Method of direct bonding of crystals and crystal devices

摘要

A method of directly bonding a crystal to a crystal includes the steps of mirror-polishing the surfaces of the crystals and then rinsing them with a cleaning material and then affecting a baking operation and then bonding them together and thereafter annealing them within a temperature range where crystal crystallization is not transited in phase so that a further strong bonding force is obtained. A crystal resonator is obtained where electrodes are oppositely established across a ply crystal blank with at least two sheets of crystal blanks having a desired cut angle and a desired thickness being directly bonded so that the respective crystal axes intersect at the desired angles. The ply crystal blank may have a central portion which is either thicker or thinner than a surrounding portion. A crystal oscillator including a crystal resonator having the above noted features may be fabricated and a temperature compensated crystal oscillator of either the analog or digital type may also be formed using such a crystal resonator. A crystal filter may also be formed using a ply crystal bank with at least two sheets of crystal blanks having a desired cut angle and a desired shape being directly bonded so that respective crystal axes intersect at the desired angles.