JPH02198213A - Overtone rectangular at vibrator - Google Patents

Abstract

PURPOSE:To prevent the effect due to spurious vibration by selecting the frequency change so that a ratio of the frequency change before and after the forming of the electrode on the major plane of the AT vibration chip to a ternary overtone frequency is within a specific range. CONSTITUTION:The overtone rectangular AT vibrator consists of an overtone rectangular vibration chip 1 with an electrode 2 formed thereto, an inner lead 5 at one end of two lead terminal 4 penetrated to an air-tight terminal 3 and one side width of the electrode 2 soldered by an adhesives such as solder 6. The outside dimension of the vibrator chip 1 is selected such that the length in the X' direction is 8mm or below, the length in the Z' axis is 3mm or below and the length in the Y' axis is 0.5mm or below. Then the relation of 370< f/f<670 exists where f is a frequency change before and after forming of the electrode 2 on the major plane (in the unit of ppm) and f(MHz) is the frequency of te ternary overtone. Thus, the effect due to spurious vibration is prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention uses a rectangular crystal piece cut by an AT cut to produce a rectangular AT for overtone that performs high frequency oscillation.
Regarding oscillators.

[Conventional technology]

Among the many crystal resonators currently available, the most versatile one is the AT resonator.

This AT resonator has relatively good frequency-temperature characteristics (hereinafter abbreviated as temperature characteristics) and is therefore used in consumer devices such as communication device clocks.

Conventionally, there has been only a disk AT resonator as an AT resonator.

However, in recent years, electronic equipment has become smaller and lighter, and crystal resonators are also required to be smaller.

Therefore, AT resonators have been manufactured that are machined into a rectangular shape that is long in the X-axis direction, with the X-axis having a length of 1, the Z'-axis having a width of W, and the Y'-axis having a thickness of 7.

[Problem to be solved by the invention]

However, in addition to the main vibration, a rectangular AT resonator for overtones usually has spurious vibration near the frequency of the main vibration, which has a particularly negative effect on temperature, and also has a series resonance resistance (hereinafter abbreviated as cry). The problem was that it was expensive.

The present invention aims to solve the above-mentioned problems, and its purpose is to provide a method of preventing the influence of spurious vibrations and a method of lowering the CI value in a rectangular AT resonator for overton use.

[Means to solve the problem]

(1) The rectangular AT vibrator for overton according to the present invention has external dimensions of 8 mm or less in the X-axis direction, 3 mm or less in the Z'-axis direction, and Y'
Overtone known shape AT of 0.5++m or less in the axial direction
Let △f be the amount of frequency change before and after forming the electrode on the main surface of the vibrating element. However, the unit of △f is p p n'l.)
, where f (MHz) is the frequency of the third-order overton, 370 Δf , z f < 670.

(2) In the rectangular AT resonator for overtone according to the present invention, in the rectangular AT resonator for overtone described in the above item 1, the Z' axis of the rectangular AT vibrator for overton is @W, Y When the axis is the thickness t, the side ratio w between the width W and the thickness t, 't is the following range W/l = 8.4 ±0.2 w/1 = 10.64 ± 0.2 w/1 =11.85±0゜15 w7't=13.45±0.15 w/l, =14.8 ±0.2 w/1=17.6 ±0,2 w/1=19.8 ± 0.2 w, 't=20.9 ±0,2.

[For production]

Since the present invention has the above configuration, the amount of frequency change (hereinafter abbreviated as △) before and after forming the electrode on the main surface of the overtone well-known shape AT vibrating piece, and the overtone
- By appropriately selecting the width W and thickness t of the rectangular AT vibrating piece, spurious vibrations can be suppressed and CI[ can be lowered.

〔Example〕

Hereinafter, the present invention will be described in detail based on examples.

FIG. 1 is a perspective view showing one embodiment of a rectangular AT resonator for overtone according to the present invention. The rectangular AT vibrating piece 1 for tons, the inner lead 5 at one end of the two lead terminals 4 that pass through the airtight terminal 3, and the mold! 2 is fixed with an adhesive such as solder 6, and a gauge 7 is press-fitted into the airtight terminal 3.

Further, the overtone shaped AT vibrating piece 1 shown in FIG. 1 has a thickness t in the Y'-axis direction and a width W in the z'-axis direction.

Also, at this time, the side ratio w7't of width W and thickness t is w/l
w and t are selected so that =8.4±0.2.

FIG. 2 is a diagram showing the relationship between Δf and CI.

FIG. 2(a) is a correlation diagram between Δf and CI when the frequency is changed. Looking at the figure, it can be seen that as the frequency increases, the CI decreases even if Δf is small. Also, if the △ is too large for each frequency, the CI value tends to increase, but this is quality! It is said that the vibration has become difficult to excite due to the addition of the filter.

In addition, Fig. 2(b) shows Δf/f when the frequency is changed.
It is a correlation diagram between and CI. Looking at the same figure, regardless of the frequency, as Δf/'f increases, CI decreases, and Δf/'
If f becomes too large, the CI value tends to become high, and this is for the reason mentioned above.

