Aug. 16, 1949. H. E. EDGERTON 2,478,908 ELECTRIC LIGHT-FLASH-PRODUCING SYSTEM Filed Feb. 11, 1946 3 Sheets-Sheet li

Aug. 16, 1949. H. E. EDGERTON 2,478,908 ELECTRIC LIGHT-FLASH-PRODUCING SYSTEM Filed Feb. ll, l946 3. Sheets-Sheet 2

HAROLD E. E. DGERTON INVENTOR. Aug. 16, 1949. H. E. EDGERTON 2,478,908 ELECTRIC LIGHT-FLASH-PRODUCING SYSTEM Filed Feb. ll, 1946 3. Sheets-Sheet 3

? :

HAROLD E. EDGERTON. INVENTOR.

Patented Aug. 16, 1949 2.478,908 UNITED STATES PATENT OFFICE . 2,478,90s ELECTRIC LIGHT-FILAS -PRODUCING SYSTEM Harold E. Edgerton, Belmont, Maas. - Application February 11, 1946, serial No. 646,781. 5 Claims. (CL177-329). 1. The present invention relates to electric sys tion: Fig. 2 is a fragmentary perspective, with tems, and more particularly to flash-producers. parts broken away; Fig. 3 is a view of one of the From a more specific aspect, the invention relates flash-lamps, the reflector in which it is mounted to flash-producing beacons, such as are used at being shown in longitudinal. section; Fig. 4 is a airfields to signal or otherwise attract the atten diagrammatic view of circuits and apparatus em tion of aviators in airplanes. The invention is bodying the invention, in preferred form; and in the nature of an improvement upon the system Fig. 5 is a similar view of a modification. disclosed in a copending application, Serial No. According to the specific embodiments of the 510,984, filed November 19, 1943, now Patent No. invention that are herein illustrated and de 2,449,063, of September 14, 1948. 0. scribed, a number of flash-lamps 8 are spaced In the said application, there is disclosed a uniformly over the beacon throughout the 360 beacon employing a number of flash-lamps, ar degrees of azimuth. The invention is applicable ranged according to a predetermined configura to other configurations also. In the illustrated tion, and illuminated rapidly, in predetermined configuration, however, the flash-lamps 8 are Sequence or succession, by discharging a high 5 disposed along a circular row in a horizontal tension condenser through them rapidly in pre plane, within a housing having a cylindrical trans determined sequence or succession. As all the parent wall f, at the top of a beacon support 8. energy of the discharge condenser is thus ex Each flash-lamp is mounted in a reflector 25 for pended, at any particular time, in producing a directing the light of that particular flash-lamp flash, high-intensity flashes are thus produced 20 along a particular direction of azimuth. The for very short periods of time. The energy of flash from the lamp positioned at A, for example, the condenser is replenished by recharging it may be directed South, in which event the flash before each discharge thereof. The number of from the lamp positioned diametrically opposite, flash-lamps is sufficiently large and the flashing at B, may be directed north. The flashes from is sufficiently rapid to give the illusion of a beam 25 the lamps positioned at C and D may similarly of light traveling rapidly from flash-lamp to flash be directed east and west, respectively. Two lamp following the predetermined configuration. flash-lamps positioned at E and F, on opposite There are cases, however, where it is not de sides of, and adjacent to, the flash-lamp posi sirable to be compelled to discharge the same tioned at A, will direct flashes in corresponding high-tension condenser through all the flash 30 directions: the lamp positioned at E will direct lamps, even though this is effected in predeter a flash between south and south-east, and the mined sequence: or succession, and not simulta lamp positioned at F will direct its flash between neously. . - south and south-west. The lamp positioned at . . According to the present invention, the limita G will produce a flash in a direction between east tions mentioned are overcome by arranging for and south-east, and the lamp positioned at H in the discharge of a separate condenser through a direction between west and south-west. The each separate flash-lamp. Although the use of lamps positioned at J, K, L, and M will send their separate condensers on individual lamps will in flashes in directions opposite to the directions of volve more apparatus, the following advantages flash of the lamps positioned at G, E, F and H, are attained: 40 respectively. As many lamps as desired may be First, the entire beacon will not be extinguished provided, each with a reflector for directing the flash in a particular direction of azimuth. It is in case of the failure of one of the flash con convenient to employ also a further flash-lamp, densers.Second, the use of separate discharge Con shown positioned at I, for directing its flash up densers allows more time for the charging cycle. 