JPS6119138B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a crystal resonator comprising two or more crystal oscillation pieces hermetically sealed in the same airtight container.

SUMMARY OF THE INVENTION An object of the present invention is to simplify the structure of a crystal resonator formed by hermetically sealing two or more crystal oscillation pieces in the same airtight container, downsize it, and provide it at low cost.

Depending on the cutting direction from the crystal axis, the crystal oscillator piece
There are many types such as AT cut, NT cut, and X cut, but each has its own frequency temperature characteristics, so there is a limit to the frequency stability in the practical temperature range. Therefore, in recent years, by using a combination of two or more crystal oscillation pieces with different performances, the frequency temperature characteristics of each are offset, resulting in frequency stability that could not be obtained with a single crystal oscillation piece. Attempts are being made to obtain. In this case, for small devices such as crystal watches,
Since two or more crystal oscillator pieces are housed in the same airtight container, the volume of the entire crystal resonator increases, causing mounting problems. Therefore, it is necessary to reduce the volume of the entire crystal resonator and make it more compact.

FIG. 1 shows a conventional crystal resonator in which two crystal oscillation pieces are hermetically sealed in the same airtight container. The two crystal oscillation pieces 1 and 2 are mounted on a lower case 3 and an upper case 4 made of ceramic with brazing material 5 such as solder. The upper and lower cases are hermetically sealed with brazing material 6 having a lower melting point than the brazing material 5. 7, 8,
Reference numerals 9 and 10 indicate external electrode lead wires that have been attached to the upper and lower cases in advance.

The drawbacks of the conventional example described above are listed below.

1. The structure of the crystal resonator is improved by mounting the two crystal oscillator pieces separately on the upper and lower cases, and once the crystal oscillator pieces are mounted, the upper and lower cases must be airtightly sealed. is complicated, and the volume of the crystal resonator becomes large because the mounting part and the hermetic sealing part must be provided separately.

2. The need to use brazing materials with different melting points for the mount portion and the hermetic sealing portion requires extremely strict control of conditions such as the composition of the brazing material and working temperature, which increases manufacturing costs.

3. Since the upper and lower cases are made of ceramic, it is not possible to adjust the frequency of the crystal oscillation piece by irradiating a laser beam from the outside after the case is hermetically sealed.

The present invention overcomes all of the above-mentioned drawbacks.

A crystal resonator according to the present invention is shown in FIGS. 2 and 3. FIG. 2 is an exploded view showing the structure of the crystal resonator shown in FIG. 3. Reference numerals 11 and 12 refer to tuning forks 11a and 12a having different performances, and frames 11b and 12 in which the bases of the tuning forks extend to surround the tuning forks.
It is a crystal oscillation piece having a tuning fork 11a, 12
An electrode film of chromium, gold, etc. is formed on a.
(Not shown) A metal film made of a metal material such as gold, silver, or solder is formed on the frames 11b and 12b to ensure airtight sealing. (Not shown.)13
and 14 are upper and lower cases each having recesses 13a and 14a in the center, and the hermetic sealing portion is made of eutectic material with the metal material formed in the frame portions 11b and 12b of the crystal oscillation piece, or a thermocompression bonding method. When air-tight sealing is performed using another air-tight sealing method, metal materials 13b, 14 such as gold, silver, and platinum that are suitable for thermocompression bonding.
b are formed respectively.

The material of the case is a material with a coefficient of thermal expansion similar to that of the crystal oscillator pieces 11 and 12, in order to prevent the occurrence of thermal distortion due to heating during hermetically sealing. In order to adjust the frequency of the crystal oscillation piece by irradiating the crystal oscillation piece with a laser beam from the outside, it is preferable to use a transparent material, such as quartz or glass having a similar coefficient of thermal expansion. Other materials include metal materials and ceramics. 13c, 14c, 14d
is an external electrode extraction part. Reference numeral 14d denotes a common electrode of the crystal oscillation pieces 11 and 12, which passes through a part 12c (the electrode is not shown) of the side surface of the frame 12b of the crystal oscillation piece 12, and then connects to the part 14 of the side surface of the case 14.
It connects to e and is pulled out to 14d. The electrodes of the crystal oscillator piece are drawn out to 13c and 14c through side surfaces 13d and 14f of the upper and lower cases, respectively.

After stacking the parts created as described above, the eutectic material is melted by heating in a vacuum, or the metal materials are bonded together by thermocompression by heating and pressurizing. After sealing, a crystal resonator made by stacking two crystal oscillation pieces in the thickness direction as shown in FIG. 3 is completed. Note that the gap between the two crystal oscillation pieces is provided by the thickness of the eutectic material or other metal material used for hermetic sealing.

The advantages of the crystal resonator according to the present invention are listed below.

1. The mounting part and hermetic sealing part of the upper and lower cases of the two crystal oscillator pieces are the same, and the mounting and hermetic sealing operations can be performed simultaneously in one process. Therefore, the structure of the crystal resonator is simple and can greatly contribute to miniaturization.

As described in 2.1, since the structure and manufacturing process of the crystal resonator are simple, the bonding operation can be completed in one time, the bonding reliability is high, and it is possible to provide the crystal resonator at low cost.

3. Because the upper and lower cases are made of transparent material, it is possible to adjust the frequency of the two crystal oscillation pieces by irradiating a laser beam from the outside after the case is hermetically sealed. For this reason, it is possible to manufacture with an even higher yield.

Application examples of the crystal resonator according to the present invention are shown in FIG.
It is shown in FIGS. 5 and 6. FIG. 4 shows an application example in which a partition plate 17 is provided between two crystal oscillation pieces 15 and 16 to prevent mutual interference of the oscillation frequencies of the crystal oscillation pieces. 18 and 19 are the upper and lower cases. 17a is a recess provided in the center of the partition plate 17. In the hermetic sealing part, a eutectic material or other metal material 17b is formed in the same manner as in the case of the case shown in FIG. 2 described above, and each of the front and back hermetic sealing parts , conduction is achieved through a metal film 17c formed on the side surface. The material of the partition plate, the hermetic sealing, and other methods are the same as those shown in FIG. 2 described above.

An advantage of the present invention is that mutual interference between the oscillation frequencies of the two crystal oscillation pieces can be prevented.

[Brief explanation of the drawing]

Figure 1 shows a conventional example of a crystal resonator. FIG. 2 is an exploded view of a crystal resonator according to the present invention. FIG. 3 shows an embodiment of a crystal resonator according to the present invention. Figure 4 is an example of an application of the present invention to a crystal resonator. 1 and 2 are crystal oscillation pieces, 3 is a lower case, 4 is an upper case, and 5 and 6 are brazing materials. 7, 8, 9, 1
0 is an external electrode lead wire. 11 and 12 are crystal oscillation pieces, 11a and 12a are tuning forks, 11
b and 12b are frame portions. 13 and 14 are upper and lower cases, and 13a and 14a are recesses. or,
13b, 14b are metal materials, 13c, 14c, 1
3d and 14d, external electrode extraction parts 14e and 14f are side parts. 15 and 16 are crystal oscillation pieces;
17 is a partition plate, and 19 is an upper and lower case. 17
17b is a metal material, and 17c is a metal film. 20a to 20n are crystal oscillation pieces, and 21a to 21n are partition plates.

Claims (1)

[Claims] 1. In a crystal resonator formed by two crystal oscillation pieces hermetically sealed in the same airtight container, each of the crystal oscillation pieces has a circumferential frame integrally formed,
The two crystal oscillation pieces are stacked in the thickness direction and hermetically sealed by stacking the two frames via an airtight member and fixing the airtight container on each frame. A crystal oscillator featuring