JP2001156580A - Surface mount type piezoelectric oscillator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface mount type piezoelectric oscillator that can decrease only a P/V value of fundamental wave vibration while keeping a P/N value to be high and drastically enhance the reliability of soldering with an external device with less fluctuation in an oscillated frequency and high reliability to resistance to an operating environment under a high humidity. SOLUTION: An insulating support board 2 and a capacitor 3 are adhered to both major sides of a piezoelectric substrate 7 in an outer surrounding of vibration electrodes 11, 12 via an insulating adhesive 5, projections 21 of lead terminals 4a, 4b are exposed in connection recessed part 15a-15d of a face of the insulating support board 2 toward a pizoelectric vibrator 1 and conductor member 17a-17d in the connection recessed parts 15a-15d electrically interconnect the projections 21, the vibration electrodes 11, 12 of the piezoelectric vibrator 1 and electrodes 27, 29a, 30a of the capacitor 3.

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 having a built-in load capacitance.

[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 amplification circuit including 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 resonators 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 capacitor element having two capacitance components. There are different uses depending on the purpose of use and method of use.

In recent years, as devices have become smaller and thinner, for example, when they are incorporated into smaller and thinner devices such as HDDs and CD-ROMs, a load capacity with a small number of components is built in when mounted on a printed wiring board. Many types are used, and are further divided into two types, lead pin type and surface mount type. At present, from high-density automatic mounting technology to printed wiring boards, printed wiring boards are used together with other electronic components. A surface mount type piezoelectric oscillator capable of reflow soldering 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 oscillator, protective plates are disposed on the upper and lower surfaces of the piezoelectric oscillator, and two load capacitance components are formed on one of the protective plates. Bonded via an adhesive layer, and formed on the side wall portion two external terminal electrodes for establishing conduction between the internal electrode and the two load capacitance components, and one external terminal electrode for taking a ground-side electrode. 2. Description of the Related Art A piezoelectric oscillator having a three-layer structure is known (see, for example, Japanese Patent Application Laid-Open No. 4-189011).

[0011]

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.

There is another problem that the oscillation frequency is greatly changed by the stress acting on the piezoelectric vibrator due to the solder joining.

Further, when a heat cycle in which the temperature is repeatedly increased and decreased is performed, mechanical and thermal stresses associated with the solder bonding between the printed wiring board and the external electrodes are repeatedly applied to the surface-mount type piezoelectric oscillator. As a result, a large stress is concentrated on the adhesive layer for fixing the piezoelectric vibrator and the protective plate disposed on the upper and lower surfaces of the piezoelectric vibrator, and in the worst case, there is a possibility that the protective plate is peeled off from the piezoelectric vibrator. there were. 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. .

Furthermore, when manufacturing a surface mount type piezoelectric oscillator having a built-in load capacitance, the insulating support plate, the piezoelectric oscillator, and the capacitor are fixed with an adhesive, so that the piezoelectric oscillator is There is a problem that the tolerance of the oscillation frequency greatly varies due to the superposition of the variation of the oscillation frequency, the variation of the capacitance, and the variation due to the sticking force. As a result, a surface mount type piezoelectric oscillator having a narrow frequency tolerance could not be manufactured stably.

According to the present invention, a surface mount type piezoelectric oscillator capable of reducing only the P / V value of the fundamental wave vibration while maintaining the P / V value of the tertiary overtone at a high value and capable of reducing the size and height. The purpose is to provide a soldering element, and furthermore, the reliability of the solder joint with the outside can be dramatically improved,
Oscillation frequency is small even after mounting on a printed wiring board, eliminating peeling of the insulating support plate and capacitor from the piezoelectric vibrator even in the heat cycle. It is an object of the present invention to provide a surface-mount type piezoelectric oscillator that can be manufactured stably even when the tolerance of the piezoelectric element is narrow.

[0016]

According to the present invention, there is provided a surface-mount type piezoelectric oscillator, comprising: an insulating support plate; two lead terminals integrally provided on a bottom surface of the insulating support plate; And a piezoelectric vibrator formed by forming a pair of vibrating electrodes at the center of both main surfaces of the piezoelectric substrate, and forming electrodes on both surfaces of the dielectric substrate while being disposed on the piezoelectric vibrator. And a capacitor formed by bonding the insulating support plate and the capacitor to both main surfaces of the piezoelectric substrate around the vibrating electrode via an insulating adhesive. A connection recess is provided on the surface of the conductive support plate on the piezoelectric vibrator side, and a protrusion is provided on each of the lead terminals,
In the connection concave portion, the protrusion of the lead terminal is exposed, and the conductive member filled in the connection concave portion includes the protrusion of the lead terminal, the vibration electrode of the piezoelectric vibrator, and the capacitor. The electrodes are electrically connected.