Therefore 370 Δf /' f < 670 If so, it can be seen that the CI value is low.

In particular, it can be seen that the CI value is lowest near Δf/,' f = 520 (=f).

Figure 3 shows the frequency of the main vibration of the third overtone (hereinafter abbreviated as Fo) and the spurious frequency (hereinafter abbreviated as F).
It is a figure showing the relationship between ratio F/'Fo and w7't.

The solid line is the relationship between F/FO and w/t of only the foot-shaped AT vibrating piece 1 for overtone, and the broken line is the relationship between the F/FO and w/t of the foot-shaped AT vibrating piece 1 for overtone. This is the relationship between F, /F0 and w/l when formed.

As can be seen from the figure, the F/F when the electrode is formed on the main surface of the foot-shaped AT vibrating piece for overtone, and the F/F of only the foot-shaped AT vibrating piece for overtone.
It can be seen that the positional relationship of o has changed.

This is because the amount of frequency reduction with respect to the mass of the electrode is different between the main vibration of the tertiary overtone and the spurious, and the amount of frequency reduction with respect to the same mass of the electrode is greater in the main vibration of the tertiary overtone.

As can be seen from FIG. 3, the values of the spurious-free j&optimum ratio before and after vapor deposition deviate.

FIG. 4 is a diagram showing the temperature characteristics when the side ratio w 7' t is changed.

Figure 4 (a) shows the temperature characteristics when the side ratio w/l is W/t = 8.4 0.2, and ripples begin to occur on the low temperature side due to the influence of spurious components. I know that there is.

Further, FIG. 4(b) shows the temperature characteristics when the side ratio W/'t is set to w/l=8.4, and it can be seen that there is no influence of spurious components and no ripples occur.

Figure 4 (c) shows the temperature characteristics when the side ratio W/t is W/t = 8.4 + 0.2, and ripples are starting to appear on the high temperature side due to the influence of spurious. I understand that.

Therefore, by setting the side ratio w/l to w/l = 8.4±0.2, spurious vibrations exist near the frequency of the main vibration of the third-order Overton and do not have any adverse effect on temperature. Defects can be suppressed.

Further, the same effect can be obtained for other side ratios w7't of the present invention, and the side ratios are set in the following range w/1=10.64±0.2 w/1=11.85±0.15 W/ t=13.45±0,15 w/1=14.8 ±0.2 w/1=17.6 ±0.2 w/1=19.8 ±0.2 w/l=・20.9 By setting the value to ±0.2, it is possible to suppress the drawback that spurious vibrations exist near the frequency of the main vibration of the tertiary overtone and have a particularly negative effect on temperature.

In addition, the foot-shaped AT vibration pieces for overtones have been
Although the explanation has only been made using a rectangular parallelepiped, Figs. 5(a) and 5(
Even if the foot-shaped AT vibrating piece for overtone is subjected to convex processing or bevel processing as shown in b), the same result can be obtained by measuring the thickness t at the thickest central portion.

Therefore, the present invention is effective even if the overtone foot-shaped AT vibrating piece is subjected to convex processing or bevel processing as shown in FIGS. 5(a) and 5(b).

〔Effect of the invention〕

As described above, according to the present invention, by appropriately selecting Δf so that 370×Δf/f<670, CI
At the same time, by appropriately selecting the width W and thickness t of the foot-shaped AT vibrating piece for overtone, it is possible to prevent the influence of spurious vibrations.

airtight terminal lead terminal inner lead solder Case

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an AT resonator with a well-known overtone shape according to the present invention. FIGS. 2(a) and 2(b) are relationship diagrams between Δf and CI, or Δf/f and CI. FIG. 3 is a diagram showing the relationship between F/'F o and w/l. FIGS. 4(a) to 4(C) are diagrams showing the temperature characteristics when the side ratio w/l is changed. FIGS. 5(a) and 5(b) are perspective views showing other embodiments of the foot-shaped AT vibrating piece for overtone according to the present invention.

Claims (2)

[Claims] (1) External dimensions: 8 mm or less in the X-axis direction, 3 mm in the Z'-axis direction
Hereinafter, in a rectangular AT vibrating piece for overton with a diameter of 0.5 mm or less in the Y' axis direction, the amount of frequency change before and after forming an electrode on the main surface is defined as Δf (however, the unit of Δf is ppm),
A rectangular AT vibrator for overtones, characterized in that the frequency of the third overtone is f (MHz), 370<Δf/f<670. (2) Rectangular AT for overtone according to claim 1
In the vibrator, when the Z' axis of the rectangular AT vibrating piece for overtone is the width W and the Y' axis is the thickness t, the side ratio W/t of the width W and the thickness t is within the following range W/t= 8.4±0.2 W/t=10.64±0.2 W/t=11.85±0.15 W/t=13.45±0.15 W/t=14.8±0. 2. A rectangular AT vibrator for overtone, characterized in that W/t=17.6±0.2 W/t=19.8±0.2 W/t=20.9±0.2.