JP2709315B2 - Free-ended bending quartz crystal unit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a free-ended bent quartz crystal resonator having a low frequency of 100 KHz to 500 KHz. In particular, it relates to the shape of the vibrator and the arrangement of the excitation electrodes, and relates to a free-ended bent quartz crystal vibrator which has been actively developed recently and is optimal as a reference signal source for portable devices such as pagers and IC cards.

[Summary of the Invention]

Crystal BACKGROUND OF THE INVENTION Physical and is chemically very stable substance, therefore, formed therefrom, so-called crystal oscillators small loss resistance R _1, the vibrator having a high Q value Obtainable. Therefore, it has been frequently used as a time or frequency reference source for various devices. In particular, recently, miniaturization of various devices and development of new products have been actively performed.
For example, an ultra-thin crystal resonator such as an IC card is required, and a demand for a frequency reference source of several hundred KHz is increasing. The present invention has been made in view of the above.

(Object of the present invention) That is, an object of the present invention is to provide an ultra-thin free-ended bending quartz crystal resonator having a frequency of 100 KHz to 500 KHz, having very little vibration leakage, a small loss resistance R ₁ , and a high Q value. Is to do.

(Summary of the Present Invention) As described above, quartz is a very stable substance, so that an excellent quartz resonator can be obtained. However, such excellent characteristics can be obtained only when a vibrator shape with small vibration leakage is obtained. In the present invention, the vibrating portion and the supporting portion that bend and vibrate are connected to the supporting portion via a bridge portion at a position serving as a node of the vibrating portion of the bent quartz-crystal vibrator integrally formed by an etching method.
By making the shape of the support part new, the energy of the vibrating part is confined inside the vibrating part. As a result, small loss resistance R _1, and can obtain a high Q value across freestyle flexural quartz oscillator. Further, in order to obtain a frequency of several hundred KHz, in the present invention, the vibrator has a boundary condition free of both ends. Therefore, since the frequency constant is 6.4 times larger than the tuning fork shape having the same width and length,
Higher frequencies can be obtained.

[Conventional technology]

As a low-frequency vibrator, there is a tuning-fork type bent quartz crystal vibrator, but in order to further increase the frequency, harmonic vibration must be used. For this reason, the arrangement of the excitation electrodes becomes complicated, and problems such as an increase in the capacitance ratio, which is one of the electrical characteristics, occur. In addition, the use of harmonic vibrations, when mounted in fork base, vibration leakage is large, very difficult to obtain a small oscillator loss resistance R _1. Further, the frequency of the tuning-fork type bent crystal resonator is considered to be about 200 KHz when considered at the mass production level, and the 500 KHz bending crystal resonator of the present invention has not yet been put to practical use. In addition, the conventional free-form bending quartz oscillator with both ends is 100 KHz.
If the size is further reduced, the support method becomes difficult, and the loss resistance
There is R ₁ problems weak like very larger and at the same time the impact has not yet been put to practical use.

[Problems to be solved by the invention]

As described above, the conventional tuning-fork type bent crystal resonator has a limit in increasing the frequency, and at the same time, the loss resistance R ₁
There have been many problems such as an increase in capacity and an increase in the capacity ratio.
In addition, it is difficult to reduce the size of a conventional free-ended bent quartz crystal resonator by machining, and it has not been possible to increase the frequency.

[Means for solving the problem]

In order to solve the above-mentioned problem, in the present invention, excitation electrodes are arranged on four surfaces of upper and lower surfaces and side surfaces of a free-ended bent quartz-crystal vibrator having a rod-shaped vibrating portion, and upper and lower surfaces and two side surfaces of the vibrator are the same. A pole excitation electrode is formed, and the vibrating portion is connected to two first frames provided symmetrically with respect to the vibrating portion via a first bridge portion, and further, the central portions of the two first frames are connected to each other. The two frames are connected to the two second frames via the second bridge portions, and the second frames are closed and extend to the mount portion, and the first frame and the second frame are integrally formed from the same crystal wafer. The excitation electrode disposed on the vibrating portion extends to the mount portion via the upper surfaces of the first frame and the second frame, and is configured to be divided by the mount portion, so that the frequency constant of the vibrator is adjusted by the tuning fork. Approximately 6.4 times that of a bent quartz crystal resonator Ri, 500KHz, which is an object of the present invention
Not only it is possible to obtain an oscillator of high frequency of a small loss resistance R _1, excellent vibrator impact resistance can be obtained.

