| 摘要 |
PROBLEM TO BE SOLVED: To improve high-temperature characteristics of the piezoelectric element formed principally of lead zirconate titanate. SOLUTION: The specific resistance of a piezoelectric ceramic is decreased by one digit by incorporating cobalt oxide through the diffusion of the cobalt oxide in a baked piezoelectric ceramic sinter, formed principally of lead zirconate titanate from the surface through annealing, and consequently even if electric charges are generated due to pyroelectric operation due to temperature variation at reflow soldering or in in-use environment, the electric charges are diffused speedily by self-discharging because of a decrease in the resistance value. Consequently, polarization is not spoiled and variations of an antiresonance frequency fa and a resonance frequency fr can be suppressed. |
