US2214441A - Mobile pattern glow discharge device - Google Patents

Description

Sept. 10, 1940. R. H. SEAMAN El AL I 2,214,441

MOBILE PATTERN GLOW DISCHARGE DEVICE ll/Gll fREQUE/VGY Cdr/ A. Jchwenaen;

Sept. 10, 1940.

R. H. SEAMAN El AL 2,214,441

MOBILE PATTERN GLOW DISCHARGE DEVICE File d Nov. 9, 1937 3 Sheets-Sheet 2 I l l W W m n e e 6 W .J/ h 5 A .0 n/ .mw RC u I f L 6 HIGH LOW I fEE uE/Ycr Sept. 1940- R. H. SEAMAN El AL 2,214,441

MOBILE PATTERN GLOW DISCHARGE DEVICE Filed Nov. 9, 1937 3 Sheets-Sheet 3 1 j/GH FREQUENCY 2/ 1 3 rwc/wtou I zowfzzouavcy 22 I F/cbard/i Jed 2m, Car/A. Jc/m/enden.

Patented Sept. 10, 1940 UNITED STATES PATENT OFFICE MOBILE PATTERN GLOW DISCHARGE DEVICEv Application November 9, 1937, Serial No. 173,724

5 Claims.

Our invention relates broadly to glow discharge devices, and more particularly to an electrical circuit arrangement for controlling the discharge in a plurality of tubular structures, progressively and in sequence.

In our copending application, Serial Number 43,742, filed October 5, 1935, for Advertising signs, Patent No. 2,121,829, dated June 28, 1938, we have described novel methods and circuit arrangel ments for producing mobile glow discharge patterns. Our present application concerns improvements therein which are especially applicable to advertising signs of large dimensions. In the course of our experiments it has been found that the oscillating current generator has to be capable of generating high power if the glow discharge is to be formed in a long discharge tube. In the system of our present invention, a low power oscillator is suiilcient as it is required to excite only comparatively short lengths of tubes.

One of the objects of our invention is to provide a display device comprising a plurality of sections of gas filled discharge tubes bent in suitable forms and connected to an electrical network 25 which includes a high frequency and a low frequency source of power, the high frequency source of power being adapted to cause the glow discharge pattern to move in any desired fashion and the low frequency source of power being 30 adapted to susta n the glow for predetermined intervals.

Another object of our invention is to provide a soource of oscillating voltage adapted to cause a glow discharge to form progressively in a tube 35 from one end to the other, in addition thereto a source of low frequency power adapted to sustain the glow discharge while a second glow discharge tube is excited by the oscillating voltage progressively until the full length of the second' 40 tube contains a discharge; thereafter to sustain the glowin the second tube as well as in the first by low frequency power and likewise excite subsequent tubes successively, at first by means of an oscillating voltage of higher frequency until the 45 full tube contains a glow, and then together with all preceding tubes, by low frequency power in order to sustain the glow therein; and thereafter, when the glow in all the tubes has been sustained for a desired time interval by means of low fre- 50 quency power, to either manually or automatically cut off the low frequency power and to repeat the operations as desired.

' A further object of our invention is to cause a mobile glow discharge to form progressively in 65 consecutive sections of a glow discharge device.

by means of an exciting oscillating voltage of higher frequency and a sustaining voltage of either low frequency or direct current.

Still another object of our invention is to divide a glow discharge display into a plurality of sections and to provide means for exciting the sections to form a glow discharge progressively in consecutive sections.

A still further object of our invention is to provide means for forming a glow discharge progressively in a glow discharge device and upon the completion of the discharge to replace the said means by a source of potential adapted to maintain the discharge in the tube.

A still further object of our invention is to provide a switching arrangement in combination with a varying source of potential and a constant source of potential for producing a mobile glow discharge in a plurality of tube sections progressively and recurrently.

