Cathode with optimised thermal efficiency
AssigneeThomson Licensing
InventorJean-Luc Ricaud
Life of this patent
Estimating the term…
Abstract
A cathode structure for an electron gun of a cathode-ray tube having a reduced size and providing a fast cathode start-up time and excellent thermal efficiency. The cathode comprises a closed chamber consisting of a cap supporting an emitting part of the cathode and a dish-shaped skirt having an internal surface which is concave so as to reflect, by radiation, the thermal energy stored in the skirt walls, towards that region of the cap supporting the emitting part. The cathode structure also comprises filament supply leads which pass through the side walls of the skirt and connect to the filament heater contained in the closed chamber.
Claims18
A cathode for an electron gun of a cathode-ray tube comprising an emitting part composed of emitting materials in order to generate an electron beam, a metal cap on which said emitting part is placed, a heater filament, of spiral shape, placed under the cap and terminated by connection leads, a skirt having an internal surface and surrounding the spiral part of said filament and forming, with said cap, a closed space, wherein
- said internal surface of a rear part of said skirt opposite said cap has a shape adapted to reflect heat energy from said filament towards said emitting part.
A cathode for an electron gun of a cathode-ray tube comprising an emitting part composed of emitting materials to emit an electron beam, a metal cap on which said emitting part is placed, a heater filament of spiral shape, placed under said cap and terminated by connection leads, a skirt surrounding the spiral part of said filament, said skirt being secured to said cap, said skirt having a side wall and a periphery, wherein
- said side wall of said skirt has openings and said leads pass through openings.
A cathode for an electron gun of a cathode-ray tube comprising:
- an emitting part composed of emitting materials in order to generate an electron beam;
- a metal cap on which said emitting part is placed;
- a heater filament, of spiral shape, placed under the cap and terminated by connection leads;
- a skirt, which has openings and an internal surface opposite said cap, surrounding the spiral part of said filament and forming, with said cap, a closed space, and
- a rigid support, wherein
- said openings through which said filament leads pass are notches placed in the periphery of said skirt close to said cap;
- at least one of said leads acts as a mechnical connection from the cathode to said support;
- and
- said internal surface is substantially frustoconical in shape to effectively reflect heat energy from said filament towards said emitting part.
Dependencies are inferred from the claim text.