JPH02132914A - Electrode structure of vertical crystal resonator - Google Patents

Abstract

PURPOSE:To easily cause tertiary higher harmonic wave vibration, and to obtain higher frequency by dividing an exciting electrode arranged on a vibrating part into three parts, and impressing heteropolar voltage upon the neighboring electrodes. CONSTITUTION:The tertiary higher harmonic wave vibration is represented by displacement to expand outward and the displacement to contract inward. Therefore, the exciting electrode is arranged so that the displacement shown by arrow marks A, B is caused. As shown in a figure, the exciting electrodes 9, 10 are constituted so that they are heteropolar, and in addition, are divided into three parts by a vibrating part 2, and the neighboring electrodes are impressed by the heteropolar voltage. Thus, the tertiary higher harmonic wave vibration can easily be caused, and the higher frequency can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vertical crystal resonator whose frequency covers a medium frequency band after 3 MHz. In particular, the shape of the oscillator and the arrangement of the transducer electrodes are concerned. [Summary of the Invention] An object of the present invention is to provide a compact vertical crystal resonator with very little vibration leakage and a small R. Crystals are physical,
It is also a very chemically stable substance, and therefore, so-called crystal resonators formed from it can have low loss resistance and a high Q value. However, such excellent characteristics can only be obtained by designing a vibrator shape with minimal vibration leakage. In the present invention, the shape of the supporting part of a vertical quartz crystal resonator in which the vibrating part and the supporting part are integrally formed by an etching method is devised and improved, and by inducing higher-order vibration, the energy of the higher-order vibration is reduced. It can be confined inside the vibrating part. As a result, a vertical crystal resonator with a small loss resistance R and a high Q value can be obtained even at high frequencies. For this purpose, the present invention provides a loss resistance R
The purpose of this invention is to provide a vibrating electrode with good field efficiency and a small field efficiency. [Conventional technique {E 11] In a conventional vertical crystal resonator in which the vibrating part and the support part are integrally formed by etching, the width of the frame of the support part is uniform;
Moreover, since they are formed in the same direction and mounted at their ends, the energy of the vibrating part is transmitted to the mount part, causing vibration leakage. Therefore, the loss resistance R1
It was not possible to obtain a small vertical crystal oscillator. At the same time, R1 at the third harmonic vibration could not be reduced for the reasons mentioned above. [Problem to be Solved by the Invention 1] To address this issue, attempts have been made to increase the amplifier's amplification degree, but this has drawbacks such as increased current consumption, and in severe cases, vibrations may occur when placed in equipment. The problem was that the leakage was large and the oscillation stopped. Therefore, the present invention proposes a vertical crystal resonator with extremely small vibration leakage. In other words, it provides a shape with very little vibration leakage. At the same time, the objective is to provide an excitation electrode with low vibration leakage and high excitation efficiency. [Means for Solving the Problems] FIGS. 1(a) and (b) show an embodiment of the vertical crystal oscillator according to the present invention in plan view, and FIG. 2 shows the principle of the vertical quartz crystal oscillator shown in FIG. 1. This is a simplified plan view for explaining. In FIG. 2, the vibrator 1 consists of a vibrating part 2 and a support part 3, and the support part 3 can be considered to be fixed under the boundary condition of being supported at both ends. Also, the vibrating part 2 is expressed by length Ll, width W1, and thickness T, and the support part 3 is expressed by length L2 and width W2.
Now, when the vibrating part 2 of the vibrator l undergoes an elongated displacement as shown by the arrow A, the part 11 of the vibrating part 2 is displaced in the direction of the arrow of the support part 3 as shown by the arrow B. It vibrates.
In other words, it vibrates in the third harmonic mode. Therefore, at this time, the bent portion of the support portion 3 naturally generates a bending mode outward as shown by arrow C. Here, the part where the bending mode occurs is shown as bending part 5. Conversely, if the vibrating part 2 contracts, the supporting part 3
The door bending portion 5 generates a bending mode inwardly. That is, in the present invention, by converting the displacement of the vibrating part 2 in the width direction into the bending mode of the support part 3, the degree of freedom of vibration is not suppressed. In reality, there are dimensions that do not suppress vibration. The shape and dimensions are determined by the strain energy of the vibrating section 2. That is, the strain energy of the vibrating part 2 is set to Ul. The strain energy at the bending part is U
2, then U, . U. is expressed by the following equation.

However, stress T2, strain S2, Young's modulus E. Second moment of area I, displacement V, body weight V+. V2. zatM x
is shown. Furthermore, from equations (1) and (2), a modified relationship holds true that does not suppress the vibration of the vertical crystal oscillator.

Ul > U2 (3) From this, the bent portion 50 dimension L. ．． W2 is determined. For example, the fundamental oscillation frequency of the third harmonic of the present invention (1M several IMHz
The dimensions of the vibrating part in this case are the length L. =2.6mm. W+
=80μm. When T=160 am, the dimensional ratio W 2 / L 2 of the bent portion of the support portion should be 0.16 or less.
By determining the dimensions in this way, it is possible to obtain a vertical crystal resonator with low loss resistance and a high Q value. Next, we will discuss vibration leakage. As can be seen from the simplified diagram in FIG. 2, the vibration energy of the vibrating part 2 is transmitted to the support part 3 via the bridge part 4. Therefore, it is sufficient to reduce the energy loss in the support part 3, and since the mode of the support part 3 is converted to a bending mode, if the masses of the support parts at both ends are substantially infinitely large, The energy of the bent portion 5 will not leak up to the mount portion 8. In other words, the present invention has a shape that converts the bending mode of the support part 3 which is also transmitted to the vibrating part 2, that is, the ratio W2 of the width W2 and the length L2. /L. By selecting , the object of the present invention is achieved by freeing the vibration of the vibrating part and infinitely increasing the mass of the supporting part that has the boundary condition of support at both ends connected to the part in the bending mode. It is.