Here, the extraction electrodes respectively connected to the pair of vibration electrodes of the piezoelectric vibrator extend on the bottom surface of the piezoelectric substrate, and the capacitor is formed on the surface of the dielectric substrate on the piezoelectric vibrator side. A common electrode, and a pair of capacitance electrodes formed to face the common electrode, and an extraction electrode connected to the common electrode extends to a bottom surface of the piezoelectric substrate and is connected to the capacitance electrode. An electrode is connected to the extraction electrode connected to the vibration electrode, and the conductive member in the connection concave portion causes the protrusion of the lead terminal to be connected to the extraction electrode of the piezoelectric vibrator.
Preferably, the common electrode of the capacitor is connected to an extraction electrode.

By employing such a structure, a three-layer structure in which an insulating support plate having two lead terminals integrally formed on both surfaces of a piezoelectric vibrator and a capacitor is bonded via an insulating adhesive. And the height can be reduced.

In the surface mount type piezoelectric oscillator of the present invention, a capacitor is disposed on the outermost surface, and a capacitor electrode facing the common electrode is formed on the surface of the capacitor. By performing trimming with a laser or the like, the load capacitance value changes, the oscillation frequency can be adjusted, and the tolerance of the oscillation frequency can be narrowed.

Further, the protrusion of the lead terminal is electrically connected to the vibrating electrode of the piezoelectric vibrator and the electrode of the capacitor by the conductive member filled in the connecting recess formed in the thickness direction of the insulating support plate. Therefore, it is possible to easily and stably make an electrical connection, and it is possible to eliminate the stop of the oscillation due to the disconnection between the vibration electrode, the capacitor electrode, the common electrode and the lead terminal.

Further, since the protrusion of the lead terminal is provided integrally with the insulating support plate, a through hole is provided in the thickness direction of the insulating support plate, and the protrusion is inserted into the through hole. As compared with the case where the conductive member is filled in the through-hole, there is no path for moisture to enter from the outside, so that the sealing performance can be improved and the device can be used stably even in a humid environment.

Preferably, 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.

Further, even when a heat cycle in which the temperature is repeatedly increased and decreased is applied to the surface mount type piezoelectric oscillator fixed to the printed wiring board with solder, the stress is relaxed by the deformation of the lead terminals. In addition, the stress applied to the entire surface mount type piezoelectric oscillator is greatly reduced, and peeling at the bonding portion between the weakest piezoelectric oscillator, the capacitor, 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.

[0024]

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 is a piezoelectric vibrator, 2 is an insulating support plate, 3 is a capacitor, 4a and 4b are lead terminals, and 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 capacitor 3 is adhered on the piezoelectric vibrator 1 via an insulating adhesive 5.

As shown in FIG. 4, the piezoelectric vibrator 1 has a pair of vibrating electrodes 1 at the center of both main surfaces of the piezoelectric substrate 7.
1 and 12 are formed facing each other. In FIG. 4, the illustration of the insulating adhesive 5 is omitted.

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 left end by an extraction electrode 11a. A vibration electrode 12 formed at the center of the lower surface side main surface of the piezoelectric substrate 7 is provided with an extraction electrode 12a.
To the right end.

The vibrating electrodes 11 and 12 and the extraction electrode 11
a and 12a are formed of, for example, a thin-film conductor film mainly composed of an Ag-based material.

The insulating support plate 2 may be made of any material as long as it has insulating properties. 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, as shown in FIGS. 2 and 3, the connecting recess 1 is formed on the surface of the insulating support plate 2 on the side of the piezoelectric vibrator 1.
5a to 15d are formed, and these connection recesses 1 are formed.
The protrusions 21 of the lead terminals 4a, 4b provided from the back surface side of the insulating support plate 2 are exposed at 5a to 15d, and A inside the connection recesses 15a to 15d is provided.
The conductive member 1 is filled with a conductive resin paste in which a conductive metal powder such as g is mixed with an epoxy adhesive, and is hardened.
7a to 17d are formed.

The capacitor 3 has a common electrode 27 formed on the surface of the dielectric substrate 25 on the side of the piezoelectric vibrator.
And a pair of capacitance electrodes 29a and 30a are formed to be exposed on the surface. The extraction electrodes 31 a and 32 a are connected to both ends of the common electrode 27, and extend to both end surfaces of the dielectric substrate 25. These extraction electrodes 31a, 3
2a extend to the extraction electrodes 31c and 32c on the bottom surface thereof via the side extraction electrodes 31b and 32b formed on the side surface of the piezoelectric substrate 7, respectively.
c, 17d.

