Abstract: An electronic flash apparatus comprises a flash lamp and a semiconductor switching element which are connected in series across a main capacitor, and a flash control circuit which measures light reflected from an object to be photographed illuminated by flash light produced by the flash lamp, and produces a control signal to render the semiconductor switching element nonconductive. The flash control circuit includes a photoelectric converting circuit for converting the reflected light into a voltage signal, an integrator for integrating the voltage signal, and a comparator for comparing the output voltage from the integrator with a reference voltage. To obtain a proper flash exposure a compensation signal generating circuit is provided which is responsive to the initiation of flashing of the flash lamp to produce a compensation signal having a desired waveshape. The compensation signal acts on the flash control circuit to control the generation timing of the control signal.

Abstract: A computer type electronic photoflash consisting of a main photoflash unit having photoflash emission and photoflash light volume control functions and a plurality of adapters connectable thereto. Each of said adapters is used with a photographic camera for which an electronic photoflash of special make and design is to be used exclusively. Each adapter serves for relaying electrical signals between the camera and the main photoflash unit and has an electric circuit adapted for this purpose. Thus, the number of the adapters is selected to be equal to the number of different descriptions of the photographic cameras for which respective electronic photoflashes of special make and design are to be used exclusively.

Abstract: This invention discloses an electric flash device which comprises a direct current power source circuit, a flash tube circuit including a flash tube, a voltage convertor including an oscillator circuit, an oscillating transformer and an oscillation starting circuit, a rectifier circuit for rectifying an altanating current voltage from the voltage convertor and a charging circuit including a main storage capacitor for storing an electric energy to be supplied to the flash tube, a triggering circuit for firing the flash tube, said oscillator circuit includes an oscillating switching element which has a high leak resistance, and said oscillation starting circuit includes a switch element for starting the actuation of said voltage convertor.

Abstract: An electronic flash apparatus provided with a main flash apparatus having a first flash discharge tube and a sub-flash apparatus having a second flash discharge tube. The sub-flash apparatus is attached to the top of the main flash apparatus so that it may be rotated in horizontal and vertical directions.

Abstract: A photographic exposure and flash fire control system initially measures ambient scene light and subsequently utilizes the results of that measurement to control the amount of artificial illumination provided during the exposure interval. The initial measurement of ambient scene light below a first select level provides for a maximum flash output while conversely the initial measurement of ambient scene light above a second select level greater than the first select level provides for minimum flash output. The initial measurement of ambient scene light between the aforementioned first and second levels provides for a flash output which progressively varies between the aforementioned minimum and maximum outputs in inverse corresponding relation with respect to the progressive variation of measured ambient scene light between its first and second select levels.

Abstract: A circuit for flash equipment having a trigger control switch or an SCR with its gate lead connected to a condenser through a switching transistor which is rendered conducting when the main flash capacitor is charged to the normal firing voltage and when the X sync contact is closed. After a time interval from the closure of the X sync contact, the condenser is short-circuited to prevent refiring of the flash tube. Such refiring would otherwise be caused when the condenser is recharged to actuate the SCR during the period of closure of the X sync contact.

Abstract: An electronic flash unit has a flash tube and a flash circuit which includes an internal light sensor that interrupts the supply of electricity to the flash tube when it senses that the flash light reflected from an object exceeds a predetermined threshold value. The unit also has a connector for connecting it to an external light sensor and an arrangement for disconnecting the internal sensor from the circuit when connection is made to an external sensor, and vice versa. An adapter circuit is connected to the connector and allows the unit to be used with a camera having its own built-in light sensor so that, when the unit is used with such a camera, the camera sensor performs the function otherwise performed by the internal sensor of the unit.

Abstract: In an electronic photographic flash apparatus comprising a DC-DC converter, a high tension capacitor, and a gas-discharge flash tube to produce a light flash by consuming electric energy stored in said high tension capacitor,the improvement is that the apparatus further comprisinga low tension capacitor and a switching circuit which connects the low tension capacitor parallel to the DC low voltage source for charging therein at an off-state of the apparatus, and connects the low tension capacitor in series to the DC low voltage source in a subsequent stand-by period thereby to boost the operation of the DC-DC converter at an initial stage in the waiting time when the power switch is on, so as to quickly charge up the high tension capacitor.

