A tip-tilt-piston piezoelectric micromirror with double-S shaped actuators based on sputtered PZT

To address the issues related to the structural constraints, thin-film stresses, and limited piezoelectric coefficients in tip-tilt-piston (TTP) piezoelectric micromirrors, a double-S-shaped piezoelectric actuator design is proposed to construct a TTP piezoelectric micromirror based on low-stress sputtered PZT thin film. A TTP piezoelectric micromirror with a 1 mm× 1 mm optical aperture has been designed, fabricated, and tested. The double-S piezoelectric actuator design enables large displacement. The sputtered PZT thin film exhibited relatively low stress of about 30 MPa. The maximum initial elevation of the double-S actuators was only about 10 μm. The maximum vertical displacement reached 41 μm at the frequency of 3.5 kHz. Under a driving voltage of 30 Vac at a resonant frequency of nearly 6.2 kHz, the tip and tilt optical scanning angles reach 16.2° and 15.6°, respectively. This high-frequency TTP micromirror, with a large optical aperture and scanning range, holds promise for various applications, especially in medical endoscopic imaging and optical phase modulation.