WO2002031975A1

WO2002031975A1 - Torsional vibrator

Info

Publication number: WO2002031975A1
Application number: PCT/JP2001/008588
Authority: WO
Inventors: Izumi Yamamoto; Tohru Yanagisawa; Hiromi Ueda
Original assignee: Citizen Watch Co., Ltd.
Priority date: 2000-10-10
Filing date: 2001-09-28
Publication date: 2002-04-18
Also published as: JP2002118441A

Abstract

A torsional vibrator comprising a base and three legs extending from the base, the torsional vibrations of two opposite-end legs out of the three legs being mutually in phase, the torsional vibration of one central leg and those of the two opposite-end legs being mutually in opposite phase. Each of the three legs has electrodes on respective surfaces, and electrodes on the facing surfaces of each leg are wired to keep them at the same potential; specifically, electrodes on the side surfaces of the one central leg and those on the front and rear surfaces of the two opposite-end legs are wired to keep them at the same potential, and electrodes on the front and rear surfaces of the one central and those on the side surfaces of the two opposite-end legs are wired to keep them at the same potential. A longitudinal length of an electrode is up to 0.5 time the entire length L of a leg extending from the leg base to the tip end thereof. The orientation of a quartz coincides with its direction set after the quartz is rotated on its X-axis through a rotation angle Υ, 25 ° ≤ Υ ≤ 45 °, while the width direction of the base is allowed to coincide with the X-axis of the quartz's crystal axes, and the longitudinal direction of a leg and its width direction are respectively allowed to agree with Y-axis and Z-axis of the quartz's crystal axes.

Description

Description Torsional vibrator Technical field

The present invention relates to a crystal oscillator used as a reference signal source for a timepiece or a mobile communication device. More specifically, the present invention relates to a torsional oscillator having a base and three legs extending therefrom, which is made of quartz. It concerns the shape of the child and the electrode structure on the surface of each leg. Background art

For example, a so-called tuning-fork type crystal unit having two vibrating legs is widely used as a reference signal source for watches and mobile communication devices. Such a two-leg tuning fork vibrator is used in a vibration mode (in-plane vibration) in which two legs bend and vibrate in directions opposite to each other in the plane, that is, in the plane.

FIG. 15 is a graph showing the temperature dependence of the resonance frequency of a conventional two-leg tuning fork resonator. Yo shown urchin, 2 resonant frequency f of Ashionsa oscillator, varies with the temperature T (horizontal axis), the percentage of change with respect to the maximum frequency f _Q (f one f.) Z f. (Vertical axis) indicates a quadratic curve that is convex upward as shown in the figure. In this case, the second-order temperature coefficient (coefficient β in the figure) with respect to temperature is about 3.5 × 10 " ² ppm / ° C ² .

FIG. 16 is a diagram showing the orientation of a conventional two-legged tuning fork vibrator. As already known, quartz is an anisotropic single crystal belonging to the trigonal system, and its properties differ depending on the angle at which the tuning fork is cut out. In a conventional two-leg tuning fork resonator, the width direction of the base 1 is defined as the X axis (electric axis) of the crystal axis of the crystal as shown in the figure, and the length direction and the thickness direction of the leg 3 are defined as the X axis. By setting the X axis as the axis of rotation from 0 to 5 ° from the state of being aligned with the Y axis (mechanical axis) and the Z axis (optical axis) of the crystal axis of the crystal, the temperature characteristics The peak of the quadratic curve (see Fig. 15) is near room temperature (around 25 ° C), and the quadratic temperature coefficient is also an optimum value.

By the way, since the change in the resonance frequency of the vibrator relates to, for example, the accuracy of the time display of a timepiece, various improvements in temperature characteristics have been conventionally proposed as described below. One of them is the use of a torsional vibration mode. For example, according to Japanese Patent Publication No. 58-29653 (piezoelectric resonator), the X-axis rotates 33 to 39 ° with the rotation axis as the rotation axis. It is shown that the torsional vibration of the quartz plate cut to the specified angle has little fluctuation due to the temperature change of the frequency and has good temperature characteristics.