The extraction electrodes 29b and 30b are connected to the capacitance electrodes 29a and 30a, respectively.
The extraction electrode 11 connected to the vibrating electrodes 11 and 12 via the side extraction electrodes 29c and 30c formed on the side surfaces of the extraction electrode 11b.
a, 12a. The capacitance electrodes 29a, 3
On 0a, a comb-shaped electrode is formed to adjust the capacitance,
This part may be trimmed.

Extraction electrode 11a connected to vibration electrode 11
Is a side surface extraction electrode 11c formed on the side surface of the piezoelectric substrate 7.
, And extends to the extraction electrode 11d on the bottom surface of the piezoelectric substrate 7, and the extraction electrode 11d is connected to the conductive member 17d. Further, the extraction electrode 1 connected to the vibration electrode 12
2a is connected to the conductive member 17a.

The extraction electrodes 11c and 29c on the side surfaces of the piezoelectric substrate 7 and the dielectric substrate 25 are 31b and 32, respectively.
b is formed of, for example, a conductive film made of an Ag-based thin film formed by printing, thermosetting, sputtering, or the like of a conductive paste mainly containing an Ag-based material.

In the surface mount type piezoelectric oscillator configured as described above, the insulating support plate 2 and the capacitor 3 are bonded to the outer peripheral portions of the vibration electrodes 11 and 12 of the piezoelectric substrate 7 by the insulating adhesive 5. The vibration electrode 11 of the piezoelectric vibrator 1
By forming a vibration space at 12 and its vicinity, 3
While maintaining the P / V value of the second harmonic at a high value, the fundamental wave P
/ V value can be suppressed small, and a reduction in size and height can be achieved.

In the surface-mount type piezoelectric oscillator of the present invention, as shown in FIG. 5, when mounted on the printed wiring board 41, the solder 43 melted by reflow has bent the lead terminals 4a and 4b. The solidification and shrinkage due to cooling at the portions cause tensile stress to be generated at both ends 45 of the lead terminals 4a and 4b, but the both ends 45 of the bent lead terminals 4a and 4b are bonded to the side surfaces of the insulating support plate 2. Because there is no
Both ends 45 of the lead terminals 4a and 4b are deformed by the generation of the tensile stress, and the stress is relieved. Therefore, the piezoelectric vibrator 1
The reliability of the solder connection between the piezoelectric vibrator 1 and the printed wiring board 41 can be dramatically improved, and the solder vibrator causes almost no stress to act on the piezoelectric vibrator 1 and greatly reduces the rate of change of the oscillation frequency. Can be.

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 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 1 filled in the connecting recesses 15a to 15d formed in the thickness direction of the insulating support plate 2
7a to 17d, the protrusions 2 of the lead terminals 4a to 4d
1 and the extraction electrodes 12a, 31c, 32c, and 11d are electrically connected to each other, so that an easy and stable electrical connection is possible. Oscillation due to disconnection between the vibration electrode, the capacitance electrode, the common electrode, and the lead terminal. Can be eliminated, and since there is no route for moisture to enter from the outside, the sealing performance can be further improved, and the device can be used stably even in a humid environment.

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.

Therefore, the region other than the vibrating electrode of the piezoelectric vibrator and its vicinity, the insulating support plate and the capacitor are fixed with an insulating adhesive, and a vibrating space is formed in the vibrating electrode of the piezoelectric vibrator and its vicinities. As a result, a small and low-profile surface-mount type piezoelectric oscillator capable of suppressing the P / V value of the fundamental wave to a small value while maintaining the P / V value of the third harmonic at a high value is obtained. In addition, the reliability of the external terminals and solder joints is dramatically improved, and the oscillation frequency does not fluctuate even after mounting on the printed wiring board.Furthermore, even during the heat cycle, the piezoelectric vibrator, insulating support plate, and capacitor Eliminating the peeling of the adhesive layer to fix the device, increasing the reliability of the environment for use in high humidity, and adjusting the capacitance by trimming the electrode that forms the load capacitance, narrowing the tolerance of the oscillation frequency. A surface-mounted piezoelectric oscillator can be obtained.

[0044]

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.

The Ag paste is applied to a BaTiO ₃ dielectric ceramic (L = 2.5 mm, W = 2.0 mm, t = 0.3 mm)
To form a capacitor having a common electrode 27 and capacitor electrodes 29a and 30a as shown in FIG.

Next, the insulating support plate 2, the piezoelectric vibrator 1, and the capacitor 3 were sequentially laminated so as to form a vibration space of the piezoelectric vibrator. At this time, the piezoelectric vibrator 1, the insulating support plate 2, and the capacitor 3 are adhered to the outer periphery of the vibrating electrodes 11 and 12 of the piezoelectric vibrator 1 with an epoxy-based adhesive to form a three-layer laminate. At the same time, as shown in FIG. 4, Ag is formed in the connection concave portions 15a to 15d of the insulating support plate 2.
The paste is filled, and as shown in FIGS. 2 and 3, the protrusions 21 of the lead terminals 4a, 4b and the extraction electrodes 12a, 31
Electrical connection was performed with c, 32c, and 11d. 300 such 33.86 MHz surface mount type piezoelectric oscillators 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) with respect to the 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 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 on the side wall portions by sputtering in a 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 subjected to reflow soldering 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 50 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.

