US2783408A - Electric discharge tubes - Google Patents

Description

Feb. 26, 1957 D. J. WILLIAMS ET AL 2,783,408

ELECTRIC DISCHARGE TUBES Filed April l, 1953 3 Sheets-Sheet 1 Inventors: DAVID Tour! wlw/Ams AHV Kfwmono CLJFFMD Baco# Feb. 26, 1957 Filed April 1, 1953 D. J. WILLIAMS ET AL ELECTRIC DISCHARGE TUBES 5 Sheets-Sheet 2 Inventors: OAvr Taf-n1 WILLI/4ms M0 mmc/1D CLIFFORD BMO Feb. 26, 1957 D. J. WILLIAMS ETAL 2,783,408

Y ELECTRIC DISCHARGE TUBES Filed April 1, 1953 3 Sheets-Sheet 3 54 Inventor DAVID IIo h//LL/H'rs NW @www FFoKD BAM/7 www ELECTRIC DISCHARGE TUBES David John Williams, Nottingham, Raymond ,C liiord Bacon, Wollaton, Nottingham, and John lReginald Acton, Bunny, England, assignors to Ericsson \'I`,elephones Limited Application April 1, 1953, Serial 3746,!l7'il 3 Claims. (Cl. S13-109.5)

Our invention relates to electric discharge tubes and particularly to gaseous discharge tubes used .forthe purpose of displaying an illuminated character or symbol.

ln known forms of discharge tube .used for display purposes the electrode invested by the discharge -glowgis so shaped that the said glow exhibits the characteristics of a particular alphabetical letter, numerical digit, or

other symbol. A plurality of such tubesmay. be arranged Y in a certain order to display an illuminated message or other signal, and by means of changing the relative position of some or all of the constituent letters and/or digits a variety ot such messages may bedisplayed. The message displayed by any one arrangement of suchvtvubes,

however, cannot be changed rapidly to a dissimilarmes- Y sage because of the necessity to rearrange :the `positions of the constituent tubes each with its individualletter or digit.

Itis an object of our invention to provide mea-ns whereby each of a plurality of symbols particular to an electric the present invention;

'Fig. 2,is Ya perspective View, from below, of'the tube of-Fig. l;

Fig. 3 Vis a diagrammatic view of the different digits available with the tube shown inFigs. land 12;

Fig. 4 is a partial plan view of a modification of the tubeshownin Figs. l and 2; g

Fig. 5 is a ,perspective lview Vof a second embodiment offthedischarge tube according tothe present invention; and

Figf is a perspective view cfa portion of the tube shown in -Fi-g.15, partially in section.

'ln the discharge t-ube-,embodyinggour invention ydepicted in Figures l and 21V/e include -Ywithin an airtight glass bulb '11, -'lled with a gaseous mixture of substantially `99.5%neon and 055% argon to vapressure lequal to some 40 millimetres of mercury, anl -electroder'assemblyf formed from -a-pluralitylof electrodes 1, 2, '3,4, 15,. 6, v7, '8a and i 8b each of -ilat --nickel -wire 1*.07 millimetres wide Vand attached to -afmica disclt). `Each such electrode is fastened to mica disc10byc-lenching both ends thereof which are arranged to Apass through holes `to the rear` of the saiddisc 1i?. Electrodes18a andl 8b are connected together within the bulb and provided with acornmon lead-out Wire, each other electrode 1 to7 inclusivevis provided with an'individualleadout wire. All the `said Ylead-nut wiresrass vby Way. 0f thefflat pinch 11.3' 11o-.the tubular foot 14 of the bulb, through'in'dividual insulating 2,783,408 .Patented .Feb 25 1.957

.2 v tubes therein to individual `connecting pins 15 which project through the bottom Vof a base 12 of known type. Fused to the flat pinch 13 of foot 14 is a nickel-wire trame 9 to Wcarry the getter. The portion of ,each electrode at the rear of vdisc 10, and that portion of each lead-out wire between the electrode and pinch 1-3 is covered with alumina which iis .applied when suspended in a Suitable painting medium.