Abstract: In a DC-DC converter for an electronic flash unit disclosed, an npn transistor is used as an oscillating transistor. The emitter of the npn transistor is connected to a main capacitor of the flash unit at least through a secondary winding of the converter. A diode is connected between the secondary winding and the main capacitor in such a manner that the emitter current of the npn transistor can flow into the main capacitor as an charging current through the secondary winding.

Abstract: A process and apparatus for charging a capacitor, particularly for flash guns with a fast flash series, so as to achieve a short charging time while avoiding a high charging current pulse, the charging current during the course of the charging being regulated to a value which at least approaches a constant. The time constant of the charging circuit is altered during the charging process by a controlled resistance arrangement which is controlled in dependence upon the charging voltage of the capacitor.

Abstract: An electric flash discharge device comprises a capacitor charged by a power source, a trigger device including an operating member for producing a trigger signal in response to the actuation of the operating member, and a discharge tube connected to the capacitor and trigger device so as to be triggered in response to the trigger signal to form a discharge circuit for the capacitor. A control signal generator is provided for providing a control signal in response to generation of the trigger signal, and a current control means is connected between the capacitor and the discharge tube for controlling, in response to the control signal, the discharge current flowing through the discharge tube so that the discharge current gradually increases from a low value to a peak value after initiation of the discharge as a function of the control signal.

Abstract: In an automatic flash duration controllable electronic flash system of the type in which in response to the quantity of light reflected back from a subject illuminated by the flash light emitted from a flash lamp and intercepted by a photosensor circuit or the like, the flash lamp is turned off, a signaling device capable of signaling not only whether or not the voltage stored across a main discharge capacitor has reached to a predetermined level for flash exposure but also whether or not an automatic flash duration control after triggering the flash lamp has been completed.

Abstract: A series control type automatic flash unit which is capable of achieving completely controlled flashing by controlling electrical energy supplied from a main capacitor to a discharge lamp by means of a first switching element connected in series with the discharge lamp. A series circuit of a second switching element conducted by a light control signal derived from light control means and a commutation capacitor is connected in parallel with the series circuit of the discharge lamp and the first switching element, and the commutation capacitor is charged by charging means in a predetermined polarity. This charging is performed at least prior to the state of commutation, and upon conduction of the second switching element by the light control signal, stored charges of the commutation capacitor are applied via the second switching element to the first switching element to place it in a reverse biased condition. As a consequence, the first switching element is turned OFF to stop lighting of the discharge lamp.

Abstract: An automatic electronic flash device for use with a camera includes a flash tube carried by a housing. A battery is carried by the housing as a source of electric supply. A capacitor is connected to the flash tube to fire it when discharged. A circuit is used to automatically adjust the amount of light emitted from said flash tube upon the firing of the tube. The circuit includes a light receiving element arranged to receive light reflected from a photographic object upon the firing of the tube. The information of distance from the camera to an object to be photographed is fed to the circuit as a function of the amount of light received. A switch is connected to the circuit to cause it to vary the amount of light emitted from the flash tube. A calculator enables calculation of a plurality of combinations of aperture settings and distance setting in response to a film speed setting, so that selection of a desired film speed will result in indication of a desired aperture setting and distance setting.

Abstract: A strobe apparatus for reducing contrast index in photographic copies by employing an illumination pulse of short duration includes a source energizable at both a relatively high level to provide high intensity illumination and at a low level to provide low intensity illumination.

Abstract: A control circuit for an electronic flash device is disclosed. The control circuit is connected to a commutating capacitor and includes a coil connected in parallel to the capacitor and switching means connected in the discharge path of the commutating capacitor to discharge the charge stored on the commutating capacitor after a switching device for stopping flash emission has changed from the conducting state to the non-conducting state.

Abstract: The emitted light intensity of an electronic flash tube is maintained constant over a given time period by connecting the electronic flash tube in series with an inductor and a switching element across the main capacitor for energizing the flash tube, with a diode being connected across the serially connected flash tube and inductor and a polarity opposite to the current flow from the main capacitor to the flash tube. The switching element is intermittently turned off and on in accordance with the intensity of the light emitted from the flash tube. While the switching element is being turned off, the flash tube is energized by the energy stored in the inductor in the form of a magnetic field. An auxiliary capacitor may be provided across the flash tube. The flash light intensity may be monitored by the measurement of the emitted light, or by the detection of the voltage across the flash tube, or by the detection of the current flowing into the flash tube.

