Magnetron employing combined cold cathode head and production method of cold cathode body

Abstract

The invention provides a magnetron employing a combined cold cathode head and a production method of a cold cathode body in the cold cathode head. The magnetron comprises a magnetron shell, a blade, a cathode assembly and an antenna, wherein the magnetron shell comprises an upper tube shell, a lower tube shell, an input end ceramic cylinder, an output end ceramic cylinder, an exhaust pipe head, an anode tube, an upper magnetic pole and a lower magnetic pole; the blade is arranged in the anode tube; the cathode assembly comprises an upper shielding cap, a lower shielding cap, the combined cold cathode head and a power connecting rod; the combined cold cathode head comprises an electrode wire and the cold cathode body. The production method of the cold cathode body comprises a material preparation and ball-mill mixing step, a compression molding step and a sintering step. A lamp filament of a traditional hot cathode is taken as the electrode wire and is also taken as a secondary electron emitter; the cold cathode body forms field emission to generate primary electrons under the cathode-anode high-voltage action; and the temperature of the connected part of the power connecting rod and the lower shielding cap is lower than 500 DEG C during working, so that the magnetron has the characteristics of being high in emission current, stable in emission, high in efficiency, good in electromagnetic compatibility, long in lifetime, high in reliability, simple and reliable in production technology, low in cost and the like.

Description

technical field [0001] The invention relates to the technical field of a magnetron for microwave generation, in particular to a method for producing a magnetron using a combined cold cathode head and a cold cathode body in the cold cathode head, using the combined cold cathode head emission system The magnetron is especially suitable as a microwave source for microwave application equipment including domestic microwave ovens. Background technique [0002] Magnetron is the most widely used electronic vacuum tube. Because of its small size, high power, and convenient use, it is used as a microwave source for microwave application equipment including household microwave ovens. The cathode emission system in the magnetron structure is the heart of the whole tube. The working characteristics of the cathode have a great influence on the performance and life of the tube, so improving the working characteristics of the cathode has become an important research content; the convention...

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Problems solved by technology

When this type of traditional magnetron works normally, it needs to provide a certain current to the filament. The cathode needs to be heated with a power of about 40W between the center support and the upper electrode power connecting rod and the side support and the upper electrode power connecting rod. When the temperature rises to 800-1000°C, electrons are emitted, and the electrons bombard the cathode under the action of a magnetic field and raise its temperature to about 1800°C; working at such a high temperature will bring a series of problems, such as When the traditional magnetron is working, especially when it is intermittently working, it is repeatedly subjected to the influence of uneven stress such as expansion at high temperature and contraction at cooling, which will deform the high-voltage ceramics that are sealed and connected to the power connecting rod, seriously affecting the connection between the power connecting rod and the power supply. The tightness between the high-voltage ceramics reduces the vacuum degree of the magnetron, which in turn affects the performance and life of the magnetron; The electrons inside the body use additional energy to make some electrons escape across the surface barrier of the emitter to generate secondary harmonics and electromagnetic noise, which seriously affects the performance of the magnetron.

[0004] In the article "Film Field Emission Cold Cathode" (see "Optoelectronics Technology" No. 04, 1989, author: Chen Lifang et al.), a micro-electron source using a three-sandwich structure cold cathode is reported, which has room temperature work and no cathode work. consumption, no warm-up delay, etc., but it uses a planar emission structure, which needs to add a gate, and the emission current is small, so it cannot provide secondary electron emission; while the application number is CN201510675065.0, and the invention name is "A Kind of The carbon nanotube cold cathode disclosed in the patent document "Microwave Modulation Cold Cathode Micro-array Radiation Source and Its Realization Method" also adopts a planar emission structure, which cannot provide secondary electron emission and is not suitable for application in magnetrons; "Development of Ku-band Cold Cathode Magnetron" (see: Chinese Institute of Electronics Vacuum Electronics Branch - Fourteenth Annual Meeting, 2004, TN123, author: Zhou Caiyu et al.) discloses a method using cold cathode magnetron Provide primary electron emission, and use the primary electrons to bombard the surface of the secondary emitter to generate secondary electrons, but because it uses an alloy cathode structure, the ability of the primary electrons provided by the micro-tip field emission on the surface of the alloy cathode is insufficient, and the large pulse The transmission output power is only about 50kW, which is only suitable for use in medium and small tubes of Ka-band, Ku-band and X-band

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