JP2007013719A - Crystal oscillator - Google Patents

Abstract

【Task】
An object of the present invention is to provide a support structure for a crystal base plate that reduces the stress applied to the excitation region of the crystal base plate while strengthening the bondability of the bonding material to the crystal base plate.
[Solution]
In order to achieve the above object, the present invention provides a quartz resonator in which a metal electrode is disposed on a round quartz crystal plate, an excitation region is formed, and an extraction electrode extending from the metal electrode is supported and fixed. A circumferential through groove is formed inside the outer periphery of the plate, a notch is provided in a part of the through groove as an extraction electrode region, and the extraction electrode extends to the extraction electrode region extending from the excitation region. The object is achieved by being kept conductive in the extraction electrode region.
[Selection] Figure 1

Description

  As an example, the present invention provides a crystal base plate that reduces stress strain applied to the excitation region of the crystal base plate when the crystal base plate is held by a support plate and a bonding material connected to two metal terminals extending from the base of the hermetic structure. It is related with the support structure.

  With the rapid growth of the mobile communication market in recent years, the demand for communication equipment has increased dramatically. At present, crystal oscillators that are used as a clock source for generating a reference frequency in communication equipment are used in the surroundings. There is also a demand for ensuring that a frequency signal serving as a desired reference is stably output even under a severer environment.

  As a typical example of a structure for holding a crystal base plate, a crystal resonator having a round plate shape shown in FIG. 3 is shown. The above-described quartz crystal holding structure is formed by forming excitation electrodes on the front and back sides of the quartz base plate, and connecting with a support plate connected to the extraction electrode routed from the excitation electrode and the two metal terminals extending from the metal base with a bonding material And hold it. The holding part has a so-called clip-type structure, and holds the crystal element plate in a fashionable manner, holds the crystal element plate directly between a pair of flat support plates, or a metal terminal In addition, there are various forms such as a shape in which a slit is formed at a place where the crystal base plate is held on the support plate to hold the crystal base plate.

  In addition, as a method of connecting the extraction electrode routed from the excitation electrode, there are a case where a metal having a relatively low melting point such as solder is used and a case where a conductive adhesive is used.

  The above-described round plate-shaped quartz base plate is in a rare presence in the shape of a mainstream quartz base plate having a strip shape in recent years. This is because the round plate-shaped quartz base plate is a quartz base plate specially manufactured to obtain a highly stable frequency output. The rectangular shape of the recent quartz base plate has a rectangular outer shape with a long side dimension of 2 to 6 mm and a short side of 2 mm or less, whereas the round plate shape has a diameter of around 10 mm compared to the rectangular shape. Have large external dimensions. As for the thickness of the quartz base plate, high-order overtone oscillation is often used, and the round-plate-shaped quartz base plate is much thicker than the strip-shaped quartz base plate.

  As a typical example of the purpose of use of the crystal resonator shown in FIG. 3, the frequency output characteristics are obtained by using a thermostat inside a crystal oscillator called an oven controlled crystal oscillator (OCXO). There is a form of an oscillator that can maintain a stable state.

  A crystal resonator having a high stability characteristic that is mounted and used in a thermostat crystal oscillator called OCXO is roughly one point between 70 ° C. and 90 ° C. (temperature deviation ± 0.3). In order to obtain stable frequency characteristics (aging characteristics), it is used in a temperature environment maintained at a temperature of (° C) and the output frequency fluctuation due to secular change is suppressed. The material used is AuGe (gold-germanium alloy) or a highly heat-resistant polyimide conductive paste that generates less internal gas, is stable against changes in thermal expansion, and has little effect on the quartz base plate. Often done.

Japanese Patent Laid-Open No. 7-240656 Japanese Patent Laid-Open No. 11-214949 In addition, the applicant has not found any prior art documents related to the present invention by the time of the filing of the application other than the prior art documents specified by the prior art document information described above. It was.

An object of the present invention is to use a bonding material such as AuGe or polyimide to improve the bondability with a crystal element plate and reduce the generation of stress applied from the support plate to the excitation region of the crystal element plate. It is to provide a support structure.
In short, one of the factors that influence the aging characteristics shown in the prior art is the stress on the quartz base plate from the support part, also called the support plate. For example, the stress due to the difference in thermal expansion coefficient of each material and the shrinkage at the time of joining the quartz base plates, or the weld pressure deforms the metal base of the crystal unit during the welding in the sealing process, and the stress accompanying the deformation Is transmitted to the crystal base plate through the metal terminal and the support plate, so that asymmetrical twist and torsional force is applied to the crystal base plate and the holding portion from the support (holding) portion to the crystal base plate, There is a great influence on the characteristics of the crystal unit. In some cases, the high-stable frequency output characteristic inherent to the crystal base plate is hindered, and the aging characteristic of the crystal unit may be significantly deteriorated.

One of the reasons mentioned above is that when holding the quartz base plate using AuGe brazing material, the brazing material is temporarily melted and fixed by cooling after holding the quartz base plate on the support. The internal stress remains on the quartz base plate due to the variation in temperature distribution when the material hardens, that is, the difference in thermal expansion coefficient.
On the other hand, when sealing the quartz base plate with a can, the stress on the metal base at the time of sealing is also transmitted to the crystal base plate via the support plate. Internal stress remains.

  Therefore, it is possible to reduce the stress and strain components applied from the support part to the crystal base plate by the structure of the holding part that electrically and mechanically joins the support part and the crystal base plate. However, the present situation is that no effective means can be found, although a supporting method and a bonding material for the holding portion for the purpose have been proposed.

