JP2001102900A - Surface mount type piezoelectric oscillator - Google Patents

Abstract

(57) [Summary] [PROBLEMS] While maintaining a high P / V value of a tertiary overtone, it is possible to reduce only the P / V value of the fundamental wave vibration and to increase the reliability of external solder joints. Provided is a surface-mount type piezoelectric vibrator which can be increased in frequency, has a small fluctuation in oscillation frequency, and has high reliability in a use resistant environment in humid conditions. Kind Code: A1 Two lead terminals provided on a bottom surface of an insulating support plate, a piezoelectric vibrator disposed on the insulating support plate, and a piezoelectric vibrator disposed on the piezoelectric vibrator. And a conductive member 17 in a connection hole 15 formed in the thickness direction of the insulating support plate 2.
The protrusion 21 of the lead terminal 4 is connected to the lead electrodes 11 c and 12 a, and the insulating support plate is provided on both main surfaces of the piezoelectric substrate 7 corresponding to the outer periphery of the vibration electrodes 11 and 12 via the insulating adhesive 5. 2 and the protection plate 3 were bonded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface mount type piezoelectric oscillator.

[0002]

2. Description of the Related Art Conventionally, microcomputers and the like have been frequently used for communication equipment and electronic equipment, and a clock oscillation circuit and the like have been connected to such microcomputers. In such an oscillation circuit, two load capacitance components C ₁ and C ₂ are connected between both ends of the piezoelectric vibrator 1 and a ground potential, as in the equivalent circuit shown in FIG.
, A feedback resistor 5 and an inverter 6 were connected respectively.

In order to generate a clock signal by this oscillation circuit, the amplification factor in the amplifier circuit including the inverter 6 and the feedback resistor 5 is α, the phase shift amount is θ _1, and
When the feedback ratio in the feedback circuit composed of the piezoelectric vibrator 1 and the load capacitance components C ₁ and C ₂ is β and the phase shift amount is θ ₂ , the loop gain is α × β ≧ 1, and the phase shift amount is θ ₁ + θ
₂ = 360 ° × n (where n = 1, 2,...).

Generally, an amplifier comprising a feedback resistor 5 and an inverter 6 is built in a microcomputer. In order to obtain stable oscillation without causing non-oscillation or oscillation stop, the loop gain must be increased. To increase the loop gain, it is necessary to increase the P / V value of the piezoelectric vibrator that determines the gain of the feedback ratio β.

For example, in the case of a piezoelectric vibrator using a tertiary overtone of thickness longitudinal vibration, the P / V value of the tertiary overtone is increased while obtaining a stable oscillation at the tertiary overtone. The P / V value of the wave must be reduced. For this purpose, a vibration space is provided near the vibration electrode and the vibration electrode of the piezoelectric vibrator, the P / V value of the tertiary overtone is increased, and the upper and lower surfaces of the non-vibration part are sandwiched between the protection plates to thereby obtain the fundamental wave P. / V value was reduced.

Conventionally, ceramic oscillators using a piezoelectric vibrator include a type without a built-in load capacitance having an external load capacitance component and a type with a built-in load capacitor having two capacitor components. Yes, depending on the purpose and method of use.

In recent years, as devices are becoming smaller and thinner, for example, when they are incorporated into smaller and thinner devices such as IC cards and CD-ROMs, the thin type with no built-in load capacitance is replaced with a small and thin chip capacitor. Used in combination. Furthermore, utilizing the effect that the oscillation frequency changes depending on the value of the load capacitance, the variation in the oscillation frequency is combined with the optimum load capacitance to reduce the initial tolerance of the oscillation frequency.

[0008] In addition, mounting forms are roughly classified into two types, a lead pin type and a surface mounting type. At present, from a high-density automatic mounting technology to a printed wiring board, reflow soldering is performed together with other electronic components on the printed wiring board. The surface-mount type that can perform is mainly used.

