US2380757A

US2380757A - Electron discharge tube

Info

Publication number: US2380757A
Application number: US551883A
Authority: US
Inventors: Herne Howard James Louis
Original assignee: Hartford National Bank and Trust Co
Current assignee: Hartford National Bank and Trust Co
Priority date: 1943-05-10
Filing date: 1944-08-30
Publication date: 1945-07-31
Anticipated expiration: 1962-07-31

Description

July 31,'1945. l H. J. L. HERNE V2,380,757

l LECTRON DISCHARGE TUBE ,I

Fild Aug. 5or 1944 Patented July 3,1,y '1945 Howard James Louis Herne, London, England, as-

signor to' The Hartford National Bank and Trust Company, Hartford. Conn.,l as trustee Application August so, 1944, seriali No. 551,883

y In Greet Britain May 10,1943

Y comme. A(ci. 25o-21.5)

This inventionl relates to electron discharge tubes and has forits object to provide a convenient electrode assembly whereby two adjacent electrodes are secured in predetermined relationshipunder operating conditional According to the present invention the said two electrodes are carried by common supports sealed inthe envelope, 4one electrode beingdirectly carried by thesupports which also constitute the electrical connection to this electrode and the other being indirectly carried by wy'of insulating beads of glass or other thermoplastic material which does not soften under the conditions obtaining during normal operation of the tube, the electrical connection to this other electrodebeing eected by a separate leadin wire.'

In a preferred construction according to the Fig. 1 is o. longitudinal section through the electron discharge tube, prior to the sealing oi! of the envelope.

` present inventiontwo support wires sealed in the g envelope arel welded or otherwise secured to one.

electrode and are stepped outwardly away from the electrode system and extend beyond' the active Fig.l 2 is a cross section substantially along the line II--ll of Fig. 1.

Fig. 3 is a cross-sectional view of the snode lead-in conductor.'

The discharge tube shown is a diode, the cathode I and thefanodell each consisting of a pot' or I cup-shaped electrode, the closed ends being adjacent each other. l f

Sealed in one end ofthe glass envelope I are support and lead-in wires 2, l for the cathode as well as a further lead-in'wire 4 for the cathode heater 0, the circuit of ywhich is completed by way of the cathode support 3. The upper ends of the wires, 2.. 3, .4, are located by a mica disc B which has apertures for -the passage of the wires and which is supported by metal collars i, 1, on the support wires 2, 3. The pot cathode l is welded to two metal wiresIII, I I, the lower ends of which face of the said one electrode. vthe ends of the Y wires being sealed` in insulating beads in each of `which is also-sealed one end of a ,wire the other end of which is Vsecured to the second electrode. `the insulating. beads forming an insulating mechanical connection between the two sets ofA wires.

present invention is applicable with particular' advantage to electron discharge tubes in which two adjacent electrodes are substantially in contact, onegof'th'e electrodes being coated Y with aninsulatingcoating preferably in the form ofan emissive oxide coating... In thel usev of a."

. .contact diode.; bothcathode and anode are convenlently constructed ascup or potshaped-electrodes'andare mounted with their closed ends in contact.'y they vcathode :directly on -is preferably ilexible'fp'r instancevin the form-of so es to support the latter. with its closed VVure attached to the upper ends of the wires i, i.

The upper parts of the wires Il, Il are stepped outwardly away from the cathode I and are embedded in glass beads I2, I8.' .Also embedded in the lglass beads l2, II and insulated. by the glass y from the rods Il. Il are metal wires Il, Il of substantially 4.I or LI shape. The free ends oi these wires Il, Il are welded to the pot anode I6 adjacent the closed end of the cathode 8. f

Secured to the wires M, I5 is a me'istlv cross `-wire I-I to which the anode lead-in conductor is attached. This conductor` consists of a wire I8 and a flexible metal strip It which preferably has a zig-mg or corrugated portion-as shown in a strip or nbbouettsohed stone to the .anode` i' and at ,the otherfendjtoyfalead in conductor Wed in; *he'livelwetthef strinfm" prisinsfs' linens 'for eo icngfinter- 'rhe gmsgheaqs andthe twoelectrodgs-are chosen 'of -suehl-eoemf I cient of the' points of Vattitchment `ci the tutheeiectrodes are so selected.- that at the-worlcing` temperatures oifthecomponenta of the tube, the' two creat desired spacing.

