JPS6119556Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a contour vibrator.

More specifically, the present invention relates to a holding structure for a contour vibrator.

The purpose of the present invention is to put into practical use a highly stable and inexpensive crystal resonator.

As quartz crystal watches become more precise, thickness-slip quartz crystal units, especially AT-cut quartz crystal units, are attracting attention. By using this AT-cut crystal oscillator, the time accuracy is considerably improved, but this AT-cut crystal oscillator also has the following drawbacks. In other words, the resonant frequency is MHz, which cannot be made smaller.
They are very expensive in terms of bandwidth, consume a lot of power, and cannot be manufactured in large quantities with the same performance. Due to these drawbacks, AT-cut crystal resonators have not been put into practical use despite their high frequency stability. The crystal resonator of the present invention overcomes the above drawbacks and aims to put the GT cut crystal resonator into practical use as an inexpensive crystal resonator for high-precision electronic watches.

This will be explained below with reference to the drawings.

FIG. 1 shows a specific example of a conventional contour vibrating crystal resonator (GT cut resonator). In the figure, 11
12 is a contour vibrating crystal oscillator body, 12 is an electrode attached by vapor deposition on the surface of 11, and 13 is a holder that supports the oscillator and takes out the electrode. The vibration mode of this vibrator is contour vibration, and the temperature-resonance frequency characteristic has an excellent characteristic of flattening around room temperature. Furthermore, the resonant frequency is lower than that of an AT-cut crystal resonator, and the current consumption is also lower. However, in the conventional example, the resonance frequency is about 100 KHz, the size is 40 cm square, and the thickness is about 3 mm. However, in order to maintain excellent electrical characteristics, many considerations must be made in the process of forming a vibrator body from raw crystal. In other words, in order to obtain good resonant frequency aging characteristics and a high Q value, it is impossible to use a forming process that leaves distortion in the vibrator body, such as a processing method using a diamond cutter. A processing method that does not cause distortion, such as finishing, must be adopted. Therefore, in the example of Figure 1,
Since the vibrator body has six surfaces, it must be polished six times, or even if the opposing planes are polished at the same time, it must be polished three times. extremely difficult. or,
In this GT cut crystal resonator, the ratio of the vertical and horizontal sides affects the frequency temperature characteristics, and each length affects the resonance frequency, so the shape accuracy is extremely strict and processing is extremely difficult. Ta. Moreover, the properties of products made by such processing vary widely, making it difficult to mass-produce products with excellent properties.

FIG. 2 is a diagram of a specific example of the present invention.

A is a sketch, and b is a sectional view. In the figure,
21 is a vibrating part of a contour vibrating crystal resonator, 22 is an electrode part molded integrally with the vibrating part, and 23 is a support part. 24 is a holder, 25 is a lead wire, and 26 is a metal ball. In this case, the front and back electrodes, crystal resonator section, and support section are formed by etching. By applying a voltage between the metal films attached to their back surfaces by vapor deposition or the like, contour sliding vibration can be generated. An example of the process for obtaining the crystal resonator shown in FIG. 2 will be explained in detail below.

FIG. 3 is a diagram showing the direction in which the crystal thin plate according to the present invention is cut out from the crystal raw stone. In the figure, X, Y, and Z are the electrical axis, mechanical axis, and optical axis of the crystal, respectively. 30 is a crystal plate for making a conventional GT cut crystal resonator, and 31 is a crystal plate for obtaining a crystal resonator of the present invention. = 45° ~ 55°) It is cut from the crystal rough in a rotated position. After this quartz plate is cut out, it is thoroughly polished to remove processing distortion during the cutting process, and is finished into a thin quartz plate with a predetermined thickness. A crystal resonator is formed from this crystal thin plate by photoetching, as will be explained below.

First, metal films of, for example, chromium and gold are deposited on both the front and back surfaces of a thin crystal plate by vapor deposition. Next, as shown in FIG. 4, the chrome-gold metal film is left on the shape 41 of the crystal resonator by photoetching. After that, this crystal thin plate,
For example, if the crystal is immersed in a mixed solution of ammonium fluoride, the portion of the crystal not covered by the chrome-gold metal film will be dissolved, resulting in a large number of crystal oscillators connected in series. Thereafter, by applying a weak force to the connecting portion 42 of FIG. 4, a separated crystal resonator can be obtained. In this example, the vibrator-shaped chrome-gold metal film serves as a protective mask when melting the crystal, and at the same time, after completion, it directly serves as the electrode film of the vibrator. However, it goes without saying that if the number of steps is increased, the electrodes and the vibrator can have different shapes.

Also, it goes without saying that the completed vibrator is made tilted by an angle β (=45°) with respect to the X-axis. As described above, the crystal resonator of the present invention has the following features.

