Abstract: A crystal resonator comprises a first vibrating region provided on a crystal wafer, a second vibrating region provided on the crystal wafer, the second vibrating region having a different thickness and positive/negative orientation of the X-axis from those of the first vibrating region, and excitation electrodes which are provided respectively on the first vibrating region and the second vibrating region for causing the vibrating regions to vibrate independently. Frequencies that change by different amounts from each other relative to a temperature change can be retrieved from one vibrating region and the other vibrating region. Thus, based on an oscillating frequency of the vibrating region in which a clear frequency change occurs relative to the temperature, the oscillating frequency of the other vibrating region can be controlled. Thereby, increases in the complexity of the crystal oscillator can be suppressed.

Abstract: A crystal resonator comprises a first vibrating region provided on a crystal wafer, a second vibrating region provided on the crystal wafer, the second vibrating region having a different thickness and positive/negative orientation of the X-axis from those of the first vibrating region, and excitation electrodes which are provided respectively on the first vibrating region and the second vibrating region for causing the vibrating regions to vibrate independently. Frequencies that change by different amounts from each other relative to a temperature change can be retrieved from one vibrating region and the other vibrating region. Thus, based on an oscillating frequency of the vibrating region in which a clear frequency change occurs relative to the temperature, the oscillating frequency of the other vibrating region can be controlled. Thereby, increases in the complexity of the crystal oscillator can be suppressed.

Abstract: According to the invention, each detecting element pair of a wafer detector is constituted by light-emitting and light-receiving elements of transmission-type and is arranged at a position corresponding to a fitting edge portion of one of a plurality of wafers. The number of detecting element pairs is equal to the number of wafers which can be stored in the wafer counter. Light emitted from a light-emitting element to a light-receiving element is kept substantially perpendicular to a surface of a wafer and is shielded when a wafer is engaged in a wafer counter. A change in the amount of light received by the light-receiving element is detected by a signal processor electrically connected to each of the detecting element pairs. The positions and number of a large number of wafers can be accurately and instantaneously detected with an extremely simple structure.