Abstract: The present invention relates to a light-sensing circuit used in a so-called light regulating type flash device to automatically control the amount of flash emitted. In the present invention, a flash photographing with an appropriate exposure is done, securing such flash amount as providing appropriate exposure always regardless of the position of an object in a photographing frame. This is done by making light-sensing for each of different zones independently using a plural number of light-sensing circuits for stopping the flashing by the output of the one light-sensing circuit reaching a prescribed level of output from the different light-sensing circuits.

Abstract: In a photographic flash device comprising a flash discharge tube, for example a xenon discharge tube, a main capacitor which is connected across electrodes of said flash discharge tube and is for storing electric charge to be discharged in said flash tube, a triggering capacitor which is connected in series with a primary coil of a triggering transformer and a synchronous switch, and a voltage indicating glow discharge lamp for indicating completion of charging in the main capacitor.A safety circuit for prohibiting accidental flashing is constituted by comprising a switching means which suspends function of said triggering capacitor.

Abstract: An ignition circuit is provided for extinguishing tubes in electronic flash equipment for photography. The second winding of an ignition transformer is arranged in series to the extinguishing tube. A diode is connected in parallel to the secondary winding of the ignition transformer through which the extinguishing tube current flows after ignition. The extinguishing tube does not require an ignition electrode. The ignition circuit is advantageously employed in electronic flash equipment for photography having an automatic circuitry for control of flash luminance time.

Abstract: A method and apparatus for regulating the output flux generated by a lamp with the degeneration of the voltage from a power source such as a battery. The regulating circuit maintains a constant luminous flux output from a lamp over a substantial range of voltages by switching the voltage to the lamp on and off at a preselected and controlled duty cycle. The duty cycle varies with the variations in the lamp electrical operating parameter provided to the regulating circuit. The regulating circuit permits the useful life of a power source to be substantially increased before requiring replacement.

Abstract: An electronic flash apparatus comprises a discharge circuit and termination circuit for terminating the discharge circuit. The discharge circuit comprises an energy storage capacitor and a series circuit formed of a flash tube and a first switching element connected in parallel to the energy storage capacitor. The first switching element is rendered inoperative by a reverse voltage which is temporarily supplied when energy stored in a commutation capacitor of the termination circuit is discharged by a second switching element. When a prescribed period of time has passed after the first switching element is turned off, the switching element is again put into operation by a retrigger circuit. The commutation capacitor is reversely charged through the flash tube after the first switching element is turned off. The reverse charge is discharged by the retrigger of the first switching element.

Abstract: An auxiliary electronic flash apparatus coactuable with a main electronic flash apparatus of the type having a first flash lamp for converting the energy stored on a first main capacitor into light for illuminating a subject, and a control circuit for turning off the first flash lamp when the light emitted from the first flash lamp and reflected back from the subject reaches a predetermined amount. The auxiliary electronic flash apparatus includes a photometric circuit responsive only to the light emitted from the first flash lamp within a predetermined light wavelength range for generating a flash start signal in response to which a second flash lamp in the auxiliary electronic flash apparatus is turned on and for generating a flash and signal in response to which the second flash lamp is turned off.

Abstract: A blocking converter is provided having a switching transistor controlled via a triggered monoflop with a defined on-time RC circuit which insures that the same electric energy quantity is always stored in a transformer driven by the switching transistor. The electrical energy is reversed to charge the charge capacitor during a blocking phase of the switching transistor. As soon as the reverse charge process is completed, the monoflop is retriggered. The blocking converter is preferably used in battery-operated electronic flash equipment for photography.

Abstract: AC powered flash tube control circuitry includes an energy storage circuit and a firing circuit. The storage and firing circuits are triggered in each flash cycle in separate coordinated sequence in time synchronism with the frequency of the AC source to store energy in a first portion of each flash cycle and to trigger the tube into conduction in a second portion of the flash cycle during which energy from the storage circuit is discharged from the flash tube to produce an output flash of radiation.

