| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a surface mounted piezoelectric part which is superior in reflow resistance and thermal shock resistance and can prevent a cap from coming off. SOLUTION: A piezoelectric element 10 is adhered/fixed to an insulating substrate 1. The electrode of the piezoelectric element 10 is connected to outer electrodes 2-4 formed on the insulating substrate 1. A metallic cap 40 covering the piezoelectric element 10 is adhered/sealed to the insulating substrate 1 with adhesive 41. Since the glass transfer temperature of a hardened object is less than or equal to 120 deg.C and the absolute value of the difference of the coefficient of thermal expansion between the cap 40 and the insulating substrate 1 is less than or equal to 8 ppm deg.C, adhesive power with respect to heat at the time of reflow soldering in adhesive 41 does not deteriorate and it can withstand against the rise in the internal pressure. Then, stresses on adhesive can be relieved, and the cap is surely prevented from coming off.</p> |