When viewed from the iront of the discharge tube the .positionof each electrode 1., 2, 3, 4, 45., -6, 7, V8a and 8b in the electrode `assern'blyis such that when certain of the said electrodes are connected to the negative pole, and Vone or more of the other ,electrodes are connected by way or 47,000 ohm resistorto the positive pole of .a direct current 200 volts supply a discharge glow will investthe electrodes connected to thepegative pole of the supply. The shape of each yelectrode 1f, l2, 3, 4, 5, 6, 7,8[1 and 3b is such-as to resemble a constituent rpart of one `orfmore numerical digits, and `their dispositionis such that the contigui-ation of thedischar-ge glow emanat` ing `from the negatively connected electrodes is caused to resemble the particular digit which-it is desired to display The discharge tube described and illustrated with lreference to Figures l and 2ris designed to display each of the digits 1, 2, 3, 45, 6, 7, 8, 9, .and 0 separately, and theparticular combination of illuminated negatively connected cathodes and non-illuminated positively Vconnested anodes for `each of the saiddigits is indicated by symbols A, AB, C, D, E, F, fG, H, J, and K respectively in Figure 3. In the s aidlsyrnbols A to K inclusive the outline of the illuminated electrodes is shown in full, and that of the non-illuminated electrodes in broken line. Electrodes 8a and 8b form the anode electrodes when a digit l, 2, 3, 5, 6, 8, 9, or 0 is displayed, and electrode 5 forms the anode when a digit 4 or 7 is displayed. The reference numbers of the individual electrodes in symbols A tol( inclusive of Figure 3 have not been included but will be readily understood by reference .to Figure 1.

Figure 4 indicates the electrode assembly of a similar type of discharge tube as ldescribed with reference to Figures `l and 2, and as `seen from the front of the tube. The electrode assembly shown in Figure 4 is designed to display individually any of a plurality of symbols each indicative of a particular numerical ligure or alphabetical character. The design of the discharge tube of which Figure 4 forms a part closely resembles the discharge tube described with reference to Figures l and 2, in which ya plurality of electrodes of nickel Wire or tape are fastened byl clenching or other suitable means to the face of an insulating discof mica. or other suitable material, and electrode connections are extended from the rear of the disc on ywhich they are mounted, by way of lead-out wires passing through the pinch and foot ofthe tube, to connecting pins in the base of the tube, and thence in known manner to external circuiting means. Such an electrode assembly as shown in Figure 4 may be mounted for convenience `on a mica disc 16 some 28.5 millimetres in diameter, and enclosedwithin a glass bulb 65.0 millimetres in length filled With the described gaseous mixture of neon and argon to a pressure. equivalent to 40.0 millimetres of mercury. j

A discharge Vtube constructed in the manner described lwill display by illumination a selected symbol, in the form of `an alphabetical character or a numerical ligure, when a potential of the order of 200 volts, derived from a suitable direct current source, is applied to a combinationof electrodes particular to the selected symbol. A plurality of such, diiferentcombinations of electrodes each particular to .onerofv the 26 letters of the English alphabet,

,and/orto, one ofthe/ten numerical digits in `therangie 1 to 9 andO inclusive,rfor use with a discharge tube having an electrode assembly as depicted in Figure 4 is given below in tabulated form. In the following table each electrode to be connected to the positive pole of the supply by way of a 47,000 ohm resistor is marked A, each elec trode to be connected to the negative pole of the supply -is marked C, and each disconnected electrode is marked thus:

4 are formed are suitably spaced from each other and project from ilat pinch 57 -in a substantially straight row. A small glass tube threaded on the stem Wire 501 of electrode 50 is fused to thc pinch S7 of the bulb 55, at ya point where the said stem 561 emerges from the pinch 57. The surface of each stem wire and electrode 41 to 50 from the discharge surface of the electrode -to the pinch the destrabar@ ,to ,50

