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US 4,965,487 AGranted
Flat cathode ray tube display apparatus
AssigneeU.S. Philips Corporation
InventorKenneth G. Freeman
Life of this patent
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AssigneeU.S. Philips Corporation
InventorKenneth G. Freeman
Estimating the term…
In a flat cathode ray tube display apparatus a low energy, electron beam (18) is directed substantially parallel to a faceplate (12) carrying a phosphor screen (14) in a space between a deflection electrode array (22) and the input side of an electron multiplier (16) adjacent the screen where it is deflected by operation of the electrode array (22) in field scann manner towards the screen to provide a raster scanning input to the multiplier. the deflector electrodes (23) of the array are switched successively between two voltage levels in each field to step the line scanning beam with the switching voltages in successive fields differing whereby two interleaved sets of display lines are drawn in two consecutive fields which together constitute a display frame having the required number of active display lines. The voltage switching circuit (52) may be carried on a substrate adjacent the electrode array. For color display the screen comprises a pattern of different color phosphor elements and a selection electrode arrangement (38) is disposed adjacent the multiplier output side. Three differently colored, and accurately superimposed, sub-lines are drawn on the screen in a standard line scan period between stepping the beam.
A flat cathode ray tube apparatus comprising a cathode ray tube having an envelope, a luminescent screen extending over a substantially flat faceplate, means in the envelope for producing and directing an electron beam substantially parallel to the faceplate, and a deflection electrode array within the envelope and operable by a drive circuit for deflecting the beam in a direction towards said faceplate in field scanning manner, characterised in that the deflection electrode array comprises a plurality of deflector electrodes which are switched successively between two selected voltage levels in each field period to produce deflection fields with at least one of the selected voltage levels being different in alternate fields whereby in one field period one set of display lines is produced on the screen and in the successive field period a second set of display lines interlaced with the first set is produced.
Dependencies are inferred from the claim text.