JPS587694Y2 - Support device for tuning fork-shaped piezoelectric vibrator - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a support device for a tuning fork-shaped piezoelectric vibrator.

This type of technology has improved significantly in recent years, especially in the field of tuning fork-shaped ice crystal oscillators used as reference oscillators for wristwatches.As shown in FIG. is arranged, and the end surface of the base 2 where the extraction electrode 15 is provided is fixed to the support 4 using a conductive adhesive containing silver or a fixing agent 3 by soldering.

This type of fixing technology has excellent mechanical strength, but when the vibrator is housed in a sealed case,
The vibration waves of the vibrator are transmitted through the adhesive 3 to the support 4 and the sealed case, and acoustic leakage to the sealed case occurs, so the resonance sharpness Q and series resonance resistance value CI of the vibrator are reduced due to the influence of acoustic loss. was forced to deteriorate.

On the other hand, if manufactured using such a fixing technique, the lead wire 6 can be used for electrical connection between the external lead wire 5 and the lead electrode 15.
must be soldered.

Therefore, as the piezoelectric vibrator becomes smaller, the manufacturing process becomes more complicated and reliability decreases.

As a result of extensive research into these problems, the present invention has revealed that the cause of the acoustic leak mentioned above is largely influenced by the adhesive itself that fixes the piezoelectric material and the support, and that the lead wire 6 The present invention was developed based on the selection of the most suitable adhesive.

In the present invention, an excitation electrode for flexural vibration is disposed on the leg of a tuning fork-shaped piezoelectric body, and an extraction electrode drawn out from the excitation electrode is disposed on the base of the tuning fork-shaped piezoelectric body, and the base is fixed to a support. In the tuning fork piezoelectric vibrator, a rubber adhesive is applied to the end surface of the base to fix the tuning fork piezoelectric body and the support, and to bring the extraction electrode into contact with the support. This is a support structure for a tuning fork-shaped piezoelectric vibrator, which is characterized in that a rubber conductive adhesive is applied to the top surface of the vibrator.

Here, the tuning fork-shaped piezoelectric material is, for example, ice crystal, lithium tantalate, etc. Refers to a piezoelectric material such as lithium niobate and piezoelectric ceramic molded into a tuning fork shape. Rubber adhesives include, for example, natural rubber, polyisoprene rubber, polybutadiene rubber, neoprene rubber, etc., which have electrical insulation properties. It refers to rubber adhesives such as styrene-butadiene rubber, nitrile rubber, silicone rubber, etc., as well as elastomer comerics (trade name of Fujikura Chemical Co., Ltd.) that have conductive properties. Refers to rubber conductive adhesives such as elastomers and comerics.

The base (or bottom plate) used in the tuning-fork piezoelectric vibrator of the present invention is suitable for the press-fitting method as shown in Figures 2.3 and 4, and for the cold welding method. For example, those shown in FIGS. 9 and 10.

The symbol 5 in each figure is an external lead wire that is electrically connected to the excitation electrode of the tuning fork-shaped piezoelectric vibrator.
Although it has a cylindrical shape, its longitudinal cross section may be rectangular.

The insulator 8 is made of a glass material or the like, and is enclosed in the circular tube 9 to fix the external lead wire 5.

In figures 3.4 and 9, respectively, support 10.1
1. and 12 have a larger area for holding the tuning fork voltage-resistant electric body than the support 51 shown in FIG. 2 (the part that is integrated with the external lead wire and projects from the insulator 8);
The support 13 shown in FIG. 10 is suitable when the main surface (the surface larger than other surfaces) of the piezoelectric body is installed parallel to the plane of the support, and the contact area with the tuning fork piezoelectric body is Both are connected to the external leader line 5 or have an integral structure.

Next, embodiments of the present invention will be described with illustrations.

5.6, 7, 8.11 and 12 are examples in the case of a tuning fork-shaped piezoelectric vibrator, and the electrode arrangement is as shown in FIG.
6 and 11, two divided electrodes 7 □ 1, 7 □ 1 and 7 □ 2, 7 □ 2,
In addition, 7□3, 7□3 and 7□4, 7□4 are excitation electrodes for bending vibration, and in Figs. 731.
734.743 and 744, and 73□, 733.
741 and 742 are excitation electrodes for bending vibration.

