GB2115181A - Electric flash apparatus - Google Patents

Abstract

Electronic flash apparatus has two flash sources 16 and 18 for illuminating the subject directly and indirectly respectively. The light from the first flash source 16 is directed onto the subject by an adjustable mirror (Fig. 1) or by a diffusing plate 203 (Fig. 6) to vary the area illuminated directly. The light output of source 16 is less than that of source 18. Circuitry for controlling the triggering and quenching of the source is described. <IMAGE>

Description

SPECIFICATION Electric flash apparatus The present invention relates to electric flash apparatus and, more particulary, to electric flash apparatus for use of optical apparatus such as a photographic device.

In recent years, flash apparatus has been widely employed in various kinds of optical apparatus requiring flashlight. Particularly, in the art of photography, artificial light is commonly used to illuminate an object to be photographed. One form of artificial light which is now widely used is that produced by the so-called electric flash device. In such devices, a flash tube is provided in order to illuminate the object to be photographed, but the arrangeltnent is such that the light from the flash tube will illuminate only the object; if the surface of the object is contoured the illumination of the surface is uneven. Furthermore, when the flashlight from the photoflash is employed as direct illumination for the photographic object in a room or a photostudio, a shadow of the photographic object is commonly formed behind producing poor photographic results.

In order to alleviate these disadvantages of photoflash devices, it is known to use reflected, or bounced light to illuminate the object. In taking a picture by means of bounced light, there are still problems however, in that the quantity of light incident on the photographic object is much reduced from the predetermined value to which the device is set, particularly when a reflecting surface such as a ceiling surface is not white, and in that an object having an uneven surface cannot be photographed so well, because a significant portion of the light reflected from the object is not incident on the film in the camera.

To alleviate these disadvantages expensive illuminating equipment is required such as a front light, an umbrella-shaped reflecting plate and a backlight for eliminating the shadow from the background of the photographic object. This equipment, as well as being expensive is also bulky.

In order to alleviate further these disadvantages, a flash apparatus having two flashing members has been proposed, one of which is used to generate a direct light with respect to an object to be photographed and the other is employed to produce a bouncing light with respect to the object. According to thus flash apparatus, the clear photographing of a face of a man can carry out by eliminating the shadow from the background of the photographic object and is convenient to the photographing since the catch light is obtained.

Thus flash apparatus, however, has disadvantages that the shadow from the background is not eliminated completely.

An object of the invention is to provide an electric flash apparatus which performs good flashing operations.

Further object of the invention is to provide an electric flash apparatus which is reliable and economical.

Other objects and features will be in part apparent and in part pointed out hereinafter.

According to the present invention, an electric flash apparatus comprises a first flashing member including at least one first flash tube, a second flashing member at least one second flash tube, means for making illumination area of the flash light increase, and flash control arrangement having means for stopping a flashing, said flash control arrangement includes an electric charge storing circuit having at least one main storage capacitor for supplying an electrical energy, triggering means for triggering said flash tube, and said flash tube circuit member comprising a flash timing control means for controlling flash timing such that flashlight durations of said first flash tubes become same and an approximately same.

Embodiments of the invention will now be described by way of examples with reference to the accompanying drawings, in which: Figure 1 is a perspective view of an electric flash device according to the present invention; Figure 2 is a detailed circuit diagram of a control circuit arrangement of an electric flash device according to the present invention; Figure 3 is an elevational side view explaining the operation of an electric flash device in accordance with the present invention when used in performance of bounced light flash photography; Figure 4 is a perspective view of an electric flash device according to the present invention; Figure 5 is a perspective view of an electric flash device according to the present invention; Figure 6 is a perspective view and an elevational side view of an electric flash device according to the present invention;; Figure 7 is a perspective view of an electric flash device according to the present invention; Figure 8 is a perspective view of an electric flash device according to the present invention; Figure 9 is a detailed circuit diagram of a control circuit arrangement of an electric flash device according to the present invention; Figure 10 is a detailed circuit diagram of a control circuit arrangement of an electric flash device according to the present invention; and Figure 11 is a detailed circuit diagram of a control circuit arrangement of an electric flash device according to the present invention.

With reference to Fig. 1 of the drawings, there is shown, greatly simplified, an electric flash device according to the present invention. The electric flash device has a flash housing, generally designated by numeral 10 and consisting of a first casing 11 and a second casing 1 2. The second casing 1 2 is pivotally connected to the first casing 11 by means of a pivotable connecting member (not shown in the drawings). The connecting member forms part of a ratch mechanism and includes a pin which is fixed on the second casing 1 2 and which is pivotably engaged with the first casing 11.The ratch mechanism includes a ratch gear which is fastened to the second casing 1 2 together with the pin, a curved U-shaped plate spring carried in the first casing 11 and a pawl segment which is provided between the plate spring and the ratch gear. Accordingly, the second casing 1 2 is rotatable as is shown in by an arrow 1 3 with respect to the first casing 11.The first casing 11 is equipped with a light sensitive element 1 5 and, recessed in a front surface thereof, a first flash member 1 6 which includes a first flash tube 1 7. The second casing 12 is equipped with a second flash member 1 8 which includes a second flash tube 1 9. Accommodated in the housing 10 is a flash control circuit arrangement which is constructed as shown in Fig. 2.

The flash apparatus of the present invention further comprises means for making an illumination area of flash light increase. The means for making an illumination area increase comprises an illumination area increasing member 200 which is constructed by a reflecting plate 201 fastened to the first casing 11 by a fastening member 202.

The flash control circuit arrangement comprises a direct current power source circuit A, a converter circuit B for converting and boosting a direct current voltage from the direct current power source circuit A to an alternating current voltage, a rectifier circuit C for rectifying the alternating current voltage from the converter circuit B, an electric charge storing circuit D for supplying the electrical energy to the flash tubes 1 7 and 19, a trigger signal generating means for triggering a flash tube circuit member, a switching circuit G for actuating the flash tube circuit member, a quenching trigger signal generating circuit I for actuating the quenching circuit H, and a oscillation control circuit J for controlling oscillating operation of the converter circuit B.

The flash tube circuit member consists of the flash tube 1 7 and the second flash tube 1 9.

The trigger signal generating means consists of a first trigger pulse generating circuit E for triggering the first flash tube 1 7 and a second trigger pulse generating circuit F for triggering the second flash tube 1 9.

In more detail, the power source circuit A includes a battery 20 and a manually operated switch 21 connected in series with the battery 20. The converter circuit B comprises, substantially, an oscillator circuit OC. In more detail, the voltage converter circuit B includes a resistor 22 of which one terminal is directly connected to the negative terminal of the battery 20, an oscillating transformer 24, an oscillation switching element in the form of a transistor 25. The oscillating transformer 61 consists of a primary winding 61a, a secondary winding 61b and a third winding 61c.

One terminal of the primary winding 24a is directly connected to the negative terminal of the battery 20, and other terminal of the primary winding 24a is connected to a collector electrode of the transistor 62 in order to form the oscillator circuit OC. One terminal of the secondary winding 61 b is connected to a base electrode of the transistor 25. The rectifier circuit C comprises an electric valve in the form of a diode 63a of which anode electrode is connected to a terminal of the secondary winding 61 b of the oscillating transformer 61.

The electric charge storing circuit D comprises a main storage capacitor 64, and an indicating lamp 67 for indicating the charging. The main storage capacitor 64 is connected to a cathode electrode of the diode 63a.

The second trigger signal generating circuit E2 includes a trigger resistor 68, a synchronizing switch 69, a resistor 70, a trigger capacitor 71 and a trigger transformer 72. In the second trigger signal generating circuit E2, one terminal of the trigger resistor 68 is connected to a cathode electrode of the diode 63a. One terminal of the trigger capacitor 71 is connected to the other terminal of the resistor 68 and an input winding 72a of the trigger transformer 72 is connected to the other terminal of the trigger capacitor 71. The trigger transformer 72 comprises the input winding 72a, an output winding 72b.