The inventor of the present application conducted various experiments in consideration of applying such characteristics of the piezoelectric resonator to a two-leg tuning-fork type resonator. That is, in the structure of Fig. 16, the width direction of the base 1 is defined as the X axis of the crystal, and the longitudinal direction and the thickness direction of the leg 3 are defined as the Y axis (mechanical axis) and the Z axis (the crystal axis) of the crystal, respectively. (Optical axis), the direction was rotated by 30 ° to 35 ° with the X axis as the rotation axis. That is, the angle corresponding to “0 ° to 5 °” in FIG. 16 was set to “30 ° to 35 °”.

FIG. 17 is a diagram showing electrodes and wiring of a conventional two-leg tuning fork torsional vibrator, and is a diagram in which electrodes are arranged in the structure of FIG. In order to carry out the above experiment, electrodes were arranged on each surface of the legs as shown in FIG. 17 for the structure shown in FIG. 16, and the opposing electrodes were wired so as to have the same potential. In such an electrode structure, when observed by forced vibration from the outside using an impedance analyzer, torsional vibration with a resonance frequency near 260 kHz appears, and the secondary temperature coefficient is higher than that of a normal tuning fork. Was about one-third, and good temperature characteristics could be obtained. However, when this resonator is self-excited rather than forcedly vibrated from the outside, no torsional vibration occurs and the normal tuning fork vibration mode in which the two legs 3 perform primary bending vibration in the opposite direction to each other. The problem of oscillation caused by (in-plane primary vibration) has emerged. The cause is considered to be that oscillation is easy because the Q of the in-plane vibration is high and the equivalent series resistance is small. It has been found that this problem, that is, oscillation can be solved by, for example, inserting a frequency selection circuit in the oscillation circuit to suppress the signal in the frequency domain of the in-plane primary vibration, The introduction of the wave number selection circuit has a problem that the circuit configuration is complicated and the cost is increased.

FIG. 18 is a diagram showing other electrodes and wirings of a conventional two-leg tuning fork vibrator. As another example using the torsional vibration of a two-leg tuning fork, for example, in Japanese Patent Application Laid-Open No. Heisei 5-37285 (torsional quartz oscillator), the electrode 7 is not provided on the side of the leg as shown in the figure. Attempts have been made to excite torsional vibrations by providing two in parallel on each of the front and back surfaces. In this electrode structure, as described in this document, in a normal tuning fork shape in which two legs extend in parallel, excitation cannot be performed because the piezoelectric constant e _{16 used} is zero. Attempts to solve this problem have an angle at the base (spread at the base), but such a structure at the base of the leg is difficult to manufacture and is not practical.

Further, as another example utilizing the torsional vibration of a two-leg tuning fork, for example, Japanese Unexamined Patent Publication No. Hei. Similarly to Japanese Patent Publication No. 2885, there is shown an example in which electrodes are not provided on the side surfaces but two parallel electrodes 7 are provided on each of the front and back surfaces as shown in FIG. 18, but the piezoelectric constant e ₁₆ In order not to make zero, the width direction of the base 1 is set as the X axis of the crystal axis of the crystal, and the direction in which the legs extend and the thickness direction is matched with the Y axis and the Z axis, respectively, and the X axis is the rotation axis. Then In addition, it has been proposed to perform double rotation, in which a new thickness direction, the Z 'axis, is used as the rotation axis.

As mentioned above, various proposals have been made for torsional vibration. However, the problems to be solved can be summarized as follows: (1) The electrode structure shown in Fig. 17, that is, electrodes were formed on each surface of the legs 2 The leg tuning fork torsional vibrator had a problem that the circuit configuration was complicated, such as inserting a frequency selection circuit. (2) In the case of the electrode structure shown in Fig. 18, that is, a two-leg tuning fork torsional vibrator in which two parallel electrodes are provided on the front and back of the leg, the leg shape is complicated because the root of the leg has an angle, In addition, the rotation of the Z 'axis, which is a new thickness direction, is used as the rotation axis, so that the crystal plate is cut out twice, which makes the production extremely complicated and impractical. Disclosure of the invention

An object of the present invention is to solve the above-mentioned conventional problems, to simplify the circuit used for oscillation, to have a simple shape of the vibrator, to easily cut out a quartz plate, to manufacture easily and An object of the present invention is to provide a torsional vibrator having temperature characteristics.

