US2591729A - Electronic discharge tube system for animated or flowing electric signs and display devices - Google Patents

Description

April 8, 1952 R. H. SEAMAN ELECTRONIC DISCHARGE TUBE SYSTEM F OR ANIMATED OR FLOWING ELECTRIC SIGNS AND DISPLAY DEVICES 2 SHEETS-SHEET 1 Filed Jan. 6, 1948 INVENTOR.

ATTOR/l/Ey April 8, SEAMAN ELECTRONIC DISCHARGE TUBE SYSTEM FOR ANIMATED OR FLOWING ELECTRIC SIGNS AND DISPLAY DEVICES Filed Jan. 6, 1948 2 SHEETSSHEET 2 HHHHHOHHOHHO 'i' Z /g 1121. E I I 7 INVENTOR.

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Patented Apr. 8, 1952 ELECTRONIC DISCHARGE TUBE SYSTEM FOR ANIMATED OR FLOWING ELECTRIC SIGNS AND DISPLAY DEVICES Richard H. Seaman, Los Angeles, Calif., assignor to Mega Corporation, Los Angeles, Calif., a corporation of California Application January 6, 1948, Serial No. 682

9 Claims.

My invention relates broadly to animated electric signs and more particularly to an improved circuit arrangement and structure for an elec tronic discharge tube system particularly adapted for exhibiting animated luminous effects.

This application is a continuation-in-part of my application Serial No. 622,056, filed October 13, 1945, now abandoned, for Flowing Neon Sign and Switch Therefor.

One of the objects of my invention is to provide a circuit arrangement for a hot cathode type of electronic discharge tube arranged for estab lishing flowing effects in luminous discharge which is readily restricted and controlled.

Another object of my invention is'to provide a circuit arrangement for a hot cathode discharge tube and thermally controlled switch means therefor for predetermining the path of electronic discharge for producing a predetermined pattern of luminous effect.

Still another object of my invention is to provide an improved structure of electronic discharge terminus for multiple anode electronic discharge devices operative to produce controlled luminous discharge effects.

Other and further objects of my invention reside in the improved hot cathode type of the electronic discharge system for luminous discharge tubes as set forth more fully in the specification hereinafter following by referring to the accompanying drawings, in which:

Figure 1 diagrammatically illustrates the arrangement of hot cathode type of gaseous luminous discharge tube of my invention and the manner of thermally controlling the flow of the luminous discharge through the tube system; Fig. 2 is a fragmentary schematic view of one of the several anodes used in the tube system of Fig. 1 and showing the arrangement of thermal switch employed to control the path of current to the anode, the switch being shown in closed position for exciting the anode; Fig. 3 is a view similar to the view shown in Fig. 2, but showing the thermal switch in open position; Fig. 4 is a longitudinal sectional view taken through the hot cathode structure of the electronic discharge tube and the excitation circuit associated therewith and illustrating the thermally operated switches associated with the multiple anodes of the discharge tube; Fig. 5 is a horizontal sectional view taken substantially on line 5-5 of Fig. 4; Fig. 6 is a fragmentary perspective view of the cathode structure; Fig. 7 is a fragmentary vertical sectional view through a modified form of hot cathode structure which may be employed in the tube.

system of my invention; and, Fig. 8 is a transverse sectional view taken on line 88 of Fig. '7.

My invention is directed to an improved construction of hot cathode luminous discharge tube which operates without the employment of rotating switches, commutators and circuit interrupters, but utilizes an arrangement of thermally controlled switches which progressively control the growth and limitation of the luminous discharge path within the tube. I eliminate the need for moving parts in the electronically controlled tube system of my invention by arranging a progressive series of anodes in predetermined relation to a hot cathode electronic discharge device. The anodes are spaced in relation to the hot cathode and are individually thermally controlled so that the path of luminous discharge progressively varies in the discharge tube as the anodes become progressively activated. Thus a fiow discharge may be controlled for writing words in luminous discharge or producing animated efiects applicable in advertising designs and luminous displays. The circuit arrangement of my invention employs a full-wave rectifier for excitation of the successively spaced anodes of the multiple anode electronic discharge tube system of my invention. The system lends itself to the utilization of a multiplicity of coacting tube sections, the voltage supply to each of which is maintained at relatively low value thereby adapting the design of my invention to the requirements of Boards of Fire Underwriters by restricting the voltage required for operation of each tube section.