The first trigger signal generating circuit E, includes a trigger resistor 73, a trigger capacitor 76 and a trigger transformer 77. In the first trigger signal generating circuit E, one terminal of the trigger resistor 73 is connected to a negative terminal of the diode 63a. One terminal of the trigger capacitor 76 is connected to the other terminal of the resistor 73, and an input winding 77a of the trigger transformer 77 is connected to the other terminal of the trigger capacitor 76 by way of a synchronous switch 69. The first trigger signal generating circuit E1 is connected to the second trigger signal generating circuit E2 by way of changeover switches 69a and 69b which are interlocked with the power source circuit 21.

The switching circuit G includes a switching element in the form of a first thyristor 78, a gate resistor 79, a capacitor 80 and resistors 81 and 82. The first thyristor 78 is connected in series with the first flash tube 1 7 and the second flash tube 1 9 of the flash tube circuit member. The capacitor 80 is connected between an anode electrode and a cathode elec trode across the resistor 45.

The flash tube circuit member comprises a first flash tube 17, a second flash tube 1 9.

The first flash tube 1 7 is provided with a pair of main current conducting electrodes 17a, 1 7b and a trigger electrode 1 7c which is also positioned adjacent but external to the flash tube 1 7. The second flash tube 1 9 is also provided with main current conducting electrodes 19a, 1 9b and a trigger electrode 1 9c which is also positioned adjacent but external to the flash tube 1 9. As explained in the foregoing in Fig. 1, the first flash tube 1 7 is arranged in the first flash member 1 6 which is recessed in a front surface of the first casing 11, and the second flash tube 1 9 is arranged in the second flash member 1 8 mounted on an end portion of the second casing 1 2. One main current conducting electrode 1 7a of the first flash tube 1 7 is connected to one electrode of the main storage capacitor 64 by way of an impedance element in the form of a coil 93, and other main current conducting electrode 1 7b is connected to the anode electrode of the first thyristor 78 of the switching circuit G.The trigger electrode 1 7c of the first flash tube 1 7 is connected one terminal of an output winding 72b of trigger transformer 72.

One main current conducting electrode 1 9a of the second flash tube 1 9 is connected to the one electrode of the main storage capacitor 64, and the other main current conducting electrode 1 9b is connected to the anode of the first thyristor 78 together with the main current conducting electrode 1 7b of the first flash tube 1 7 and, therefore, electrodes 1 7b and 1 9b are connected to other electrodes of the main storage capacitor 64 by way of the first thyristor 78.

The quenching circuit H comprises a second thyristor 83A connected in parallel with the flash tube circuit F by way of a resistor 84 and a capacitor 95" The quenching signal generating circuit I comprises a light sensitive element in the form of a phototransistor 47, an integrating capacitor 103 connected to the phototransistor 47 by way of an integration resistor to form an integration circuit L1, a transistor 98, a diode 99, resistors 96, 101, 102, 104 and 105, and is connected as shown.

The oscillation control circuit J comprises a transistor 106 of which a collector electrode is connected to the quenching signal generating circuit I, an oscillation control capacitor connected between the electric charge storing circuit D and a base electrode of the transistor 106 by way of a resistor 107, and parallelly connected capacitor 109 and a resistor 110.

A circuit constructed in accordance with the foregoing description operates as follows.

When the power source switch 21 is made ON, both of the changeover switches becomes ON together with the power source switch 21.

Under these conditions, the converter circuit activates an oscillating operation, and thereby a high voltage is induced at the secondary winding 61b of the oscillating transformer 61.

The boosted alternating current voltage is rectified by the rectifier circuit C, and thereafter electric charge is stored on the main storage capacitor 64. When the main storage capacitor 64 is fully charged up to a predetermined voltage, the neon glow lamp 67 lights indicating that the device is readiness for the flash tubes 1 7 and 1 9 to be fired. Simultaneously the triggering capacitors 71 and 76 are charged by the high DC voltage from the rectifier circuit C.In such conditions, the operation of the flash tube member is initiated by closing of the switch 69 of the second trigger signal generating circuit E2 in synchronism with the camera opening operation, enabling flash tubes 1 7 and 1 9. When the flash tubes 1 7 and 1 9 flash, the quench signal generating circuit I activates to turn the second thyristor 83A ON and thereby to turn the first thyristor 78 OFF. When the first thyristor 78 becomes OFF, flashing of the flash tubes 1 7 and 1 9 are stopped at the approximately same time and/or at the same time by the aid of the coil 93.Further, when the electric charge of the main storage capacitor discharges across the flash tubes 1 7 and 19, a negative voltage is applied to the base of the transistor 106 and the transistor 106 becomes conductive. When the transistor 106 becomes ON, the base electrode of the oscillating transistor 62 is by-passed and thereby the transistor 62 is made OFF to stop the oscillating operation of the oscillator circuit OC.

Fig. 3 shows an example of bounce photographing in a room or photo-studio, by using the electric flash apparatus in accordance with the present invention. As is best shown in Fig.

3, the first flashing member 1 6 of the first casing 11 is directed toward an object to be photographed such as, for example, a man 55. The second casing 1 2 is set with a suitable angle with respect to the first casing 11, and the second flashing member 1 8 is directed toward a celling 56 with a desired angle with respect to a surface of the celling 56, in order to apply the reflected flash light to the object to be photographed. That is to say, a flash light 58 from the first flashing member 1 6 is directed toward the man 55, and, on the other hand, a flash light 59 from the second flashing member 1 8 is directed toward the surface of the ceiling 56. The flash light 59 reflects at the surface of the celling 56 and forms the bounce light. One reflected light 59a of the flash light 59 incidents on the man 55, and other reflected light 59b of the flash light 59 incident on a background such as, for example, a wall 57 of the room. The one reflected flash light 59a is superimposed with the flash light 58 from the first flashing member 1 6 and, on the other hand, the reflected light 59b gets rid of the shadow in the background of the man 55.

As discussed in the foregoing, quantity of the flash light 59 is set so as to be greater than that of the flash light 58 produced from the first flash tube 1 7 by connecting the current-limiting coil 93 thereto (see Fig. 2).

The flash light from the first flashing member 16 is directed toward the reflecting plate 201 and thereafter the illuminating area is increased to decrease the shadow of the man 55. Accordingly, the boundary of the shadow becomes unclear and thereby good photographing can be carried out.

Accordingly, the photographing mode brightness in the object to be photographed such as the man 55 increases and is made uniform. The flash durations of the first flash tube 1 7 and the second flash tube 1 9 is determined to the time interval. The time interval is preselected in synchronism with the shutter operation of the camera. The flash durations of the tubes 1 7 and 1 9 are synchronized and set at the given time point, and each of the tubes 1 7 and 1 9 are simultaneously extinguished at the same time by the aid of the coil 93.Accordingly, the unnecessary flashing of the tubes 1 7 and 1 9 are avoided and, therefore, the flashing performance is enhanced, and thereby the rated capacity of the main storage capacitor 23 is made small, although the apparatus is equipped with the first flash tube 1 7 and the second flash tube 1 9. Furthermore, as the total quantity of the flash light is summed by the light from first flashing member 1 6 and the second flashing member 18, the total quantity of light incident on the photographic object and, as a result, the catch light is duely obtained in the photographic object.

The electric flash apparatus described hereinabove and illustrated by the Figures has the advantage of being very certain in operation and of enabling numerous discharges of flash tubes to be effected without replacing the various elements.

