US2794906A

US2794906A - Gaseous-discharge apparatus

Info

Publication number: US2794906A
Application number: US437106A
Authority: US
Inventors: Harold E Edgerton
Original assignee: Individual
Current assignee: Individual
Priority date: 1954-06-16
Filing date: 1954-06-16
Publication date: 1957-06-04
Anticipated expiration: 1974-06-04

Description

June 4, 1957 H. E. EDGERTON 2,794,906

' GASEOUS -DISCHARGE APPARATUS Filed June 16, 1954 INVENTOR. flzwzo' fmmrolv BYZ M A T T ORNEYS United States Patent-O F GASEOUS-DISCHARGE APPARATUS Harold E. Edgerton, Belmont, Mass.

Application June 16, 1954, Serial No. 437,106

19 Claims. (Cl. Mil-41.4)

The present invention relates to electric-discharge apparatus and more particularly .to gas-filled tubes in which an electric discharge takes place between an anode and a cathode associated with the tube.

An important application of gaseous-discharge tube-s is that of producing flash illumination for such purposes as flash photography or stroboscopy. Flashtubes of this character generally embody an anode and a cathode disposed within the gas in the tube. When an electric discharge is produced through the gas in the tube between the anode and the cathode, a flash of light is emitted through the walls of the tube in the region between the anode and the cathode. This discharge may be initiated by control of the voltage at the anode and the cathode alone, or, preferably, with the aid of an auxiliary or trigger electrode disposed between the anode and .the cathode. Such flashtubes have heretofore been mounted within paraboloidal and similar light-wave reflectors to direct as a beam the illumination produced by the flashes of light from the flashtube. Apparatus of this character is described, for example, in my prior United States Letters Patent No. 2,358,796, issued September 26, 1944, and No. Re. 22,611, issued March 6, 194 5. The fiashtubes therein disclosed are of helical construction disposed in the reflector with the axis of the helix oriented substantially parallel to or coincident with the axis of the reflector. Helical tubes, however, are not only costly to manufacture, but considerable flash illumination is wasted in 'view of the fact that some turns of the helical tube are in front of others. In addition, the light emanating from the tube is not produced only in the region of the focus of the reflector, so that the effectiveness of the reflector -as a beam director is impaired. It has, however, heretofore been proposed to utilize discharge tubes comprising an envelope in the form of a single loop that may be disposed in the focal region of a reflector. Such devices have been suggested, for example, for use in automobile headlights and other types of projector lamps. Such devices,however, are intricate to manufacture and are not particularly suited as highintensity flashtubes ,or for use in flash photography and in stroboscopic applications.

An object of the invention, therefore, is to provide a new and improved gaseous-discharge device that shall not be subject to any of the above-mentioned dis-advantages and that is particularly adapted for use as a flashtube with light-wave reflectors of the paraboloidal type. In summary, the present inventionembodies a flashtube that comprises a tubular envelope looped ,into a single closed ring with the terminal portions crossing at a predetermined point along the ring and diverging from the said point away from the ring. A pair of principal electrodes is mounted within the envelope at the said diverging terminal portions and a trigger electrode is positioned at .a point of the ring displaced from the said predetermined point. An electrical connector is connected toeach off the electrodes and is mounted to extend in a direction substantially perpendicular to the plane of the 2,794,906 Patented June 4, 1957 2v ring toward the reflector. The electrical connectors are received within insulated apertures in the reflector to permit of easy attachment and detachment of the flash- ,tube, and to maintain the flashtube rigidly positioned, when attached, and easily connectable to the flashtube circuit.

A further object is to provide such a flashtube in which the electrode-connection structures themselves serve to provide rigid mechanical supporting means for positioning the flashtube in the exact desired location with respect to the reflector.

Still a further object is to provide a new and improved type of mounting for a gaseous-discharge device.

An additional object is to provide a more efficient and less costly gaseous-discharge device.

Other and further objects will be set forth hereinafter and will be more particularly pointed out in the appended claims.