ins drawing. which `one embodiment oi the invention by way of'example and in which ferencefwill rto" Fig. 3. 'Ihe anode lead-inconductor is located `within the envelope by amica disc 2l held be- 'twejentwa collars, 2|, `2! on the wire I9. For' facilitating" the sealing-0E, 'fthe wire VIl is `pm'tfitiea with e gloss heed n vwhich otter the' discharge tube has been degassed isfused to the glass of'they'envelopc. I e v With-anindirectly heated cathode l as shown,

the surfaceadjacent the anode I8 will be coated in the usual waywith an emisslve oxide coating. The anode I and cathode I may be at a perceptible separation' as shown. or they may be substantially in contact but insulated from each otherby the oxide# I t Fonobtaining contact betweenthe two electrodest. it or 'only-avery alight separation it is preferred to proceed as follows: the' electrode assembly 2--2'3 is nrstmade-with the surfaces of :the electrodes). tlm contact. 'nie assembly is'l then introduced into the envelope I through the lower end, and the seal is produced about the support wires 2', 3 and the heater lead 4 which are to pass through this end of the tube. The tube is then connected with the pumps and degassing is effected. While still on the pumps, the cathode 8 is heated to such an extent that the glass beads I 4, I5 soften adjacent the end of the wires I0, II. The heating may be effected by the cathode heating coil 9, by eddy current heating, or by the two in combination. In any case, the wires I0, II are'heatedlchiey by conduction from the cathode 8. When the glass beads I2, I3 soften, the anode I6 simply rests on the cathode 8. On cooling, the glass of the beads I2, I3 first hardens, and then in accordance with the different coefiicients of expansion and the different expanding lengths, the surfaces of the electrodes are caused to assume a predetermined spacing at the working temperature of the tube; the spacing may be perceptible or may be vanishingly small. After this heating stage and after completed degassing, the tube is sealed off by fusing the bead 23 to the neck of the tube. The mica disc 20 secured on the lead-in conductor I 9 prevents any undesired outward movement of the latter relatively to the tube during the sealing-off operation.

Although the drawing shows the invention as applied to a diode, it will be apparent that the invention can be applied to an electron discharge tube with more than two electrodes, by providing a sequence oi' alternate insulating beads I2, I3 and supporting Wires I 4. I5, all carried by the primary supports 2, 3 which are sealed into the envelope.

I claim:

1. An electron discharge tube wherein two adjacent electrodes are carried by common supports sealed in the envelope, one electrode being directly carried by .the supports which also constitute the electrical connection to this electrode, and the other being indirectly carried by way of insulating beads oi' thermoplastic material which does not soften under lthe conditions obtaining during normal operation of the tube, the electrical connection to this other electrode being efl'ected by a separate lead-in- Wire.

2. An electron discharge tube as claimed in claim 1, wherein .two support wires sealed in the envelope are secured to one electrode and are stepped outwardly away from the electrode system and extend beyond the active face of the said one electrode, the ends of the wires being sealed in insulating beads in each of which is also sealed one end of a wire the other end of which is secured to the second electrode, the insulating beads forming an insulating mechanical connection between the two sets of wires.

3. A diode comprising a cathode, cathode support and lead-in wires sealed in the envelope and secured to the cathode, an anode rigidly carried by the cathode supports by means including insulating beads of thermoplastic material ,which does not soften under the conditions obtaining during normal operation of the diode, and a separate lead-in wire connected .to the anode.v

4. An electron discharge tube comprising an envelope, two adjacent electrodes and common supports for said electrodes sealed in the envelope, said supports directly carrying one of said electrodes and constituting the electrical connection thereto, insulating beads consisting of a glass which does not soften under the conditions obtaining during normal operation of the tube secured to said supports and to the other electrode for indirectly carrying said other electrode on said common support, and a separate lead-in wire constituting the electrical connection to said other electrode.

5. An electron discharge tube comprising an envelope, two adjacent electrodes substantially' in contact and common supports for said electrodes sealed in the envelope, an insulating coating on one of said electrodes, said supports directly carrying one of said electrodes and constituting the electrical connection thereto, insulating beads of thermoplastic material which does not soften under the conditions obtaining during normal operation of the tube secured to said supports and to the other electrode for indirectly carrying said other electrode on said common supports, and a separate lead-in wire constituting theelectrical connection to said other electrode.

6. An electron discharge tube comprising an envelope, a cathode electrode, another electrode adjacent to and substantially in contact with said cathode and common supports for said electrodes sealed in the envelope, an emissive oxide coating on said cathode, said supports directly carrying one o1' said electrodes and constituting the electrical connection thereto, insulating beads of thermoplastic material which does not soften under conditions obtaining during normal operation of the tube secured to said supports and to the other electrode for indirectly carrying said other electrode on said common supports, and a separate lead-in wire constituting' the electrical connection .to said other electrode.

7. In the method of manufacturing an electron discharge tube having an envelope, two adjacent electrodes substantially in contact and common supports for said electrodes sealed in the envelope the steps comprising, directly securing one of said electrodes to said supports, securing on said supports insulating beads of a thermoplastic material which does not soften under conditions obtaining during normal operation of the tube, nxedly securing the other of said electrodes to said insulating beads in a position adjacent to and substantially inv contact with said directly secured electrode, sealing the said supports to one end of the envelope, and heating the said insulating beads .to soften the same and lpermit movement oi' the electrodes relative to each other.

nowann JAMEs Louis Imam;