Optical deflector including meander-type piezoelectric actuators and ill-balanced mirror structure

An optical deflector comprising:

• a mirror having first and second symmetrical axes;
• an outer frame surrounding said mirror;
• at least one meander-type piezoelectric actuator including a plurality of piezoelectric cantilevers in parallel with said second symmetrical axis folded at folded portions and coupled between said mirror and said outer frame,
• said mirror being divided by said first symmetrical axis into first and second half portions, said first half portion being close to a closest one of said folded portions and said second half portion being far from said closest folded portion,
• a mass of said second half portion being larger than a mass of said first half portion.

An optical deflector comprising:

• a mirror having first and second symmetrical axes;
• an inner frame surrounding said mirror;
• a pair of torsion bars coupled between said mirror and said inner frame;
• a pair of semi-ring shaped piezoelectric actuators coupled between said torsion bars and supported by said inner frame;
• at least one meander-type piezoelectric actuator including a plurality of piezoelectric cantilevers in parallel with said second symmetrical axis folded at folded portions and coupled between said inner frame and said outer frame,
• said inner frame being divided by said first symmetrical axis into first and second half portions, said first half portion being close to a closest one of said folded portions and said second half portion being far from said closest folded portion,
• a mass of said second half portion being larger than a mass of said first half portion.