JPS644369B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a crystal resonator.

The present invention aims to increase the Q value of a coupled vibration type crystal resonator that should improve the resonant frequency temperature characteristics of a crystal resonator having a relatively low resonant frequency, effectively suppress vibration leakage, and improve mechanical properties such as impact resistance. This improves the physical properties of the material.

As electronic clocks become more precise, attention is being focused on increasing the precision of the crystal oscillators that serve as their time standard sources.

Currently, the mainstream of crystal resonators used in wristwatches, for example, is a tuning fork type crystal resonator with bending vibration, which has an oscillation frequency of about 32 KHz, due to its low current consumption characteristics. However, the frequency temperature characteristics of this bending vibration mode tuning fork type crystal resonator vary by 15 to 20 ppm between 0°C and 20°C, making it difficult to use as a time standard source for high-precision crystal resonators, which is currently required. It's hard to say. On the other hand, as an existing high-precision crystal oscillator, there is an AT-cut crystal oscillator that vibrates through the thickness, and although it draws a fairly good cubic curve frequency-temperature characteristic, it not only consumes a high current but also has a size problem. big.

In this way, conventional crystal oscillators had trade-offs, but in order to improve the precision of electronic watches, it was necessary to improve both the frequency-temperature characteristics, which were trade-offs, and the current consumption due to the reduction of the oscillation frequency. It is necessary to realize this. The tuning fork type crystal resonator that utilizes the combination of the bending vibration mode and the torsional vibration mode described in the present invention achieves both the improvement of frequency temperature characteristics for the above-mentioned high precision and the reduction of current consumption. The characteristics show a cubic curve as shown in Figure 1, and the example shown in Figure 1 has almost flat temperature characteristics in the temperature range of 0℃ to 40℃, with bending vibration mode and torsional vibration mode. There are various types of vibrations, including those that utilize higher-order vibrations ranging from main vibration to secondary vibration.

Hereinafter, a tuning fork type crystal resonator that improves frequency-temperature characteristics by utilizing the combination of two vibration modes, a bending vibration mode and a swing vibration mode, will be referred to as a coupled vibration crystal resonator.

A crystal resonator generally has a Q value, which indicates its typical characteristics. In general, it is high because quartz is a highly elastic material.

However, it is impossible to use a crystal oscillator as a stand-alone unit; it can be attached to a holding member, an electrode extraction member, etc., or stored in various storage cases to form a quartz crystal unit. This allows it to be used as a wristwatch or other time standard source for the first time.

The same holds true for other static properties and mechanical properties such as impact resistance, and it is important not only to design the crystal resonator alone, but also to design the holding structure that holds it.

The object of the present invention is to connect the lead wire of a hermetic seal and the tip of this lead wire. By joining the base of the coupled vibrating crystal unit to the tip of the thin plate-shaped holding member bent into an L shape, it is possible to improve the Q value of the crystal unit as described above and the static characteristics such as suppressing vibration leakage. It is.

In addition, another object of the present invention is to use, as a holding member,
By using a hermetic seal lead wire and an L-shaped thin plate-like holding member, the impact resistance of the crystal unit can be improved in each impact direction.

Still another object of the present invention is to downsize a coupled oscillating crystal resonator as a crystal unit by using the lead wire of the hermetic seal and the L-shaped thin plate material as a holding member.

The principle of the present invention will be specifically explained below.

FIG. 2 shows the structure of a coupled vibration crystal resonator according to the present invention. In Figure 2, 1 is a single coupled vibrating crystal resonator, 2 is a hermetic seal, 3 is a lead wire of the hermetic seal, 4 is an L-shaped thin plate, and 20 is a holding part for the single coupled vibrating crystal resonator. This shows that.

Further, FIG. 3 shows a developed view of the L-shaped thin plate member shown in FIG. 2, and the dotted line indicates the bending position.

Further, FIG. 4 shows a completed view of the L-shaped thin plate member shown in FIG. 2, and 5 in FIG.
is the joint part of the hermetic seal to the lead wire,
Reference numeral 6 indicates a joint portion to the base of the coupled vibration crystal unit. Further, 21 is a spring plate-like portion.

Further, FIGS. 5 and 6 show other examples of L-shaped thin plate members, in which 7 and 9 are the joint parts of the hermetic seal to the lead wire, and 8 and 10 are the joint parts of the hermetic seal to the lead wire. This shows the joint part to the base of the crystal unit.

The Q value of a crystal unit is closely related to other vibration characteristics of the crystal unit such as vibration leakage, and in particular, as in the case of the coupled vibration crystal resonator described in the present invention, the frequency temperature characteristic is its characteristic characteristic. If the vibration leakage is large, the important frequency-temperature characteristics may be disturbed.

In general, the means to improve the Q value and vibration characteristics such as vibration leakage as a crystal unit are as follows.
There are two methods: One is to prevent vibration leakage and increase the Q value by devising the holding member, and the other is by devising the crystal resonator itself so that it is not affected by the holding etc. It is to do so.