45 ward through a transparent portion 32 of the . This may be important when it is desired to oper upper wall 33 of the housing at the top of the ate the beacon at a high flashing speed. support 8. This lamp is particularly useful in Furthermore, efficient flash tubes require time foggy weather. for deionization, and this is provided in a charg Each flash-lamp 8 is of the gaseous-discharge ing circuit that builds up the condenser voltage 50 type. The flashes through the separate flash at the minimum rate. - lamps 8 are produced by discharging there The invention will now be more particularly through the electric energy stored in separate explained in connection with the accompanying high-tension dielectric electric-energy-storage drawings, in which Fig. 1 is a diagrammatic ele means or flash condensers, several of which flash vation of a beacon embodying the present inven 55 condensers are shown at , f and 2. The 2,478,908 3 n 4. number of separate flash-lamps 8 is equal to The flash-lamp 8 is shown provided with a the number of separate flash condensers. Each cathode 7 and an anode 9, respectively connected separate condenser corresponds to one and one to the terminals 6 and 2. A high-voltage-spark only of the separate flash-lamps, and each sepa trigger or trip wire control starting electrode 22 rate flash-lamp corresponds to one and One only is connected to the terminal f. of the separate condensers. The condensers con The voltage to which the condensers , , - - - stitute the principal sources of energy for effect 2 are subjected by the direct-current voltage ing the discharge of their corresponding flash Supply before each discharge thereof is insufi lamps 8; they are first charged and then dis cient to cause these condensers to discharge be charged through their corresponding flash-lamps O tween the cathodes 7 and the anodes 9 through 8 rapidly, in predetermined sequence or succes the normally non-conductive flash-lamps 8, sion. Surges of current are thus caused to flow when non-conductive, notwithstanding the con rapidly, in predetermined sequence or succession, nection of the condensers to the flash-lamps 8. through the flash-lamps 8. Each Surge of cur The flash-lamps 8 are rendered conductive, how rent produces a flash of high intensity in the ever, to control these discharges under the control corresponding flash-lamp 8, followed by prompt of the starting electrodes 22. The starting elec extinguishment of that lamp 8 and the fashing trodes 22, in turn, may be energized in any desired of the next flash-lamp f8, in predetermined se manner, as by. means of normally ineffective quence or succession. Each flash-lamp 8 is thus trigger-discharge circuits operable, when effec rendered momentarily luminescent, to produce a tive, to render the flash-lamps 8 conductive irre flash, by the discharge of its corresponding con Spective of the state of charge of the condensers. denser therethrough. . This will now be explained. - . Assuming, for example, that the flash-lamp In Order that it may discharge through its cor positioned at C is the first to flash, the next lamp responding flash-lamp 8 when conductive, and to flash will be that positioned at G, then the through no other flash-lamp 8, each discharge lamp positioned at E, then the lamps positioned condenser is connected to its corresponding flash at A, F, H, D, J, K, B, L, and M. The lamp posi lamp 8 and its corresponding flash-lamp 8 only. tioned at I will finally be flashed, after which the To the attainment of this end, the cathode 7 and other lamps will be again flashed in succession, the anode 9 of each flash-lamp 8 are connected in the same Order. through the medium of its terminal pins 6 and 2 Let it be assumed that the incoming aviator is across its corresponding discharge condenser and directly south of the beacon, and at a consider to no other discharge condenser. The terminal able distance therefrom. He may, in that event, pins 2 are connected to a grounded terminal 15, observe at least the flash from the lamp positioned at one side of the respective storage condensers at A. That single flash alone will guide him to , , - - - 2, by respective conductors 3, the airport. By reason of the fact that the whole 3f, - - - 23, through charging resistors 35, energy of the particular condenser is concen 35, - - - 235, and the terminal pins 6 are con trated, at the time of the flash, in that one lamp, nected to a terminal 3, at the other side of the the flash will be of considerable intensity, with condensers, by a common conductor 29. the result that he may see it at a very great 4) The electric-energy-storage condensers may be distance. Subjected to a voltage of, say, 2000 volts, from As he approaches closer, the flash from the any direct-current supply. The preferred supply lamp positioned at A will become more intense, is shown as a transformer 26, the primary wind