Still another object of our invention is to provide a switching arrangement adaptedto control a high frequency source of power to produce a glow discharge progressively through several sections of a discharge device, and to out 01f the high frequency source in the separate sections and simultaneously connect a low frequency supply thereto to sustain the glow initiated by the high frequency source; the same switching arrangement being adapted also to cut off the low frequency power supply, and to repeat the operations periodically.

These and other objects of our invention are obtained by novel arrangements of circuits in combination with gaseous discharge devices, as will be more fully understood from the following description and by reference to accompanying drawings, in which:

Figure 1 is a schematic diagram of an arrangement for exciting a unit glow discharge device in accordance with our invention; Figs. 2 and 3 show modified arrangements of the system shown in Fig. 1; Fig. 4 shows how a glow discharge device of large proportions may be divided into sections to be excited in the manner shown in Fig. 1, 2 or 3; Fig. 5 is a schematic diagram of a circuit and switching arrangement for exciting the several sections of a glow discharge device successively in the manner shown in Fig. 1; Fig. 6 is a similar schematic diagram showing a modifled switching and circuit arrangement for exciting the several sections ofv a glow discharge device in accordance with our invention; and Fig. '7 shows schematically a selection of variable I prising a coil 5 and a condenser 1, is provided for emphasizing the current supply taken from the high frequency source I9. The oscillating power is transferred by means of a link circuit from the oscillating source I9 through coupling coil 6 to the tank coil 5 and the exciter coil 4. The three coils 4, 5, and 6, are conveniently arranged with coil 5 surrounding exciter coil 4, and coil 6 surrounding both coils 5 and 4. We do not, however, limit ourselves to this coupling arrangement. The link circuit between the oscillating current source I!) and the exciter coil 4 includes the coupling coil 20, blocking condenser 9, coupling coil 6, blocking condenser 8, switch I5, and variometer l4. The blocking condensers 8 and 9 as well as the blocking condenser l0, exhibit practically no reactance to the high frequency current but act as open circuits to the current from the low frequency current source 2|. The low frequency current source 2| is conveniently a commercial power supply having a frequency, say, of or cycles per second. The high frequency current source may be an alternator or an electron tube arrangement, as described in detail in our copending application Serial Number 43,742. The function of the variometer I4 is to vary the high frequency power applied to the exciter coil 4, and make the glow form progressively in the tube l.

A ground 22 is provided and connected to one side of the link circuit and to the low. frequency source 2| to stabilize the potentials relatively throughout the system. As fully set forth in our copending application Patent Number 2,121,829, the discharge will start at terminal 2 or 3 depending upon the relative potentials thereof which can be predetermined by the disposition of the coupling coil 6 with respect to the exciter coil 4. As shown in Figs. 1, 2, 5 and 6, the voltage induced in the left hand portion of coil 4 and impressed on terminal 2 will be relatively greater than the voltage induced in the right hand portion and impressed on the terminal 3. Under a varying exciting voltage, the terminal 2 will therefore reach a potential causing discharge in the tube before terminal 3, and the discharge will therefore progress from terminal 2 to terminal 3 under increasing exciting voltage. In Fig. 3, and also in Fig. 2, the'relative potentials may be determined by the relative positions of the tap connections 25-28 to the coil II which functions as an auto-transformer.

Reference characters II and I2 denote the primary and the high potential secondary respectively of a low frequency transformer. Referenc'e characters I! and I8 denote the coil and variable condenser, respectively, which comprise the tuning circuit of the oscillating current source in Figs. 1 and 5, and reference character l6 denotes a switch for controlling the low frequency power. The operations for producing and sustaining a mobile discharge, in the system of Fig. 1, are as follows. With both switches I5 and I6 open, switch 15 is at first closed manually or automatically; the variometer l4 then is varied to increase the high frequency power applied to the exciter coil 4 until the glow discharge 2, fills the entire length of the tube. The glow will start, say, from terminal 2 and increase toward terminal 3 of discharge device I, as the oscillating power is increased. The variometer l4 may be a variable reactance, a variable resistance or the like, as we have indicated in Fig. 7. When the glow has completely filled the discharge device 1, switch I6 is closed and switch I5 then immediately opened with the result that the glow discharge is sustained by commercial frequency current from the source 2|. of the blocking condensers 8 and 9, the link circuit 20. 9, 23, 6, 8, 24, l5, I4, 20, will not act as a short circuit on the low frequency supply, for the condensers 8 and 9 form a very high reactance with respect to the commercial frequency 15 current of source 2i. Since the glow of the tube I is now sustained by the low frequency source, the high frequency power can now be applied to a second tube not shown in Fig. 1, to make a mobile discharge continue in the second tube, and subsequent tubes, as will be explained in more detail in connection with Figs. 5 and 6. The operations above described may be effected automatically by a common actuating means as indicated by the interconnection of the elements with a motor device 69.