Abstract: An indicator circuit for an auto-strobo unit comprises a switching element which rapidly discharges a capacitor which, when adequately charged, feeds a display element indicating proper operation of the auto-strobo unit. The switching element is turned on in synchronized relationship with the initiation of a flashlight illumination from a flash discharge tube to discharge any remaining charge on the capacitor, thus providing a reliable indication of each flashlight illumination of the flash discharge tube.

Abstract: A battery-powered DC to DC converter is operated dynamically in accordance with the condition of the battery so that an optimum compromise is made between the performance of the battery and the performance of the converter in an application such as charging an electronic strobe flash unit capacitor. A transformer has oppositely wound primary and secondary windings. A switching transistor, serially connected between the primary winding and the battery, interrupts battery current through the primary winding, which causes current to flow through the secondary winding to charge the flash unit capacitor. A voltage-sensing circuit senses the battery open-circuit voltage and the battery load voltage, which varies as a function of the open-circuit voltage and battery internal resistance.

Abstract: An improved electronic flash is provided having a selectively energizable source of illumination, control circuits for controlling the source of illumination according to a plurality of operational modes which include an automatic control mode and a manual control mode and a housing enclosing the source of illumination and the control circuits. According to a preferred embodiment of the instant invention, a frame is mounted upon an outer surface of the housing and an indicator panel may be removably mounted within the frame. The indicator panel is provided with front and rear surfaces and may be selectively mounted within the frame to externally expose either the front or rear surface thereof. One of the front or rear surfaces is provided with indicia for calculating a diaphragm value.

Abstract: In a flash light discharge device including a strobo tube attached to a camera body, both the positive and negative outputs of a blocking oscillator are made use of. One output is used for charging a main capacitor for making the strobo tube discharged, and the other output is used for energizing an indicator or indicators. Both the outputs may be used for charging the main capacitor to accelerate the charging of the capacitor. The indicator energized by the output of the blocking oscillator while the main capacitor is charged may be an indicator which indicates by intermittent lighting that the main capacitor is being charged.

Abstract: In the flash device disclosed, a control circuit for controlling the charging operation of a main capacitor is provided with a switching means for forming a path for charging the main capacitor; and a signal forming circuit which produces opening and closing signals for control over the switching means. The switching means is alternately opened and closed by the opening and closing signals to intermittently charge the main capacitor. When the main capacitor is completely charged, the signal forming means produces only the closing signal causing the switching means to cyclically block the charging path. Thus, even if the switching means is subject to operation by a noise which further charges the main capacitor after the charging operation has been completed, this further charging can be immediately stopped. Thus, the main capacitor does not become overcharged.

Abstract: A photographic flash device comprising a main capacitor for flashing a flash discharge tube, a DC-DC converter, a constant-voltage circuit for controlling the oscillation function of the DC-DC converter and an indication means capable of discriminatively indicating states of the voltage of the main capacitor in three different voltage ranges, first range being from zero to a first predetermined voltage above which flashing is possible, second range being from a first predetermined voltage to a second predetermined voltage, the third range being from the second predetermined voltage to a third predetermined maximum voltage, respectively.

Abstract: A control circuit for flash tube apparatus has a flash tube, a thyristor for controlling the flash tube in ON-OFF fashion, a trigger circuit for triggering the flash tube and thyristor, a commutation capacitor for turning the thyristor OFF, a switch circuit for supplying a charge stored in the commutation capacitor to the cathode-to-anode path of the thyristor. The control circuit further includes a trigger blocking circuit connected between the trigger circuit and the gate of the thyristor, a carrier recombination capacitor connected in parallel with and across the gate and cathode of the thyristor, and a timer circuit for operating the trigger blocking circuit for a predetermined time period. The thyristor is turned ON by a trigger pulse TP2 from the trigger circuit. When the switch circuit is rendered ON, the timer circuit is operated. The trigger blocking circuit blocks the trigger pulse until the discharge of the commutation capacitor is completed.