' Reference number of electrodes shown in Figure 4 Symbol displayed 2122 23 24 25 262728 29 so 31 32 33 34 35 a6 373s -oG-A--- coAoooo -c-no---o---o-o -ACOCCCG- -C-oA--o--ooo --0oo-A---G---ooo 0AC---C-- --GCo-A-C--C---ooo -o-G-Ao-C-ooo --GoCA-C-o--C` --CoC-A-o--oe---oo -Cooo-A-o--o---GCO -ooO-A--C -CCCG-AG-C-o -CoCA---oo GCC-AC --ooo-Ae---O---o-C -GC-A-o--C--oo -oo-A---- ------A-G--C---C Co--Ao---o-C --oC--A---G -oo-oAoo--C --oo-oA-C--oo --Coo-A-C--o---o --Coo-A-o--CC --oCo-A-C-GC---o --ooo-A-C--ooo -C-C-A-o-oo0 o0oA --Co--o--G-oA- CooA G---C--CCA. --oooo-A -o-o---o-A- ---0--o-GGA Thus in each of the discharge tubes described with 57 of foot 58 is insulated by means of a at plate S4, a reference to Figures l, 2, 3, and 4 the shape, dlsposl- 40 mica disc 53, andastudded'plate SZ. Plates 52 and 54 are lion, and Plllfally of the electrodos hel'olll alo oooh formed from a suitable ceramic material, and are suitably allaflged l0 be Slloh llla any s ylllbol of a 'Plllfaly 0f perforated and grooved to accommodate the said elecdlffofoll Symbols 1S displayed llldlyldllally by 'f1 Smgle trodes 40 to 50 and their stem wires, as shown, for extube when a suitable negative potential is extended to a ample, by items 471, 451 :and S01, The lower surface Selected plurality of electrodos and a Suitable posgtlvo po- 45 of plate 54 is provided with a relatively wide channel tentlal J'S Extended t0 011 O1 m01' of the ellallllllg eleowhich is of such a size that it tits upon the upper surface rOCleS 1D the tube The Sold Pos1-flye and Ilegaflvo Roof pinch 57, and the glass tube which surrounds stem wire eDfllS may be @Xlellded to woll 0f tho SeleCod Pllll'ally 501 engages a hole of suitable size in the said plate 54. of electrodes by lioowoolrolutmg moans, for example, The engagement of the said glass tube with plate 54 serves by Way of a mlllfl-Posltloll rotary SWltCh, manually 0P- 50 to maintain it in its proper position on pinch 57, in this elafod koyS, 0r ComblllalOnS of TelayS Mld/of Selector position each stem wire lies opposite an associated hole SWIClleS of the lyPe employed lll telephone @Xchange which passes from side to side through the said plate 54. eqlllpmolv When plate 54 is placed in position upon pinch 57 A Plofolfod. form of dlsollalgo tubo Wllloll embodles the stem wire of the electrodes 41 to 49 are arranged to 0111' u lvollfloll 1S SlloWIl on Figur@ 5 of the aoComPalll/lflg 55 project through a straight row of holes in the plate 54, drawing, and details of the electrode assemblyof such a and they are then turned at right angles into Such posiform of 'mbe are Shown on Flgue .6' Infthls an? of tions that they lay in a plurality of grooves in the face lube eaoh electfode 41 to 49 me, SWE 1S Orme rom of plate S4 which adjoins mica disc 53. At suitable points round nickel wire, and forms an integral part of a stem in the Said grooves the Said stem Wires are turned up WHC tvlllfh lflsl wsthn att Pmch. 57m? tfosrlg 60 wards at right angles and each passes through an assozf con salflli' fcn 'o toie ilrgvlgnd hive a nickel ci-ated hole in mica disc S3 and in the topmost plate 52. rlm O'C .elf 'p s l The position of the plurality of holes in plate 52 is such wire part within bulb 55, and a belated-copper part wlnch that each asses thro h one of a Iurality of Studs 60 passes through pinch 57 to the interior of foot 58. The h. h ct f m th gu f 1 t 52 d form part of each stem wire within foot 58 is enclosed by a 65 vnuteprre arotheref pp lie Ooitavher ae e1ec suitable insulating sleeve 59, and is attached at lts lower tr d g1 t p49 e l t Q52 th are t med at end to one of a plurality of connecting pins 61 in base ,0h65 o dlnlefg fom P ef .YI 12 h 60. Each electrode 41 to 49 forms a cathode electrode ng tlangles 'im endpass vlrt el ace o p at w ee whilst electrode 50 forms an anode electrode which is they are agam mme al 1.1% lalg .es o Owgvar common to all of the said cathodes. Anodc electrode 50 through a secon assomme o e m o 1 p ates au which is fastened in foot 58 in a similar way to cathode o 54- The free end 0f eacll Such electrode 4 to 493 emerges electrodes 41 and 49, is formed from heavier gauge 9D libe grooved under 51de of plate s4 .Where It 1s bent Vcomposite wire than .the said cathode electrodes 41 to at llght ongles 'and fastened by clenchmg tf Plate 54' 49,` and has an atm of nickel wire fastened to the main The location of the Sald holes, and grooves m plateSSZ member to forma nickel electrode of cruciform shape. and 54 is such that the exposed surfaces of the wires "'IfhtrstemV wires from which 75 which form the discharge surfaces of cathode electrodes c 41 to 49 are caused to assume the shape of a constituent part of one or more numerical digits.