Abstract: A glow lamp for indicating charged readiness of a flash apparatus is provided with a predetermined burning voltage corresponding to a specific charge voltage of the storage capacitor for the flash circuit, and the ignition voltage for the glow lamp is applied as periodic ignition pulses derived from voltage pulses occurring on periodic switching of the converter. The result is a more accurate response of the glow lamp to the desired charge value of the storage capacitor than is obtained by using the ignition voltage of the glow lamp as a threshold value.

Abstract: The flash unit includes a flash element and a first electronic switch connected in the current path of the flash element. The flash element is ignited by rendering the first switch conductive. Flash-terminating circuitry terminates the flash by rendering the first switch non-conductive. The flash-terminating circuit includes a commutation capacitor and a second electronic switch interconnected with each other and with the first switch for applying the commutation capacitor voltage to the first electronic switch as a reverse-bias voltage when the second electronic switch is rendered conductive. The second electronic switch is a two-electrode electronic switch which can be rendered conductive by raising the voltage across its electrodes above the value at which such voltage is normally maintained.

Abstract: In an electronic flash device, wherein electrical energy stored by a main capacitor and an electronic flash tube is fired by the stored energy, a relaxation oscillator is adapted to oscillate when the main capacitor is charged to a given voltage level, which is a condition for completion of preparation for flash tube operation. The relaxation oscillator includes a capacitor, a glow discharge tube, and a resistor and the oscillation thereof causes intermittent glow discharge through the glow discharge tube for indicating the completion of preparation for flash tube operation. The electronic flash tube is triggered to emit a light flash by the stored energy of the relaxation oscillator capacitor. Excitation of the flash device, even with a power supply switch open, is prevented by isolating the main capacitor from the trigger capacitor and also from the glow discharge tube to also prevent an indication of flash preparation.

Abstract: A battery operated, capacitor discharge type electronic, photoflash system having an electro-mechanical switching means for automatically disconnecting the battery to minimize unnecessary discharge of the battery. The system causes the battery to be disconnected at a predetermined time interval after a charge cycle has been started for a discharged main capacitor or after the main capacitor has been fully charged for a predetermined period of time.

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 a switch which is selectively operable to permit control of termination of the emission of light pulses at either one of two light intensity output levels. Another circuit permits one light sensing element to normally trigger the emission of a light pulse in response to a light pulse from a remote unit, and to be selectively connected to subsequently control termination of such emission. One such element is a special gas filled switching tube having two internal electrodes for triggering conduction through the tube in response to a low voltage.

Abstract: A pulse generating circuit is provided by charging from a DC power source through charging resistor to a capacitor; detecting the preset value of the charging condition of the capacitor; discharging the charge of the capacitor through a main thyristor by triggering the main thyristor and generating a pulse output to a load by the discharging current. The pulse generating circuit comprises a shunt circuit for dividing the voltage of the DC power source beside the circuit for charging the capacitor whereby the potential of the shunt point is compared with the charged voltage of the capacitor through a three terminal trigger element and the trigger element is turned on when the charged voltage of the capacitor becomes substantially equal to the voltage of the DC power source to obtain the trigger output of the main thyristor.

Abstract: An automatic flash-limiting arrangement for use in combination with a flash unit associated with a camera and arranged to automatically terminate the light flash produced by the unit when the subject has been properly exposed, the flash-limiting arrangement being associated with the flash unit so as to become operative only upon initiation of a light flash, thus assuring that the arrangement will not respond to extraneous flashes occurring before the flash which is to be controlled. The flash-limiting arrangement is constructed to sense the light being received by the camera, to produce a signal which is the sum of a component proportional to the time integral of the intensity of such light and a component which is proportional to the instantaneous amplitude of the intensity of such light, and to terminate the flash when this signal reaches a predetermined value.

Abstract: An electronic flash apparatus is provided with a display element positioned in the view-finder of a photographic camera so that the operator is immediately aware if the flash tube has been fired in response to the closure of the synchronous switch. The light emitting operation of this display element is controlled by use of a signal generator arranged to be responsive to the occurrence of discharge through the flash tube of the flash apparatus. With this apparatus, therefore, the operator may rely upon the appearance of this display element to insure that the firing is effected by the flash apparatus even when the object-to-camera distance is relatively small.

