JPS6160611B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ultra-compact, high-performance thickness-shear crystal resonator.

Conventionally used thickness-shear crystal oscillators are mainly made of quartz, and electrodes 2 as shown in Figure 1 are used.
The main type of vibrator 1 is a disc type vibrator 1 having the following characteristics. Recently, a rectangular vibrator that is an improved version of the disk-shaped vibrator has been developed. For example, as shown in FIG. 2, a rectangular vibrator 1 has tapered inclined surfaces at both ends in the vibration direction.
is being developed. The former has the disadvantage of being very large because it is circular, and the latter has the disadvantage of being very large.
Even if the rectangular shape is made smaller, it is not only difficult to support it, but also vibrations other than the main vibration (hereinafter referred to as sub-vibrations) are generated due to the miniaturization, and there are drawbacks such as poor frequency-temperature characteristics. That is, by downsizing the vibrator and supporting the vibrator with a thin support wire, it is possible to minimize energy loss at the support point and obtain a high-performance vibrator. However, if a thin support wire is used, it will be weak against external shocks.
At the same time, since the secondary vibration has a close relationship with the external dimensions of the vibrator, considerable processing accuracy is required when determining the external dimensions by mechanical processing. Therefore, when using a thickness-shear oscillator as a time standard for a wristwatch, the dimensions are too large, and when attempting to downsize the oscillator, the characteristics deteriorate and support becomes difficult. Due to drawbacks such as easy generation of secondary vibrations, vulnerability to external shocks, and poor temperature characteristics, it cannot currently be used for wristwatches.

The present invention eliminates the above-mentioned drawbacks, and the thickness shear crystal resonator of the present invention will be explained below with reference to the drawings. Figures 3 and 4 show the cut-out angle of a conventional thickness-shear crystal resonator and its electric field direction, and when the X-axis, Y-axis, and Z-axis are respectively the electrical axis, mechanical axis, and optical axis. , when the clock is rotated θ ₁ rotation (θ ₁ ≒ 38°) with the X axis as the rotation axis, Y
When the new plate created by the plate is called Y' plate, the electric field (arrow) runs parallel to the Y' axis. In the case of this configuration, the above-mentioned drawbacks occur.

In the present invention, as shown in FIG. 5, when the electric, mechanical, and optical axes of the crystal axes of the water quenching oscillator are the X, Y, and Z axes, respectively, the Z plate is rotated with the Z axis as the rotation axis. 25 from an angle exceeding 0° opposite to the direction of rotation of the clock.
The new axis of the Z plate after rotating within the range below ゜
The excitation electrode is rotated by 30° to 45° on the Y′ axis and in the direction of clock rotation using the X′ axis as the rotational axis, and the excitation electrode is arranged on a plane perpendicular to the Y″ axis and the Z′ axis. 6
As shown in the figure, excitation electrodes are provided not only on the upper and lower surfaces but also on the side surfaces. Here, electrodes A ₁ , B ₁ , C ₁ are anodes,
By using A ₂ , B ₂ , and C ₂ as cathodes, a parallel electric field,
In other words, thickness-shear vibration can be caused by applying an electric field in the Y″-axis direction.Also, since the frequency of a thickness-shear oscillator is determined by the thickness in the Y″-axis direction, the above cut-out The thickness in the Y″ axis direction can be adjusted freely, and the frequency can be selected freely.

FIG. 7 shows an embodiment of the thickness-shear crystal resonator of the present invention, which is formed by integrally extending the support portions 3 from both ends of the crystal resonator 1 in the Y'' direction of the crystal resonator 1 shown in FIG. In this figure, A ₁ ,
A ₂ , B ₁ , B ₂ , C ₁ , and C ₂ represent electrodes. According to this embodiment, the support section 3 and the excitation section (crystal resonator) 1 can be integrally formed by etching, and defects such as secondary vibration can be eliminated.

As described above, according to the present invention, a resonator with excellent frequency-temperature characteristics can be obtained by selecting the cut angle, and in order to further increase the electric field efficiency, the direction of the crystal axis of the cut crystal resonator can be adjusted. By careful consideration, an optimal electrode structure can be obtained. In other words, the area of the plane perpendicular to the Z′ axis is larger than the other planes, and a pair of electrodes is provided on each of these planes, and the opposing electrodes are arranged so that they have the same polarity.
By arranging an electrode having the same polarity as an adjacent electrode on a plane perpendicular to the Y″ axis, the amount of electric field in the Y″ axis direction can be increased and the loss resistance of the vibrator can be reduced. Furthermore, if the vibrating part and the supporting part are integrally molded by etching, a highly accurate thickness shear crystal vibrator which is ultra-compact and free of secondary vibrations can be obtained, which is suitable for use in wristwatches.

The material for the crystal resonator includes quartz, lithium tantalate, lithium niobate, and the like.

[Brief explanation of the drawing]

Figure 1 is a plan view of a conventional disk-type thickness-shear crystal resonator, Figure 2 is a side view of a conventional rectangular thickness-shear crystal resonator, and Figures 3 and 4 are cut-outs of conventional thickness-shear crystal resonators. A diagram showing angles and their electric field directions.
FIG. 5 is a diagram showing the cutting angle of the thickness-shear crystal resonator of the present invention, FIG. 6 is a diagram showing the electric field direction of the thickness-shear crystal resonator of the present invention, and FIG. FIG. 1 is a plan view and a side view of a thickness-shear crystal resonator showing an example. 1...Crystal oscillator, 2...Support part.

Claims (1)

[Claims] 1 When the electric, mechanical, and optical axes of the crystal resonator are the X, Y, and Z axes, the Z plate should be rotated at an angle of more than 0° in the opposite direction of the clock's rotation with the Z axis as the rotation axis. After rotating the Z plate within a range of 25 degrees or less from the original angle, the Z plate is rotated 30 to 45 degrees in the clockwise direction using the X' axis as the rotation axis, and the Y ″axis and
In a thickness-shear crystal resonator in which excitation electrodes are arranged on a plane perpendicular to the Z' axis, the area of the plane perpendicular to the Z' axis is larger than the other planes, and a pair of electrodes are provided on each of these planes. A thickness-shear piezoelectric crystal resonator characterized in that the opposing electrodes are arranged so as to have the same polarity, and an electrode that has the same polarity as the adjacent electrode is arranged on a plane perpendicular to the Y″ axis.