| 摘要 |
PURPOSE:To reduce the crystal impedance to several 10OMEGA beyond the bounds of a conventional rectangular small-sized quartz oscillator, by forming flat faces having elliptic outlines on both principal surfaces of a quartz plate and decreasing the thickness of the quartz plate toward longer and shorter side. CONSTITUTION:An AT cut quartz plate is shaped to a rectangle, and flat faces 301 having elliptic outlines with a longer diameter l1 and a shorter diameter W1 are formed on both princial surfaces of a quartz plate 300 where the direction of longer sides, the direction of shorter sides, and the direction of the thickness of said AT cut quartz plate are used as the X axis, the Z' axis, and the Y' axis respectively. Between elliptic outlines of flat faces 301 and rectangular outlines of the quartz plate 300, a thickness t1 of the quartz plate 300 is decreased toward longer and shorter sides, and loci described by sets of points, which have the same thickness t1 on both principal surfaces are formed as similar ellipses 302, which are approximately similar to ellipses of flat faces 301, and parts 303 of them successively toward the peripheral part. Exciting electrodes 304 and leading-out electrodes 305 are arranged on both principal surfaces including flat faces 301, thus constituting a quartz oscillator. |
