JP2006129304A - Piezoelectric vibrator and piezoelectric oscillator - Google Patents

Abstract

In a conventional piezoelectric vibrator and piezoelectric oscillator, when a piezoelectric vibration element having a different external dimension is used, a package in which an electrode pad for element connection corresponding to the external dimension is used is designed and used. Each time a different piezoelectric vibration element is used, it is necessary to redesign the package in which the element connection electrode pad is formed in accordance with the mounting of the piezoelectric vibration element, resulting in a decrease in productivity and cost.
In the piezoelectric vibrator and the piezoelectric oscillator according to the present invention, each element connecting electrode pad has one short side disposed in the vicinity of one short side of the bottom surface of the recess space, and the element connecting electrode pad. The longitudinal dimension of the electrode pad is 30% or more of the longitudinal dimension of the concave space, and each element connecting electrode pad is symmetrical with respect to the center line on the short side of the container body. It is formed in the position.
[Selection] Figure 1

Description

  The present invention relates to a piezoelectric vibrator and a piezoelectric oscillator in which a piezoelectric vibration element is mounted.

  Conventionally, various electronic parts have been used in electronic devices such as portable communication devices. Among them, piezoelectric vibrators and piezoelectric oscillators that serve as reference signal generation sources, etc., are airtightly sealed inside the container. It is used as a stopped electronic component.

  The structure of such a conventional piezoelectric vibrator will be described. FIG. 4 shows a surface mount type piezoelectric vibrator. That is, a rectangular flat plate insulating layer 31a and a frame-shaped insulating layer 31b are stacked, and a metal is formed on a frame-shaped main surface opposite to the stacked surface of the frame-shaped insulating layer 31b (hereinafter referred to as a container side wall top). The layer 35 is formed to constitute the container body 31. The main surface of the flat insulating layer 31a exposed in the container internal space 32 surrounded by the frame insulating layer 31b and the flat insulating layer 31a is drawn out from the excitation electrode film 38 formed in the piezoelectric vibration element 34. A rectangular element connecting electrode pad 33 is formed in accordance with the shape and dimension of the container connecting electrode film, and a pair of electrodes electrically connected to the element connecting electrode pad 33 via a conductive adhesive. The piezoelectric vibration element 34 having the container connecting electrode is fixedly conducted.

  The entire main surface on the container side covers the metal layer 35 formed on the top of the container side wall of the container body 31 in which the piezoelectric vibration element 34 is mounted in the container internal space 32 so as to cover the opening of the container internal space 32. A package having a package structure in which a container inner space 32 is hermetically sealed by disposing a metal lid 36 clad with a metal brazing material and joining the lid 36 and the metal layer 35 by seam welding or the like. It has been known. (For example, see Patent Document 1.)

  In such a piezoelectric vibrator 30, a fluctuation voltage from the outside is applied to the excitation electrode film 38 formed on the piezoelectric vibration element 34 via the external connection electrode pad 37 provided on the lower surface of the container body 31. Then, thickness shear vibration is caused at a predetermined frequency according to the characteristics of the piezoelectric vibration element 34, and a reference signal having a predetermined frequency is oscillated and output by an external oscillation circuit based on the resonance frequency. Such a reference signal is used as a clock signal in an electronic device such as a portable communication device.

  As a conventional piezoelectric oscillator, a piezoelectric vibration element and an integrated circuit element incorporating an oscillation circuit are mounted inside a container body, and the opening of the container body is hermetically sealed with a metal lid. It has been known. At this time, the piezoelectric vibration element is formed with a rectangular element connection electrode pad that matches the shape and dimension of the container connection electrode film drawn from the excitation electrode film formed on the main surface of the piezoelectric vibration element. A piezoelectric oscillator is configured by being electrically connected to the element connecting electrode pad via a conductive adhesive and also electrically connected to the integrated circuit element.

  For such piezoelectric vibrators and piezoelectric oscillators, the following prior art documents are known.

JP 2001-274649 A Japanese Patent Application Laid-Open No. 07-297666

  The applicant has not found any prior art documents related to the present invention other than the prior art documents specified by the prior art document information described above by the time of filing of the present application.

  However, in the conventional piezoelectric vibrator and piezoelectric oscillator, when using piezoelectric vibration elements having different outer dimensions, the package having the electrode pads for element connection that match the outer dimensions is designed and used. Each time a different piezoelectric vibration element is used, it is necessary to redesign the container body in which the element connection electrode pad is formed in accordance with the mounting of the piezoelectric vibration element, resulting in a decrease in productivity and cost.