The present invention belongs to the former of the above two methods, and specifically, the propagation of the vibration displacement of the holding part of the crystal resonator to the holding member is determined from the perspective of vibration mechanics by determining the shape and size of the holding member. As described below, by appropriately selecting the vibration of the crystal unit, it is possible to prevent the vibration of the crystal unit from leaking into the storage case, etc., and reduce the mass of the holding member, storage case, etc. This is based on the viewpoint of minimizing the influence of various external forces applied to the crystal unit on the vibration mode of the crystal resonator itself, suppressing vibration leakage and ensuring that the crystal unit does not vibrate sufficiently. If it is possible to confine it inside the crystal unit, the Q value of the crystal unit will also improve.

Next, the principle of improving the static characteristics such as the Q value and vibration leakage in the holding structure of the coupled vibrating crystal resonator according to the present invention will be theoretically explained.

FIG. 7 shows the structure of the coupled vibration crystal resonator shown in FIG. 2 as a vibrational dynamic model.
In Fig. 7, 11 indicates the spring component of the holding member, 12 indicates the mass component of the holding member, 13 indicates the vibration displacement of the base of the crystal unit, and 14 indicates the mass component of the hermetic seal, storage case, etc. It is shown as follows. 13 can be regarded as an excitation force in terms of vibration mechanics, and the improvements in the Q value, vibration leakage, etc. mentioned above can be shown by how small the vibration displacement of the mass component 14 is with respect to the excitation force of 13. can.
Assuming that the waveform and absolute value of the excitation force shown in FIG. It's different.

FIG. 8 shows this relationship, with the horizontal axis showing the value of the spring component of the holding member, and the vertical axis showing the value of the displacement y ₁ of the mass component in FIG. 7 and 14.

As shown in FIG _. 8, there are multiple values of the spring component of the holding member that make the displacement value y ₁ of the mass component in FIG. The value of the spring component is determined by the material, dimensions, shape, processing, etc. of the holding member, and several combinations are available for these. becomes effective.

In the coupled vibration crystal resonator according to the present invention shown in FIG. 2, it can be said that the shape of the holding member makes it easy to minimize the value of _y1 . This is because the holding member is developed mainly at right angles to the surface of the tuning fork crystal resonator, which not only facilitates the supply and reception of the base vibration displacement component of the coupled vibration crystal resonator, but also combines this effect. This is because the L-shaped thin plate holding member connected to the vibrating crystal unit base holding part is closed from a high position because it is made of a thin, flexible material.

In addition, mechanical properties such as impact resistance as a crystal unit are one of the most realistic and important environmental characteristics when the crystal unit is actually used as a wristwatch or other component. is possible,
The holding structure of the crystal resonator is an important factor.

There are two phenomena that affect shock resistance as a crystal unit: cessation of oscillation and change in oscillation frequency.
Alternatively, the main cause may be destruction of the holding part, and the main cause of the change in oscillation frequency may be partial chipping of the crystal resonator or slight loosening of the holding part.

As a direct cause of the two main causes of oscillation stop and the two main causes of oscillation frequency change mentioned above, there is a collision of the crystal resonator itself with the storage case when an impact is applied to the crystal unit. Presence or absence can also be cited as the most important factor. In other words, if the crystal oscillator itself collides with the inner wall of the storage case, it is likely that the crystal oscillator collided part will be partially chipped, or the holding part will be damaged due to the lever principle. Although this is only a change in the oscillation frequency, if this is extreme, the oscillation may stop due to destruction of the crystal resonator itself or destruction of the holding part.

Therefore, the most effective means of improving the shock resistance of a crystal resonator is to avoid the crystal resonator itself colliding with the inner wall of the storage case when a shock is applied to the crystal unit. I can do it.

In other words, in order to improve the shock resistance of a crystal resonator, it is necessary to minimize the vibration of the crystal resonator itself when an impact is applied to the crystal unit.

In the case of a coupled oscillating crystal resonator as used in the present invention, since a torsional component is included as a coupled oscillation component, measures to improve the Q value and principles of vibration leakage countermeasures as described above are required, and some kind of retention structure devising is required. Although necessary, simply improving the Q value and suppressing vibration leakage to some extent can be achieved by using a flexible holding member as schematically shown in FIG. In FIG. 9, 15 is a hermetic seal, 16 is a crystal resonator, and 17 is a holding member. However, if the holding member is simply flexible, the vibration of the crystal resonator will generally increase when a mechanical shock is applied to the crystal unit. Regarding the holding structure of a coupled oscillating crystal resonator, it is better for the holding member to be flexible in terms of static characteristics such as Q value and vibration leakage;
Regarding dynamic characteristics such as impact resistance, there arises a contradictory need for the holding member to be rigid.

The coupled vibration crystal resonator according to the present invention answers the above-mentioned contradictory needs, and the solution to the need for static characteristics on the one hand is as described above.

Here, FIG. 10 is shown to explain measures for improving impact resistance in the present invention.

In FIG. 10, reference numeral 18 indicates a single coupled vibration crystal resonator, and reference numeral 19 indicates a holding member. Also, to show the direction in which the impact is applied, the X and Z axes are shown in FIG.

