JPH0998049A - Piezoelectric parts - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the position accuracy of a piezoelectric parts when it is assembled by connecting electrically the inner electrodes to the outer electrodes and also connecting a piezoelectric resonator to the inner electrodes at about the center part of the resonator via conductive adhesive. SOLUTION: A 1st cover body 14A and a 2nd cover body 14B have flat shapes. The inner electrodes 12 are formed on a main inner surfaces 14a of both bodies 14A and 14B, i.e., a part including a center part serving as a connection surface to a piezoelectric resonator 11. Then the outer electrodes 13 are formed at a part of the main outer surfaces 14b, i.e., the partial side surfaces of both bodies 14A and 14B and the surface counter to the connection surface of the resonator 11. Both electrodes 12 and 13 are connected electrically to each other. The electrodes 12 which are formed on both bodies 14A and 14B are connected to the resonator 11 at about the center part of the resonator 11 via round conductive adhesive 15 having the prescribed thickness and a prescribed adhesion area.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric component, and more particularly to a communication device such as a cordless telephone or a radio, a household microcomputer, a printer which is an information peripheral device,
And a piezoelectric component used as a reference signal generating piezoelectric resonator (oscillator) in an infrared remote controller or the like.

[0002]

2. Description of the Related Art There are various types of vibration modes of piezoelectric components, and these vibration modes have a range of frequencies suitable for each. For example, in the case of a frequency of about 190 to 2000 kHz, the spreading vibration mode is used,
The thickness shear vibration mode is used in the case of a frequency of about Hz to 10 MHz, and the energy trap type thickness longitudinal vibration mode is often used in the case of a frequency of about 2.5 to 30 MHz.

Generally, an oscillator is represented as shown in FIG. 12 regardless of the vibration mode used. A positive feedback Colpitts type oscillation circuit as shown in FIG. 13 is configured using a ceramic oscillator or a crystal oscillator, and a Colpitts type oscillation circuit using a ceramic oscillator uses an inverter as shown in FIGS. 14 and 15. The configuration that was used is the most common. FIG. 16 shows the method of use in an actual oscillator circuit. In FIG. 16, a pair of capacitors CL is provided outside the oscillator X.
₁ , CL ₂ and the two resistors Rt and Rd are connected, the INV. 1 and INV. Connected to 2. IN
V. 1 acts as an inverting amplifier of the oscillation circuit, and INV.
2 functions as a buffer and a waveform shaping circuit.

FIG. 17A is a schematic perspective view showing a piezoelectric component utilizing a thickness shear vibration mode, FIG. 17B is an exploded perspective view thereof, and FIG. 17C is for explaining a piezoelectric resonator mounting portion. 3 is a schematic partially exploded perspective view of a portion excluding the cover body of FIG.

The piezoelectric component 70 includes a cover body 71, a substrate 72, and a piezoelectric resonator 73 arranged on the substrate 72. The piezoelectric resonator 73 has a piezoelectric substrate 73a and a part of both main surfaces thereof. And an electrode 73b formed on. Strip-shaped (for input / output) terminal electrodes 74 are formed at predetermined two locations on the substrate 72.
Conduction with the electrode 73b is achieved at both ends of the.
Further, an earth electrode 75 is formed in an intermediate position between the terminal electrodes 74, 74 on the substrate 72 so as not to contact the electrode 73b in parallel with the terminal electrode 74.

In the piezoelectric component 70 thus constructed, the entire piezoelectric resonator 73 vibrates in the thickness shear vibration mode. Further, it is not necessary to form an electrode on the cover body 71, and the cover body 71 has a simple structure as a whole.

Further, in the piezoelectric component 70, the ground electrode 75
A capacitance is formed between the terminal electrode 74 and the terminal electrode 74, and the external capacitance is incorporated inside. This is possible because the required capacitance value is as small as several tens (pF). This equivalent circuit is shown in FIG.

FIG. 19 (a) is a schematic perspective view showing a piezoelectric component utilizing the energy trap type thickness longitudinal vibration mode, and FIG. 19 (b) is an exploded perspective view thereof.

The piezoelectric component 90 includes a first cover body 91a, a second cover body 91b, and a piezoelectric substrate 92, and a circular vibration electrode is provided at substantially the center of both main surfaces of the piezoelectric substrate 92. 93 is formed. In addition, the first cover body 9
Terminal electrodes 94 are formed on both ends of the piezoelectric substrate 9a, the second cover body 91b, and the piezoelectric substrate 92, respectively.
The terminal electrodes 94 formed on the second electrode 2 are connected to the circular vibrating electrodes 93, respectively.

The first cover body 91a and the second cover body 91b each have a recess 96,
The vibration of the vibration electrode 93 of the piezoelectric substrate 92 is not disturbed.

Further, the substantially central portion of the first cover body 91a is formed in a strip shape in parallel with the terminal electrode 94, and the second cover body 91b, which is connected to the strip portion after completion, and the piezoelectric substrate 9.
A ground electrode 95 is formed on the side surface and the bottom surface of No. 2.

As described above, the piezoelectric component 90 includes the circular vibrating electrode 9 between the symmetrical upper and lower cover bodies 91a and 91b.
3 has a structure in which a piezoelectric substrate 92 having 3 is sandwiched.

In the piezoelectric component 90, energy in the thickness longitudinal vibration mode that resonates between the vibrating electrodes 93 formed in the substantially central portion of the piezoelectric substrate 92 is confined without leaking out of the vibrating electrode 93. It is not necessary to store the whole in the inner space of the cover bodies 91a and 91b.

In the case of the piezoelectric component 90 as well, as in the case of the piezoelectric component 70, a capacitance is formed between the ground electrode 95 and the terminal electrode 94.