The electric flash apparatus described hereinabove has, moreover, advantage that the circuit construction is simplified and smallized, since the switching circuit D is commonly and effectively used for a plurality of flash tubes of the flash tube circuit E.

As is apparent from the hereinabove description, according to the present invention, the following advantages are obtained.

An advantage over the prior art flash apparatus is that the invention provides a new electric flash apparatus which can perform the bounce photographing by means of setting an angle between a first casing and a second casing to the desired value since the first casing and the second casing are rotatably connected to each.

Another advantage of the invention is that both of a first flashing member and a second flashing member can also be used as a directlight source by directing the both of them toward the object to be photographed and, as a result, the quantity of an incident light to the object increases to that extent.

A further advantage of the invention is than an electric flash apparatus is convenient to take a photograph, particularly to taking a picture by employing a bounce light because a flash housing is rotatably constructed by a first casing and a second casing, each of the casing has a flashing member.

Fig. 4 shows a modification of the flash apparatus of Fig. 1. As is shown in Fig. 4, a reflecting plate 201 is secured to a second casing 1 2 of the flash housing 10, and a first flashing member 1 6 is movably mounted on a front surface of the first casing 11. The first flashing member 1 6 is movable toward upper and lower directions with respect to the first casing 11. Accordingly, an illumination area of the flash light 58 is increased and is adjustable. In accordance with the flash apparatus of Fig. 4, same functions and advantages are obtained.

Fig. 5 shows another embodiment of the flash apparatus according to the present invention. As is shown in Fig. 5, a first flashing member 1 6 is rotatably mounted on a first casing 11 of the flash housing 10 by a fastening member 60A. In more detail, the first flashing member 1 6 is constructed by a fastening frame 60A projected from a front surface of the first casing 11 and a flashing unit 16A. One end portion of the flashing unit 1 6A is rotatably connected to one end portion of the fastening frame 60A. An illumination area increasing member 200 consists of a reflecting plate made of a metallic material, a plastic or the like and having a wider area than that of the flashing unit 16A.One edge portion of the reflecting plate is rotatably connected to one edge portion of the front surface of the first casing 11. According to the flash apparatus of Fig. 5, it is very convenient to take a photograph in a longitudinal direction of a film.

Fig. 6 shows the other possible embodiment of a flash apparatus of the invention. In the flash device of Fig. 6, a first flashing member 1 6 comprises a flashing unit 60B mounted on a side surface of a first casing 11 by a connecting member 60B. The connecting member 60B is disengageably fastened to one side surface of the first casing 11 so as to project toward an outer direction of the first casing 11. One end portion of the flashing unit 1 6B is connected to the connecting member 60B. An illumination area increasing member 200 comprises a light diffusing plate 203 which is positioned in a front side of a first flashing member 16. One edge portion of the diffusing plate 203 is connected to the edge of the first casing 11.A flashlight generated from the first flashing member 1 6 is diffused by the diffusing plate 203. An area of a diffused light 58B becomes wider than that of the flashlight of the flashing unit 16B.

Fig. 7 is a modification of the flash apparatus of Fig. 6. As is shown in Fig. 7, an illumination area increasing member 200 is positioned to a front side so as to be opposed to a first flashing member 16. A diffusing plate 203 is fastened by a connecting member 60c. A diffusing light 58c is directed toward a photographic object.

Fig. 8 shows an embodiment of an electric flash apparatus of the present invention. In accordance with the flash apparatus of Fig. 8, each of flashing members is mounted on a camera 300. A first flashing member 1 6 is mounted on a top surface of the camera 300, and a second flashing member 1 8 is fastened to the camera 300 by a grip 312. The second flashing member 18 is provided a casing 1 2A secured to the grip 312 and a casing 15B rotatably connected to the casing 15A. The flash apparatus of Fig. 8 is convenient to make the camera 300 small size.

Fig. 9 shows other embodiment of the flash control arrangement employed in the invention.

As is best shown in Fig. 2, the flash control circuit arrangement comprises a power source circuit A, an electric charge storing circuit D for supplying the electrical energy to the flash tubes 1 7 and 19, a trigger pulse generating circuit E for triggering the flash tube member, a flash tube circuit F for generating a flash light, a switching circuit G for actuating the flash tube circuit F, a quenching circuit H for extingùishing the flash tubes of the flash tube circuit F, a quench trig er signal generating circuit I for actuating the quenching circuit H and a light-sensitive circuit L1 for actuating the quench trigger signal generating circuit I.

In more detail, the power source circuit A includes a battery 20, a manually operated switch 21 and a resistor 22 connected in series with the battery 20 by way of the switch 21. The electric charge storing circuit D comprises a main storage capacitor 23 which is connected in parallel relationship to the battery 20 through the switch 21 and the resistor 22 and a charging level indicating lamp in the form of a neon tube 25 which is connected in parallel with the main storage capacitor across a resistor 25. When the main storage capacitor 23 is charged up to a predetermined charging voltage, the neon tube 25 luminesces and indicates the readiness for flashing.

The trigger pulse generating circuit E includes a trigger resistor 26, a trigger capacitor 27 and a trigger transformer 28. In the trigger pulse generating circuit E, one terminal of the trigger resistor 26 is connected to a positive terminal of the battery 20 by way of the resistor 22 and the switch 21. One termi nal of the trigger capacitor 27 is connected to the other terminal of the resistor 26 and an input winding 28a of the trigger transformer 28 is connected to the other terminal of the trigger capacitor 27 The switching circuit G includes a trigger capacitor 29, a second trigger transformer 30, a synchronizing switch 31 and a switching element in the form of a first thyristor 32, a protecting resistor 33, a gate resistor 34, a capacitor 35 and a resistor 36.The trigger capacitor 29 is connected to the trigger resistor 26, and an input winding 30a of the pulse transformer 30 is connected between an input winding 28a and capacitor 29. The synchronizing switch 31 is interposed between a juncture of the resistor 26 and the capacitor 27 and a juncture of the input windings 28a and 30a. The protecting resistor 33 is interconnected between a negative terminal of the battery 20 and a juncture of the synchronizing switch 31 and the input winding 30a of the pulse transformer 30. An output winding 30b of the pulse transformer 30 is connected between a gate electrode and a cathode electrode of the first thyristor 32 through the gate resistor 34. The switch 31 is mounted on a camera, and is closed in synchronism with a camera shutter opening operation, enabling flash tube to be fired by the well-known operation of flash trigger circuit.

The flash tube circuit F comprises a first flash tube 17, a second flash tube 1 9 and a current-limiting resistor 37 for restricting flash current flowing through the first flash tube 17.

The first flash tube 1 7 is provided with a pair of main current conducting electrode 17a, 1 7b and a trigger electrode 1 7c which is positioned adjacent but external to the flash tube 1 7. The second flash tube 1 9 is also provided with a pair of main current conducting electrodes 19a, 1 9b and a trigger electrode 1 9c which is also positioned adjacent but external to the flash tube 1 9. As ex plained in the foregoing in Fig. 1, the first flash tube 1 7 is arranged in the first flashing member 1 6 which is mounted on the surface of the first casing 11, and the second flash tube 1 9 is arranged in the second flashing member 18 mounted on an end portion of the second casing 1 2. One main current conduct ing electrode 1 9a of the second flash tube 1 9 is connected to one electrode of the main storage capacitor 23, and the other main current conducting electrode 1 9b is connected to an anode electrode of the thyristor 32 of the switching circuit G. The trigger electrode 1 9c of the second flash tube 1 9 is connected to one terminal of an output winding 28b of trigger transformer 28. One main current con ducting electrode 1 7a is connected to the one electrode of the main storage capacitor 23 through the current-limiting resistor 37, and the other main current conducting electrode 1 7b is connected to the anode of the thyristor 32 together with the main current conducting electrode 1 9b of the second flash tube 1 9 and, therefore, the electrode 1 7b and 1 9b are connected to the other electrode of the main storage capacitor 23 by way of the first thyristor 32.The trigger electrode 1 7c of the first flash tube 1 7 is connected to the output winding 20b of the trigger transformer 28 together with the trigger electrode 1 9c of the second flash tube 19, thence the first flash tube 1 7 and the second flash tube 1 9 are simultaneously triggered by the triggering signal from the triggering pulse generating circuit C.

