KR100280072B1 - Piezoelectric resonator and electronic component including same - Google Patents

Abstract

The present invention provides a piezoelectric resonator having a small spurious resonance, a large frequency difference ΔF between the resonant frequency and the anti-resonant frequency, easy to miniaturize, and preventing breakage and damage of an external electrode, and a novel piezoelectric resonator. Provide electronic components. The piezoelectric resonator includes a rectangular parallelepiped base member. The base member includes a plurality of laminated piezoelectric layers. The middle portions of the piezoelectric layers are polarized in opposite directions with respect to each other. On the main surface of the middle portion of the piezoelectric layer, first and second groups of internal electrodes are alternately formed from both sides of the base member. On both sides of the base member, first and second external electrodes are arranged to be alternately connected to the first and second groups of internal electrodes.

Description

Piezoelectric resonator and electronic component including same {Piezoelectric resonator and electronic component including same}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric resonator and an electronic component having such a piezoelectric resonator. More particularly, the present invention relates to an electronic component including a piezoelectric resonator and a piezoelectric resonator such as an oscillator, a discriminator, a filter, and the like which make the most of the mechanical resonance of the piezoelectric body. It is about.

37 is a perspective view of a conventional piezoelectric resonator. The piezoelectric resonator 1 includes a piezoelectric substrate 2 that is, for example, a rectangular plate when viewed from above. The piezoelectric substrate 2 is polarized in the thickness direction. Electrodes 3 are formed on both main surfaces of the piezoelectric substrate 2. When a signal is input between these electrodes 3, an electric field is applied to the piezoelectric substrate 2 in the thickness direction, and the piezoelectric substrate 2 vibrates in the longitudinal direction.

38 shows a piezoelectric resonator 1 in which electrodes 3 are disposed on both main surfaces of the piezoelectric substrate 2 in a square plate shape when viewed from above. The piezoelectric substrate 2 of the piezoelectric resonator 1 is polarized in the thickness direction. When a signal is input between the electrodes 3 of the piezoelectric resonator 1, an electric field is applied to the piezoelectric substrate 2 in the thickness direction, and the piezoelectric substrate 2 vibrates in a square vibration mode.

These piezoelectric resonators are unstiffened type resonators whose application direction and polarization direction of the electric field are different from the vibration direction. The electromechanical coefficient of the non-rigid piezoelectric resonator is lower than that of the rigid piezoelectric resonator in which the electric field application direction and polarization direction coincide with the vibration direction. The non-rigid piezoelectric resonator has a relatively small frequency difference ΔF between the resonance frequency and the anti-resonant frequency. This causes a problem that the frequency bandwidth being used is narrow when the non-rigid piezoelectric resonator is used as the oscillator or the filter. Therefore, in the non-rigid piezoelectric resonator and the electronic component provided with such a piezoelectric resonator, the degree of freedom in design of the characteristics becomes low.

The piezoelectric resonator shown in FIG. 37 generates primary mode resonance in the longitudinal mode. In addition, due to the structure of the piezoelectric resonator, the piezoelectric resonator generates spurious resonance in a large spurious resonance and in a width mode in a harmonic mode such as tertiary mode and fifth order mode. In order to suppress such spurious resonance, it is considered to take some corrective measures such as polishing the resonator surface, increasing the mass, and changing the shape of the electrode to the piezoelectric resonator. However, these corrective measures have a problem of causing rise in production price and waste of time and effort.

Since the piezoelectric substrate of the piezoelectric resonator shown in Fig. 37 has a rectangular plate shape and must have the required strength, the substrate cannot be made of a thin film substrate, and this substrate has a minimum thickness. Therefore, the distance between electrodes cannot be reduced, and the capacity between terminals cannot be increased. In addition, due to the disadvantages and limitations in the design and production of piezoelectric resonators, it is extremely difficult to achieve impedance matching with an external circuit.

In order to form a ladder filter in which a plurality of piezoelectric resonators are alternately connected in series and in parallel, the capacitance ratio of the series resonator to the parallel resonator increases, so that the amount of attenuation must be increased in a region other than the bandpass. However, the piezoelectric resonator may not obtain a large amount of attenuation because of the limitations described above in shape and configuration.

The piezoelectric resonator shown in FIG. 38 generates the first resonance in the square mode. Due to this structure of the piezoelectric resonator, a large spurious resonance such as resonance of the thickness mode, resonance of the third harmonic, etc. will occur largely in the planar direction. In addition, since the piezoelectric resonator is required to be enlarged in order to obtain the same resonant frequency as compared with the piezoelectric resonator using longitudinal vibration, the piezoelectric resonator of the kind shown in FIG. 38 is difficult to miniaturize.

In the case of forming a ladder filter using a plurality of piezoelectric resonators, in order to increase the capacity ratio between the series resonators and the parallel resonators, the thickness of the resonators connected in series is thickened, and electrodes are formed only on a part of the piezoelectric substrate. The method of making small capacity is used. However, since electrodes are formed only partially on the surface of the piezoelectric substrate, the frequency difference ΔF between the capacitance and the resonance frequency and the anti-resonant frequency is reduced. Therefore, even in the resonators connected in parallel, the frequency difference ΔF needs to be reduced. As a result, the piezoelectricity of the piezoelectric substrate is not effectively used, and the transmission bandwidth of the filter is not increased.

A piezoelectric resonator with a small spurious resonance and a large frequency difference ΔF between the resonance frequency and the anti-resonance frequency is considered in Japanese Patent Application No. 8-110475. 39 shows a piezoelectric resonator having such a structure. In the piezoelectric resonator 4 illustrated in FIG. 39, a plurality of piezoelectric layers 6 and a plurality of electrodes 7 are alternately stacked to form a narrow base member 5, and the plurality of piezoelectric layers 6 are polarized in the longitudinal direction of the base member. The piezoelectric resonator 4 of this laminated structure is a rigid piezoelectric resonator in which the piezoelectric layer 6 is arranged so that the polarization direction of the piezoelectric layer 6 and the application direction of the electric field coincide with the vibration direction. Therefore, compared with non-rigid piezoelectric resonators whose vibration direction is different from the polarization direction and the electric field direction, the rigid piezoelectric resonator has a large electromechanical coupling coefficient and a large frequency difference ΔF between the resonant frequency and the anti-resonant frequency. In addition, in the piezoelectric resonator 4 having the above-described laminated structure shown in FIG. 39, there is a low possibility that vibrations different from the basic vibrations occur in modes such as the width mode and the thickness mode.

