JPS6141215A - Crystal resonator - Google Patents

Abstract

PURPOSE:To improve the shock resistance and to prevent the deterioration of characteristics due to the secular change, by forming the electrode plates to a recess surface adhered to both sides of a crystal plate and having an electrode film formed on the counter surface. CONSTITUTION:A pair of electrode plate 2 are formed with adhesion to both sides of a crystal plate 1. The counter surface of each plate 2 to the plate 1 is formed into a recess surface 21 containing an electrode film 22. In this case, the total thickness of a resonator can be reduced down to about 0.25mm.. This increases the mechanical strength of the resonator. Furthermore the film 22 is led outside to secure the thickness-shear vibrations. Then the vibrations of the plate 1 are never disturbed since the film 22 is set opposite to the plate 1 via a gap. In addition, the resonator is free from any effect of the secular change due to oxidation of the electrode, etc.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention has good impact resistance, workability, and excellent aging characteristics. It relates to a crystal resonator with a relatively high resonant frequency.

[Technical background of the invention]

Conventionally, for example, an AT-cut thick-beam crystal resonator uses a disc-shaped crystal piece cut at a predetermined angle with respect to the crystal axis of the crystal. Gold (Au) is placed in the center of this crystal piece.
, silver (A)), aluminum (Al), etc., is formed by vapor deposition or the like. Furthermore, both ends of the crystal piece are inserted into a slit formed at the tip of a holding lead terminal, the electrode is led out here, and thickness-beam vibration is excited through this lead terminal. .

[Background technology points]

However, in such a device, the oscillation frequency tends to fluctuate due to distortion caused by stress when inserting the crystal piece into the lead frame. Also, if the crystal piece is thin, it is easily damaged by falling or external impact. Furthermore, there is a problem in that the oscillation frequency fluctuates due to distortion occurring at the boundary between the electrode on the plate surface of the crystal blank and the crystal blank.

For this reason, it was necessary to strictly control the bending, parallelism, twisting, etc. of the lead/de terminals so as not to cause distortion to the crystal blank. Then, when the strain stress acts on the crystal piece and fc′ja,
There was a problem in that the electrical and mechanical properties of the crystal piece deteriorated.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and can increase the mechanical strength of the crystal blank, thereby reducing the strain stress acting on the crystal blank, and also preventing the deterioration of characteristics due to aging. The purpose is to provide a crystal oscillation device with good electrical and mechanical characteristics and less deterioration of the characteristics.

[Summary of the invention]

The present invention is characterized in that concave electrode pieces having electrode films on opposing surfaces are provided in close contact with both sides of a crystal piece that excites piezoelectric vibrations.

[Embodiments of the invention]

An embodiment of the present invention will be described in detail below with reference to the drawings. 11. FIG.

In the figure, xfi is a crystal piece that excites piezoelectric vibration. This crystal piece, for example, moves the two axes of the crystal in the Y-axis direction by approximately 35,815 mm.
AT cut out from a plane perpendicular to the 2' axis rotated by '
It is a cut crystal piece. Reference numeral 2 denotes a pair of electrode pieces provided in close contact with both side plate surfaces of the crystal piece 1. Each electrode piece 2
The surface facing the crystal blank l is formed into a concave surface 2, and an electrode film 2:l' is formed on this concave surface. It is preferable that the electrode piece 2 is made of quartz or a glass insulating material having a coefficient of thermal expansion approximately equal to that of the crystal piece 1. Therefore, the Z-plate cut out from the plane perpendicular to the two axes of the crystal has approximately the same coefficient of thermal expansion and exhibits no piezoelectric properties, making it suitable for use as the electrode piece 2. The concave surface 2 of the electrode piece 2 may be formed by etching, for example.

For example, in a crystal resonator whose fundamental wave is 30 MHz OAT cut, the thickness of the crystal piece 1 is about 50 μm. When electrode pieces 2 made of AT-cut quartz plates are similarly provided on both side plate surfaces, if the thickness is 0.1 m, the depth of the concave surfaces 2 may be about 20 μm. In this case, the total thickness of the vibrator is approximately 0.25 wx, and its mechanical strength can be greatly increased. And the electrode film 22
can be led out to the outside to excite vibrations.

In addition, since the electrode m22 faces the crystal blank 1 with a gap between the electrodes and the electrode does not come into close contact with the crystal blank 1, the vibration of the crystal blank 1 is not inhibited, and the shadow 11 of changes over time due to oxidation of the electrode etc.
Therefore, frequency fluctuations can be prevented.

Further, in order not to impede the vibration of the crystal piece l, the depth of the recess 21 is sufficient to be 20 μm, and this can be easily realized by a technique such as etching.

The frequency response of a crystal resonator having such a configuration is, for example, as shown in FIG. 2, consisting of a main resonant frequency f of the crystal piece 1 and a sub-resonant frequency f generated by the electrode piece 2.

However, by using a thick plate so as to obtain sufficient strength for the electrode piece 2, the sub-resonant frequency 120 can be lowered and the equivalent resistance can be increased, thereby causing no problem. By using crystal piece 1 and pole piece 2 having substantially the same coefficient of thermal expansion, the adverse effect on multi-temperature characteristics can also be eliminated.

The third example is a diagram showing an example of a crystal oscillator to which the present invention is applied, in which one electrode piece 2 is sprinkled on a paste 3 using an adhesive or the like.

Then, it is connected to the electrode film 22 of the electrode piece 2 via a pair of terminals 3xf leads 1M5z inserted through the paste 3. By covering the pace 3 with a cap (not shown), the external shape can be made similar to that of a conventional crystal resonator housed in a metal case.

FIG. 4 is a side view showing another embodiment of the present invention.

Paste 3 has an appropriate electrode film formed on the surface of alumina. In this way, even if the outer periphery is directly molded with a suitable resin or the like, there will be no cracks that will impair the vibration characteristics of the crystal piece l, and the entire piece can be molded into a techno part without the lead terminal tube.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to provide a crystal resonator which improves the mechanical strength of the crystal piece in particular, has good vibration resistance and impact resistance, and has stable electrical and mechanical characteristics with little change over time. can.

[Brief explanation of the drawing]

1st drawing A sectional view showing an embodiment of the present invention, 2nd prisoner company 1st
Figure 3 shows the frequency paving stones of the crystal oscillator shown in the figure.
FIG. 4 is a diagram showing different examples of the crystal resonator of the present invention. 1... Crystal piece, 2... Electrode piece, 2... Concave surface, 2
2...tffl membrane, s...pace.

Claims (6)

[Claims] (1) A crystal piece that is excited with piezoelectric vibration, and a pair of electrode pieces that are provided in close contact with both sides of this crystal piece and have a concave surface facing the crystal piece, and an electrode film is provided on this concave surface. A crystal oscillator equipped with. (2) A crystal resonator according to claim 1, characterized in that the coefficient of thermal expansion of the pair of electrode pieces is equal to that of the crystal piece. (3) A crystal resonator according to claim 1, wherein the pair of electrode pieces is made of glass. (4) A crystal resonator according to claim 1, wherein the pair of electrode pieces is made of a crystal plate. (5) A crystal resonator, wherein the crystal piece according to claim 1 is an AT plate. (6) A crystal resonator according to claim 5, wherein the pair of electrode pieces is a Z plate.