JPS6246083B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the cutting angle of torsional Alpo ₄ transducers.

The object of the invention is torsion Alpo ₄ oscillator frequency -
By theoretically analyzing the temperature characteristics, the frequency
Our goal is to provide a torsional Alpo ₄ resonator with excellent temperature characteristics.

In recent years, electronic wristwatches have become increasingly more accurate, and one example of this is the commercially available quartz wristwatch that uses a quartz crystal as a frequency standard. In the case of , the electromechanical coupling coefficient k is very small at about 10%, and furthermore, in the case of a warm-form bending resonator or a torsion crystal resonator, it becomes smaller when it is about 4%, and the frequency-capacitance characteristics can be sufficiently satisfied. It wasn't something. Therefore, the present invention focuses on the Alpo ₄ resonator, which has a larger electromechanical coupling coefficient than conventional crystal resonators.
In particular, by theoretically analyzing the frequency-temperature characteristics in the torsional vibration mode, we found a cut angle that has a zero temperature coefficient near room temperature.

The present invention will be explained below.

FIG. 1 shows a Y plate for explaining the present invention,
1 is an Alpo ₄ board.

Figure 2 shows the Y plate in Figure 1 with the X axis as the rotation axis.
The tuning-fork-shaped torsional Alpo ₄ oscillator 2 formed by the plate is shown when rotated .degree. And signal a,
b and c are the arm width of the tuning fork type torsion Alpo ₄ vibrator, respectively;
Thickness and arm length. Furthermore, its resonant frequency f
becomes as follows.

Therefore, when formula (1) is differentiated with respect to the temperature t to obtain the first-order temperature coefficient of the resonance frequency, the following form is obtained.

α=1/f ∂f/∂t =1/2(−S′ ₅₅ /S′ ₅₅ −ζ/ζ−I/I+
Q/Q)+S/S-C/C...(2) However, represents one-time differential of temperature t.

S' ₅₅ is the elastic compliance due to coordinate rotation ζ is the density of Alpo ₄ I=1+(b/a) ² S=b/a Q is a correction term and is a function of the elastic compliance S' ₅₅ S' ₆₆ .

By calculating equation (2) with respect to the angle θ and the side ratio (b/a), the cut angle at which the first-order temperature coefficient α=0 was found.

FIG. 3 shows the relationship between the primary temperature coefficient α and the cutting angle θ with respect to the side ratio (b/a) based on the theoretical calculation of the present invention. According to the main ring calculation, when the side ratio (b/a) = 0.1, at an angle of 33°, α = -17.2 × 10 ^-6 /°C, and as the angle θ increases, α gradually decreases, and the angle θ becomes Between 37° and 38°, α=0 and a zero temperature coefficient can be provided. If the angle θ is further increased, α becomes larger, and if the angle θ is further increased, the angle θ is 108° and α = +5.1×10 ^-6 /
℃, as the angle θ is increased, α gradually becomes smaller, and when the angle θ is between 111° and 112°, α=0, which can provide a zero temperature coefficient, and at the cut angle, the frequency - temperature The properties will be great. The above has been described for the case where side ratio (b/a) = 0.1, but according to this theoretical calculation, the same cut angle θ
(For example, in the range of 33° to 42°), as the side ratio (b/a) increases, α gradually becomes smaller. Further, when the cut angle θ (for example, in the range of 108° to 117°), α tends to gradually increase as the side ratio (b/a) increases. That is, according to the present theoretical calculation, it was found that the cut angle θ that gives a zero temperature coefficient has a close relationship with the side ratio (b/a) of the vibrator. In other words, when the side ratio (b/a) is changed from 0.01 to 1.5, the cut angle θ is from 33° to
It has been found that a temperature coefficient of zero can be obtained by selecting an angle of 42° or in the range of 108° to 117°.

Further, the reason why the side ratio (b/a) is set to 0.01 to 1.5 is that the loss resistance of the vibrator can be made as small as possible and the current consumption can be reduced.
In the present invention, when the side ratio (b/a) is set to 0.01 to 1.5, the cut angle at which α=0 is determined, making it possible to provide a torsion Alpo ₄ resonator with excellent frequency-temperature characteristics.

As described above, the present invention has found a cut angle having a zero temperature coefficient by theoretically analyzing the frequency-temperature characteristics of a torsion Alpo ₄ resonator.
This allows torsion with excellent frequency-temperature characteristics.
We were able to provide the Alpo ₄ oscillator. In the present invention, the tuning fork shape was described as an example, but normally,
Needless to say, the same can be said of rod-shaped objects used as torsional vibrators.

[Brief explanation of the drawing]

FIG. 1 shows a general view of a Y plate for explaining the present invention. FIG. 2 is a general view of a tuning fork type torsional vibrator formed from a plate formed by rotating the Y plate of FIG. 1 with the X axis as the rotation axis. FIG. 3 shows the relationship between the primary temperature coefficient α and the cutting angle θ with respect to the side ratio (b/a) based on the theoretical calculation of the present invention. 1...Alpo ₄ , c...Length of the tuning fork arm, b...Thickness of the tuning fork, a...Width of the warming fork arm.

Claims (1)

[Claims] 1 Torsion using Alpo ₄ In the Alpo ₄ resonator, if the X axis, Y axis, and Z axis are the electrical axis, mechanical axis, and optical axis of Alpo ₄ , respectively, then the Y plate is 33° to 42° with the X axis as the rotational axis. A torsional vibrator characterized by being cut out from a plate rotated by 108° or 117°.