US2170663A

US2170663A - Electron discharge device

Info

Publication number: US2170663A
Application number: US13854A
Authority: US
Inventors: William H Painter
Original assignee: RCA Corp
Current assignee: RCA Corp
Priority date: 1935-03-30
Filing date: 1935-03-30
Publication date: 1939-08-22
Anticipated expiration: 1956-08-22
Also published as: USB388112I5

Description

Aug. 22, 1939. w. H. PAINTER 2,170,633-

BLECTRON DIS CHARGE DEVICE Filed March 30 1935 2 Sheets- Sheet 1 INVENTOR WILLIAM H. INTER BY 7 AT'TRNEY Aug. 22, 1939. w. H. PAINTER 3 ELECTRON DISCHARGE DEVICE Filed March 30, 1935 2 Sheets-Sheet 2 5. II III I INVENTOR WILLIAM H. PAINTER Patented Aug. 22, 1939 UNITED STATES PATENT OFFICE ELECTRON DISCHARGE DEVICE tion of Delaware Application March 30, 1935, Serial No. 13,854

5 Claims.

My present invention relates in general to an improvement in electronic .tube structure and more particularly relates to the mounting of electron beam generating, focusing, and accelerating electrodes within an electronic device of the cathode ray type. It has been customary in the past to provide in an electron tube of the cathode ray type a structure of electrode elements within the tube by mounting certain of the elements comprising the electron gun upon a reentrant stem. To provide electrical contact with these elements lead wires and spuds were provided in the glass press and the elements were individually and separately attached to these lead wires by welding or other suitable means. The resultant structure had the disadvantage that the electrode members were in many instances non-rigidly supported and that relative motion was possible between the various elements It is well known in the cathode ray art that accuracy of alignment and spacing of the various tube parts is a prerequisite to efficient operation and that such alignment and spacing has been exceedingly difficult to obtain by the conventional means of support.

Therefore, in accordance with my invention, I have provided a cathode ray'device having novel structural features which increase the rigidity of the assembly and thereby improve the operating characteristics of the device. Also, in-accordance with my invention, it is possible to provide close electrode spacings which heretofore were very difiicult to obtain.

Having in mind the defects of prior art tubes, it is an object of my invention to provide improved supporting means for the elements of a cathode ray tube. It is a further object of my invention to provide an electron tube electrode assembly having the component parts concentrically mounted in a predetermined spaced relationship.

My invention possesses numerous other objects and features which will be set forth in the following description of the invention, and, as will become apparent from reading the specification, many modifications and changes in form may be provided so that I do not intend to limit myself to the specific modifications shown, but believe myself to be entitled to adopt variantembodiments of the invention which fall fairly within the spirit and scope of the appended claims.

The novel features that I consider characteristic of my invention together with the invention itself will best be understood from the following description of certain preferred embodiments thereof when read in connection with the accompanying drawings in which,

Figure 1 is a View of a cathode ray tube in side elevation embodying one modification of my invention;

Figure 2 is an axial sectional View of one modification of my invention; and,

Figure 3 is an axial sectional view of a second modification of my invention.

If reference is now made to the drawings it Will be seen that the foregoing and auxiliary objects are attained by providing according toa preferred embodiment of my invention, a concentric electrode assembly unit by the use of suitable insulating spacers so positioned as to hold the electrodes in a single unit assembly. Specifically the oathode, control grid and electron accelerating elements are provided with flanges whereby these elements are rigidly supported by means of insulating compression members. The electrodes are held rigid by the spacers serving as compression members in the assembly and the entire unit is then supported as a whole from the stem press insuring a maximum of rigidity among the component parts.

Referring now more particularly to the accompanying drawings the cathode ray device comprises the usual sealed and evacuated vessel l0 having a substantially cylindrical neck section I! and a frusto-conical section l4 terminated by a substantially plane surface it. The reentrant stem press it is used to support the electron gun assembly 20. The electron gun assembly, as shown in more detail by Figure 2, comprises the filament or heater 22, a cathode and control grid assembly 24, an accelerating electrode assembly 26 and an anode assembly 28. Suitable support leads 3ll-32, one of which may be a current carrying lead, support the gun assembly from the reentrant stem press.

The sub-assemblies, enumerated above, may have current carrying leads designated as 34, 36, 38, and Ml respectively. The tube Ill, preferably has incorporated therein

beam deflecting plates

42 and 44, which by impressing suitable operating 45 potentials thereon may be made to direct the beam over various portions of the luminescent screen 46 deposited on the inner wall of the end section I6. An auxiliary beam focusing electrode surface 48 is provided on a portion of the inner wall 50 of the vessel terminating in a current carrying lead 50'.