In the piezoelectric resonator 4 having such a laminated structure, the ends of the electrode 7 are exposed on all side surfaces of the base member 5. Therefore, on the first side surface of the base member 5, the ends of the first alternate electrodes 7 are covered with the insulating resin film 8a, and the external electrode 9a is formed to be connected to the other alternate electrodes 7. Further, on the second side opposite to the first side of the base member 5, the ends of the second alternate electrodes 7 are covered with the insulating resin film 8b, and the external electrode 9b is covered with the first insulating electrode 8a. It is arranged to connect to these seven. In the piezoelectric resonator 4 having the laminated structure, the capacitance C between the external electrodes 9a and 9b is expressed by the relational formula C ∝ nS / T. Here, S represents the area of the cross section orthogonal to the longitudinal direction of the base member 5, or the area of the main surface of the piezoelectric layer 6, T represents the thickness of the piezoelectric layer 6, or the spacing between the electrodes 7, n is the electrodes The number of floors in 7 is shown. Therefore, in the piezoelectric resonator 4 having this laminated structure, even if the size of the resonator is reduced by reducing the area S, it is necessary to reduce T or increase n to obtain the same capacitance C. In addition, in a small piezoelectric resonator having an interval between electrodes 7, for example, 100 μm or less, it is difficult to accurately form the insulating resin films 8a and 8b at a desired position by printing or the like. It is difficult to substantially reduce the size of the configuration.

In the piezoelectric resonator 4 having such a laminated structure, since the external electrodes 9a and 9b formed on the insulating resin films 8a and 8b have different thermal expansion coefficients from the insulating resin films 8a and 8b, the external electrodes 9a and 9b may be broken or damaged by damage. It is possible that the external electrodes 9a and 9b are partially or completely divided from the insulating resin films 8a and 8b as shown in FIG. 39 by heat shock or thermal cycling during the continuous process.

In order to solve the above-mentioned problems, preferred embodiments of the present invention, the spurious resonance is small, the frequency difference ΔF between the resonant frequency and the anti-resonant frequency is large, miniaturization is easy, and the breakage and damage of the external electrode is prevented It provides a piezoelectric resonator. In addition, preferred embodiments of the present invention provide an electronic component having a piezoelectric resonator of this novel structure.

1 is a perspective view of a piezoelectric resonator according to a preferred embodiment of the present invention.

FIG. 2 is a diagram illustrating a structure of the piezoelectric resonator illustrated in FIG. 1.

3A is a plan view of an internal electrode used in the piezoelectric resonators shown in FIGS. 1 and 2.

3B is a plan view of an internal electrode used in the piezoelectric resonators shown in FIGS. 1 and 2.

FIG. 3C is a diagram illustrating a central axis and a center line of the base member used in the piezoelectric resonators shown in FIGS. 1 and 2, and center axes and center lines of opposing parts in the electrodes.

4 is a perspective view of an unstiffened piezoelectric resonator resonating in the longitudinal direction as a comparative example.

5 is a perspective view of a stiffened piezoelectric resonator resonating in the longitudinal direction.

6 is a perspective view of a non-rigid piezoelectric resonator vibrating in a square vibration mode as a comparative example.

FIG. 7A is a plan view showing a variation of an electrode used in the piezoelectric resonators shown in FIGS. 1 and 2.

FIG. 7B is a plan view showing a variation of an electrode used in the piezoelectric resonators shown in FIGS. 1 and 2.

8A is a plan view showing another modification of an electrode used in the piezoelectric resonators shown in FIGS. 1 and 2.

FIG. 8B is a plan view showing another variation of an electrode used in the piezoelectric resonators shown in FIGS. 1 and 2.

9 is a perspective view of another piezoelectric resonator in accordance with another preferred embodiment of the present invention.

10A is a plan view of an electrode used in the piezoelectric resonator shown in FIG. 9.

FIG. 10B is a plan view of an electrode used in the piezoelectric resonator shown in FIG. 9.

FIG. 11 is a view showing main parts of a mother substrate used in the manufacture of the piezoelectric resonator shown in FIG.

FIG. 12 is a view showing main portions of an external electrode used in manufacturing the piezoelectric resonator shown in FIG. 9.

FIG. 13A is a plan view illustrating one modification of an electrode used in the piezoelectric resonator illustrated in FIG. 9.

FIG. 13B is a plan view illustrating one modification of an electrode used in the piezoelectric resonator illustrated in FIG. 9.

FIG. 13C shows opposing portions of the first and second electrodes in the piezoelectric resonators using the central axis and center point of the base member used in the piezoelectric resonator shown in FIG. 9 and the first and second electrodes shown in FIG. A diagram showing the central axis and center line of a.

13D and 13E are plan views illustrating other modifications of the first and second groups of internal electrodes used in the piezoelectric resonator shown in FIG. 9.

14A and 14B are plan views showing deformations of electrodes used in the piezoelectric resonators shown in FIGS. 1, 2, and 9.

15A, 15B, 15C, 15D, 15E, 15F, 15G, and 15H are plan views showing other variations of electrodes used in the piezoelectric resonators shown in FIGS. 1, 2, and 9.

16 illustrates another piezoelectric resonator according to a preferred embodiment of the present invention.

17A and 17B illustrate electrodes used in the piezoelectric resonator illustrated in FIG. 16.

18A and 18B show another variation of the electrodes used in the piezoelectric resonator shown in FIG. 9.

19 shows another piezoelectric resonator according to a preferred embodiment of the present invention.

20A and 20B are plan views of electrodes used in the piezoelectric resonator shown in FIG. 19.

21A and 21B are plan views illustrating other modifications of internal electrodes used in the piezoelectric resonator illustrated in FIG. 19.

22A, 22B, 22C, 22D, 22E, 22F, 22G, 22H, 22I, 22J, 22K, 22L, 22M and 22N are piezoelectric resonators shown in FIG. 19. Is a plan view showing another variation of the electrodes used in the process.

23 is a perspective view of an electronic component using a piezoelectric resonator according to a preferred embodiment of the present invention.

FIG. 24 is a perspective view of an insulator substrate used in the electronic component shown in FIG. 23.

FIG. 25 is an exploded perspective view of the electronic component illustrated in FIG. 23.

Fig. 26 is a diagram showing another structure for mounting a piezoelectric resonator on an insulator substrate.

FIG. 27 is a side view of the structure shown in FIG. 26 mounting a piezoelectric resonator. FIG.

28 is a view showing another structure in which the piezoelectric resonator is mounted on the insulator substrate.

Fig. 29 is a side view of the structure shown in Fig. 28 for mounting the piezoelectric resonator.

30 is a view showing another electronic component using a piezoelectric resonator according to a preferred embodiment of the present invention.

FIG. 31 is a side view of the structure shown in FIG. 30 mounting a piezoelectric resonator. FIG.

32 is a plan view showing the main part of a ladder filter using a piezoelectric resonator according to a preferred embodiment of the present invention.