FIG. 20 is a schematic exploded perspective view showing a piezoelectric component utilizing the spreading vibration mode.

In the figure, reference numeral 101 denotes a piezoelectric resonator. The piezoelectric resonator 101 is formed by forming electrodes 101b on both main surfaces of a piezoelectric substrate 101a which is polarized in a direction perpendicular to the surface. There is. This piezoelectric resonator 101 is in a state of being pressed and sandwiched near the center of the piezoelectric resonator 101 by metal electrodes 102 and 103 having protrusions 102a and 103a at the center and lead leads 102b and 103b at the corners, respectively. Are housed in a resin case 104 and sealed with a resin cover body 105.

In the piezoelectric component 100 thus constructed, the displacement of the piezoelectric resonator 101 is maximized in the peripheral portion thereof, so that the piezoelectric resonator 101 is prevented from being disturbed in the central portion where the displacement is smallest. Must be held. Further, even when the metal electrode 102, 10 is held at the central portion where the displacement is the smallest, the holding area is minimized and the non-fixed holding is employed.
The protrusions 102a and 103a provided on the No. 3 are small hemispherical shapes, and the surfaces thereof are substantially flat. Further, in order to secure the clamping pressure, the metal electrode 102 is curved in an arc shape, and has a structure in which a spring function is added. Further, when the periphery of the piezoelectric resonator 101 comes into contact with the inner wall 104a of the case 104, the resonance is similarly disturbed. Therefore, not only the pinching position should be accurately centered, but also the rotation deviation should be minimized. It is assembled. Further, the piezoelectric resonator 101 is connected to the metal electrodes 102, 10
The case 104 and the cover body 10 in a state of being sandwiched by 3
Since it is stored in 5, the case 104 and the cover body 10
A reaction force of the clamping force acts on 5, and the adhesive portion 104b needs to have a sufficient area for securing strength, and the case 104 and the cover body 105 need to be thick and sturdy as a whole. There is.

As described above, the external capacitance of the piezoelectric component utilizing the spreading vibration mode is generally several tens to several hundreds (p.
F) is required, and a capacitor, a resistor, and an IC are connected to function as an actual oscillation circuit.

[0019]

As described above, the piezoelectric component 100 of the spreading vibration mode described above is found in the piezoelectric component utilizing other vibration modes (thickness sliding vibration mode, energy trapping type thickness longitudinal vibration mode). The following problems arise because a stable and strong support structure for the piezoelectric resonator cannot be realized.

(1) Since it is not possible to fix the piezoelectric resonator 101 and the metal electrodes 102 and 103 at the time of assembly, it is possible to assemble the piezoelectric resonator 101 with the XY position and the rotational position accurately at the same time. Have difficulty.

(2) Piezoelectric resonator 101 as a component
Metal electrodes 102, 103, case 104, cover body 1
05 at least 5 points are required, and the metal electrode 102,
Since there is no symmetry between the parts 103 and between the case 104 and the cover body 105, at least five kinds of parts are required.
There are many types of parts and the cost is high, and assembly is troublesome.

(3) It is necessary to bend the lead-out leads 102b and 103b for surface mounting.

(4) The piezoelectric resonator 101 is the metal electrode 10
Since it is held only by the spring-like pressing force of 2, 103, the displacement easily occurs due to an impact such as a drop.

(5) In order to secure the strength of the case 104 and the cover body 105, it is necessary to increase the thickness of each of them, and it is difficult to reduce the size because the area and height of the parts are large. .

(6) In order to enable stable oscillation in the piezoelectric component 100, the external capacitance should be approximately 100.
Although it is necessary to set the pF to about 300 pF, the capacity cannot be built in the case 104 made of resin.

The present invention has been made in view of the above problems, and it is possible to easily increase the position accuracy of the piezoelectric resonator at the time of assembly, the number of parts and the kind of parts are small, and it is possible to easily cope with the surface mounting and to receive an impact. On the other hand, it is an object of the present invention to provide a small-capacity built-in type piezoelectric component that not only exhibits stable characteristics but also has a low component height.

[0027]

In order to achieve the above object, a piezoelectric component (1) according to the present invention comprises a piezoelectric resonator having electrodes on both surfaces of a piezoelectric substrate, and the piezoelectric resonator. A case for accommodating, and an internal electrode is formed on a part including a central portion of both inner main surfaces of the case, while an external electrode is formed on an outer surface of the case, and the internal electrode and the external electrode are formed. Is electrically connected, and the piezoelectric resonator and the internal electrode are connected to each other by a conductive adhesive at a substantially central portion of the piezoelectric resonator.

According to the above-described piezoelectric component (1), the conductive adhesive is used to support the piezoelectric resonator instead of the conventional protrusion, and the suppression of vibration of the piezoelectric resonator due to holding is minimized. It is possible to surely prevent the positional deviation while suppressing it to the limit, and the assembly becomes easy. Further, since both the internal electrode and the external electrode are formed on the case itself and the functions of the conventional external lead electrode (lead) and the internal terminal (metallic electrode) are added, the metallic electrode is provided separately. It is not necessary to reduce the number of parts. Further, the assembled piezoelectric component can be surface-mounted as it is by the external electrodes provided on the case itself. Further, since it is not necessary to press and sandwich the piezoelectric resonator, the thickness of the case can be minimized, and the area required for adhesive fixing of the case can be reduced, so that the size can be reduced.

A piezoelectric component (2) according to the present invention is the piezoelectric component described in (1) above, wherein the case is a flat plate-shaped first cover body, a second cover body and a frame-shaped space. Of the first cover body and the second cover body, the internal electrode is formed on a part of the first cover body and the second cover body including the central portion of the connection surface with the piezoelectric resonator. The external electrode is formed on a part of a side surface of the second cover body or a part of a side surface and a surface facing the connection surface.

