A system for liquid droplet manipulation, the liquid droplet manipulation system comprising: at least one cartridge with an optically transparent polymer working film for manipulating samples in liquid droplets thereon; a substrate with at least one electrode array; and a central control unit for controlling the selection of individual electrodes of the electrode array(s) and for providing the electrodes with individual voltage pulses for manipulating liquid droplets by electrowetting, wherein the liquid droplet manipulation system is configured to receive on top of the electrodes the polymer working film for manipulating the samples in liquid droplets with the electrode array(s) when the polymer working film is placed on said electrode array(s), and wherein at least one selected individual electrode of the electrode array(s) of the liquid droplet manipulation system 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 polymer working film, wherein the at least one selected individual electrode is configured as an optically transparent electrode or as an optical via electrode that comprises a through hole, and the optically transparent electrode or the optical via electrode is located in place of an individual electrode in an electrode path or within a grid-like electrode array and is configured to be addressed by an electrode selection unit of the central control unit, wherein a) the optically transparent electrode is produced from ITO, or b) a spot of electrically connecting the optical via electrode with the electrode selection unit is located near a corner of the optical via electrode. at least one cartridge with an optically transparent polymer working film for manipulating samples in liquid droplets thereon; a substrate with at least one electrode array; and a central control unit for controlling the selection of individual electrodes of the electrode array(s) and for providing the electrodes with individual voltage pulses for manipulating liquid droplets by electrowetting, wherein the liquid droplet manipulation system is configured to receive on top of the electrodes the polymer working film for manipulating the samples in liquid droplets with the electrode array(s) when the polymer working film is placed on said electrode array(s), and wherein at least one selected individual electrode of the electrode array(s) of the liquid droplet manipulation system 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 polymer working film, wherein the at least one selected individual electrode is configured as an optically transparent electrode or as an optical via electrode that comprises a through hole, and the optically transparent electrode or the optical via electrode is located in place of an individual electrode in an electrode path or within a grid-like electrode array and is configured to be addressed by an electrode selection unit of the central control unit, wherein a) the optically transparent electrode is produced from ITO, or b) a spot of electrically connecting the optical via electrode with the electrode selection unit is located near a corner of the optical via electrode. a) the optically transparent electrode is produced from ITO, or b) a spot of electrically connecting the optical via electrode with the electrode selection unit is located near a corner of the optical via electrode.