US 4,812,707 A · Traveling wave push-pull electron beam deflection structure having voltage gradient compensation

Abstract

An electron beam deflection structure (10) of the traveling wave type effectively cancels the longitudinal voltage gradients and the associated electron beam defocusing that are characteristic of such deflection structures. The deflection structure comprises a first helical coil member (48) and a second helical coil member (50) that are coaxial with the longitudinal axis (26) of the tube. Each of the coil members has wide and narrow segments which alternate along the length of the coil in sequence with the turns of the coil. The first coil member has its wide segments (92a) positioned on the bottom and its narrow segment (92b) on top of the coil member. The second coil member has its wide segments (94a) positioned on top and its narrow segments (94b) positioned on the bottom of the coil member. The narrow segments from one of the coil members are interleaved with the wide segments from the other coil member. A pair of linear arrays (100) and (102) are thereby formed which are positioned above and below the electron beam path and comprise wide and narrow segments from different coil members. Differential voltage signals of opposite polarity are applied to the first and second coil members of the deflection structure. Longitudinal voltage gradients along the wide segments are compensated by substantially equal but opposite voltage gradients on the narrow segments, thereby effectively canceling the longitudinal voltage gradients and eliminating any defocusing of the electron beam that the voltage gradients would cause.

Claims15

Dependent claims

An electron beam deflection structure for use in an electron discharge tube having a central longitudinal axis extending along the direction of electron beam propagation, comprising:

a pair of bifilar helical coils coaxial with said central longitudinal axis, each of said coils including alternating plate segments of substantially greater area and substantially lesser area, the plate segments of the coils being interlaced together along the lengths thereof to form a pair of linear arrays which extend along said central longitudinal axis and are positioned on opposite sides of said axis, each of said arrays including plates of greater area from one of said coils and the plates of lesser area from the other of said coils.

A cathode-ray tube, comprising:

beam emitting means positioned near one end of said tube for directing an electron beam along a central longitudinal axis in said tube toward a display screen positioned near an opposite end of said tube;
and
an electron beam deflection structure including a pair of helical coils coaxially positioned with respect to said axis and interlaced in a bifilar fashion, each of said coils including alternating beam deflection segments of substantially greater area and of substantially lesser area positioned on opposite sides of said axis, said beam deflection segments of said coils being interlaced together along the lengths thereof to form on each of said sides a linear array having said beam deflection segments of substantially greater area from one of said coils and said beam deflection segments of substantially lesser area from the other of said coils.

Dependencies are inferred from the claim text.

Traveling wave push-pull electron beam deflection structure having voltage gradient compensation

Life of this patent

Traveling wave push-pull electron beam deflection structure having voltage gradient compensation

Life of this patent

Abstract

Claims15