Abstract: A voltage indicator for a stroboscope, having a high voltage generator (10), discharge capacitor (12), flash tube (20) and trigger circuit (22), which further comprises a light-emission diode (LED) (16) connected in series to a current path for charging the discharge capacitor (12) with electric energy; switch means (14) for selectively operating the LED (16) and a comparator (18) for selectively actuating the switch means (14). The LED (16) is not lighted when electric energy is not sufficiently stored in the discharge capacitor (12) to cause the flash tube (20) to give off flashes. When the comparator (18) detects a sufficient charge of electric energy in the discharge capacitor (12) for the light emission of the flash tube (20), then the LED (16) can be lighted.

Abstract: An operation indicator for auto-strobo unit which includes a single light emitting element capable of indicating the completion of a charging operation or a flashlight illumination of the auto-strobo unit, comprises a bypass circuit which any current flow associated with the indication of the completion of a charging operation is bypassed whenever a current flow associated with the indication of the completion of a flashlight illumination is produced, thus allowing the indication of the completion of a flashlight illumination to predominate over the indication of the completion of a charging operation.

Abstract: A computer type electronic flash device is disclosed. The flash device has an auxiliary capacitor for producing a bias voltage which is to be superimposed on the charged voltage across the main capacitor upon triggering of the flash tube, and an impedance circuit provided in the discharge path of the auxiliary capacitor to produce an actuating voltage for the light measuring circuit when the auxiliary capacitor produces the above-described bias voltage.

Abstract: An electronic flash device capable of emitting a flash light of a regulated level over a considerable duration of time, prior to flash firing for emitting a torrent of flash light for flash photography. The device is provided with two capacitors, one of which is discharged through the flash tube and a current regulation circuit upon actuation of a first trigger switch, and the other of which, for example in relation to shutter release operation, is discharged through the flash tube without regulation of the discharge current upon subsequent actuation of a second trigger switch in relation to shutter opening. The pre-emission of flash light may be used for automatic focusing, automatic diaphragm determination and automatic flash control.

Abstract: A power supply for providing energy to a flash lamp comprising a plurality of capacitors connected in parallel with their outputs connected to the flash lamp. The capacitors are sequentially discharged by circuitry which continually compares the accumulated exposure with a reference signal which represents the desired exposure level. When the desired exposure is sensed, an inhibit signal is sent to the power supply preventing additional capacitors from being discharged.

Abstract: An electronic photoflash device includes a high voltage DC generator, a main storage capacitor and a reflector backed photoflash tube unit mounted on an insulating substrate on which are printed a high voltage conductor line connecting first terminals of the generator, capacitor and tube and a ground conductor line connecting their opposite terminals. The ground line surrounds and is proximate the high-voltage line so that the deposition of water on the substrate extends between and short-circuits the lines to discharge the high-voltage and eliminates the risk of an electric shock to the device operator. Alternative arrangements may be provided for surrounding the high-voltage conductor with the ground conductor, the conductors having proximate bare portions bridged by a surface which, when moistened, short circuits the conductors.

Abstract: A power supply circuit for strobo unit includes a DC-DC converter which steps up a low voltage from a d.c. source to a higher voltage. The converter comprises an oscillation transformer, a PNP transistor and an NPN transistor, both of which are used to form an oscillation circuit. The circuit arrangement provides a stabilized oscillation and eliminates the likelihood of producing an electric shock.

Abstract: A first circuit arrangement including a zener diode coupled to the base of a transistor for keeping the transistor turned ON in response to the magnitude of voltage developed across a storage capacitor. The capacitor provides power to a photographic flash tube connected in series with a silicon controlled rectifier (SCR). After the flash tube is ignited, energy is drained from the charged capacitor until its voltage level reaches a predetermined magnitude at which time the zener diode becomes non-conducting, turning OFF the transistor, which causes a commutation of the SCR, terminating the flash of the flash tube. The capacitor is then recharged for preparation of the next flash operation.A second circuit arrangement utilizes a programmable unijunction transistor in which the voltage magnitude of the flash storage capacitor is followed by the gate of the unijunction transistor until the gate voltage reaches a corresponding voltage level preset at the anode of the unijunction transistor.