There are certain criteria, in the flash tube circuit F, that must be met in both flash tubes 1 7 and 1 9. To operate effectively, the current to be supplied to the first flash tube 1 7 must be a relatively low value compared with that to be supplied to the second flash tube 19, in order to make the quantity of the flash light generated from the first flash tube 1 7 to smaller than that of the flash light from the second flash tube 1 9. To perform this requisition, the first flash tube 1 7 must have a relatively low impedance compared with the second flash tube 1 9. To provide such low impedance, the first flash tube 1 7 should have a low gas pressure and a short electrode spacing. On the other hand, when the first flash tube 1 7 has a low impedance compared with the second flash tube 19, an initiation of flashing of the first flash tube 1 7 occurs earlier than that of the second flash tube 1 9.

To supply such low current and to adjust the flash durations of the flash tubes 1 7 and 19, the current-limiting resistor 37 is connected to the first flash tube 1 7. Additionally, although the flash tube circuit E employs the resistor 37 as the current-limiting element, the invention is not limited to this, and a chorked-coil may also be employed.

The quenching circuit H includes a quench tube 38 for quenching the flash tubes 1 7 and 1 9, a resistor 39, a commutation capacitor 40 and a commutation resistor 41. The quench tube 38 is connected to both electrodes of the main storage capacitor 23 through the resistor 39. The commutation capacitor 40 is connected between a juncture of the resistor 39 and the quench tube 38 and the anode electrode of the thyristor 32, and the commutation resistor 41 is connected in parallel relationship to the thyristor 32 between the anode electrode and the cathode electrode thereof.

There are, of course, certain criteria that must be met in quench tube 38. To operate effectively, the quench tube 38 must have a further low impedance compared with the second flash tube 1 9. The second flash tube 19 has a minimum impedance of typically 1.5 to 2 ohms. Thus, the quench tube 38 should have an impedance near 0.1 ohm. To provide such low impedance, the quench tube 38 also should have a low gas pressure and a short electrode spacing. The electrodes 38a and 38b must be capable of carrying a very high current for short time. The tube 38 must be capable of being triggered rapidly and easily into conduction over the range which voltage of the flash tubes 1 7 and 1 9 changes during the flash. The quench tube includes a trigger electrode 38c spaced midway between the two main electrodes 38a and 38b.

The quench trigger signal generating circuit I comprises a quench trigger transformer 42, two series connected resistors 43 and 44, a second switching element in the form of the thyristor 45 whose anode electrode is connected to an input winding 42a of the quench transformer 42, and a quenching capacitor 46 which is connected in parallel with the resistor 44. An output winding 42b of the quenching transformer 42 is interconnected between the trigger electrode 38c of the quench tube 38 and a juncture of the input winding and the anode electrode of the thyristor 45.

The light sensitive circuit L1 comprises a light sensitive element in the form of a photocell 47, a capacitor 48 whose one electrode is connected to the positive electrode of the battery 20, a Zener diode 49 connected between the capacitor 48 and the photocell 47, a gate resistor 50 connected to a gate electrode of the thyristor 45 and the photocell 47, parallelly connected resistor 51 and capacitor 52, and a protecting resistor 53.

A circuit constructed in accordance with the foregoing description operates as follows.

When the switch 21 is closed, the electric charge is stored on the main storage capacitor 23 from the battery 20 by way of the switch 21 and the resistor 22. Simultaneously the triggering capacitors 27 and 29 are charged from the battery 20 through the trigger resistor 26. The electric charge is also accumulated on the capacitors 40, 46 and 48 from the battery 20. In thus conditions, the operation of the flash tube circuit E is initiated by the closing of switch 31 of the switching circuit D in synchronism with the camera shutter opening operation, enabling flash tubes 17 and 19.When the switch 31 is closed, the electric charge of the trigger capacitor 27 is discharged through the switch 31 and the input winding 28a of the trigger transformer 28, and the electric charge of trigger capacitor 29 is simultaneously discharged through the switch 31 and the input winding 30a of the trigger transformer 30. By the discharge of capacitor 27, a triggering pulse is generated from the output winding 28b of the trigger transformer 28. And, at the same time, a gating pulse appears from the output winding 30b of the pulse transformer 30, by discharging of the capacitor 29.

The stored voltage on the main storage capacitor 23 also appears across the electrodes 1 7a and 1 7b of the first flash tube 1 7 and across the 1 9a and 1 9b of the second flash tube 19.

The triggering pulse from the output winding 28b of the trigger transformer 28 is applied to the trigger electrode 1 7c and 1 9c of the tubes 1 7 and 1 9. The firing pulse from the output winding 30b of the trigger transformer 30 is applied to the gate electrode of the first thyristor 32 and the thyristor 32 is turned on.When the thyristor 32 becomes conductive, the first flash tube 1 7 initiates a flash discharge between the electrodes 1 7a and 17b, and, at the same time the second flash tube 1 9 also initiates a flash between the electrodes 1 9a and 19b, because each trigger electrode 1 7c and 1 9c is commonly connected to the output winding 28b of the trigger transformer 28.Under normal operations heretofore, the flash continues until the main storage capacitor 23 has discharged through the tubes 1 7 to 1 9 to the point where the voltage will no longer support the flash across the tubes 1 7 and 1 9. That usually requires about several millisecond of time.

The light sensitive circuit L1 senses the flash light from the tubes 1 7 and 19, and automatically adjusts the maximum time duration of the flash produced across the tubes 1 7 and 1 9. The maximum time duration of flash remains at that time determined by the discharge of the main storage capacitor 23 through the first and the second flash tubes 17 and 19.

More specifically, when the flash light is reflected into the photocell 47 from the object being photographed, the resistance of the photocell 47 decreases rapidly following the incident flash of light. Since the decay time of the conductivity of photocell 47 is low relative to the flash interval, the photocell 47 in and of itself effectively integrates the incident light, converting that incident light into a voltage signal of increasing magnitude appearing at the protecting resistor 53, thence to the Zener diode 49. When the signal at Zener diode 49 has reached a predetermined and fixed breakdown voltage, the Zener diode 49 becomes suddenly conductive and a voltage is developed across the resistor 50 producing a sharp pulse of energy to the gate electrode of the thyristor 45.The sharp pulse applied to the gate electrode of the thyristor 45 causes that thyristor 45 to become suddenly conductive, effectively short-circuiting the capacitor 48. This, in turn, causes the capacitor 48 to discharge, thereby applying a sharp pulse of energy to the input winding 42a of the quench transformer 42. The transformer 42 transmits the triggering pulse from the output winding 42b thereof to the triggering electrode 38c of the quench tube 38.

That triggering pulse causes the quench tube 38 to become instantaneously conductive.

When the quench tube 38 becomes conductive, electric charge of the commutation capacitor 40 also discharges through the quench tube 38 and the commutation resistor 41, and thereby the voltage is induced between both terminals of the commutation resistor 41 so as to be positive polarity at the cathode electrode side of the first thyristor 32, after a time interval decided by a time constant of the capacitor 40 and the resistor 41.

This induced voltage at the resistor 41 causes the first thyristor 32 to turn off. When the first thyristor becomes non-conductive, the first and the second flash tubes 1 7 and 1 9 are simultaneously and instantaneously extinguished, because the main current conducting electrode 1 7b and 1 9b of each flash tubes 1 7 and 1 9 are commonly connected to the anode electrode of the first thyristor 32.

