FIG. 24A is a plan view showing the construction of the stator 2, and FIGS. 24B and 24C are cross sectional views along the lines B???B and A???A, respectively, shown in FIG. 24A. As shown in FIGS. 24A to 24C, the wirings connected to the stator electrodes 22A to 22C are electrically insulated from each other and extend to regions in the side portions of the substrate 11.