Crystal Device and Method for Manufacturing Crystal Device

Abstract

An object of the present invention is to provide a crystal device that has stable vibration characteristics and that offers high reliability and high accuracy. The crystal device includes a first major face, which contains a portion of a base and a portion of a vibrating prong within a single plane, formed on the crystal plate, and a second major face, which contains another portion of the base and another portion of the vibrating prong within a single plane, formed on a crystal plate, wherein the first major face and the second major face have different outer shapes. The shapes of the first and second major faces can be produced by first forming mask layer patterns on a crystal substrate by exposure through different mask patterns and then etching the crystal substrate using the thus formed mask layer patterns.

Description

FIELD OF INVENTION [0001] The present invention relates to a crystal device comprising a base and a plurality of vibrating prongs protruding from the base, and a fabrication method for the same; more particularly, the invention relates to a tuning-fork type crystal gyro to be used as an angular velocity sensor, and a fabrication method for the same. BACKGROUND OF THE INVENTION [0002] With the widespread use of compact and high-accuracy products such as HDDs (Hard Disk Drives), mobile computers, portable telephones, car telephones, and other mobile communication apparatus in recent years, there has developed an increasing need to further enhance the reliability and accuracy of crystal devices, typically crystal oscillators, used in these products. [0003] The need for increased reliability and increased accuracy has been growing, among others, for crystal gyros used for angular velocity detection in navigation systems or for camera shake control in video cameras. [0004]FIG. 14 is a di...

AI Technical Summary

Benefits of technology

[0047] According to the crystal device of the present invention, the vibration of the (tuning-fork type) crystal plate can be stabilized, and as a result, a crystal device having high reliability and high accuracy can be achieved.

[0048] Further, according to the crystal device of the present invention, the processing step that has had to be performed after the etching step in the prior art in order to achieve stable vibration characteristics can be simplified or omitted, and as a result, productivity of the crystal device can be increased compared with the prior art.

[0049] Furthermore, when the crystal device of the present invention is used for a crystal gyro, the vibration can be stabilized, and therefore, the angular velocity can be detected accurately; as a result, a crystal gyro can be obtained that have high detection sensitivity and high accuracy.

[0050] According to the crystal device manufacturing method of the present invention, a crystal device having stable vibration characteristics can be formed, and as a result, a crystal device having high reliability and high accuracy can be produced.

[0051] Furthermore, according to the crystal device manufacturing method of the present invention, the processing step that has had to be performed after the etching step in the prior art in order to achieve stable vibration characteristics can be simplified or omitted, and as a result, productivity can be increased.

Problems solved by technology

In the case of a crystal gyro as one application example of the tuning-fork type crystal device, the vibration tilted toward the Z axis such as the vibration W1 shown in FIG. 14 becomes a very serious problem.

As a result, the prior art crystal gyro has had the problem of low accuracy and low reliability.

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