A first counter electrode and a second counter electrode, for electrically coupling a first piezoelectric element unit and a second piezoelectric element unit, for composing a thin film piezoelectric element are common floating electrodes. The liquid crystal module comprises a liquid crystal panel, a backlight module and a back plate for assembling the liquid crystal panel and the backlight module together. Since this mirror angle adjustment mechanism requires only three parts, the case pivot, the mirror holder inner and the support pivot, the number of parts can be reduced and ease-of-assembly can be improved.