Fig. 1 illustrates at l a glow tube I containing at one end a hot cathode 3 covered by protective device 2, with spacially distributed successive anodes 4, 4a, 4b, 4c, 4d, 4e, 4f, 4g and 5 disposed along the tube. A growing glow discharge from the cathode 3 towards final anode 5 is controlled by thermal interrupters M, Ma, [4b, I40, Md, Me, [4 and i5. The emission from hot cathode 3 is directed through or around protective device 2. This device is shown more particularly in Figs. 4-8 and comprises a cylindrical sleeve member 2a mounted on supports 2b extending from the end Ia of tube I. The sleeve 2a has a disk 2c mounted in spaced relation thereto through supporting members 2d. The disk 2e has an opening at the front as shown at 2 in Figs. 7-8, or is solid as shown in Figs. 4-6 and spaced from cylindrical sleeve member 2a so that ionization may leave or enter through the separation space provided by the supporting members 24. When the solid disk 20 is used as shown in Figs. 4-6 the periphery 3 of the disk is spaced from the inner walls of the tube I as shown in Figs. 4 and 5. When the apertured disk 2c is used the supporting members 2d are omitted and disk 2e rests directly upon the peripheral edge of the cylindrical sleeve member 2a.

By virtue of thermal interrupters, such as I4, a positive anode potential acts progressively on anodes l a, 4b, dc, dd, ie, if, 45g and 5. The thermal interrupter and its action is described in detail in my application Serial Number 622,056, filed October 13, 1945, supra. Figs. 2 and 3 herein show the two positions of the thermal interrupters.

Three elements I6, I! and I8 are maintained in a vacuum within the tube I4 as is shown for example in Fig. 4. In Fig. 2 metal strip I1 is resilient and has the form of a substantially inverted L with a contact portion I'Ia depending from the end thereof and normally making contact with the end I8a of resilient metal strip I8. The element I6 is a suitable Wire, which for normal temperature ranges applies tension to strip I'I toward the left viewed in Fig. 2 and keeps contact I'Ia on contact IBa as shown in Fig. 2. However, when sufiicient current enters lead II], the wire It becomes longer, causing a sag and contact Hit of strip I'I moves to the right by reason of the inherent flexing in strip I1 and opens contact IBa as shown in Fig. 3 so that current passing into lead It can emerge on lead I I, but no longer also on lead I 2.

Each of the thermal interrupters I I are relatively small in size and comprise an evacuated envelope I9 with abase IGa and pins projecting therefrom which are connectable through socket members with the leads II), II and I2 for establishing connection with the elements I6, I! and I8 within the thermal interrupter tube. The fact that contact portions Hu and I8a are maintained in a vacuum reduce or substantially eliminate arcing at the contacts. The inherent flexing of the metallic strips I1 is sufficient to maintain a closed electrical'cirouit between contacts IIa and Ida under normal conditions tensioned by wire element It as represented in Fig. 2. However, as shown in Fig. 3 the inherent resiliency of strip II causes the strip II to flex into a position opening contacts I'Ia and IBa when wire element I6 becomes heated and is elongated. Thus the spaced anodes distributed to tube I of Fig. 1 becomes successively effective to permit the growth of the discharge from one anode to another. These thermal interrupters eliminate the necessity for rotating arm devices as the interrupters successivelyoperate in a series circuit for controlling the progressive growth of the luminous discharge within the glow tube I.

The circuit is energized from a source of alternating current applied-at terminals 20 of the primary winding 2| of power transformer 22. The power transformer 22 in Figs. 1 and 4 includes a-plurality of secondary windings 23, 24

and 25, where secondary winding 23 serves to supply heating current to the cathode 3 of the glow discharge tube I, while secondary winding 25 serves to supply heating current to the cathodes-jof} the-full- wave rectifier tubes 26 and 21. The plate. potentialfor, the full- wave rectifier tubes 26 and 21 is supplied through secondary winding 24. E v

When customary commercial alternating voltage -is applied to the primary terminals 20 of transformer 22, the filament 3 will become incandescent due to the voltage of the secondary 23.