According to the above-mentioned piezoelectric component (2), since the first cover body and the second cover body can have a symmetrical structure, the same shape is used as each component before assembly. It is possible to reduce the number of types of parts. Further, the frame-shaped spacer makes it possible to easily complete the sealing structure by adhesively fixing the piezoelectric resonator inside the frame to the first cover body or the second cover body. it can. Further, the formation position of the external electrode is part of the side surface of the first and second cover bodies, or part of the side surface and part of the surface facing the connection surface,
That is, since it is a part of the side surface or a part of the side surface and a part of the outer main surface of the completed product, it is possible to easily establish electrical connection with the outside.

A piezoelectric component (3) according to the present invention is the piezoelectric component described in (2) above, wherein the external portion formed on the first cover body is formed on a part of an outer surface of the spacer. An external electrode for electrically connecting the electrode and the external electrode formed on the second cover body is formed.

According to the piezoelectric component (3) described above, the external electrodes formed on the first cover body, the external electrodes formed on the second cover body, and a part of the outer surface of the spacer are formed. Since it is possible to achieve conduction with the external electrode formed on the board, even if the solder bonding position does not reach the external electrode formed on the cover body located above during mounting, the solder can be securely connected to the board side. Conduction can be achieved.

The piezoelectric component (4) according to the present invention is characterized in that, in the piezoelectric component described in (1) or (2) above, metal electrode terminals are provided outside the case.

According to the above-mentioned piezoelectric component (4), by providing the metal electrode terminal, the conduction with the internal electrode among the external electrodes formed on the first cover body and the second cover body is provided. It is not necessary to form one external electrode which is not formed, and the electrode formed on one cover body can be read to the other side. Therefore, it is possible to reduce the amount of expensive silver paste or the like used as the external electrode material, and it is possible to reduce the cost. Further, since it is metallic, the solder wettability is good, and the reliability of mounting can be improved. Also, by using a spring material such as phosphor bronze, it is possible to reliably fix and conduct electricity by sandwiching and fixing.

Further, the piezoelectric component (5) according to the present invention is the piezoelectric component according to any one of (1) to (3) above, including the central portions of both outer main surfaces of the case, and An electrode is formed on a part except the part where the external electrode exists,
It is characterized in that a capacitor is formed by the electrode, the internal electrode and a part of the case existing between them.

According to the above-mentioned piezoelectric component (5), since the capacitor function is added to the case in addition to the protection function and the connection terminal function to the outside, it is not necessary to separately install a capacitor, and the capacitance is increased. It is possible to reduce the size of the entire device while incorporating it in the case.

A piezoelectric component (6) according to the present invention is the piezoelectric component described in (4) above, including the central portions of both outer main surfaces of the case, and the external electrode and the metal electrode terminal. The electrode is formed in a part except the part where
It is characterized in that a capacitor is formed by the electrode, the internal electrode and a part of the case existing between them.

According to the piezoelectric component (6) described above, it is possible to obtain the effects of both the piezoelectric components described in (4) and (5) above.

[0039]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a piezoelectric component according to the present invention will be described below with reference to the drawings.

<First Embodiment> FIGS. 1A and 1B are views showing a piezoelectric component according to a first embodiment. FIG. 1A is a schematic vertical sectional view, FIG. 1B is a schematic exploded perspective view, and FIG. FIG. 3A is a schematic partial plan view and a side view thereof.

In the figure, reference numeral 11 denotes a flat plate-shaped piezoelectric resonator, and the piezoelectric resonator 11 includes a piezoelectric substrate 11a and electrodes 11b formed on both main surfaces thereof. The piezoelectric resonator 11 is hermetically held in a case 14, and the case 14 includes a first cover body 14A, a second cover body 14B, and a frame-shaped spacer 14C.

The first cover body 14A and the second cover body 14B are in the shape of a flat plate, and are the inner main surfaces 14a of the first cover body 14A and the second cover body 14B, which are the piezoelectric resonators 11 and. The internal electrode 12 is formed in a part including a central portion which is a connection surface of the first cover body 14A and the second cover body 14B, and an outer main surface which is a surface facing the connection surface. The external electrode 13 is formed on a part of the surface 14b. The internal electrode 12 and the external electrode 13 are electrically connected to each other, and the piezoelectric resonator 11 and the first cover body 14A
And the internal electrodes 12 formed on both the second cover body 14B are connected to each other by a conductive adhesive 15 having a circular shape and a predetermined thickness and a bonding area at a substantially central portion of the piezoelectric resonator 11. Between the first cover body 14A and the second cover body 14B, a frame-shaped spacer 14C having a space portion 14c having a width capable of accommodating the piezoelectric resonator 11 in the central portion.
Are arranged, and the first cover body 14A, the second cover body 14B, and the frame-shaped spacer 14C are made of an epoxy resin or the like having high adhesive strength in a state where the piezoelectric resonator 11 is housed in the void portion 14c. It is firmly bonded with a non-conductive adhesive. Further, it is desirable that the conductive adhesive 15 has elasticity, and the first cover body 14A and the second cover body 1 are
It is desirable that the piezoelectric resonator 11 is pressed and held in a state where the pressing force from both internal electrodes 12 of 4B is slightly absorbed by the conductive adhesive 15.

