JPS63285016A - Rectangular at vibrator for overtone - Google Patents

Abstract

PURPOSE:To lower the CI at overtone and make the CI for a fundamental wave higher than the CI at the third harmonic by selecting the radius of convex portion to be <=60mm so as to specify the length of the slope. CONSTITUTION:The slope is formed in the direction X of a rectangular AT vibrator chip 1 whose external size is <=7mm in the X direction, <=2mm in the Z' direction and <=0.24mm and >=0.12mm in the Y' direction by the convex processing and the radius R1 of the convex portion is selected to be <=60mm by forming the length of the oblique side to be <=0.9. Thus, the length of the major plane of the vibration chip is extended with the length of he slop de creased in such a way, the CI of the third harmonic wave is lowered because the vibration energy of the third harmonic wave is rised and since the fundamen tal wave reaches the support part 2 before the vibration energy is attenuated and the leakage of the vibration energy is increased and the CI of the fundamen tal wave is raised.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement of a vibrating element in an AT vibrator with a well-known overtone shape.

[Prior Art] In an AT resonator with a known overtone shape, it is necessary to lower the overtone IC.

Conventionally, in overtone well-known shape AT resonators,
In order to lower the CI of the overtone, the external dimensions are 8 mm in the X direction and 3 Il11 in the Z' direction, similar to the disc-shaped AT resonator.
By increasing the external dimensions and increasing the energy trapping effect, C
I was keeping I low.

[Problem that the invention seeks to solve]

However, there has been an increasing demand for miniaturization of AT resonators with the well-known overtone shape, but conventional technology has been able to
1 or less, and 36 MIIz when downsized to 21 or less in the Z' direction.
In the following models, energy confinement is no longer possible, and in models with a frequency of 36 MHz or less, the CI becomes high.

Furthermore, conventionally, the relationship between the CI of the fundamental wave and the third harmonic wave of an AT resonator has not been considered.

Therefore, the present invention is intended to solve such problems, and its purpose is to improve the overtone CI.
The overtone well-known shape AT41i mover of the present invention has an overtone shape that lowers the fundamental wave CI and has a fundamental wave CI higher than 3 times the CI.
A rectangular Δ′l′ vibrating piece with a dimension of 2 mm or less in the Y′ direction, 0.24 mm or less in the Y′ direction, and 12 mm or more is formed by convex machining in the X direction of the vibrating piece, and the length of the slope is reduced to 0.
．． The R dimension of the convex is set to 60 so that it is 9 mm or less.
It is characterized by being less than mm.

[Effect]

Since the present invention has the above configuration, since the length of the slope is shortened, the length of the main surface of the vibrating element becomes long, and as the vibration energy of the third harmonic increases, C1 of the third harmonic increases,
will go down.

In addition, as the length of the slope becomes shorter, the vibration energy of the fundamental wave reaches the holding part before being attenuated, which increases the leakage of vibration energy and therefore increases the CI of the fundamental wave. .

〔Example〕

Hereinafter, the present invention will be described in detail with reference to Examples.

FIG. 1 is a perspective view of an embodiment of the invention. In the rectangular AT vibrating piece 1, a slope is formed in the X direction, the slope is formed by an arc of Ro in the X direction, the length of the slope in the X direction is Xt, and the length of the end face in the X direction in the Y' direction. Yz,
The length of the rectangular AT oscillation piece in the X direction is X2, and the length in the Y' direction is Y.

far. A holding portion 2 is formed at the end of the rectangular AT oscillation piece in the X direction. The length of the holding portion in the X direction is X,
Too (, there is a relationship between Xyo and X3 as follows: Xt>Xs...(1).

X2 is χ2≦0.9ffi+s...(2) Xt and RI are selected so as to satisfy the equations (2).

Figure 2 shows the method of convex processing, R, (mm
) When the vibrating piece 1 and the abrasive 4 are mixed together in a ball or cylinder 3 having a circular shape and rotated in the direction of the arrow in the figure, the vibrating piece 1 will change the RI (mm) of the taste or cylinder 3. It is processed into the shape shown in FIG. 3 using the abrasive 4.

Here, between Xt and R, there is a machining finish, There is a relationship between

External X dimension, external Y' dimension of the actual overtone known shape AT resonator, length of slope in X direction, R dimension of slope in X direction, length of end face in X direction in Y' direction, third harmonic CI of
Table 1 shows the relationship between S-based CIs.

FIGS. 4(a) and 4(b) illustrate the relationship between the fundamental wave CI and the third harmonic Ct when R1 is changed.

As shown in FIGS. 4(a) and 4(b), it can be seen that when the Rt of the slope in the X direction is set to 50 mm or less, the CI of the third harmonic decreases and the CI of the fundamental wave increases.

In addition, when the above R is set to 50 mm or less, the above X2 is (3
), the specific values are shown in Table 1, and X2 is 0.9 mm or less.

Note that depending on the frequency, X2 may be set to 0.
R1 of 91 or less exists as much as 60 mm+, and although it is not shown in FIG. 4, the same result as that of RI of 50 mae or less is obtained.

Furthermore, up to now, the holding method has been explained only by holding one end of the rectangular AT oscillation piece in the X direction on one side, but as shown in Fig. 5(a) and Fig. 5(b), The present invention is also effective in a method of supporting both sides or both ends of the rectangular AT oscillation piece in the X direction.

Table 1 (Effects of the invention) As described above, according to the present invention, as the length of the slope is shortened, the length of the main surface of the vibrating piece becomes long, and the vibration energy of the third harmonic wave increases. Therefore, the CI of the third harmonic
It has the effect of lowering the

In addition, as the length of the slope becomes shorter, the vibration energy of the fundamental wave reaches the holding part before it is attenuated, which increases the leakage of vibration energy and therefore increases the CI of the zero wave. has.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an AT resonator with a known overtone shape according to the present invention. FIG. 2 is an explanatory diagram of a convex processing method. FIG. 3 is a perspective view showing a rectangular AT vibrating piece after convex processing. FIGS. 4(a) and 4(b) are relationship diagrams between the third harmonic CI and the fundamental CI when the R dimension of the slope in the X direction is changed. FIGS. 5(a) and 5(b) are perspective views showing another holding method of the present invention. l... Rectangular AT oscillation piece 2... Holding part 3... Ball or cylinder 4... Abrasive Xl... X direction length of rectangular AT oscillation piece... X direction of slope Length
Length R in the Y' direction of the end face in the X direction +...More than the dimension of the slope in the X direction

Claims (1)

[Claims] Rectangular AT with external dimensions of 7 mm or less in the X direction, 2 mm or less in the Z' direction, 0.24 mm or less in the Y' direction, and 0.12 mm or more
A slope is created by convex machining in the X direction of the vibrating piece.
A rectangular AT vibrator for overtones, characterized in that the radius R of the convex is set to 60 mm or less so that the length of the slope is 0.9 mm or less.