Determination of photodetector elements used for measurement

A photodetector device comprising:

• a plurality of groups of photodetector elements that are consecutively arranged to each other within a particular region of a substrate, each of the photodetector elements being connected to a quench device and configured to generate an output signal corresponding to an intensity of light incident therein;
• a control circuit configured to:
• (a) electrically enable one of the groups of photodetector elements and electrically disable the other photodetector elements, and then (b) cause first measurement light to be emitted,
• (c) obtain an output signal from each of the photodetector elements of the enabled group when reflected first measurement light is incident on the photodetector device,
• repeat steps (a)-(c) for different groups of candidate photodetector elements until the output signal is obtained for all of the groups,
• acquire for each group of photodetector elements a value representative of the output signals from the photodetector elements of the group,
• select, based on the acquired values, one of the groups of photodetector elements that are arranged within the particular region of the substrate and to be energized for measurement of an object, and
• upon receipt of second measurement light reflected by the object at the energized photodetector elements, process output signals generated by the selected group of the photodetector elements;
• and
• an analog adding circuit connected to the photodetector elements and configured to output an analog signal corresponding to a total of the output signals from the photodetector elements of the enabled group.

A photodetector device comprising:

• a plurality of groups of photodetector elements that are consecutively arranged to each other within a particular region of a substrate, each of the photodetector elements being connected to a quench device and configured to generate an output signal corresponding to an intensity of light incident therein;
• a control circuit configured to:
• (a) electrically enable one of the groups of photodetector elements and electrically disable the other photodetector elements, and then (b) cause first measurement light to be emitted,
• (c) obtain an output signal from each of the photodetector elements of the enabled group when reflected first measurement light is incident on the photodetector device,
• repeat steps (a)-(c) for different groups of candidate photodetector elements until the output signal is obtained for all of the groups,
• acquire for each group of photodetector elements a value representative of the output signals from the photodetector elements of the group,
• select, based on the acquired values, one of the groups of photodetector elements that are arranged within the particular region of the substrate and to be energized for measurement of an object, and
• upon receipt of second measurement light reflected by the object at the energized photodetector elements, process output signals generated by the selected group of the photodetector elements;
• a flip-flop circuit connected to each of the photodetector elements to receive the output signal therefrom;
• and
• a digital adding circuit connected to the flip-flop circuit, and configured to output a digital signal corresponding to a total of the output signals from the flip-flop circuits.