Figure 2 shows a modification of the circuit of Fig. 1. Reference character I denotes again a section of a glow discharge device, with terminals 2 and 3, and 4 indicates the exciter coil, with a blocking condenser at Ill. Reference character l9' indicates the oscillating current source with a tank circuit formed by the coil I1 and variable condenser I8. The source I9 connects with the coil l1 through taps 25 and 26, adjustably disposed on the coil. The coupling coil 20, in Fig. l, is omitted in Fig. 2 and the link circuit connects directly to the coil l1 through taps 21, 28, and it will thus be noted that the coil l'l' acts-as an autotransformer in the high frequency power circuit. In our experiments, we have found this to be of great advantage because, with such an arrangement the motion of the glow under increasing power as controlled by means of variometer I4, can be made smooth, while with some other arrangements, the glow discharge may stick for a while at bends of the discharge tube, and then, suddenly jump towards the end of another portion of the glow discharge device. Condensers 8 and 9 are provided also in the circuit of Fig. 2 as blocking condensers in order to prevent the link circuit 6, 9, 21, 28, I4, l6, 6, 6, from becoming a short circuit on the commercial frequency supply of source 2|. The operation of the circuit of Fig. 2 is the same as explained in connection with Fig. 1.

Fig. 3 illustrates a further modification of the exciting and sustaining circuits for a single tube section. As in Fig. 2, an auto transformer I1 is used. The essential difference in the connection of the auto transformer as indicated in Fig. 2 and that in Fig. 3, is that in Fig. 3 the terminals 21 and 2. connect directly in circuit with the discharge tube section I, and no link circuit is required. In our experiments, we have found that with such an arrangement, there is no stalling in the motion of glow discharge patterns. Reference characters 8 and 9 denote again the blocking Because 10 when both switches l5 and I3 are closed. Variometer l4 and the low frequency source 2| are provided in Fig. 3 as in Figs. 1 and 2; and the operation of Fig. 3 is similar to that of Figs. 1 and 2, as hereinbefore detailed, and as will be further developed in connection with Figs. 5 and 6.

Fig. 4 illustrates the adaptation of several glow discharge sections to produce an enlarged display; in this particular case, three sections are employed to form the word Flolite." The first section reads Flo; the second, "li; and the third, te. The dotted portions 34, 43, 53, and 55 indicate sections of the tubes, the glow from which can not be seen, the sections being adapted to complete the gaseous path. In sign work, such sections are either mounted behind visible glow portions of the advertising sign, or blackened so that the internal glow can not be noticed. According to the system of our invention, under the action of power from the high frequency source l9, shown in the preceding figures, a glow discharge will form at 3|, and as the variometer l4 increases the high frequency power impressed on the exciter coil 4, the glow will progressively increase in the tube f om 3| through the portions 32, 33, 34, and which form the F, Dortions 33, 31, 33, and 39 which form the l, and

portions 40 and which complete the o, and

an automatic switching arrangement will close switch l3, shown in the preceding figures, so as to apply suflicient low frequency power to sustain the glow. Immediately after the low frequency power is applied, the switch l5 will be automatically opened, leaving the section Flo in a state of glow. Thereafter, a further switching arrangement will connect the high frequency source l9 to the second section 1i and a glow will form at 42 which will progressively increase in the tube under the influence of the high frequency power as controlled by variometer l4. As

