JPH0434569Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a piezoelectric oscillator used as a clock source of a microcomputer incorporated in an electronic device or the like.

(Prior art and its problems) The prior art will be explained using a hermetically sealed crystal oscillator as an example. A crystal oscillator is constructed by installing a crystal vibrating element and circuit elements such as IC chips, which make up an oscillation circuit, on a wiring board and integrally hermetically sealing them with a can. This crystal vibrating blank plate is electrically and mechanically connected with a conductive adhesive to a cylindrical metal support member that is electrically connected to the wiring on the board. However, when conducting a time-course test (for example, at 85℃ for several hundred hours),
Substrate (e.g. alumina substrate) and support member (metal)
Distortion occurs because the coefficient of thermal expansion differs between the two. This is because, since the support member is a solid cylinder, the stress due to its distortion is hardly alleviated and is transmitted to the crystal vibrating blank plate on the support member. On the other hand, the conductive adhesive gradually hardens during the aging test. For this reason, the crystal vibrating blank is firmly fixed in a stress-loaded state, and as a result, the electrical characteristics of the crystal vibrating blank as a circuit element are changed, significantly impairing reliability. In order to solve the above-mentioned drawbacks, the supporting member was constructed of a metal plate as shown in FIG. 6 in an attempt to eliminate the stress load on the crystal vibrating blank caused by thermal distortion. This crystal oscillator has lead terminals 11, 12, 1
3 and 14, an alumina insulating substrate 8 having an electrode pattern (not shown) printed on the base 1, and an IC placed at a predetermined position on the insulating substrate 8. It consists of a group of circuit elements 44 such as resistors and capacitors, a crystal vibrating element plate 3 which is a piezoelectric vibrating element, and a can (not shown) for hermetically sealing these circuit elements. The crystal vibrating plate 3 is supported in a floating state from the insulating substrate 8 via support members 91 and 92, which are formed by bending metal plates on the insulating substrate 8, so that the vibration at the time of resonance is not mechanically inhibited by others. ing. When a plate-shaped supporting member is used as in this conventional example, the distortion stress is alleviated to some extent due to its flexibility, and the electrical characteristics of the crystal vibrating element as a circuit element are also stabilized to some extent.

In this way, the crystal vibrating blank aims to function as a circuit element through mechanical vibration, and is extremely delicate, so how to support and install it is an important issue. In order not to inhibit vibration, it is preferable that the mechanical connection between the crystal vibrating blank and the support member be small, and the smaller the support member itself, the less the adverse effects of the above-mentioned thermal distortion will occur.
However, the smaller the entire supporting member is, the more
This has the disadvantage that the efficiency of installing the support member on the substrate, that is, the workability is reduced.

Furthermore, since conventional support members need to be installed on the substrate, connection failures may occur at the connection points between the two, and installation processes are also required from a manufacturing perspective, resulting in high costs for crystal oscillators. It was connected to.

(Purpose of the invention) The present invention was made to solve the above-mentioned drawbacks. It transmits almost no distortion due to heat or external shock to the piezoelectric vibrating element, which is extremely sensitive to external influences, and can be used as a circuit element. The purpose of the present invention is to provide a piezoelectric oscillator that has high reliability, can be miniaturized without considering the location of supporting members on the board, and can reduce costs by reducing manufacturing man-hours or improving workability. be.

(Structure of the invention) The piezoelectric oscillator according to the invention includes a lower layer made of a metal plate that is bendable and has good plastic workability, and an upper layer made of a substrate partially or entirely made of a thin insulator.
A piezoelectric vibrating element supporting part formed by bending a part of this substrate diagonally upward, a printed wiring pattern electrode formed in a predetermined pattern on the upper surface of the substrate including the piezoelectric vibrating element supporting part, and the piezoelectric vibrating element a piezoelectric vibrating element plate supported by a plate support part and having at least a pair of excitation electrodes electrically connected to a pattern electrode formed on the support part, and arranged at a predetermined position on the substrate; A circuit element that constitutes an oscillation circuit together with the piezoelectric vibrating element by being electrically connected by the pattern electrode, and a case that airtightly seals the substrate and the piezoelectric vibrating element on the substrate and the circuit element. It is characterized by:

(Function of the invention) According to the invention, a metal-based substrate that is bendable and easy to be plastically worked is used, a necessary pattern electrode is formed on this substrate, and circuit elements are arranged according to this pattern electrode. At the same time, since a part of the substrate is used as a support part for the piezoelectric vibrating element, there is no need to provide a new support member as in the past, which eliminates the problem of poor connection between the board and the support member as in the past. will not occur. In addition, by using a part of the board as the support part, for example, the support member that was conventionally required is self-supporting, and there is no need to consider the work of attaching the support member to the board, such as having a structure that does not easily fall down. The support portion may be thin and configured to provide sufficient spring action.