In the surface-mount type ceramic oscillator, a vibration space is formed so as not to hinder the vibration operation of the piezoelectric oscillator, and the P / V value of the piezoelectric oscillator is kept large while forming an airtight structure. It is important how the size and height are reduced.

The P / V value is 20 log (Ra / Rb)
Where Ra is the anti-resonance impedance, Rb
Is defined as the resonance impedance.

In a conventional surface mount type piezoelectric vibrator, protective plates are arranged on the upper and lower surfaces of the piezoelectric vibrator, the piezoelectric vibrator and the protective plate are joined via an adhesive layer, and the side walls are electrically connected to the internal electrodes. There is known a piezoelectric vibrator having a three-layer structure in which electrodes serving as external terminals are removed (see, for example, JP-A-5-65118).

[0012]

However, in the conventional surface mount type piezoelectric oscillator as described above, when mounted on a printed wiring board, the solder becomes harder with cooling of the solder after reflow, so that the surface is hardened. There is a problem that a tensile stress is generated on the external terminals formed by sputtering or vapor deposition of the mounting type piezoelectric oscillator, so that the external electrodes are peeled off and the oscillation is stopped by disconnection between the external electrodes and the internal electrodes. Was.

Further, there is a problem that the oscillation frequency is greatly changed by the stress acting on the piezoelectric vibrator due to the solder joining.

Furthermore, when a heat cycle in which the temperature rise and fall is repeatedly applied is performed, the mechanical and thermal stresses associated with the solder joining between the printed wiring board and the external electrodes are reduced.
By repeatedly applying to the surface mount type piezoelectric vibrator, a large stress is concentrated on the adhesive layer for fixing the piezoelectric vibrator and the protection plate disposed on the upper and lower surfaces of the piezoelectric vibrator. There was a risk that the protection plate would peel off from the child. Therefore, when the device is operated in high humidity, there is a problem that the moisture does not penetrate and adhere to the vibrating electrode, the P / V value is greatly reduced, the oscillation is stopped, and the reliability in the use resistant environment cannot be obtained. .

The present invention has been devised in view of the above-mentioned problems, and has as its object the P / P of the third-order overtone.
While maintaining the V value at a high value, only the P / V value of the fundamental wave vibration can be reduced, and the size and height can be reduced.
Furthermore, the reliability of the solder joint with the outside can be dramatically improved, the fluctuation of the oscillation frequency is small even after mounting on the printed wiring board, and the protection plate is not peeled off from the piezoelectric vibrator even in the heat cycle. It is another object of the present invention to provide a surface mount type piezoelectric oscillator having improved reliability in a use environment in humid conditions.

[0016]

According to the present invention, there is provided a surface mount type piezoelectric oscillator provided on a bottom surface of an insulating support plate, and having a projecting portion projecting toward the inside of the insulating support plate.
One lead terminal and a pair of vibrating electrodes disposed on the insulating support plate and formed opposite to each other at the center of both main surfaces of the piezoelectric substrate, respectively, and connected to the pair of vibrating electrodes, respectively. A connecting electrode formed in the thickness direction of the insulating support plate, comprising: a piezoelectric vibrator in which the extraction electrode extends from the bottom surface of the piezoelectric substrate; and a protection plate disposed on the piezoelectric vibrator. The projecting portion of the lead terminal is connected to the lead electrode by a conductive member in the hole, and the insulating support is provided on both main surfaces of the piezoelectric substrate around the vibrating electrode via an insulating adhesive. A plate and the protective plate are bonded to each other.

By adopting such a configuration, a three-layer structure in which an insulating support plate integrally formed with two lead terminals and a protective plate are bonded to both surfaces of the piezoelectric vibrator via an insulating adhesive. And the height can be reduced.

