Photodetection device and method

A photo-detecting device comprising:

• a photodetector for detecting incident light;
• an input J FET for reading out the sensing signal from the photodetector;
• an amplifier for amplifying the signal obtained by the input J FET;
• a feed-back circuit for feeding the output of the amplifier back to the gate of the input J FET through a feed-back capacitor;
• a reset circuit for resetting the feed-back capacitor;
• a reset pn-junction element in the reset circuit for discharging the feed-back capacitor to reset the capacitor;
• and
• a circuit of switch S2 and resistor;
• wherein the same voltage level as the gate voltage of the input J FET is applied to the anode (or cathode) of the reset pn-junction element through a resistor, a circuit of switch S2 and resistor is connected between the anode (or cathode) of the reset pn-junction element and the feed-back capacitor;
• and
• following turning the switch S2 “on”, the reset pn-junction element turns “on”.

A photo-detecting device comprising:

• a photodetector for detecting incident light;
• an input J FET for reading out the sensing signal from the photodetector;
• a reset pn-junction element for discharging the accumulated charge in the input J FET and/or the photodetector to reset the input J FET and/or the photodetector;
• a switch for turning the reset pn-junction element “on” or “off”;
• and a means for controlling the switch.

A photodetection device comprising:

• a photodetector for detecting incident light;
• a signal readout element for reading out the detection signal of the photodetector;
• an amplifier for amplifying the readout signal from the signal readout element;
• a feed-back circuit to feed the output of the amplifier back to the gate of the signal readout element through a feed-back capacitor;
• a reset circuit for resetting the feed-back capacitor;
• a first reset switch in the reset circuit for discharging the the feed-back capacitor to reset the capacitor;
• a second reset switch connected between the first reset switch and the feed-back capacitor, wherein the first reset switch is connected between the gate of the signal readout element and the output of the amplifier through the second reset switch.

A photo-detecting method for a photodetection device that comprises a photodetector for the detection of incident light;

• a signal readout element for reading out of the signal detected by the photodetector;
• an amplifier for amplifying the signal readout by the signal-readout element;
• a feed-back circuit for feeding the output of the amplifier back to the gate of the signal-readout element through a feed-back capacitor;
• a reset circuit for resetting the feed-back capacitor;
• a first switch in the reset circuit for discharging the feed-back capacitor;
• and a second reset switch connected between the first reset switch and the feed-back capacitor, wherein the first switch is connected between the gate of the signal readout element and the output of the amplifier via the second reset switch comprising that:
• the first reset switch and second reset switch are controlled so that the first reset switch is turned “on” and “off” while the second reset switch is “on”.

A photo-detecting method for a photodetection device that comprises a photodetector for the detection of incident light;

• a signal readout element for reading out of the signal detected by the photodetector;
• an amplifier for amplifying the signal readout by the signal-readout element;
• a feed-back circuit for feeding the output of the amplifier back to the gate of the signal-readout element through a feed-back capacitor;
• a reset circuit for resetting the feed-back capacitor;
• a first reset switch in the reset circuit for discharging the feed-back capacitor to reset the capacitor;
• and a second reset switch connected between the first reset switch and the feed-back capacitor, wherein the first switch is connected between the gate of the signal readout element and the output of the amplifier via the second reset switch comprising that:
• following turning the second switch to “on”, the first switch turns to “on”.