The invention will now be described in connection with the accompanying drawings:

Fig. 1 of which is a combined fragmentary perspective and circuit diagram illustrating a flashtube constructed in accordance with a preferred embodiment of the pres- .ent invention and connected with a light flash-producing system;

Figs. 2 and 3 are, respectively, front and side elevations of the flashtube of Fig. 1;

Fig. 4 is a side elevation of a modified flashtube construction; and

'Fig. 5 is a fragmentary perspective of a further modification.

Referring to Fig. l, the flashtube 1 is shown in the form of a tube of glass, fused quartz or other light transparent material, looped into a single ,closed ring, preferably of circular contour. The rightand left-hand terminal portions 3 and 5 of the ring cross each other at preferably the lowermost point X of the ring and then ,diverge away from the ring at the said lowermost point X. The rightand left-hand ends 7 and 9 of the terminal portions 3 and 5 of the envelope 1 are sealed so that the envelope may contain a gaseous medium of any desired nature, such, for example, as is described in the said Letters Patent. An anode principal electrode 11 is shown disposed within the envelope 1 in the terminal portion 3 near the end 7 thereof, and a principal cathode electrode 13 is similarly shown supported near the end 9 of the terminal portion 5. Each of the principal electrodes 11 and 13 is supported ,at points within the respective terminal portions 3 and 5 of the flashtube '1 outside the closed ring thereof by

rigid conductors

15 and 17 that extend through the sealed ends 7 and 9 of the terminal portions 3 and 5. The cathodeelectrode 13 may be of the sintered type, such as is described in United States Letters Patent No. 2,492,142 issued December 27, 1949, to Kenneth J. Germeshausen, though other types of cathodes may, of course, also be employed. The anode 11 similarly may be of any desired conventional type such as, for example, the type described in any of the said Letters Patent,

In accordance with a preferred embodiment of the invention, the

conductors

15 and 17 are connected by preferably flexible conductive extensions 19 and 21 to

electrical connectors

23 and 25. The

connectors

23 and 2 5 are preferably rigid elements, such as jacks, mounted upon

bands

27 and 29 that may be disposed about the terminal portions 3 and 5 of the envelope' l, preferably at positions between the locations of the principal electrodes '11 and 13 and the respective sealed ends 7 and 9. The

jacks

23, 25 extend from the

bands

27, 29, in the same direction away from and substantially perpendicular to the plane of the ring of the envelope 1, shown to the left in Figs. 1 and 3.

The light-wave reflector 2, which is preferably of substantially paraboloidal shape, is provided with apertures 31 that may contain insulating gaskets 33, as of rubber or similar material, for receiving the terminal portions of the

jack connectors

23 and 25. In Fig. 1, for example, the terminal portion 35 of the jack connector 25 is shown received within the apertured gasket 33. A collar 37 upon the jack 25 serves to limit the degree of insertion of the terminal portion 35 of the jack 25 within the apertured gasket 33, thus controlling the distance of the terminal portion of the flashtube 1 from the reflector 2. The jack 23 associated with the other terminal portion 3 of the flashtube 1 is similarly inserted within a similar gasket 33 at another point in the reflector 2.

In the case of three-electrode flashtubes, above mentioned, that are provided with a third or trigger electrode of any desired type, such as the external band electrode 39 disposed at a point substantially diametrically opposite to the point X of the ring of the envelope 1, the trigger electrode itself may serve as a mechanical supporting structure for a third electrical connector jack 41. The connector 41 may be similar in all respects to the

jack connectors

23 and 25, before described, and may be received in a similar apertured gasket 33 at a third point in the reflector. In order to provide optimum mechanical rigidity to such a three-point suspension as is 7 established by the

connectors

23, 25 and 41 of the flashtube 1, it is preferable that imaginary lines joining the three

connectors

23, 25 and 41 and the corresponding apertured gaskets 33 of the reflector 2 be disposed at the vertices of a substantially equilateral triangle, having an angle of 60 degrees, as shown in dashed lines in Fig. 2. As before stated, the use of the collars on the jack connectors, such as the collar 37 of the jack 25, and connectors of appropriate lengths, permit exact locating of the flashtube 1 in the focal plane, or in any other desired position, with respect to the concave side of the reflector 2. The tube 1 may thus be easily attached or mounted upon the reflector 2 with the assurance that the tube 1 is always place-i at the exact desired location and is rigidly mounted upon the reflector 2, without the necessity for fine adjustments.