In this case, since the quench tube 38 is the much lower impedance, when conductive, than do the first flash tube 1 7 and the second flash tube 19, almost all of the stored energy in the main storage capacitor 23 is discharged through the current-limiting resistor 39 and the quench tube 38, causing the first flash tube 1 7 and the second flash tube 1 9 to be extinguished at such time as sufficient light has been reflected on to the photocell 47 to effect the initiation of the quenching.

Fig. 10 shows other embodiment of a control circuit arrangement of the invention.

The flash control circuit arrangement comprises a direct current power source circuit A, a converter circuit B for converting and boosting a direct current voltage from the direct current power source circuit A to an alternating current voltage, a rectifier circuit C for rectifying the alternating current voltage from the converter circuit B, an electric charge storing circuit D for supplying the electrical energy to the flash tubes 1 6 and 18, a trigger pulse generating means for triggering a flash tube circuit member, a switching circuit member for actuating the flash tube circuit member, a quenching circuit member for extinguishing the flash tube circuit member and a quench trigger signal generating circuit member for actuating the quenching circuit member.

The flash control circuit arrangement further comprises a voltage generating circuit S activated by an activation signal from the trigger signal generating circuit member and generating voltage signal, a light receiving circuit L, for sensing a flash light generated from the flash tube circuit member and reflected from an object to be photographic and conducting in response to the reflected light quantity, an integration circuit L2 in which the charging time interval changes corresponding to conduction of the light receiving circuit L1, a timer circuit T for controlling reset timing of the integration circuit L2, a reference voltage setting circuit M for setting a plurality of reference voltages, a comparator circuit N receiving a voltage signal from the integration circuit L2 and a reference voltage signal of the reference voltage setting circuit M, an amplifier circuit P for amplifying an output signal of the comparator circuit N, a time delay circuit Q for delaying the resetting operation.

The flash tube circuit member consists of a first flash tube circuit F, including a flash tube 1 6 and a second flash tube circuit F2 includ ing a second flash tube 1 8. The trigger signal generating means comprises a first trigger signal generating circuit E, for triggering the first flash tube 1 6 of the first flash tube circuit F, and a second trigger signal generating circuit E2 for triggering the second flash tube 18 of the second flash tube circuit F2.The switching circuit member comprises a first switching circuit G1 for controlling flash current of the first flash tube 1 6 and a second switching circuit G2 for controlling flash current of the second flash tube 1 8. The quenching circuit means comprises a first quenching circuit H, for controlling the switching operation of the first switching circuit G, and a second quenching circuit H2 for controlling the switching operation of the second switching circuit G2 The first trigger signal generating circuit E, includes a trigger resistor 68, a synchronizing switch 69, a trigger capacitor 71, a resistor 70 and a first trigger transformer 72. In the first trigger signal generating circuit E" one terminal of the trigger resistor 68 is connected to the cathode electrode of a diode 63a.One terminal of the trigger capacitor 71 is connected to the other terminal of the resistor 68 and the main storage capacitor 64 by way of the resistor 70. The first trigger transformer 72 comprises an input winding 72a and an output winding 72b. The input winding 72a is connected in parallel with the trigger capacitor 71 across the synchronizing switch 69.

The output winding 72b of the first trigger transformer 72 is connected to a trigger electrode 1 6c of the flash tube 16. The second trigger signal generating circuit E2 includes a trigger resistor 73, a second trigger capacitor 76, a second triggering transformer 77, a switching element in the form of a thyristor 74, a gate capacitor 75a and a trigger resistor 72. In the second trigger signal generating circuit E2, one terminal of the trigger resistor 73 is connected to the diode 63a, and the second trigger capacitor 76 is connected to the other terminal of the resistor 73. An input winding 77a of the second triggering transformer 77 is connected in parallel with the second trigger capacitor 76 by way of the switching element in the form of the thyristor 74.A capacitor 75a for preventing the noise and a resistor 75 for stabilizing the actuation of the thyristor 74 are connected between a gate electrode and a cathode electrode of the thyristor 74.

The voltage generating circuit S comprises a capacitor 70 which is connected to the diode 63a of the rectifier circuit C by way of a protecting resistor 114, a switching element in the form of a thyristor 11 5 of which an anode electrode is connected to a capacitor 11 3 by way of a protecting resistor 114 and a constant voltage generating element in the form of a Zener diode 11 6 which is connected between the thyristor 11 5 and the capacitor 11 3. The Zener diode 11 6 is connected to the light receiving circuit L,. the integration circuit L2, the timer circuit T, the reference voltage setting circuit M and the comparator circuit N.

The light receiving circuit L, comprises a light receiving element in the form of a phototransistor 47. The integration circuit L2 comprises a resistor 11 8 and an integration capacitor 11 9. The phototransistor 47 of the light receiving circuit L, is connected to the Zener diode 11 6 of the voltage generating circuit S by way of the diode 11 7. The integration capacitor 11 9 of the integration circuit L2 is connected to the phototransistor 47 by way of the integration resistor 11 8.

The integration reset timing circuit in the form of a timer circuit T comprises a. charging resistor 1 22 and a capacitor 1 23 which is connected to the voltage generating circuit S by way of the resistor 1 22. The reference voltage setting circuit M comprises a voltage divider 1 25 which is connected to a juncture of the thyristor 11 5 and the Zener diode 11 6 of the voltage generating circuit S by way of a variable resistor 1 26. The comparator circuit N N comprises a plurality of comparator ele- ments 1 27a and 127b, each of which is activated by different operation voltages such as, 2 volts and 2.5 volts.The comparator elements are, respectively, connected to the integration circuit L2 and the reference voltage setting circuit M. Each of the comparator elements 1 27a and 1 27b is set so as to be operated by the different voltage and is connected to corresponding taps of the resistor elements 1 26a and 1 26b of the voltage divider 1 26 and the integration circuit L2 and the integration reset circuit K.

The amplifier circuit P comprises an amplifier element 1 28a which is connected to the comparator element 1 27a and an amplifier element 1 28b which is connected to the comparator element 1 28b of the comparator circuit N. The time delay circuit Q comprises a resistor 1 29 connected to an output terminal of the comparator element 1 28b of the comparator circuit P, a capacitor 1 30 connected to the resistor and the capacitor 1 23 of the timer circuit T, and a diode 1 31 of which anode electrode is connected to a juncture of the resistor 1 29 and the capacitor 1 30 and of which a cathode electrode is connected to the base electrode of the transistor 121 of the integration circuit L2. The flash selecting circuit R comprises a first changeover switch 132, a blocking diode 1 33 and a resistor 1 36 and a diode 134.The changeover switch 132 has stationary contacts 1 32a and 1 32b and a movable contact 132c. The movable contact 1 32c of the first changeover switch 1 32 is connected to an output terminal of the first comparator element 128a. The movable contact 1 32a is connected to an anode electrode of the blocking diode 1 33 and an anode electrode of the diode 1 35. A cathode electrode is connected to the gate electrode of thyristor 83A of the first quenching circuit H, by way of the resistor 1 34. A cathode electrode of the diode 1 34 is connected to the gate electrode of the thyristor 74 of the second trigger signal generating circuit E2.

The second changeover switch 1 37 has a movable contacts 1 37a and 1 37b and a movable contact 137c. The movable contact 1 37c is connected to the output terminal of the second comparator element 1 28b by way of the diode 1 36. The stationary contact 1 37a is connected to the gate electrode of a thyristor 83b of the second quenching circuit H2 by way of a resistor 1 38. The stationary contact 1 37a of the second changeover switch 1 37 is connected to the thyristor of the first quenching circuit H, by way of the resistor 1 34.