The oscillator of the comparative example, in which the P / V value was reduced by 20 dB or more, was immersed in a Lettsch check solution. As a result, the Lettsch check solution was interposed between the piezoelectric vibrator, the insulating support plate, the capacitor, and the adhesive. Was confirmed. Thereby, it was confirmed that the P / V value was reduced due to the loss of the sealing property.

Further, in the above-mentioned sample, it was found that when the capacitance electrode was trimmed and the capacitance value of the load capacitance C1 was reduced by ₁ pF, the oscillation frequency was shifted to a high frequency side of about 150 ppm. Therefore, the allowable range of the load capacity is 8
Considering changing the load capacitance value from pF to 20 pF, it is possible to shift the oscillation frequency up to about 1800 ppm toward the high frequency side.

That is, when the generated frequency is shifted to a lower frequency side than the target oscillation frequency, the desired oscillation frequency can be matched by trimming the capacitor electrode.
Therefore, a surface-mount type piezoelectric oscillator having a built-in load capacitance and having a low profile, high reliability, and high accuracy of oscillation frequency having a three-layer structure can be obtained.

[0055]

According to the surface mount type piezoelectric oscillator of the present invention, the P / V value of the fundamental wave can be suppressed small while the P / V value of the third overtone is maintained at a high value. The size and height can be reduced. Furthermore, the reliability of the solder joint between the printed wiring board and the lead terminals can be greatly improved, the fluctuation of the oscillation frequency is small even after mounting on the printed wiring board, and the piezoelectric vibrator and its The peeling of the insulating adhesive for bonding the upper and lower capacitors and the insulating support plate can be prevented, and the reliability against the use environment in high humidity can be improved.
Even when the tolerance of the oscillation frequency is narrowed, it can be manufactured stably.

[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 cross-sectional view showing a state where the surface-mount type piezoelectric oscillator of the present invention is mounted on a printed circuit board.

FIG. 6 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 ... Capacitor 4a, 4b ... Lead terminal 5 ... Insulating adhesive 7 ... Piezoelectric substrate 11, 12 ... Vibration electrode 11a, 11c, 11d, 12a, 29b, 29c, 3
0b, 30c, 31a, 31b, 31c, 32a, 32
b, 32c ... lead-out electrodes 15a to 15d ... connection concave parts 17a to 17d ... conductive members 21 ... protruding parts 25 ... dielectric substrate 27 ... common electrodes 29a, 30a ... Capacitance electrode 45: Both ends of lead terminal

Claims (3)

[Claims] An insulating support plate; a lead terminal integrally provided on a bottom surface of the insulating support plate; and a pair of lead terminals disposed on the insulating support plate and disposed at the center of both main surfaces of the piezoelectric substrate. A piezoelectric vibrator formed with a vibrating electrode, and a capacitor disposed on the piezoelectric vibrator and having electrodes formed on both surfaces of a dielectric substrate; The insulating support plate and the capacitor are respectively bonded to both main surfaces of the piezoelectric substrate via an insulating adhesive, and further, a connection recess is formed on a surface of the insulating support plate on the side of the piezoelectric vibrator, Each of the lead terminals is provided with a protruding portion. The protruding portion of the lead terminal is exposed in the connection recess, and the conductive member filled in the connection recess is provided with the protruding portion of the lead terminal and the piezoelectric member. Vibrator vibrating electrode,
A surface mount type piezoelectric oscillator, wherein an electrode of the capacitor is electrically connected. An extraction electrode connected to each of a pair of vibration electrodes of the piezoelectric vibrator extends on the bottom surface of the piezoelectric substrate, and a capacitor is formed on a surface of the dielectric substrate on the piezoelectric vibrator side. An electrode, and a pair of capacitance electrodes formed to face the common electrode, and an extraction electrode connected to the common electrode extends to the bottom surface of the piezoelectric substrate, and is connected to the capacitance electrode. Is connected to an extraction electrode connected to the vibration electrode, and the protrusion of the lead terminal is connected to the extraction electrode of the piezoelectric vibrator and the extraction electrode of the common electrode of the capacitor by a conductive member in the connection recess. 2. The surface mount type piezoelectric oscillator according to claim 1, wherein 3. The surface mount type piezoelectric oscillator according to claim 1, wherein both ends of the lead terminal are bent along side surfaces of the insulating support plate.