US2088493A - Cathode ray tube - Google Patents

Description

July 2"], 1937 UTHERLlN ET AL Filed June 21, 1935 INVENTORS. lee bf/zerl/n one fiberfJ/f r 7 f WITNESSES W NEY V Pllellted 1937' PATENT 2,oss,49

oi-"Fics 4 cs'rnons BAY Lee suissiis. Albert 1. assoih.

Pittsburghla aoorporation Application June 21,. ms, 'sss'isi n tissue Our inventio npertains to and more particularly to tubes of the type suitable for oscillographic circuit analysis as by ob serving or photographicail-y the-wave s shapes of varying current 'or voltage quantities. Cathode-ray tubes, in general; comprise means for generating a-stream of electrons which is projected as a small spot;upon a-"fluorescent screen. By passing the 10 through either an electrostatic neld, or a magneticfleld. issw'erved'fromitsstraight" path and-traces a pattern or wave onthescreen control voltage which which corresponds to the creates ileid.

already beenmade'in industrial routine testing,

but'the' tubes' previously available could not be uniformly assembled; did not have uniform charthe - It is accordingly an object oi our invention 4 to provide cathode-ray tubes having uniformly improved characteristics. v

A further object of our-invention is to provide cathode-ray tubes wherein the component parts may be assembled and with uniform Legumy to insure. improved iocusingchsractercm It isalso an A further object ofour invention is to pro- .streamofelectrons.

' vide means for. of sharply defined The inventionitself, both'as'to'its;

49 thereof, will hest'be understood the'followin: a specific when in conjunction its-ms;

iis a.

the integral membly the elements.

ofthetubewhich ismountedasaunltonthe stream of v electrons "Numerous applications of suchtubes have 'viswsslonsit s'iodsiaxis of' -a tube 1o (cum-21.5)

cathode-ray tubes, B- l s-a similar view .sliowingthebly turned ninety degrees; V

Fig. dis a top plan view of the assembly; Fig; 'iis a detail view showing the electron source; and,

Fig. 8 'isa detail vi'ewshowing s section taken axially through the electron gun which projects theelectronstream.

Referring more specifically to Fig." 1' of the drawing, our cathode-ray tubeico'mprises a glass container i, which enclosesand supports ,the various elements. The vessel is preferably ,of an inverted conical formationhaving a tubuhr portion extending from the apex theerof. The base to! the conical portion is preferably convex and the interior surface is provided with a fluorescent screen 3 which may, for example. consist of a coating of willemite, a crystalline substance containing zinc, which becomes a vivid green when struck by a stream ot'electrons. Inorder to drain oil the electrons, the screen is made slightly conducting and is in contact with the second or high speed accelerating anodewhich comprises a silver coating 4 provided on. the inner surfaces of the side walls of the conical portion. A terminal 5 extending from the, side of the conical portion aiiords convenient connection' to this high speed or. second anode. It is to, -be understood. how-' n ever, that the principles of our invention are object'oi' -our invention to. pro .v

vide a cathode-ray tube wherein the component elements as a rigid unit upon one- "vessel is provided with a contact plug 0 to es-.

' 'tablishelectrical connection through a conventional socket (not shown) to various circuits (not 5 shown) from which the tube is to be energised.

' connections as far removed from the other circuitsas possible, and for reason the tube is provided with hollow conduit portions I proie cting. radially from an intermediateportion' of the 1 tube for leading individual conductors into the- Therearefour suchradiallyettended arms, and each isclosed by-a terminal cap 8 to which the timing and test circuits maybe'connected in any suitable manner.

from the owe; end of thetubular por-.

j tionJof-the vessel is a stem or press. ll through which-conductors are extended-from thecontacts in'the contact plug tothe elements within the tube'.- All electronemitter II, described in deton hereafteL-is supported on a-p'in .ll which is into the press. A control electrode ll ,'which comprises an inverted-cup having-an o sm intne iottom moi-soil; is also mount d 'trol electrode i4 is a cylindrical accelerating with the opening directly above the electron source l2. By applying suitable potentials on this electrode the electron emission from the source I2 may be accurately controlled.

The remainder of the tube elements are assembled together into a unit which is supported by three pins 2| welded or soldered to. a 'flexible metallic bandv 22 which is'clamped around the stem II by a bolt or screw 23. The unitary assembly is more clearly shown in Figs. 4 and 5,-in which the latter shows anenlarged side elevatlonal view of theassembly from the same position as Fig. 1, and Fig. 4 shows how the structure appears when turned ninety degrees on its axis.