When constructed in the described manner the discharge surface of each of electrodes 41 to 49 lies in substantially the same plane, The stem wire of anode kelectrode 50 passes through the glass tube, which is fastened to pinch 57 and is located within a hole in plate 54, and thence through mica disc S3 and a hole in plate 52. At the point where yanode electrode 50 emerges from plate 52 it is turned at right angles to lie in a plane substantially parallel to and below the plane in which electrodes 41 to 49 are located. The main member of electrode 50 lies parallel to electrodes 43, 44, 4S and 49. The disposition of the described electrode assembly is such that when a suitable negative potential is connected to a selected combination of electrodes 41 to 49, and a suitable positive potential is applied to electrode 50, the configuration of the discharge glow, which emanates from the negatively -connected electrodes, resembles a particular se lected numerical digit'.

The dimensions and operating characteristics of a discharge tube constructed in the manner described with reference to Figures 5 and 6 are given below, such a tube has been manufactured and given satisfactory service. Glass bulb S5 is formed from fa domed glass cylindrical tube some 150 millimetres long with an internal diameter of some 32.5 millimetres. Within the open end of such a tube is fused the glass foot 58, in the flat pinch 57 of which is arranged the plurality of electrode stem Wires spaced a uniform distance apart. The round ceramic plate 54 which adjoins pinch 57 is substantially 30.0 millimetres in diameter, and some 5.5 millimetres thick. The straight row of holes which abuts on to pinch 57 passes through the centre of plate 54; each such hole is approximately 1.0 millimetre in ydiameter and is centered some 2.0 millimetres from each adjoining hole. Mica disc 53 is formed from mica sheet substantially 19.0 millimetres thick, iandhas a minimum diameter of 31.6 millimetres, and a maximum diameter of 33.0 millimetres, measured from the top of the projections on the periphery of the disc. The holes through which the stem wire electrodes 41 to 49 pass may conveniently be formed by a small plurality of cut-outs of suitable circular or ellipsoidal shape or a greater plurality of separate small holes for the passage of an individual electrode may be provided.

The topmost ceramic plate 52 is formed from unglazed ceramic material similar to plate 54 `and has a similar diameter. The base of plate 52 is some 3.0 millimetres thick, and studs 60 are raised some 4,0 millimetres above it, whilst stud 61 through which anode electrode 50 passes is raised some 2.5 millimetres above the said base. When the cathode electrodes 41 to 49 are formed from nickel wire some 0.4 millimetre in diameter, and the anode electrode 50 from similar material some 0.8 millimetre thick, the diameter of the holes in plate 52 through which the said anode electrodes pass is of the order of 0.5 millimetre in diameter, the hole through which the anode electrode 50 passes is approximately 1.0 millimetre in diameter.

When such a tube is exhausted in known manner, and lled with a gaseous mixture comprising some 99.5% neon, and some 0.5% argon a discharge glow indicative of a numerical iigure is produced when the anode electrode 50 is connected to the negative pole, and at least one cathode electrode is connected by way of a 47,000 ohm resistor to the positive pole of 'a direct current 200 volts supply.

