Shutter timing apparatus

Claim 1

IN A CAMERA HAVING SHUTTER MEANS FOR CONTROLING EXPOSURE, THE COMBINATION OF; (A) SHUTTER OPERATOR MEANS IS CONSTRUCTED AND ARRANGED SO THAT SAID SHUTTER MEANS IS CAUSED TO INITIATE EXPOSURE IN RESPONSE TO ACTUATION OF SAID SHUTTER OPERATOR MEANS AND CAUSED TO TERMINATE EXPOSURE ONLY WHEN SAID SHUTTER OPERATOR MEANS IS DEATUATED FOR AT LEAST A GIVEN PERIOD OF TIME; (B) A VOLTAGE SENSITIVE TRIGGER CIRUCIT, INCLUDING A TRANSISTOR STAGE HAVING AN INPUT, FOR ACTUATING AND DEACTUATING SAID SHUTTER OPERATOR MEANS; (C) MEAN FOR CAUSING SAID VOLTAGE SENSITIVE TRIGGER CIRCUIT TO ACTUATE SAID SHUTTER OPERATOR MEANS; (D) AN ELECTRICAL NETWORK INCLUDING CAPACITOR MEANS COUPLED TO A PHOTORESPONSIVE ELEMENT THAT IIS EXPOSED TO LIGHT FROM A SCENE BEING PHOTOGRAPHED AND HAS A RESISTANCE INVERSELY RELATED TO THE LEVEL OF SCENE BRIGTHNESS; (E) MEANS COUPLING THE CAPACITOR MEANSN OF SAID NETWORK TO SAID INPUT; NF) SAID NETWORK BEING SO CONSTRUCTED AND ARRANGED THAT WHEN ACTIVATED, THE CHARGE ON SAID CAPACITOR MEANS BEGINS TO CHANGE CAUSING THE VOLTAGE AT SAID INPUT TO CHANGE FROM AN INITIAL VALUE, WHICH REVERSE BIASES SAID STAGE TO CUT-OFF, TO A PRESELECTED VALUE TERMED THE TRIGGER VOLTAGE, WHICH FORWARD BIEASES SASID STAGE INTO CONDUCTION, IN A PERIOD OFF TIME TERMED THE TRIGGER GENERATION TIME; (G) MEANS TO ACTIVATE SAID NETWORK SUBSTANTIALLY AT THE SAME TIME SAID VOLLTAGE SENNSITIVE TRIGGER CIRCUIT ACTUATES SAID SHUTTER OPERATOR MEAN; ANND NH) MEANS EFFECTIVE AT LOW LEVELS OF SCENE BRIGHTNESS FOR CAUSING SAID VOLTAGE SENSITIVE TRIGGER CIRCUIT TO DEACTUATE SAID SHUTTER OPERATOR MEAN FOR AT LEAST SAID GIVEN PERIOD OF TIME WHEN SAID STAGE IS FORWARD BIASED INTO CONDUCTION BY THE TRIGGER VOLTAGE, WHEREBY THE ACTUATION TIME OF SAID SHUTTER OPERATOR MEANS, AND CONSEQUENTLY THE EXPOSURE TIME, IS ESSENTRICALLY EQUAL TO THE TRIGGER GENNERATION TIME.