A power control method for polarity inversion in an LCD panel comprises the step of providing a storage capacitor on a circuit board. In one illustrative embodiment, the fluid delivery device may include an electro-osmotic pump having an anion exchange membrane and a cation exchange membrane in the same device. Sensors are stably attached, preferably via covalent or ionic bonds, to a surface within the device, such as the surface of the excitation source that is exposed to the sample. A thermal expansion coefficient of the second substrate can be configured to be substantially the same to a thermal expansion coefficient of the first substrate. With the first area G1, an unequivocal segmentation into independent market areas is defined and with this a world-wide unique locking system with enhanced security and applicability is created.