As described above, in the piezoelectric component 10 according to the first embodiment, the conductive adhesive 15 is used for conducting the electrode 11b provided on the piezoelectric resonator 11 and the internal electrode 12 and for holding and fixing the piezoelectric resonator 11. Has been secured. Further, the piezoelectric resonator 11 is parallel to the first cover body 14A and the second cover body 14B, and in order not to disturb the resonance and suppress the resonance by contacting the periphery of the piezoelectric resonator 11 with the inner wall of the case 14. Each side of the piezoelectric resonator 11 is arranged so as to be parallel to each side of the frame-shaped spacer 14C. Further, it is desirable that the conductive adhesive 15 is applied at an appropriate position and amount so as to be applied in the vicinity of the center of the piezoelectric resonator 11 so as to prevent disturbance and suppression of the resonance of the piezoelectric resonator 11. If the coating amount is less than the appropriate amount, the holding strength of the piezoelectric resonator 11 may be insufficient and the piezoelectric resonator 11 may drop off. On the other hand, if the amount is more than the appropriate amount, the resonance of the piezoelectric resonator 11 is suppressed and desired resonance characteristics are obtained. May not be obtained.

Further, the larger the difference between the outer dimension L ₁ and the inner dimension L _{2 on one} side of the frame-shaped spacer 14C, the wider the bonding area with the cover body, so the outer dimension L _{1 of the} spacer 14C is as long as the dimension allows. It is desirable to increase the contact area and the adhesion area. Generally, the difference between the inner dimension L ₂ and the outer dimension L ₁ is 0.
It is suitable to be about 5 to 1.5 mm.

In manufacturing the piezoelectric component 10 having the above-described structure, first, for example, a conductive adhesive 15 of a predetermined size is formed on the central portion of the inner main surface 14a of the first (second) cover body 14A (14B) made of alumina. After plate-printing and bonding the piezoelectric resonator 11 at a predetermined position, the piezoelectric resonator 11 becomes the first (second)
The conductive adhesive 15 is cured while maintaining a predetermined gap so as not to come into contact with the cover body 14A (14B). Next, another cover body 14B (14A) similarly printed with a conductive adhesive 15 and a frame-shaped spacer 14C made of, for example, alumina, printed with a non-conductive adhesive on both surfaces are shown in FIG. 1 (a). The non-conductive adhesive is cured under pressure by assembling it to the state shown in FIG.

In the frame-shaped spacer 14C, the cavity 14c is formed by die punching or laser cutting at the time of the green sheet before main firing, and the outer periphery is also cut,
After the main calcination, a flatness is secured by applying a lapping process to remove the warp.

In the piezoelectric component 10 thus constructed, the conventional projection 102 is used to hold the piezoelectric resonator 11.
Since the conductive adhesive 15 is used in place of a and 103a (FIG. 20), the positional displacement due to the adhesive fixing is surely prevented while suppressing the vibration characteristic of the piezoelectric resonator 11 by holding it to the minimum. In addition, it is easy to assemble.

Further, by the frame-shaped spacer 14C, the frame-shaped spacer 14C and the first cover body 14A or the second cover 14A or the second cover 14C in the state where the piezoelectric resonator 11 is accommodated inside the frame (void 14c). The sealing structure can be easily completed by adhesively fixing it to the cover body 14B.

Further, both the internal electrode 12 and the external electrode 13 are formed on the case 14 itself, and the conventional extraction lead 1
02b, 103b and metallic electrodes 102, 103 (see FIG. 2).
0) is added, the metallic electrode 10
It is not necessary to separately provide 2, 103, and the number of parts can be reduced.

Further, since the first cover body 14A and the second cover body 14B have a symmetrical structure, it is only necessary to produce the same shape as the respective parts, which reduces the kinds of parts. be able to.

Further, since the formation position of the external electrode 13 is a part of the side surface or a part of the side surface of the piezoelectric component 10 and a part of both main surfaces, it is possible to easily conduct electrical connection to the outside and to mount the surface mounting. Therefore, it is not necessary to dispose a lead or the like for bending.

As the binder of the conductive adhesive 15, modified urethane type, silicon type, synthetic rubber type, epoxy type and the like are considered, and a material having elasticity after curing is desirable.

The conductive filler of the conductive adhesive 15 may be a stable conductor such as silver, platinum or carbon, and the inexpensive and low resistance material may be silver.

The viscosity of the conductive adhesive 15 before curing is about 1,00.
In the range of 0 cP to 300,000 cP, when plate-making printing is used as the method of applying the conductive adhesive 15, 100,000 cP to 200,000 cP is used to maintain a stable shape during the time from application to curing. The viscosity was appropriate. However, even if the material has a lower viscosity than this, it is possible to maintain and stabilize the shape by adjusting the shape while slightly hardening it.

As the shape of the piezoelectric resonator 11, a square plate shape having good symmetry is desirable in order to smooth the impedance behavior near the resonance frequency. However, for the purpose of adjusting the frequency, the corners of the square may be slightly cut with good symmetry, or a slit may be provided at the center of the side with good symmetry.

The first cover body 14A and the second cover body 1
The shape of 4B is not limited to a square plate shape, and may be a rectangular plate shape. Since the cover bodies 14A and 14B have anisotropy between the direction in which the electrodes are taken out and the direction in which the electrodes are not taken out, a rectangular plate shape is adopted rather than the direction in which the directions can be easily determined in manufacturing, and the direction in which the electrodes are taken out is made slightly longer. For example, if it is 8 × 7 mm, it is convenient because the parts can be easily aligned according to the shape during automatic assembly. In that case, the outer shape of the frame-shaped spacer 14C is also preferably set to 8 × 7 mm, for example.

The first cover body 14A and the second cover body 1
4B does not necessarily have to have a flat plate shape, and may have a shape having a protrusion (not shown) at a location where the conductive adhesive 15 is provided. With the shape, the first cover body 1
Although it is difficult to manufacture 4A and the second cover body 14B itself, the space between the piezoelectric resonator 11 and the first cover body 14A and the second cover body 14B is secured by the height of the protrusion when assembling the components. Therefore, the efficiency of assembly can be improved.