[Function] As described above, the present invention is composed of a vibrating section and a supporting section.
By improving the shape and dimensions of the support part of the vertical crystal resonator formed by the etching method, the loss resistance is reduced.
Moreover, a vertical crystal resonator having a high Q value can be obtained. At the same time, by analyzing the vibration mode of the support part, a vertical crystal resonator with small vibration leakage can be obtained. Furthermore, by devising and improving the excitation electrode arrangement, it is possible to easily generate third-order harmonic vibration and obtain higher frequencies. [Example] Next, the results obtained in the present invention will be specifically described. 1st
Figures (a) and (b) show an embodiment of the vertical crystal resonator of the present invention, with Figure 1 (a) being a front view and Figure 1 (b) being a bottom view. Vibrator I It vibrating part 2 and support part 3 to bridge part 4
It is constructed through an etching method and is integrally formed. The support part 3 is made up of a bent part 5, a hole 7, a frame 6, and a mount part 8. The vibrating part 2 is driven by an external electric field, that is, by the excitation electrodes 9 and 1O, and expands and contracts in the longitudinal direction, but at the same time, in the vertical direction,
That is, similar vibrations occur in the direction of the bridge portion 4 as well. At this time, first of all, in order to freely excite vibrations in the longitudinal direction of the vibrating part 2, it is important to make the vibrations in the direction of the bridge part 4 sufficiently free. A hole 7 is provided so that the part 5 can vibrate sufficiently freely. Also, depending on the ratio of the length and width W (not shown) of the bent portion 5, for example, when the frequency is about 3 MHz,
If the side ratio W/L is 0.16 or less, the 1 m pressure of vibration in the longitudinal direction can be sufficiently reduced. Next, regarding vibration leakage, the vibrator l is integrally formed from the vibrating part 2 to the bending part 5 via the bridge part 4 by an etching method. 7
is provided. Further, both ends of the hole are connected to the frame 6 and extend to the mount section 8. Therefore, the vibration of the vibrating part 2 in the direction of the bridge part 4 is converted into a bending mode, and is connected to the frame 6 through both ends of the hole 7 and extends to the mount part, so it can be fixed by the mount part 8. However, a vertical crystal resonator with no vibration leakage can be obtained. Next, a method for exciting third-order harmonics, which is a feature of the present invention, will be described.

As shown in FIG. 2, the third harmonic vibration is represented by a displacement extending outward and a displacement contracting inward. Therefore, arrow A. The excitation electrodes should be arranged so that the displacement shown in B occurs. From this, Fig. 1(a). As shown in (b), the excitation electrodes 9 and 10 can be purchased as different electrodes, divided into three by the vibration 2, and the voltage of the different electrodes 1 applied to the adjacent electrodes6. , can easily cause third-order harmonic vibrations. [Effects of the Invention] As described above, the present invention provides a vertical crystal resonator with a new shape and facilitates third-order harmonic vibration in a vertical crystal resonator in which the vibrating part and the support part are integrally formed by an etching method. By proposing an electrode arrangement that excites the current, we have the following remarkable effects. - By improving the shape and dimensions of the support part, vibration can be made free, so loss resistance is reduced.

■Since there is a hole between the bending part and the frame, the vibrating part can vibrate freely, and at the same time, the energy of the bending part is not transmitted to the frame, so there is no vibration leakage, and the mount part Even if it is fixed, a vibrator with a small R1 can be obtained. ■The vibrating part is divided into three parts, and adjacent electrodes are configured so that voltages of different polarities are applied to them, making it easy to induce third-order harmonic vibrations and obtain higher frequencies. can.

■Since it is mounted on one side, it is easy to manufacture and can be made smaller.

[Brief explanation of drawings]

FIGS. 1(a) and 1(b) show an embodiment of the vertical crystal resonator shape and electrode arrangement of the present invention. FIG. 1(a) is a front view, and FIG. 1(b) is a bottom view. FIG. 2 is a simplified plan view for explaining the principle of the vertical crystal resonator of the present invention.・Support part 4...Bridge part 5...Bending part 6...Frame 7...88...Mount part 9, lO・...Excitation electrode 11.12... Electrode L. L. ... Length of bent portion W. W2... Width L1 of the bending part... Length W of the vibrating part. ... Width of the vibrating part T ... Thickness Main principle of small air gravity hand Traditional theory B month 1st edition: Meso-shouto-sha and shi-kam surface drawing Figure 2 Application People Seiko Electronic Components Co., Ltd.

Claims (1)

[Claims] A vertical crystal resonator in which the vibrating part and the supporting part are integrally formed by etching, and the vibrating part is connected to the bending part through the bridge part, and further connected to the frame through both ends of the hole. and a vertical crystal resonator extending to the mount section, wherein the excitation electrode provided in the vibrating section is divided into three parts, and adjacent electrodes are configured to be applied with voltages of different polarities. electrode structure.