JPS6118372B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a crystal resonator, and more particularly to a crystal resonator that can suppress spurious vibrations and improve vibration characteristics.

A crystal resonator made of a piezoelectric crystal such as quartz, lithium tantalate, or lithium niobate causes distortion and oscillates at a certain frequency when a predetermined electric field is applied through an excitation electrode. The oscillation frequency changes depending on the size, thickness, etc. of the excitation electrode.

In a conventional crystal resonator, as shown in FIG. 1, an excitation electrode 2 and an extraction electrode 3 are first formed on the surface of a resonator body 1 by vapor deposition, sputtering, or the like. The excitation electrode 2 is formed to have sufficient strength and thickness so that it does not easily separate from the surface of the vibrator body 1, but the thickness has been determined experimentally so that the oscillation frequency of the vibrator body 1 reaches a target value. is determined to be slightly higher than Thereafter, a predetermined voltage is applied to the excitation electrode 2 via the extraction electrode 3, and while observing the oscillation frequency of the vibrator body 1, a peg 4 for frequency adjustment is formed on a part of the surface of the excitation electrode 2. The oscillation frequency was being adjusted. In the crystal resonator configured in this manner, the frequency adjustment knobs 4 are locally thickly formed on the surface of the excitation electrode 2, so that the distribution of strain occurring in the vibrator body 1 is It has a defect that changes due to the formation, tends to induce spurious vibrations, makes it impossible to obtain good vibration characteristics, and tends to deteriorate temperature characteristics. For this reason, when mass-producing the above crystal resonators, the variation in characteristics is large and the yield is poor, and it is difficult to match masks for high-precision products, and it takes a long time to make adjustments to make the characteristics uniform. Therefore, it has been difficult to reduce manufacturing costs.

The present invention eliminates the above-mentioned conventional defects, suppresses spurious vibrations, improves vibration characteristics, and facilitates shortening frequency adjustment time, thereby reducing manufacturing costs. We propose a crystal oscillator that can

The invention will now be described in detail with reference to the illustrated embodiments.

A second example showing an embodiment of the crystal oscillator according to the present invention.
In the figure, numeral 5 is the AT-cut crystal resonator body. On one surface of the vibrator body 5, for example, the bottom surface, there is an excitation electrode 6 formed to have a predetermined size D' and thickness t', and an extraction electrode extending from the excitation electrode 6 to one end of the vibrator body 5. 7 is formed.

The other surface of the vibrator body 5, for example, the upper surface as the surface opposite to the lower surface, is provided with an auxiliary electrode 8 having a minimum size D ₁ and thickness t ₁ necessary for exciting the vibrator body 5. and an extraction electrode 9 extending from the auxiliary electrode 8 to one end of the vibrator body 5
is formed. The above-mentioned excitation electrode 6, auxiliary electrode 8, and extraction electrodes 7 and 9 are made of a thin metal film formed by means such as vapor deposition or sputtering.

On the surface of the auxiliary electrode 8 and the surface of the vibrator main body 5, the size of the auxiliary electrode 8 is larger than that of the auxiliary electrode 8.
The thick excitation electrode 10 is formed by means such as vapor deposition or sputtering. When forming the excitation electrode 10 described above, a voltage is applied to the excitation electrode 6 and the auxiliary electrode 8 via the extraction electrodes 7 and 9. to oscillate the vibrator main body 5, and while measuring the oscillation frequency, spurious characteristics, Q value, etc., the excitation electrode 10
The oscillation frequency is adjusted by changing the size or formation position of the thin film metal constituting the metal, and the Q value and vibration characteristics are adjusted to be high.

By configuring the crystal resonator in this way, the oscillation frequency can be adjusted while suppressing spurious by changing the size, thickness, etc. of the excitation electrode 10 while measuring the oscillation frequency via the auxiliary electrode 8 formed thin and small. In addition to being able to adjust accurately, there is no need to form relatively thick grooves on the surface of the excitation electrode as in conventional crystal vibrators, and the auxiliary electrode 8 and excitation electrode 10 formed on the vibrator body 5 can be The included electrodes can be formed to have substantially the same thickness and the required minimum thickness, and the strain occurring in the vibrator body 5 can be made uniform. Therefore,
Spurious vibrations can be suppressed, the Q value and vibration characteristics can be improved, and temperature characteristics can also be improved. Therefore, even when mass-producing the crystal resonators mentioned above, it is easy to make the characteristics uniform and improve the yield.Moreover, even in the case of high-precision products, mask alignment is easy and the frequency adjustment time is This makes it possible to reduce the manufacturing cost, and it is also possible to fine-tune the oscillation frequency while checking the compatibility with electronic circuits such as oscillation circuits.

Although the details of the present invention have been described above with reference to illustrated embodiments, the present invention is not limited to what is illustrated. For example, auxiliary electrodes and excitation electrodes may be formed on both sides of the vibrator body. You can also do it. In this case, it is desirable to perform simultaneous vapor deposition on both sides.

As described above, the crystal resonator according to the present invention includes an auxiliary electrode having the minimum size and thickness necessary to excite the resonator main body, and the resonator main body is excited through the auxiliary electrode. By forming an excitation electrode larger and thicker than the above-mentioned auxiliary electrode while measuring the oscillation frequency, etc., the oscillation frequency can be adjusted accurately, and it is easy to shorten the adjustment time and reduce manufacturing costs. Since the thickness of the auxiliary electrode formed under the excitation electrode can be made extremely thin, the strain that occurs in the vibrator body when applying voltage through the excitation electrode to excite the vibrator body can be reduced. In addition, it is possible to suppress spurious vibrations, increase the Q value, improve vibration characteristics, and improve temperature characteristics. It is possible to sufficiently achieve the intended purpose, such as reducing variations in vibration characteristics and making it easier to achieve uniform quality, and has great practical effects.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing a conventional crystal oscillator, and FIG. 2 is a side sectional view showing an embodiment of the crystal oscillator according to the present invention. 1, 5...Resonator main body of the crystal resonator, 6...Excitation electrode, 7,9...Extraction electrode, 8...Auxiliary material formed to the minimum size and thickness necessary to excite the resonator main body. Electrode, 10...Excitation electrode formed to cover the auxiliary electrode, _D1 ...Size of the auxiliary electrode, _t1 ...Thickness of the auxiliary electrode, D, D'...Size of the excitation electrode, t , t′... Thickness of excitation electrode.

Claims (1)

[Claims] 1. A vibrator body, a first excitation electrode formed on one side of this vibrator body, and a minimum size and thickness formed on the other side of this vibrator body to excite this vibrator body. at least one auxiliary electrode having a size and thickness, and a second excitation electrode formed overlappingly on the upper surface of the auxiliary electrode and having a shape sufficiently larger than the auxiliary electrode, the size and thickness of the second excitation electrode A crystal oscillator characterized in that it is configured to obtain a predetermined vibration frequency.