Electric connections between the connector jacks and the desired flash-producing circuit may be provided on the convex side of the reflector 2. In Fig. 1, for example, a flash condenser or capacitor 4 may be connected by a wire conductor 6 to the end of the terminal portion 35 of the jack connector 25, as by a solder connection at the joint 8. Where a temporary and not a permanent connection is desired, the conductor 6, on the other hand, may be provided with a female type of connector 26, Fig. 5, for receiving the terminal portion 35 of the jack 25. Other types of electric-connector devices may similarly be employed. The lower terminal of the capacitor 4 is connected by a conductor 10 to the terminal portion of the jack 23. The flash condenser or capacitor 4 receives its voltage from any desired source of energy, such as a battery 12, that may be connected to charge the flash condenser 4 through a charging impedance 14 upon the closure of a power switch S. The voltage accumulated upon the charged capacitor 4 is therefore applied by the conductors 6 and 10, the

respective jacks

25 and 23, and the respective conductors 21-17 and 19-15 to the respective principal electrodes 13 and 11 of the flashtube 1. The voltage to which the condenser 4 is charged from the source 12, however, is preferably not of itself high enough to permit a discharge to take place in the gaseous medium of the envelope 1 between the cathode 13 and the anode 11. It is preferably necessary, to the contrary, to utilize the trigger electrode 39 to break down the gaseous medium in order that the condenser 4 may thereupon discharge its voltage between the cathode 13 and the anode 11 through the ring of the tube 1, thereby to produce a flash of light. This triggering may be eflected with the aid of a step-up triggering transformer 16, the upper terminal of the secondary winding 18 of which is connected by a conductor 20 to the jack 41, and thus to the trigger electrode 39. The lower terminal of the secondary winding 18 may be connected to the conductor 6. Any desired trigger device 22 may apply a voltage impulse in the primary winding 24 of the trigger transformer 16 in order to induce in the secondary winding 18 a triggering impulse that is applied by the

conductors

20 and 6 between the trigger electrode 39 and the cathode 13 of the flashtube 1, thereby to initiate the discharge of the condenser 4 between the cathode 13 and the anode 11. The triggering device 22 may be of any well-known type, including mechanical switching devices or electronic triggering circuits as disclosed, for example, in the before-mentioned Letters Patent. Any other type of flash-producing circuit may similarly be employed with the tube of the present invention.

In addition to providing for the accurate, rigid and simple mechanical positioning of the tube 1 with respect to the reflector 2, and for convenient electrical connections thereto, the present invention reduces materially the cost of manufacture of flashtubes. This is because it is merely necessary to loop the heated tubular material of the envelope into a single convolution or ring of any desired dimensions, including very small-sized rings, with the terminal portions crossing, to seal the principal electrodes and the gas within the tube, and then to utilize simple external mounting devices with jack or other connectors which can easily and inexpensively be mounted external to the envelope 1. The simplified tube construction and the attachment and detachment features of the present invention, moreover, render the same particularly useful in portable flash-photography apparatus where limited weight and size requirements are imposed and where it is also important that the operator be able to replace flashtubes rapidly without careful adjustments.

If desired, the crossing of the terminal portions of the envelope 1 at point X may be effected in the manner illustrated in Figs. 1 to 3, with the terminal portions 3 and 5 slightly diverging, also, out of the plane of the ring, as more particularly shown in Fig. 3. The cross-over, on the other hand, may be effected as in Fig. 4 with, for

. example, the terminal portion 3 lying substantially in the plane of the ring and the terminal portion 5 extending to one side of the said plane, to the right, as shown in Fig. 4. Further modifications will occur to those skilled in the art and all such are considered to fall within the spirit and scope of the invention as defined in the appended claims.