and he may begin to see also, though with less ing 28 of which may be connected to any desired intensity, the flashes from the lamps positioned . Source of alternating energy of suitable voltage at E and F. As he comes closer still, he may see and frequency, and the secondary winding 30 of the flashes of other lamps also, say the lamps which may be connected to each of the condensers positioned at G and H. through a full-wave rectifier 72. This conven The same remarks apply no matter from what iently provides a supply of pulsating current for direction the aviator arrives. There will always 50 charging the condensers. The secondary winding be at least one lamp flashing along his direction, 30 may have a high impedance for performing or nearly so, with the greatest intensity, and per the normal current-limiting function of a charg haps other lamps flashing in slightly different ing impedance. directions with less intensity. The charging resistors 35, 35, - - - 235, con The successive flashing of the lamps along dif nected, at one side, to the respective terminal ferent directions of azimuth, moreover, gives the pins 2, and, at the other side, to the grounded illusion of a rotating beam of light, but without terminal 5 of the full-wave rectifier T2, serve to the necessity for employing moving parts. The isolate the respective discharge condensers , same applies to any other configuration, the na , - - - 2. The condensers , f f, - - - 2 are ture of the illusion of the beam of light traveling 60 thus connected in parallel to the terminals 3 from flash-lamp to flash-lamp depending upon and 5, at opposite sides of the direct-current the nature of the configuration. energy supply, through their respective isolating The preferred gaseous-discharge flash-lamp 8 charging resistors 35, 35,235. may contain xenon or other suitable gas. It is A motor 34 is illustrated as the motive power for shown mounted in an elongated light-permeable 65 driving a commutator switch, having as many glass-bulb jacket or envelope 92, which is shown commutating cams 39, 40, - - - 6, or 39, 40, - - - cemented at 24 to a flat insulating base 94, pro-. 6, as there are flash-lamps f8 to be flashed. vided with three terminal pins 6, 2 and 4 pro The commutating cam 39 is designed to close jecting exteriorly thereof. a switch 62, the cam 40 a switch 63, and the The reflector 25 is mounted upon the base 94. 70 cam 6 a switch 64. The commutating cams 39, It may, for example, concentrate the light into a 40, - - - 6 are similarly designed to close COne of approximately 30 degrees. Light So con switches 62, 63, - - - 64. These switches will centrated would be visible at a greater distance become momentarily closed, in predetermined than the light from the same lamp without a sequence or Succession, by the corresponding reflector. 75 cams, in response to the operation of the motor are,00s 5 shown connected across the condenser 8, in series 34, and then will become reopened. The switches may be of the snap or toggle variety so that they with the switch 64. Each condenser 4, 42, - - - 43 may close with a positive action, to insure good is thus connected in its discharge circuit with the contact in a short interval of time. primary winding of its transformer. Similar con “In the system of Fig. 5, condensers 4, 42, - - - 5 nections to the additional flash-lamps f, not 43 are shown connected in respective trigger-dis shown, will be made through similar transformers, charge circuits to the terminals 3 and 15, in not shown. parallel with the condensers f, f, - - -2, by 'According to the preferred embodiment of the conductors 5 and 5. A resistor 58 is shown con invention shown in Fig. 4, however, the condensers nected by the conductors 5 and 57 in series with 10 4, 42, - - - 43 are connected to the respective pri the condenser 4, a resistor 59 in series with the mary windings 74, 47, - - - 54 by means of trigger condenser 42, - - - a resistor 60 in series with the ing circuits comprising normally non-conducting condenser 3. and therefore ineffective, thyratrons or other In the system of Fig. 4, however, the correspond gaseous-discharge trigger tubes if, fol, - - - 02, ing condensers 4, 42, - - - 43 are shown con 5 connected in series with the condensers 4, 42, - - - nected by the conductors 5 and 57 across a 43 and with the primary windings 74, 47, ---.54. common impedance, shown as the portion 8 of a A preferred trigger tube may be of the cold bleeder resistor. One end of the bleeder-resistor cathode gaseous-discharge type illustrated and portion 8 is connected to the terminal 3, and described in Letters Patent 2,185,189,2,201,166 and the other end, through a portion 8 of the bleeder 20 2,201,167, issued to Kenneth J. Germeshausen on resistor, to the grounded terminal 5. The January 2 and May 21, 1940. It