| 摘要 |
PURPOSE:To be accessed at high speed when this actuator is used for an actuator for drive use of an optical pickup system by a method wherein electrodes formed on both the surface and the rear of a piezoelectric bimorph is set to a specific shape in order to prevent a high-order resonance oscillation mode other than a primary-order resonance oscillation mode from being generated. CONSTITUTION:One end of a piezoelectric bimorph 8 whose common electrode 9 has been sandwiched and held between piezoelectric materials 10 from both the surface and the rear surface is set as a fixed end A; a load mass 11 is attached to the side which has been set as a free end B on the other end. In such a bimorph-type piezoelectric actuator, a shape f(x) of electrodes 12 formed on both the surface and the rear of the piezoelectric bimorph 8 is set to a shape obtained after a linear normal function phi1(x) expressing a primary resonance oscillation mode of the piezoelectric bimorph 8 in a state having the load mass 11 has been second-order-differentiated as d<2>phi1(x)/dx<2> at a coordinate axis (x) in a longitudinal direction of the piezoelectric bimorph 8; the electrodes are formed symmetrically on both the surface and the rear of the piezoelectric bimorph 8. Thereby, it is possible to obtain the actuator, for optical pickup use, which can be accessed at high speed and which is small-sized and lightweight. |