33 is an exploded perspective view of a main part of the ladder filter shown in FIG. 32.

34 is an equivalent circuit diagram of the ladder filter shown in FIGS. 32 and 33.

35 is a plan view showing the main part of another ladder filter using a piezoelectric resonator according to a preferred embodiment of the present invention.

36 is an exploded perspective view of a main part of the ladder filter shown in FIG. 35.

37 is a perspective view of a conventional piezoelectric resonator.

38 is a perspective view of another conventional piezoelectric resonator.

39 shows a piezoelectric resonator provided as a background of the present invention and having a laminated structure.

FIG. 40 is a view showing a state where a conductive resin layer is disposed on a surface of an external electrode of the piezoelectric resonator shown in FIG. 39.

<Description of Major Symbols in Drawing>

10 ... piezoelectric resonators 12 ... base member

14 ... piezoelectric layer 16, 18 ... internal electrode

20, 22 ... First and second external electrodes 60 ... Electronic components

62 ... insulator substrate 64 ... recess

66, 68 ... pattern electrode 70 ... projection

72 ... conductive wire 74 ... metal cap

90, 92, 94, 96 ... pattern electrode

98, 100, 102, 104, 106, 108, 110, 112 ... protrusion

A piezoelectric resonator according to a preferred embodiment of the present invention, the base member having a length; A plurality of internal electrodes having a substantially planar shape disposed substantially perpendicular to the length of the base member at intervals along the length of the base member; And a first external electrode and a second external electrode formed on the surface of the base member and connected to the plurality of internal electrodes. The base member includes a plurality of laminated piezoelectric layers; The plurality of piezoelectric layers are polarized along the length of the base member; The plurality of internal electrodes are disposed on surfaces of the plurality of piezoelectric layers substantially orthogonal to the longitudinal direction of the base member; The first group of the plurality of internal electrodes is connected to the first external electrode and arranged so as not to be exposed at the portion where the second external electrode is disposed on the surface of the base member; The second group of the plurality of internal electrodes is connected to the second external electrode, and is arranged so as not to be exposed in the portion where the first external electrode is disposed on the surface of the base member.

In the piezoelectric resonator according to the preferred embodiment of the present invention, the central axis or the center point of the shape formed by stacking adjacent internal electrodes, preferably, the center axis or the center point of the base member on a plane substantially perpendicular to the length of the base member. Matches.

The first and second external electrodes, each of which may be disposed on the other side of the base member. Further, the first and second external electrodes may each be disposed on one common side of the base member.

The piezoelectric resonator preferably vibrates in the longitudinal vibration mode. The first and second external electrodes, each of which may be connected to the first and second groups of internal electrodes, may be connected at one side of the base member near one end and the other end when viewed from the center in the width direction of the base member. It may be arranged extending along the length of the base member.

Grooves may be formed along the longitudinal direction of the base member at a substantially central portion in the width direction from the side where the first and second external electrodes of the base member are disposed, and the first and second external electrodes may have one common side and the base member. It may be arranged on the other side divided by the groove of the side of the.

Each of the first and second groups of internal electrodes includes a plurality of internal electrodes.

The piezoelectric resonator according to a preferred embodiment of the present invention may further include a mounting member formed in a substantially central portion of the base member in the longitudinal direction.

The piezoelectric resonator may further include a mounting member disposed between the central portion of the base member and the support member in the longitudinal direction of the support member and the base member.

Preferred embodiments of the present invention also provide an electronic component comprising the piezoelectric resonator of the novel structure described above. The support member includes an insulator substrate on which a pattern electrode is formed; A base member is mounted on the insulator substrate by the mounting member; A cap is disposed on the insulator substrate to cover the base member. The plurality of base members may be mounted on the insulator substrate by the mounting member to form a ladder filter.

A piezoelectric resonator according to a preferred embodiment of the present invention is a rigid piezoelectric resonator, and has a piezoelectric layer in which the polarization direction and the direction in which the electric field is applied coincide with the vibration direction. Therefore, the rigid piezoelectric resonator has a large electromechanical coupling coefficient and a large frequency difference ΔF between the resonance frequency and the empty resonant frequency as compared with the non-rigid piezoelectric resonator whose vibration direction is different from the polarization direction and the application direction of the electric field. In addition, in the rigid piezoelectric resonator, vibration is unlikely to occur in a mode such as a width mode and a thickness mode different from the longitudinal mode.

In the piezoelectric resonator according to the preferred embodiments of the present invention, the electrodes connected to the first external electrode pair are arranged not exposed to the portion where the second external electrode pair is disposed on the surface of the base member, Since the connected electrodes are arranged so as not to be exposed to the portion where the first external electrode is disposed on the surface of the base member, there is no need to form an insulating resin film so that the distal ends of the electrodes are insulated on the surface of the base member. Therefore, the spacing between the electrodes is significantly reduced, so that the miniaturization of the resonator is easy.

In a piezoelectric resonator according to a preferred embodiment of the present invention, between electrodes electrically connected to a first external electrode and a second external electrode, or between electrodes electrically connected to a second external electrode and a first external electrode. Since no insulating resin film is formed therebetween, the external electrodes will not be broken or damaged by thermal shock and thermal cycling.

When manufacturing an electronic component such as an oscillator, a discriminator, a filter, and the like, using a piezoelectric resonator according to a preferred embodiment of the present invention, a piezoelectric resonator is mounted on an insulator substrate on which a pattern electrode is formed. Coated to form a chip-shaped electronic component.

The above and other objects, features, and advantages of the present invention will be described in more detail with reference to the accompanying drawings, in which embodiments are shown. Like reference numerals designate like elements. The description thereof is omitted.

1 is a perspective view showing an example of a piezoelectric resonator according to a preferred embodiment of the present invention. 2 shows the internal structure of a piezoelectric resonator. The piezoelectric resonator 10 shown in FIGS. 1 and 2 preferably comprises a rectangular parallelepiped base member 12 whose dimensions are, for example, about 3.8 mm × about 1 mm × about 1 mm. The base member 12 includes a piezoelectric layer 14 in which a plurality of, for example, twelve layers made of a piezoelectric ceramic material or other suitable material is laminated. The plurality of piezoelectric layers 14 are preferably configured with the same dimensions. A plurality of, for example, eight intermediate piezoelectric layers 14 are polarized in the longitudinal direction of the base member 12 so that adjacent piezoelectric layers 14 are polarized in opposite directions as indicated by the arrows in FIG.

