Abstract: The time period necessary to charge a current-to-light convertible energy storing capacitor to a certain voltage is reduced as compared with prior art devices. The energy storing capacitor is connected across a flash tube and switching element series-connected with each other. The switching element is provided with a control circuit, responsive to the voltage of the storage capacitor decreasing to a level at which the flash tube is stopped from producing flash light, for producing a terminating signal by which the switching element is brought into the open or non conducting state. With this arrangement, it is made possible to prevent complete discharge of the electric charge stored in the storage capacitor from occurring, thereby providing the advantage of saving a good fraction of the charging time period which would be otherwise necessary when the storage capacitor is completely discharged to zero voltage.

Abstract: A circuit for igniting an electronic flashtube including a thyristor connected in series with the flashtube and an ignition capacitor connected through a switching thyristor to an ignition transformer to trigger the flashtube. The state of the series thyristor is controlled by means such as an electronic threshold switch to provide proper switching operation over a range of flashtubes with different specimen variations with respect to the time required to build up plasma.

Abstract: Series and shunt flashlamp triggering arrangements are disclosed wherein an electrically conductive patch is intimately bonded to a portion of the outer lateral surface of the flashlamp housing extending over a portion of the high voltage electrode and terminating at a longitudinal location along the housing substantially aligned with the inner end of the high voltage electrode. An electrically conductive wire connected to the patch extends along the outer lateral surface of the housing from the patch to at least the vicinity of the other electrode. The high voltage electrode defines a sharp-edged annular rim projecting outwardly from its lateral surface adjacent its inner end.

Abstract: A device for automatic control of the quantity of light from an electronic flash tube including a silicon controlled rectifier connected in series with the flash tube, a circuit for applying a reverse voltage between the main electrodes of said silicon controlled rectifier so as to open said rectifier, and a switching element connected between said reverse voltage applying circuit and said silicon controlled rectifier. Responsive to the output signal from the reverse voltage applying circuit, the switching element short-circuits the gate electrode and cathode of the rectifier. With this arrangement, it is possible to decrease the capacity of a commutation capacitor constituting part of the reverse voltage applying circuit.

Abstract: A preferential power distribution system for a battery powered camera having an electronic exposure control system, a film transport motor, and an electronic flash unit, in which recharging of the flash unit is controlled by a circuit which responds to the voltage of the battery to inhibit recharging when the battery voltage is low.

Abstract: A photographic flash system in which the storage capacitor for a flash tube is charged only before each flash exposure by a charge control circuit actuated by a pushbutton. The control circuit responds to the discharge of the capacitor through the flash tube to stop the charging process until it is reinitiated by operation of the pushbutton.

Abstract: An electronic flash unit for photographic purposes, in which there is a first thyristor in series with the flash tube, and a second thyristor which, in series with a quenching capacitor, is in parallel with the first thyristor. The first thyristor is quenched at the appropriate time, by quenching current from the quenching capacitor, and after the first thyristor has been rendered non-conductive, the second capacitor is also rendered non-conductive by forced commutation. The arrangement shortens the recovery time of the apparatus, as compared with prior art apparatus of this same general type, to such an extent that the flash apparatus may be used with a motion picture camera as well as a still camera, to produce one or more flashes during each shutter-open cycle of the motion picture camera.

Abstract: A photographic lighting system, particularly for use in photographic studios, including a constant light for illuminating the subject to be photographed while the subject is being placed in proper position and while the photographer is focusing the camera, plus an electronic flash device for illuminating the subject while the actual photograph is being taken. The constant or continuous light is adjustable to vary the degree of illumination produced thereby, and the duration of the electronic flash is automatically adjusted to vary the duration of the flash, in response to the adjustment of the brilliance of the continuous light. The electronic flash tube is powered by a storage capacitor, and charge control means determines the voltage to which the storage capacitor is charged in preparation for an ensuing flash. Blocking means prevents the initiation of a flash unless the storage capacitor is charged to the proper voltage.

Abstract: An electronic flash apparatus includes a correct exposure annunciator which operates if light received from the subject exceeds a predetermined percentage of the required illumination.

Abstract: A correct exposure annunciator for electronic flash apparatus includes an indicator which is turned on when the voltage on a capacitor is less than a predetermined value. The capacitor is discharged in response to a control signal which indicates that proper exposure has occurred. The capacitor is then recharged until the voltage on the capacitor attains the predetermined value and turns off the indicator.

Abstract: In an automatic strobo flash device of the type in which when the quantity of light reflected back from a subject reaches a predetermined level, a switching capacitor is discharged to turn off a silicon-controlled rectifier connected in series to a flash tube so that the strobo flash is automatically extinguished, an indicating means for generating the sound or light signal indicating that the recharge of the switching capacitor is still being made is provided which is actuated when the voltage across a voltage regulator element such as a zener diode inserted in a circuit for recharging the switching capacitor reaches a predetermined level. A malfunction or erratic operation of the strobo flash device may be easily detected, and the correct strobo flash automatically controlled may be ensured.