In FIG. 10, when an impact is applied from the Z-axis direction, the holding member 19 holds the coupled vibration crystal unit 18 from both sides, so the vibration of the crystal unit 19 due to the impact is comparatively small. Although the impact is small, when a shock is applied from the X-axis direction, the vibration of the crystal unit 19 is generally
Since the rigidity against the impact force in the X-axis direction is too small, it becomes very large.

The coupled oscillating crystal oscillator according to the present invention shown in FIG. 2 increases the rigidity of the holding member against the impact force in the X-axis direction shown in FIG. The rigid thickness of the thin plate material of the holding member 4 in FIG. 2 and the vertical direction are the X of the impact in FIG. 10.
This is because it is aligned with the axial direction.

Furthermore, the coupled vibrating crystal oscillator according to the present invention shown in FIG. Since the holding member shown in FIG. 2 and 3, which is highly rigid in both the X-axis and Z-axis directions, is used, the coupled vibrating crystal unit as a crystal unit according to the present invention has excellent impact resistance in each impact direction. ing.

Further, the coupled vibration crystal resonator according to the present invention is excellent in miniaturization as a crystal unit. That is, in the case of the holding method as shown in FIG. 10, the dimension in the Z-axis direction in FIG.
As is clear from the figure, for the holding member in FIG. 2, 4, only the thickness component of the thin plate material contributes to the dimension in the Z-axis direction in FIG.
Since the holding members 3 and 4 are separate, the holding members 3 and 4
Because it is possible to minimize the gap between
Overall, the dimension in the Z-axis direction in FIG. 10 can be made considerably smaller, and therefore the crystal unit can be made smaller.

As described above, the coupled vibration crystal resonator of the present invention has various advantages such as improved static characteristics as a crystal unit, improved impact resistance, and further reduction in size.

Note that the present invention includes a coupled tuning fork type vibrating crystal unit made from a quartz plate with a thickness of 500 μm or less by the ring graphi manufacturing method, etc. without departing from the basic idea of the present invention. Of course, it also includes those with modifications.

[Brief explanation of the drawing]

Figure 1 ~ Frequency temperature characteristics of a coupled oscillating crystal resonator. Fig. 2 - Structure of the coupled oscillating crystal resonator according to the present invention with the storage case removed. FIG. 3 is a developed view of the L-shaped thin plate member shown in FIGS. 3 to 4 of FIG. 2; FIG. 4 is a completed view of the L-shaped thin plate member shown in 4 of FIG. 2;
FIG. 5 - Other examples of L-shaped thin plate members. Figure 6~L
Still other examples of letter-shaped thin plates. Figure 7 shows the structure of a coupled oscillating crystal resonator as a vibrational mechanics model. In the dynamic models shown in FIGS. 8 to 7, the value of the spring component of the holding member 11 and the excitation force 13
This shows the relationship between the displacement y ₁ of the mass component 14 and the value of the mass component 14. Figure 9 ~ In a coupled oscillating crystal oscillator, Q
A general structural model diagram for achieving high levels of static characteristics such as vibration and leakage characteristics. FIG. 10 - A diagram for explaining the mechanism regarding impact resistance of a coupled vibration crystal resonator. 1... Coupled vibration crystal unit, 2... Hermetic seal, 3... Lead wire of hermetic seal,
4... L-shaped thin plate-shaped holding member, 20... Holding part for a single coupled vibration crystal oscillator, 5, 7, 9... Joint part of the hermetic seal of the L-shaped thin plate-shaped holding member to the lead wire, 6, 8, 10...Joining portion of L-shaped thin plate-like holding member to base of coupled vibrating crystal unit, 11
...Spring component of the holding member in the vibration mechanics model of the coupled vibrating crystal oscillator, 12...Mass component (holding member) as above, 13...Vibration displacement at the base of the vibrator unit in the vibration mechanics model of the coupled vibration crystal oscillator. (Fundamental force on the mechanical model), 14... Mass component due to hermetic seal and storage case in the vibration mechanical model of the coupled oscillating crystal oscillator, 15... Hermetic seal, 16, 18... Single coupled oscillating crystal oscillator , 17, 19... Holding member.

Claims (1)

[Claims] 1. In a support structure for a coupled tuning fork type crystal resonator in which frequency temperature characteristics are adjusted by elastically combining torsional vibration with bending vibration, the support structure penetrates through the hermetic seal 2 and the main body of each tuning fork type crystal resonator. It consists of two lead wires 3 disposed facing the surface, and a thin plate-shaped holding member 4, one end of which is fixed to the lead wire and the other end fixed to the base of the tuning fork crystal resonator. The vibrator has a base close to the hermetic seal and is arranged with a gap therebetween, and the thin plate-shaped holding member has a plate surface between the lead wire and the tuning fork type crystal resonator. Spring plate-shaped portion 21 arranged parallel to the main surface
a first joint part 6 whose end face is bent into an L-shape and joined to the base of the tuning fork crystal resonator at one end of the spring plate-like part, and an L-shape at the other end of the spring plate-like part. and a second joint part 5 whose bent plate surface is joined to the lead wire, and the second joint part is arranged closer to the fork part of the tuning fork type crystal resonator with respect to the first joint part. A support structure for a coupled tuning fork type crystal resonator, characterized in that: