Flat cathode-ray tube for direct viewing spot display

Claim 1

A cathode-ray tube which comprises, inside an evacuated envelope, at least a portion of which is transparent, an electron-gun and an electron collector, said gun comprising a cathode in form of a first elongated surface, and at least one control electrode and comprising two additional flat plates extending in the direction of said cathode and perpendicularly to its surFace, one of which called the first electrode plate, visible through said transparent portion, is transparent and is covered, on that face disposed towards the other of said two additional plates with a thin, transparent, conductive film itself coated with a cathodoluminescent material, and the other of which, called the second plate, carries parallel conductive strips insulated from one another and extending across the large side of said surface, in the form of rectangles whose large sides are parallel to the large side of said surface, wherein said cathode is a flat rectangular metal strip covered at intervals with small areas of an electron-emissive material and said control electrode is a flat rectangular strip of insulating material parallel to said cathode and pierced by spaced holes said holes being ordered by conductive eyelets electrically insulated from one another, a further flat rectangular metal electrode also parallel to said strip on the side thereof corresponding to electron flow pierced by spaced holes, said emmissive areas, eyelets and holes all respectively aligned and substantially equal in size with each other and disposed in a direction substantially perpendicular to said cathode, each of said eyelets, provided with a separate connection, enabling separate individual control of the emission of one of said small areas to be effected; all of these electron beams emitted by these areas propagating in the same direction perpendicular to this surface and wherein are provided means for applying a fixed voltage to said film and for separately applying voltages to said eyelets and to said strips with regard to said cathode to bend the electron beams into scanning said first plate.