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US 4,792,718 AGranted
Cathode ray display tubes
AssigneeU.S. Philips Corporation
InventorAlan G. Knapp
Life of this patent
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AssigneeU.S. Philips Corporation
InventorAlan G. Knapp
Estimating the term…
In a display tube a laminated dynode channel plate electron multiplier (16) produces at its channel outputs (50) a current-multiplied beam (34) in response to an electron beam being scanned thereover which is accelerated towards a phosphor screen (14) comprising repeating groups of different color phosphor elements and selectively directed onto particular elements by color selection deflector electrodes (38,40) adjacent the channel outputs. To provide increased horizontal resolution capability the exits (50) of the apertures in the final dynode are elongate in shape, other dynodes having circular apertures, and arranged parallel to one another with their longer axes extending vertically to form a comparatively narrow horizontal width output beam. The final dynode aperture entrances may be similarly elongate or circular with the apertures having a re-entrant profile. An apertured extractor electrode (36) disposed between the multiplier and color selection electrodes may also have elongated apertures (42) to enhance this beam shaping.
A cathode ray display tube comprising means for producing an electron beam, a channel plate electron multiplier for producing at its output side current multiplied electron beams in response to the electron multiplier being scanned by the electron beam over its input side, the channel plate electron multiplier comprising a stack of a plurality of apertured dynodes, the apertures of the dynodes being aligned to provide channels through the stack, a phosphor screen comprising repeating groups of phosphor elements and colour selection means operable to direct selectively the electron beams from the channel multiplier onto the respective phosphor elements, wherein the exits of the apertures in the final dynode at the side thereof adjacent the colour selection means are elongate in shape and oriented substantially parallel to one another.
Dependencies are inferred from the claim text.