Directly above the electron emitter l2 and conanode 24 forqaccelerating the electrons discharged from the electron emitter i2 and projecting them as a sharply defined stream. This device comprises a closed cylindrical member having at least one partition wall or diaphragm 21 intermediate its two end diaphragms 26 and 28, as'shown mor clearly in Fig. 8. x I

A small hole is provided in each diaphragm in series alignment ,whereby the emitted. electrons sion of secondary electrons, some of which pass through the opening of the second diaphragm 21 at a wide angle. The third diaphragm 28,. however, almost completely eliminates the secondaryelectrons which have not passed through the holes in both the first and the second diaphragms.

By mounting a smaller cylindrical member 29 on the last diaphragm 28. any stray electrons emerging from the third orifice willbe collected.

tural unit suitably spacing the deflectingplates If desired, a greater number or diaphragmsthan three may be provided. The electron gun is supported by the three external brackets 2| welded or soldered to suitableflnsll on theouter walls of the gun and extending down and-secured to the flexible stem I I.

Directly above the electron gun 24, in axial alignment therewith, acylindrical member II 8 oi the same diameter is mounted in spaced, insulated relation. The cylinder serves the purpose oi'an" electrostatic shield and also as a structural member rendering possible the rigid union of the various elements of the tube. It is rigidly supfportedin' suitable spaced relation from the-electron-gun, by three externally disposed'bracket arms 24 extending upwardly .irom the electron gun 24 and-spaced ence. Eachbracket arm consists of two angu-' equally around the circumferlar metallic members ll having their adjacent pair'oideflectingplates ends sealed insglsss insulstorbead II and their 1 diverging ends secured to the cylinders, as clearly shown by the' sectional view 0! one such insulating bracket in 1 18.14. Bymaking the insulated able M13211! relation by tour bracket members. oneoi brschet members and to hold them in rigidly spaced parallel relations oi the vessel for cbnnection to the terminal band 22 which is clamped'on the" v charges to accumulate on the glass beads. Such contribution to the successful operation oisuch that where a series of diaphragms, cylinders or ;the like are used, through which an electron A 2,088,498 On pinsli supported in the press and is positioned 44 provides direct conductive connection between the cylindrical shield member 22 and its associated deflecting plate 42, and prevents-the accumulation of electric charges. The other. three bracket arms supporting and joining'theplates are provided with the glass insulating beads. The insulating glass beads adjacent the par- 7 allel edges of the-plates 4i and 42 are quadrumanous, having a formation somewhat similar to a four leaf clover, for securing the ends of four metallic bracket members, two of which 46, ex-

tend laterally to be secured to the adjacent plates,

one of which 41, extends downwardly from each bead to be secured to diametrically opposite points on the cylindrical shield member 33, and 15 the fourth of which 48, extends upwardly from each of the quadrumanous beads to be secured to a second pair of deflecting plates 5| and 52. It

. will be apparent that the arrangement of the quadrumanous beads 45 serves not only to rigidly support and insulate the plates, but also to hold. them rigidly in proper spaced relation.

The second pair of deflecting plates 5| and'52 comprise the uppermost elements of the assembly,

tion, a pair 01 insulating bracket arms 53 are provided, one of which is' connected across. each oithe. adjacent opposed edges of the plates. To hold the upper pair of plates in rigidly aligned relation above the first pair of plates, additional insulating bracket arms 54, e secured between the upper and the lower plates, in offset relation to the arms 48 projecting upwardly fromthe quadrumanous beads 45, thereby providing a four point support and shading a bracing structure to prevent lateral flexing oi the latter.' A flexible conductor il'is attached .to each one of the defleeting plates ,and is' adapted to be extended through the corresponding lateral conduit pot- 40 caps when assembled. i Y

The cylindrical shield member not only serves a very important function as a rigid strucaway from the first anode 24 without the necessi ty of using long flexible bracket arms, but it also serves a very important function asan electrostatic shield. In the operation of the cathoderay tube, the electron emission causes electric charges set up strong 'electrostatic.-flelds which deflect theelectronstream 'i'rom' its straight course it it is unshielded. The cylindrical member "shields the beam in itspath between the flrstanode 24 and the first pair oi. plates 4i, andv 42 and causes the tube to function properly. a

The' union of the various elements Jo! the. cathode-ray tube into a rigid assembly'having; predetermined spacedrelation is a very important.