In the plurality of polarized intermediate piezoelectric layers 14, first groups of the internal electrodes 16 and second groups of the internal electrodes 18 are alternately formed on the main surface substantially perpendicular to the length of the base member 12. Therefore, the internal electrodes 16 and 18 are substantially orthogonal to the length of the base member 12, and are disposed along the length of the base member 12 at predetermined intervals. As shown in FIG. 3A, the first group of the internal electrodes 16 is formed on the main surface of the piezoelectric layer 14 except for a vertical strip portion on one side. As shown in FIG. 3B, the second group of the internal electrodes 18 is formed on the main surface of the piezoelectric layer 14 except for the vertical strip portion on the other side. Therefore, the first group of the internal electrodes 16 is formed to be exposed at three sides including the first side of the base member 12 and not to be exposed at the side opposite to the first side. In addition, the second group of the internal electrodes 18 is formed so as not to be exposed at the first side and at three side surfaces including the side opposite to the first side of the base member 12.

The first and second external electrodes 20 and 22 are formed on the first side and the other opposite side of the base member 12, respectively. Therefore, the external electrode 20 is connected to the internal electrode 16 and the external electrode 22 is connected to the internal electrode 18.

In this piezoelectric resonator 10, the first and second external electrodes 20 and 22 are used as input / output electrodes. By adding a signal to the external electrodes 20 and 22, an electric field is applied between the adjacent internal electrodes 16 and 18, so that a plurality of base layers 12 are provided on both ends of the resonator except for a predetermined number of four piezoelectric layers 14, for example. Medium piezoelectric layers 14 are piezoelectrically active. In this case, since the voltage is applied in the reverse direction to the piezoelectric layer 14 polarized in the opposite direction from the base member 12, the piezoelectric layer 14 is stretched and contracted in a single body in the same direction as a whole. In other words, by the use of the first and second groups of the internal electrodes 16 and 18 connected to the first and second external electrodes 20 and 22, a direct current electric field is applied to each piezoelectric layer 14 in the longitudinal direction of the base member 12, Driving force for expansion and contraction is generated in each piezoelectric layer 14. Therefore, the basic vibration is applied to the piezoelectric resonator 10 in the longitudinal vibration mode at the vibration node that does not generate any vibration at approximately the center portion along the longitudinal direction of the base member 12.

In the piezoelectric resonator 10, the polarization direction of the piezoelectric layer 14, the application direction of the electric field generated by the input signal, and the vibration direction in the piezoelectric layer 14 preferably coincide. In other words, the piezoelectric resonator 10 is a rigid piezoelectric resonator. The piezoelectric resonator 10 has a larger electromechanical coupling coefficient than the non-rigid piezoelectric resonator in which the polarization direction and the electric field application direction differ from the vibration direction. Therefore, the piezoelectric resonator 10 has a larger frequency difference ΔF between the resonance frequency and the anti-resonant frequency than the conventional non-rigid piezoelectric resonator. This means that, in the present piezoelectric resonator 10, a wider frequency characteristic can be obtained than the conventional non-rigid piezoelectric resonator.

In order to measure the characteristic difference between the rigid piezoelectric resonator and the non-rigid piezoelectric resonator, the piezoelectric resonators shown in FIGS. 4, 5 and 6 were fabricated. The piezoelectric resonator shown in FIG. 4 was produced by forming electrodes on both surfaces in the thickness direction on a piezoelectric substrate having dimensions of approximately 4.0 mm x 1.0 mm x 0.38 mm. This piezoelectric resonator was polarized in the thickness direction and vibrated in the longitudinal direction when a signal was applied to the electrode.

The piezoelectric resonator shown in FIG. 5 is manufactured with the same dimensions as the piezoelectric resonator shown in FIG. Electrodes were formed on both surfaces in the longitudinal direction of the piezoelectric substrate. This piezoelectric resonator was polarized in the longitudinal direction and vibrated in the longitudinal direction when a signal was applied to the electrode. In addition, the piezoelectric resonator shown in FIG. 6 was produced by forming electrodes on both surfaces in the thickness direction of the piezoelectric substrate having dimensions of approximately 4.7 mm x 4.7 mm x 0.38 mm. This piezoelectric resonator was polarized in the thickness direction and vibrated in the planar direction when a signal was applied to the electrode. The piezoelectric resonators shown in FIGS. 4 and 6 are non-rigid piezoelectric resonators, and the piezoelectric resonators shown in FIG. 5 are rigid piezoelectric resonators.

The resonance frequency Fr and the electromechanical coupling coefficient K of each of these piezoelectric resonators were measured, and the results are shown in Tables 1, 2, and 3. Table 1 shows the measurement results of the piezoelectric resonator shown in FIG. 4, Table 2 shows the measurement results of the piezoelectric resonator shown in FIG. 5, and Table 3 shows the measurement results of the piezoelectric resonator shown in FIG.

Basic longitudinal vibration Vertical third harmonic vibration Width mode vibration Resonant Frequency (MHz) 0.460 1.32 1.95 Electromechanical Coupling Factor (%) 18.9 3.9 25.2

Basic longitudinal vibration Vertical third harmonic vibration Width mode vibration Resonant Frequency (MHz) 0.455 1.44 1.96 Electromechanical Coupling Factor (%) 42.9 12.2 4.0

Basic square-type vibration Square-Type Third Harmonic Vibration Thickness mode vibration Resonant Frequency (MHz) 0.458 1.25 5.65 Electromechanical Coupling Factor (%) 35.0 11.5 23.3

From the above measurement results, it can be seen that the rigid piezoelectric resonator has a larger electromechanical coefficient K than the non-rigid piezoelectric resonator, and thus the frequency difference ΔF between the resonance frequency and the anti-resonant frequency is large. Further, the maximum spurious vibration in the rigid piezoelectric resonator is the third harmonic vibration in the longitudinal direction, and the electromechanical coupling coefficient K is 12.2% during the vibration. During the fundamental and other width mode vibrations, the electromechanical coefficient K is as small as 4.0%. On the contrary, in the non-rigid longitudinal vibration piezoelectric resonator, the electromechanical coefficient K is as large as 25.2% during the width mode vibration. In the non-rigid square-type vibrating piezoelectric resonator, the electromechanical coupling coefficient is large (23.2%) during vibration in the thickness mode. Therefore, it can be seen that the rigid piezoelectric resonator has a lower spurious vibration than the non-rigid piezoelectric resonator.

In the piezoelectric resonators 10 shown in FIGS. 1 and 2, the first group of internal electrodes 16 connected to the first external electrode 20 is the second external as compared with the piezoelectric resonators 4 having the laminated structure shown in FIG. 39. The second member of the internal electrode 18 connected to the second external electrode 22 is not formed on the side surface of the base member 12 on which the electrode 22 is formed. Therefore, it is not necessary to form an insulating resin film for insulating the end portions of the internal electrodes 16 and 18 on the side surface of the base member 12. Therefore, the distance between the internal electrodes 16 and 18 can be significantly reduced, so that the piezoelectric resonator can be miniaturized particularly easily.

