Two-dimensional comb-drive actuator and manufacturing method thereof

A two-dimensional comb-drive actuator, comprising:

• a supporting base having two sets of first comb electrodes;
• a frame connected to the supporting base and having two sets of internal comb electrodes and two sets of external comb electrodes, for rotating around a first rotational axis wherein the two sets of external comb electrodes are interdigitated to the two sets of first comb electrodes correspondingly;
• and
• a movable body connected to the frame and having two sets of second comb electrodes, for rotating around a second rotational axis which is perpendicular to the first rotational axis and interdigitated to the two sets of internal comb electrodes wherein along a specific direction perpendicular to the first and second rotational axes, a conducting layer is coated on a surface of at least one of the two sets of internal comb electrodes and the two sets of second comb electrodes, and on a surface of at least one of the two sets of first comb electrodes and the two sets of external comb electrodes, so that a comb electrode thickness of combing the conducting layer and at least one of the two sets of internal comb electrodes and the two sets of second comb electrodes is unequal to a thickness of each of the others of the two sets of internal comb electrodes and the two sets of second comb electrodes in the specific direction, and a comb electrode thickness of combing the conducting layer and at least one of the two sets of first comb electrodes and the two sets of external comb electrodes is unequal to a thickness of each of the others of the two sets of first comb electrodes and the two sets of external comb electrodes in the specific direction.