Wireless multiflashlight apparatus for a photographic camera

Claim 2

In a wireless multiflashlight apparatus comprising: a main flashlight device including a first flash capacitor on which a predetermined voltage is precharged, and a first flash tube coupled substantially across said first flash capacitor to emit a first flashlight ray for illuminating a subject being photographed through the discharge of the voltage precharged on said first flash capacitor upon the shutter operation of the camera; and at least one additional flashlight device located in the neighborhood of the subject and away from said main flashlight device, said at least one additional flashlight device including a photoelectric conversion element operative to receive flashlight rays emitted from said first flash tube, an amplifier section coupled to said photoelectric conversion element, a switching element coupled to said amplifier section to be made operative by an output signal from said amplifier section, and a flashlight source which includes a second flash capacitor on which a predetermined voltage is precharged, and a second flash tube coupled to said switching element and to said second flash capacitor to emit a flashlight ray for illuminating the subject simultaneously with that from said first flash tube through the discharge of the voltage precharged on said second flash capacitor when a flashlight ray delivered from said first flash tube is received by said photoelectric conversion element and said switching element is made operative by an output signal from said photoelectric conversion element obtained through said amplifier section; the improvement wherein: said main flashlight device further comprises an additional flashlight generating means coupled to said first flash tube for generating at least a second flashlight ray from said first flash tube, with a predetermined time interval between said first and second flashlight rays, upon the shutter operation of the camera; and said additional flashlight device further comprises a decoder circuit coupled via said photoelectric conversion element between said amplifier section and said switching element for producing an output signal only responsive to at least two flashlight rays delivered from said main flashlight device being received by said photoelectric conversion element with said predetermined time interval therebetween, said output signal being coupled to said switching element for causing said switching element to become operative to cause a flashlight ray to be emitted from said second flash tube.

Claim 3

A wireless multiflashlight apparatus claimed in claim 1, wherein: said additional flashlight generating means included in said main flashlight device comprises a temporary flashlight interruption circuit comprising at least one series circuit connected across said first flash capacitor as well as said first flash tube, said series circuit including a parallel circuit of a capacitor and a resistor, and a further switching element which has a pair of main electrodes connected in series with said parallel circuit and a control electrode; and a timer circuit operatively coupled to the shutter of a camera and having an output terminal coupled with the control electrode of said further switching element and producing an output signal for causing said further switching element to be rendered operative a predetermined period of time after the operation of the shutter of the camera, thereby causing a discharge current flowing from said first flash capacitor into said first flash tube to be temporarily substantially reduced by charging said capacitor included in said parallel circuit therewith and subsequently to be substantially increased by rendering said further switching element inoperative at the completion of the charging operation of said capacitor of said parallel circuit; and said decoder circuit included in said additional flashlight device comprises a dc source having a positive terminal and a negative terminal; a first normally conductive transistor which has a base coupled via said amplifier section with said photoelectric conversion element, an emitter coupled with one of said positive and negative dc source terminals and a collector connected via a first resistor to the other dc source terminal, and which is rendered nonconductive through said amplifier section upon receipt of said at least first and second flashlight rays delivered from said main flashlight device by said photoelectric conversion element; a first capacitor which has one plate terminal connected to a junction of said first resistor with the collector of said first transistor and the other plate terminal connected via a second resistor to said one dc source terminal, and on which a voltage substantially equal to that of said dc source is charged when said first transistor is conductive; a second normally conductive transistor which has a base connected via a second capacitor to said one dc source terminal and also via a resistive element to a junction of said first capacitor with said second resistor, an emitter coupled with said one dc source terminal and a collector connected via a third resistor to the other dc source terminal, and which is rendered nonconductive, each time said first transistor is changed from a nonconductive state to a conductive state, as a function of the discharge of the voltage stored on said first capacitor obtained through the then conducting first transistor and said second capacitor; a first diode having a cathode connected to the collector of said first transistor and an anode connected to the collector of said second transistor; and a second diode having an anode connected to the collector of said second transistor and a cathode connected via at least one resistor to said one dc source terminal as well as coupled with the control electrode of said switching element included in said additional flashlight device, thereby permitting said switching element to be rendered operative only upon receipt of said at least first and second flashlight rays delivered from said main flashlight device by said photoelectric conversion element.

