Patent ID: 8358053

Claim:
A unit comprising: a quartz crystal resonator vibratable in a flexural mode and having a base portion including a length less than 0.5 mm, and first and second vibrational arms connected to the base portion, each of the first and second vibrational arms having opposite main surfaces; wherein at least one groove is formed in each of two of the opposite main surfaces of each of the first and second vibrational arms; and wherein an electrode is disposed on a surface of the at least one groove formed in each of the two of the opposite main surfaces of each of the first and second vibrational arms so that the electrode disposed on the surface of the at least one groove formed in each of the two of the opposite main surfaces of the first vibrational arm has an electrical polarity opposite to an electrical polarity of the electrode disposed on the surface of the at least one groove formed in each of the two of the opposite main surfaces of the second vibrational arm.