Although our invention has been described with reference to tubes 'displaying numerical digits and alphabetical characters we do not conne ourselves to such symbols and in other tubes embodying our invention symbols of other kinds may be employed, for example, conventional arrow symbols indicative of direction. ln other forms of tube embodying our invention we may employ electrodes formed in other ways of diiferent material than the. nickel wire 4and'tape used in the described tubes, for example, electrodes of conducting material may be painted or deposited by other known means on aplate or disc of mica or other insulating material.

A plurality otdischarge tubes embodying our invention .may be arranged in rows and/ or columns, and adapted to display a plurality of different'messages or other .signals in rapid succession by employing means whereby a condition is extended to illuminate a. selected electrode indicative of a particular letter or digit in some or all of the plurality of discharge tubes. The order in which the selected electrodes are |arranged in the said rows and/ or columns is such as to provide an illuminated display indicative of a particular message. Such a message can be changed rapidly by switching the illuminating condition to another selected electrode in some or all of the discharge tubes forming adisplay.

What we claim is:

l. A gaseous electric glow discharge device comprising a tubular envelope having alight transmitting wall at one end and a pinch at its opposite end, an insulating mounting plate formed with electrode supporting apertures and disposed within the envelope substantially normal to the longitudinal axis thereof in the neighbourhood of its light transmitting end wall `and shaped to conform to and substanti-ally till the internal cross-section of the envelope, a plurality of electrodes each with its ends bent over and positioned in appropriate apertures in sai-d mounting plate, said electrodes having glow-producing portion-s all lying in a common plane adjacent to that face of the mounting plate which is towards said light transmiting end wall and having their ends clenched against the opposite face of the mounting plate, the glow-producing portions yof said electrodes being shaped and disposed to adapt them by selective energis'ation to display alternatively a plurality of different illuminated symbols, and individual connections extending from ends of said electrodes directly away from the face of the supporting plate and through said pinch to the exterior of the envelope and serving to position the mounting plate in relating to such pinch.

2. A gaseous electric glow discharge device comprising` a tubular envelope having a light transmitting Wall at one end and having a pinch from which an electrode assembly can be supported, an insulating mounting plate formed l with electrode supporting apertures and disposed across the interior of the envelope in the neighbourhood ot its said end wall andshaped to conform to and substantially lill the internal cross section of the envelopes, a plurality of electrodeseach having its ends bent over and extending through appropriate apertures in said mounting plate and clenched thereagainst, said electrodes having glowproducing portions yadjacent to that face of the mounting plate which is towards said end wall and lying in a common plane substantially normal to the longitudinal axis of the envelope, fand being shaped and disposed to form between them the component parts of a plurality of different symbols and individual connections extending from ends of said electrodes away from the plane of the mounting plate towards and through said pinch to the exterior of the envelope and serving as a sole means of supporting the mounting plate from the pinch.

3. A gaseous electric glow discharge device comprising a tubular envelope having an end wall pervious to light, a pinch for passage of connections at its opposite end, an insulating mounting plate perforated to form velectrode supporting apertures and disposed across the interior of the envelope in the neighbourhood of its first said end and shaped to conform to the internal face of the envelope, a plurality of electrodes each having its end portions offset and reaching through appropriate ones of the apertures in said mountingplate and clenched against the further face thereof so 'as kto hold intermediate portions of the electrodes exposed to the first said end of the envelope, said intermediate portions of the electrodes lying in a common plane substantially normal to the longitudinal axis of the envelope and being shaped andrdisposed to formcmfnf ponent parts of symbols and "adapt them'by selective .energisat-ion to display alternativelya pliir'ality 'of dif ferent illuminated symbols and individual electrical connections extending through said pinch and connected each to an associated electrode and projecting through an aperture in the mounting plate.

References Cited in the le of this patent UNITED STATES PATENTS Boswau Jan. 3, 1939 Metcalf Nov. 18, 1952 VHancock Nov. 18, 1952 Hancock Feb. 14, 1956

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