Spuriousless single wavelength quartz resonators

The primary research objective is to manufacture quartz resonators that can oscillate elastic waves with a single wavelength and a precise directional performance. This objective has been the dream of many researchers since the discovery of the piezoelectric effect of quartz in 1880 by the brothers Pierre and Jacques Curie who brought into being the development of the ultrasonic and electromagnetic oscillation of solid elastic vibration. The key for our success in resonating a single wavelength and directional high-frequency elastic wave in quartz crystal resonators is our discovery of the design method for simultaneously machining the convex surface and the concave rear surface in order to make a grooved concavo-convex lens shape by using the distortion phenomenon and dynamic pressure force. Furthermore, we propose that this design procedure enables the simultaneous shaping of central machining axes both for convex lens and concave lens. As the result, the two central axes become completely identical by themselves. Furthermore, we propose a design method for making those two axes and AT-cut main surfaces axes precisely identical. Based on these designs, novel quartz resonators, in which three axis lines perpendicular to the AT-cut primary surface are exactly overlapped, were developed successfully to be as the single-sided grooved-type in the two-step shape with an extremely small concavo-convex lens-shape. Furthermore. we started to develop the quartz resonator of two-step single sided grooved type in order to solve the anisotropy effect. Therefore, this quartz resonator could generate high frequency elastic waves such as 108.9 MHz, which had no spurious signal within 7 MHz near the primary one. We could oscillate the first directional high frequency wave with only primary signal.