JPS6021614A - Supporting structure of tuning fork crystal oscillator - Google Patents

Abstract

PURPOSE:To improve shock resistance characteristic by supporting a tuning fork type crystal oscillator by two supporting members in common use for leads having a Young's modulus within a prescribed range. CONSTITUTION:The total length L of the tuning fork type crystal oscillator 111 is 3.3mm., the length la of the tuning fork arm is 1mm., the length lb of the base part is 2.3mm., the length lc of the concaved part is 0.6mm., the maximum width W of the oscillator 111 is 1mm., the amount of cut (w) of the concaved part of the base part is 0.2mm., and the thickness of the oscillator 111 is nearly 55mum. The Young's modulus of the lead 112 made of ''Kovar'' is nearly 14,000kg/mm.<2>, the thickness of the lead 112 is 125mum and the distance lL between the base part end of the oscillator 111 and a plug 113 is 300mum. Through the constitution above, the supporting structure of the tuning form type crystal oscillator 111 having the concaved part to the base part is excellent against hock and the support does does not break even if it is dropped from a height of nearly 1m onto a concrete plate.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a support structure for a tuning fork type crystal resonator having a recessed portion at its base.

<Prior Art> In recent years, tuning fork type crystal resonators that produce torsional vibration have attracted attention. The reason for this is that the frequency of torsional vibration is higher than the 61 wave number (when the same tuning fork type crystal oscillator is subjected to bending vibration), and the frequency is lower than that of an AT crystal that uses thickness shear vibration of 11fl. This is so that you can be saved.

Attempts have also been made to utilize elastic coupling between bending vibration and torsional vibration to obtain a crystal resonator for a wristwatch with high accuracy, such as an annual difference of several seconds.

As long as a tuning fork type crystal resonator uses torsional vibration, the vibration displacement at its base is extremely large, regardless of whether it uses torsional vibration alone or an elastic combination of bending vibration and torsional vibration. . The displacement in the thickness direction of the tuning fork + hi + tip vibrator is the maximum displacement of torsional vibration, but when the magnitude of that displacement is 1, the vibration displacement at the base end is approximately 10"2
is the value of On the other hand, the maximum displacement of the bending vibration is the width direction displacement of the vibrator at the tip of the tuning fork arm, and when that value is taken as 1, the vibration displacement at the base end is a value of about 118 to 10-4. This shows how large the vibration displacement at the base end of the torsional vibration in the tuning fork type crystal resonator is.

FIGS. 1, 2J2, and 6 show plan views of the tuning fork type crystal resonator. The base of a tuning fork crystal resonator is the part of the tuning fork crystal resonator excluding the two tuning fork arms.
At the base of a tuning fork type crystal resonator that undergoes torsional vibration, the largest displacement component is the displacement in the thickness direction of the resonator. The straight # that is the base end of the six shapes shown in Figures 1, 2, and 3.
+lAE, CD.

FIG. 4 shows the displacement U in the transducer thickness direction due to torsional vibration on the liF. This result was obtained by h-mai of the finite element method. However, the results shown in FIG. 4 show the characteristics when the torsional vibration is basic torsional vibration. Even when using higher-order vibrations of torsion, the results shown in Figure 4 and Ai4 i
Although there are some differences in terms of 4, qualitatively almost the same results can be obtained. In FIG. 4, 41 indicates the displacement on the straight line AB, 42 indicates the displacement on the straight line CD, and 43 indicates the displacement on the straight line EF. As is clear from Fig. 4, in the case of the tuning fork crystal resonator having the shape shown in Fig. 1, if a recess is not provided in the base, the widthwise ends of the base end, that is, near points A and B, Performs tilting vibration with large vibration displacement.

This tilting vibration at the base end is unique to a tuning fork crystal resonator that vibrates torsionally.

However, if a concave portion is provided in the base as shown in FIG. 2 or 3, the absolute value of displacement at the end of the base becomes small, and moreover, the swinging vibration disappears.

