JPS6117169B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a holding structure for a thickness-shear piezoelectric vibrator that has excellent impact resistance and is suitable for miniaturization.

Conventionally, various configurations have been implemented as holding structures for thickness-shear piezoelectric resonators such as AT plate crystal resonators. However, it has been difficult to create a holding structure with good impact resistance in extremely small vibrators for watches, especially wristwatches, which use the vibration frequency of this type of vibrator as a time reference. Furthermore, in such a vibrator, it is difficult to equalize the amount of adhesive or solder used to securely hold the vibrator element to the holding member, the hardness of the support, etc. It has been considered difficult to avoid variations in the electrical characteristics of resonators. Therefore, there has been a desire for a vibrator that has excellent impact resistance, uniform electrical characteristics, and a holding structure suitable for miniaturization.

As a method for solving this problem, the present invention holds the edges of the vibrator element using a thermofusible resin that is an elastic body and has electrical insulation properties.

Here, consider the displacement distribution of thickness shear vibration.
For example, in the case of a crystal AT plate thickness shear resonator,
The displacement direction is parallel to the X-axis direction of the crystal, and the displacement distribution has a half-sine wave shape with a maximum at the center of the electrode. Furthermore, the displacement distribution in the Z'-axis direction becomes almost flat at the center of the electrode, and rapidly decreases exponentially at both ends. FIG. 1a is a perspective view showing an example of such an AT plate thickness shear vibrator, in which 1 is a vibrator element, 2 is an excitation electrode, and 3 is an extraction electrode.
FIGS. 1b and 1c are diagrams showing displacement distributions in the X direction and Z' direction, respectively.

As is clear from these figures, the smallest displacement is at each corner 1a4 of the crystal blank, and if these corners 1a are held and fixed, the effect of holding on vibration will be minimized. is expected.

Furthermore, in order to form a vibrator, it is necessary to ensure electrical continuity between the electrode portion formed on the surface of the vibrator element and the outer lead of the package.
FIG. 2 is a perspective view showing an example of a thickness-shear vibrator with electrodes drawn out by wire bonding, in which excitation electrodes 5 and lead-out electrodes 6 protruding to the sides are formed on the surface of the vibrator element 4. A lead-out wire 7 is bonded to this lead-out electrode 6. In this way, good electrical continuity can be obtained between the wire 7 and the excitation electrode 5, with little variation in characteristics.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the assembled perspective view shown in FIG. In the figure, 11 is a crystal cut at a predetermined angle to the crystal axis.
For example, it is a vibrator element of an AT plate. And 1
2 is an electrode formed on the plate surface of this vibrator element 11;
Reference numeral 13 denotes a lead-out electrode extending from the electrode 12 to the end face of the vibrator element 11;
A lead wire 14 is attached to the terminal by wire bonding. Furthermore, 15 and 16 correspond to the corners 15a and 16a of the vibrator element piece 11.
These are a pair of holding members made of an elastic body and an electrically insulating thermofusible resin, for example, vinyl chloride resin or Aflon resin (trade name, Asahi Kasei). The pair of holding members 15 and 16 are connected to the vibrator element 1.
Pressure is applied while pinching the corner portions 11a of both plate surfaces of 1,
The corner portion 11a of this vibrator element piece 11 is heated.
are held in between and fused together.

With such a configuration, the vibrator element piece 11 can be held with an extremely simple configuration, work efficiency during manufacturing can be improved, and miniaturization can be easily achieved. Furthermore, since the corners of the vibrator with the least displacement are maintained, the electrical characteristics do not deteriorate, and a thickness-shear piezoelectric vibrator with excellent vibration resistance and impact resistance can be obtained.

Furthermore, in the present invention, as shown in FIG. 4, for example, the lead wire 14 is
Since it is possible to fix in any direction when fusing the wires, it is possible to seal them in a package of a desired shape without shorting even two lead wires that are close to each other.

Note that by using a synthetic resin with excellent elasticity at room temperature for the holding member, extremely excellent vibration resistance and impact resistance can be obtained.

As described in detail above, the present invention has good electrical characteristics because the piezoelectric vibrator is held by sandwiching the corner portion between a pair of holding members made of heat-welded thermofusible synthetic resin. Therefore, it is possible to provide a holding structure for a thickness-shear piezoelectric vibrator that does not require particularly precise machining, has high productivity, and has excellent vibration resistance and impact resistance.

[Brief explanation of the drawing]

FIG. 1a is a perspective view showing an example of an AT plate thickness-shear oscillator, FIGS. 1b and c are views showing the displacement distribution of the above-mentioned oscillator, and FIG. 2 is a perspective view showing an example of a thickness-shear oscillator. FIG. 3 is an assembled perspective view showing one embodiment of the invention, and FIG. 4 is a perspective view showing another embodiment of the invention. 11... Vibrator element piece, 12... Electrode, 14...
Lead wires, 15, 16...holding members.

Claims (1)

[Claims] 1 Extending the electrode formed on the plate surface to the end surface via the lead electrode, leaving a portion corresponding to the lead wire attached to the lead wire and the corner of the vibrator element, the lead wire attached to the lead electrode. and a pair of holding members made of an elastic body and an insulating thermofusible resin with a central portion hollowed out, and the corners of the vibrator element and the lead wire are held between the pair of holding members. A holding structure for a thickness-slip piezoelectric vibrator, which is characterized by being held in place, heated, and fused.