A crystal blank includes a vibrating arm which extends in a direction intersecting the polarization direction. In at least one of the upper surface and lower surface which are parallel to the direction of extension of the vibrating arm and run along polarization direction, the vibrating arm is provided with two recesses (grooves) in the width direction of the surface thereby having a pair of outer walls which are positioned on the two sides of the two recesses and a middle wall which is positioned between the two recesses. In the middle wall, the apex part is located at a position lower than the apex part of each of the pair of outer walls and is thinner than each of the pair of outer walls at the same heights.

To improve durability against impact, a quartz crystal resonator element includes a recess in a plan view. The quartz crystal resonator element further includes a first principal surface and a second principal surface that are front and rear surfaces facing away from each other and a side surface disposed between the first principal surface and the second principal surface, and the side surface is formed of flat surfaces and curved surfaces formed by dry etching and alternately arranged. The quartz crystal resonator element preferably has a base and at least one resonating arm extending from the base.

A tuning-fork type crystal resonator plate includes a base portion and a pair of leg portions protruding from the base portion in one direction. A groove and a bank portion are formed on at least one of main surfaces of each of the leg portions. The bank portion is formed accompanied by the formation of the groove, and a width of the bank portion differs along a width direction. The bank portion is constituted by a thick portion having a large width and a thin portion having a small width.

A tuning-fork type crystal resonator plate includes a base portion and a pair of leg portions protruding from the base portion in one direction. A groove and a bank portion are formed on at least one of main surfaces of each of the leg portions. The bank portion is formed accompanied by the formation of the groove, and a width of the bank portion differs along a width direction. The bank portion is constituted by a thick portion having a large width and a thin portion having a small width.

A vibrator (electronic device) includes: a vibrator element including vibrating arms; a base portion supporting the vibrator element and having a rectangular shape in a plan view; and a lid provided on the side of the vibrator element opposite to the base portion 3. Extending directions of long and short sides of the base portion and an extending direction of the vibrating arms cross each other. When an angle formed by the vibrating arms and a Y-axis direction is θ, the angle θ is more than 0° and less than 90°.

A vibrator (electronic device) includes: a vibrator element including vibrating arms; a base portion supporting the vibrator element and having a rectangular shape in a plan view; and a lid provided on the side of the vibrator element opposite to the base portion 3. Extending directions of long and short sides of the base portion and an extending direction of the vibrating arms cross each other. When an angle formed by the vibrating arms and a Y-axis direction is θ, the angle θ is more than 0° and less than 90°.

The piezoelectric vibrator element is miniaturized, and at the same time, the vibration leakage is suppressed. The piezoelectric vibrator element is formed so that the total length L1 of the piezoelectric vibrator element, the length L2 of the base, the width L3 of the connection part, the length L4 of the support arm part fulfill all of the following conditions A through C, Condition A: 0.1≦L2/L1≦0.2, Condition B: 0.4≦L3/L2≦0.6, Condition C: L4/L1≧0.7. While the miniaturization is realized by shortening the base due to the condition A, the distance via the base can be elongated due to the condition B. Further, by increasing the length of the support arm parts due to the condition C, it is possible to increase the total mass of the path transmitting the vibration to absorb the vibration to thereby further suppress the vibration leakage.

In the piezoelectric vibrator element, a larger area of the electrode part making a contribution to the vibration of the piezoelectric vibrator element is ensured. The piezoelectric vibrator element is a tuning-fork piezoelectric vibrator element, provided with a pair of vibrating arm parts extending from a base, and a groove part constant in width is formed on each of principal surfaces (reverse and obverse surfaces) in the longitudinal direction of the vibrating arm part. On the side surfaces and the principal surfaces, and in the groove part of the vibrating arm part, there are formed two systems of excitation electrodes. In the case of defining a width of a bank part formed by a side surface of the vibrating arm part and a side surface of the groove part as W0, and the distance between the excitation electrodes formed on the principal surface of the vibrating arm part as an electrode separation width W1, the electrode separation width W1 is formed in a range of 1 μm<W1<3 μm so as to fulfill W0>W1. By making the electrode separation width narrower than 3 μm, it is possible to increase the width of each of the excitation electrodes formed on the principal surface (on the bank part) of the vibrating arm part. Thus, the area of the electrode part making a contribution to the vibration can be increased, and the piezoelectric effect can be improved.

A tuning fork-type vibration piece is provided, in which a cushioning portion is formed on the base of a package to make contact with abutting portions of arm portions which are any parts but their edges, and the abutting portions of the arm portions allowed to contact the cushioning portion are electrodeless regions including no electrode, which prevents the risk of frequency fluctuations that may occur in case an electrode is chipped off by possible contact with the cushioning portion.

A tuning fork-type vibration piece is provided, in which a cushioning portion is formed on the base of a package to make contact with abutting portions of arm portions which are any parts but their edges, and the abutting portions of the arm portions allowed to contact the cushioning portion are electrodeless regions including no electrode, which prevents the risk of frequency fluctuations that may occur in case an electrode is chipped off by possible contact with the cushioning portion.