Abstract: Circuitry for digitizing received light into a digital pulsating signal, including a photodiode operable in response to light intensity for passing current to a capacitor for developing a voltage level thereacross. A voltage comparator with a hysteresis responds to the magnitude of the capacitor voltage level for tripping the comparator's output between a HIGH and LOW state which directs capacitor discharge to cycle the comparator output in a pulsating manner.In a preferred embodiment, the circuitry is powered by a flash storage capacitor along a pair of conductors which serve both to power the circuitry and to receive pulsating current levels indicating voltage comparator switching. The current levels are sensed and counted for producing a binary count output of received light energy. In another embodiment, the conductors also serve to carry a trigger signal for directing flash initiation.

Abstract: Electronic strobe flash apparatus has first and second flashtubes which are fired alternately and repeatedly to produce a composite, extended light flash. A start pulse triggers the first flashtube to cause a first normally charged capacitor to discharge through a primary winding of a transformer, the first flashtube, and a second normally discharged capacitor, thereby firing the first flashtube and charging the second capacitor. The transformer is adapted to produce a flashtube trigger voltage across its secondary winding when current in its primary winding is interrupted. The second capacitor is smaller than the first capacitor so that the voltage across the second capacitor increases more rapidly than the decrease in voltage across the first capacitor during its discharge.

Abstract: This invention discloses a electric flash apparatus comprising a flash housing which consists of a first casing and a second casing, each of which is pivotably connected, a first flashing member having at least one flash tube and arranged in said first casing, a second flashing member including at least one flash tube and arranged in the second casing, and a flash control circuit arrangement for controlling effectively quantity and a flash duration of flash light of said flash tubes.

Abstract: A quench strobe includes a light integrator circuit with an anticipation network which enables the quench to be anticipated by a predetermined time corresponding to the reaction time of the strobe quenching circuitry so as to avoid overexposure under conditions where the photographic subjects are close to the camera or under conditions of relatively high scene light reflectance.

Abstract: In an automatic electronic flash light device, an integrating circuit which integrates the amount of light reflected from an object to be photographed is started by a signal delayed from a trigger signal of a flash tube.

Abstract: A flash tube (speed-light) apparatus is provided with a drive circuit for ionizing gas in the flash tube in response to a triggering voltage produced by a trigger coil, and a light-measuring circuit measures the light emitted by the flash tube and reflected by an object to be photographed and controls the quantity of light emitted by the flash tube. The drive circuit comprises delay means that delays the flash emission by a predetermined delay time commencing with the energizing of the trigger coil. The delay time is selected longer than a period during which the light-measuring circuit is affected by noise generated by the energizing of the trigger coil.

Abstract: In an electronic flash of the type having a main flash capacitor, a trigger circuit, a flash lamp which is ignited by a trigger voltage from the trigger circuit and flashed by the discharge of electrical energy stored in the main flash capacitor, a light reception circuit for integrating the amount of light reflected back from a subject and a flash duration control circuit or a flash interruption circuit actuable when the amount of light integrated by the light reception circuit reaches a predetermined level, a DC power source is connected to the light reception circuit through a switching means which is enabled or closed in response to the flashing of the flash lamp, whereby the erratic operation of the light reception circuit due to the integration of light other than the flash of light reflected from the subject may be avoided.

Abstract: In a photographic flash device comprising a main capacitor (1) for storing a large electric energy, a gas-discharge flash tube (4) to be lit by the electric energy of the main capacitor (1), a switching circuit (5+9) which switches off the discharging of the flash lamp (1), a control circuit (20) which controls the switching circuit (5+9) in a manner to switch the switching circuit (5+9) off at a sending of a stopping signal from a triggering circuit (20) to the switching circuit (5+9), and a timer circuit which controls, responding to a selected guide number (G.N.) of flash photographing, the time period from the start of flashing of the flash tube (4) to a sending of a stopping signal to the control circuit (20) (namely the time period of flashing), the improvement is that the time period is adjusted responding to the voltage across the main capacitor (1).

Abstract: A semiconductor switching element is connected in series with a flash tube to stop emission of flash light therefrom during operation of the flash tube. A first and a second integrating circuit are parallelly arranged to be connected either alternatively, or both together, with the switching element. The first integrating circuit integrates photo-current generated by a photocell receiving light from an object illuminated by the flash light, and the second integrating circuit integrates current that is manually adjustable. When both integrating circuits are connected with the switching element, the switching element is turned off by that integrating circuit which first reaches a predetermined trigger level.