When a tuning fork type crystal lifter is supported at a base, if the displacement at the base is large, a phenomenon of vibration leakage occurs in which the vibration energy of the vibrator leaks through the support material. If the vibration leakage is large, it has the disadvantage that stable frequency temperature characteristics and frequency aging characteristics cannot be obtained. In this way, by providing a recess at the base of a tuning fork crystal resonator that utilizes torsional vibration and supporting it closer to the end of the base than the four parts, stable frequency temperature characteristics and frequency aging characteristics with less vibration 11 removal can be obtained. It has the characteristics of

By the way, a tuning fork type crystal resonator with four parts in the base as shown in Fig. 2 or 3 has weaker impact resistance than the shape shown in Fig. 1 without a concave part in the base. There is. That is, in order to strengthen the shock resistance of a tuning fork crystal resonator with a recessed portion in its base, it is necessary to find appropriate conditions other than the resonator.

<Object of the Invention> The present invention aims to improve the impact resistance of a tuning fork crystal resonator having a concave portion in its base, which is weak in impact resistance, and to provide a support structure that prevents the resonator from breaking due to impact caused by dropping. This is the purpose.

<Example> The present invention will be explained in detail below.

FIG. 5 is a side view showing a state in which a tuning fork type crystal resonator is sealed in a container. 51 is a tuning fork type crystal resonator, 52
56 represents a support material which also serves as an electrical lead, 56 represents a plug, and 54 represents a container. D is the diameter of the container and LC is the total length of the container. The current container for watch crystal units has a D of 1.
．． 5 to 2.0 +++m, and a TJ of between 5 and 6 is the mainstream. When a tuning fork type crystal resonator is enclosed in this container, it is desirable that the total length of the resonator is 4 songs or less. When producing a tuning fork crystal resonator using photolithography, if the resonator is thick, etching the crystal takes a very long time, making it unsuitable for mass production. Therefore, it is desirable that the thickness of the vibrator be 100 μm or more. Tuning fork crystal resonators, which have a thin resonator and a recessed portion at the base, have the disadvantage that they are very easily broken by impact.

When a tuning fork-type crystal camera having a concave portion at its base breaks due to a fall impact, the locations where the tuning fork crystal camera breaks are shown in FIGS. 6 and 7. FIG. 6 shows a tuning fork type crystal resonator in which a recess is provided at the end of the base, and FIG. 7 shows a recess in the middle of the base. 61 and 71 are crystal oscillators, 62 and 72 are supporting material broken lines 65, 64, 65, 75, 74.75 which also serve as electrical leads.
indicate the locations where the parts break due to impact. 63 and 75 indicate that the breakage occurs from the point closest to the tip of the tuning fork arm among the points of contact between the reed and the crystal. 64 and 74 indicate folding from the recess provided at the base. 65 and 15
indicates that it breaks from the fork part at the base of the tuning fork arm. The mechanism of breakage due to impact is different depending on whether the arm breaks at the fork, which is the base of the arm, or at the base.

Figures 8 and 9 show the mechanism by which the vibrator breaks due to a falling bullet.
Let's think about it in terms of a diagram. FIG. 8 is a side view showing a state in which a fork-shaped crystal resonator having four parts provided at the base end is sealed in a container, and FIG. 9 is a plan view thereof. 81
, 91 is a tuning fork type crystal oscillator, 82, 92 is a fork part, 83 is the starting position of the four parts at the base, 84 and 95 are supporting materials based on electrical leads, 85 and 94 are plugs, 86 and 95 represents a container. The direction of fall in which the vibrator is most likely to break, that is, the impact force applied to the dragon excitation is greatest, is in the direction of arrow 87 in FIG. 8, and in the direction of arrow 87 in FIG.
- This is the case when the object falls perpendicular to the plane. At the moment when it falls and receives an impact, the tip of the tuning fork arm first moves in the direction of arrow 8 due to inertia.
Deflect in direction 8. At this time, a strong upward impact force acts on the point 89 closest to the tip of the tuning fork arm and the point 83, 96 where the recess begins among the points of contact between the reed and the vibrator. As a result, broken lines 65, 64 . It is bent at the broken line 73°74 shown in FIG. The impact force transmitted from the lead to the vibrator is stronger as the bending of the leads 84 and 93 due to the impact is smaller. If the deflection of the lead is large, the impact force transmitted from the lead to the vibrator will be weakened, causing the failure shown in Figure 6, i.
No bending occurs along the springs 63 and 64 or the broken lines 75 and 74 shown in FIG.

