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US 4,456,853 AGranted
Feedback CRT for use in a closed-loop correction system
AssigneeTektronix, Inc.
InventorsRonald C. Robinder, David J. Bates, Dan F. Denham
Life of this patent
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AssigneeTektronix, Inc.
InventorsRonald C. Robinder, David J. Bates, Dan F. Denham
Estimating the term…
A cathode-ray tube including feedback means capable of producing a feedback signal indicative of the position, in at least two dimensions, of a scanning electron beam. The feedback means comprises a plurality of feedback elements disposed at selected locations within the tube enclosure. With a shadow-mask type CRT, the elements are formed on the gun-side surface of the shadow mask itself. With other kinds of CRT's, the elements are formed either on an interior supporting member or on the interior surface of the display medium. In one embodiment, the elements are formed of a phosphorescent material. In other embodiments, the elements are formed of materials capable of producing, upon excitation by a scanning electron beam, signals of visual or electrical character. The signals thus produced may be employed in a closed-loop correction system to accomplish automatic convergence and/or geometric adjustment of a displayed image.
A cathode-ray tube comprising a display screen of phosphorescent material, an electron gun for producing an electron beam directed toward said display screen, a shadow mask interposed between said electron gun and said display screen, and a feedback element disposed at a preselected location on a surface of said shadow mask, said element being formed of a material capable of providing a detectable response upon bombardment by said beam and configured to provide, upon scanning by the beam, information denoting the location of the beam in two dimensions.
In a cathode-ray tube of the kind including a display screen, an electron gun, and a shadow mask interposed therebetween, the improvement comprising:
A cathode-ray tube shadow mask unit for use in a beam position feedback-type CRT, said mask unit comprising a perforated metal sheet and feedback means associated therewith for providing, upon scanning of the sheet by an electron beam, information denoting the beam's intercept location in two dimensions.
Dependencies are inferred from the claim text.