| 摘要 |
PURPOSE:To obtain a high motor torque by forming electrodes of silver paste prepared by mixing two kinds of silver powder having particle size distributions of prescribed grain diameters with glass frit. CONSTITUTION:Electrodes 7a, 7b, 9a, and 9b are formed on a piezoelectric ceramic board by using silver paste prepared by mixing silver powder having a particle size distribution of grain diameters of 0.01-0.1mum and another kind of silver powder having a particle size distribution of grain diameters of 0.5-5mum. Since the silver powder having the particle size distribution of grain diameters of 0.01-0.1mum between each particle of the silver powder having the particle size distribution of the grain diameter of 0.55mum comes into contact with the ceramic board 5, no uneven contact occurs between the board 5 and electrodes. Especially, when the electrodes are formed of silver paste prepared by mixing silver powder having an average grain diameter of 5mum with the silver powder having an average grain diameter of 3mum at a weight ratio of 3:7, the mechanical strength and solderability of the electrodes are improved. Namely, a sufficiently strong electric field is impressed upon the piezo-electric ceramic board 5 and sufficient and accurate polarization alternately takes place in different directions. |