the high frequency power is increased, the glow will progress from 42 through the portions 43, 44 and 45 forming the l, and portions 43, 41 and 48 to 43 forming the dotted i. As the previous section, Flo, is maintained glowing by means of the low frequency current supply from source 2 I, and in the meantime, as just described, the word 11" was traced, it is apparent that the combination Floli is made to glow by these two consecutive operations. Now, a further switching arrangement will supply the low frequency power also to the second section 1i and automatically interrupt the flow of high frequency current thereto. Thereafter, the automatic switching arrangement will likewise connect the power sources to the third section te so that a glow beginning at 53 and progressing through portions 5|, 52, 53 and 54 will trace the t", and through portions 55, 53, and 51 will trace the e. Thus, the third section te also glows, and the word Flolite is complete. After having applied the low frequency power and disconnected the high frequency supply from the section te, the full glow over the entire word T'lolite can be maintained for a certain period of time, after which, the low frequency power for all sections may be cut off automatically by means of the switching arrangement.

With the foregoing scheme in mind, we refer now to Fig. 5, which illustrates an automatic switching arrangement embodying the simple system of Fig. l in combinations whereby the different sources of power may be connected in sequence, as described with respect to Fig. 4, with the several discharge tube sections la, lb, lo, and

Id. For the sake of simplicity, the variometer I4 is shown in circuit as in Fig. 1, and its operative connection with the switching system indicated by the dotted line 33. It will be understood that the variometer is varied directly in connection with the switch arms 32 and 31 on the shaft 33, by the motor device 33, in such a manner that the impedance thereof is maximum at the beginning of contact of the switch arm 31 with the several coacting segmental contacts 33-33, and a minimum at the breaking of connection with the respective contacts.

For cleamess sake, the four sections In, lb, lo and Id, are shown apart rather than in the manner of Fig. 4 as closely disposed elements in a composite discharge display. The tube sections terminals 20 and 3a, 2b and 3b, 2c and 3c, and 2d and M, respectively. Similar exciter coils 4a, 4b,

4c, and 4d, are provided across the sectional discharge tubes la, lb, lc, and Id, respectively. The fundamental circuit for the arrangement indicated in Fig. 5, is the network shown in Fig. 1, in which a magnetic coupling to the source exists in the transformer I1, 23. The power transfer takes place from the tank circuit l1, ll, of the high frequency source l3 through the secondary or coupling coil 23 and the link circuit to the coupling coils 3a, 3b, 3c, 3d of the respective sections la, lb, lo, and Id. The low frequency source is again represented at 2|; and the ground 22. Storage tank circuits for emphasizing the high frequency power in the respective exciter coils are shown at 5a and 3a, 5b and 3b, 5c and 3c, and

5d and 3d. Reference characters Ila and l2a, llb and l2b, Ho and He, and lid and IM, denote step-up low frequency transformers with l2 indicating the high potential winding in each instance.

Blocking condensers 3a, 3b, 3c and 3d, are provided respectively, as indicated from Fig. 1, and common leads from the coils 3 and ll are employed. One terminal of each coil 3 and each coil l l is grounded through a common lead which also connects to one terminal of the low frequency source'2l and one terminal of the coupling coil 20 in the. high frequency supply system from source l3. Seperate leads are brought in common from the other terminals of coils 3a and ll (1., 6b and llb, 3c and Ho, and 3d and lld, to the high frequency current and the low frequency current switching systems.

