Fluorescence lifetime sensor module and method of determining a fluorescence lifetime using a sensor module

A fluorescence lifetime sensor module comprising:

• an opaque housing having a first chamber and a second chamber separated by a light barrier,
• an optical emitter arranged in the first chamber, and configured to emit through a first aperture pulses of light of a specified wavelength arranged to optically excite a fluorescent probe positioned in front of the sensor module,
• a detector arranged in the second chamber, and configured to detect through a second aperture received photons from the fluorescent probe, wherein the received photons comprise:
• first photons corresponding to a reflection of at least some of the pulses of light by the fluorescent probe, and
• second photons corresponding to an a fluorescent emission by the fluorescent probe in response to an excitation of the florescent probe by the pulses of light,
• a measurement block comprising one or more time-to-digital converters, wherein the measurement block is configured to determine respective difference values representative of an arrival time of one of the received photons with respect to the emission pulses and,
• a histogram block comprising one or more memory cells, wherein the histogram block is configured to accumulate the difference values in a histogram,
• a processing circuit configured to operate in a time-of-flight mode of operation and in a measurement mode of operation,
• wherein in the time-of-flight mode of operation, the processing circuit is configured to:
• determine, based on the difference values, first time-of-flight values corresponding to the first photons, and
• determine, based on the first time-of-flight values, a distance between the sensor module and the fluorescent probe, and
• wherein in the measurement mode of operation, the processing circuit is configured to:
• compute second time-of-flight values for the second photons based on an evaluation of the histogram,
• compute a time offset value based on the determined distance between the sensor module and the fluorescent probe,
• compute a fluorescence lifetime based on the second time-of-flight values and the time offset value, and
• generate an output signal being indicative of the fluorescence lifetime of the fluorescent probe, and
• a control unit configured to initiate pulsed emission of the optical emitter.