JPS5936413A - Tuning fork vibrator - Google Patents

Abstract

PURPOSE:To obtain a tuning fork vibrator where oscillation leakage is less and the Q value is high and characteristics are stable and a ratio of the width of a tuning arm to the length is a specific value or larger, by making a base part of the vibrator longer than the tuning arm. CONSTITUTION:In the tuning fork vibrator where a ratio w/l of a width (w) of a tuning fork 61 to a length l of the tuning fork 61 is set to >=0.2 to make the frequency higher, a ratio lb/l of a length lb of a base part 62 to the length l of the tuning fork 61 is set to >=1 to reduce a displacement u'y of the base part 62.

Description

[Detailed description of the invention] The present invention relates to the shape of a tuning fork type vibrator.

As is well known, tuning fork type vibrators and shunted tuning fork type crystal vibrators are widely used as vibrators for wristwatches and other relatively low frequency vibration sources. However, as the demand for high frequencies has increased in recent years, there have been no attempts to obtain high frequencies even with tuning fork type crystal resonators.

Figure 1 shows a plan view of a tuning fork crystal resonator.
The axis is the electrical axis of the crystal, and the y/ and z/axes are the mechanical and optical axes of the crystal, respectively, rotated by arbitrary angles around the electrical axis, and have nine directions. In the same figure, l and W are tuning forks. It represents the length and width of the arm. The part having a length of lb other than the two tuning fork arms will be called the base.

Normally, the frequency of a tuning fork type crystal oscillator used in a wristwatch is set to 32.768 KHz. In this case, the length-to-width ratio W// of the tuning fork arm has a value of approximately 0.1. Under this condition, the displacement at the base of the tuning fork crystal resonator is small, and the vibration energy of the resonator hits the support material. There is almost no chance that it will spread to the outside world. For this reason, it has been impossible to obtain an extremely stable tuning fork type crystal resonator having a high Q value and low equal resistance FT.

By the way, the tuning fork type vibrator is used by making bending vibration, and the frequency is proportional to vt/l''.As is clear from this, it is necessary to raise the frequency (by shortening r or by shortening r).
Just make W thicker. Among the vibration displacements in the three directions of the length, width, and thickness of the vibrator, the largest displacement component is the displacement in the length direction at the base of the tuning fork type camera element. If W is set higher or e is set shorter in order to increase the frequency, that is, if the value of Wle is increased, the displacement in the longitudinal direction of the vibrator at the base becomes large, especially when w// is 0.2 or more. ”
As a result, in the case of a tuning fork type vibrator with a large value of w//, an image of Because of the vibration leakage, it is a vibrator with high non-resistance EI, low Q value, and unstable characteristics, with small vibration leakage, high Q value, and stable characteristics h and vt/e values of 0. The purpose of this invention is to provide two or more tuning fork type vibrators. Hereinafter, the present invention will be described in detail with reference to the drawings [7].

FIG. 2 shows a plan view of a tuning fork type crystal resonator. 2
1, 22, and 23 represent six straight lines along the length of the tuning fork crystal resonator at the base of the resonator. It is also a graph showing the longitudinal displacement u y / of the vibrator during bending vibration. The curves at 51°, 52° and 63 represent u y / on the straight line 21° and 22.23 shown in FIG. , as is clear from FIG. 6, at the longitudinal end of the base, u y on the straight line of the 4-tree shown in FIG.
/ are almost equal. W/I! This also applies when the You can go with a thickness of u y /.