In the piezoelectric resonator 10, since the insulating resin film is not formed between the external electrodes 20, 22 and the base member 12, compared with the piezoelectric resonator 4 having the laminated structure shown in Fig. 39, the external electrodes 20, 22 are heated. Shock and thermal cycling will not break or damage.

In the piezoelectric resonator 4 having the laminated structure shown in FIG. 39, the external electrodes 9a and 9b formed on the insulating resin films 8a and 8b do not break, as shown in FIG. It is attempted to form the conductive resin layers 9c and 9d on the surface. However, when the insulating resin films 8a, 8b and the conductive resin layers 9c, 9d are formed on the side surface of the base member 5, a large load mass is generated on the side surface of the base member 5, whereby the mechanical quality factor Qm is lowered and the resonance frequency is reduced. The voltage dependence becomes large. On the contrary, in the piezoelectric resonator 10, since such a load mass generated by the resin layer is not generated on the side of the base member 12, the mechanical quality factor Qm does not decrease and the voltage dependency of the resonance frequency does not increase.

As shown in FIG. 3C, the piezoelectric resonator 10 has a plane in which a central axis L1 or a center point P1 having a shape formed by stacking the internal electrodes 16 and 18 is preferably orthogonal to the longitudinal direction of the base member 12. Since it is formed substantially coincident with the central axis L2 or the center point P2, the driving force generated in the piezoelectric layer 14 is adjustable with respect to the central axis of the base member 12, and the base member 12 is hardly bent. Therefore, the occurrence of spurious resonance due to the bending of the base member 12 is sparse, and the possibility of obtaining unwanted characteristics is low.

In the piezoelectric resonator 10, since the internal electrodes 16 and 18 are partially formed on the main surface of the piezoelectric layer 14, the frequency difference ΔF can be adjusted by adjusting the areas in which the internal electrodes 16 and 18 face each other. Therefore, the design freedom of resonator characteristics is advantageously increased.

In the piezoelectric resonator 10, the size of the piezoelectric layer 14 in the longitudinal direction of the base member 12 is changed by changing the area of the internal electrodes 16 and 18 facing each other, the number of stacked piezoelectric layers 14 and the number of internal electrodes 16 and 18, or the base member 12 in the longitudinal direction. The electrical capacitance can be adjusted. In other words, by increasing the opposing areas of the internal electrodes 16, 18, increasing the number of stacked piezoelectric layers 14 or the number of internal electrodes 16, 18, or reducing the dimensions of the piezoelectric layer 14 in the longitudinal direction of the base member 12, It is possible to increase the electrical capacity of the resonator.

On the contrary, by reducing the opposing areas of the internal electrodes 16, 18, reducing the number of stacked piezoelectric layers 14 or the number of internal electrodes 16, 18, or enlarging the dimensions of the piezoelectric layer 14 in the longitudinal direction of the base member 12, The electrical capacity of the resonator can be reduced. Therefore, the electrical capacitance of the resonator is adjusted by changing the opposing areas of the internal electrodes 16 and 18, the number of stacked piezoelectric layers 14 or the number of internal electrodes 16 and 18, or the dimensions of the piezoelectric layers 14 in the longitudinal direction of the base member 12. do. This means high capacity design freedom. Therefore, when the piezoelectric resonator 10 is mounted on a circuit board, impedance matching with an external circuit becomes easy.

In the piezoelectric resonator 10, the piezoelectric resonator 10 is maintained with a constant width of a portion where the internal electrodes 16 and 18 are not formed on the main surface of the piezoelectric layer 14 in order to maintain the insulation state of the end portions of the internal electrodes 16 and 18. Even when the vertical dimension of is reduced, the ratio of the opposing areas of the internal electrodes 16 and 18 to the area of the main surface of the piezoelectric layer 14 does not change. Therefore, it is possible to fabricate a piezoelectric resonator with a low side without lowering the efficiency of the driving force generated in the piezoelectric layer 14.

The piezoelectric resonator 10 shown in Figs. 1 and 2 has two parts, one of which has an internal electrode 16, one upper side and one vertical side adjacent to the upper side, on the main surface of the piezoelectric layer 14, as shown in Fig. 7A. 7B, the internal electrode 18 is configured to be formed on the main surface of the piezoelectric layer 14 except two portions of the other upper side and the vertical side adjacent to the upper side, as shown in FIG. Can be.

In the piezoelectric resonator 10 illustrated in FIGS. 1 and 2, the internal electrode 16 is formed on the main surface of the piezoelectric layer 14 except for two adjacent side portions, as shown in FIG. 8A, and the internal electrode 18. As shown in Fig. 8B, the main surface of the piezoelectric layer 14 may be formed to be formed at portions other than the side portions of the other two adjacent regions.

9 illustrates another piezoelectric resonator in accordance with a preferred embodiment of the present invention. The piezoelectric resonators shown in FIG. 9 have different configurations of the internal electrodes 16 and 18 and the external electrodes 20 and 22 as compared with the piezoelectric resonators shown in FIGS. 1 and 2.

In detail, in the piezoelectric resonator 10 shown in FIG. 9, the first group of the internal electrodes 16 is located in the main surface of the piezoelectric layer 14 except the middle portion of the upper side from one end portion as shown in FIG. 10A. As shown in Fig. 10B, a second group of the internal electrodes 18 is formed on the main surface of the piezoelectric layer 14 except for the portion from the middle portion on the upper side to the other end portion. In other words, the first group of the internal electrodes 16 is not exposed at the position extending from the middle portion to the one end portion in the width direction on the upper surface of the base member 12, and is formed to be exposed at the other end portion. The second group of internal electrodes 18 is not exposed at the position extending from the middle portion to one end portion in the width direction on the upper side of the base member 12, and is formed to be exposed at the other end portion.

The first and second external electrodes 20 and 22 are arranged in two rows in the longitudinal direction of the base member 12 on one side and the other end of the base member 12 when viewed from the center in the width direction of the base member 12. In this case, the first external electrode 20 is connected to the first group of internal electrodes 16, and the second external electrode 22 is connected to the second group of internal electrodes 18.

The piezoelectric resonator 10 shown in FIG. 9 has another advantage. Compared with the piezoelectric resonators shown in FIGS. 1 and 2, in order to maintain the insulating state of the end portions of the first and second groups of the internal electrodes 16 and 18, the internal electrodes 16 and 18 may be formed on the main surface of the piezoelectric layer 14. Even when the dimensions of the piezoelectric resonator 10 are reduced in the width direction while maintaining the width of the portion where the first and second groups are not formed, the internal electrodes 16 and 18 with respect to the area of the main surface of the piezoelectric layer 14 are formed. Since the ratio of the opposing areas of the first and second groups does not change, it is possible to reduce the size of the piezoelectric resonator in the width direction without lowering the efficiency of the driving force generated in the piezoelectric layer 14.