(Embodiments of the invention) First embodiment A first embodiment of the invention will be described with reference to the drawings, taking a crystal oscillator as an example. FIG. 1 is a perspective view showing the internal structure of a crystal oscillator, and FIG. 2 is a partially enlarged view showing the substrate structure. Note that the same structural parts as in the conventional example will be described using the same numbers.

This crystal oscillator roughly consists of a base 1 on which lead terminals are implanted, a substrate 2 installed on top of the base 1 and integrated with supporting parts 22 and 23, and a substrate 2.
A crystal vibration plate 3 installed at a predetermined position on the top;
It consists of circuit elements 41 and 42, and a metal can (not shown) that shields these boards from the outside and hermetically seals them. Next, each part will be explained in detail. The base 1 has a rectangular parallelepiped shape as a whole and is made of a metal shell, and electrically independent lead terminals 11 to 14 are arranged at the four corners of the base 1 through an insulating material such as glass. Further, a flange portion serving as an edge is provided at the lower part of the base, and serves as an airtight sealing portion with the flange portion of the can.

The substrate 2 has a multilayer structure as shown in FIG. That is, the lower layer 20 is made of a bendable material such as aluminum, copper, or iron and has high plastic workability, and the upper layer 21 is made of a flexible material such as polyimide that does not inhibit the bendability of the lower layer material. A thin insulating layer is formed. This insulating layer is provided on at least the entire upper surface of the lower layer 20 and in the through holes through which the four lead terminals 11 to 14 pass. A predetermined pattern electrode 5 is arranged on the top of this insulating layer by printed wiring technology, and is configured to be ultimately connected to a lead terminal (however, the details are not shown). Although not shown, the pattern electrode 5, the crystal vibrating element plate 3, and the circuit elements 41, 42
This pattern electrode 5 is covered with a so-called green resist for protecting the electrode, except for a terminal portion (not shown) which is a connection point with the electrode.

The support parts 22 and 23 are constructed by cutting a part of the substrate 2 and bending it obliquely upward. Although not shown, patterned electrodes are printed and wired on these support parts.

The crystal vibrating plate 3 is circular, and has an excitation electrode 31 and an extraction electrode 32 formed on the front and back surfaces (the back surface is not shown), and is installed between the supporting parts, and has a conductive bonding member 61, They are electrically and mechanically joined at 62. The circuit elements 41 and 42 are ICs, resistors,
This is a capacitor, etc., and in this example, the support part 2
It is installed under the crystal vibrating element plate 3 which is floated from the substrate 2 at points 2 and 23.

After the crystal vibrating element plate 3 and the circuit elements 41 and 42 are installed on the substrate as described above, they are hermetically sealed in the can in an inert gas atmosphere.

Second Embodiment A second embodiment of the present invention will be described with reference to the drawings. FIG. 3 is a perspective view showing the second embodiment, and FIG. 4 is a plan view showing the substrate used in the second embodiment and the electrode pattern on the substrate. Note that the same structural parts as in the first embodiment will be described using the same numbers.

The substrate 7 installed on the base has a two-layer structure (not shown) with the lower layer being an aluminum plate and the upper layer being a polyimide film, as in the first embodiment, and as shown in FIG. 4, circuit elements are mainly installed. It is divided into a region 7a and a crystal vibration blank plate installation region 7b having elongated support portions 72 and 73. A predetermined pattern electrode 5 is printed and wired on this substrate 7, and of course pattern electrodes 51, 5 are also provided on the support parts 72, 73.
2 is formed. The support portions 72 and 73 are bent diagonally upward in advance, and among these, the crystal vibrating blank plate installation portions 721 and 731 are processed so as to be substantially parallel to the substrate (unbent portion). The crystal vibrating blank plate 3 on which the excitation electrode 31 and the extraction electrode 32 are formed is installed in the installation parts 721 and 731, and is electrically and mechanically joined using conductive joining materials 61 and 62. Note that a 1-chip IC, which is the circuit element 43, is installed in the circuit element installation area.

With this structure, the support parts 72 and 73 extend diagonally upward from the circuit element installation part of the board, so the spring action is very large, and external shocks and thermal distortion shown in the conventional example are large. It is possible to attenuate various types of stress transmitted to the crystal vibrating blank plate 3 as much as possible.

Third Embodiment Third and fourth embodiments of the present invention will be described with reference to FIGS. 5a and 5b. FIG. 5a is a diagram showing a substrate structure according to a third embodiment, and FIG. 5b is a diagram showing a substrate structure according to a fourth embodiment. Since these figures only show the structure of the substrate, illustrations of the base, lead terminal through holes, pattern electrodes, piezoelectric vibrating element, circuit elements, etc. are omitted.