Abstract: Photographic flash apparatus having one flash unit which may be called the main or master or primary flash unit, and one or more additional flash units which may be called secondary or slave or dependent units. Eliminating connecting cables often used in the prior art, and also eliminating ratio frequency controls sometimes used in the prior art relating to multiple units, the secondary or dependent units of the present invention are independently powered and are triggered to initiate a flash by the light from the flash of the main unit, and triggered to terminate or discontinue the flash in each dependent unit when the flash in the main unit turns off. The control of each secondary unit is entirely by means of the flash of light from the main unit. The apparatus is particularly useful in studio lighting where it is desired to illuminate the subject being photographed from a plurality of different directions.

Abstract: An improved remote light sensor for use with an electronic flash unit is disclosed. The remote light sensor generates a termination signal to terinate the light provided by the flash unit when sufficient light is received from the scene being illuminated.

Abstract: An electronic flash apparatus terminates the light flash when light received from the subject has reached a predetermined level. The light terminating means includes a terminating capacitor which is discharged during the termination of the flash. Annunciator control signal generating means senses when the terminating capacitor is being recharged, and produces an annunciator control signal. An annunciator receives the annunciator control signal and provides an indication that the light terminating means has terminated the flash.

Abstract: Operation of the release contact causes a capacitor in the light measuring circuit to be connected to the D.C. supply. The voltage across the capacitor is applied to the gate of a thyristor in the ignition circuit. Only when the voltage across the capacitor has reached a value for proper operation of the exposure control circuit which terminates the flash, is sufficient voltage applied to the gate of the thyristor in the ignition circuit to cause it to fire, thereby causing the flashtube to ignite.

Abstract: A relaxation circuit effects the drive of a blocking invertor for supplying a discharge lamp, thus enabling this invertor to operate in a wide range of the electric input voltage while the whole arrangement has a high efficiency.

Abstract: An automatic flash device comprising:A power source,A main capacitor to be charged to a certain level by said power source,A discharge circuit being connected to said main capacitor,A control circuit to make the amount of electricity discharged by said discharge circuit correspond to flash photographing information,A means to start discharging, which is actuated after a shutter release means of a camera is actuated to start the discharging of said main capacitor, andA means to cause a flash tube to emit light when the amount of electricity charged at the main capacitor reaches such a value as corresponds to flash photographing information.

Abstract: In electronic flash apparatus having a flash trigger switch and a flash termination switch, an RC network is provided to apply current to the control electrode of the flash termination switch when the flash trigger switch is in a conductive state.

Abstract: In electronic flash apparatus having a flash trigger switch and a flash termination switch, protection against damage from large negative gate voltages is provided. The gate of the flash trigger switch is connected to the cathode of the flash termination switch, and the gate of the flash termination switch is connected to the cathode of the flash trigger switch.

Abstract: False triggering of the flash termination switch in a series termination electronic flash unit as a result of contact bounce is eliminated. Gating means inhibits the contacts from triggering the flash termination switch unless a voltage at a selected point in the circuit has attained a predetermined value. False triggering of the flash ignition as a result of noise present on the synchronization switch line is also inhibited.

Abstract: A photographic camera and multi-flash arrangement therefor in which a multiplicity of linearly arrayed flash lamps mounted in a cartridge, wherein one or more of said lamps may be inoperative, may be automatically and sequentially sampled and the operative ones of said lamps automatically selected for effecting a photograhic exposure.

Abstract: An electronic flash unit for use with cameras having a flash lamp firing mechanism adapted to fire flash lamps in timed relation with the operation of a camera shutter. An electronic time delay circuit coupled to the flash lamp firing mechanism energizes a flash unit trigger circuit to fire the flashtube in synchronism with the camera shutter. A voltage-sensitive switching element renders the delay circuit operative once the flash unit firing capacitor is charged above a predetermined level. With this arrangement, the flash-firing mechanism cannot energize the flashtube trigger circuit when there is insufficient firing capacitor voltage.

Abstract: A circuit for operating a high power ionizable discharge device such as a xenon flash tube or other gas filled lamp includes a trigger circuit for gating the device periodically to produce a discharge condition. A capacitive energy storage circuit discharges through the device when the device is placed in a discharge condition. A low resistance power supply circuit charges the energy storage circuit. First and second sensing circuits respectively detect the charge level of the energy storage circuit and detect discharge of the discharge device. A switching device comprising a zero crossing solid state relay controls the energization of the power supply circuit. A control circuit is operated by the first sensing circuit to operate the switching device so that the power supply circuit is deenergized when the energy storage circuit is charged to a predetermined level.

