| 摘要 |
<p>1466958 Piezoelectric resonators MATSUSHITA ELECTRIC INDUSTRIAL CO Ltd 19 April 1974 [19 April 1973] 17360/74 Heading H1E A piezoelectric resonator using the energytrapping principle comprises a plate 10 of piezoelectric material having a restricted (resonant) area defined by electrodes 13, 14, 15 this area being thinner or thicker than the rest of the plate according to whether one of the following expressions is negative or positive, viz. for the thickness-extensional mode, and for the thickness-shear mode, where p and q are the members of the odd harmonic overtones and k=[2(1 - #)/(1 - 2#)]¢ where # is Poisson's ratio. Preferably a material having a Poisson's ratio less than one third is chosen, e.g. lead titanate ceramic with suitable additives.</p> |
