Automatic control indication device in an automatic control type electronic flash unit

Abstract

In an automatic control type electronic flash unit having a light-sensing element for sensing reflection of light generated by an interior light discharge tube with the aid of charging current of a capacitor, light emission of the interior light discharge tube is automatically disconnected when the light-sensing element has sensed a predetermined quantity of light. The electronic flash unit includes means for indicating that light has been automatically controlled, first signal generating means for generating a first signal when the light-sensing element has sensed a predetermined quantity of light, and means for receiving the signal as input and for rendering the indicating means operative upon reception of the signal.

I claim:  .[.1. An automatic control type electronic flash unit which has a light-sensing element for sensing reflection of light generated by a flashlight discharge tube with the aid of charging current of a capacitor and which automatically discontinues light emission of the interior light discharge tube when the light-sensing element has sensed a predetermined quantity of light, said unit comprising: 
       means for indicating that light emitted by the flash unit has been automatically controlled; 
       first signal generating means for generating a first signal when said light-sensing element has sensed a predetermined quantity of light; and 
       means for receiving said signal as input and for rendering said indicating means operative upon reception of said signal..]. .[.2. An automatic control type electronic flash unit according to claim 1, further comprising second signal generating means for generating a second signal when said interior light discharge tube emits light, and wherein said means for receiving said signal is a bistable circuit which receives said first and said second signal as inputs and renders said indicating means operative upon reception of said first signal and renders said indicating means inoperative upon reception of said second signal..]. .[.3. An automatic control type electronic flash unit according to claim 1, further comprising a time constant circuit for controlling said indicating means so that said indicating means during its operative condition indicates by flashing that automatic control has been effected..].  .[.4. An automatic control type electronic flash unit according to claim 1, further comprising means for detecting the charging voltage of said capacitor and for deactivating said indicating means when said charging voltage has reached a value necessary to effect light emission of said interior light discharge tube..]. .[.5. An automatic control type electronic flash unit according to claim 1, wherein said indicating means is a discharge tube..]..Iadd. 6. An automatic control type electronic flash unit which has a light-sensing element for sensing reflection of light generated by a flashlight discharge tube with the aid of charging current of a capacitor and which automatically discontinues light emission of the flash light discharge tube when the light-sensing element has sensed a predetermined quantity of light, said unit comprising: 
       an indication element; 
       means for detecting a voltage of said capacitor; 
       first operative means for energizing said indicating element when said detecting means detects that said voltage has reached a predetermined value enough to ignite said flash discharge tube; 
       first signal generating means for generating a first signal when said light-sensing element has sensed a predetermined quantity of light; and 
       second operative means for receiving said first signal as input and energizing intermittently said indicating element after generation of flashlight of said flashlight discharge tube and before energization of said indicating element upon detection of said voltage. .Iaddend. .Iadd. 7. An automatic control type electronic flash unit according to claim 6, wherein said indicating element is a ready light provided in a camera. .Iaddend..Iadd. 8. An automatic control type electronic flash unit according to claim 6, wherein said indicating element includes a neon tube; and said second operative means includes a CR time constant circuit connected in parallel with said neon tube, and switching means actuated in response to said first signal to supply power to said neon tube and said CR time constant circuit. .Iaddend..Iadd. 9. An automatic control type electronic flash unit according to claim 8, further comprising a uni-directional semiconductive element through which a voltage divided from the voltage of said capacitor is applied to said neon tube. .Iaddend..Iadd. 10. An automatic control type electronic flash unit according to claim 9, wherein said first operative means further includes means for generating a second signal when said flashlight discharge tube emits light, and a bistable circuit which receives said first and said second signals as inputs and renders said switching means operative upon reception of said first signal and renders said switching means inoperative upon reception of said second signal. .Iaddend.