Claim 4

A wireless multiflashlight apparatus according to claim 1, wherein: said main flashlight device further includes a first switching element having a pair of main electrodes connected in series with those of said first flash tube and a control electrode coupled to said first flash capacitor and triggered through the discharge of the voltage precharged on said first flash capacitor upon operation of the shutter of the camera; said additional flashlight generating means included in said main flashlight device comprises a temperary flashlight interruption circuit comprising a second switching element having a pair of main electrodes coupled via a resistor substantially across said first flash capacitor and a control electrode; a timer circuit having an output terminal coupled with the control electrode of said second switching element and producing an output signal for causing said second switching element to be rendered operative a predetermined period of time after the shutter operation of the camera; and a capacitor on which a predetermined voltage is precharged and which is coupled between a junction of said second switching element with said resistor and a junction of said first switching element with said first flash tube firstly to discharge the capacitor at the triggering of said second switching element through the now conducting second switching element, said first flash capacitor, the now conducting first flash tube and first switching element, thereby causing said first switching element to be forcedly rendered inoperative temporarily, and subsequently to recharge the capacitor with a continuous discharge current obtained through the now conducting first flash tube from said first flash capacitor, thereby causing said first switching element to be again rendered operative; and said decoder circuit included in said additional flashlight device comprises a dc source having a positive terminal and a negative terminal; a first normally conductive transistor which has a base coupled via said amplifier section with said photoelectric conversion element, an emitter coupled with one of said positive and negative dc source terminals and a collector connected via a first resistor to the other dc source terminal; and which is rendered nonconductive through said amplifier section upon receipt of said at least first and second flashlight rays delivered from said main flashlight device by said photoelectric conversion element; a first capacitor which has one plate terminal connected to a junction of said first resistor with the collector of said first transistor and the other plate terminal connected via a second resistor with said one dc source terminal, and on which a voltage substantially equal to that of said dc source is charged when said first transistor is conductive; a second normally conductive transistor which has a base connected via a second capacitor to said one dc source terminal and also via a resistive element to a junction of said first capacitor with said second resistor, an emitter coupled with said one dc source terminal and a collector connected via a third resistor to the other dc source terminal, and which is rendered nonconductive, each time said first transistor is changed from a nonconductive state to a conductive state, as a function of the discharge of the voltage stored on said first capacitor obtained through the then conducting first transistor and said second capacitor; a first diode having a cathode connected to the collector of said first transistor and an anode connected to the collector of said second transistor; and a second diode having an anode connected to the collector of said second transistor and a cathode connected via at least one resistor to said one dc source terminal as well as coupled with the control electrode of said switching element included in said additional flashlight device, thereby permitting said swithcing element to be rendered operative only upon receipt of said at least first and second flashlight rays delivered from said main flashlight device by said photoelectric conversion element.

Claim 5

A wireless multiflashlight apparatus according to claim 1, wherein: said additional flashlight generating means included in said main flashlight device comprises at least one additional flash capacitor which has one plate terminal connected to one plate terminal of said first flash capacitor and the other plate terminal connected via a forwardly biased diode to the other plate terminal of said first flash capacitor, and on which a voltage substantially equal to that precharged on said first flash capacitor is precharged; a further switching element having a pair of main electrodes connected between the other plate terminal of said additional flash capacitor and the other plate terminal of said first flash capacitor and a control electrode; and a timer circuit having an ouput terminal coupled with the control electrode of said further switching element and producing an output signal for causing said further switching element to be rendered operative a predetermined period of time after operation of the shutter of the camera, thereby causing the voltage precharged on said additional flash capacitor to be discharged into said first flash tube; and said decoder circuit included in said additional flashlight device comprises a dc source having a positive terminal and a negative terminal; a first normally conductive transistor which has a base coupled via said amplifier section with said photoelectric conversion element, an emitter coupled with one of said positive and negative dc source terminals and a collector coupled via a first resistor with the other dc source terminal, and which is rendered nonconductive through said amplifier section upon receipt of said at least first and second flashlight rays delivered from said main flashlight device by said photoelectric conversion element; a second normally nonconductive transistor which has a base coupled via a second resistor with the collector of said first transistor and also via a first capacitor to said one dc source terminal, an emitter coupled with said one dc source terminal and a collector coupled via a third resistor with the other dc source terminal, and which is rendered conductive when a voltage charged on said first capacitor obtained through said first and second resistors from the other dc source terminal at the nonconduction of said first transistor reaches a predetermined level; a third normally conductive transistor which has a base coupled via a second capacitor with the collector of said second transistor, an emitter coupled with said one dc source terminal and a collector coupled via a fourth resistor with the other dc source terminal, and which is rendered nonconductive when said second transistor is changed from a nonconductive state to a conductive state; a fourth normally conductive transistor which has a base coupled via a third capacitor with the collector of said third transistor as well as via a fifth resistor with the other dc source terminal, an emitter coupled with said one dc source terminal and a collector coupled with the control electrode of said switching element included in said additional flashlight device as well as with the other dc source terminal via a sixth resistor, said third capacitor and said fourth and fifth resistors comprising a differentiation circuit which renders said fourth transistor nonconductive a predetermined period of time after said third transistor is changed from a nonconductive state to a conductive state; and a diode which is coupled between the collector of said first transistor and the collector of said fourth transistor, and which is rendered nonconductive to trigger said switching element, only when said first and fourth transistors are simultaneously in a nonconductive state.

Claim 6

A wireless multiflashlight apparatus according to claim 4, wherein said decoder circuit further includes a noise signal bypass means coupled between the collector of said first transistor and the base of said second transistor, said noise signal bypass means comprising a fourth capacitor connected between the collector of said first transistor and said one dc source terminal; a series circuit connected between the collector of said first transistor and the base of said second transistor and comprised of a fifth capacitor and a second diode with its anode-cathode path forwardly biased; and a seventh resistor connected between a junction of said fifth capacitor with said second diode and said one dc source terminal, and acting to bypass, where noise signals having a smaller level than a voltage level required to make said second transistor conductive are received and charged on said first capacitor connected between said second transistor base and said one dc source terminal.

Claim 7

A wireless multiflashlight apparatus according to claim 1, wherein said first flash tube has a pair of main electrodes, and wherein said main flashlight device further includes an inductor coupled between one plate of said first flash capacitor and one main electrode of said first flash tube to improve the rise time characteristic of a discharge current from said first flash capacitor to said first flash tube.

Claim 8

A wireless multiflashlight apparatus according to claim 1, wherein said main flashlight device further includes an indicator tube connected through a resistor across said first flash capacitor and lighted only when the voltage precharged on said first flash capacitor increases over a predetermined level.

Claim 9

A wireless multiflashlight apparatus according to claim 1 wherein said main flashlight device is mounted on a photographic camera, said at least one additional flashlight device being located remote from said camera.