[Action]

Since the vibrator of the present invention is connected to the supporting portion via the bridge portion at the node of the vibrating portion, and is formed integrally by the etching method, it is small, has small vibration leakage, and is relatively high at 500 KHz. Frequency can be realized in bending mode. Furthermore, since quartz is used as the material,
And a crystal resonator that is chemically stable and thus has high frequency stability is obtained.

〔Example〕

Next, examples of the present invention and the results obtained therefrom will be specifically described. FIG. 1 is a plan view of one embodiment of a free-ended bent quartz-crystal vibrator of the present invention. A vibrator 1 is composed of a vibrating part 2 and a support part 3 via a first bridge part 4, and is integrated by an etching method. Is formed. Note that the support portion 3 is the first
It comprises a frame 5, a second bridge section 6, a second frame and a mount section 8, and an electrode 11 and an electrode 12 are arranged on the first frame 5 and the second frame 7, respectively. Also, the vibrating part 2
, The excitation electrodes 9 and 10 are arranged on the side surfaces facing the upper and lower surfaces facing each other. That is, FIG. 2 is a cross-sectional view taken along the line AA 'of FIG. 1. The two side electrodes have the same polarity (a), and the two upper and lower electrodes also have the same polarity. Thus, at the same time as (b), the electrodes are formed to have different polarities. More specifically, the excitation electrodes 9 and 10 are connected to the electrodes 12 and 11 on the first and second frames, respectively, and are arranged on the same plane in the mounting section 8 so as to have different polarities. Although not shown, each electrode is 2
The lead wire of the external terminal is supported and fixed and electrically connected to the lead wire of the book by soldering or a conductive adhesive. Therefore,
By applying an alternating voltage to the two lead terminals,
The vibrating part 2 vibrates in a bending mode in the xy plane (x: electric axis of crystal, y: mechanical axis of crystal). At this time, since the first bridge portion is a node of the vibration, the displacement is almost zero, and the energy of the vibrating portion is hardly transmitted to the first frame 5. At the same time, the vibrator moves from the first frame 5 to the second frame.
Since the second frame 7 is formed via the bridge portion 6 and is supported and fixed by the mount portion 8, the vibration energy of the vibration portion is confined in the vibration portion and is not transmitted to the mount portion. Therefore, a bent quartz-crystal vibrator having no vibration leakage can be obtained even if it is supported and fixed to a lead wire or the like by the mount portion 8.

〔The invention's effect〕

As described above, the present invention provides the following remarkable effects by proposing a new-shaped free-end bent quartz crystal resonator in a bent quartz crystal resonator in which the vibrating portion and the support portion are integrally formed by an etching method. Having.

Devising the shape of the support portion, by improving, without suppressing the vibration of the vibration part, since it is possible to freely, loss resistance R ₁ becomes smaller.

Since a shape that connects to the support part via a first bridge portion in the section of the vibrating part, no vibration leakage, be supported fixed in the mount portion, a small vibrator loss resistance R ₁ can be obtained.

Since it is a free-ended vibrator, the frequency constant becomes larger than that of a conventional tuning-fork type bent crystal resonator, and a bent crystal resonator having a high frequency can be obtained.

Since it is mounted on one side, it can be easily manufactured and can be reduced in size.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of the shape of a free-ended bent quartz-crystal vibrator and excitation electrodes according to the present invention. FIG. 2 is a sectional view taken along the line AA 'of FIG. DESCRIPTION OF SYMBOLS 1 ... Vibrator 2 ... Vibration part 3 ... Support part 4 ... First bridge part 5 ... First frame 6 ... Second bridge part 7 ... Second frame 8 ... Mount part 9, 10 ... … Exciting electrodes 11, 12… Electrodes x, y, z… Electrical axis, mechanical axis, optical axis θ… Cut angle

Claims (1)

(57) [Claims] 1. Exciting electrodes are arranged on four sides of upper and lower surfaces and side surfaces of a double-sided free-type bent quartz crystal resonator having a rod-shaped vibrating portion, and upper and lower surfaces and two side surfaces of the vibrator are respectively provided with excitation electrodes of the same polarity. The vibrating part is connected to two first frames provided symmetrically with respect to the vibrating part via the first bridge part, and the central part of the two first frames is connected to the second bridge part. The second frame is connected to the second frame via the second frame, and the second frame is closed and extends to the mount portion, and the vibrating portion, the first bridge, the second bridge, the first frame, and the second frame are made of the same crystal. Excitation electrodes formed integrally from the wafer and arranged in the vibrating section are connected to the first frame and the second frame.
A double-sided free-form bent crystal resonator, which extends to a mount portion via an upper surface of a frame and is divided by the mount portion.