What is claimed is:

1. An electric-discharge device having, in combination,

- a tubular gas-filled envelope looped into a single closed ring with the terminal portions crossing at a predetermined point along the ring and diverging from the said point away from the ring, and a pair of electrodes mounted within the envelope at the said diverging terminal portions.

2. An electric-discharge device having, in combination, a tubular gas-filled envelope looped into a single closed ring with the terminal portions crossing at a predetermined point along the ring and diverging from the said point away from the ring, a pair of electrodes mounted within the envelope at the said diverging terminal portions, and an electrical connector connected to each of tions, and a third electrode positioned at a point of the ring displaced from the said predetermined point.

4. An electric-discharge device having, in combination, a tubular gas-filled envelope looped into a single closed ring with the terminal portions crossing at a predetermined point along the ring and diverging from the said point away from the ring, a pair of electrodes mounted within the envelope at the said diverging terminal portions, a third electrode positioned at a point of the ring displaced from the said predetermined point, and an electrical connector connected to each of the electrodes and mounted to extend in the same direction away from and substantially perpendicular to the plane of the ring.

5. An electric-discharge device having, in combination, a tubular gas-filled envelope looped into a single closed ring with the terminal portions crossing at a predetermined point along the ring and diverging from the said point away from the ring, a pair of electrodes mounted within the envelope at the said diverging terminal portions, a third electrode positioned at a point on the ring disposed substantially opposite to the said predetermined point, and an electrical connector connected to each of the electrodes and mounted to extend in the same direction away from and substantially perpendicular to the plane of the ring, the electrical connectors forming the vertices of a substantially equilateral triangle.

6. A flashtube having, in combination, a light-transparent tubular envelope looped into a single closed ring with the terminal portions crossing at a predetermined point along the ring and diverging from the said point away from the ring, the envelope being sealed at the ends of the terminal portions and containing a gaseous medium, and a pair of electrodes mounted within the gaseous medium at the said diverging terminal portions of the envelope and provided with conductors extending through the said sealed ends outside the envelope.

7. A flashtube having, in combination, a light-transparent tubular envelope looped into a single closed ring with the terminal portions crossing at a predetermined point along the ring and diverging from the said point away from the ring, the envelope being sealed at the ends of the terminal portions and containing a gaseous medium, a pair of electrodes mounted within the gaseous medium at the said diverging terminal portions of the envelope and provided with conductors extending through the said sealed ends outside the envelope, and an electrical connector connected to each of the said conductors outside the envelope and mounted to extend in the same direction away from and substantially perpendicular to the plane of the ring.

8. A flashtube having, in combination, alight-transparent tubular envelope looped into a single closed ring with the terminal portions crossing at a predetermined point along the ring and diverging from the said point away from the ring, the envelope being sealed at the ends of the terminal portions and containing a gaseous medium, apair of electrodes mounted within the gaseous medium at the said diverging terminal portions of the envelope and provided with conductors extending through the said sealed ends outside the envelope, a third electrode positioned at a point of the ring displaced from the said predetermined point, and an electrical connector con nected outside the envelope to each of the said conductors and to the third electrode and mounted to extend in the same direction away from and substantially perpendicular to the plane of the ring.

9. A flashtube having, in combination, a light-transparent tubular envelope looped into a single closed substantially circular ring with the terminal portions crossing at a predetermined point along the ring and diverging from the said point away from the ring, the envelope being sealed at the ends of the terminal portions and containing a gaseous medium, a pair of electrodes constituting an anode and a cathode mounted within the gaseous medium at the said diverging terminal portions of the envelope and provided with conductors extending through the said sealed ends outside the envelope, a trigger electrode disposed outside the envelope at a point of the ring disposed substantially diametrically opposite to the said predetermined point, and an electrical connector connected outside the envelope to each of the said conductors and to the trigger electrode and mounted to extend in the same direction away from and substantially perpendicular to the plane of the ring, the electrical connectors forming the vertices of a substantially equilateral triangle.