In order to differentiate the switching arrange-'- ment for the high frequency supply l9 from the switching arrangement for the low frequency supply 2 l, the switch plate and the corresponding contacts for the high frequency supply are shown with vertical shade lines, while the switch plate and the corresponding contacts for the low frequency supply are shown with horizontal shade lines. Reference character 31 represents the switch plate for the high-frequency supply and reference characters 33, 34, 35, and 33, the corresponding contact sectors for connecting the high frequency supply to coils 3a, 3b, 3c, and 3d respectively. The switch plate 32 for the low freq cy supply is insulated from the switch plate 31, and connected to the source 2!. The switch plate 31 is connected to variometer l4. The contact sectors for the low frequency supply to coils lla, lib, He, and lid are 53, 53, 33, and 3|, respectively. Both switch plates 32 and 31 as well as the variometer indicated at l4, rotate together and in the arrangement of Fig. 5, in a clock-wise direction as indicated. For the position shown,

variometer I4 is adjusted to provide maximum. impedance to a high frequency current flow as switch plate 61 makes contact at the left end of sector 63. Hence, as the'switching arrangement is driven clock-wise, by means of a motor device 88 or the like, little high frequency power is at first supplied but with increasing angular displacement of switch plate 61 with respect to the position indicated in Fig. 5, the impedance of variometer l4 decreases, and the power supplied to the exciting coil 4a. increases, causing a glow discharge to progress from terminal 2a. towards terminal 3a. The structure is so designed that when the switch plate 61 has completely described sector 63, the section la is covered with a glow from 20. to 3a. Immediately before the switch plate 61 loses contact at the right end of sector 63, switch plate 62, which also turns clock-wise, makes contact with the left end of sector 58, thus supplying low frequency power by means of transformer lla, l2a, to section la. This low frequency power sustains the glow which was initiated by the high frequency supply. Hence; after switch plate 61 leaves sector 63, the glow in section la. is sustained by power from the source 2l, and will be sustained as long as the switch plate 62 makes contact with the long arc sector 58.

As the switch plates 61 and 62 continue clockwise rotation, switch plate 61 will contact with the left end of sector 64. At this position, the variometer l4 again has a maximum impedance, but as contact 61 sweeps to the right along sector 64, and variometer I4 is correspondingly varied, the impedance decreases, thus causing a glow in section lb increasing from terminal 2b towards terminal 3b. Shortly before contact plate 61 comes to the end of sector 64, the entire section lb is covered with glow, and switch plate 62 makes contact with sector 59, while maintaining contact with sector 58, thus supplying low frequency power not only to section la, but also to section lb. Hence, when switch plate 61 leaves sector 64 a full glow discharge will be sustained by means of low frequency power supplied from source 2| in both sections, la and lb.

Now as switch plate 61 begins to make contact with sector 65, the impedance of variometer I4 is again at its maximum value, but with continued rotation decreases in.value and switch plate 61 moves along sector 85. Thus, a glow discharge forms in section lc at terminal 20 and grows towards the terminal 30. When the switch plate 82 makes contact not only along 58 and 59, but also at the beginning of sector 60, low frequency power is supplied to all three sections la, lb, and lo. Switch plate 61 then breaks contact with sector 65 and makes contact with sector 66, initiating a glow at terminal 2d of section Id by means of high frequency power from source IS. The glow is caused to progress towards 3d in the same manner as above described, and when switch plate ,62 also contacts sector 6|, low frequency power is also supplied to section ld. Hence, for sections la, lb, lo and Id, the glow is thus sus tained by means of the low frequency power supplied by source l3. When switch plate 62 leaves sectors 58, 59, 68 and 6i, the glow disappears, and there will be an interval during which no 'discharge is produced. When the switch plates 62 ,and 61 and the variometer H are again in the relation indicated as the beginning, with respect to- Fig. 5, the display is repeated in the manner above described.

Figure 6 illustrates another form of an automatic switching arrangement of our invention. For the sake of clearness, sections lb, la, and Id, are shown only in part while the characteristic first section la is shown in detail. The arrangement shown in Fig. 6 differs from that illustrated in Fig. 5, since automatic timing is provided by means of a relay device 15 connected with the insulated lever 8| for actuating switch blades 84 and 85, and operative under the control of contacts 13 and 14 associated with the variometer l4. As in the previous figures, the variometer has initially a large impedance acting in the link circuit, 20, 6, and this impedance is progressively reduced in order to elongate the glow discharge produced by means of high frequency power delivered by source IS. The 'variometer can, of course, be used in various portions of the high frequency circuit in order to increase the high frequency power delivered to the glow sections.

