US2444482A - Electron tube with external anode - Google Patents

Description

July 6, .1948. A. K. WING, JR 7 2,444,432 E ELECTRON TUBE W ITH EXTERNAL ANODE Filed March 14, 1946 VENTOR. ARTHUR KY wnve JR.

ATTORN Y Patented July c, 1948 2,444,482

ELECTRUN TUBE WITH EXTERNAL ANGDE Arthur K. Wing, 31a, Nutley, N. 3., assignor to Federal Telephone and Radio Corporation, New York, N. 1 a corporation of Delaware Application March 14, 1946, Serial No. 654,270

3 Claims. ((31. 250-2l.5)

l 2 The present invention relates to electron tubes by an envelope formed of a glass portion 4 and and more particularly to an electron tube having an anode portion 5. The anode portion 5 is an envelope, a portion of which is made of metal. flared and tapered to a knife edge 6 where it is In such a tube the envelope may be an elec sealed to the glass envelope 4.. The external electrode of the tube such as an anode. For best 5 trode is grooved at l around the entire tube and results it is desirable that the distribution of just below the flared knife edge portion 6. The

heat be uniform over the entire anode so that its groove '1 should be wide enough and deep enough entire surface will be effective in cooling the elecso that it leaves a relatively long thin section 8 trode. In the process of evacuating the tube of the metal wall which acts as a thermal imthe external electrode is also heated. The best to p d n we the main y of the de d vacuum is obtained when the distribution of heat the seal. In the form disclosed the thickness of over the metal envelope is uniform and the entire the section 8 is less than half the anode thickwall is maintained at the proper exhaust temness. perature. With such an arrangement heat is prevented Therefore an object of th present invention from flowing between the main body of the anode is to provide an electron tube having a thick elecand the seal and the seal may be oled ndetrode as an external envelope of the tube over pe de t y y any Suitable external means w Which the distribution of heat will be uniform, out affecting the uniform distribution of heat in The external electrode which forms part of the the a cdch d SadVan cS that arise from envelope of the electron tube is sealed. to the glass using merely a separate means for cooling the portion of the envelope of the tube. It has been electrode-to-glass seal are thus eliminated, By found that this seal may be damaged by the using my invention it is possible to provide a heat of the external electrode generated either thick Wall which will insure uniform heat distriduring operation or during evacuation, and so it bution, while at the same time retaining ease of is desirable that the electrode at the location of r processing which will allow the best degree of the glass seal be kept at alower temperature than vacuum to be obtained. At the same time the that of the metal portion of the envelope. Hereelectrode-to-glass seal is protected from overtcfore separate means have been provided for heatin cooling the external electrode near the glass-to- I do not intend to limit the invention to the metal seal, Such cooling means result in several preferred embodiment shown, except as may be detrimental features. In particular cooling eq e y the cl m Which wmeans has made a uniform distribution of heat What I claim is: diiflcult. Moreover, the thicker the wall for good 1. An electron tube comprising a glass portion heat conductivity and hence for uniform heat f ng t f e v p of said t a m a distribution the more need there is for cooling. e t ode f g a othe Part of the envelop Therefore a further object of my invention is U f d t e, a a mctal-to-glass S al cto provide an electron tube with an external electween, said metal electrode being t pered to a trode so formed that the electrode-to-glass seal point in the re o of Said Seal. a d electrode may be maintained below a temperature at which e ng subject n ts pe a g region to p the glass will soften and at the Same time the 40 tures detrimental o id m 1 0-s1ass l, distribution of heat over the electrode ma be and said electrode having an area of substantially uniform. reduced cross-section, said reduced cross-sec- A further object of my invention is to provide t l ar a mpl y s p r t ng sa d p ti an electron tube with an external electrode whose region from Said region about d Seal for thermal impedance is increased between the thick Venting t e flcW eat to d a electrode and the electrode-to-glass seal. An electron tube according 0 claim 1 in A more particular object of the invention is t Which the cross-sectional area is reduced so that increase the thermal impedance by decreasing the e e p t is less t an f the c o the thickness of the electrode at a region between Sectional area f the Test Of e electrode: the heated part of the external electrode and the An electron tube according o clalm 1 1n electrode-to glass Seal which the electrode is an anode of said tube.

Other objects and advantages of the present ARTHUR WING, invention will be seen from the following description of a preferred physical embodiment of REFERENCES CITED the invention and from the illustration thereof'in The following references are of record in the the accompanying drawing, in which the single fil of thi patent: figure is a central longitudinal cross section of a portion of an electron tube with an external UNITED STATES PATENTS electrode forming part of the envelope. Number Name Date In the figure a portion of an electron tube I, 2,049,238 Weth et al. July 28, 1936 is shown with a cathode 2 and grid 3 enclosed 2,173,906 Katsch o Sept. 26, 1939

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