That embodiment of my invention shown in Figure 2, as already considered, comprises the cathode-control grid assembly 24, accelerating 55 electrode assembly 26, and anode assembly 28. It will be seen on reference to the drawing that the cathode-control grid assembly comprises the cylindrical sleeve 52 surrounded by the supporting disc The cathode 23 is provided with an indentation 25 which may contain electron emissive material such as barium or strontium compounds.

The insulating disc 60 is provided with holes 62 thru which may be threaded the filament leads 34 and the cathode lead 36. The cathode is rigidly supported between this disc 60 and'a recessed insulating disc 64. These two insulating members are held by compression between the flanged member 66 and the apertured flanged control grid disc 68. The cathode is thus held securely by compression within a predetermined axial distance of the control grid disc, such distance depending upon the recess in the insulator 64.

The cathode-control grid assembly 24 is rigidly secured to the accelerating grid assembly 26 in much the same manner as the cathode was positioned within the control grid assembly. The annular apertured disc 5 carrying the cathodecontrol grid assembly is positioned and spaced from the apertured flanged disc 10, which forms the effective accelerating electrode surface, by the insulating members 72 and M. These insulators are supported in compression between the flanged members 79 and 18; the entire assembly being retained by the cylindrical sleeve 18.

In like manner the accelerating grid-control grid assemblies are supported by the insulating members 8!] and 82 between the flanged discs 84 and 88 which are supported in turn by the anode assembly 28 comprising the cylindrical sleeve 88 and apertured

discs

90, 92, and 94.

A further embodiment of the structure shown in Figure 2 is that shown in Figure 3 wherein the various component parts have similar designations. The cathode-control grid assembly 24 is for all practical purposes the same as that shown in Figure 2 comprising the heater 22, cathode 23 supported by the insulating spacers 60,

. 64 between the apertured discs 66, 6B and cylindrical sleeve 52. In this modification the entire gun assembly 20 is supported from the stem press l8 by the accelerating electrode assembly 26 through the

supports

30, 32 rather than through the anode assembly 28.

The accelerating electrode assembly thus rigidly fixes the position of the cathode-control grid assembly 2G by insulating members 72, M and the anode assembly by the

insulating members

80, 82. insulating members 72, M, 80, 82 by compression between the

flanged discs

26, 98, IEO, which are fastened to the accelerating electrode cylinder 78 by welding or other suitable means. In this modification (Fig. 3) provision may be made to supply operating potential to the anode 28 through the flexible current carrying lead IM. The entire electron gun assembly 20, as a single unit, may be supported by the stem l8 through the rods 32. The current carrying lead I 04 being This rigidity is insured by holding the.

flexible will furnish no material support for the anode, that element being supported by the aforementioned insulating spacers.

It will be apparent to those skilled in the art that the electron gun assembly may be supported from the stern in a number of ways, such as by rods extending to the control grid assembly rather than to the anode or accelerating electrode assembly.

What I claim is:

1. A cathode ray discharge device comprising an enclosing envelope having a stem, a plurality of rods extending from said stem, an anode mounted on said rods, said anode partially enclosing a cathode, control electrode and accelerating electrode mounted in concentric relation with said anode and supported thereby independently of said stem.

2. A cathode ray discharge device comprising an enclosing envelope having a stem, a plurality of rods extending from said stem, an accelerating electrode mounted on said rods, said accelerating electrode partially enclosing a cathode and a control electrode and an anode mounted in coaxial relation with said accelerating electrode and supported thereby independently of said stem in a position to at least partially house all of said electrodes.

3. A cathode ray device comprising an enclosing envelope having a stem, a plurality of rods extending from said stem, a control electrode mounted on said rods, said control electrode supporting in compression between concentric insulating spacers, and in coaxial relation therewith, a cathode, accelerating electrode and anode, and said anode being positioned at least partially to surround all of said electrodes.

e. A cathode raydevice comprising an enclosing envelope having a stem, a plurality of rods extending from said stem, an anode mounted on said rods, said anode supporting in compression between concentric insulating spacers, and in concentric relation therewith, a cathode, control electrode and an accelerating electrode, said electrode control, accelerating electrode and anode each having apertures located in. alignment with the cathode, said apertures being of different diameters.

5. An electron tube comprising an enclosing envelope having a stem member at one end thereof, a plurality of current carrying support members secured within the stem portion and protruding inwardly of the envelope, a cold electrode member supported rigidly from the inwardly extending support members and a cathode member also positioned within said envelope and at least partially surrounded by the rigidly supported cold electrode, and a plurality of additional cold electrodes rigidly supported from the first named cold electrode independently of the support stem and in concentric relationship with the first named electrode and the cathode, and also at least partially housing said first named electrodes.

WILLIAM H. PAINTER.