FIG. 10 is a side view of a tuning fork crystal resonator supported by a lead, showing how the lead bends due to impact. 1
01 is a tuning fork crystal oscillator, 102 is a cross section, 103 is a starting point of a recess provided at the base, 104 is a support material that also serves as an electrical lead, and 105 is a plug. In FIG. 10, δ and L represent the deflection of the lead due to collision. δL can be approximately expressed by the following equation, where AL is the length of the lead between the base end of the vibrator and the plug 1, tr is the thickness of the lead, and E is the Young's modulus of the lead.

δI, = 4 L' / (K t L") Thus,
In order to weaken the impact force of the vibrator, when the abrasive quality of the reed is constant, the length tL of the reed may be increased or the thickness t of the reed may be decreased.

Reed generally has a Young's modulus E of 14,0009/,
Kovar J is used. When a tuning fork-shaped crystal resonator with a four-part base supported by Kovar with a thickness of 200 μm or more is dropped from 11n on a concrete board, it will not break at the dashed lines 63, 64, 73°74, etc. shown in Figure 6. I understand. This is because when the thickness of the lead is 200 μm or more, the deflection of the lead due to impact becomes small, and the impact force applied from the lead to the vibrator during locking becomes very large.

If the thickness of the vibrator is 100 μm or less, the impact resistance will be weakened even though the impact force transmitted from the lead to the vibrator is the same.

On the other hand, in order to weaken the impact force transmitted from the lead to the vibrator, it is necessary to increase the deflection δL of the lead at the time of impact. To achieve this, the thickness of the lead may be reduced, and the distance t1 between the base end of the vibrator and the plug may be increased.

Therefore, the thickness of the lead may be set to 200 μm or less, and LL may be made long. By the way, as a result of the deflection of the IJ-board due to the impact, the vibrator is also displaced from its resting position. FIG. 10 shows the displacement δR of the tip of the tuning fork arm from its rest position due to the impact. If this δR is too large, the tip of the tuning fork arm collides with the inner wall of the container, and a large #i impact force is applied to the fork.

As a result, the tuning fork type crystal resonator is broken at the broken lines shown at 65 in FIG. 6 and 75 in FIG.

For this reason, as mentioned above, in order for the vibrator not to break at the base, the lead must bend to some extent upon impact.
・) On the other hand, in gardens where the vibrator does not break at the forks, it is a problem if the lead is too bent.

In order to prevent the lead from bending too much due to impact, the distance between the base end of the vibrator and the plug needs to be smaller than a certain value. A tuning fork-shaped crystal resonator with a length of 4 and a thickness of 50 μm with a recess at the base is supported by a 100 μm thick Kovar reed and sealed in a container with a diameter of 2.
A drop experiment was conducted from 1 m above the board. As a result, it was found that when the distance LL between the base end of the pendulum and the plug was 500 μm or more, the tip of the tuning fork arm collided with the container due to the impact, causing the fork portion to break.

FIG. 11 shows an embodiment of the tuning fork type crystal resonator of the present invention. Reference numeral 111 indicates a tuning fork type crystal resonator having a recessed portion at its base, reference numeral 112 indicates a support material which also serves as an electrical lead, and reference numeral 113 indicates a plug.

Two supporting members 112, which also serve as electrical leads, are supported on the same plane at the base of the tuning fork type crystal resonator.