Abstract: A neon tube flashing device having a neon tube which emits light upon application of a predetermined voltage thereto to effect indication of operational conditions comprises a capacitor parallel-connected to the neon tube, and switch means series-connected to the capacitor and parallel-connected to the neon tube. The neon tube may be caused to effect flashing by charging-discharging of the capacitor during conduction of the switch means.

Abstract: A stroboscope for a camera wherein the energy stored on a main capacitor is converted by a flash lamp into a flash of light. It is provided with a flash delay means for maintaining constant a time delay elapsing from the time the stroboscope receives a flash command signal from the camera to the time the flash lamp flashes irrespective of the magnitude of the voltage charged across the main capacitor, whereby a stroboscopic circuitry may be considerably simplified.

Abstract: An adapter for electronic flash apparatus comprises a pair of first external connection terminals detachably connected to high tension pulse takeout terminals of a camera incorporating means for generating the high tension pulse in response to the action of the shutter of the camera; and a pair of second external connection terminals detachably connected to a pair of terminals of a trigger circuit included in an electronic flash apparatus or unit which further comprises a power supply and a flash discharge lamp supplied with the power supply voltage and in which the trigger circuit is supplied with the supply voltage between the trigger circuit terminals to start the flash discharge lamp when the pair of terminals of the trigger circuit is short circuited.

Abstract: The trigger circuit of an electronic flash device includes a pulse transformer connected to a trigger electrode of a flash tube, a capacitor connected to the pulse transformer, a thyristor connected in the discharge path of the capacitor, and a control circuit for the thyristor. This control circuit is provided with a low-voltage trigger means for applying a trigger pulse to said thyristor and further with a synchronous switch connected therein so that the synchronous switch operates with a low voltage.

Abstract: Electronic photoflash unit has functions as a remote control device transmitter and as photoflash for flash photography. The photoflash unit decreases the amount of radiated light when used as the remote control device transmitter and increases the light when used as the photoflash for making photographs.

Abstract: An electronic flash unit for photographic purposes, with improved means for quenching the flash when sufficient light has been emitted from the flash tube. The discharge circuit of the main storage capacitor comprises the flash tube and a switch thyristor in series with each other. A quench circuit including a quenching capacitor and a quenching thyristor will deliver a quenching current to the switch thyristor when the quenching thyristor is triggered by exposure metering and flash limiting mechanism, this mechanism including a resistor, a phototransistor, and an integrating capacitor in series with each other and in parallel with a feed capacitor which supplies feed current to the exposure metering and flash limiting mechanism, and which is in parallel with the switch thyristor.

Abstract: An improved trigger circuit for triggering an electronic flash apparatus and for energizing a remote sensor is disclosed.

Abstract: This invention relates to an improved small-sized electric flash device wherein transformers of its DC-DC converter circuit for producing a high voltage comprises printed coil or coils thereby efficiently reducing their volume and sufficiently flattering their shape, so that, together with miniaturized circuit parts and printed circuit substrate, highly integrated, hence compact photographic flash device is obtainable.

Abstract: An automatic electronic flash device including: a flash discharge tube, a first switching element connected in series with the flash discharge tube, a main discharge capacitor adapted to supply its charged energy to the flash discharge tube for firing thereof so that an object to be photographed is illuminated, a light receiving circuit which receives light reflected from the object for turning on a second switching element when the amount of the received light reaches a predetermined value, a commutation capacitor which is made to discharge in response to the second switching element being turned on and supplies a reverse current through the first switching element whereby the first switching element is turned off so as automatically to stop illuminating, a trigger circuit for supplying a high voltage pulse to the trigger electrode of the flash discharge tube, and a high voltage supply circuit which generates a high voltage in synchronism with the operation of the trigger circuit so that the generated voltag

Abstract: Electronic flash apparatus includes a flash storage capacitor, a flash tube for selectively discharging the flash storage capacitor to produce light flashes, and terminating means for terminating the light flash. Separate charging means supplies charging current to the flash storage capacitor. Control means causes the charging means to supply the charging current to the flash storage capacitor each time the terminating means terminates a light flash.