If the upper surface of the base is circular, a circular substrate is required, but in such a case, the circumference of the circular substrate 74 may be cut and bent diagonally upward to form supporting portions 75 and 76, as shown in FIG. 5a. . The circular crystal vibrating blank plate is electrically and mechanically connected to installation parts 751 and 761 at the tip of the support part. FIG. 5b shows a case in which the substrate is square in plan view, and similar to FIG. 5a, the support portions 78 and 79 may be formed by cutting around the periphery of the substrate and bending it diagonally upward. In addition, 7
81,791 is an installation part.

In these embodiments, since the periphery of the substrate is used as the support section, space efficiency is excellent, and the spring action of the support section is also large.

In the above embodiments, an airtight terminal using a metal base and a metal can is exemplified as a case, but the present invention is not limited to this. For example, a ceramic package or a resin package can be used as the case. may also be used. In addition, it is possible to omit only a portion of the upper layer of the insulator on the board, for example, connect several ground electrodes to this exposed metal plate, use the metal plate as a common line, and then connect this metal plate to the ground terminal provided on the case. may be connected to.
Note that an insulating film may be provided on the lower surface of the metal plate of the lower layer of the substrate as necessary depending on the structure of the lead electrodes, terminals, etc. of the case to be used.

(Effects of the invention) According to the invention, a bendable and easily plastically processable metal-based substrate is used, and a part of the substrate is used as a support for the piezoelectric vibrating element, so that circuit elements can be mounted on the substrate. In addition to mounting, the piezoelectric vibrating element can be mounted without intervening a support member. Therefore, there is no need to provide a new support member as in the past, and there is no problem of poor connection between the board and the support member, and the support part can be configured without considering the workability of attaching the support member to the board. The piezoelectric vibrating plate can be supported by a miniaturized support part that absorbs and alleviates various stresses that adversely affect the vibration of the piezoelectric vibrating plate, reducing manufacturing man-hours and creating a highly reliable piezoelectric oscillator. can be obtained.

[Brief explanation of drawings]

Figures 1 and 2 show the first embodiment, and Figure 3 shows the first embodiment.
Fig. 4 shows the second embodiment, Fig. 5a shows the third embodiment, Fig. 5b shows the fourth embodiment, and Fig. 6 shows the conventional example. FIG. 2, 7, 74, 77, 8...Substrate, 22, 2
3, 72, 73, 75, 76, 78, 79...Support part, 5...Pattern electrode.

Claims (1)

[Claims for Utility Model Registration] (1) The lower layer is made of a metal plate that is bendable and has good plastic workability, and the upper layer is partially or entirely made of a substrate made of a thin insulator, and a part of this substrate is placed diagonally upward. A piezoelectric vibrating element support part formed by bending the
A pattern electrode of printed wiring formed in a predetermined pattern on the upper surface of a substrate including a piezoelectric vibrating element support part, and a pattern electrode supported by the piezoelectric vibrating element support part and formed on this support part are electrically connected. a piezoelectric vibrating element having at least a pair of excitation electrodes connected to the substrate; and a piezoelectric vibrating element arranged at a predetermined position on the substrate and electrically connected by the pattern electrode to connect the piezoelectric vibrating element and an oscillation circuit. A piezoelectric oscillator comprising a circuit element that constitutes the circuit element, and a case that airtightly seals the circuit element and the piezoelectric vibrating element plate on the substrate and the base plate. (2) The piezoelectric oscillator according to claim 1, wherein the lower layer of the substrate is made of aluminum, iron, or copper, and the upper surface is an insulating layer of polyimide. (3) The board consists of a circuit element installation area and a piezoelectric vibrating element installation area from which a supporting part extends obliquely upward, and a piezoelectric vibrating element is installed in the piezoelectric vibrating element installation area near the tip of this supporting part. Install a vibrating plate,
and the excitation electrode formed on the piezoelectric vibrating element plate and the pattern electrode formed on the piezoelectric vibrating element installation part are electrically connected, as claimed in claims 1 and 2 of the utility model registration claims. Piezoelectric oscillator. (4) The substrate is cut in the vicinity of its periphery to form a supporting portion along the periphery, and a piezoelectric vibrating material plate is installed in the piezoelectric vibrating material mounting portion near the tip of this supporting portion, and the piezoelectric vibrating material is A piezoelectric oscillator according to claims 1 and 2 of the utility model registration, characterized in that an excitation electrode formed on a blank plate and a pattern electrode formed on a piezoelectric vibrating blank plate installation part are electrically connected.