JPH03150911A - Harmonic wave coupling vibration - Google Patents

Abstract

PURPOSE:To make the coupling between long side vibration and short side vibration stable and to obtain a high accuracy temperature characteristic by forming integrally a support in the vicinity of a nodal point of the vibration generated at 3 division points of each side by a 3rd harmonic vibration. CONSTITUTION:Let a size of a short side of a vibration section 1 be W and a size of a long side be L, then broken lines show one maximum displacement of the vibration of a 3rd harmonic wave, a vibration displacement UL is a long side vibration displacement and a vibration displacement UW is a short side vibration displacement. Four supports in parallel with the long side direction are formed integrally in the vicinity B of two nodal points near the middle among 3 division points of the end face of the long side vibration part. Thus, the coupling between the long side vibration and the short side vibration is made stable and a high accuracy temperature characteristic is obtained.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to high-precision coupled resonators used in fields such as microcomputers and cordless telephones, and fields such as automobile radio and aviation radio, particularly GT-cut It relates to crystal oscillators.

[Summary of the Invention] The present invention provides a harmonic-coupled resonator that realizes highly accurate temperature characteristics by utilizing the coupling of two vibration modes, particularly a GT-cut crystal resonator that vibrates at the third harmonic. , 3rd
By integrally forming a support near the nodal point of vibration generated at the three-division point of each side due to harmonic vibration, the coupling between long side vibration and short side vibration is stabilized, resulting in high precision. This is to obtain temperature characteristics.

[Conventional technology 1] As a vibrator that utilizes the combination of long-side vibration and short-side vibration (
The known GT cut crystal resonator is well known for its very good temperature characteristics.

Here, the temperature characteristic is a change in frequency with respect to a change in temperature. By the way, for GT cut crystal resonators,
Regarding its temperature characteristics, vibration theory predicts that the frequency change rate will be within ±2 ppm in the temperature range from -30°C to 70°C.

Furthermore, oscillation circuits using crystal resonators are becoming more modular and multifunctional. Recently, in response to market demands, higher frequency reference signals have been desired, and by shortening the dimensions of each side of GT cut crystal resonators,
Higher frequencies are desired. However, in a GT-cut crystal resonator, there are limits to its shape and dimensional accuracy due to processing constraints resulting from its manufacturing process, and it is extremely difficult to increase the frequency by simply reducing the shape and dimensions. Therefore,
Recently, attention has been paid to high-frequency crystal resonators using an overtone vibration mode under constant shape conditions, that is, harmonic GT-cut crystal resonators.

FIG. 2 is a plan view showing the shape of a conventional GT-cut crystal resonator and the vibration mode due to the third harmonic. In the figure, 1 is a vibrating part, and 2 is a supporting part. Furthermore, the broken line indicates the deformation of one of the vibration modes. In this vibration mode, the displacement indicated by the arrow Uw is the short side vibration displacement and the long side vibration displacement UL. At this time, if we pay attention to the short side vibration displacement Uw, it has four nodal points ■ and six maximum displacement points ■. These two nodal points {circle over (2)} are points that approximately divide the vibration long side dimension W into three equal parts. Similarly, regarding the long side vibration displacement UL, there are four nodal points ■ and six maximum displacement points ■. Furthermore, these two nodal points (2) are points that approximately divide the vibration long side dimension into three equal parts.

[Problems to be Solved by the Invention] In the conventional structure described above, since the support part 2 is formed near the maximum point 0 of the long side vibration displacement UL, the elastic properties of the long side vibration and the electric This greatly impedes the characteristics of Therefore, the coupling between long-side vibration and short-side vibration is extremely unstable, and there is a problem in that it is difficult to realize the highly accurate temperature characteristics inherent to a GT cut resonator.

The present invention provides a GT-cut crystal resonator using the third harmonic, with the aim of eliminating the above-mentioned problems, easily realizing the original high-precision temperature characteristics, and realizing a small size. It is something.

[Means for Solving the Problems] In order to obtain the above-mentioned GT-cut crystal resonator, the present invention provides a vibration mode in which a vibrating part and a support part are integrally formed, and a long side vibration and a short side vibration are combined, In a harmonic-coupled vibrator that vibrates due to third-order harmonics, the supporting portion is placed near two points near the center of each of the two long sides and/or two short sides of the vibrating portion divided into three. The goal is to be achieved by forming it.

[Function] Next, the function and effect of the present invention will be explained in detail. FIG.
In Figure 0, which is a plan view of one side portion illustrating long side vibration displacement, 1 is a vibrating portion.

In the vibrating section 1, the long side dimension is W, and the short side dimension is W. The broken line in FIG. 1 is the long side vibration displacement UL. As explained in FIG. 2, this line L has two nodal points ■ and three maximum displacement points ■.