A circuit constructed in accordance with the foregoing description operates as follows.

When the power source switch 21 is made ON, the voltage circuit B activates an oscillating operation, and thereby the high voltage is induced at a secondary winding 61 b of the transformer 61. The boosted alternating current voltage is rectified by the rectifier circuit C, and thereafter electric charge is stored on the main storage capacitor 64. When the main storage capacitor 64 is fully charged up to the predetermined voltage, the neon glow lamp 67 lights indicating that the device is readiness for the flash tube 1 7 and 1 9 to be fired. Simultaneously trigger capacitors 71 and 76 are charged by the high DC voltage from the rectifier circuit C.In such conditions, the operation of the flash tube member is initiated by closing of a switch 69 of the first trigger pulse generating circuit E1 in synchronism with the camera shutter opening operation, enabling the first flash tube 1 7 to fire.

When the switch 69 is closed, the electric charge of the trigger capacitor 33 is discharged through the switch 69 and the input winding 72a of the triggering transformer 72.

By the discharge of the capacitor 71, triggering pulses are generated from the output winding 76b and the detection winding 76c of the triggering transformer 72. The stored voltage on the first main storage capacitor 64 appears across the electrodes 1 7a and 1 7b of the first flash tube 1 7. The triggering pulse generated from the output winding 76b is applied to the trigger electrode 1 7c of the first flash tube 17, and thereby the first flash tube 1 7 is triggered.

The fifth thyristor 11 5 of the voltage generating circuit S is triggered and fired by a triggering signal from the detection winding 76c of the triggering transformer 76. By the firing of the fifth thyristor 76, a voltage of the capacitor 11 3 is applied to the Zener diode 11 6 to generate a predetermined constant voltage such as 20 volts. The constant voltage produced by the Zener diode 11 6 is applied to the light receiving circuit L1, the integration circuit L2, the reference voltage setting circuit M, the comparator circuit N and the timer circuit T.

Under these conditions, the phototransistor 47 of the light receiving circuit L, receives a reflected light which is produced by the first flash tube 1 7 of the first flash tube circuit F, and is reflected from the object to be photographed (not shown in Fig. 10) and becomes conductive in response to the quantity of the reflecting light. By the conduction of the phototransistor 47, electric charge is stored on the integration capacitor 11 9 of the integration circuit L2 and thereby the charging voltage of the integration capacitor 11 9 increases to a predetermined value which is corresponded to quantity of the flash light.

The charging voltage of the integration capacitor 11 9 is applied to the comparator circuit N.

On the other hand, the reference voltages setting circuit M produces a plurality of reference voltages to be applied to the comparator circuit N. In this instance, the reference voltage setting circuit M is set so as to produce the plurality of reference voltages such as, for example, 2 volts and 2.5 volts. The comparator circuit N comprises a comparator element 1 27a activated at 2 volts and a comparator element 1 27b activated at 2.5 volts.

When the charging voltage of the integration capacitor 11 9 attains to the predetermined value such as 2 volts, the comparator element 1 27a generates an amplifying output signal. The output signal of the first comparator element 1 27a is supplied to the thyristor 83A of the first quenching circuit H, through the diode 1 33 and 1 34 as the gating signal and, at the same time, is supplied to the thyristor 74 of the second trigger signal generating circuit E2 through the diode 135, enabling to be conductive the thyristors 83A and 79. By the conduction of the thyristor 83A of the first quenching circuit H1, and thereby the first flash tube 1 6 is simultaneously extinguished.

By the conduction of the thyristor 74 of the second trigger signal generating circuit E2, electric charge stored on the second trigger capacitor 76 is discharged through the input winding 77a of the second triggering transformer 77 and a high voltage pulse generates at the output winding 77b. The high voltage pulse produced at the output winding 77b is applied to the trigger electrode 1 8c of the second flash tube 19, and thereby the second flash tube 1 9 commences the flashing opera tion. In this case, the charging voltage of the integration capacitor 11 9 of the integration circuit L2 continues to increase.The phototransistor 47 further senses a reflected light which is generated from the second flash tube 1 9 of the second flash tube circuit F2 and is reflected from the object to be photographed.

The charging voltage further increases due to the reflected light of the second flash tube 1 9. When the charging voltage of the integration capacitor 119 attains to 2.5 volts, the second comparator element 86b activates and outputs a signal. The output signal of the comparator element 1 27b is amplified by an amplifier 128b. An output signal of the amplifier 1 27b is supplied to the thyristor 83b of the second quenching circuit H2 to fire the thyristor. By the conduction of the thyristor 83b, and thereby the second flash tube 19 of the second flash tube circuit F2 is extinguished.

The amplified output signal of the second amplifier element 1 27b of the amplifier circuit P is further supplied to the integration circuit L2 by way of the time delay circuit Q. In more detail, the output signal of the second amplifier 1 27b is supplied to the base electrode of the transistor 121 by way of the resistor 129 and the diode 131, and thereby the transistor 121 is made conductive after a time interval due to the time delay circuit Q. When the transistor 1 21 becomes conductive, the electric charge of the integration capacitor 11 9 of the integration circuit L2 is discharged through the collector-emitter path of the transistor 1 21 to reset the integrating operation of the integrator circuit L2.When the distance between the object to be photographed and the flash device is small, the integrating operation of the integration circuit L2 is adjusted by the resistor 120, and a part of the current to be supplied to the integration capacitor 11 9 is by-passed by the resistor 1 20.

It should be assumed that the first flash tube 1 7 flashes after the switch 69 is closed and ceases to flash after the predetermined time interval from the commencement of the flashing of the first flash tube 1 7. When the first flash tube 1 7 begins to flashing operation, the voltage generating circuit S produces the voltage, and the light receiving circuit L, receives the flash light reflected from the object to be photographed.In this case, the phototransistor 47 is made conductive in response to the reflected light quantity of reflecting light from the object to be photographed, the electric charge is stored on the integration capacitor 11 9. When the charging voltage of the integration capacitor 11 9 attains to the predetermined value V, such as 2 volts, the comparator circuit N activates in order to operate the first quenching circuit H, and the second trigger signal generating circuit E2.

By the signal supplied from the comparator element of the comparator circuit N, the first quenching circuit H, activates to stop the flash operation of the first flash tube 17, and, at the same time, the second trigger signal generating circuit E2 activates to start the flash operation of the second flash tube 1 9. By the flashing of the second flash tube 19, the charging voltage of the integration capacitor 11 9 further increases and attains to the predetermined value V2 such as 2.5 volts. When the charging voltage of the integration capacitor 11 9 attains to 2.5 volts, the second comparator element 1 27b activates in order to operate the second quenching circuit H2.

By the activation of the second quenching circuit H2, the flashing of the second flash tube 1 9 is stopped.

When the changeover switches 1 32 and 1 37 are switched to OFF states, the second trigger signal generating circuit E2 and the second quenching circuit H2 are rest to stopping the operations. Accordingly, the flashing operation first flash circuit F, only can be performed.

In accordance with the electric flash apparatus of Fig. 10, good flashing performance can be obtained, since the flash timing of the second flash tube 18 is adjusted by the light receiving circuit L1, the integration circuit L2, the reference voltage setting circuit M, the comparator circuit N and the time delay circuit 0. Further, it is convenient to use the electric flash apparatus as demands, since the flashing of the first flash tube 16 and the second flash tube 1 9 can be selected by changing over the first selector switch 1 32 and the second selector switch 1 37, which are actuated simultaneously.

As is apparent from the above description, the electric flash apparatus disclosed herein has the following advantages.

An advantages over the prior art is that the invention provides a new electric flash apparatus which can be made accurate in a distribution rate of the flash light quantity by providing respective main storage capacitor in each flash member.