  The present invention has been devised in view of the above drawbacks, and an object thereof is to provide a piezoelectric vibrator that is easy to handle and excellent in productivity.

In order to solve the above problems, the piezoelectric vibrator of the present invention has a pair of element connection electrode pads formed in a recessed space opened in one main surface formed in a rectangular container body, The piezoelectric vibration element is disposed and fixed on the element connection electrode pad, and the excitation electrode film formed on the front and back main surfaces of the piezoelectric vibration element and the element connection electrode pad are electrically connected. In the piezoelectric vibrator,
Each element connection electrode pad has one short side disposed in the vicinity of one short side of the bottom surface of the recessed space, and the longitudinal dimension of the element connecting electrode pad is the longitudinal dimension of the recessed space. Further, each element connection electrode pad is formed at a position which is line-symmetric with respect to the center line on the short side of the container body.

  Further, in the piezoelectric vibrator, the shape of the element connection electrode pad is such that the two long sides of each element connection electrode pad form a desired taper angle toward the short side center line of the container body. The piezoelectric vibrator according to claim 1, wherein the piezoelectric vibrator has a trapezoidal shape in which a side formed in the vicinity of one short side of the bottom surface of the concave space is a long side.

Further, a second recess space is formed in the first recess space opened on one main surface formed in the rectangular container body via a step portion, and a pair of element connection is formed on the step portion. An electrode pad is formed, and an integrated circuit element including an oscillation circuit is mounted in the second recess space. The piezoelectric vibration element is disposed and fixed on the element connection electrode pad. In the piezoelectric oscillator configured by electrically connecting the excitation electrode film formed on the front and back main surfaces, the element connection electrode pad, and the integrated circuit element,
One short side of each element connection electrode pad is disposed in the vicinity where the stepped portion and one short side inner surface of the container body intersect, and the length in the longitudinal direction of the element connection electrode pad is the first dimension. It is formed with a dimension of 30% or more of the longitudinal dimension of one recess space, and each element connecting electrode pad is formed at a position that is line symmetric with respect to the center line on the short side of the container body. It is characterized by that.

  Furthermore, also in the piezoelectric oscillator, the shape of the element connection electrode pad is such that the two sides on the container body long side of each element connection electrode pad have a desired taper angle toward the center line on the short side of the container body. It is characterized by a trapezoidal shape in which the side formed in the vicinity of one short side of the bottom surface of the concave space is a long side.

  According to the piezoelectric vibrator and the piezoelectric oscillator of the present invention, the length in the longitudinal direction of the element connection electrode pad for mounting the piezoelectric vibration element is 30% or more of the dimension in the long side direction of the bottom surface of the recess space. Because it can be placed at a position that matches the length of each piezoelectric vibration element, there is no need to change the package design each time the external dimensions of the piezoelectric vibration element change. The productivity of the oscillator can be improved, and the design and manufacturing costs can be kept low.

  According to another embodiment of the piezoelectric vibrator and the piezoelectric oscillator of the present invention, the shape of the element connecting electrode pad for mounting the piezoelectric vibration element is formed in a trapezoidal shape, so that any shape of the piezoelectric vibration element (particularly, Even when a piezoelectric vibration element having a small external dimension is used, the main surface corner portion of the piezoelectric vibration element can be held, so that the connection strength is maintained and the vibration characteristics of the piezoelectric vibration element are not adversely affected. It becomes possible.

  Therefore, by using the piezoelectric vibrator and the piezoelectric oscillator according to the present invention, it is possible to provide a piezoelectric vibrator and a piezoelectric oscillator with high reliability, high production efficiency, and low cost.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.
1 is an exploded perspective view of a surface mount type piezoelectric vibrator according to an embodiment of the present invention, and FIG. 2A is a plan view of a container body constituting the piezoelectric vibrator shown in FIG. (B) is a top view of the container body of other embodiment. The piezoelectric vibrator shown in these drawings has a structure which is a rectangular container body 1 in which a piezoelectric vibration element 5 is accommodated. FIG. 3 is a perspective view of a container body (mounted with an integrated circuit element) constituting a surface-mounted piezoelectric oscillator according to an embodiment of the present invention. In each drawing, parts or structures that are not necessarily required for this description are not shown. In addition, some parts or structures are exaggerated for the sake of clarity in the description of the drawings.

  In the piezoelectric vibrator shown in FIGS. 1, 2A and 2B, the container body 1 includes an insulating substrate 2 made of a ceramic material such as glass-ceramic and alumina ceramic, and 42 The seal ring 3 is made of a metal such as alloy, Kovar, phosphor bronze, and the like, and the lid 4 is made of the same metal as the seal ring 3. The seal ring 3 is attached to the upper surface of the substrate 2, and the upper surface thereof is attached. The container body 1 is configured by placing and fixing the lid body 4.