Furthermore, it is desirable that both ends of the lead terminal are bent along the side surface of the insulating support plate. Two metal lead terminals serving as external terminals are integrally formed on the insulating support plate, and both ends of the lead terminal are bent along the side surface of the insulating support plate, thereby forming a connection between the printed wiring board and the lead terminal. In soldering, the solder melted by reflow solidifies and contracts due to cooling at the bent part of the lead terminal, and tensile stress is generated at both ends of the lead terminal, but both ends of the bent lead terminal have insulating properties. Since it is not fixed to the side surface of the support plate, both ends of the lead terminal are deformed by the generation of tensile stress, and the stress is relieved. As a result, the reliability of the solder joint between the piezoelectric vibrator and the printed wiring board can be significantly improved, and the solder vibrator hardly exerts any stress on the piezoelectric vibrator, and the rate of change of the oscillation frequency is greatly increased. Can be reduced.

Furthermore, even when a surface mount type piezoelectric oscillator fixed to a printed wiring board with solder is subjected to a heat cycle in which the temperature is repeatedly increased and decreased, the stress is relieved by the deformation of the lead terminals. In addition, the stress applied to the entire surface mount type piezoelectric vibrator is greatly reduced, and the peeling at the bonding portion between the weakest strength piezoelectric vibrator, the protection plate, and the insulating support plate can be eliminated. As a result, the sealing performance can be improved, and the device can be used stably even in a humid environment.

In addition, since the protruding portion of the lead terminal is electrically connected to the lead-out electrode by the conductive member filled in the connection hole formed in the thickness direction of the insulating support plate, it is easy and stable. Connection can be achieved, and the stop of oscillation due to disconnection between the vibrating electrode and the lead terminal can be eliminated.

Further, when the distance between the end of the piezoelectric substrate and the vibrating electrode is x, the conductive member is located at x / 3 to the distance from the end of the piezoelectric substrate.
It is desirable to be connected to the extraction electrode in the range of 2 × / 3. By adopting such a configuration, in particular, in a surface mount type piezoelectric oscillator using a third overtone, the P / V value of the third harmonic overtone of the thickness longitudinal vibration is maintained at a high value while the P / V value of the fundamental vibration is maintained. / V value can be reduced.

[0022]

1 is an external perspective view of a surface mount type piezoelectric oscillator according to the present invention, FIG. 2 is a sectional view taken along line AA of FIG. 1, and FIG. FIG. 4 is a sectional view taken along the line B, and FIG. 4 is an exploded perspective view.

In FIG. 1, reference numeral 1 denotes a piezoelectric vibrator, 2 denotes an insulating support plate, 3 denotes a protection plate, 4a and 4b denote lead terminals,
5 is an insulating adhesive. In FIG. 1, the insulating adhesive is shown by hatching for convenience.

As shown in FIGS. 1 to 3, the surface mount type piezoelectric oscillator according to the present invention includes an insulating adhesive 5 on an insulating support plate 2 on which two lead terminals 4a and 4b are integrally formed. The piezoelectric vibrator 1 is adhered, and a protective plate 3 is further adhered on the piezoelectric vibrator 1 via an insulating adhesive 5.

As shown in FIG. 4, a pair of vibrating electrodes 11 and 12 are formed opposite to each other at the center of both main surfaces of the piezoelectric substrate 7.

The piezoelectric substrate 7 is made of PT (lead titanate), PZ
Piezoelectric ceramic materials such as T (lead zirconate titanate),
It is formed from a single crystal material such as quartz, lithium tantalate, lithium niobate, and lithium tetrabutyrate.

A vibrating electrode 11 formed at the center of the upper surface of the upper surface of the piezoelectric substrate 7 is extended to the right end by an extraction electrode 11a, and further extended to a lower extraction electrode 11c via an extraction electrode 11b on the side surface. It has been extended. A vibrating electrode 12 formed at the center of the piezoelectric substrate 7
Are extended to the left end by the extraction electrode 12a.
Note that the extraction electrode 12a does not necessarily need to extend to the left end.