In the same way the filaments of the respective half-wave rectifiers 2t and 2'! will become incandescent by virtue of the voltage of the secondary 25. The lead It is then at a positive voltage while the device 2 is at a negative voltage due to the action of the full-wave rectifier. After the filaments of the rectifier tubes and the glow tube are functioning, the positive voltage of the fullwave rectifier is applied, at first, to all anodes 4, 4a, 4b, 4c, 4d, 4e, 4f, 19 and 5. The discharge path from device 2 to anode I ofiers the least internal glow tube resistance to be overcome, and a glow discharge will at first strike from device 2 towards the first anode 4 and no glow will exist along the remainder of tube I. The space from anode 4 to anode 5 remains, therefore, without any glow discharge. However, when a glow discharge sets in between device 2 and anode 4 a current is established between the positive-inlead connection II! of tube It and. the anode 4. This current will heat up the heat-sensitive wire I6, depending on the physical dimensions of this wire and its material, and the wire IE will gradually elongate and loosen up the tension of I6 on element II in Fig. 3, and open the contact at I'Ia and I8a which connects elements I1 and I8 electrically. When this happens the current path to anode 4 is likewise interrupted and no positive potential is applied to anode 4. But. by virtue of connector II, shown in Figs. 1 and 3, and unheated thermal interrupter I8, a positive potential still is applied to anode Ila, as well as to all successive anodes such as Alb, 4c, 4d, 4e, 4f, 49 and 5. The glow discharge jumps, then, to anode 4a, since this is the path of least resistance. Now, after a time interval, the heat-sensitive wire I 6 of tube I la becomes warmer and warmer, elongates and opens the contact of tube Ida. Therefore, anode ea becomes disconnected from the positive potential supply, and the glow discharge jumps to anode ib which is still at a positive potential as are all the other following anodes such as 40, 4d, 46, 4f, 4g, and 5. In exactly the same manner the glow discharge from device 2 grows towards the final anode 5 and is sustained for a while until the contact of the thermal interrupter tube I5 opens due to the gradual and accumulative heating of wire element I6. When thermal tube I5 opens, the glow discharge is quenched, and after a while the entire process repeats again in successive cycles over and over.

The system has the inherent feature and ad vantage that no revolving mechanism is required which may get out of order. The system also has the advantage that with hot cathodes a much steadier glow-discharge with increased brilliancy is secured.

When the display tube or writing sign constructed by use of the tube of my invention is initially started all of the thermal interrupters are normally closed. The condition illustrated in Fig. 1 is that discharge has progressed from-device 2 to anode ca, having already caused such heating of wire element It in tube I4 that the wire element I6 in tube M has expanded, thus opening the circuit between contacts Ma and I8a in tube I4 (Figs. 1 and 3), and allowing the current to pass through lead II to connection ID of tube I4a through wire element It in tube I la, strip II in tube I la, contact I'ia in tube I la and to contact I8a to strip I8 and lead I2 to anode 4a which receives the discharge from device 2 causing a glow between device 2 and anode 4a. In a predetermined time interval the circuit through thermal interrupter tube 14a. will open, thereby successively placing tube [4a. in the circuit for activation of anode 4b. This same process repeats throughout the chain of thermal interrupters.

The structural arrangement of the hot cathode device 2 with respect to the envelope of the glow tube is very important. It will be observed that the cathode structure enters perpendicularly to the tube section I which contains the various anodes. Such a provision prevents the light of the filament 3 from showing up in the actual gloW space. The electronic discharge escapes not through the end disk 2c but between legs or supporting members 2d which support the end disk (Figs. 1, 4 and 6). I have indicated the discharge path by arrows in Fig. 4. In the alternate way of protecting the filament 3 shown in Figs. 7 and 8 hole 2f is provided at the center of the end disk 2e. In this case there are no legs supporting the end disk 2e but a closed cylinder supports the disk as shown by cylindrical member 2a. Other modified forms of the device 2 may be employed but in all instances the hot cathode device is maintained out of the line of vision of the display or writing sign constituted by the structure of my invention.

