US2841734A

US2841734A - High frequency electric discharge device

Info

Publication number: US2841734A
Application number: US344957A
Authority: US
Inventors: Clifford E Horton; Hsu Hsiung
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1953-03-27
Filing date: 1953-03-27
Publication date: 1958-07-01
Anticipated expiration: 1975-07-01

Description

July 1, 1958 c. E. HORTON ETAL HIGH FREQUENCY ELECTRIC DISCHARGE DEVICE 7 Filed March 27, 1953 Fig. 3.

Inventors: "C|iFFord E.I-Ior-ton Hsiung Hsu, M

- Their Attorney.

Zilllfldd Patented July 1, 1958 HIGH FREQUENCY ELECTRIC DISCHARGE DEVICE Cliiiord E. Horton and Hsiung Hen, Owensboro, Ky., as signors to General Electric Company, a corporation of New York Application March 2'7, 1953, Serial No. 344,957 9 Claims. (Cl. 313-24tl) facture which characterizes more conventional receiving type tubes. Previous attempts to provide tubes for satisfactory operation in this range have involved structures which are rather expensive to manufacture. The disk seal or lighthouse tube is one well-known prior art type of device capable of operating in this high frequency range but as is readily appreciated by those skilled in the art these tubes, involving large sealing areas, are rather expensive to manufacture and are not well suited for mass production at a price which is attractive for such applications as television receivers.

The present invention has for an important object the provision of a high frequency tube design particularly suited for grounded grid operation and lending itself to usual mass production techniques employed for receiving type tubes.

It is a further object of the invention to provide a high frequency electric discharge device of single ended construction.

It is a still further object of the invention to provide an improved high frequency electric discharge device in which the grid inductance common to the input and output circuits is minimized.

It is still another object of the invention to provide a simplified structure for a high frequency electric discharge device which is characterized in its operation by a minimum variation of input impedance with frequency due to feed through resulting from coupling between the input and output circuits.

Further objects and advantages of the present invention will become apparent as the following description proceeds, reference being had to the accompanying drawing and its scope will be pointed out in the appended claims. In the drawing,

Figure l is a perspective view partially broken away showing an electric discharge device embodying our invention:

Figure 2 is an enlarged perspective view of a part of the device shown in Figure 1 with the parts partially broken away and with the length of the lead-in conductors exaggerated to show their location in relation to the electrodes to which they are connected; and

Figure 3 is a flux plot showing the degree of inductive isolation between the input and output circuits of the device. 7

Referring now to the drawing, the present invention has been shown embodied in a triode device particularly suited for use as a grounded grid amplifier at frequencies up to 900 megacycles. The device as illustrated comprises a standard miniature tube envelope 1 including a stem or header 2 through which the nine pins or lead-in conductors, designated by numerals 3-11, inclusive, are sealed in a circular array.

The electrode assembly or mount includes an indirectly heated cathode 12, a grid 13 including a pair of spaced

side rods

14 and 15 and an overwound wire l6 and a box like anode 17. As illustrated, the cathode sleeve 12 is rectangular in cross section and is heated by a filamentary heater element having terminals 13 and 19 connected with lead-in conductors i and 5. Unlike most receiving type tubes, the mount structure in accord ance with one feature of the present invention is mounted with the axis thereof horizontal, that is transverse with respect to the axis of the envelope 1 and the flattened grid is mounted in a generally horizontal plane. In accordance with the usual practice, the electrodes are supported in mutually insulated relation by means of a pair of insulating spacer members 249 and 21 (shown only in Fig. 1).

One of the requirements for high frequency operation of a grounded grid tube is that the grid and associated structure provide a rather efiective shield between the anode and cathode. In accordance with the present invention this is accomplished by specially designed con ducting or shield members which are secured to the

grid side rods

14 and 15 at opposite ends of the mount and on the exterior of the spacers 2d and 21. As illustrated, conducting members or

shields

22 and 23 include a flat portion 24 which is bonded to the extending ends of the grid side rods and form essentially extensions of the grid plane. From these portions 24 the shields each include a depending portion 25 which extends at right angles thereto and then extends inwardly toward the

spacers

20 and 21.

While the arrangement of the shields just described is a very important consideration with respect to the shielding between the cathode and anode and the resulting reduction in the capacitive coupling between these electrodes, the arrangement of the lead-in conductors with respect to the various electrodes and particularly with respect to the shield members forms an important part of the present invention and particularly contributes to the effective inductive isolation of the input and output circuits, that is, the circuit between the grid and cathode on the one hand and the grid and anode on the other. From Figs. 1, 2, and 3, it will be apparent that the lead-in conductors are connected to the various electrodes in the following order: Conductors 3 and 6 are connected to opposite edges of the shield member 22 connected to the grid at one end; lead-in conductors 4- and 5 are connected to the heater leads; lead-in conductor 7 is connected directly to the anode between the insulating spacers and also between the shield members 22 and and lead-in conductors 8 and iii are connected to opposite edges of the shield member 23 at the opposite end of the mount, with conductor 9 connected to tie shield member near the middle thereof in rather close prerimity to the lead-in conductor iti which is connected with the cathode sleeve.

The multiple grid connections described above tend to minimize the total inductance in the grid circuit connections. More important, however, to the successful operation of this tube at high frequencies is the relatively complete inductive isolation of the input and output circuits resulting from the location of the lead-in. conductors relative to each other and to the associated electrodes. It will be noted from a consideration of Fig. 3 that the fields associated with the grid-plate circuit (conductor 7 and edges of shields connected to lead-ins 6 and 3) are essentially isolated from the fields associated with the grid-cathode circuit (conductor 10 and central portion of shield connected with lead-in 9). In effect, diiferent portions of the grid shields and diiterent grid lead-in conductors are involved in the grid-plate circuit from the 3 grid lead-ins and portions of the grid shield involved in the grid-cathode circuit.