Variometer l4 comprises a resistance winding Ma and a contact arm 12 for varying the effective resistance in the circuit. A second contact arm 13 is provided in conjunction with arm l2, but insulated therefrom, for coaction with a fixed contact 14. Contact arm "is connected with the low frequency source 2l, and contact 14 with the actuating coil .16 of the trip relay device generally indicated at 15. The other end of the coil 15 is connected with the low frequency source 2i, and thus it will be seen that the contacts l3, 14, control the action of the relay device 15. Switch arms 12 and 13 are driven with constant angular velocity in a clockwise direction as shown, bya motor device 69'. The winding I40. is shown in Fig. 6 as substantially circular in form with a portion of the circumference open as at Mb. Switch arm 12 contacts the winding Ida and the effective impedance of the device is decreased from a maximum in the position shown, to a minimum when arm 12 contacts the winding Ha adjacent the connection therefrom. Moving from the minimum impedance position, the switch arm 12 momentarily produces an open circuit as it passes the open portion l4b, before again contacting the winding Ila in the position of maximum impedance. The switch arm I3 is adapted to connect with the fixed contact 14 immediately prior to this open circuit condition, .so that the relay I is actuated and the low frequency power supply connected to replace the high frequency power supply, as hereinbefore explained. The switch arms are shown in the simplest relation to accomplish this operation, that is, switch arm 13 is slightly displaced behind switch arm 12 and the contact 14 disposed adjacent the connected end of the winding Ma.

It will be noted that the lead from contact 14 carries both high frequency current to coil 6a andlow frequency current to coil 16, and blocking condenser H is therefore provided to prevent short circuits when the contact 14 and switch arm 13 connect. Blocking condenser I8 is provided in the other high frequency lead for similar reasons. It will also be noted that contact sectors a, b, c, and (1, connect respectively to the low frequency step-up transformers feeding the tube sections la, lb, la, and id; andthat contacts ,a', b, c, and (1', connect respectively to the high frequency coupling coils 6a, 6b, 6c, and 6d, feeding the several tube sections.

The operation of the system is as follows. At the start, switch blade 85 is moved onto contact a, and maximum impedance in the variometer link circuit gradually decreases and a corresponding increase in the high frequency power transmitted towards the exciter coil 4a of section la causes theglow discharge to form progressively in tubing la from terminal 2a. towards terminal la. When contact'arm l2 approaches the connected end of winding Ila, the trailing contact arm 13 connects with contact II, which energizes winding 16 of the alternating current trip relay 15 which actuates armature I1 and the associated pawl 18 and ratchet wheel I9 to rotate the shaft 8i one step- The switch blade 84 on the shaft 8| connects with contact a, and the switch blade 85 is moved from contact a to contact b, not leaving contact 0., however, until switch blade 84 contacts. with a. Hence, the switch blade 84 by making contact with sector a causes tube section la to be energized by means of the low frequency power, while the switching from contact a. to contact b by means of switch blade 85 interrupts the high frequency excitation of the firsttube section la, and starts the high frequency excitation of the second section lb.

Both contact arms 12 and 13 pass again to the starting position as indicated in Fig. 6, and maxi! mum impedance is again effected in the link circuit, which now connectes to the second section lb.

Hence, continued clock-wise rotation of the two contact arms I2 and I3 will cause the glow discharge to form progressively in tubing lb, and near the end of 360 rotation, contact arm It will again, through contact 14, cause the alternating current relay I5 to be energized, which by means of the insulated lever 8 l causes the switch blade 84 to make contact with sector b while maintaining contact with it. Hence, sections I a and lb will be energized simultaneously with low frequency power. At the same time that the trip relay causes the sector 84 to connect also to contact b, the contact arm 85 is moved from b to c', and the highdrequenct supply is disconnected from section lb and connected to the next section lc. In a similar way, the action is repeated for the third section and the fourth section Id, after which all four sections, la, lb, lo, and Id, may be energized for a certain time interval by means of the low frequency supply delivered by source 2|, until another trip of the alternatingcurrent relay disconnects the low frequency supply energizing all four sections la, lb, lo and id. The display is begun again with the switch arms in the positions shown in Fig. 6 for starting a glow at terminal 2a of the first section la. y