The vibrating electrodes 11 and 12 and the extraction electrode 11
a to c and 12a are formed of, for example, a thin film conductive film mainly composed of an Ag-based material, and the extraction electrodes 11b on the side surfaces of the piezoelectric substrate 7 are printed with a conductive paste mainly composed of an Ag-based material, for example. And a conductor film made of an Ag-based thin film formed by thermosetting, sputtering, or the like.

The insulating support plate 2 may be made of any material as long as it has an insulating property. For example, the insulating support plate 2 may be made of a ceramic material such as an alumina substrate or a resin material having excellent heat resistance such as polyimide or liquid crystal polymer. It is desirable to configure. Particularly, a composite material of a heat resistant resin and a ceramic whisker is preferable.

The insulating support plate 2 has a vibration electrode 12
A concave portion 13 is formed in a portion opposed to the above, to prevent contact between the vibration electrode 12 and the insulating support plate 2.

Further, the insulating support plate 2 has
One of the connection holes 15a and 15b is formed, and the inside thereof is filled with a conductive resin paste obtained by mixing a conductive metal powder such as Ag with an epoxy-based adhesive, and is cured with conductive members 17a and 17b. Is formed.

The protection plate 3 is made of ceramics such as an alumina substrate or a heat-resistant resin such as polyimide or liquid crystal polymer. A concave portion 19 is formed in a portion facing the vibration electrode 11, and the vibration electrode 11 and the protection plate 3 To prevent contact.

That is, the vibration supporting electrode 12 is provided on the insulating support plate 2.
A concave portion 13 is formed in a portion opposed to
A concave portion 19 is formed in a portion facing the vibration electrode 11, and a vibration space is formed around the vibration electrodes 11 and 12.
The insulating support plate 2 and the protection plate 3 are respectively bonded to the outer periphery of the vibration space, that is, both main surfaces of the piezoelectric substrate 7 around the vibration electrodes 11 and 12 via the insulating adhesive 5. I have.

In the above example, the concave portion 1 is formed in the insulating support plate 2.
3. The example in which the vibration space is formed by forming the concave portion 19 in the protection plate 3 has been described, but the vibration space may be formed by the thickness of the insulating adhesive 5.

On the bottom surface of the insulating support plate 2, lead terminals 4a and 4b made of nickel-white or phosphor bronze metal are integrally formed. As shown in FIG. 5, the lead terminals 4a and 4b are respectively provided with a protrusion 21 and an anchor 22.
These projections 21 are formed in the thickness direction of the insulating support plate 2 and constitute a part or all of the inner wall surfaces of the funnel-shaped connection holes 15a, 15b extending on the lower surface. . Lead terminals 4a, 4b and funnel-shaped connection hole 1
5a and 15b are formed by insert molding of a resin when the insulating support plate 2 is formed.

Also, both ends 25 of the lead terminals 4a, 4b
Are bent along the side surface of the insulating support plate 2, and both ends 25 are not bonded to the side surface of the insulating support plate 2.

The insulating support plate 2 and the protection plate 3 are bonded to both main surfaces of the piezoelectric substrate 7 corresponding to the outer periphery of the vibrating electrodes 11 and 12 via an insulating adhesive 5 respectively. The conductive members 17a and 17b are connected to the extraction electrodes 11c and 12a on the lower surface side of the piezoelectric vibrator 1.

When the distance between the end of the piezoelectric substrate 7 and the vibrating electrode 12 is x, the conductive members 17a and 17b are connected to the extraction electrodes 11c and 1c in the range of x / 3 to 2x / 3 from the end of the piezoelectric substrate 7.
2a.

In the surface mount type piezoelectric oscillator configured as described above, the insulating support plate 2 and the protective plate 3 are attached to the piezoelectric substrate 7 around the vibrating electrodes 11 and 12 by the insulating adhesive 5. And the vibrating electrodes 11 and 12 of the piezoelectric vibrator 1
And by forming a vibration space in the vicinity thereof, while maintaining the P / V value of the third harmonic at a high value, the fundamental wave P / V
The value can be suppressed to a small value, and a reduction in size and height can be achieved.