To achieve the above object, the torsional vibrator of the present invention has one base and three legs extending in the same direction from the base, and each of the three legs is in a torsional vibration mode. It is characterized by being used in. The torsional vibrator of the present invention is preferably made of quartz.

In such a basic structure, in the torsional vibrator of the present invention, the torsional vibration of the two legs located at both ends of the three legs is in phase with each other, and the torsional vibration of one leg located at the center is provided. Is characterized by being in opposite phase to the torsional vibration of the two legs located at both ends.

Further, the torsional vibrator of the present invention has electrodes on each surface of the three legs, The electrodes are wired so that the electrodes on the opposing surfaces of the legs have the same potential. Specifically, the electrode on the side surface of one leg located at the center and the electrodes on the front and back surfaces of the two legs located at both ends have the same potential, and one electrode located at the center It is characterized in that the electrodes on the front and back surfaces of the legs and the electrodes on the side surfaces of the two legs located at both ends are wired so as to have the same potential.

Further, as a specific structure, the torsional vibrator of the present invention is characterized in that the length of the electrode in the longitudinal direction is 0.5 times or less of the total length L of the three legs from the root to the tip. I do.

Further, as a specific rotation angle, the torsional vibrator of the present invention uses the width direction of the base as the X axis (electrical axis) of the crystal axis of the crystal, and the longitudinal direction and the thickness direction of the legs, respectively. From the state that the Y axis (mechanical axis) and the Z axis (optical axis) of the crystal axis are aligned, the direction rotated by angle として with the X axis as the rotation axis, and angle 0 is the following inequality,

2 5 ° ≤ Θ ≤ 45 °

Is satisfied. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a view showing one embodiment of a torsional vibrator according to the present invention.

FIG. 3 is a diagram showing the orientation of quartz.

FIG. 2 is a graph showing the temperature dependence of the resonance frequency at the angle の of the torsional vibrator according to the present invention.

FIG. 3 is a graph showing how the angle 0 at which the apex temperature becomes room temperature changes depending on the side ratio in the torsional vibrator according to the present invention.

FIG. 4 is a diagram showing the electrode structure of the torsional vibrator according to the present invention.

FIG. 5 is a diagram showing electrodes and wirings of the torsional vibrator according to the present invention. FIG. 6 is an explanatory diagram illustrating an applied electric field of the torsional vibrator according to the present invention. You.

Figure 7 is a graph showing the variation of the piezoelectric constant of quartz with angle Θ. Figure 8 is a graph showing the angle Θ dependence of the etching rate of quartz.

Fig. 9 illustrates the movement of the legs of the torsional vibrator according to the present invention.

FIG. 10 is an explanatory diagram for explaining the movement of the leg due to the in-plane secondary vibration in the three-leg tuning fork.

FIG. 11 is a diagram showing an equivalent circuit of a crystal resonator.

FIG. 12 is a graph showing the relationship between the electrode length and the equivalent series resistance of the torsional vibrator according to the present invention.

Fig. 13 is an explanatory diagram for explaining the movement of the leg due to in-plane primary vibration in a three-leg tuning fork.

FIG. 14 is a circuit diagram showing an oscillation circuit for causing a torsional vibrator to self-oscillate according to the present invention.

Figure 15 is a graph showing the temperature dependence of the resonance frequency of a conventional two-leg tuning fork resonator.

FIG. 16 is a diagram showing the orientation of a conventional two-legged tuning fork vibrator.

