Imaging apparatus having high-frequency electron purging circuit operable during an exposure time

An imaging apparatus comprising:

• an image sensor having an array of successively arranged photoelectrical conversion areas isolated from each other by insulative regions, shift register means and a transfer gate having a barrier potential lower than a barrier potential of said insulative regions for transferring electrons developed in said conversion areas to said shift register means in response to a gate triggering pulse applied thereto;
• means for generating a triggering pulse;
• an optical unit for exposing said conversion areas to incident light for a time interval in response to said triggering pulse to cause said electrons to develop in said conversion areas;
• means responsive to said triggering device for generating high-frequency clock pulses and supplying the high-frequency clock pulses to said shift register means throughout said time interval to cause the shift register means to purge electrons transferred thereto from said conversion areas bypassing said transfer gate in the absence of said gate control signal;
• and
• means for generating low-frequency clock pulses immediately following the end of said exposure time and supplying the low-frequency clock pulses to said shift register means to cause it to discharge electrons transferred thereto from said conversion areas through said transfer gate to a utilization circuit.