The total length of the iK dispersion type crystal resonator is 4 mm or less, and the thickness is 100 μm or less. Young's modulus of lead 112 is 10
The lead has a value of 000 to 15000/-, and the lead thickness is 200 μm or less. The distance LL between the base end of the vibrator and the plug is 500 μm or less. Young's modulus is 100
When the value is in the range of 47 mA from 00 to 15000, the above discussion is almost applicable. Further, specific examples of the present invention are shown below.

In Figure 11, the total length of the tuning fork crystal resonator is 3.3
mm, the length of the tuning fork arm Za is 1 key, and the length of the base zb is 2
．． 3 m+n, the length of the four parts is tCil''i0.6, the maximum width W of the vibrator is 1 tone, the amount of cut W of the concave part of the base is 0,
2 am, and the thickness of the oscillator is approximately 5571 m. I.J.
The Young's modulus of -do is about 14,000 and Kovar of 4'/-.
The thickness of the lead was 125% m, and the distance between the base end of the vibrator and the plug was 300 μm. The supporting structure of the tuning fork type crystal resonator with a recessed part at the base of the present invention has excellent shock resistance, and will not break even if dropped from 1 m on a concrete plate, and the frequency of the resonator will shift before and after the drop. There are also very few.

By the way, if the cut amount W of the four portions provided in the base shown in FIG. 11 is too large, a structure that is strong against impact cannot be obtained only by the lead conditions. It is desirable that the sum of the incisions at the two locations, 2W, is less than half the maximum width W of the vibrator. That is,
The tuning fork type crystal resonator of the present invention needs to satisfy the following relationship.

2 w / W ≦05 This condition also applies to the tuning fork type crystal resonator having the shape shown in FIG. 5, that is, a recessed portion is provided not at the base end of the base portion but at a position in the middle of the base portion.

<Effects of the Invention> As explained above in detail, the support structure of the tuning fork type crystal resonator of the present invention has excellent impact resistance and has excellent characteristics that keep the characteristics of the resonator stable.

[Brief explanation of drawings]

Figures 1, 2, and 3 are plan views of tuning fork crystal resonators;
FIG. 4 is a graph showing the displacement in the thickness direction of the vibrator at the base end when the tuning fork type crystal vibrator having the shapes shown in FIGS. 1, 2, and 3 torsionally vibrates, and FIG. Figures 6 and 7, which are side views showing a tuning fork type crystal resonator sealed in a container, show the points where a tuning fork type crystal resonator with a concave portion at its base breaks due to impact. A plan view of a tuning fork type crystal vibrator, FIG. 8 is a side view showing a state in which a tuning fork type crystal vibrator with a recess at the base end is inserted into a container, and FIG. Fig. 101d is a plan view showing a tuning fork type crystal resonator sealed in a container;
FIG. 1 is a plan view of a support structure for a tuning fork crystal resonator according to an embodiment of the present invention. 111,...Tuning fork crystal resonator 112...Lead 113...Plug L...Full length W of the vibrator...Amount of cut of the recess tL...Distance between the base end of the vibrator and the plug More than the lead distance Fig. 2 Fig. 3 +=<+ E F -> Position of the base of the weight Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 Fig. H mouth

Claims (2)

[Claims] (1) A tuning fork type crystal resonator with a recessed portion at the base having a total length of less than 100 μm and a thickness of less than 100 μm has a Young's modulus of 10,000 to 1 on the same plane of the base.
The vibrator is supported by two supporting materials that also serve as electrical leads having a value in the range of 5000 to 9/2, the distance between the base end and the plug is 400 μm or less, and the lead thickness is 200 μm or less. A support structure for a tuning fork crystal resonator, characterized in that: (2) A tuning fork type according to claim 1, wherein the cut amount W of the recess provided in the base satisfies the condition 2w/W≦0.5 with respect to the maximum width W of the vibrator. Support structure for crystal oscillator.