Next, an example of the manufacturing method of the piezoelectric resonator 10 shown in FIG.

As shown in Fig. 11, a plurality of, for example, 12 piezoelectric ceramic mother substrates 15 are prepared. On each of the main surfaces of the five mother substrates 15, mother electrodes 17 serving as first groups of the plurality of internal electrodes 16 are formed, respectively. On one main surface of the other four mother substrates 15, mother electrodes 19 serving as second groups of the plurality of internal electrodes 18 are formed, respectively. No electrodes are formed on the remaining three motherboard 15. These mother substrates 15 are laminated to form a laminate. This laminate is cut along a one-dot chain line extending in the transverse direction, as shown in FIG.

As shown in FIG. 12, electrodes 21 serving as external electrodes 20 and 22 are formed on the cut surface of the cut laminate. By applying a direct current high voltage to the adjacent electrodes 21, each mother substrate 15 or each piezoelectric layer 14 is polarized. This laminated body is cut | disconnected along the dashed-dotted line shown in FIG. 12, and the piezoelectric resonator 10 is formed. In particular, it is possible to manufacture piezoelectric resonators having an arrangement and configuration other than the piezoelectric resonators shown in FIG. 9 in the same manner.

In the piezoelectric resonator 10 shown in FIG. 9, as shown in FIG. 13A, the internal electrode 16 is a portion of the main surface of the piezoelectric layer 14 except a portion extending from the middle portion of the upper side to one end and the lower side portion. And a second group of the internal electrodes 18 have a reflection image of the internal electrodes 16, and as shown in FIG. 13B, a portion extending from the middle portion of the upper side to the other end and the lower portion in the main surface of the piezoelectric layer 14 It may be configured to be formed on portions except the side portion.

A piezoelectric resonator 10 having a first group of internal electrodes 16 and a second group of internal electrodes 18 shown in FIGS. 10A and 10B is preferably a central axis L1 or a center point P1 having a shape formed by overlapping internal electrodes 16, 18. 13C, since the driving force generated in the piezoelectric layer 14 is formed to substantially coincide with the central axis L2 or the center point P2 of the plane substantially orthogonal to the longitudinal direction of the base member 12, Adjustable about the central axis, base member 12 is hardly bent. Therefore, the piezoelectric resonator has another advantage. The occurrence of spurious resonances due to bending in the base member 12 is sparse, and unwanted characteristics caused by the spurious resonances are not obtained.

In the piezoelectric resonator 10 shown in FIG. 1, as shown in FIG. 13D, the first group of the internal electrodes 16 is not formed on the main surface of the piezoelectric layer 14 on three side portions except for the upper side, The second group of electrodes 18 has a reflection image of the first group of internal electrodes 16, and as shown in Fig. 13E, on the main surface of the piezoelectric layer 14, there are three side portions except the upper side on which the external electrodes are disposed. It may be configured not to be formed. In the case where the first and second groups of the internal electrodes 16 and 18 are formed by the above-described method, since the first and second groups of the internal electrodes 16 and 18 are not exposed at all on the surface of the piezoelectric resonator 10, this piezoelectric The resonator has another advantage. The moisture resistance or the water resistance of the first and second groups of the internal electrodes 16 and 18 is improved, and the insulation resistance between the first and second groups of the internal electrodes 16 and 18 is unlikely to decrease.

The piezoelectric resonator 10 shown in FIG. 1 includes a portion in which the first group of internal electrodes 16 extend from the middle portion of the upper side to one end on the main surface of the piezoelectric layer 14, as shown in FIG. 14A. And a second group of internal electrodes 18, having a reflection image of the first group of internal electrodes 16, formed on portions except the vertical side adjacent to the upper side of the piezoelectric layer 14, as shown in FIG. It can be configured to be formed in a portion extending from the middle portion of the side to the other end and the portion except the vertical side portion adjacent to this portion.

In the piezoelectric resonator 10 shown in FIG. 1, the first group of internal electrodes 16 is, as shown in FIG. 15A, in the main surface of the piezoelectric layer 14, from the middle portion of the upper side to the middle portion of the vertical side adjacent to this portion. And a second group of internal electrodes 18 having a reflection image of the first group of internal electrodes 16, and as shown in FIG. 15B, in the main surface of the piezoelectric layer 14, an intermediate portion of the upper side. It can be configured to be formed in a portion extending from the middle portion of the vertical side adjacent to this portion.

In the piezoelectric resonator 10 illustrated in FIG. 1, the first group of internal electrodes 16 is perpendicular to the three sides from the center, that is, the upper side, the lower side, and one vertical side of the main surface of the piezoelectric layer 14, as shown in FIG. 15C. Formed in a portion extending to each intermediate portion of the side surface, and the second group of the internal electrodes 18 has a reflection image of the first group of the internal electrodes 16, and as shown in FIG. 15D, on the main surface of the piezoelectric layer 14, It may be configured to be formed on three sides, i.e., the upper side, the lower side, and the portion extending from the center to each intermediate portion of the other vertical side.

In the piezoelectric resonator 10 illustrated in FIG. 1, as shown in FIG. 15E, the first group of internal electrodes 16 does not extend from the center to the vertical side portions of both sides of the piezoelectric layer 14 on the main surface of the piezoelectric layer 14. And a second group of internal electrodes 18, having a reflection image of the first group of internal electrodes 16, formed at portions extending to the respective intermediate portions of the lower side and the lower surface of the piezoelectric layer 14, as shown in FIG. 15F. It may be configured to be formed in a portion extending from the center to the vertical side portions of both sides of the piezoelectric layer 14 to each intermediate portion of the upper side and the lower side.

In the piezoelectric resonator 10 shown in FIG. 1, the first group of internal electrodes 16 extends from the center to the vertical sides of both sides of the piezoelectric layer 14, as shown in FIG. 15G. And a second group of internal electrodes 18 has a reflection image of the first group of internal electrodes 16, and as shown in FIG. 15H, on the main surface of the piezoelectric layer 14, the vertical sides of both sides of the piezoelectric layer 14 from the center It may be configured to be formed in the portion extending to.