In the conventional vibrator illustrated in FIG. 2, a support portion is integrally formed in the portion A in FIG. This part A is near the maximum displacement point (2). In this case, the long side vibration is significantly suppressed due to the stress applied by the support part formation.
As mentioned above, this leads to an unstable bonding state.

On the other hand, consider the case where the support portion is formed in the vicinity of the nodal point {circle around (2)}, that is, in the 8th part. At the nodal point ■, the vibration displacement UL is constantly O. Therefore, even if stress is applied to this part, it will not affect the vibration, that is, a stable coupling state will be maintained, and the original ultra-high precision temperature characteristics can be achieved even at the third harmonic.

As described above, the vibration displacement in the vicinity of the nodal point of vibration is very small. Therefore, even if the support part is integrally formed in this part, it will not affect the elastic and electrical characteristics of vibration. As a result, the coupling between long-side vibration and short-side vibration is
It was extremely stable and achieved highly accurate temperature characteristics.

[Example 1] First, a major feature of the coupled vibrator according to the present invention is that ultra-high precision temperature characteristics can be obtained by elastically and electrically coupling long-side vibration and short-side vibration. In order to obtain such characteristics, it is necessary to realize stable coupling of both vibrations.

FIG. 1 is a plan view of an embodiment based on the present invention.
In the figure, 1 is a vibrating part, the short side of which is W, and the long side of which is L. Furthermore, the dashed line indicates the maximum displacement of one of the third harmonic vibrations. Vibration displacement tJL
is the long side vibration displacement, and Uw is the short side vibration displacement.

Reference numeral 7 denotes four supporting parts parallel to the long side direction, and these supporting parts 7 are integrally formed from a part 0 near a nodal point consisting of two points near the center of the end face of the long side vibrating part divided into three parts. There is. The shape of the integrally formed support part 7 can be arbitrarily selected depending on the shape of the vibrator container and other conditions, and may be, for example, the shape of the support part 2 shown in FIG. 1.
This is because the shape of the support part does not affect the long-side vibration since the support part is integrally formed from the 0 part near the nodal point.

In the above embodiment, four supports 7 are provided on the end faces in the long side direction, but according to this theory, the same effect can be obtained even if the support parts 7 are provided at two points on each side in the short side direction. Furthermore, it is optional to provide support portions on both the long sides and the short sides, if necessary.

Next, the graph of FIG. 4 is a graph showing the frequency-temperature characteristics of the third-order harmonic coupled resonator before implementation of the present invention. The vertical axis of the figure is the frequency change rate (ppm), and the horizontal axis is the temperature.The temperature characteristics have a large variation, and the ±2 ppm that the original GT cut crystal resonator should have.
However, the graph in Figure 5 shows the frequency-temperature characteristics of a third harmonic coupled resonator according to the present invention, and the vertical and horizontal axes are , is the same as in FIG. In Figure 5, the variation in temperature characteristics is very small (approximately ±3 ppm).
It can be seen that the stability of the bond is significantly increased by forming the support part from the notal point.

[Effects of the Invention] As described above, by carrying out the present invention, even if the dimensions are the same as those of the conventional device, the frequency is three times higher, and the temperature characteristics can be as highly accurate as ±2 ppm.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a vibrator according to an embodiment of the present invention. FIG. 2 is a plan view showing the shape and vibration displacement of a conventional third-order harmonic coupled vibrator. FIG. 3 is a plan view showing the main parts of the present invention, the nodal point, and the maximum displacement point. FIG. 4 is a graph showing the frequency-temperature characteristics of a third-order harmonic coupled resonator in a conventional shape. FIG. 5 is a graph showing the frequency-temperature characteristics of the third-order harmonic coupled resonator according to the present invention. 1 ・ 2 ・ ■・ ■・ ■・ ■・ ■・ ■・ 7 ・ L Nodal point due to short side vibration of the vibrating part support Maximum displacement point due to short side vibration Nodal point due to long side vibration Maximum displacement point length due to long side vibration Maximum displacement point of side vibration Nodal point of long side vibration Support part of the present invention 3rd harmonic wavelength Side vibration displacement Llw ・ W ・ 3rd harmonic wavelength Side vibration displacement Long side dimension of the vibrating part Short side dimension of the vibrating part

Claims (1)

[Claims] In a harmonic-coupled vibrator in which the vibrating part and the support part are integrally formed, the vibration mode is a combination of long side vibration and short side vibration, and the vibration mode is vibrated by a third harmonic, two of the vibrating parts
A harmonic coupling vibrator characterized in that the supporting portions are formed in the vicinity of two points near the center of three long sides and/or two short sides divided into three.