Back to results
US 4,422,014 AGranted
Method and apparatus for obtaining a focusable beam of electrons from a gaseous hollow-cathode discharge
OwnerDavid Glaserinventor
Life of this patent
Estimating the term…
Abstract
A flat-panel display employs an electronic focusing system which utilizes a repeller anode to repel low energy electrons emitted from a gas-discharge plasma which is controllably moved across a generally planar array of hollow-cathode elements.
Claims20
A method of exciting a luminescent target with a beam of electrons, comprising the steps of
- providing a source of free electrons,
- accelerating said electrons from said source toward said target by means of an electron-transmissive, positively charged electrode, and
- selectively repelling back to said electrode electrons transmitted by said electrode having less than a predetermined vector energy level.
A flat-panel display of the type in which a luminescent display screen is scanned by an electron beam, comprising
- an electron source including a planar hollow-cathode means in which a gas discharge is adapted to be provided,
- planar electron-transmissive extractor electrode means interposed between said hollow-cathode means and said screen for extracting electrons from a gas discharge in said hollow-cathode means,
- planar electron-transmissive repeller electrode means interposed between said extractor electrode means and said screen for repelling electrons transmitted through said extractor electrode having less than a predetermined energy level, and
- means for causing a gas discharge to scan said hollow cathode row by row,
- whereby said screen is scanned by a beam of electrons emanating from said hollow cathode.
2 more elements
For use in a cathodoluminescent display device of a type wherein a luminescent target is scanned by an electron beam, the combination comprising
- means including a cathode for generating a gas discharge for use as a source of electrons,
- an electron-transmissive extraction electrode spaced from said cathode and biased at a positive potential relative to said cathode for extracting electrons from said discharge,
- an electron-transmissive repeller electrode positioned in proximity to said extractor electrode for intercepting electrons from said source which pass through said extractor electrode,
- said repeller electrode being biased at a potential which is positive relative to said cathode and negative relative to said extractor electrode, and
- said extractor and repeller electrodes being spaced from said cathode by a distance substantially less than the mean free path of the electrons from said source,
- whereby only electrons having at least a predetermined energy level are transmitted by said repeller electrode.
3 more elements
Dependencies are inferred from the claim text.