  The container body 1 has quartz, lithium tantalate, lithium niobate, or the like in the interior thereof, specifically, in a space surrounded by the upper surface of the substrate 2, the inner surface of the seal ring 3, and the lower surface of the lid 4. The piezoelectric vibration element 5 formed of the piezoelectric material is accommodated and hermetically sealed. The substrate 2 has an excitation electrode film 6 formed on the front and back main surfaces of the piezoelectric vibration element 5. A pair of element connection electrode pads 7 to be electrically connected is formed. These pads are connected to each other necessary for electrical connection through a wiring conductor formed on the surface of the substrate 2 or a via-hole conductor embedded in the substrate 2.

  When the substrate 2 of the container body 1 is made of a ceramic material such as glass-ceramic, for example, on the surface of a ceramic green sheet obtained by adding and mixing an appropriate organic solvent to the ceramic material powder. A conductor paste to be a wiring conductor is applied by well-known screen printing or the like, and a plurality of these are laminated, press-molded, and then fired at a high temperature.

  The seal ring 3 and the lid body 4 of the container body 1 are manufactured by forming a metal such as 42 alloy into a predetermined shape by using a conventionally known metal processing method, and the obtained seal ring 3 is attached to the substrate 2. After brazing on a conductor layer previously deposited on the upper surface, and subsequently mounting and fixing the piezoelectric vibration element 5 to the element connection electrode pad 7 formed on the upper surface of the substrate 2 using a conductive adhesive. The piezoelectric vibrator is assembled by joining the above-described lid body 4 to the upper surface of the seal ring 3 by a conventionally known seam welding or the like. In this way, when the seal ring 3 and the lid body 4 are joined by seam welding, a Ni plating layer, an Au plating layer, or the like is previously deposited on the surfaces of the seal ring 3 and the lid body 4.

  On the other hand, the piezoelectric vibration element 5 accommodated in the container body 1 is formed of a pair of excitation electrode films 6 on both main surfaces of a crystal piece cut along a predetermined crystal axis when, for example, crystal is used. When formed, and when a fluctuation voltage from the outside is applied to the crystal piece via the pair of excitation electrode films 6, excitation vibration occurs at a predetermined frequency.

  The piezoelectric vibration element 5 is mounted on the substrate 2 by electrically connecting a pair of excitation electrode films 6 to an element connection electrode pad 7 formed on the upper surface of the substrate 2 through a conductive adhesive. Thus, electrical connection and mechanical connection between the piezoelectric vibration element 5 and the container body 1 are simultaneously made.

  The element connection electrode pad 7 is exposed to the upper surface of the substrate 2 and the recessed space formed by the seal ring 3 (which is the same as the bottom surface of the recessed space, hereinafter referred to as the bottom surface of the recessed space). One short side 7a is disposed in the vicinity of one short side, and the dimensions of the long sides 7c and 7d of the element connection electrode pad 7 are 30% or more of the longitudinal dimension of the recess space. Further, each element connection electrode pad 7 is formed at a position which is symmetrical with respect to the center line A on the short side of the substrate 2. As a result, the piezoelectric vibration elements 5 having different outer shape dimensions can be arranged and fixed in the recess space, so that it is not necessary to change the container body 1 for each piezoelectric vibration element to be used, and the productivity of the piezoelectric vibrator is improved. It becomes possible to make it. (Fig. 2 (b))

  Further, as shown in FIG. 2A, the shape of each element connection electrode pad 7 is such that the side 7c on the long side of each element connection electrode pad is directed toward the center line A on the short side of the substrate 2. The trapezoidal shape is formed with a desired taper angle, and the side 7a of the element connection electrode pad 7 formed in the vicinity of one short side of the bottom surface of the recess space is longer than the side 7b of the opposing element connection electrode pad 7. By forming the piezoelectric vibration element 5 in any outer shape, the corner portion of the main surface of the piezoelectric vibration element 5 can be held, so that the connection strength is maintained and the vibration characteristics of the piezoelectric vibration element 5 are maintained. It is possible not to adversely affect

  Here, if the lid body 4 of the container body 1 is connected to the GND terminal of the external connection terminals 9 arranged on the lower surface of the container body 1 via the wiring conductor of the container body 1, Since the shield function is imparted by grounding the lid 4, the piezoelectric vibration element 5 can be better protected than an unnecessary electrical action from the outside. Therefore, the lid 4 of the container body 1 is preferably connected to the external terminal 9 for the ground terminal via the wiring conductor of the container body 1.

