Rca Licensing Corporation

Loren L Maninger

Bruce G Marks

David Arthur New

Stephen Thomas Opresko

Frank M Koch

Carl L Lundvall, Ii

A color picture tube includes a screen and an improved inline gun for generating and directing three inline electron beams along separate paths toward the screen. The gun includes a plurality of cathodes and at least six electrodes longitudinally spaced from the cathodes. The improvement comprises the first, second and fourth electrodes from the cathodes being of materials having lower coefficients of thermal expansion than the coefficients of thermal expansion of the materials of the other electrodes.

Color picture tube having an electron gun with reduced convergence drift

The present invention provides an improvement in a color display system. The system includes a cathode-ray tube having an electron gun for generating and directing three electron beams along paths toward a screen of the tube. The gun includes electrodes comprising a beam forming region, electrodes for forming a prefocus lens and electrodes for forming a main focusing lens. The system also includes a magnetic field deflection yoke. The improvement comprises means for applying a dynamic signal to one of the electrodes forming the prefocus lens when electron beam current drops below a predetermined level. The dynamic signal is a maximum voltage when there is no deflection of the electron beams and decreases in voltage to a minimum at maximum horizontal deflection of the electron beams.

Color display system

An improved method of making a color picture tube electron gun includes the selection and assembly of a plurality of cathodes and a plurality of electrodes longitudinally spaced from the cathodes. The improvement comprises at least three additional steps. First, the amount and direction of electron beam misconvergence at the tube screen, as caused by the thermal expansion of each individual electrode during electron gun warmup, is determined. A first group of electrodes will cause misconvergence in a first direction, and a second group of electrodes will cause misconvergence in a second direction. Second, the individual contributions of the electrodes to misconvergence during tube warmup are summed. The net effect of thermal expansion of the entire electron gun is a misconvergence in the first direction. Third, at least one of the electrodes in the first group of electrodes is formed from a material having a lower coefficient of thermal expansion than the coefficient of thermal expansion used in the first step of determining misconvergence caused by the thermal expansion of each individual electrode.

Method of making a color picture tube electron gun with reduced

An improved color display system includes a cathode-ray tube and a magnetic deflection yoke positioned on the tube. The tube includes an envelope having an inline electron gun for generating and directing three inline beams along initially coplanar paths toward a screen on an interior surface portion of the envelope. The gun includes a plurality of spaced electrodes which comprise three lenses. The first lens includes a beam-forming region for providing substantially symmetrical beams to a second lens. The second lens includes a first modulation electrode for providing asymmetrically-shaped beams to a third, or main, lens. At least one and preferably two dynamic voltage signals are applied to the modulation electrode of the second lens. Another dynamic voltage signal is applied to a second modulation electrode of the third lens. The voltage signals are related to the deflection of the beams and improve the electron beam spot size at the periphery of the tube screen.

Color display system having an electron gun with dual electrode

The present invention provides an improved electron gun in a color picture tube. Such electron gun includes a beam-forming region comprising cathodes and at least two electrodes and a main focus lens formed by two electrodes. The cathodes and all of the electrodes are interconnected to a plurality of insulative support rods. The improvement comprises forming a first focus lens electrode, nearest the beam-forming region, of two separated portions that are electrically connected. The portion of the first focus lens electrode that is nearest the other focus lens electrode only is interconnected to the support rods near the main focus lens. The portion of the first focus lens electrode that is nearest the beam-forming region is connected to the support rods immediately adjacent to a beam-forming electrode.

The present invention provides an improvement in color cathode-ray tubes. Such tubes include an electron gun for generating and directing three inline beams, a center beam and two side beams, along initially coplanar paths toward a screen of the tube. The gun includes a plurality of spaced electrodes which provide a first, a second and a third lens for focusing the electron beams. The first lens has a beam forming region for providing substantially symmetrical beams to the second lens. The improvement comprises the combination of the second and third lens. The second lens includes at least one electrode to provide asymmetrically-shaped beams. The potentials applied to the second lens refract electron beams emerging off-axes from the first lens toward the axes. The third lens is a low aberration main focusing lens which provides asymmetrically-shaped beams of substantially constant current density to the screen.

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Lancaster, PA, United States of America

Loren L Maninger