In the first embodiment, alumina is used as the material of the case 14, but the material is not limited to this. In another embodiment, for example, a glass epoxy resin often used for an electric circuit board and a copper sheet are used. The tension electrode may be provided, and other materials such as ceramic, paper epoxy, and bakelite may be selected. In that case, problems such as warpage during firing and a decrease in production yield when manufactured from ceramics or the like do not occur, and it is considered to be rather advantageous during mass production.

In the first embodiment, a die punching process or a laser cutting process is adopted as a method of forming the frame-shaped spacer 14C, but the present invention is not limited to this, and a resin is used in another embodiment. In some cases, it may be formed by injection molding or machining.

In the first embodiment, the electrodes 11b are formed by applying the conductive paste on the entire surfaces of both surfaces of the piezoelectric resonator 11, but the present invention is not limited to this.
In another embodiment, the formation surface of the electrode 11b may not be the entire surface but may be partially formed in the central portion or the peripheral portion,
Also, gold, silver, copper, nickel, chrome, solder, tin, lead,
Electrodes may be formed by single-layer or multi-layer plating or sputtering. If the electrode 11b is rather partially formed, the amount of the electrode material used can be reduced when the electrode is formed by plating, and in the case of plating, high temperature treatment is not required, which is advantageous in manufacturing. This is effective when adjusting the resonance strength or the electrostatic capacitance of the piezoelectric resonator 11 itself.

In the first embodiment, the highly reliable silver paste is used as the electrode material for the internal electrodes 12 and the external electrodes 13, but the present invention is not limited to this, and another embodiment may use other pastes. An electrode material may be used, and in particular, since the internal electrode 12 is less likely to be exposed to moisture and less likely to be impacted, a resin frit-containing low temperature curable silver paste, carbon paste, plating or the like may be used.

In the first embodiment, the first cover body 14A and the second cover body 14B and the frame-shaped spacer 14C are adhered to each other by the epoxy non-conductive adhesive, but the present invention is not limited to this. In another embodiment, a silicone-based adhesive may be used alone or in combination with an epoxy-based adhesive or the like for the purpose of suppressing the penetration of moisture into the parts.

In the first embodiment, plate-making printing was used as the method of applying the conductive adhesive 15, but the method is not limited to this. In another embodiment, a method of placing a small amount by a dispenser, a brush or a tip is used. A method of applying using a sharp instrument may be adopted. Conductive adhesive 1 at that time
The viscosity of 5 may be selected according to the application method, and empirically, for example, in the case of using a dispenser or the like,
It is easier to apply using a conductive adhesive having a viscosity of 10,000 cP to 20,000 cP. A method based on plate-making printing is effective for stably applying an appropriate amount in a constant amount during mass production.

In the first embodiment, the case 14 includes the first cover body 14A, the second cover body 14B, and the frame-shaped spacer 1.
However, the present invention is not limited to this, and in another embodiment, in order to further reduce the number of parts and to facilitate the manufacture of the frame-shaped spacer 14C. A cover body member having a shape in which a first (second) cover body 14A (14B) and a frame-shaped spacer 14C are attached to each other is used, and the cover body member and the remaining cover body 14B are used.
The case 14 may be composed of two parts (14A). At that time, when the cover body member is manufactured from alumina or the like, for example, a green sheet on which the internal electrodes 12 and the external electrodes 13 are preliminarily printed and a green sheet having a void portion 14c like the frame-shaped spacer 14C are attached. After combining, the outer peripheral portion is cut and the main firing is performed. The thickness of the member to be fired is increased by the thickness of the first (second) cover body 14A (14B) as compared with the thickness of only the frame-shaped spacer 14C, so that the warpage during firing is reduced and It can be omitted. Further, manufacturing efficiency can be improved by reducing the number of parts by one.

<Second Embodiment> FIG. 2A is a schematic vertical sectional view showing a piezoelectric component according to a second embodiment.
(B) is a schematic longitudinal sectional view showing a state where the piezoelectric component is mounted on a mother board or the like. The components having the same functions as those in the first embodiment are designated by the same reference numerals.

Reference numeral 16 in the drawing denotes an external electrode formed on a part of the outer surface of the spacer 14C. The external electrode 16 is the external electrode 13 formed on the first cover body 14A and the second cover body 14B. The external electrode 13 formed in the above is electrically connected. Other configurations are similar to those of the first embodiment.

Further, in FIG. 2 (b), 21 indicates solder and 22 indicates a mother board. Solder 21
Thus, the piezoelectric component 20 having the above configuration is fixed and mounted on the mother board 22.

As described above, according to the piezoelectric component 20, the area of the portion having good solder wettability in the soldering portion at the time of surface mounting on the mother board 22 or the like is formed larger by the external electrode 16. The mounting reliability can be improved, and the external electrode 13 formed on the first cover body 14A, the external electrode 13 formed on the second cover body 14B, and a part of the outer surface of the spacer 14C can be formed. Since electrical continuity with the formed external electrode 16 is achieved, even if the solder bonding position does not reach the external electrode 13 formed on the upper first cover body 14A, the mother board 2
It is possible to achieve reliable electrical connection with 2.

In the second embodiment, the case where the external electrodes 13 of the first cover body 14A, the second cover body 14B and the external electrodes 16 of the spacer 14C are formed on the pair of side surfaces of the piezoelectric component 20. Although FIG. 3 (a) shows an enlarged perspective view of the main part thereof, the present invention is not limited to this, and in another embodiment, the external electrode 13 shown in FIG. 3 (a). , 16 and separate external electrodes 3 on the surface orthogonal to
1 may be formed, and in this case, the structure is such that more reliable conduction is achieved (FIG. 3 (b) shows an enlarged perspective view of the relevant part).

