The central idea of the present invention is that a readout result of an optical detection unit which is based on accumulating photocharges can be improved when the charge carriers accumulated on a photodiode capacitance can be transferred to a readout capacitance before being read out by a readout unit, and when the state of the readout capacitance can be read out in a non-destructive manner by the readout unit, so that a noise portion in the readout signal can be corrected by reading out the readout capacitance during charge accumulation and again reading out the readout capacitance after the end of charge accumulation. Additionally, it becomes possible by the transfer to the readout capacitance to vary the sensitivity of the optical detection device within broad limits and to record a sequence of successive light pulses, without having to reset a photodiode before recording every single light pulse.