Insulation of the distal ends of the first and second groups of internal electrodes 16, 18 when the first and second groups of internal electrodes 16, 18 are arranged as shown in FIGS. 13A and 13B or 15G and 15H. In order to maintain the state, the dimensions of the piezoelectric resonator are reduced in the width direction while maintaining the width of the portion where the first group of the internal electrodes 16 or the second group of the internal electrodes 18 are not formed on the main surface of the piezoelectric layer 14. Even if the ratio of the area of the first and second groups of the internal electrodes 16 and 18 to the area of the main surface of the piezoelectric layer 14 does not change, the efficiency of the driving force generated in the piezoelectric layer 14 is not reduced. It is possible to reduce the size of the piezoelectric resonator in the width direction.

When the first and second groups of the internal electrodes 16, 18 are arranged as shown in Figs. 13E, 13F, and 15A-15H, the piezoelectric resonators 10 are formed of the first and second of the internal electrodes 16, 18. Since the center axis or the center point of the shape formed by overlapping the two groups is formed to be substantially coincident with the center axis or the center point of the plane substantially orthogonal to the longitudinal direction of the base member 12, the driving force generated in the piezoelectric layer 14 Adjustable about the central axis of the member 12, the base member 12 is hardly bent. Therefore, the piezoelectric resonator has another advantage. The occurrence of spurious resonances due to bending in the base member 12 is sparse and is unlikely to obtain unwanted characteristics. In these preferred embodiments, the shape of the opposing portions of the first and second groups of the internal electrodes 16, 18 is preferably symmetrical with respect to the main surface of the piezoelectric layer 14.

In each of the piezoelectric resonators 10 described above, the intermediate portion disposed along the longitudinal direction of the base member 12 is piezoelectrically active and vibrates. Thereby, both ends of the base member 12 are piezoelectrically inactive. However, this inactive portion is also piezoelectrically active when the piezoelectric layer is polarized and an electric field is applied, otherwise it is inactive.

16 illustrates another piezoelectric resonator in accordance with a preferred embodiment of the present invention. The piezoelectric resonators shown in FIG. 16 have different shapes of the internal electrodes 16 and 18 as compared with the piezoelectric resonators shown in FIGS. 1 and 2.

In the piezoelectric resonator 10 shown in FIG. 16, the internal electrode 16 is formed in a portion extending from the center to the middle portion of one vertical side on the main surface of the piezoelectric layer 14, as shown in FIG. 17A, and the internal electrode 18. This has a reflection image of the first group of internal electrodes 16, and is formed in a portion extending from the center to the middle portion of the other vertical side on the main surface of the piezoelectric layer 14, as shown in Fig. 17B. Although not shown in FIG. 16, the first external electrode 20 is connected to the first group of the internal electrodes 16, and the second external electrode 22 is connected to the second group of the internal electrodes 18.

In the piezoelectric resonator 10 shown in FIG. 16, since the internal electrodes 16 and 18 are not exposed at all on the surface of the piezoelectric resonator 10, moisture resistance and water resistance of the internal electrodes 16 and 18 are improved, and Insulation resistance is unlikely to drop.

In the piezoelectric resonator 10 shown in FIG. 9, as shown in FIG. 18A, the internal electrode 16 is not formed on three side portions except the upper side of the main surface of the piezoelectric layer 14. The two groups have a reflection image of the first group of the internal electrodes 16, and as shown in Fig. 18B, the main surface of the piezoelectric layer 14 may be formed so as not to be formed on three side portions except the upper side portion. When the internal electrodes 16 and 18 are formed by the above method, the internal electrodes 16 and 18 have improved moisture resistance and water resistance, and the insulation resistance between the internal electrodes 16 and 18 is also the same as that of the piezoelectric resonator 10 shown in FIG. It is unlikely to degrade.

19 illustrates another piezoelectric resonator in accordance with a preferred embodiment of the present invention. The piezoelectric resonator shown in FIG. 19 is different from the piezoelectric resonator described above, in particular, the internal electrodes 16 and 18 and the external electrodes 20 and 22 are different.

In the piezoelectric resonator 10 shown in FIG. 19, the first group of internal electrodes 16 is three sides from the center, i.e., upper side, lower side and one vertical side, on the main surface of the piezoelectric layer 14, as shown in FIG. 20A. And a second group of internal electrodes 18 having a reflection image of the first group of internal electrodes 16, as shown in Fig. 20B, at the main surface of the piezoelectric layer 14, the center of which From the three sides, i.e., the portions extending to the respective intermediate portions of the upper side, the lower side, and the other vertical side.

The first external electrode 20 is formed on one side, the upper side and the lower side of the base member 12 so as to be connected to the first group of the internal electrodes 16. The second external electrode 22 is formed on the other side, upper side and lower side of the base member 12 so as to be connected to the second group of the internal electrodes 18. In this case, the external electrodes 20 and 22 are arranged in a row on the upper side and the lower side of the base member 12.

The piezoelectric resonator 10 shown in FIG. 19 has another advantage. Since the external electrodes 20 and 22 are formed on the other three sides of the base member 12, the piezoelectric resonator may be mounted on a circuit board in an intact shape, rotated 90 degrees, and upside down.

In the piezoelectric resonator 10 shown in FIG. 19, the first group of internal electrodes 16 has a vertical side on both sides of the main surface of the piezoelectric layer 14 as shown in FIG. 22C as compared with the electrode shape shown in FIG. 20A. Not formed in the portion, the second group of the internal electrodes 18 has a reflection image of the first group of the internal electrodes 16, and compared with the electrode shape shown in FIG. 20B, as shown in FIG. 22D, the piezoelectric layer 14 In the main surface of the, it can be configured not to be formed in the vertical side portions on both sides.

In the piezoelectric resonator 10 shown in FIG. 19, the first group of internal electrodes 16 is formed in a portion of the main surface of the piezoelectric layer 14 that extends from the center to the vertical portions on both sides, as shown in FIG. 22E, The second group of internal electrodes 18 has a reflection image of the first group of internal electrodes 16, and is formed in a portion extending from the center to the vertical portions on both sides in the main surface of the piezoelectric layer 14, as shown in Fig. 22F. Can be configured. In this case, the piezoelectric resonator 10 shown in FIG. 19 has another advantage. Even when the shape of the piezoelectric resonator 10 is reduced in the width direction, the ratio of the opposing areas of the internal electrodes 16 and 18 to the area of the main surface of the piezoelectric layer 14 does not change, so the efficiency of the driving force generated in the piezoelectric layer 14 is increased. It is possible to reduce the size of the piezoelectric resonator 10 in the width direction without lowering it.

In the piezoelectric resonator 10 shown in Fig. 19, the internal electrodes 16 and 18 may have the electrode shapes shown in Figs. 22G and 22H, 22I and 22J, 22K and 22L or 22M and 22N.

In the piezoelectric resonator 10 illustrated in FIG. 19, at least one first external electrode 20 connected only to a first group of internal electrodes 16 and at least one second external electrode 22 connected to only a second group of internal electrodes 18 are formed. Need to be.