In particular, the end of the piezoelectric substrate 7 and the vibrating electrodes 11 and 12
When the distance from the piezoelectric substrate 7 is x, the conductive members 17a and 17b are connected to the extraction electrode 11 in the range of x / 3 to 2x / 3 from the end of the piezoelectric substrate 7.
By connecting to c and 12a, the P / V value of the fundamental wave can be greatly suppressed, and stable transmission can be obtained.

FIG. 6 shows the largest P / V of the fundamental wave vibration or the vibration in which the fundamental wave vibration and the spurious vibration are superimposed on the vibration energy trapping type oscillator of the third harmonic vibration operated at the oscillation frequency of 33.86 MHz. FIG. 5 is a view showing an FEM analysis of a vibration distribution that forms a piezoelectric substrate, as viewed from above a piezoelectric substrate.

According to this figure, x / 3 from the end of the piezoelectric substrate 7
It can be understood that there is a portion where the displacement due to the fundamental wave is strong in the range of ~ 2x / 3, and therefore, the conductive members 17 are attached to the extraction electrodes 11c and 12a of the portion where the displacement due to the fundamental wave is strong.
By joining a and 17b, fundamental wave vibration can be suppressed.

Further, in the surface mount type piezoelectric oscillator of the present invention, as shown in FIG. 3, when mounted on the printed wiring board 31, the solder 33 melted by reflow bending the lead terminals 4a, 4b. The solidification and shrinkage due to cooling at the portions cause tensile stress to occur at both ends 25 of the lead terminals 4a and 4b. However, since both ends 25 of the bent lead terminals 4a and 4b are not bonded to the side surfaces of the piezoelectric substrate 7, And both ends 25 of the lead terminals 4a, 4b against the occurrence of tensile stress.
Deform and relieve stress. Therefore, the reliability of the solder joint between the piezoelectric vibrator 1 and the printed wiring board 31 can be greatly improved, and the solder joint can
Almost no stress acts on the piezoelectric vibrator 1, and the rate of change of the oscillation frequency can be greatly reduced.

Further, even when a surface mount type piezoelectric oscillator fixed to a printed wiring board with solder is subjected to a heat cycle in which the temperature is repeatedly increased and decreased, the stress is relaxed by the deformation of the lead terminals 4a and 4b. As a result, the stress applied to the entire surface mount type piezoelectric oscillator is greatly reduced, and peeling of the insulating adhesive 5 having the weakest strength can be eliminated. It can be used stably in use.

The conductive member 17 filled in the connection holes 15a and 15b formed in the thickness direction of the insulating support plate 2 is provided.
The protrusions 21 of the lead terminals 4a, 4b
And the extraction electrodes 11c and 12a are electrically connected to each other.
It is possible to easily and stably make electrical connection, and it is possible to eliminate the stop of oscillation due to disconnection between the vibrating electrodes 11 and 12 and the lead terminals 4a and 4b.

The material of the insulating support plate 2 is, for example,
It is commonly used as a composite material of a heat-resistant resin such as polyester or polyetheretherketone used as a resin for liquid crystal polymers and a ceramic whisker such as potassium titanate, lead titanate or barium titanate. Injection moldability is better than composite materials with glass whiskers, and high dimensional stability is obtained after injection molding.Therefore, it is possible to increase the bonding accuracy when a piezoelectric vibrator is bonded using an insulating adhesive. And the small orientation, the difference in linear expansion coefficient between the piezoelectric vibrator and the insulating support plate is reduced, and the long-term reliability of the bonding part that bonds the insulating support plate and the piezoelectric vibrator is improved. It can be dramatically improved.

In the surface mount type piezoelectric oscillator of the present invention,
Although the lead terminals 4a and 4b as shown in FIGS. 1 to 5 are used, a surface mount type piezoelectric oscillator can be manufactured using the lead terminals 51a and 51b as shown in FIGS. .