Abstract: A light detecting and measuring device for use with an electronic flash unit comprises a phototransistor, integrating capacitor and diodes connected in circuit to the flash unit. The diodes and capacitor are connected to the phototransistor and responsive to signals from the flash unit for enabling measurement of light by the phototransistor only while the flash unit is operating thus preventing measurement from external light sources.

Abstract: An electronic flash unit has a safety circuit for removing stored electrical energy that is potentially hazardous to a flash unit user. A switch, responsive to opening of the flash unit housing, is closed to energize a quench circuit, which is parallel to a chargeable flash firing capacitor. The firing capacitor discharges through the quench circuit, thereby lowering the stored electrical energy to a level that is not hazardous to an operator.

Abstract: An external sensor which may be detachably electrically connected to an electronic flash of the type having a flash duration control circuit for controlling the flash duration of a flash tube which flashes by discharging the electrical energy stored on a main capacitor, the external sensor including a light receiving unit which, in the automatic flash exposure mode, receives the light emitted from the flash and reflected back from a subject. In the automatic flash exposure mode in which the flash duration control circuit is activated in response to an interrupt signal from the light receiving unit, the external sensor selectively displays correct flash exposure data such as film speed, aperture and distance to a subject.

Abstract: An electronic flash device comprising a DC-DC converter circuit which converts a low voltage DC source to a high voltage DC current for charging a main discharge capacitor, a flash discharge tube which is adapted to flash by means of the energy stored in the main discharge capacitor, and a display circuit. The DC-DC converter circuit includes an oscillation transformer having a primary winding, a secondary winding magnetically connected with the primary winding, an auxiliary winding and further a second auxiliary winding, an oscillation transistor, and an auxiliary capacitor connected with the auxiliary winding for causing the oscillation transistor to be started; and the display circuit is lit for display when the voltage generated across the second auxiliary winding and the voltage applied across the auxiliary capacitor are superposed to reach a predetermined value.

Abstract: An electronic flash of the type incorporating the so-called variable guide number device or a flash duration control device for controlling the quantity of a flash of light emitted from a flash lamp. In an integrating circuit of the variable guide number device diodes are used so that their forward bias characteristics may be utilized for the accurate control of a flash duration.

Abstract: A photographic data recording device for a camera for photographically recording some data on film together with a photographic image. The device includes a capacitor, a charging circuit for the capacitor which responds to the release of the shutter for commencing charging and an electronic flash device operating in response to the capacitor discharge to illuminate the data. A control device automatically causes the capacitor to discharge electricity to allow the electronic flash device to emit a flash when the charge of the capacitor reaches a preset level of potential and which prevents the capacitor from discharging when the charge is below the preset level of potential. A display lamp may be utilized to indicate when the charged voltage of the capacitor reaches a preset level.

Abstract: A device for controlling the termination of light emission by a flash device including means for detecting the light reflected from the subject being illuminated by the flash, integrating means connected to the detecting means for providing a flash termination signal when the total amount of light received by the detecting means reaches a predetermined value, and flash termination means connected to the integrating device and to the flash device for terminating the delivery of electrical energy to the flash device when the signal from the integrating device reaches its predetermined value. The flash termination device is preferably constituted by a novel gas-filled, arc-producing element having identical, unpolarized electrodes and an internal or external triggering electrode.

Abstract: In a flash unit, wherein completion of the charging of a main capacitor from a DC-DC converter is indicated by a first indicator connected to the converter by a first voltage dividing circuit, there is provided a second voltage dividing circuit connected to the DC-DC converter and a switching circuit disposed between the second voltage dividing circuit and the first indicator so that an output voltage sufficient to energize a second (separate) indicator reliably is produced from the second voltage dividing circuit upon operation of the first indicator.

Abstract: In a flash discharge device including a strobe tube attached to a camera body, use is made of both the positive and negative outputs of a blocking oscillator. One output is used for charging a main capacitor to supply power to actuate the strobe tube, and the other output is used for energizing one or more indicators. Both the outputs may be used to accelerate the charging of the capacitor. The indicator energized by the output of the blocking oscillator while the main capacitor being charged may be an indicator which indicates that condition by intermittent lighting.