may comprise an bleeder-resistor portions 8 and 8 are thus con evacuated glass envelope containing several elec nected in series across the direct-current pulsat trodes, namely, a solid cold cathode 2, an anode or ing-energy supply 26, 72. The condensers 4, plate 5 and one or more control electrodes 3. With 42, - - - 43 of Fig. 4 are therefore supplied with 5 tubes of this type, the current required by the voltage, to store electric energy therein, ultimately switches 62,--- f63, G4 becomes negligible, and from the same direct-current-power supply that wear due to arcing is thereby reduced, so that long charges the condensers ff, ?, - - - 2. In the life is enjoyed. An impedance 95 is shown con system of Fig. 5, the condensers , , - - - 2 nected between the cathode 2 and the control are all connected to the direct-current source by 30 electrode 3. ". way of the terminals 3 and 5. In the system of The discharge circuits of the condensers 4, 42, Fig. 4, the condensers , , - - - 2 f are so con - - - 43 thus contain the respective tubes , o, . nected, but the condensers 4, 42, - - - 43 are Sup - - - 02 and the respective primary windings. plied with voltage from the bleeder resistor 8, These tubes , o, - - - fo2 may be operated in which constitutes their main power supply. 3 5 Succession, in response to the closing of the The condensers , , - - - 2 may be dis switches 62, 63 and 64, respectively, as herein charged through their respective discharge tubes after more fully described, to discharge through 8, as more fully explained hereinafter, by means the respective primary windings 73, 47, - - - 54, of the before-mentioned trigger circuits. The thereby to flash their respective flash-lamps 8 motor-driven commutator switch effects a cur 40 at the desired instants. . rent flow through the separate trigger circuits, in In operation, in the systems of both Figs. 4 and predetermined sequence, to energize the triggering . 5, the condenser starts to become charged from transformers in succession, thus to energize the the direct-current source 26, 2. The tube is trigger electrodes 22 of the flash-lamps 8 in suc at this time non-conductive. The condenser 4 cession. Hight-voltage separate triggering sparks becomes charged, at the same time, through the are thus produced to effect a discharge of the re resistor 8 and the primary winding 74. In the spective electric-energy-storage condensers l, System of Fig. 4, upon the momentary closing of ff, - - - 2 through the corresponding lumines the switch 62, by the commutator cam 39, the cent-discharge devices 8, in Succession. This is potential of the control electrode 3 of the tube effected through the medium of separate trigger becomes raised until the breakdown voltage be ing transformers, three of which are shown at 36, tween the control electrode 3 and the cathode 2 46 and 56. Each lamp 8 is provided with one is exceeded, whereupon the trigger tube be such triggering transformer. The transformer 36 comes conducting. The condenser 4, which has is shown provided with a primary winding 74 and previously become charged from the rectifier a secondary winding 38; the transformer 46 with 5 5 Supply 26, 72 of pulsating current, then dis a primary winding 47 and a secondary winding charges through the previously-described trigger 48; - - - and the transformer 56 with a primary Condenser-discharge circuit comprising the tube winding 54 and a secondary winding 55. One side and the primary winding 74. The same dis of each of the secondary windings 38, 48, - - - 55, charge of the condenser 4, through the primary is connected to the terminal 3 by the conductor 60 winding 74, takes place in the system of Fig. 5 29. The other sides of the secondary winding 38, - upon the momentary closing of the switch 62 by 48, - - - 55 are respectively connected to the termi the commutator cam 39. In both systems, the nals 4 of the triggering starting electrodes 22. A resulting voltage-surge pulse of the secondary separate trigger circuit is thus provided for each winding 38 of the transformer 36 will thereupon control electrode 22. become applied to energize the trigger electrode The connections of the primary windings of the 22 of the corresponding flash tube 8; this trip transformers are not the same in the Systems of ping of the trigger-discharge circuit for the con Figs. 4 and 5. Referring first to Fig. 5, the denser 4 will cause the gas in the corresponding primary winding 74 of the transformer 36 is shown flash-lamp 8 to become ionized, producing a connected across the condenser 4, in Series with 70 conducting path through the corresponding the switch 62, by a conductor 9 f; the primary luminescent-discharge device 8, and permitting winding 47 of the transformer 46 is similarly the condenser f to discharge therethrough, be shown connected across