That is, in the surface mount type piezoelectric oscillator shown in FIGS. 6 and 7, the projecting portions 53 of the lead terminals 51a and 51b are embedded in the insulating support plate 54, and the upper ends of the projecting portions 53 are made flat. The conductive members 57a and 57
b is connected to one end. Conductive members 57a, 57b
A connection hole 59 is formed between the surface of the insulating support plate 54 and the flat portion 55 of the protruding portion 53, and the inside thereof is filled with a conductive resin paste and cured to form the conductive members 57a, 57a.
b is formed.

In such a surface mount type piezoelectric oscillator, since the connection hole 59 does not penetrate the insulating support plate 54,
The same effects as in the above example can be obtained, and intrusion of moisture from the outside can be effectively prevented.

[0050]

EXAMPLE An Ag paste was applied to a PT-based piezoelectric ceramic (L = 2.5
mm, W = 2.0 mm, t = 0.22 mm)
As shown in FIG. 4, 300 piezoelectric vibrators 1 using the third overtone of the thickness longitudinal vibration were manufactured (oscillation frequency 3
3.86 MHz). When the anti-resonance impedance Ra and the resonance impedance Rb of the piezoelectric vibrator 1 were obtained and the P / V value was calculated, the P / V value of the tertiary overtone was 71 dB on average, and the fundamental wave and the spurious superimposed on the fundamental wave were obtained. Among them, the largest P / V value was 54 dB.

Next, the insulating support plate 2, the piezoelectric vibrator 1, and the protective plate 3 were sequentially laminated so as to form a vibration space for the piezoelectric vibrator. At this time, the vibration electrode 1 of the piezoelectric vibrator 1
The piezoelectric vibrator 1 and the insulating support plate 2 and the protection plate 3 are bonded with an epoxy adhesive around the outer circumferences of
A laminate of layers is formed, and Ag paste is filled in the connection holes 15a and 15b of the insulating support plate 2 as shown in FIG. 4, and the lead terminals 4 are formed as shown in FIGS.
Electrical connection was made between a and b and the vibrating electrodes 11 and 12 of the piezoelectric vibrator 1, and 300 surface-mount type piezoelectric vibrators of 33.86 MHz of the present invention were manufactured.

The material of the insulating support plate 2 is made of potassium titanate whiskers (fiber average diameter 0.4 μm, average fiber length 15 μm) based on wholly aromatic polyester resin.
A composite resin having a composite of 0% by weight was used.

At this time, the P / V value of the third-order overtone is 70 dB on average, and the largest P / V value of the fundamental wave and the spurious vibration superimposed on the fundamental wave is 21 dB. By doing so, it was confirmed that the P / V value of the fundamental wave can be significantly reduced while maintaining the P / V value of the third-order overtone.

On the other hand, 300 surface mount type piezoelectric oscillators of a comparative example having a three-layer structure in which lead terminals were formed by sputtering on the side wall portions of the conventional structure were manufactured. The P / V value of the third overtone at this time is 70 dB on average,
No difference from the P / V value of the surface mount type piezoelectric oscillator of the present invention was observed.

These surface-mounted piezoelectric oscillators were reflow-soldered on a printed wiring board, and the rate of change of the oscillation frequency was examined. The change rate of the oscillation frequency is F ₁ −F ₂
/ Was determined by the equation of F _1. As a result, the rate of change of the surface-mount type piezoelectric oscillator of the present invention was 55 ppm on average, while that of the surface-mount type piezoelectric oscillator of the comparative example showed a large change of 175 ppm. Incidentally, F _1, the oscillation frequency after elapse of 24 hours after the solder fixing, F ₂ indicates the oscillation frequency before the solder fixed.

