Patent ID: 8581476

Claim:
A quartz-crystal device, comprising: a quartz-crystal piece comprising an excitation portion that vibrates whenever a voltage is impressed across the excitation portion, the vibration portion having a designated surface roughness; a package base fabricated of glass or quartz crystal having a crystal-lattice orientation, the package base having an inner main surface and an opposing outer main surface, the quartz crystal piece being mounted on the inner main surface; and a lid fabricated of glass or quartz crystal having a crystal-lattice orientation, the lid having an inner main surface and an outer main surface, the lid forming a package in which the quartz-crystal piece is sealed; wherein the package base and lid are made of either different respective materials or of the same material having different respective crystal-lattice orientations; wherein the inner main surface of the package base and inner main surface of the lid comprise respective bonding surfaces, the bonding surfaces having designated respective surface-roughnesses; and wherein respective main surface regions of the package base and lid, except for the respective bonding surfaces, have respective designated surface-roughnesses that are greater than the surface roughnesses of the bonding surfaces and greater than the surface-roughness of the excitation portion.