adjusting a phase relationship of the parabolic current relative to the horizontal deflection current and for adjusting the amplitude of the parabolic current.

Focus coil current generator for a cathode ray tube

A driver stage of a horizontal deflection output transistor includes a transformer having a first winding coupled to a collector of a second, driver transistor responsive to an input signal at a horizontal deflection frequency. A second winding of the transformer is coupled across a base-emitter junction of the output transistor and a third winding is coupled to the emitter of and in series with the output transistor. The third winding couples the emitter current to the base of the output transistor for supplying a substantial portion of the base current during the second half of trace. A feedback network is coupled between a trace capacitor coupled to a horizontal deflection winding and the collector of the driver transistor for preventing abnormal steady state operation in the output transistor.

Feedback arrangement in a deflection circuit

A high voltage transformer for a video apparatus provides electrical isolation between the primary and secondary windings. The primary winding is wound on a first bobbin while the secondary windings are wound on a second separate bobbin that surrounds the first bobbin with the bobbin structure providing a physical isolation barrier. The high voltage winding is wound on a high voltage bobbin which fits over the primary and secondary bobbin structure.

Isolating high voltage transformer for video apparatus

A video display apparatus includes a cathode ray tube and a high voltage transformer. The high voltage transformer incorporates a high voltage winding having a tap which provides a focus voltage for the electron gun assembly of the cathode ray tube. The transformer also includes a supply winding which provides power to the electron gun assembly drive circuit. The supply winding is wound to be closely coupled to the portion of the high voltage winding not associated with the generation of focus voltage so that increasing beam current produces nonuniform loading of the high voltage winding.

CRT focus tracking arrangement

A high voltage transformer incorporates a bobbin on which the primary winding is wound. The transformer auxiliary coils are wound directly over the primary winding with no intermediate layers of insulation. The wire turns of the auxiliary coils are evenly distributed over the full traverse of the primary winding to improve magnetic coupling and simplify tuning of the transformer.

Transformer winding arrangement for a television apparatus

A core gap spacing arrangement for a transformer includes a length of twisted wire pair. The twisted pair has a relatively low packing density and is therefore compressible over a large range by using relatively low compression forces, resulting in greater ability to accurately adjust the inductance of the transformer primary winding.

Inductance adjustment for transformers

In a television receiver having a picture tube that requires an ultor accelerating potential and an intermediate direct voltage, such as a focus voltage, a high voltage generator is provided that develops the two voltages. A source of alternating voltage is coupled to a primary winding of a transformer for developing an alternating polarity voltage across each of two high voltage secondary windings. A first voltage doubler is coupled to the first high voltage winding for rectifying the alternating polarity voltage developed across the winding during both polarity intervals thereof to produce a first direct voltage. The first direct voltage is applied to an intermediate voltage terminal to generate the picture tube intermediate direct voltage between that terminal and a reference terminal. A second voltage doubler is coupled to the second high voltage winding for rectifying the alternating polarity voltage developed across the winding during both polarity intervals thereof to produce a second direct voltage. The first and second direct voltages are combined and applied to an ultor terminal to generate the picture tube ultor accelerating potential between this terminal and the reference terminal.

Television receiver high voltage generator

A combined magnetic shielding and degaussing structure for an in-line color picture tube comprises magnetizable shielding plates of an extended surface area each located at a corner of the picture tube and two vertically oriented magnetizable strips. Each strip connects upper and lower corner shielding plates on one side of the picture tube. The shielding plates guide stray magnetic flux into the strips and away from the picture tube interior in order to provide magnetic shielding. A degaussing winding is wound around the vertical axis of each strip and generates a degaussing flux which flows through the shielding plates and into the color picture tube shadow mask.

Color picture tube magnetic shielding and degaussing structure

An electronic regulator produces a regulated direct voltage less than the raw direct voltage input. The load on the regulated output is the primary winding of the horizontal output transformer of a television horizontal deflection circuit. A secondary winding of the output transformer is connected in series with the source of raw direct voltage. An energy storage capacitor is coupled across the secondary winding, and charged therefrom by a gated rectifier. The regulated output voltage is taken across the raw direct voltage source and capacitor. An overvoltage protection circuit for protecting against fault conditions is provided. The protection circuit includes a diode coupled between the regulated output voltage terminal and the raw input voltage terminal. The diode is normally back-biased and becomes conductive when a fault condition makes the regulated voltage exceed the raw input voltage. A resistor in series with the secondary winding controls circulating currents in the event of an overvoltage fault.

Overvoltage protected de-boost regulator

A horizontal deflection circuit comprises a deflection winding, an output deflection circuit for generating deflection current and retrace pulses, an oscillator and driver circuit for providing drive signals to the output deflection circuit, a frequency and phase control circuit for synchronizing the deflection current with incoming sync pulses, and a correction circuit. The correction circuit corrects for variations in initiation of retrace which are not adjusted by the frequency and phase control circuit, such as caused by variations in storage time delay of an output transistor. The correction circuit includes a sawtooth generator for obtaining a sawtooth voltage from a retrace pulse and a peak separator to which the sawtooth voltage is coupled for generating voltage pulses for providing a correction voltage to the oscillator and driver circuit.

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Indianapolis, IN, United States of America

Leroy W Nero