Fig. 7 shows schematically different types of variable devices which may be employed to regulate the high frequency current to the discharge tubes. A variable resistance device is represented at l4, which may be conveniently adapted to a switching arrangement as has been shown in Fig. 6. Reference character It" indicates a variable reactance device which has advantages .over the resistance type of control as are well known in the art. A modified reactance device is shown at H' and comprises a pair of series connected reactances variably coupled so as to eifect a variable reactance in the circuit. In lieu of any of the foregoing devices, any suitable variable impedance device may be employed.

With respect to Figs. 1, 2, 3, 5 and 6, it will be noted that the switching in the high frequency line is done by means of a single pole arrangement. In some cases, because of capacitance effects, glow discharge tubes disconnected on one side only from the high frequency source may show small glows at the connected terminal ends of the tubes. This can be avoided by providing a double pole switching arrangement. In order not to cause confusion, however, only the single pole arrangement has been shown. It is obvious that the low frequency supply action for the last section can be omitted without cha ng the operation since the power of the high frequency source is sufiicientfor sustaining the glow of the final section. This is another simplification which is within the scope of our invention.

The circular switching arrangements can be i replaced by a set of contacts mounted on a cylincircuits indicated in Fig. 2 and Fig. 3. We can also make use of the detailed networks described in full in our copending application Serial Number 43,742 in the systems of our present invention.

Thus, while we have described our invention in certain preferred embodiments, we desire it understood that modifications may be made, and that no limitations upon our invention are intended, except as are imposed by the scope of the appended claims.

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

1. In a glow discharge system, a glow discharge display comprising a plurality of glow discharge sections, means for forming a glow discharge in a first one of said sections progressively from one terminal to the other terminal thereof,

section, and subsequently disconnecting the first said-means from the said second section; the last said means being similarly operable with respect to each of said sections, and being finally operative to disconnect the second said means from all said sections.

2. In a, glow discharge system, a glow discharge display comprising a plurality of glow discharge sections; means for forming a glow discharge in any one of said sections progressively from one terminal to the other terminal thereof;

means for maintaining glow discharges in said sections; and automatic means for connecting the first said means to a first one of said sections, subsequently connecting the second said means to the said first section, and subsequently disconnecting the said first means therefrom;

said automatic means being operable further for' connecting the first said means to a second one of said sections, subsequently conlnecting the second said means to the said second section in' addition to the connection thereof to the said first section, and subsequently disconnecting the first said means from the said second section; said automatic means being similarly operable with respect to each of said sections, and being finally operative to disconnect the second said means from all said sections.

3. In a multiple unit glow discharge system: a plurality of glow discharge tubing units; a high frequency current oscillator including control means adapted, when connected to a glow discharge unit, to cause progressive illumination therein; means for connecting said oscillator in sequence to said units; a low frequency current supply means for sustaining a glow discharge in said units; and meansfor connecting said low frequency current supply meansto the units as said oscillator completes progressive illumination therein.

4. A dual control system for producing progressive illumination throughout a plurality of glow discharge tubing units comprising: a high frequency current oscillator including control means capable of producing a progressive glow discharge from one end to the other of a glow discharge ing unit whereby the glow discharge progresses through succeeding tubing units while the glow discharge in preceding tubing units is maintained.

5. In a multiple unit glow discharge system: a plurality of glow discharge tubing units; an alternating-current-operated animator adapted, when connected to a tubing unit, to cause progressive illumination therein; means for connecting said animator in sequence to said tubing units; means for sustaining a glow discharge in said units; and means for connecting said sustaining means to said units as said animator completes progressive illumination therein whereby illumination progresses throughout a plurality of tubing units to produce a writing effect therein.

RICHARD H. SEAMAN. CARL A. SCHWENDEN.

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