Further advantage is that efficiency of the apparatus is improved, since a main storage capacitor is fully employed for flashing.

Furthermore, the apparatus can be used to perform bounce flash photography by setting a second casing at a desired angle with respect to a first casing, since the first casing and the second casing are rotatably connected together.

Fig. 11 shows the other embodiment of a control circuit arrangement of the invention.

The flash control circuit arrangement comprises a direct current power source circuit A, a converter circuit B for converting and boosting a direct current voltage from the direct current power source circuit A to an alternating current voltage, a rectifier circuit C for rectifying the alternating current voltage from the converter circuit B, an electric charge storing circuit D for supplying the electrical energy to the flash tubes 1 7 and 19, a trigger pulse generating means for triggering a flash tube circuit member, a switching circuit G for actuating the flash tube circuit member, a quenching circuit H for extinguishing the flash tube circuit member and a quenching trigger signal generating circuit I for actuating the quenching circuit H.The flash tube circuit member consists of the first flash tube 1 7 and the second flash tube 1 9. The trigger pulse generating means consists of a first trigger pulse generating circuit E, for triggering a first flash tube 1 7 and a second trigger pulse generating circuit E2 for triggering a second flash tube 19. The rectifier circuit C comprises a first rectifying element in the form of a first diode 63a of which an anode electrode is connected to a terminal of a secondary winding 61 b of an oscillating transformer 61 and a second rectifying element in the form of a second diode 63b of which a cathode is connected to a secondary winding 61 b.

The electric charge storing circuit D comprises a first main storage capacitor 64, a second main storage capacitor 65 and an indicating lamp 67, and is connected as shown. Capacity of the second main storage capacitor 65 is set to be greater than that of the first main storage capacitor 64, since the light quantity of the second flash tube 1 9 is greater than that of the first flash tube 1 7.

The quenching circuit H includes a quench tube 83 for quenching the flash tubes 1 7 and 19, a resistor 84, a commutation capacitor 85 and a resistor 87 and capacitors 87 and 88.

The quench tube 83 is connected to both electrodes of the second main storage capacitor 64 through the resistor 69. The commutation capacitor 85 is connected between a junction of the resistor 84 and the quench tube 83 and the anode electrode of the thyristor 78. A series circuit consisting of the resistor 87 and the capacitor 88 and is connected to the quench tube 47 in parallel relationship.

The quench trigger signal generating circuit I is provided with light sensing means for sensing the flash lights from the first and the second flash tubes 1 7 and 1 9 and flash light time duration adjusting means for adjusting maximum continuing time duration of the flash lights produced the first and the second flash tubes 17 and 19.

A circuit constructed in accordance with the foregoing description operates as follows.

When the power source switch 21 is closed, the voltage converter circuit B activates an oscillating operation, and thereby the high voltage is induced at the secondary winding 24b of the transformer 61. The boosted alternating current voltage is rectified by the rectifier circuit C, and thereafter electric charge is stored on the first main storage capacitor 28 and the second main storage capacitor 29. When the main storage capacitors 64 and 65 are fully charged up to the predetermined and suitable voltage, the neon glow lamp 67 lights indicating that the device is readiness for the flash tubes 1 7 and 1 9 to be fired. Simultaneously the triggering capacitors 71 and 76 are charged by the high DC voltage from the rectifier circuit C.In such conditions, the operation of the flash tube member is initiated by the closing of switch 69 of the second trigger pulse generating circuit E2 in synchronism with the camera shutter opening operation, enabling flash tubes 1 7 and 1 9. The stored voltage on the second main storage capacitor 65 appears across the electrodes 1 9a and 1 9b of the second flash tube 1 9. The triggering pulse generated from an output winding 77b is applied to the trigger electrode 1 9c of the second flash tube 19, and thereby a second flash tube 1 9 is triggered.And, at the same time, the first thyristor 74 of the first trigger pulse generating circuit E, is triggered and fired by a triggering signal from a detection winding 72c of the trigger transformer 36. By the firing of the first thyristor 74, the electric charge of a triggering capacitor 76 is discharged through the first thyristor 74 and an input winding 41a of the trigger transformer 77. The stored voltage on the first main storage capacitor 64 also appears across the electrodes 1 7a and 1 7b of the first flash tube 17.

The second flash tube 1 9 initiates a flash charge between the electrodes 1 9a and 19b, and, at the same time the first flash tube 1 7 also initiates a flash discharge between the electrodes 1 7a and 19b.

Under normal operation, the flash continues until the main storage capacitors 64 and 65 have discharged through the tubes 1 7 and 1 9 to the point where the voltage will no longer support the flash across the tubes 1 7 and 1 9.

That usually occurs after about several milliseconds.

The quench pulse generating circuit I senses the flash lights from the tubes 1 7 and 19, and automatically adjusts the maximum time duration of flash remains at that time determined by the discharge of the first and the second main capacitors 64 and 65 through the first and the second flash tubes 1 7 and 1 9. The quench pulse generating circuit I supplies a triggering pulse to a triggering electrode 83c of the quench tube 83.

That triggering pulse causes the quench tube 83 to become instantaneously conductive.

When the quench tube 83 becomes conductive, the first and the second flash tubes 1 7 and 1 9 are simultaneously and instantaneously extinguished.

In this case, the flash time durations of the first tube 1 7 and the second flash tube 1 9 are same and/or the approximately same, and the flash light quantity of the second flash tube 1 9 is greater than that of the first flash tube 17.

The electric flash device of Fig. 11 has the following advantages.

An advantage over the prior art flash apparatus is that the invention provides a new electric flash apparatus which the device can be made accurate in a distribution rate of the flash light quantity by providing respective main storage capacitor in each flash member.

Further advantage is that efficiency of the device is improved, since a first and a second main storage capacitors are fully employed for flashing.

Further the device can be used to perform bounce-flash photography by setting a second casing at a desired angle with respect to a first casing since the first casing and the second casing are rotatably connected together.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results are attained.

While a preferred embodiment of the invention has been shown and described, it will be apparent to those skilled in the art that modifications can be made without departing from the principle and spirit of the invention, the scope of which is defined in the appended claims. Accordingly, the foregoing embodiments are to be considered illustrative, rather than restricting of the invention and those modifications which come within the meaning and range of equivalency of the claims are to be included herein.

Claims (39)

1. An electric flash apparatus comprising first flashing means including a first flashing member having at least one flash tube and for generating a flash light directly toward an object to be photographed, a second flashing means including a second flashing member having at least one flash tube and for generating an indirect flash light with respect to said object to be photographed, and flash light controlling means for controlling said first flashing member and said second flashing member, wherein said flash light controlling means includes an electric charge storing circuit having at least one main storage capacitor for supplying electrical energy to said first and second flashing member, a trigger signal generating circuit said at least one first and at least one second flash tubes of said first and second flashing members, respectively, a flash tube circuit for generating a light flash and being connected to said at least one first flash tube and said at least one second flash tube, and a switching circuit for actuating said flash tube circuit, wherein said flash tube circuit includes flash light quantity control means for controlling the quantity of the light flash of said first and second flashing members so that the light flash quantity of said first flash tube is less than the light flash quantity of said second flash tube and flash timing control means responsive to the resultant total light flash light quantity of said at least one first and second flash tubes attaining a predetermined value for stopping flash of the at least one first flash tube and at least one second flash tube, said electric flash apparatus further comprising means for making illuminating area of the light flash from said first flashing member increase.

2. An electric flash apparatus as claimed in claim 1, wherein said means for making the illumination area of the light flash generated from the second flashing member increase comprises an illumination area increasing member including a light reflecting means for reflecting a flash light generated by said first flashing member.

