Patent ID: 8729775

Claim:
A piezoelectric device, comprising: a piezoelectric vibrating piece that vibrates when electrically energized; a first package plate having first and second main surfaces, the first main surface defining a main recess having a bottom surface and being surrounded by a peripheral surface that is higher than the bottom surface, the piezoelectric vibrating piece being at least partially situated in the main recess; a second package plate aligned with the first package plate; a continuous band of adhesive extending peripherally around the main recess, the adhesive bonding the second package plate to the peripheral surface sufficiently for the first and second plates to define a cavity enclosing the piezoelectric vibrating piece; and a continuous band of metal film extending peripherally around the main recess inboard of the band of adhesive so as to be between the adhesive and the main recess to prevent flow of gas from the adhesive into the main recess; wherein the band of metal film comprises a horizontal metal-film portion and a contiguous vertical metal-film portion, the horizontal metal-film portion being parallel to the peripheral surface and the vertical metal-film portion extending longitudinally from the horizontal metal-film portion; the vertical metal-film portion is bonded to an inner wall of the main recess of the first package plate; and the band of adhesive extends onto the peripheral surface and contacts the vertical metal-film portion on the peripheral surface and also contacts the horizontal metal-film portion.