Patent attributes
A crystal device has an area defined inside a ceramic case thereof, and this area is made larger to increase the design freedom for mounting of a crystal unit (crystal element) in the crystal device. The crystal device is configured such that at least one crystal element is housed in a ceramic case in a rectangular form as seen in plan view. The crystal device includes the ceramic case having a bottom wall and a frame wall, and whose cross section is formed to be concave, and a metal cover jointed to a metal ring provided at an end face of the opening of the ceramic case by seam welding, to hermetically encapsulate the crystal element therein. The crystal device is configures such that one of the widths of the long side and the short side of the metal ring is shorter than the other one.