Abstract: A circuit for the repetitively pulsed operation of a xenon arc discharge lamp. A first SCR is responsive to a first control circuit when fired to allow the charging of a capacitor through a first inductor from a DC energy source. A second SCR is responsive to a second control circuit, and when fired connects the capacitor through a second inductor to a lamp to provide an operating current pulse for the lamp. Also, upon firing of the second SCR, the capacitor supplies a voltage pulse to a pulse transformer which in turn generates a high voltage pulse for ionizing the lamp. The first SCR is responsive to its control circuit to be conductive only when the capacitor is discharged and the second SCR is responsive to its respective control circuit to be conductive only when the capacitor is fully charged. In actual operation, one SCR must have been non-conducting for a predetermined time before the other SCR is allowed to become conductive thereby to prevent shoot-through.

Abstract: A first thyristor gate whose conductive state is determined by the polarity of a signal applied to its control electrode is connected in series with a flash tube for selectively coupling operating voltage from a flash capacitor to the tube. The first gate is opened by a signal of a first polarity derived from the operating voltage source and generated in synchronism with an ignition pulse, which is applied to the trigger electrode of the flash tube to energize the tube. An integrating circuit energized by a transformer coupled to the flash tube output contains a photosensitive element responsive to a portion of the emitted light for developing a control voltage that increases in proportion to the total light integrated. When the output voltage from the integrating circuit reaches a predetermined value, a second thyristor gate whose control electrode is coupled to the output of the integrating circuit is opened to apply a signal of the opposite polarity to the control electrode of the first thyristor gate.

Abstract: An electronic flash system including a flashtube, a trigger circuit for actuating the emission of the flashtube, an electric energy storage means for storing the electric energy emitting the flashtube, a discharge circuit connecting the electric energy storage means to the flashtube to produce a flash of light, said discharge circuit including a switching means for electrically break-and-make controlling a connection of the electric energy storage means and the flashtube, a monitoring means for monitoring luminosity of the reflected light from the object to be photographed relying on the flash of light, said monitoring means being adapted to generate an output signal when the luminosity reaches a predetermined value, and a control means for controlling actuation of the switching means in the discharged circuit, said control means being started by its operation in response to actuation of the trigger circuit, the control means generating a control signal for controlling operation of the switching means to open

Abstract: A wireless multiflashlight apparatus simultaneously illuminates a subject by flashlight rays emitted from a main flashlight device mounted on a photographic camera and at least one additional flashlight device located at suitable position away from the main flashlight device. In the main flashlight device is provided a flash tube arranged to emit substantially two or more flashlight rays at a predetermined time interval therebetween upon the shutter operation of an associated camera. In the additional flashlight device are provided a decoder for producing an outlet signal only upon receipt of the flashlight rays from the main flashlight device through a photo-electric conversion element and an amplifier, and a flash tube operative to be triggered only by the output signal from the decoder. The additional flashlight device is protected from inadvertently flashing even upon reception of any flashlight rays from other flashlight devices than the associated main flashlight device.

Abstract: Circuits and auxiliary elements for use with a device for controlling the emission of light pulses from a flash unit, which light pulses are produced by the discharge of current pulses from a capacitor, the device including a light sensing element for receiving light produced by the flash unit and reflected from an object in the light path. One such circuit includes two zener diodes for providing threshold voltages for use in comparing the output of the light sensing element. Another such circuit compensates for nonlinearities in the response of certain components of the device.

Abstract: A main capacitor is connected across a series combination of a flash discharge lamp and a thyristor to flash the flash discharge lamp through the thyristor in its ON state. A commutation circuit connected to the thyristor includes a commutation capacitor and another thyristor turned on upon a flashing light from the flash discharge lamp reaching a predetermined magnitude. When turned on, the latter thyristor permits the commutation capacitor to supply a reverse voltage to the first thyristor to turn it off. A semiconductor diode is connected between the commutation capacitor and the first thyristor to prevent that capacitor from applying a forward voltage to the first thyristor.

Abstract: An arrangement for controlling the flash duration in photographic cameras. A light-sensitive element within the apparatus responds to light originating from the source for flash bulbs and reflected by the object or scene to be photographed. The flash bulb is ignited by an ignition circuit which also generates the operating voltage for the light-sensitive device. Through the application of a discharge tube which has a considerably lower internal resistance, when ignited, than the flash bulb, the latter becomes extinguished when the .Iadd.quantity of .Iaddend.light reflected by the object or scene and impinging upon the light-sensitive device, is .[.of.]. a predetermined .[.magnitude.]. .Iadd.quantity..Iaddend.