<Third Embodiment> FIGS. 4A and 4B are views showing a piezoelectric component according to a third embodiment. FIG. 4A is a schematic vertical sectional view, FIG. 4B is an enlarged sectional view of a main part, and FIG. ) Is a schematic vertical sectional view when mounted on a motherboard.

First cover body 14A, second cover body 1
The external electrode 13 is formed on one side of 4B and a part of the outer main surface 14b.
Are continuously formed, and the internal electrode 12 is formed on a part of the inner main surface 14a.

In the figure, reference numeral 41 denotes a metal electrode terminal having a substantially U-shaped cross section. A substantially rectangular notch 41a is formed at a predetermined position of the metal electrode terminal 41, and the notch 41a is formed. Is folded inward at an angle of 90 ° or less, and thereby has a function as a hooking portion for the case 14. The notch 41a is set such that its angle and length are in contact with the first cover body 14A or the second cover body 14B, and the metal electrode terminal 41 itself has a spring property, so that the case It also has a function of sandwiching 14 together.

The metal electrode terminal 41 configured as described above
Thus, the piezoelectric component 40 is configured by sandwiching the case 14 in which the piezoelectric resonator 11 is sealed. Other configurations are the same as those in the first embodiment.

In the piezoelectric component 40 thus constructed, the metal electrode terminal 41 is provided, so that the external electrode 13 formed on one cover body 14A (14B) is electrically connected to the other. Cover body 14B (14
We are able to lead to A). Therefore, of the external electrodes 13 formed in the case 14, it is not necessary to form one external electrode 13 that is not electrically connected to the internal electrode 12, and the amount of expensive silver paste or the like used as the external electrode material can be reduced. It can be reduced and the cost can be reduced. Further, since the metal electrode terminal 41 is metallic, the solder wettability is good, and the reliability of mounting can be improved. Further, by using a spring material such as phosphor bronze as a constituent material, it is possible to achieve reliable fixing and conduction by sandwiching and fixing.

As shown in FIG. 4, the metallic electrode terminal 41
As for the shape of the piezoelectric component 40, the external electrodes 13 formed at opposite ends of the piezoelectric component 40 can be sandwiched more than a plate or an angle bent at 90 degrees like a flat plate or an angle. The desired shape is desirable.

The spring material may be beryllium copper or the like in addition to phosphor bronze, and the metallic electrode terminal 41 may be used.
In order to improve the solder wettability and prevent oxidation, a single layer such as tin plating or silver plating or a multilayer plating combining components may be applied to the surface thereof.

In the third embodiment, the notch 41a is formed in the metallic electrode terminal 41 as the structure for ensuring the sandwiching reliability and the conduction reliability, and the hooking claw portion is used, but it is not limited thereto. Instead, in another embodiment, the metallic electrode terminal 41 may have a planar shape that is easy to manufacture, and a protrusion or the like may be provided instead of the cutout portion 41a. In addition, the external electrode 13 is provided with a sharp return claw having a sharp tip.
Alternatively, the conduction may be ensured by biting into the first and second cover bodies 14A (14B). Thereby, the first cover body 14A and the second cover body 14 of the metallic electrode terminal 41 are
The structure can be easily inserted into B, but difficult to remove.

Further, in order to fix and reliably contact the case 14 and the metal electrode terminal 41, as shown in FIG. 5, not only the notch 41a is formed, but also the case 14 and the metal electrode terminal 41 are formed. The adhesive 51 may be filled in between to firmly fix the adhesive 51. With such a structure, the reliability can be further improved.

FIG. 6A is a schematic plan view showing the resin-molded piezoelectric component 40, and FIG. 6B is a schematic front view showing a resin-molded lead type device. is there. Reference numeral 62 in FIG. 6B indicates a lead connected to a predetermined portion of the external electrode 13. As shown in FIG. 6, the piezoelectric component 40 is made of resin 6 such as wholly aromatic polyester, polyetheretherketone, or polyethersulfone.
If the resin is molded with No. 1, the moisture resistance can be improved. Since the lead 62 is reinforced by bending to have a cross-sectional shape of, for example, a substantially "V" shape, sufficient strength can be obtained even when a thin metal plate material is used.

FIG. 7A is a schematic perspective view showing a state before coating with the heat-shrinkable resin 63, and FIG. 7B is a schematic perspective view showing a state after coating with the heat-shrinkable resin 63. 63a in the figure
Indicates a heat-shrinkable resin after heat-shrinking. As described above, the heat shrinkable resin 63 may cover the entire circumference of the piezoelectric component 40. Even in this case, if the adhesive is used in combination, the metal electrode terminal 41 can be fixed more securely. Since the adhesive for the heat-shrinkable resin 63 does not come into direct contact with the solder at the time of soldering, there is no particular problem if a material having excellent heat resistance such as an epoxy adhesive is used.

The long side length L ₃ (FIG. 6) of the metal electrode terminal 41 is one side of the piezoelectric component 40 when the piezoelectric component 40 is of the surface mount type (FIGS. 4C and 5). It is considered that the length is good, but in the case of the lead type, it is better to further extend the length of the lead terminal 62. FIG.
(A) shows a lead-type piezoelectric component 40 having leads drawn out at opposite positions of the case 14 on a mother board 22.
FIG. 3B is a schematic perspective view showing a state in which it is mounted on
Is a schematic plan view showing a surface mount type piezoelectric component 40, and (c) is a schematic plan view showing a lead type piezoelectric component 40 in which leads are drawn out in parallel. As described with reference to FIG. 6, the strength of the lead 62 can be increased when the lead 62 is bent so that the lead 62 has a substantially V-shaped cross-section. Piezoelectric components in which the spreading vibration mode is used are often used in the frequency band of several hundreds KHz to several MHz, and such piezoelectric components are not necessarily surface-mounted such as chip components without leads 62, but lead 62 In many cases, the mounting method of passing through the hole of the circuit board and soldering on the back side of the circuit board is preferred. Corresponding to such parts with leads 62, metal electrode terminal 4
Only a small change to 1 is a great advantage. Although the lead-out directions of the leads 62 are generally parallel (FIG. 8 (c)), the metal electrode terminals 41 can be attached in an arbitrary positional relationship facing the piezoelectric component 40 depending on the purpose (FIG. 8). (A)).