Abstract: An electronic flash unit for igniting a gas discharge flash lamp by means of a piezoelectric element. The unit input terminals are interconnected by a series circuit comprising a rectifier and an undercritically damped parallel LC circuit. The lamp starting electrode is coupled to one main electrode via the inductor (L) and exclusive of the rectifier. The unit produces a lamp ignition signal consisting of a pulse train of alternating polarity which provides more reliable ignition of the flash lamp.

Abstract: A chopper circuit arrangement for charging an electronic flash discharge capacitor and for turning off the chopper is disclosed. The arrangement operates from a D.C. source and includes chopper transistors and a transformer operating together as a converter. Regenerative means, including a feedback winding of the transformer, function to charge the flash discharge capacitor. The arrangement includes transistors disposed across the chopper transistors to block or hold the converter off. These blocking transistors are activated when the voltage across the discharge capacitor has achieved a predetermined value. The arrangement includes means for effectuating blocking of the converter only during the off condition of the chopper. The arrangement also includes means for delaying the charge of the discharge capacitor, after discharge, for a predetermined time.

Abstract: An automatic photographic flash device wherein the amount of light of the flash tube is automatically controlled in response to intensity of light from the direction of the photographic object by means of an electric circuit A flash tube part is movably installed on a main case part containing a battery and the circuit A switch is installed in the device in such a manner that when the flash tube part is moved to a position not directed at the photographic object, the switch causes the circuit to appropriately increase the amount of light discharged by the flash tube when it is actuated.

Abstract: A system for charging an energy storage capacitor for use with an electronic flash lamp or laser employs stepped sequential application of increasing charging voltages to the capacitor. In an inverter-type power supply, a transformer has a tapped primary and a single secondary, output of which is rectified and applied to the capacitor. A plurality of pairs of drive transistors are used to apply an alternating voltage to progressively decreasing portions of the transformer primary, in response to a feedback signal indicative of the voltage to which the capacitor has been charged. This feedback signal is utilized by a level detector and associated drive control logic to enable a different pair of drive transistors each time a preestablish charge voltage level has been reached. A driver inhibit circuit insures that, as each pair of drive transistors is alternating on and off, that one transistor is fully off before the other is turned on.

Abstract: There is disclosed herein a voltage regulator for a power supply for load devices such as electronic photoflash units. The voltage regulator supplies power to charge the main capacitor of the photoflash unit to an appropriate voltage, and uses a semiconductor series regulator circuit. The voltage regulator provides medium-to-long term heat integration to terminate power supplied to the electronic flash unit in the event of a thermal overload in order to protect the electronic flash unit. The circuit includes a ready indicator to indicate when the main capacitor of the flash unit has reached the appropriate charge, and also includes an overload indicator to indicate an overload condition.

Abstract: The invention relates to an electronic flash device which is provided with a series arrangement of an electronic flash tube and a thyristor, which flash device is equipped with a flash duration limiter (computer electronic flash device).According to the invention a rectifier is connected anti-parallel to the thyristor. As a result a smaller thyristor can be used, while the energy consumption can be reduced and an unwanted "light spike" at the end of the flash duration can be avoided.

Abstract: A step-up DC converter suitable for construction as an integrated circuit chip provides a separate rectangular wave oscillator using a silicon transistor and a power amplifier driven thereby which supplies current to the primary winding of a two-winding step-up transformer matched to the constant duty cycle of the oscillator thereby simplifying construction of the transformer and permitting the oscillator and power amplifier voltage step-up transformer functions to be individually optimized for overall high efficiency operation. A hysteresis switching voltage comparator senses the rectified value of the high voltage output from the transformer relative to a stable reference voltage and switches both the oscillator and the amplifier to their standby current condition when a predetermined high output voltage level is obtained and switches both oscillator and amplifier into conduction when the output voltage falls to a predetermined level.

Abstract: A relatively infinitely incremental mode of obtaining any desired brightness of flash from an electrically operable flash-tube is attained by employing plural capacitors, each having a charging source of selectable voltage level and a unilaterally conductive element between the capacitor and the flash-tube. The unilaterally conductive element is poled to pass the charge on the associated capacitor during the discharge cycle regardless of the voltage of the charge on other of the plural capacitors involved.