(1) There is a large degree of freedom in machining the shape, and ultra-compact vibrators can be formed.

(2) The rotation axis (β in Figure 3) can be freely selected within the plane of the crystal thin plate, making it possible to adjust the temperature characteristics.

(3) Since the external dimensions can be finished with high precision, contour slip crystal resonators can be manufactured with uniform temperature characteristics and resonant frequencies.

(4) Since the electrode part and support part are also formed at the same time as the external forming, the number of man-hours is reduced.

(5) Since the support part is molded integrally with the vibrating part, there is less vibration loss due to the support, and at the same time, variations in the characteristics of the vibrator due to the support are reduced.

(6) Since the support part is formed integrally with the vibrating part, the space of the support part is small, and support wires are not required, so it is possible to make it ultra-compact.

Next, a vibrator holding structure according to the present invention will be explained.

A crystal plate manufactured by the method described above,
As shown in FIG. 2, the support portion 23 and the electrode film 22 on the surface of the crystal plate are bonded together via metal balls. Specifically, the electrode 22 is a two-layer film with strong adhesion, consisting of a chromium base and gold vapor-deposited thereon.
3 is made of a springy metal such as phosphor bronze, beryllium copper, or nickel, and its surface is plated with gold.

With a ball bonder used for IC wiring, a gold ball 26 is thermocompressed onto a gold electrode film 22, and a support wire 2 is plated with gold over the gold ball 26.
3 is crimped by thermocompression bonding. The concrete example shown in FIG. 2 is made in this way.

Another specific example of the present invention is shown in FIG. a
is a sketch, and b is a cross-sectional view. As already mentioned,
A gold ball 56 is attached to the gold electrode film 52 using a ball bonder.
The metal ball and the holder 54 are bonded together using solder. In order to establish electrical continuity on the top surface, the electrode on the top surface and the plug 55 are also connected to the holder 5.
4 and the plug are lead bonded. If a plug electrically connected to the holder 54 is provided, the latter lead bonding described above is not necessary.

The crystal resonator having the support structure according to the present invention as described above has the following advantages not found in the prior art.

That is: 1. It is possible to reduce the cost because it does not require an expensive nail-shaped head detent wire with a collapsed tip as in the conventional case.

2. Since no solder is used to bond the crystal plate and the supporting member, there is no instability in characteristics due to variations in solder, and there is little change in characteristics over time.

3. The bonding area between the crystal plate and the support member is determined by the ball sandwiched therein, so the shape accuracy of the support member is not required.

4. Since the crystal plate and the supporting member are bonded by thermocompression bonding via a metal ball, the bonding area can be reduced, the Q of the vibrator is increased, and it is less susceptible to the effects of adhesion and the supporting member.

5. Since the crystal plate and the supporting member are bonded by thermocompression bonding through the balls, the bonding area can be made small, the resonant frequency of the crystal plate is not affected by the adhesion or the supporting member, and there is little change in the resonant frequency over time. .

6. Because the crystal plate and the supporting member are bonded by thermocompression bonding through the balls, the bonding strength is extremely strong.

7. Since no solder is used, assembly work can be automated and the number of man-hours can be reduced.

8. Simple structure and can be miniaturized.

Although the crystal resonator has been described above as a specific example of the present invention, it goes without saying that the advantages of the present invention are the same for other piezoelectric resonators.

As described above, the crystal resonator having the crystal plate and holding structure according to the present invention is small, has a very simple structure, and can be manufactured by a process suitable for mass production, so it is very inexpensive. . This will greatly contribute to the commercialization of inexpensive, ultra-compact, and ultra-high precision crystal resonators.

[Brief explanation of the drawing]

Figure 1 shows a conventional contour vibrating crystal oscillator. FIG. 2 is a diagram of a specific example of the contour vibrating crystal resonator of the present invention.
FIG. 3 is a diagram showing the cutting angle of the crystal thin plate according to the present invention. FIG. 4 is a diagram showing a method of manufacturing a crystal resonator according to the present invention. FIG. 5 is a diagram of another specific example of the present invention. 11, 21, 41, 51... Contour vibrating crystal resonator, 12, 22, 52... Electrode film, 13, 23...
...Support part, 24, 54...Holder, 25, 55
...Plug, 26, 56...Metal ball, 30...Crystal plate for making a conventional contour slip crystal resonator.

Claims (1)

[Claims for Utility Model Registration] In a support structure for a GT cut oscillator formed by photoetching, a gold electrode disposed on each of two opposing planes of the GT cut oscillator, approximately at the center of each of the two planes. A gold ball is thermocompression bonded onto the surface of at least one gold electrode at a node in the section, and a supporting member is placed opposite to the plane of the GT cut resonator and is adhesively fixed to the gold ball. Support structure of GT cut oscillator.