In supplying the leads 62, as shown in FIG. 9, the metallic electrode terminals 41 to which the leads 62 are connected are not supplied as individual components but are supplied in a reel shape having the leads 62 and assembled. Finally, if the method of cutting into the shape shown in FIG.

As described above, according to the third embodiment, it is possible to reduce the price, reduce the number of manufacturing steps, improve the reliability, and flexibly deal with the component mounting method.

<Fourth Preferred Embodiment> FIGS. 10A and 10B are diagrams showing a piezoelectric component according to a fourth preferred embodiment. FIG. 10A is a schematic vertical sectional view, FIG. 10B is a schematic exploded perspective view, and FIG. Is the first (second)
FIG. 5 is a schematic plan view, a back view and a side view of the front and back of the cover body of FIG.

An electrode 83 is formed on a part of the case 14 including the central portion of both outer main surfaces 14b and excluding the portion where the external electrode 13 is present, and is present between the electrode 83 and the internal electrode 12 and between them. A capacitor is formed with a part of the case 14. Other configurations are the same as those of the second embodiment shown in FIG.
It is substantially the same as the piezoelectric component 20 according to.

In the piezoelectric component 50 thus constructed, the first cover body 14A or the second cover body 1 is used.
The desired capacity can be obtained at 4B.

Generally, in the piezoelectric component to which the spreading vibration mode is applied, the size and material of the piezoelectric resonator itself are different depending on the frequency, so that the electrical characteristics of the piezoelectric resonator are different, and the external capacitance value depending on the piezoelectric resonator is several. It is necessary to prepare various types in the range of ten to several hundred pF, and in some cases, several thousand and several hundred pF. For this, the area of the electrode 83, the thickness of each cover body 14A, 14B, or the cover body 14A, 14B
This can be flexibly handled by changing the relative permittivity of the dielectric material used for forming B.

In the fourth embodiment, the frame-shaped spacer 1
Although the case where the external electrode 16 is formed on 4C is shown,
The present invention is not limited to this, and in another embodiment, the same effect can be obtained even if the external electrode 16 is not formed.

According to the piezoelectric component 50, a piezoelectric component of a built-in capacitance type can be realized in a small size, has excellent impact resistance, can be surface-mounted, and can be manufactured at a low cost. Effective as a piezoelectric component.

<Fifth Embodiment> FIG. 11 is a schematic longitudinal sectional view showing a piezoelectric component according to a fifth embodiment.

An electrode 83 is formed on a part of the case 14 including the central part of both outer main surfaces 14b and excluding the external electrode 13 and the part where the metal electrode terminal 41 is present. A capacitor is formed by the electrode 12 and a part of the case 14 existing therebetween. Other configurations are substantially the same as those of the piezoelectric component 40 according to the third embodiment shown in FIG.

Also in the above-mentioned piezoelectric component 60, the piezoelectric component 50 according to the fourth embodiment is matched with the effect of the piezoelectric component 40.
The same effect can be obtained.

[0093]

【Example】

Example 1 The piezoelectric component 10 shown in FIG. 1 was manufactured under the following conditions. First and second cover bodies 14A (14B): vertical x horizontal x thickness = 7 mm x 7 mm x 0.5 mm alumina flat plate Spacer 14C: external shape is vertical x horizontal x thickness = 7 mm x 7 mm
× 0.8mm alumina plate, 5mm × 5mm inside
Piezoelectric resonator 11 having voids of × 0.8 mm: length × width × thickness = 4.65 mm × 4.6
5 mm × 0.4 mm Material for forming piezoelectric substrate 11 a: lead zirconate titanate-based piezoelectric resonator 11 manufacturing method: electrode 11 on piezoelectric substrate 11 a
After printing plate b, it was polarized in an oil bath and cut into a square plate of a predetermined size. Material of electrode 11b, internal electrode 12, external electrode 13: high temperature baking type silver paste containing glass frit Conductive adhesive 15: Adhesive made of urethane resin containing silver as a conductive material, approximately circular with a diameter of 1.5 mm, and thickness of about 300
μm The dimensions of the completed piezoelectric component 10 are 7 × 7 × 1.8 mm
And the dimensions of a general conventional piezoelectric component are 7 × 8.5 × 3.
Compared to 5 mm, it has achieved a small size and low profile,
Moreover, it was possible to realize surface mounting. Even in the drop test from 1 m, displacement of the piezoelectric resonator did not occur, and stable characteristics were obtained.

Example 2 The piezoelectric component 20 shown in FIG. 2 was manufactured under the following conditions.

External electrode 16: High temperature baking type silver paste containing glass frit Other conditions are the same as in the case of Example 1.

Example 3 The piezoelectric component 40 shown in FIG. 4 was manufactured under the following conditions. Metallic electrode terminal 41: thickness 150 μm, phosphor bronze silver plated material Conductive adhesive 15: adhesive containing silver as a conductive material in vinyl resin, approximately circular with a diameter of 2.0 mm, thickness about 300 μ
m Other conditions are the same as in the first embodiment.

Example 4 Piezoelectric component 50 shown in FIG.
Was manufactured under the following conditions. Electrode 83: High temperature baking type silver paste containing glass frit Internal electrode 12: length × width = 4 mm × 4 mm Other conditions are the same as in Example 1.

