Characteristics and improved design of piezoresistive rotation angle sensor integrated in micromirror device

The characteristics and design of an improved piezoresistive rotation angle sensor integrated in a micromirror device are described. This study focuses on realizing higher resolution and accuracy in sensing the micromirror rotation angle compared with results reported in previous research. The structural design takes account of stress and temperature distributions. The lower resistance for current enables lock-in detection of rotation angle signals at a frequency higher than the mechanical resonant frequency of the micromirror, and the fluctuation generated by sensing the signal can be minimized. The resolved rotation angle is 0.02° and hysteresis of the signal is less than 4%.