the condenser 42, in tween the cathode and the anode 9 thereof. series with the switch 63; - - - and the primary The resulting high-voltage discharge through winding 54 of the transformer 56 is similarly 75 this lamp 18 will produce a very brilliant flash of 9478,908 7 . light of short duration. When the condenser in response to the discharge of electric energy becomes fu'y discharged, this lamp 8 becomes therethrough when conductive, each separate extinguished, and the condenser again be condenser corresponding to one and one only of comes charged from the rectifier supply 26, 2 of the separate flash-lamps and each separate flash pulsating current, prior to its next discharge 5 lamp corresponding to one and One only of the sep through its flash-lamp 8. arate Condensers, means connecting each con The switch 63 or 63 becomes thereafter no denser to its corresponding flash-lamp and its mentarily closed, to effect a similar discharge, in corresponding flash-lamp only to discharge it similar manner, of the condenser 42 through the through its corresponding flash-lamp when con primary winding 47 of the transformer 46. The 10 ductive and through no other flash-lamp, means secondary winding 48 of the transformer 46 will for charging each condenser, and means for ren thereupon similarly energize the starting elec dering the flash-lamps conductive rapidly in pre trode 22 of the next lamp 8 to be flashed. This determined sequence to discharge the condensers next lamp 8 will become flashed by the sepa through their corresponding flash-lamps rapidly rate condenser if discharging therethrough. in predetermined sequence, thereby to cause the Upon the extinguishment of this next lamp 18, flash-lamps to produce light flashes rapidly in the next commutating cam will effect the closing predetermined sequence, the number of flash of the next switch; and so on, until the last can lamps being sufficiently large and the operation 6 or 6 operates the last switch 64 or 64, of the rendering means being sufficiently rapid whereupon the last condenser 43 will discharge 20 to give the illusion of a beam of light traveling through the primary winding 54 of the trans rapidly from flash-lamp to flash-lamp following former 56. The secondary winding 55 will there the predetermined configuration. upon effect a discharge of the last condenser 2 3. A light-flash-producing system having, in through the last lamp 8, thus causing the flash combination, a circuit including a plurality of ing of this last lamp 8. Separate condensers and an equal number of sepa The control electrodes 22 will also become en rate normally non-conductive flash-lamps ar ergized, in very rapid succession, in this manner, ranged according to a predetermined configura to cause the flash-lamps 8 to become flashed tion and each adapted to produce light flashes in very rapidly in succession, as before described. response to the discharge of electric energy there The flashing cycle will then recommence. 30 through when conductive, each separate condens Instead of employing the switches 62, 63, - - - er corresponding to one and one only of the sepa 64, the tubes , Ol, - - - 102 may be controlled rate flash-lamps and each separate flash-lamp through the medium of well known electrical corresponding to one and one only of the sepa time-delay circuits for rendering each lamp re. rate condensers, means connecting each condens sponsible for starting the succeeding lamp after 5 er to its corresponding flash-lamp and its cor a predetermined time delay. The same sequence responding flash-lamp only to discharge it of flashing can be used for coding the beacon. through its corresponding flash-lamp when con For example, the flashes could be grouped in ductive and through no other flash-lamp, means numbers that would correspond to those as for charging each condenser before each discharge signed to the particular position. The coding 40 thereof to a voltage insufficient to cause it to dis scheme could be based on the time spacing of charge through its corresponding flash-lamp flashes. Further modifications will occur to perSons while non-conductive notwithstanding its con skilled in the art, and all such are considered to nection to its corresponding flash-lamp, normally fall within the spirit and scope of the present in ineffective means operable when effective to ren vention, as defined in the appended claims. der the flash-lamps conductive, and means for What is claimed is: rendering the normally ineffective means effective 1. A light-flash-producing system having, in . rapidly in predetermined sequence to render the combination, a circuit including a plurality of flash-lamps conductive rapidly in predetermined separate condensers and an equal number of sequence to discharge the condensers through separate normally non-conductive