FIG. 17 is a diagram showing electrodes and wiring of a conventional two-leg tuning fork torsional vibrator. FIG. 18 is a diagram showing other electrodes and wiring of a conventional two-leg tuning fork torsional vibrator. BEST MODE FOR CARRYING OUT THE INVENTION

In the three-leg tuning fork structure of the present invention, the mode in which each leg performs a primary bending vibration in the plane (primary vibration in the plane) is caused by an imbalance of the vibration energy as compared with the primary vibration in the plane of the two-leg tuning fork. Large leakage vibration to the base 1 It becomes. Therefore, if the torsional vibrator has a three-leg tuning fork structure, the leakage vibration will increase in this way, but the in-plane primary vibration will be less likely to oscillate by mounting on the circuit board. However, oscillation due to in-plane primary vibration does not occur. Therefore, in the three-leg tuning fork structure of the present invention, it is not necessary to add a special circuit such as a frequency selection circuit for suppressing oscillation.

Moreover, by taking the electrode structure of the electrodes facing each other provided with electrodes on each side of each leg at the same potential, it is possible to make the piezoelectric constant utilized as e _{'1 4} and e' _{3 6,} about the Z axis Since the piezoelectric constant to be used is not zero even when the rotation is zero, the three legs can have a simple structure that extends straight from the base. Furthermore, as described above, after rotating the X axis as the rotation axis, there is no need to perform double rotation such as further rotating the Z ′ axis as the rotation axis.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.

FIG. 1 is a view showing one embodiment of a torsional vibrator according to the present invention, and is an explanatory view for explaining the orientation of quartz. The torsional vibrator according to the present embodiment includes one base 1 and three legs 3 extending from the base 1 in the same direction.

The width direction of the torsional vibrator according to the present embodiment matches the X-axis direction of the crystal axis of quartz. The direction in which the legs extend and the thickness direction is 0 degrees with the X axis (electric axis) as the rotation axis from the state in which the Y axis (mechanical axis) and the Z axis (optical axis) of the crystal axis of the crystal are matched. Take in the direction just rotated. As shown, the longitudinal direction of the leg after rotation is the Y axis, and the thickness direction is the Z 'axis. Angle 0 is preferably in the range of 25 ° to 45 °. The range of this angle 0 was obtained as follows.

In other words, the crystal is a single crystal belonging to the trigonal system consisting of a S i O ₂ different Has anisotropy. The elastic constant depends on the direction and is expressed as a tensor. The temperature dependence differs for each component of the tensor. For this reason, the resonance frequency of a vibrator made of quartz varies depending on the direction with respect to the crystal axis, and the temperature dependence also changes with the direction.

FIG. 2 is a graph showing the temperature dependence of the resonance frequency at the angle 0 of the torsional vibrator according to the present invention. As explained in Fig. 15, the resonance frequency f changes with temperature (horizontal axis), and reaches the maximum frequency f. The ratio of the frequency change with respect to (f 1 f) / f _Q (vertical axis) is a quadratic curve that is convex upward. The secondary temperature coefficient of the torsional vibrator of the present invention is about 1.1 X 10 − a ² ppm / ° C ^2, the secondary temperature coefficient of a conventional 2 Ashionsa type flexural resonator explained in FIG. 5 (about -. 3 5 X 1 0 - 2 ppm / ° C 2) 3 minutes of It has a value of 1 or less and has good temperature characteristics. Here, the temperature indicating the maximum frequency f _Q is called the peak temperature. If the peak temperature 5 is near the middle of the operating temperature range, the width of the change in the resonance frequency becomes smaller, so it is necessary to select such an angle 0. The peak temperature 5 varies not only with the angle Θ but also with the ratio of the leg width W to the thickness D.

Figure 3 is a graph showing how the angle 0 at which the vertex temperature reaches 25 ° C changes depending on the side ratio WZD. A practical range in consideration of the balance of the strength and size of the oscillator is a side ratio W / D of 1 to 3. In this range, the angle 0 at which the peak temperature 5 becomes near room temperature is 25 ° to 45 °, and it is preferable that the side ratio WZD is 1 to 3.

