Control system for terminating the discharge of a flash lamp

Claim 2

for operating said light measuring means. 3. The electronic flash arrangement .[.for photographic cameras.]. as defined in claim .[.2.]. .Iadd.14 .Iaddend.wherein the capacitance of said charging capacitor is

Claim 3

large compared to the capacitance of said ignition capacitor. 4. The electronic flash arrangement .[.for photographic cameras.]. as defined in claim 3 wherein the capacitance of said charging capacitor is ten times as

Claim 4

large as the capacitance of said ignition capacitor. 5. The electronic flash arrangement .[.for photographic cameras.]. as defined in claim .[.1.]. .Iadd.12 .Iaddend.wherein said light measuring means includes the series connection of a light sensitive element, an adjustable resistor,

Claim 5

and an integrating capacitor. 6. The electronic flash arrangement .[.for photographic cameras.]. as defined in claim 5 wherein said light sensitive

Claim 6

element is a photoresistor. 7. The electronic flash arrangement .[.for photographic cameras.]. as defined in claim 5 including controlled silicon rectifying means with cathode-control electrode path connected to said integrating capacitor means, discharge tube means .Iadd.connected in .Iaddend.parallel with said flash bulb means and ignited by said controlled rectifier means, the internal resistance of said discharge tube means being substantially smaller when ignited than the resistance of said

Claim 7

flash bulb means. 8. The electronic flash arrangement .[.for photographic cameras.]. as defined in claim 7 including protective resistor means between said integrating capacitor means and said .[.controlled.]..Iadd.control .Iaddend.electrode-cathode path of said

Claim 8

controlled rectifier means. 9. The electronic flash arrangement .[.for photographic cameras.]. as defined in claim 7 including an ignition transformer connected to said discharge tube means for igniting the same; ignition capacitor means connected between said ignition transformer means and said controlled rectifier means; and voltage divider means connected

Claim 9

to said ignition capacitor means and said controlled rectifier means. 10. The electronic flash arrangement .[.for photographic cameras.]. as defined in claim 9 including resistor means connected between said voltage divider means and the junction of said ignition capacitor means and said

Claim 10

controlled rectifier means. 11. The electronic flash arrangement .[.for photographic cameras.]. as defined in claim 10 wherein said resistor means has a resistance value .[.substantially of.]. .Iadd.in .Iaddend.the order of megohms. .Iadd. 12. An electronic flash arrangement for a photographic process, comprising in combination, flash generating means for generating a flash; ignition means connected to said flash generating means for igniting said flash generating means upon external activation, thereby initiating said flash, said external activation creating a current flow in said ignition means, said ignition means further comprising means for furnishing a D.C. voltage only after the start of said current flow; light measuring means operative only after application of an operating voltage thereto, for responding to light during an exposure and furnishing a terminating signal when said light has reached a predetermined light quantity; means connecting said ignition means to said light measuring means in such a manner that said D.C. voltage constitutes said operating voltage; and means connected to said light measuring means for terminating said flash upon receipt of said terminating signal. .Iaddend. .Iadd. 13. An electronic flash arrangement for a photographic process, comprising in combination, flash generating means for generating a flash; ignition means connected to said flash generating means for igniting said flash generating means upon external activation, thereby initiating said flash, said external activation creating a current flow in said ignition means, said ignition means further comprising means for creating a D.C. voltage only after the start of said current flow; light measuring means operative only after application of an operating voltage thereto, for responding to light during an exposure and furnishing a terminating signal when said light has reached a predetermined light quantity; means connecting said ignition means to said light measuring means in such a manner that said D.C. voltage constitutes said operating voltage; and means connected to said light measuring means for terminating said flash upon receipt of said terminating signal. .Iaddend. .Iadd. 14. An electronic flash arrangement for photographic process, comprising, in combination, flash generating means for generating a flash; ignition means connected to said flash generating means for igniting said flash generating means upon external activation, thereby initiating said flash, said ignition means comprising an ignition transformer connected to said flash generating means, an ignition capacitor connected to said ignition transformer and a charging capacitor connected to said ignition capacitor in response to said external activation in such a manner that a D.C. voltage is created across said charging capacitor resulting from discharge of said ignition capacitor; light measuring means operative only after application of an operating voltage thereto, for responding to light during an exposure and furnishing a terminating signal when said light has reached a predetermined light quantity; means for connecting said ignition means to said light measuring means in such a manner that said D.C. voltage across said charging capacitor constitutes said operating voltage; and means connected to said light measuring means and said flash generating means for terminating said flash upon receipt of said terminating signal..Iaddend.