As a result, one cover body 14A (14
It was possible to form a capacitance of about 330 (pF) in B).

[Brief description of drawings]

FIG. 1 is a diagram showing a piezoelectric component according to a first embodiment of the present invention, in which (a) is a schematic vertical sectional view, (b) is a schematic exploded perspective view, and (c) is a cover body and a spacer. FIG. 3 is a schematic partial plan view and side view of FIG.

FIG. 2A is a schematic vertical sectional view showing a piezoelectric component according to a second embodiment, and FIG. 2B is a schematic vertical sectional view showing a state where the piezoelectric component is mounted on a motherboard or the like. is there.

FIG. 3A is an enlarged perspective view of an essential part showing a case where external electrodes are formed on a pair of side surfaces of a piezoelectric component,
(B) is an enlarged perspective view of a main part showing a structure in which an external electrode is separately formed on a surface orthogonal to the external electrode, and more reliable conduction is achieved.

4A and 4B are diagrams showing a piezoelectric component according to a third embodiment, in which FIG. 4A is a schematic vertical sectional view, FIG. 4B is an enlarged sectional view of a main part, and FIG. It is a schematic longitudinal cross-sectional view.

FIG. 5 is a schematic vertical cross-sectional view showing a state in which an adhesive is filled between the case and the metal electrode terminals to firmly fix the same.

FIG. 6A is a schematic plan view showing a resin-molded piezoelectric component, and FIG. 6B is a schematic side view of a lead type.

7A is a schematic perspective view showing a state before coating with a heat-shrinkable resin, and FIG. 7B is a schematic perspective view showing a state after coating with a heat-shrinkable resin.

FIG. 8A is a schematic perspective view showing a state in which a lead-type piezoelectric component with leads drawn out to opposite surfaces is mounted on a motherboard or the like, and FIG. 8B is a surface-mounting type piezoelectric component. FIG. 1C is a schematic plan view showing a lead-type piezoelectric component in which leads are drawn out in parallel.

FIG. 9 is a schematic plan view for explaining a system for supplying terminals having leads in a reel shape.

10A and 10B are diagrams showing a piezoelectric component according to a fourth embodiment, wherein FIG. 10A is a schematic vertical sectional view, FIG. 10B is a schematic exploded perspective view, and FIG. 10C is a first (second) sectional view. A schematic plan view of the cover body,
It is a rear view and its side view.

FIG. 11 is a schematic vertical sectional view showing a piezoelectric component according to a fifth embodiment.

FIG. 12 is an equivalent circuit diagram of a resonator.

FIG. 13 is a positive feedback Colpitts oscillator circuit diagram.

FIG. 14 is a circuit diagram in the case of using an inverter in a Colpitts type oscillation circuit using a ceramic oscillator.

FIG. 15 is a circuit diagram when an inverter is used in a Colpitts oscillator circuit that uses a ceramic oscillator.

FIG. 16 is a circuit diagram showing a method of use in an actual oscillation circuit.

17A is a schematic perspective view showing a piezoelectric component using a thickness shear vibration mode, FIG. 17B is an exploded perspective view thereof, and FIG. 17C is a piezoelectric resonator mounting portion. Each of the schematic partially exploded perspective views is shown.

FIG. 18 is an equivalent circuit diagram of a piezoelectric component using the thickness shear vibration mode.

FIG. 19A is a schematic perspective view showing a piezoelectric component using an energy trap type thickness longitudinal vibration mode,
(B) is an exploded perspective view thereof.

FIG. 20 is a schematic exploded perspective view showing a piezoelectric component using a spreading vibration mode.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 piezoelectric component 11 piezoelectric resonator 11a piezoelectric substrate 11b electrode 12 internal electrode 13 external electrode 14 case 14a inner main surface 14b outer main surface 15 conductive adhesive

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[Procedure amendment]

[Submission date] January 9, 1996

[Procedure Amendment 1]

[Document name to be amended] Drawing

[Name of item to be corrected] Figure 7

[Correction method] Change

[Correction contents]

FIG. 7

Claims (6)

[Claims] 1. A piezoelectric resonator having electrodes provided on both surfaces of a piezoelectric substrate, and a case for accommodating the piezoelectric resonator, wherein an internal electrode is provided in a part including a central portion of both inner main surfaces of the case. On the other hand, an external electrode is formed on the outer surface of the case, the internal electrode and the external electrode are electrically connected, and the piezoelectric resonator and the internal electrode are substantially the same as the piezoelectric resonator. A piezoelectric component, characterized in that it is connected by a conductive adhesive in the central portion. 2. The piezoelectric resonance of the first cover body and the second cover body, wherein the case includes a flat plate-shaped first cover body, a second cover body and a frame-shaped spacer. The internal electrode is formed in a part including a central portion of a connection surface with the child, and a part of a side surface of the first cover body and the second cover body or a part of the side surface and the connection surface. The piezoelectric component according to claim 1, wherein the external electrode is formed on a part of a surface to be formed. 3. An external device for electrically connecting the external electrode formed on the first cover body and the external electrode formed on the second cover body to a part of an outer surface of the spacer. The piezoelectric component according to claim 2, wherein electrodes are formed. 4. The metal electrode terminal is provided outside the case, according to claim 1 or 2.
The piezoelectric component described. 5. Including a central portion of both outer main surfaces of the case,
An electrode is formed in a part except a part where the external electrode is present, and a capacitor is formed by the electrode, the internal electrode and a part of the case existing between them. The piezoelectric component according to any one of items 1 to 3. 6. Including a central portion of both outer main surfaces of the case,
Further, an electrode is formed on a part excluding the external electrode and a part where the metal electrode terminal is present, and a capacitor is formed by the electrode, the internal electrode and a part of the case existing therebetween. The piezoelectric component according to claim 4, wherein