Figure 8 is a graph showing the dependence of the etching rate of quartz on angle 0. The preferred value of the angle 0 according to the present invention is obtained for the following reasons. That is, the torsional vibrator of the present embodiment is manufactured by etching with a mixed solution of hydrofluoric acid and ammonium fluoride. Etching is water The etching rate varies as shown in the figure, depending on the crystal orientation, and also at an angle of 0. That is, the smaller the angle 0, the better the etching performance (etching rate). In the torsional vibrator of the present embodiment, the angle 0 is larger than that of the two-leg tuning fork vibrator used in the conventional bending vibration mode shown in FIG. 16, so that the etching time needs to be 3 to 4 times. Become.

Therefore, it is not preferable to increase the thickness D of the vibrator because mass productivity is impaired. In an actual design, it is only allowed to change the width W of the leg while keeping the thickness D substantially constant. When the thickness and the length of the legs are kept constant, reducing the side ratio W / D means that the leg width becomes smaller and the legs become thinner, so the smaller the side ratio W / D, the higher the resonance frequency. Become. However, when a torsional vibrator is used as a reference frequency source for a timepiece or a mobile communication device, it is not preferable because the power consumption increases when the frequency is high.

However, as shown in Fig. 3, if the side ratio WZD is large, it is necessary to increase the angle 0 at which the vertex temperature is near room temperature, but if the angle 0 is increased as shown in Fig. 8, the etching rate decreases. . As is clear from the above description, it is appropriate to set the side ratio WZD to around 2 in consideration of both the requirement from the resonance frequency and the requirement from the etching rate. Referring to FIG. 3, the angle 0 at which the side ratio is 1.5 to 2.5 and the vertex temperature is near room temperature is 30 ° to 40 °, which is a more preferable range at the angle 0. is there. As an example, when the thickness D = 100 μm, the leg width W = 186 μm, and the leg length Ι ^ = 2 375 μππ, the apex temperature becomes 0 at an angle of 0 = 34.6 °. It was 25 ° C. The frequency in this case was 262 kHz.

As described above, when determining the angle 0, it is necessary to consider the apex temperature and the etching properties, and as a result, 25 ° ≤ 0 ≤ 4 5 ° was determined to be suitable. A more preferable angle is 30 ° ≤ 0 ≤ 40. Was in the range.

FIG. 4 is a diagram showing an electrode structure of a torsional vibrator according to one embodiment of the present invention. Electrodes 7 (hatched portions) are provided on each surface of each leg 3. A frequency adjusting electrode 9 is provided at the tip of each leg 3. The resonance frequency is adjusted by changing the mass of the leg by trimming the frequency adjusting electrode 9 with a laser or the like.

FIG. 5 is a diagram showing electrodes and wirings of the torsional vibrator according to the present invention. As shown in the figure, electrodes 7 are arranged on the front and back surfaces and both side surfaces of three legs 3 shown in cross section, and each electrode is wired as shown. The electrode 7 is wired on each surface of the leg 3 so that the opposing electrodes have the same potential. The electrodes (a, b) on the sides of the center leg are at the same potential as the electrodes (g, h and k, 1) on the front and back surfaces of the legs located at both ends. The electrodes (c, d) on the back side are wired so as to have the same potential as the electrodes (e, f and i, j) on the side surfaces of the legs located at both ends.

FIG. 6 is an explanatory diagram showing an applied electric field of the torsional vibrator according to the present invention. The figure schematically shows an electric field 11 applied by the electrode 7 of the present embodiment. As shown, an electric field 11 is generated inside the leg 3 in the X and Z directions. The electric field 11 is point-symmetric with respect to the center of the cross section of the leg 3. The directions of the electric field 11 are opposite to each other with respect to the center in the X component and the Z ′ component.When the electric field component in the X direction is toward the center, the electric field component in the Z ′ direction is opposite to the center. Acts on

FIG. 7 is a graph showing the change in the piezoelectric constant of quartz with an angle of 0. The piezoelectric constant (vertical axis) utilized in torsional vibrator according to the present embodiment, e _'1 is ₄ and e, _{3 6.} The piezoelectric constants e and ₁₄ are constants that relate the electric field in the X direction to the shear strain (shear strain) in the Y, ₁₀₀ 'plane. The number e _'36 is a constant that relates Z, the direction of the electric field and X- Y, and shear strain in the plane.