In order to satisfy the Board of Fire Underwriters, several tube sections, similar to tube 1 of Fig. 1, may be used which are operated from separate full-wave rectifier supplies and the potential of each tube section thereby maintained at a minimum.

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

1. An animated electric sign including an electronic discharge tube forming part or" said electric sign, a cathode of the filamentary type disposed in one end of said tube, a multiplicity of spaced anodes distributed along said electron tube, an alternating current power source for energizing said filamentary cathode, rectifying means connected with said alternating current power source, means for supplying direct current impulses to said anodes, and a multiplicity of thermal interrupters for progressively activating each of said anodes with direct current pulses from said rectifying means for predetermining the effective length of the discharge path from said filamentary cathode to the said respective anodes.

2. An animated electric sign including an electronic discharge tube forming part of said electric sign, a cathode of the filamentary type disposed in one end of said tube, a multiplicity of spaced anodes distributed along said electron tube, an alternating current power source for energizing said filamentary cathode, rectifying means connected with said alternating current power source, means for supplying direct current impulses to said spaced anodes, and a plurality of thermal switches having expandable elements electrically connected in a series circuit and each including a coacting contact element individually connected to a selected anode, and an electrical connection between said means and said series circuit through said switches whereby rectified current is progressively applied to said anodes in accordance with the progressive operation of said thermal switches.

3. A luminous discharge tube system comprising in combination an evacuated envelope, a cathode of the filamentary type disposed in one end of said envelope, a multiplicity of spacially disposed anodes distributed along said envelope in the electron discharge path of said filamentary cathode, a thermal switch individual to each of said anodes, each of said thermal switches including an expandable element and a pair of contact members associated therewith, a connection extending from one of said contact members to the associated anode, a series circuit including the expandable element of each of said thermal switches, a power source of alternating current, means for energizing said filamentary cathode from said power source of alternatin current, a rectifier system connected with said power source of alternating current, and a connection between the positive side of said rectifier system and the series circuit including each of said thermal switches whereby the contact members of said thermal switches may be successively and progressively controlled for selectively applying polarizing potential pulses to each of said spaced anodes in succession for effecting a growth of the electronic discharge of progressively increasing length from said filamentary cathode in said electron tube to said spaced anodes in succession.

4. A luminous discharge tube system comprising an evacuated envelope including a longitudinally extending section and an interconnected section extending substantially perpendicular thereto, a plurality of spacially disposed-anodes positioned in said longitudinally extending sec tion, a cathode of the filamentary type located in said perpendicularly disposed section, a thermal switch individual to each of said anodes, a series circuit common to all of said thermal switches, a power source of alternating current, means for energizing said filamentary cathode from said power source of alternating current, a rectifier system connected with said power source of alternating current, and a circuit connecting said rectifier system with said series circuit for sequentially applying polarizing potential pulses through the individual thermal switches to said spaced anodes in succession.

5. A luminous discharge tube system comprising an evacuated envelope including a longitudinally extending section and an interconnected section extending substantially perpendicular thereto, a plurality of spacially disposed anodes located in said longitudinally extending section, a cathode of the filamentary type positioned in said perpendicularly disposed section, a thermal switch individual to each of said anodes, a series circuit common to all of said thermal switches, a power source of alternating current, means for energizing said filamentary cathode from said power source of alternating current, a rectifier system connected with said power source of alternating current, a circuit connecting said rec tifier system with said series circuit for sequenti'ally applying polarizing potential pulses to said spaced anodes through said individual thermal switches to said spaced anodes in succession, and a protective device associated with said filamentary cathode for substantially blocking visiblelight rays from said filamentary cathode from reaching the elongated section of said tube while permitting unobstructed electronic discharge with respect thereto.

