An exemplary liquid crystal display includes a liquid crystal panel having a plurality of pixel units arranged in rows, a scanning circuit configured to activate the pixel units row by row by outputting a plurality of corresponding scanning signals, a data circuit configured to provide data voltage signals to the activated pixel units, and a common voltage circuit. The control loop preferably includes the phase compensation calculation part for compensating the phase delay of the stopper opening position control signal for adjusting the amount of the molten metal to be fed to the mold. Since the head gimbal assembly is provided with a hole to receive the pivot therein provided with two straight edges, the relative positions of the turning axis of the pivot, the head gimbal assembly and the carriage assembly are adjusted properly so that clearances between the parts are absorbed.