10. A flashtube having, in combination, a light-transparent tubular envelope looped into a single closed substantially circular ring with the terminal portions crossing at a predetermined point along the ring and diverging from the said point away from the ring, the envelope being sealed at the ends of the terminal portions and containing a gaseous medium, a pair of electrodes constituting an anode and a cathode mounted within the gaseous medium at the said diverging terminal portions of the envelope and provided with conductors extending through the said sealed ends outside the envelope, a trigger electrode disposed outside the envelope at a point of the ring disposed substantially diametrically opposite to the said predetermined point, bands mounted about the out side of the said terminal portions and connected with the said conductors, and an electrical jack connector having a limiting flange connected to and mounted upon each of the bands and the trigger electrode and extending in the same direction away from and substantially perpendicular to the plane of the ring, the electrical connectors forming the vertices of a substantially equilateral triangle.

11. A flashtube as claimed in claim 8 and in which the said terminal portions diverge, also, from the said plane of the ring.

12. A flashtube as claimed in claim 8' and in which one of the said terminal portions lies substantially in the said plane of the ring and the other terminal portion extends to one side of the said plane.

13. Flashtube apparatus having, in combination, a substantially paraboloidal reflector provided with three insulated apertures disposed substantially at the vertices of an equilateral triangle surrounding the vertex of the reflector; a flashtube comprising a light-transparent tubular envelope looped into a single closed ring with the terminal portions crossing at a predetermined point along the ring and diverging from the said point away from the ring, the envelope being sealed at the ends of the terminal portions and containing a gaseous medium, a pair of electrodes constituting an anode and a cathode mounted within the gaseous medium at the said diverging terminal por tions of the envelope and provided with conductors extending through the said sealed ends outside the envelope, a trigger electrode disposed outside the envelope at a point of the ring disposed substantially opposite to the said predetermined point, and an electrical connector connected outside the envelope to each of the said conductors and to the trigger electrode and mounted to extend in a direction substantially perpendicular to the plane of the ring toward the concave side of the said reflector, the electrical connectors forming the vertices of substantially the same equilateral triangle in order that they may be received in the insulated apertures of the reflector to mount the flashtube substantially in the focal plane of the reflector; and electrical conductors disposed on the convex side of the reflector for connecting a source of energy between the two electrical connectors connected to the said anode and cathode and a trigger circuit to the electrical connector connected to the trigger electrode, thereby, upon operation of the trigger circuit, to permit the source of energy to produce a flash-discharge in the gaseous medium around the said ring between the anode and the cathode, the illumination of which is directed into space by the reflector.

14. Electric-discharge apparatus having, in combination, a substantially paraboloidal reflector provided with a plurality of apertures; an electric-discharge device comprising a tubular gas-filled envelope looped into a single closed ring with the terminal portions crossing at a predetermined point along the ring and diverging from the said point away from the ring, a pair of electrodes mounted within the envelope at the said diverging terminal portions, a third electrode positioned at a point of the ring displaced from the said predetermined point; and an electrical connector connected to each of the electrodes and mounted to extend toward the concave side of the reflector, the electrical connectors being disposed to be received by the reflector apertures in order to mount the electric-discharge apparatus in substantially the focal plane of the reflector, electrical connections to the electricdischarge device being established with the said electrical connectors at the convex side of the reflector.

15. An electric-discharge device having, in combination, a tubular gas-filled envelope looped into a single closed ring with the terminal portions crossing at a predetermined point along the ring and diverging from the said point away from the ring, a pair of electrodes mounted within the envelope at the said diverging terminal portions, a third electrode positioned at a point on the ring disposed substantially opposite to the said predetermined point, and an electrical connector disposed adjacent to and connected to each of the electrodes and mounted to extend in the same direction away from and substantially perpendicular to the plane of the ring, the electrical connectors forming the vertices of a substantially equilateral triangle.

16. A flashtube having, in combination, a light-transparent tubular envelope looped into a single closed substantially circular ring with the terminal portions crossing at a predetermined point along the ring and diverging from the said point away from the ring, the envelope being sealed at the ends of the terminal portions and containing a gaseous medium, a pair of electrodes constituting an anode and a cathode mounted within the gaseous medium at the said diverging terminal portions of the envelope and provided with conductors extending through the said sealed ends outside the envelope, a trigger electrode disposed outside the envelope at a point of the ring disposed substantially diametrically opposite to the said predetermined point, and an electrical connector adjacent each electrode and connected outside the envelope to each of the said conductors and to the trigger electrode and mounted to extend in the same direction away from and substantially perpendicular to the plane of the ring, the electrical connectors forming the vertices of a substantially equilateral triangle.