Abstract: Voltage indication means for an electronic flashing device in which a low D.C. voltage is converted to a high D.C. voltage by a DC-DC converter circuit and energy stored in a main discharging capacitor is supplied to a flashing discharge tube to fire it, wherein the charged voltage of the main discharge capacitor is indicated by utilizing the fact that the charged voltage of the main capacitor is in equivalent relation with a voltage generated in the DC-DC converter.

Abstract: A simplified voltage regulating circuit is provided for controlling the operation of a d-c to d-c converter oscillator as is commonly used in an electronic flash. The voltage regulating circuit controls the operation of the d-c to d-c converter so that the output voltage from the oscillator is maintained within a prescribed range. The voltage regulating control circuitry includes an ordinary transistor controlled by way of an output voltage sensing zener diode which operates to turn on the transistor and thereby terminate operation of the oscillator when the output voltage therefrom reaches its maximum value within the prescribed range. A capacitor is also charged by way of the transistor when it turns on and the residual charge of the capacitor thereafter operates regardless of the non-conductive state thereafter assumed by the zener diode and transistor to maintain the oscillator off until the output voltage from the oscillator decays to its minimum value within the prescribed range.

Abstract: A photographic camera is provided with means for detachably mounting either a flashbulb flash unit or an electronic flash unit. The camera includes a piezoelectric transducer mechanically activatable for generating voltage impulses. When the flashbulb flash unit is mounted on the camera, the voltage impulses are directly applied across the terminals of the flashbulb. There elapses a certain time interval between the start of flashbulb firing and the development of maximum flashbulb output illumination. This time interval is taken into account in the design of the shutter-activating mechanism. When, instead of the flashbulb flash unit, the electronic flash unit is mounted on the camera, the voltage impulses generated for flashbulb firing are utilized to initiate operation of the electronic flash unit. Because the flash tube of the unit develops maximum output illumination more quickly than does a flashbulb, a time-delay circuit is utilized to effect compensation.

Abstract: A quench strobe is provided with a resistor for effecting the quenching thereof at a predetermined rate which controls the amount of exposure influencing artificial illumination emitted subsequent to the quench trigger signal so that such exposure influencing artificial illumination closely correlates to the amount of exposure influencing illumination normally expected subsequent to the command signal to close the camera shutter blade elements and automatically anticipated by the camera exposure control system.

Abstract: An electronic flash unit having the conventional flash tube, storage capacitor dischargeable through the flash tube, measuring device for recording the quantity of light emitted by the flash tube and reflected back from the subject being photographed, a pulse generator responsive to the measured reflected light, and means for quenching the flash in response to a pulse produced when the measured reflected light reaches a threshold value. The present flash unit, in addition to the conventional features just mentioned, includes the novel feature of a light-emitting diode which becomes illuminated when the light measuring means and the pulse generator circuit become operative, thus signalling to the user of the device that the so-called "computer" mechanism has actually operated. Circuit means is provided for extinguishing the light-emitting diode at the proper time.

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 a switch which is selectively operable to permit control of termination of the emission of light pulses at either one of two light intensity output levels. Another circuit permits one light sensing element to normally trigger the emission of a light pulse in response to a light pulse from a remote unit, and to be selectively connected to subsequently control termination of such emission. One such element is a special gas filled switching tube having two internal electrodes for triggering conduction through the tube in response to a low voltage.

Abstract: In an electronic flash unit serving both as the transmitter of a remote control device and a flash unit for flash photography, there is provided a power source, a flash discharge tube, and a discharging circuit having an interlocking switch adapted to be closed in response to electrical connection of the flash unit to the synchro contacts of a camera. The discharging circuit may produce a greater magnitude of discharging current for the flashing of the discharge tube during the closing of the switch than during the opening of the switch. The flash unit further includes a trigger circuit having an extraneously operable trigger switch and effective to trigger the flash discharge tube to effect the discharge of the discharging circuit. Thus, the quantity of flash light emitted from the flash discharge tube is less during the disconnection of the flash unit to the camera's synchro contacts than during the connection of the flash unit to said synchro contacts.