Figure 4 shows the relationship between the longitudinal displacement u y / of the oscillator at point C shown in Figure 2 and the length eb of the base of the tuning fork crystal oscillator when woe is approximately 03. It is a graph. The vertical axis is u y ' at point C, and the horizontal 'tilflH/b
represents the ratio of the length of the tuning fork arm - ye. However, the length of the tuning fork arm -ye is constant, tp, as is clear from Figure 4 (
,/? When b/j' is less than 1, u at point C
y/ increases rapidly. Also, when eb becomes thicker than E, the value of u y / approaches a constant value, and in this way,
In a tuning fork crystal resonator with a large value of Wle, if the length of the base is greater than the length of the tuning fork arm -FH, the displacement of the base will be small. The present invention provides a tuning fork type vibrator with Wle of 0.2 or more, in which the length of the base is l! It is characterized in that b is larger than the length e of the tuning fork arm. According to the tuning fork type vibrator of the present invention, when supported at the base, there is little vibration leakage (as a result, it is possible to obtain a stable tuning fork type vibrator with high Q value characteristics. A tuning fork crystal oscillator that utilizes elastic coupling of bending vibration and torsional vibration has been proposed as a precision camera.In this case, an elastic coupling of secondary vibration of bending and fundamental vibration of torsion is used. However, when using the elastic coupling of the fundamental vibration of bending and the fundamental vibration of torsion, Jri, compared to the case of using the elastic coupling of the secondary vibration of one song and the fundamental vibration of torsion J1σ) When making a two-crystal oscillator using the photolithography process, which requires a very small oscillator to obtain the same frequency, the oscillator must be must have a thickness of 50 μm or more. Under these conditions, in order to stimulate the elastic coupling of flexural vibration and torsional vibration, the width-to-length ratio Wle of the tuning fork arm must be 02 or more. Something is necessary.

The vibration displacement at the base of a tuning fork crystal resonator is
Among the displacement components in the three directions of the length, width, and thickness of the vibrator, the displacement uz' in the thickness direction is the largest, and FIG. It is a graph showing the displacement uZ' in the thickness direction of the vibrator due to torsional vibration. 51 is the ratio eb/l of the length eb of the base and the length e of the tuning fork arm
! The value of approximately 0.5.52 is l! The value of b// is approximately 1.
53 is l! This is when the value of b/e is approximately 2. however,
This result shows that the value of the width-to-length ratio vr/e of the tuning fork arm is 0.
This is from when I was 3 years old. As is clear from Fig. 5, the tilt vibration peculiar to the torsional vibration at the base is eb/l! When the value of is greater than 1, it becomes very small. Even if the vibration used is bending vibration, if there is an elastic coupling with torsional vibration, the bending vibration will also have a displacement component of torsional vibration. For this reason,
The bending vibration itself also has a tilt vibration peculiar to torsional vibration at the base.If eb/e is 1 or more, the bending vibration combined with the torsional ha motion has a small a(1) at the base.For this reason, w// is The tuning fork type vibrator of the present invention having a lb/l value of 0.2 or more and 1 or more had some vibration leakage even when supported at the base d).Providing a highly stable vibrator with a high Q value. FIG. 6 is a plan view of a tuning fork type crystal resonator showing an embodiment of the present invention. 61 represents a tuning fork arm, 62 represents a base, W/l is 0.2 or more, and eb/l is 1 or more.

In the above description, a crystal resonator was mainly used as an example of a tuning fork type resonator, but the effects of the present invention are not limited to crystal resonators. Even if the material of the vibrator is other than crystal, the effects of the present invention are still applicable.

As explained in detail above, the present invention has a slight vibration leakage.
Therefore, it has the advantage of providing a relatively low frequency tuning fork type vibrator with low equivalent resistance B l %, high Q value, and stable frequency aging characteristics.

[Brief explanation of drawings]

Figures 1 and 2 are plan views showing a tuning fork type crystal resonator.
The figure is a graph showing the displacement of bending vibration at the base of a tuning fork crystal resonator, and Figure 4 shows the displacement of bending vibration at the base end of tuning fork crystal resonators with different base lengths. FIG. 5 is a graph showing the displacement of torsional vibration at the base end of tuning fork crystal resonators with different base lengths, and FIG. Top view of the child. 61... Tuning fork arm 62... Applicant above base W Nikiseikosha Co., Ltd. Patent attorney Mogami Tsutomu

Claims (4)

[Claims] (1) The ratio w/1 of the width W of the tuning fork arm and the length l of the tuning fork arm is 0,
In two or more tuning fork type image sensors, the length l of the base of the vibrator
b is the length of the tuning fork arm ζ/! A tuning fork type vibrator characterized by a long edge. (2) A tuning fork type vibrator according to claim 1, characterized in that the vibrator vibrates only with a bending vibrator. (3) A tuning fork type vibrator according to claim 1, characterized in that the vibrator is a vibrator that utilizes elastic coupling of bending vibration and torsional vibration; (4) A tuning fork type vibrator 6 according to any of claims 1, 2, and 3, characterized in that the vibrator is a crystal vibrator.