17. A flashtube having, in combination, a light-transparent tubular envelope looped into a single closed substantially circular ring with the terminal portions crossing at a predetermined point along the ring and diverging from the said point away from the ring, the envelope being sealed at the ends of the terminal portions and containing a gaseous medium, a pair of electrodes constituting an anode and a cathode mounted within the gaseous medium at the said diverging terminal portions of the envelope and provided with conductors extending through the said sealed ends outside the envelope, a trigger electrode disposed outside the envelope at a point of the ring disposed substantially diametrically opposite to the said predetermined point, bands mounted about the outside of the said terminal portions adjacent the pair of electrodes and connected with the said conductors, and an electrical jack connector having a limiting flange connected to and mounted upon each of the bands and the trigger electrode and extending in the same direction away from and substantially perpendicular to the plane of the ring, the electrical connectors forming the vertices of a substantially equilateral triangle.

18. Flashtube apparatus having, in combination, a sub stantially paraboloidal reflector provided with three insulated apertures disposed substantially at the vertices of an equilateral triangle surrounding the vertex of the reflector; a flashtube comprising a light-transparent tubular envelope looped into a single closed ring with the terminal portions crossing at a predetermined point along the ring and diverging from the said point away from the ring, the envelope being sealed at the ends of the terminal portions and containing a gaseous medium, a pair of electrodes constituting an anode and a cathode mounted within the gaseous medium at the said diverging terminal portions of the envelope and provided with conductors extending through the said sealed ends outside the envelope, a trigger electrode disposed outside the envelope at a point of the ring disposed substantially opposite to the said predetermined point, and an electrical connector connected outside the envelope adjacent each electrode and to each of the said conductors and to the trigger electrode and mounted to extend in a direction substantially perpendicular to the plane of the ring toward the concave side of the said reflector, the electrical connectors forming the vertices of substantially the same equilateral triangle in order that they may be received in the insulated apertures of the reflector to mount the flashtube substantially in the focal plane of the reflector; and electrical conductors disposed on the convex side of the reflector for connecting a source of energy between the two electrical connectors connected to the said anode and cathode and a trigger circuit to the electrical connector connected to the trigger electrode, thereby, upon operation of the trigger circuit, to permit the source of energy to produce a flash-discharge in the gaseous medium around the said ring between the anode and the cathode, the illumination of which is directed into space by the reflector.

l9. Electric-discharge apparatus having, in combination, a substantially paraboloidal reflector provided with a plurality of apertures; an electric-discharge device comprising a tubular gas-filled envelope looped into a single closed ring with the terminal portions crossing at a predetermined point along the ring and diverging from the said point away from the ring, a pair of electrodes mounted within the envelope at the said diverging terminal portions, a third electrode positioned at a point of the ring displaced from the said predetermined point; and an electrical connector disposed adjacent to and connected to each of the electrodes and mounted to extend toward the concave side of the reflector, the electrical connectors being disposed to be received by the reflector apertures in order to mount the electric-discharge apparatus in substantially the focal plane of the reflector, electrical connections to the electric-discharge device being established with the said electrical connectors at the convex side of the reflector.

References Cited in the file of this patent UNITED STATES PATENTS 755,307 Moore Mar. 22, 1904 966,203 Hewitt Aug. 2, 1910 1,820,027 McClintock Aug. 25, 1931 1,950,445 Braselton Mar. 13, 1934 2,160,786 Peterson May 30, 1939 2,200,940 Uyterhoeven et al May 14, 1940 2,209,052 Corlburg July 23, 1940 2,211,605 Moehler Aug. 13, 1940 2,392,828 Noel Jan. 15, 1946 2,477,340 Makenny July 26, 1949 2,549,330 Noel Apr. 17, 1951