6. A luminous discharge tube system comprising an evacuated envelope including a longitudinally extending section and an interconnected section extending substantially perpendicular thereto, a plurality of spacially disposed anodes located in said longitudinally extending section, a filamentary cathode disposed in said perpendicularly disposed section, a thermal switch individual to each of said spacially disposed anodes.

a series circuit common to all of said, thermal switches, a power source of alternating current, means for energizing said filamentary cathode from said power source of alternating current, a rectifier system connected with said power source of alternating current, a circuit connecting said rectifier system with said series circuit for sequentially applying polarizing potential pulses through said individual thermal switches to said spaced anodes in succession, and a protective device substantially surrounding said filamentary cathode within the perpendicularly extending section of said envelope with an orifice therein allowing unimpeded passage of electrons from said filamentary cathode to said spacially disposed anodes while restricting the visual emission of light rays from reaching the longitudinally extending section of said envelope.

7. A luminous discharge tube system comprising an evacuated envelope including a longitudinally extending section and an interconnected section extending substantially perpendicular thereto, a plurality of spacially disposed anodes located in said longitudinally extending section, a cathode of the filamentary heated type disposed in said perpendicularly disposed section, a thermal switch individual to each of said anodes, a series circuit common to all of said thermal switches, a power source of alternating current, means for energizing said filamentary cathode from said power source of alternating current, a rectifier system connected with said power source of alternating current, a circuit connecting said rectifier system with said series circuit for sequentially applying polarizing potential pulses to said spaced anodes through said thermal switches to said spaced anodes in succession, and a protective device surrounding said filamentary cathode and disposed within the perpendicularly extending section of said envelope, said protec tive device including a cylindrical sleeve surrounding said filamentary cathode and a disk member spaced therefrom and offset from the wall of the longitudinally extending section of said envelope, said disk member being spaced from said sleeve member for allowing the unimpeded discharge of electrons from said filamentary cathode to said anodes While substantially obstructing visual emission of light rays from said filamentary cathode from reaching the longitudinally extending section of said envelope.

8. A luminous discharge tube system comprising an evacuated envelope including a longitudinally extending section and an interconnected section extending substantially perpendicular thereto, a plurality of spacially disposed anodes positioned in said longitudinally extending section, a cathode of the filamentary heated type located in said perpendicularly disposed section, a thermal switch individual to each of said anodes, a series circuit common to all of said thermal switches, a power source of alternating current, means for energizing said filamentary cathode from said power source of alternating current, a rectifier system connected with said power source of alternating current, acircuit connecting said rectifier system with said series circuit for sequentially applying polarizing potential pulses to said spaced anodes through said thermal switches to said spaced anodes in succession, and a hood substantially enclosing said filamentary cathode and oliset from the side of the longitudinally extending section of said envelope within the perpendicularly extending section, said hood including means for emitting electronic discharge to said spacially disposed anodes while substantially blocking visual emission from said cathode from reaching the longitudinally extending section of said envelope.

9. A luminous discharge tube system comprising an evacuated envelope including a longitudinally extending section and an interconnected section extending substantially perpendicular thereto, a plurality of spacially disposed anodes located in said longitudinally extending section, a cathode of the filamentary heated type positioned in said perpendicularly disposed section, a thermal switch individual to each of said anodes, a series circuit common to all of said thermal switches, a power source of alternating current, means for energizing said filamentary cathode from said power source of alternating current, a rectifier system connected with said power source of alternating current, a circuit connecting said rectifier system with said series,

circuit for sequentially applying polarizing potential pulses to said spaced anodes through said thermal switches to said spaced anodes in succession, and a plate member extending transversely to the axis of the perpendicularly extending section of said envelope and offset from the wall of the longitudinally extending section of said envelope, a sleeve member attached to the said plate member and substantially surrounding said filamentary cathode, said plate member being apertured for directing the discharge of electrons to each or said spaced anodes 0 while substantially blocking visual emission of REFERENCES CITED The following references are of record in-th file of this patent:

- UNITED STATES PATENTS Number Name Date 2,020,731 Lederer Nov. 12, 1935 2,056,619 Reger Oct. 6, 1936 2,097,261 Spanner Oct. 26, 1937 2,354,696 Mettler Aug. 1, 1944 2,375,830 Spencer May 15, 1945 FOREIGN PATENTS Number Country Date- 524,748 Great Britain Aug. 14, 1940

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