The effects of metal depositions upon acceleration induced frequency shifts for quartz crystal units

摘要

A rigorous solution technique which may be used to accurately calculate quartz resonator frequency shifts arising from mechanical stresses is presented. This technique has been used to design a new mount, called the horizontal strip mount, to achieve low acceleration sensitivities for four-point SC-cut crystal units. Nine crystal units have been assembled with horizontal strip mounts for acceleration sensitivity testing. Acceleration sensitivities measured for the horizontal strip mount crystal units are much larger than predicted for the ideal crystal unit design. Efforts to reduce the acceleration sensitivities of the horizontal strip mount crystal units using off-center depositions of Au to alter mode shape and location were unsuccessful. Deposition histories are presented for additional four-point mount crystal units with different configurations and resonators similar to those mounted in the horizontal strip mounts. Iterative depositions of Au also had little effect on the acceleration sensitivities for these crystal units. Deposition histories are presented for asymmetric two-point mount crystal units. These crystal units responded to mode trimming and significant reductions in acceleration sensitivity were achieved.