When the angle 0 = 0, a piezoelectric constant e _'14 and e, ₃₆ corresponds to the e ₁₄ and e ₃₆ are quartz inherent piezoelectric constant, respectively (= 0). According to the electrode structure of the present embodiment, as shown in FIG. 6, an electric field that is point-symmetric with respect to the center of the leg cross section is generated in the X direction and the Z ′ direction, so that the piezoelectric transfer constants e, ₁₄ and e ′ ₃₆ It can oscillate torsional vibration. The values of the piezoelectric constants e ′ ₁₄ and e ′ ₃₆ change as shown in FIG. 7 depending on the angle 0, but within the preferable range of the angle 0 (that is, the range of 25 ° to 45 °). It can be seen that they have the same sign, can oscillate without contradiction, and are large enough to drive.

FIG. 9 is an explanatory diagram illustrating the movement of the legs of the torsional vibrator according to the present invention. As described above, the torsional vibrator of the present embodiment oscillates in another vibration mode ifi in which the center leg 3 and the legs 3 at both ends twist in opposite phases as shown in Fig. 9. I found that there was. The results of the experiment, the oscillation was found to be due to in-plane secondary vibration by the action of the piezoelectric constant e _12.

FIG. 10 is an explanatory diagram for explaining a leg motion due to in-plane secondary vibration in a three-leg tuning fork. The in-plane secondary vibration is a vibration in which the center of each leg expands (becomes a belly) as shown in the figure, and the center leg and the legs at both ends vibrate in opposite phases.

FIG. 11 is a diagram showing an equivalent circuit of a crystal resonator. Generally, the equivalent circuit of a crystal unit has an equivalent series inductance of 1 ^ and an equivalent series capacitance as shown in the figure. It can be represented by a circuit in which the equivalent parallel capacitance C _Q is added to the series circuit composed of the equivalent series resistance Ri. As a result of various experiments, it was found that changing the electrode length changed the equivalent series resistance of the in-plane secondary vibration, and shortening the electrode length increased the equivalent series resistance. this This is because the distortion of the in-plane secondary vibration is maximum near the center in the length direction of the leg and decreases toward the root (see Fig. 10). The inventor of the present application states that since the required distortion of torsional vibration is the maximum at the root of each leg, using the difference in distortion of in-plane secondary vibration depending on the location increases only the equivalent series resistance of in-plane secondary vibration. By doing so, we focused on the fact that oscillation can be made difficult. .

FIG. 12 is a graph showing the relationship between the electrode length and the equivalent series resistance of the torsional vibrator according to the present invention. This graph was obtained as a result of various experiments. As shown in the figure, while the equivalent series resistance of torsional vibration hardly changes with the electrode length and the Z-leg length (see the solid line), the in-plane secondary vibration Has a large change in equivalent series resistance (see dotted line). For example, when the electrode length and the total length of the z-leg are 0.5 times or less, the equivalent series resistance of the in-plane secondary vibration is preferably 10 times or more the equivalent series resistance of the torsional vibration. If the electrode length and the total length of the Z-leg are less than 0.4 times, the equivalent series resistance of the in-plane secondary vibration will be 20 times or more the equivalent series resistance of torsional vibration. Even if the equivalent series resistance of the vibration changes about twice, the equivalent series resistance of the in-plane secondary vibration becomes 10 times or more, and a sufficient margin can be obtained, which is more preferable.

