A surface mount crystal unit comprising a crystal blank, a planar mounting substrate made of silicon and a cover having a shape with a recess and made of glass containing ions having high mobility. The mounting substrate and the cover are bonded by means of anode bonding and the crystal blank is hermetically...http://www.google.com/patents/US7034441?utm_source=gb-gplus-sharePatent US7034441 - Surface mount crystal unit and surface mount crystal oscillator