Next, in a state where the surface-mount type piezoelectric oscillator is fixed to the printed wiring board by soldering, at −40 ° C. and + 125 ° C.
After performing a heat cycle of repeating 500 times,
As a result of evaluating the P / V value of the tertiary overtone in a humidity atmosphere of 75 ° C. and 75%, the change of the P / V value was within 2 dB in the surface-mount type piezoelectric oscillator of the present invention. In the surface-mount type piezoelectric oscillator having the conventional structure, there are 24 P / V values having a change of 20 dB or more, and the P / V value of the third overtone after the heat cycle is 50 dB or less. There were 18 things. Thus P
When the / V value falls below 50 dB, oscillation stops.

As a result of immersing the oscillator of the comparative example, whose P / V value was reduced by 20 dB or more, in a Lettsch check solution, a Lettsch check was performed between the piezoelectric vibrator, the insulating support plate, the protection plate and the adhesive. Liquid penetration was confirmed. Thereby, it was confirmed that the P / V value was reduced due to the loss of the sealing property.

[0058]

According to the surface mount type piezoelectric oscillator of the present invention, it is possible to reduce the size and height and to maintain the P / V value of the third harmonic at a high value while maintaining the P / V value of the fundamental wave. The V value can be suppressed small. In addition, the reliability of the solder joint between the printed wiring board and the lead terminals can be significantly improved, the fluctuation of the oscillation frequency is small even after mounting on the printed wiring board, and the piezoelectric vibrator is also used in the heat cycle. The upper and lower protective plates can be prevented from peeling off with an insulating adhesive for bonding the insulating support plate,
The reliability against the use environment in high humidity can be improved.

[Brief description of the drawings]

FIG. 1 is an external perspective view showing a surface mount type piezoelectric oscillator of the present invention.

FIG. 2 is a longitudinal sectional view taken along line AA of FIG.

FIG. 3 is a cross-sectional view taken along line BB of FIG. 2;

FIG. 4 is an exploded perspective view showing the surface mount type piezoelectric oscillator of the present invention.

FIG. 5 is a perspective view showing a lead terminal of FIG. 1;

FIG. 6 is a diagram showing a displacement distribution diagram by FEM simulation of fundamental wave vibration.

FIG. 7 is a longitudinal sectional view of another surface mount type piezoelectric oscillator of the present invention.

FIG. 8 is a transverse sectional view taken along line CC of FIG. 7;

FIG. 9 is an oscillation circuit diagram of the surface mount type piezoelectric oscillator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Piezoelectric vibrator 2 ... Insulating support plate 3 ... Protective plate 4a, 4b ... Lead terminal 5 ... Insulating adhesive 7 ... Piezoelectric substrate 11, 12 ... Vibration Electrodes 11a to c, 12a: Lead electrode 15: Connection hole 17: Conductive member 21: Projecting portion 25: Both ends of lead terminal

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H03B 5/32 H03B 5/32 H

Claims (3)

[Claims] An insulating support plate provided on a bottom surface of the insulating support plate;
And two lead terminals having protruding portions protruding toward the inside of the insulating support plate, and disposed on the insulating support plate and formed opposite to the center of both main surfaces of the piezoelectric substrate, respectively. A piezoelectric vibrator having a pair of vibrating electrodes, an extraction electrode connected to the pair of vibrating electrodes, the piezoelectric vibrator extending from the bottom surface of the piezoelectric substrate, and a protection plate disposed on the piezoelectric vibrator. Connecting the protruding portion of the lead terminal and the lead-out electrode with a conductive member in a connection hole formed in a thickness direction of the insulating support plate, and a piezoelectric substrate around the vibrating electrode. Wherein the insulating support plate and the protective plate are bonded to both main surfaces via an insulating adhesive, respectively. 2. The surface mount type piezoelectric oscillator according to claim 1, wherein both end portions of the lead terminal are bent along side surfaces of the insulating support plate. 3. When the distance between the end of the piezoelectric substrate and the vibrating electrode is x, the conductive member is located between x / 3 and 2x / 3 from the end of the piezoelectric substrate.
3. The surface mount type piezoelectric oscillator according to claim 1, wherein the surface mount type piezoelectric oscillator is connected to an extraction electrode in the range of (1).