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 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 frequency adjustment method of a vibrator element includes preparing a vibrator element that has a vibrating arm, a first weight placed on one principal surface of the vibrating arm, and a second weight placed on the other principal surface of the vibrating arm, in which the first weight has a non-overlapping region which does not overlap the second weight in a plan view in a normal direction of the principal surface, preparing a substrate including a wiring portion, and fixing the vibrator element to the substrate by causing the other principal surface side of the vibrator element to face the substrate side, and irradiating the non-overlapping region of the first weight with an energy ray from one principal surface side, removing a portion of the non-overlapping region of the first weight, and adjusting a resonance frequency of the vibrating arm.

A frequency adjustment method of a vibrator element includes preparing a vibrator element that has a vibrating arm, a first weight placed on one principal surface of the vibrating arm, and a second weight placed on the other principal surface of the vibrating arm, in which the first weight has a non-overlapping region which does not overlap the second weight in a plan view in a normal direction of the principal surface, preparing a substrate including a wiring portion, and fixing the vibrator element to the substrate by causing the other principal surface side of the vibrator element to face the substrate side, and irradiating the non-overlapping region of the first weight with an energy ray from one principal surface side, removing a portion of the non-overlapping region of the first weight, and adjusting a resonance frequency of the vibrating arm.

A tuning-fork type quartz vibrator is disclosed that includes excitation electrodes and a tuning-fork type vibrating reed that is made of quartz and in which first and second vibrating arm sections are integrally joined to a base section. In each of the first and second vibrating sections, a plurality of through-holes and two or more crosspieces are provided. Further, an effective excitation electrode ratio is no more than 0.97, the effective excitation electrode ratio being expressed by (a total area of the excitation electrodes in a cross-section orthogonal to a second direction as a width direction of each of the first and second vibrating arm sections)/(an area of a region where the plurality of through-holes are provided in the cross-section orthogonal to the second direction as the width direction of each of the first and second vibrating arm sections).

A tuning-fork type quartz vibrator is disclosed that includes excitation electrodes and a tuning-fork type vibrating reed that is made of quartz and in which first and second vibrating arm sections are integrally joined to a base section. In each of the first and second vibrating sections, a plurality of through-holes and two or more crosspieces are provided. Further, an effective excitation electrode ratio is no more than 0.97, the effective excitation electrode ratio being expressed by (a total area of the excitation electrodes in a cross-section orthogonal to a second direction as a width direction of each of the first and second vibrating arm sections)/(an area of a region where the plurality of through-holes are provided in the cross-section orthogonal to the second direction as the width direction of each of the first and second vibrating arm sections).

A vibrator includes: a base portion; a vibrating arm including an arm portion which extends from the base portion, and a weight portion which is located on a tip end side of the arm portion and which has a first main surface and a second main surface that are in a front-back relationship; and a weight film disposed at the first main surface of the weight portion. The first main surface includes a first planar surface, a second planar surface which is located closer to the second main surface than is the first planar surface and which is parallel to the first planar surface, and an inclined surface which couples the first planar surface and the second planar surface and which forms an angle of 100° or less with the first planar surface. A method for manufacturing a vibrator includes: a preparation step of preparing the above-described vibrator; and a removing step of removing a part of the weight film by emitting an energy ray to the weight film from a normal direction of the first planar surface.

In a method for determining cleanliness of a cleaning member that contacts a substrate and with which scrub cleaning is performed, the method includes a first step of self-cleaning a cleaning member by releasing contaminants from the cleaning member into a cleaning liquid, and a second step of bringing a self-cleaning discharged liquid into contact with an electrode of a crystal oscillator, attaching the contaminants contained in the discharged liquid onto the electrode of the crystal oscillator, then measuring a frequency response of the crystal oscillator in which the contaminants are attached onto the electrode, and determining cleanliness of the cleaning member based on the measured frequency response.

In a method for determining cleanliness of a cleaning member that contacts a substrate and with which scrub cleaning is performed, the method includes a first step of self-cleaning a cleaning member by releasing contaminants from the cleaning member into a cleaning liquid, and a second step of bringing a self-cleaning discharged liquid into contact with an electrode of a crystal oscillator, attaching the contaminants contained in the discharged liquid onto the electrode of the crystal oscillator, then measuring a frequency response of the crystal oscillator in which the contaminants are attached onto the electrode, and determining cleanliness of the cleaning member based on the measured frequency response.