flash-lamps 50 their corresponding flash-lamps rapidly in pre each adapted to produce light flashes in response determined sequence, thereby to cause the flash to the discharge of electric energy therethrough lamps to produce light flashes rapidly in pre when conductive, each separate condenser COr- . determined sequence, the number of flash-lamps responding to one and one only of the separate being sufficiently large and the operation of the flash-lamps and each separate flash-lamp corre 55 rendering means being sufficiently rapid to give sponding to one and one only of the separate con the illusion of a beam of light traveling rapidly densers, means connecting each condenser to its from flash-lamp to flash-lamp following the pre corresponding flash-lamp and its corresponding . determined configuration. flash-lamp only to discharge it through its cor 4. A light-flash-producing system having, in responding flash-lamp when conductive and 60 combination, a circuit including a plurality of through no other flash-lamp, means for charg Separate condensers and an equal number of sep ing each condenser, and means for rendering arate normally non-conductive flash-lamps each the flash-lamps conductive rapidly in predeter adapted to produce light flashes in response to the mined sequence to discharge the condensers discharge of electric energy therethrough when through their corresponding flash-lamps rapidly 6 conductive, each separate condenser correspond in predetermined sequence, thereby to cause the ing to one and one only of the separate flash flash-lamps to produce light flashes rapidly in lamps and each separate flash-lamp correspond predetermined sequence. ing to one and one only of the separate condens ers, means connecting each condenser to its cor 2. A light-flash-producing system having, in 70 responding flash-lamp and its corresponding combination, a circuit including a plurality of flash-lamp only to discharge it through it cor separate condensers and an equal number of responding flash-lamp when conductive and Separate normally non-conductive flash-lamps through no other flash-lamp, means for charging arranged according to a predetermined configu each condenser, trigger-circuit means connected ration and each adpated to produce light flashes 75 to the flash-lamps, and means for rapidly trigger 2,478,908 10 ing the trigger-circuit means to render the flash means connecting, each trigger-circuit means to lamps conductive rapidly in predetermined se its corresponding flash-lamp and and its cor quence to discharge the condensers through their responding flash-lamp only to trigger its cor corresponding flash-lamps rapidly in predeter responding flash-lamp and no other flash-lamp, mined sequence, thereby to cause the flash-lamps and means for operating the separate trigger to produce light flashes rapidly in predetermined circuit means rapidly in predetermined sequence Sequence, to render the flash-lamps conductive rapidly in 5. A light-flash-producing system having, in predetermined sequence to discharge the con combination, a circuit including a plurality of densers through their corresponding flash-lamps separate condensers and an equal number of O rapidly in predetermined sequence, thereby to separate normally non-conductive flash-lamps cause the flash-lamps to produce light flashes arranged according to a predetermined config rapidly in predetermined sequence, the number of uration each adapted to produce light flashes in flash-lamps being sufficiently large and the oper response to the discharge of electric energy there ation of the separate trigger-circuit means being through when conductive, each separate condens 5 sufficiently rapid to give the illusion of a beam of er corresponding to one and ane only of the sepa light traveling rapidly from flash-lamp to flash rate flash-lamps and each separate flash-lamp lamp following the predetermined configuration. corresponding to one and one only of the sepa HAROL DE, EDGERTON. rate condensers, means connecting each condens er to its corresponding flash-lamp and its cor 20 REFERENCES CTED responding flash-lamp Only to discharge it The following references are of record in the through its corresponding flash-lamp when con file of this patent: ductive and through no other flash-lamp, means for charging each condenser before each dis UNITED STATES PATENTS charge thereof, separate trigger-circuit means 25 Number Name Date connected to the respective flash-lamps, each 1328,041 Fischer ------Jan. 13, 1920 separate trigger-circuit means corresponding to 2,327,971 Slepian ------Aug. 24, 1943 one and one only of the separate flash-lamps and 2,351,603 Edgerton ------June 20, 1944 each separate flash-lamp corresponding to one 2,355,349 Wheelock et al. ------Aug. 8, 1944 and one only of the separate trigger-circuit means, 30