A liquid droplet manipulation system has a substrate with at least one electrode array and a central control unit for controlling selection of individual electrodes of the electrode array and for providing the electrodes with individual voltage pulses for manipulating liquid droplets by electrowetting. A working film is placed on top of the electrodes for manipulating samples in liquid droplets with the electrode array. At least one selected individual electrode of the electrode array is configured to be penetrated by light of an optical detection system for the optical inspection or analysis of samples in liquid droplets that are located on the working film. Also disclosed is working film that is to be placed on the electrode array and a cartridge that includes such a working film for manipulating samples in liquid droplets.