Abstract: An electronic photographic flash apparatus which is useful as an artificial light source for taking photographs. The apparatus of this invention does not use an AC charger or the like as its power source, but it uses a plurality of secondary batteries normally held in a charged state by a primary battery, whereby when the flash apparatus is to be used, the connection of the plurality of the secondary batteries is changed to quickly charge a main discharge capacitor of the flash apparatus. By virtue of the ability of the apparatus to quickly charge its main discharge capacitor, the electronic flash apparatus in accordance with the present invention can effectively associate its operation with the operation of the shutter release of a photographic camera when it is incorporated in the latter.

Abstract: A circuit arrangement for igniting flash tubes, without using an ignition electrode, and having two main electrodes which are supplied with an ignition pulse parallel to a flash capacitor and an electronic switch, employs an electronic switch which also constitutes a gas discharge path. In particular the electronic switch may be realized as a flash tube.

Abstract: A circuit arrangement for charging a flash capacitor of a designated rated voltage from a DC source of a higher rated voltage. A thyristor in the line from the DC source is blocked when the voltage for which the flash capacitor is designed is reached.

Abstract: An electronic flash unit for use with a flash-trigger mechanism having a piezoelectric generator. An RF coil or inductor interconnects the piezo crystal and flash-trigger electrode and operates to modify the energy distribution of the piezo output pulse so as to more reliably fire the flashtube for a given amount of charge on the flash unit firing capacitor.

Abstract: An electronic flash device includes a control circuit for extending the operational life of the flash battery. In one preferred embodiment the flash device is of the type having a monitor circuit responsive to the charge on the flashtube firing capacitor that (1) operably couples the flash battery to a charging circuit when the charge on the firing capacitor is below a predetermined level, and (2) de-couples the battery from the charging circuit when the firing capacitor charge is above the predetermined level. The control circuit comprises a counter for counting the number of times the monitor circuit couples the battery to the charging circuit and for producing a control signal, when the number counted reaches a pre-set value, that overrides the monitor circuit to maintain the battery de-coupled from the charging circuit.

Abstract: The device according to this invention has a flash tube of the electronic type which is triggered when a charge stored in a capacitor is applied to the tube. A circuit is provided which measures light that is emitted from the tube and is reflected from an object. The light value of the reflected light is compared against a reference value and the emission of light from the flash tube is terminated when the reflected light reaches the level of the reference value. The reference value is electrically set by a mechanism calculating an aperture value set in the camera with a sensitivity value of a film to be used in the camera.

Abstract: In an automatic control apparatus for controlling the quantity of light from a flash device, a first photocell device, responsive to the light from the flash device, is serially connected with a second photocell device, responsive to light reflected from the photographic object, and the output from the second photocell device is integrated and used for energizing known apparatus for preventing the light generated by the flash device from reaching the photographic object to optimize the light illuminating the photographic object. The second photocell device has a lower output than the first photocell device, thereby enabling the output from the second photocell device to determine the light measurement. The first photocell functions as a gate in response to the direct light emission from the flash device to prevent spurious and undesirable actuation of the second photocell device.The first and second photocell devices may each be phototransistors or photodiodes.

Abstract: Electronic flash apparatus of the general type having exposure-measuring and flash-limiting mechanism comprising a light-sensitive element connected in series with an integrating capacitor and a thyristor, arranged so that when the thyristor becomes conductive, it causes a pulse which interrupts or terminates the flash. In distinction from prior flash apparatus of this same general type, the present apparatus has circuitry in which one plate of the integrating capacitor is connected to the collector of a photo-transistor and the other plate is connected to the control grid of the thyristor and to a higher voltage source, while the emitter of the photo-transistor is connected to a lower voltage source.

Abstract: The visibility of warning lights employing flash tubes is enhanced by control circuitry which generates closely spaced trigger pulse pairs for energizing the tubes to thereby produce double flashes. Noticeability of the warning light may be enhanced by addition thereto of a noise maker which operates off the same power supply that provides a high voltage for operating the flash tube or tubes.