Fig. 13 is an explanatory diagram for explaining the movement of the leg due to in-plane primary vibration in a three-leg tuning fork. In the torsional vibrator of the present embodiment, self-excited oscillation of in-plane primary vibration, which was a problem in the two-leg tuning fork, was not observed. In the measurement using an impedance analyzer, it was confirmed that the equivalent series resistance of the primary vibration in the plane where each leg performs bending primary vibration in the plane was 100 kΩ or more, and there was no danger of self-excited oscillation. This is because the in-plane primary vibration of the tripod tuning fork is accompanied by leakage vibration of the base 1. In the case of a two-legged tuning fork, the left and right legs 3 move in opposite directions, so that symmetry is good and the center line becomes a node, so that supporting the center of the base almost does not cause leakage vibration. As shown In addition, the in-plane primary vibration of a three-leg tuning fork has poor symmetry because the legs 3 at both ends and the center leg 3 bend and vibrate in opposite phases. For this reason, unless the widths of the legs 3 at both ends and the center leg 3 are changed, leakage vibration to the base 1 occurs. In a torsional vibrator, the resonance frequency is determined by the cross-sectional shape and length of the leg. Therefore, in a three-legged tuning fork torsional vibrator, each leg must have approximately the same cross-sectional shape, so that in-plane primary vibration involves leakage vibration.

FIG. 14 is a diagram showing an oscillation circuit for causing the torsional vibrator according to the present invention to self-oscillate. As described above, the torsional vibrator according to the present embodiment is based on the idea that unnecessary sub-vibrations are generated by modifying the characteristics of the vibrator itself (three-leg structure) and the electrode structure (electrode and _t electrode length and potential on each surface). The oscillation circuit can be easily realized by a simple circuit configuration in which the resistor 13 and the inverter 17 are connected in parallel to the oscillator 13 as shown in the figure. The equivalent series resistance of the torsional vibrator of this embodiment is about 1 to 5. The equivalent series resistance of a conventional torsional vibrator using parallel electrodes is about 30 to 50, which is about 1/10. The reason for this is that the provision of the electrodes on each side of the leg as in the present embodiment allows an electric field to be more effectively applied to the inside of the leg than to arrange the electrodes in parallel on a plane. Industrial applicability

As described above, the torsional vibrator of the present invention has good temperature characteristics, is simple in shape, is easy to cut out a quartz plate by a single rotation, is easy to manufacture, and has a simple oscillation circuit. This has the effect that the equivalent series resistance can be reduced, and a low power consumption torsional vibrator can be obtained. Therefore, it has extremely high industrial applicability as a reference signal source for clocks and mobile communication devices.

Claims

1. A torsional vibrator having one base and three legs extending from the base in the same direction, wherein each of the three legs is used in a torsional vibration mode.

2. The torsional vibrator according to claim 1, wherein two wires are located at both ends.

The torsional vibrations of the two legs located at the center are in phase with the torsional vibrations of the two legs located at both ends. Vibrator. of

3. The torsional vibrator according to claim 1 or 2, wherein the torsional vibrator is made of quartz.

4. The torsional vibrator according to claim 3, wherein each of the three legs has an electrode, and the electrodes on the opposing surfaces of each of the three legs have the same potential. A torsional vibrator characterized by being wired to.

5. The torsional vibrator according to claim 4, wherein the electrodes on the side surfaces of the one leg located at the center and the electrodes on the front and back surfaces of the two legs located at the both ends have the same potential. A torsional vibrator characterized in that the electrodes on the front and back surfaces of the one leg located at the center and the electrodes on the side surfaces of the two legs located at both ends are wired so as to have the same potential.

6. The torsional vibrator according to claim 4 or 5, wherein a length of the electrode in a longitudinal direction is 0.5 times a total length of the three legs from a root to a tip. A torsional vibrator characterized by the following.

7. The torsional vibrator according to any one of claims 3 to 6, wherein a width direction of the base is defined as an X axis of a crystal axis of the crystal, and a longitudinal direction and a thickness direction of the legs are respectively defined. From the state in which the crystal axis of the crystal is matched with the Y axis and Z axis, the direction rotated by angle 0 with the X axis as the rotation axis, and angle 0 is the following inequality 2 5 ° ≤ Θ ≤ 45 °

A torsional vibrator characterized by satisfying the following conditions.