In any case, what is effective as the excitation electrode is an electrode extending from the root 14 of the tuning fork piezoelectric body to a length l'.

The length l' of this excitation electrode is from 0.4 to the total length l of the leg part 1.
It has 0.6 times the length.

The base shown in FIG. 2 is used in FIGS. 5 and 7, the one shown in FIG. 3 is used in FIGS. 6 and 8, and the one shown in FIG. 10 is used in FIGS. 11 and 12, respectively.

In FIGS. 5 and 7, the tuning fork piezoelectric body is constructed such that the bottom surface of the base 2 is in contact with the insulator 8 as shown in the drawings, and the end surfaces with the two extraction electrodes 15 are inserted between the supports 51, respectively. 6 and 7, the bottom surface of the base 2 is brought into contact with the insulator 8 as shown, and the end surfaces with the two extraction electrodes 15 are inserted between the supports 10, and 11. In Figure 12, two extraction electrodes 1 are connected as shown in the figure.
The end faces with 5 each rest on a support 13.

A rubber adhesive 16 is applied between the end surface of the tuning fork-shaped piezoelectric vibrator provided with the extraction electrode 15 and the supports 51, 10 and 13 shown in each figure to fix the tuning fork shape to each support. It's forcing me.

Then, a rubber conductive adhesive 17 is applied so that the lead electrode 15 of the piezoelectric vibrator comes into contact with the supports 51, 10 and 13 shown in each figure, and the above-mentioned excitation electrode and external lead wire 5 are electrically connected. Connect to.

In addition, in FIGS. 11 and 12, 1 is a perspective view of a tuning fork piezoelectric body installed on a base and coated with the adhesive 16, 17 of the present invention, and 2 is a perspective view of only the piezoelectric body on which electrodes are arranged. A perspective view with the back side facing up, and a detailed view of the application of adhesive 16, 17 is shown in Figure 3 in both Figures 11 and 12.

In the support device for a tuning fork piezoelectric vibrator constructed in this manner, since a rubber adhesive is interposed between the tuning fork piezoelectric body and the support body, acoustic leakage can be prevented.

A tuning fork-shaped piezoelectric vibrator is housed in a sealed case and a load of about 100 g is applied to the case, which is normally done by those skilled in the art.
According to a so-called clamp test that measures the resonant frequency fluctuation before and after applying the load, the conventionally used conductive adhesive or solder had a resonant frequency of about 100 ppm. In other words, it was 2.3 ppm or less, which confirmed its excellent ability to prevent acoustic leakage.

By preventing acoustic leakage, the characteristics (resonance sharpness Q, series resonance resistance value CI, etc.) of the tuning fork piezoelectric body itself can be maintained.

On the other hand, since the lead wire connection process is omitted in terms of manufacturing, work efficiency can be dramatically improved, and reliability can also be improved.

In addition, as for the electrode arrangement, the length l' of the excitation electrode is
Since it is 0.4 to 0.6 times the total length l, it has the effect of suppressing spurious waves caused by higher-order modes other than the fundamental wave.

However, if this spurious can be ignored, the length l' of the excitation electrode can be chosen freely.

[Brief explanation of drawings]

Figure 1 shows a support device for a tuning fork crystal resonator according to the prior art.
Figures 2.3, 4.9 and 10 are the base (or bottom plate) used in the present invention, and Figures 5.6, 7, 8.11 and 12 are of the supporting device for the tuning fork-shaped piezoelectric vibrator of the present invention. It is a figure showing an example. 51.10,11,12.13...Support, 1
5... Extraction electrode, 16... Rubber adhesive, 17... Rubber conductive adhesive.

Claims (1)

[Scope of utility model registration request] A tuning-fork-shaped piezoelectric body in which an excitation electrode for flexural vibration is disposed on the leg of a tuning-fork-shaped piezoelectric body, an extraction electrode drawn out from the excitation electrode is disposed on the base of the tuning-fork-shaped piezoelectric body, and the base is fixed to a support. In the vibrator, a rubber adhesive is applied to the end surface of the base to fix the tuning fork-shaped piezoelectric body and the support, and a rubber conductive adhesive is applied to the end surface of the base so as to make the tuning fork-shaped piezoelectric body and the support adhere. A supporting device for a tuning fork-shaped piezoelectric vibrator, characterized in that an adhesive is applied.