'adevice. This is true not only because oi the importance or maintaining the accurate alignment or the various elements and the electron stream therethrough, but also'because or the fact stream passes. such elements act similar to lenses in optics and must be properly adjusted with respect to distance,.dimensions'and voltage in order to give the best light and the sharpest definition onthescreen.

a small cylinder'on the anode having alengtlr and 7 ieschsetwe respaceds'sotaninch. Thecontrol applicable to all cathode-ray tubes iargeaand I Y .electrostdticflelds set upby accumulated'elec- Accurate 'trical charges on said insulators.

. manner. and

loosen a from which god's stream electrode comprised an inverted cup it'inch'in diameter, 99 inch long. with admin .088 inch in diameter and spaced.030 inch from the anode. "lihe cylindrical-shield, the anodeand the sets oi 'plateswerespacedaxiallyby iioianinch The dimensions and spacings above set forth are given merely for an example oi a'structure which is satisfactory ior a specific set of conditions and is not to be construed as imposing 1imitations, since the desirable features of our invention are fle ti s p a and sup ported-on the. walls oi the glass enclosin'e'is-very di'flicult to obtain and is not permanent. In the cathode-ray tube constructed in accordance with curinventionythese elements flrst properly spaced and united on the press before it is in'-. serted in-the'vesscl. instead of attempting to properly align and space the elements as the is insert'edand sealed into the vessel: The

press arrangement and oi the elements 0!. the tube is much more accurately obtained in this that its characteristics are not aflected by moderate shocks and vibrations.

As-shown in Pig. '1, the electron emitter may be oi the electrically heated type comprisin'ga heater 1 ll piflnetungstenwiretoiledaboutthroufiha plurality of holes extending axially in 'spaced parallel relationmagnesium oxide enclosed within a metallic nickel heater shell I is closed at the upper end and-is provided with an'insulator 04 adjacent theinnei" suriace and with. a suitable electron emitting substance I onthe upper suriace.

extend to eorrespondingeontact prongs in the control'plug 8; Two of the conductors are con.-

nootedtotheheatertlintheelectronemittena third is com: I nested to ductor is connected to .24. 4 I

- In operation a suitable positive potential isap-' plied tothe flrst anode I4 to cause it to project I oi'electrons. A much higherpodtive is applied to the second anode compristhe'silvercoating on the inner surface oi the conical portion oi the-vessel to 'acce'leratethe electron streamaiterithasbeendeflectedbythe plates to thereby create a much brighter spot on the screen..as set iorth in Patent No. 1,810,018 of D. E, vHowes. The electron stream is thus proirom the anode at low velocity for great sensitivity. or maximum deflection by the plates, and it is'then accelerated to high speed to In view -oi thehlgh'positive potential. on the secto the shell Ii. a fourth iii-coirt des the con-' the tint accelerating anode ond anodeand the proximity of the deflecting lates thereto it is preiera'ble to' groimd the secent and spacingwhen the.

thetubeso'constructedissorugged.

through a"cyiindri =i. rod if of 1i. is'suitably infill-bed. The;

and

ot-the stem ll iive conductors electron stream'irom the deflecting influeneeoi source,

produce a bright sharp trace on-the i any suitable manner. since the .eiseints to be are not usually very'well' means for andthe extended'axis may be readily have shown and described certain oi our invention. wearetuily aware that manymodiflcationsthereoi arepossible.

Our invention, therefore. is not to be'restricted 6 except-insofar. as is necessitated by the prior a ahd'thescope'oi' the appended claims.

We claim as our invention: I

l. l'i unitary assembly for a cathode-ray tube comprising an ing plates, an ectrostatic shield about the elee between said anode and plates and means for rigidly supporting saldiplates on said anode comprising said electrostatic shield and spaced relation to saidjnsulators to protect the electron stream from the deil fl i influence-oi crating anode. sets of deflect- .insuisiors. said electrostatic shield disposed in A unitaryi-ass'emblyior a cathode-raytube lation from said iirst plates andspaced' about the extended axis, of said anode.

:3. A cathode-.ray'tube prising an electron emitter. an accelerating anode for accelerating and projecting an electron stream thereirom, sets of deflecting plates, an

means (or rigidly: supporting said sets oi plates onsaid anode comprising said electrostatic shield insulators, said electrostatic shield being in- .relation to said insulatorsin protect the tic shieldabout the electron path between said anode and plates,

electrostatic flelds set up 'by'electrlc charges on said insulators. an evacuated vessel, a stem theresourceQ'a control electrode, an. anode; deflecting p1ates. .means ior rigidly'securing said electron control electrode, anode. and plates together in spaced porting said electrode source on said stem. hollow arms projecting radially froman intermediate securingsaid plates in-insulated relainspace relation to the anode thereof. a metallic member connected between oneoi saidplatesandtheshield to and condi'iotive con.-

tion on said shield stem. '4. A cathodeeraytube comprising an electron insulated relation. an evacuated 5 vessel for enclosing and supporting said elements. astem extendinginto said vessel. means for supnectton ith'erebetween, a secondv pair of spaced parallel plates disposed at right angles to the plane oi said'flr'st plates, external means for securing said second pair of plates in insulated spaced relation from said first plates andspaced aboutthec extended axis of said anode, andan evacuated vessel for enclosing and supporting said elements. 1 i 6. A cathod'e-raytu'be comprising an evacuated vesse1,-a stem extending thereinto, a unitary structure supported on said stem comprising an electron emitter, a control electrode, an accelerstream of electrons therefrom, sets of deflecting plates, an evacuated vessel, a stem therein, meansfor rigidly supporting and insulating said electron emitter, control'electrode, accelerating anode and plates as a rigid unit on said steam, a fluo-'- rescent screen on the opposite end of said vessel, a conductive surface on the walls of said vessel adjacent tosaid screen comprising "a second high mosaics I speed accelerating anode, and ai terminal conductively connected thereto.) l

8. A cathode ray tube comprising a container having a cathode, a control electrode, a first anode, deflecting plates, another anode and an electrostatic shield surrounding the electron discharge path intermediate said iirst anode and said deflecting plates.

9. A cathode rag tube comprising a container having a cathode, a control electrode, deflecting platm, an anode and a cylindrical member insulated from said anode intermediate said control electrode and said deflecting plates and a direct connection from said cylindrical member to one of said plates.

10. A cathode'ray tube comprising a container structure adjacent thereto restricting the path of the electrons issuing. from said cathode, a cylindrical conductingmember surrounding the electron path, an anode, deflecting plates intermediate said cylindrical conducting member and said anode and a direct connection between one 01 said plates and said cylindrical member.

LEE SU'I'HERIM; AIL-BERT. .7. HARCHER.

. DIQQL'AIMSR I mesa-493.4 sumac, Wilkinsburg, and AzufiJ. Harchcr, Homestead, Pa.-

Oa'r'nonn R'Ar "Tuna.

Patent dated July 27, 1937-. Disclaimer filed v November 15', 1939.,fby theasaignee, Westinghouse d: Manufacturing Company.

S enters claims the patent Gama B uib" 5, 1939.1

having a cathode, a control electrode, a separate nectton ith'erebetween, a secondv pair of spaced parallel plates disposed at right angles to the plane oi said'flr'st plates, external means for securing said second pair of plates in insulated spaced relation from said first plates andspaced aboutthec extended axis of said anode, andan evacuated vessel for enclosing and supporting said elements. 1 i 6. A cathod'e-raytu'be comprising an evacuated vesse1,-a stem extending thereinto, a unitary structure supported on said stem comprising an electron emitter, a control electrode, an accelerstream of electrons therefrom, sets of deflecting plates, an evacuated vessel, a stem therein, meansfor rigidly supporting and insulating said electron emitter, control'electrode, accelerating anode and plates as a rigid unit on said steam, a fluo-'- rescent screen on the opposite end of said vessel, a conductive surface on the walls of said vessel adjacent tosaid screen comprising "a second high mosaics I speed accelerating anode, and ai terminal conductively connected thereto.) l

8. A cathode ray tube comprising a container having a cathode, a control electrode, a first anode, deflecting plates, another anode and an electrostatic shield surrounding the electron discharge path intermediate said iirst anode and said deflecting plates.

9. A cathode rag tube comprising a container having a cathode, a control electrode, deflecting platm, an anode and a cylindrical member insulated from said anode intermediate said control electrode and said deflecting plates and a direct connection from said cylindrical member to one of said plates.

10. A cathode'ray tube comprising a container structure adjacent thereto restricting the path of the electrons issuing. from said cathode, a cylindrical conductingmember surrounding the electron path, an anode, deflecting plates intermediate said cylindrical conducting member and said anode and a direct connection between one 01 said plates and said cylindrical member.

LEE SU'I'HERIM; AIL-BERT. .7. HARCHER.

. DIQQL'AIMSR I mesa-493.4 sumac, Wilkinsburg, and AzufiJ. Harchcr, Homestead, Pa.-

Oa'r'nonn R'Ar "Tuna.

Patent dated July 27, 1937-. Disclaimer filed v November 15', 1939.,fby theasaignee, Westinghouse d: Manufacturing Company.

S enters claims the patent Gama B uib" 5, 1939.1

having a cathode, a control electrode, a separate

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