This construction has been found to provide a very marked improvement in the highfrequency characteristics of the device and, as will be apparent to those srilled in the art, is accomplished without any substantial complication of the structure froma general manufacturing and assembly standpoint. The tube still remains, as far as the basic manufacturing steps are involved, a single ended receiving type tube involving a stem, an envelope, and an eiectrode mount.

While we have described and claimed the particular embodiment of our invention, it will be apparent to those skilled in the art, that changes and modifications may be made without departing from our invention in its broader aspects, and we aim therefore in the appended claims to cover all such changes and modifications as fall Within the true spirit and scope of our invention.

What we claim as new and desire to secure by Letters Patent of the United tates is:

l. A high frequency electric discharge device for grounded grid operation including a generally cylindrical envelope including a closure at one end having a plurality of lead-in conductors sealed therethrough in a ircuiar array, an electrode mount including a cathode, a grid, an anode supported in mutually insulated and concentric relation in the order named with the anode the outermost electrode, means supporting said electrode mount in said envelope with the axis extending generally transverse to the axis of said envelope, a shield member extending outwardly from each end of said grid and downwardly toward said closure, lead-in conductors connected to each of said shields near opposite edges thereof and providing grid circuit connections, a lead-in conductor connected with said anode between said shields and extending through said closure member between lead-in conductors connected with different ones of said shields, and a cathode connection with a lead-in conductor psi tioned between the lead-in conductors connected with one of said shields to limit the inductive coupling between said grid-anode circuit on the one hand and the grid cathode-circuit on the other.

2. An electric discharge device including an elongated envelope including a closure at one end having a plurality of lead-in conductors sealed therethrough, an anode, a control grid, and a cathode supported in insulated relation within said envelope and extending generally transverse to the axis of said envelope, shield members of conducting material connected with and forming an extension of each end of said control grid and each'in-' eluding a portion extending toward said closure, one of said lead-in conductors being connected with said anode between said portions, another of said lead-in conductors being connected with said cathode and located on the opposite side of one of said portions and a lead-in conductor connected with each of said portions.

3. An electric discharge device including an elongated envelope including a closure at one end having a plurality of leaddn conductors sealed therethrough, an anode, a control grid, and a cathode supported in insulated relation within said envelope and extending generally transverse to axis of said envelope, a shield member of conducting material connected with an forming an extension of said control grid and including a portion extending toward said closure, one of said lead-in conductors being connected with said anode on one side of said portion, another of said lead-in conductors being connected with said cathode and located on the opposite side of said portion and at least two lead-in conductors connected with said portion.

A high frequency electric discharge device for grounded grid operation including an anode, a cathode, and acontrol grid interposed therebetween, a conducting member of extended area connected to provide smooth electrical continuity with said control grid, a lead-incon- 4 ductor connected with said anode and lying on one side of said conducting member, a lead-in conductor connected with said cathode and located on the opposite side of said conducting member, and first and second lead-in conductors connected with said conducting member, said first l ad-in conductor being closer to the 1ead-in conductor connected with the anode and the second lead-in conductor being closer to the lead-in conductor connected with the cathode.

5. A high frequency electric discharge device for grounded grid operation including an anode, a cathode, and a control grid interposed therebeween, conducting members extending from each end of said gid member and a plurality of lead-in conductors connected with said electrodes including at least two conductors connected with each of said conducting members, a lead-in conductor connected with said anode and l cated between the connectors connected with one said conducting members and the conductors connected with the other of said conducting members, and a lead-in conductor con nected with said cathode and located between the lead-in conductors connected with one of said conducting memhers.

6. A high frequency eiectric discharge device grounded grid operation including a cylindr "ivciops, an elcctrodemount including an anode, a cathode, and a control grid interposed therebetween, said mount extending transversely to the axis of said envelope, conducting members extending from each end of s d grid member and toward the end of said envelope, a plurality of lead-in conductors extending through said end of said envelope and connected with said electrodes including at least two conductors connected with each of said conducting members, a lead-in conductor connected with said anode and located between the conductors connected with one of said conducting members and the conductors connected with the other of said conducting members, and a lead-in conductor connected with said cathode and located between the lead-in conductors connected withone of said conducting members.

7. An electric discharge device including an envelope including a closure at one end having a plurality of lead-in conductors sealed therethrough, an anode, a grid and a. cathode supported in insulated relation within said envelope, a conducting member connected to at least two spaced points of said grid and forming an extension thereof, said member having a first portion substantially coplanar with said grid and a second portion extending to Ward said closure, one of said lead-in conductors being connected with said anode on one side of saidsmo'nd portion, another of said lead-in conductors being connected with said cathode and located on the opposite side of said second portion.

8. A high frequency electric discharge device comprising an anode, a cathode and an elongated grid ii crposed therebetween, electric shield means connected at re on 0* site ends of said grid to provide smooth electrical continuity therewith, and a plurality of conductive connections to said shield means and arranged in parailel whereby the net inductance thereof is minimized.

9. A high frequency electric discharge device comprising anlanode, a cathode, and an elongated grid interposed therebetween, electric shield means connected to at least two longitudinally spaced points on d grid, and a plurality of lead-in conductive connect is to said shield means.

References Cited in the tile of this patent UNITED STATES PATENTS