3. An electric flash apparatus as claimed in claim 1, wherein said first flashing means comprises a first casing having said first flashing member, wherein said second flashing means comprises a second casing having said second flashing member, said light reflecting means comprises a reflecting plate for reflecting a flash light generated by said first flashing member.

4. An electric flash apparatus as claimed in claim 3, wherein said reflecting plate has wider reflecting area and, wherein said second flashing member is mounted on a first casing so as to be movable with respect to said reflecting plate.

5. An electric flash apparatus as claimed in claim 3, wherein said illumination increasing member is formed in said unit with a first casing of a flash housing.

6. An electric flash apparatus as claimed in claim 3, wherein said reflecting plate is mounted on a side edge portion of said first casing, and said second flashing member is pivotably connected to said second casing toward said reflecting plate.

7. An electric flash apparatus as claimed in claim 1, wherein said means for making an illumination area from said second flashing member increase comprises light diffusing means for diffusing a flash light from said second flashing member.

8. An electric flash apparatus as claimed in claim 1, wherein said first flashing means comprise a first casing having said first flashing member, wherein said second flashing means comprises a second casing having said second flashing member, and wherein said means for making an illumination area increase comprises a light diffusing member for diffusing a flash light generated by first flashing member.

9. An electric flash apparatus as claimed in claim 8, wherein said first flashing member provided on a side surface of said first casing so as to project toward outer side of the first casing and wherein said diffusing plate is mounted on said first casing so as to be opposed with respect to said first flashing member.

10. An electric flash apparatus as claimed in claim 8, wherein said light diffusing means comprises a diffusing plate provided on a front surface of said first casing.

11. An electric flash apparatus as claimed in claim 8, wherein said first casing is mounted on a top of a camera and includes a first flashing member having a diffusing plate, and wherein said second casing is mounted on said camera by a grip.

12. An electric flash apparatus as claimed in claim 1, wherein said electric charge storing circuit comprises a first main capacitor for supplying an electrical energy to said first flash tube and a second main storage capacitor for supplying an electric energy to said second flash tube.

1 3. An electric flash apparatus as claimed in claim 12, wherein a capacity of said second main storage capacitor is larger than a capacity of said first main storage capacitor.

14. An electric flash apparatus as claimed in claim 12, wherein said trigger signal generating circuit having means for supplying a trigger signal to said first flash tube and said second flash tube at an approximately same time.

1 5. An electric flash apparatus as claimed in claim 12, wherein said switching circuit including a switching element conjointly connected to said first flash tube and said second flash tube.

16. An electric flash apparatus as claimed in claim 12, further comprising a quenching circuit means for extinguishing said first and second flash tubes of the flash tube circuit member and a quench trigger signal generating circuit for actuating said quenching circuit and for supplying a quench triggering signal to the quenching circuit.

1 7. An electric flash apparatus as claimed in claim 14, wherein said trigger signal supplying means for supplying a trigger signal to said first and second flash tubes includes a trigger capacitor and a trigger transformer having an input winding connected to said trigger capacitor and an output winding electrically connected to trigger electrodes of said first and second flash tubes.

1 8. An electric flash device as claimed in claim 14, wherein said trigger signal supplying means comprises a first trigger circuit and a second trigger circuit, said first trigger circuit comprises a first trigger transformer having an input winding and an output winding connected to a trigger electrode of said first flash tube, a first trigger capacitor connected to said output winding and a switching element connected to said output winding of the first trigger transformer across the first trigger capacitor, and asecond trigger circuit comprises a second trigger transformer having an input winding, an output winding connected to a trigger electrode of said second flash tube and a detection winding for controlling said switching element of the first trigger circuit, a second trigger capacitor and a synchronous switch connected in parallel to said input winding of the second transformer across the second trigger capacitor.

1 9. An electric flash apparatus as claimed in claim 18, wherein said switching element is a first thyristor.

20. An electric flash apparatus as claimed in claim 12, wherein said flash timing control means includes an impedance element for making flash time durations of the first and the second flash tubes approximately same.

21. An electric apparatus as claimed in claim 20, wherein said impedance element is connected to said first flash tube in series relationship.

22. An electric flash apparatus as claimed in claim 21, wherein said impedance element is a resistor.

23. An electric flash apparatus as claimed in claim 21, wherein said impedance element is a coil.

24. An electric flash apparatus as claimed in claim 12, wherein said electric charge storing circuit further comprising an indicating lamp for indicating a charging condition of at least one of said main storage capacitors.

25. An electric flash apparatus as claimed in claim 12, wherein said electric charge storing circuit comprising a first main storage capacitor and a second main storage capacitor of which capacity is greater than that of said first main storage capacitor, and blocking means for blocking a current flowing from said first main storage capacitor to said second main storage capacitor.

26. An electric flash apparatus as claimed in claim 25, further including a rectifier circuit consisting of a diode connected to said first main storage capacitor by way of said blocking means and to said second main storage capacitor.

27. An electric flash apparatus as claimed in claim 14, wherein said second flash tube is set such that a flash light quantity is relatively large, and said first flash tube is set such that a flash light quantity is set to be smaller than that of said second flash tube.

28. An electric flash apparatus as claimed in claim 1, wherein said second flashing member is pivotably arranged with respect to said first flashing member.

29. An electric flash apparatus as claimed in claim 1, wherein said quenching circuit comprises a quench tube connected in parallel with a series circuit of said first and second flash tubes and second switching element of the switching circuit, and a commutation circuit for turning off said quench circuit.

30. An electric flash apparatus as claimed in claim 1, further comprising light detecting means for detecting flash light quantity of said flash light generated from at least one of said first and second flashing members by comparing an electric value obtained by integrating output of a light receiving circuit with a reference voltage.

31. An electric flash apparatus as claimed in claim 30, wherein said flash light quantity detecting means comprises a light receiving circuit including a light receiving element, an integration circuit for integrating a current of said light receiving circuit, a reference voltage setting circuit including a plurality of voltage dividing resistor, and a comparator circuit for receiving a plurality of reference voltage and charging voltage of an integration capacitor of said integration circuit.

32. An electric flash apparatus as claimed in claim 30 further comprising flashing operation controlling means for controlling flashing operation of at least one of said first flash tube of the first flashing member and said second flash tube of the second flashing member in response to output from said flash light quantity detecting means.

33. An electric flash apparatus as claimed in claim 30 further comprising a voltage generating circuit applying voltage to said light quantity detecting means.

34. An electric flash apparatus as claimed in claim 30 further comprising an integration resetting circuit for making the voltage of said integration circuit of said light quantity detecting means approximately zero after a predetermined time interval from a time point after flashing of said second flash tube.

35. An electric flash apparatus as claimed in claim 30, wherein said trigger signal generating means comprises a first trigger signal generating circuit for triggering said first flash tube, and a second trigger signal generating circuit for triggering said second flash tube, and said flash stopping means comprises a first quenching circuit for queching said first flash tube and a second quenching circuit for quenching said second flash tube.

36. An electric flash apparatus as claimed in claim 35 further comprising flashing operation controlling means for controlling operations of said first and second quenching circuits and said first and second trigger signal generating circuit.

37. An electric flash apparatus as claimed in claim 36, wherein said flashing operation controlling means having a first selector switch for selecting the operation of said second trigger signal generating circuit, and a second selector switch for selecting operation of said quenching circuit or operation of said second quenching circuit.

38. An electric flash apparatus substantially as hereinbefore described with reference to and as illustrated in Figs. 1 to 3 or any one of Figs. 4, 5, 6, 7 or 8 when taken in conjunction with Fig. 1.

39. An electric flash apparatus substantially as hereinbefore described with reference to and as illustrated in any one of Figs. 1, 4, 5, 6, 7 or 8 when taken in conjunction with any one of Figs. 9, 10 or 11.