  Therefore, in order to solve the above-described problem, the present invention provides a crystal resonator in which a metal electrode is arranged on a round plate-shaped quartz base plate to form an excitation region, and an extraction electrode extending from the metal electrode is supported and fixed. A circular through groove (slit or continuous through hole) is formed inside the outer periphery of the quartz base plate, and a notch is provided in a part of the through groove as an extraction electrode region, and the extraction electrode is the excitation region A crystal resonator extending to an extraction electrode region extending from the electrode and held conductive in the extraction electrode region. Further, the part of the uncut portion described above is a crystal resonator characterized by being present in a positional relationship of 180 degrees or 90 degrees of the quartz base plate.

  In short, a quartz crystal substrate is supported by a support plate fixed to two metal terminals extending from a metal base, and the quartz base plate is routed from the excitation electrodes on the front and back of the quartz substrate to the tip of the support structure. A portion of the quartz base plate, which is the extracted electrode region, is joined using a bonding material (eg, AuGe, solder, or conductive adhesive) to establish an electrical connection. The problem is solved by realizing a holding structure that is firmly fixed and held in the extraction electrode region constituted by the through groove and is not affected by the stress of the holding portion with respect to the excitation region of the quartz base plate.

  In addition to being able to be held firmly according to the present invention, the stress relaxation at the time of holding can be relaxed in the excitation region of the quartz base plate from the extraction electrode region, which cannot be achieved by the conventional structure. It can be realized, reducing the stress to the crystal base plate that is received from the support part, maintaining the stable frequency characteristics of the crystal base plate itself, and good and stable even in the form of a crystal resonator mounted on a hermetic base Frequency output can be obtained. As a result, the yield of the manufacturing process can be improved and the manufacturing cost can be reduced. Moreover, by reducing the stress change phenomenon due to secular change by relaxing the internal stress on the quartz base plate, a stable output frequency can be obtained over a long period of time.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In addition, the same code | symbol in each figure shall show the same object. FIG. 1 is a partial cross-sectional view showing the concept of the support structure of the crystal resonator 5 of the present invention. Excitation electrodes 7 are formed on the front and back of the quartz base plate 1, and an extraction electrode 8 routed from the excitation electrode 7 is fixed to a support plate 4 connected to two metal terminals 3 extending from the metal base 2 with a bonding material. By doing so, the quartz base plate 1 is held and the electrical conduction is obtained. In the figure, a lid and a cap for configuring the sealed container are not shown.

  Accordingly, as an example, the quartz base plate 1 is fixed to the tip portion of the metal terminal 3 made of a material that penetrates the metal base 2 while the metal base 2 is hermetically sealed by a hermetic container made of glass. In general, a support plate 4 or the like may be arranged at the tip portion of the metal terminal 3 so that the crystal base plate 1 can be reliably mounted.

  In short, in the crystal resonator in which the metal electrode is arranged on the circular plate-shaped quartz base plate 1 to form the excitation region, and the extraction electrode extending from the metal electrode is supported and fixed, the circular plate-shaped extraction electrode A circular through groove 6 is formed inside the outer periphery of the crystal base plate, a notch 9 is provided in a part of the through groove 6, and the crystal base plate is sandwiched between the outer peripheral portion of the crystal base plate and the through groove 6. Thus, the lead electrode region extending from the excitation region is kept conductive.

  FIG. 1 shows an example in which a part of the notch (position) 9 described above as an example of the present invention is such that an extraction electrode region is formed at a position facing the crystal base plate at 180 degrees, and FIG. Thus, in the case of a crystal resonator having a structure in which the crystal base plate 1 is supported at four points, an extraction electrode region is formed in a positional relationship divided by 90 degrees. In addition, the dimension of the through-groove 6 described above is sufficient if the excitation electrode region and the extraction electrode region can be divided, and the size is not questioned. Further, the formation of the through groove 6 described above is realized by an etching process or a mechanical method such as sand blasting.

  FIG. 2 is a conceptual diagram in which extraction electrode regions 8 are formed with a 90-degree division positional relationship according to another embodiment of the present invention. FIG. 1 is drawn with the concept of supporting the quartz base plate vertically, while FIG. 2 is drawn with the concept of supporting horizontally. Accordingly, FIG. 2A is a plan view of the quartz base plate, and FIG. 2B is a side view. The holding position of the quartz base plate is held by the bonding material with a positional relationship of 180 degrees with respect to the divided positional relationship of 90 degrees.

  In the embodiment of the present invention, only the case of two-point support (180 degrees) and four-point support (90 degrees) is described as an example. However, if there are some extraction electrode regions 8, the effect of the present invention can be obtained. Since it plays, the actual number of supporting points may be other than shown here. However, in that case, it is desirable to form the extraction electrode region 8 by equal division. The through grooves 6 and the notches 9 are formed by a sandblasting mechanical method or a chemical method such as an etching process.

It is a fragmentary sectional view which shows the concept of the support structure of the crystal oscillator of this invention. It is a fragmentary sectional view which shows the concept of the other Example of the support structure of the crystal oscillator of this invention. It is a fragmentary sectional view of a crystal oscillator with a form which holds a crystal blank using a support plate as a conventional example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Crystal base plate 2 ... Metal base 3 ... Metal terminal 4 ... Support plate 5 ... Crystal oscillator 6 ... Through groove 7 ... Excitation Electrode (region)
8. Extraction electrode (region)
9 ... Notch

Claims (1)

In a quartz crystal unit that arranges a metal electrode on a round plate-shaped quartz base plate to form an excitation region, and supports and fixes an extraction electrode extending from the metal electrode,
A circumferential through groove is formed on the inner periphery of the quartz base plate, and a notch is provided in a part of the through groove as an extraction electrode region, and the extraction electrode extends to the extraction electrode region extending from the excitation region. A crystal resonator, wherein the crystal resonator is conductive and held in the extraction electrode region.

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