  Further, four external terminals 9 are provided on the lower surface of the container body 1, and these external terminals 10 are used when a surface-mounted crystal oscillator is mounted on an external electric circuit such as a mother board (not shown). It is electrically connected to the circuit wiring of the external electric circuit by soldering or the like.

  In the embodiment described above, the lid 4 of the container body 1 is bonded to the substrate 2 via the seal ring 3. Instead, a metallized pattern for bonding is formed on the upper surface of the substrate 2. In addition, the lid 4 may be directly welded to the metallized pattern. In the embodiment described above, the seal ring 3 is directly attached to the upper surface of the substrate of the container body 1. Instead of this, a frame made of a ceramic material or the like made of the same material as the substrate 2 is provided on the upper surface of the substrate 2. After the body is attached integrally, the seal ring 3 may be attached to the upper surface of the frame. Furthermore, a gold-tin brazing material may be used instead of the seal ring 3.

  In the present embodiment, a piezoelectric vibrator in which the piezoelectric vibration element 5 is mounted in the recessed space formed in the container body 1 is disclosed. However, the gist of the present invention is not limited to the piezoelectric vibrator. As shown in FIG. 3, another space is formed in the recessed space of the container body on which the piezoelectric vibration element is mounted, or a space different from the recessed space is formed in the container body, and the oscillation circuit is formed in the other space. Built-in integrated circuit element 8 and an electronic element constituting an oscillation circuit are mounted, and a piezoelectric vibration element, an integrated circuit element or an electronic element and an external connection terminal are electrically connected by a conductor wiring or a via hole. Also in the piezoelectric oscillator, the same operation effect as the operation effect produced in the present invention can be achieved. Furthermore, the present invention is not limited to the above-described embodiment, and various modifications and improvements can be made without departing from the scope of the present invention. For example, a piezoelectric vibration element plate is provided on the upper surface of a flat insulating substrate. The effect of the present invention is also the same in a piezoelectric vibrator which is mounted and covered with a so-called hat (hat with hat) so that the piezoelectric vibration element is hermetically sealed. Play.

FIG. 1 is an exploded perspective view showing a piezoelectric vibrator according to the present invention. 2A is a plan view of a container body constituting the piezoelectric vibrator shown in FIG. 1, and FIG. 2B is a plan view of another form of container body constituting the piezoelectric vibrator of the present invention. FIG. FIG. 3 is a perspective view illustrating an embodiment of a container body constituting the piezoelectric oscillator according to the present invention. FIG. 4 is an exploded perspective view showing a conventional piezoelectric vibrator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Container body 4 ... Cover body 5 ... Piezoelectric vibration element 6 ... Electrode film for excitation 7 ... Electrode pad for element connection 8 ... Integrated circuit element

Claims (3)

A pair of element connection electrode pads are formed in a recessed space opened in one main surface of the rectangular container body, and a piezoelectric vibration element is disposed and fixed on the element connection electrode pads. In addition, in the piezoelectric vibrator that is electrically connected between the excitation electrode film formed on the front and back main surfaces of the piezoelectric vibration element and the element connection electrode pad,
Each of the element connection electrode pads has one short side disposed in the vicinity of one short side of the bottom surface of the recess space, and the longitudinal dimension of the element connection electrode pad is the length of the recess space. The electrode pad for element connection is formed at a position that is line-symmetric with respect to the center line on the short side of the container body. Piezoelectric vibrator. A second recess space is formed in the first recess space opened in one main surface of the rectangular container body via a stepped portion, and a pair of element connecting electrode pads is formed in the stepped portion. Is formed, and an integrated circuit element having an oscillation circuit is mounted in the second recess space, and a piezoelectric vibration element is disposed and fixed on the element connection electrode pad, and the piezoelectric vibration element In the piezoelectric oscillator configured to be electrically connected between the excitation electrode film formed on the front and back main surfaces of the electrode, the element connection electrode pad, and the integrated circuit element,
Each of the element connection electrode pads has one short side disposed in the vicinity of the stepped portion and one short side inner surface of the container body, and the longitudinal direction of the element connection electrode pad Are formed so as to be 30% or more of the longitudinal dimension of the first recess space, and each element connection electrode pad is symmetrical with respect to the center line on the short side of the container body. A piezoelectric oscillator characterized by being formed at a position.   The element connection electrode pad has a trapezoidal shape in which two sides on the long side of the container body of each element connection electrode pad form a desired taper angle toward the center line. The piezoelectric vibrator or the piezoelectric oscillator according to claim 1 or 2.

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