In each piezoelectric resonator 10 described above, the intermediate portion extending in the longitudinal direction of the base member 12 is piezoelectrically active and vibrates. Both end portions in the longitudinal direction of the base member 12 are preferably piezoelectrically inactive portions. However, this inactive portion also becomes a piezoelectrically active portion when the piezoelectric layer is polarized and an electric field is applied, otherwise it remains a piezoelectrically inactive portion. If the inactive part 24 has such a property, it may have another structure.

Using such a piezoelectric resonator 10, electronic components such as an oscillator and a discriminator can be manufactured. 23 is a perspective view of the electronic component 60. The electronic component 60 includes an insulator substrate 62 serving as a supporting member. Two concave portions 64 are preferably formed in opposing end surfaces of the insulator substrate 62. On one surface of the insulator substrate 62, as shown in FIG. 24, two pattern electrodes 66 and 68 are formed. One pattern electrode 66 is formed between the opposing recesses 64 extending in an L shape from the position near one end face toward the center of the insulator substrate 62. The other pattern electrode 68 extends in a straight line between the opposing recesses 64 from the position in the vicinity of the other end face toward the center of the insulator substrate 62. The pattern electrodes 66 and 68 are arranged so as to form an enclosed shape from the recessed portion 64 of the insulator substrate 62 to the opposing surface.

On the end surface of the pattern electrode 66 disposed in the substantially central portion of the insulator substrate 62, projections 70 serving as mounting members are formed by a conductive adhesive or the like. As shown in Fig. 25, as the above-described piezoelectric resonator 10 is mounted on the projection 70, the substantially center portion of the base member 12 is disposed on the projection 70. The external electrode 22 of the piezoelectric resonator 10 is connected to the projection 70, for example. The protrusion 70 may be previously formed on the piezoelectric resonator 10 side. The other external electrode 20 is connected to the pattern electrode 68 with a conductive wire 72. The conductive wire 72 is connected to the center portion of the external electrode 20 of the piezoelectric resonator 10.

The metal cap 74 is disposed on the insulator substrate 62. In order to prevent the metal cap 74 from being short-circuited at the pattern electrodes 66 and 68, the insulator substrate 62 and the pattern electrodes 66 and 68 are previously coated with an insulator resin. The metal cap 74 is disposed thereon to complete the manufacture of the electronic component 60. In this electronic component 60, the pattern electrodes 66 and 68 formed and arranged on the rear surface from the recessed portion 64 of the insulator substrate 62 are used as input / output terminals for connecting to an external circuit.

In this electronic component 60, the projection 70 is formed, and since the center portion of the piezoelectric resonator 10 is fixed to the projection 70, the distal ends of the piezoelectric resonator 10 are arranged separately from the insulator substrate 62, so that vibration is not disturbed. In addition, since the substantially central portion of the piezoelectric resonator 10 serving as the vibration node is fixed to the projection 70 and connected to the conductive wire 72, the excited longitudinal vibration is not weakened.

Electronic component 60 is preferably mounted on a circuit board together with an IC chip and another electronic component to provide a vibrator or discriminator. Since the electronic component 60 having such a structure is sealed and protected by the metal cap 74, it can be used as a chip-like component that can be mounted by reflow soldering.

When the electronic component 60 is used for the vibrator, the spurious resonance is suppressed to a low level by the novel arrangement and features of the piezoelectric resonator 10 used for the electronic component 60, and the rare resonance generated by the spurious resonance is prevented. In addition, since the capacitance of the piezoelectric resonator 10 can be easily set to a desired value, impedance matching with an external circuit is easy. In particular, when an electronic component is used as an oscillator for a voltage controlled oscillator, since the frequency difference ΔF of the resonator becomes large, it is easy to obtain a wide frequency variable range that has not been obtained conventionally.

When the electronic component 60 is used as the discriminator, a wider peak-division range is obtained because the frequency difference ΔF of the resonator becomes large. In addition, since the capacitance range of the resonator is wide, it is easy to match impedance with an external circuit.

Since the piezoelectric resonator 10 can be mounted on the insulator substrate 62, as shown in FIGS. 26 and 27, two projections 70 made of a conductive material such as a conductive adhesive are formed on both surfaces of the pattern electrodes 66 and 68, and the piezoelectric body is formed. The external electrodes 20 and 22 of the resonator 10 are connected to two projections 70. 28 and 29, the piezoelectric resonator 10 is mounted on the insulator substrate 62 so that two projections 70 made of a conductive material such as a conductive adhesive are formed on the insulator substrate 62, and the conductive wire 72 The external electrodes 20 and 22 of the piezoelectric resonator 10 and the pattern electrodes 66 and 68 are connected by this. The projection 70 may be formed in advance on the piezoelectric resonator 10.

30 shows another electronic component constructed using a piezoelectric resonator in accordance with preferred embodiments of the present invention. Fig. 31 is a side view showing a method of mounting this piezoelectric resonator. The electronic components shown in FIGS. 30 and 31, in particular compared to the electronic components shown in FIGS. 26 and 27, have external electrodes 20, 22 on one side of the base member 12 as shown in FIG. 9, for example. The difference is that the piezoelectric resonator 10 is formed.

32 is a plan view showing a main part of a ladder filter serving as an electronic component constructed using a piezoelectric resonator according to preferred embodiments of the present invention. 33 is an exploded perspective view of this main part. In the electronic component 60 shown in FIGS. 32 and 33, four pattern electrodes 90, 92, 94, and 96 are formed on an insulator substrate 62 serving as a supporting member. Five lands arranged in a row at predetermined intervals are formed on the pattern electrodes 90, 92, 94 and 96. The first land portion closest to one end side of the insulator substrate 62 is disposed on the pattern electrode 90, the second land portion and the fifth land portion are disposed on the pattern electrode 92, and the third land portion is disposed on the pattern electrode 94. The land portion is disposed on the pattern electrode 96. The mounting member is formed on five land portions using a conductive adhesive, and is arranged as follows. One projection 98 in the first land portion, two projections 100 and 102 in the second land portion, two projections 104 and 106 in the third land portion, two projections 108 and 110 in the fourth land portion, One protrusion 112 is formed in the fifth land portion. These projections 98, 100, 102, 104, 106, 108, 110 and 112 are preferably arranged in a line at predetermined intervals.

The projections 98, 100, 102, 104, 106, 108, 110 and 112 are mounted with external electrodes 20 and 22 of piezoelectric resonators 10a, 10b, 10c and 10d, respectively. As the piezoelectric resonators 10a to 10d, for example, piezoelectric resonators 10 having external electrodes 20 and 22 formed on both sides of the base member 12 as shown in FIGS. 1 and 2 or 16 are used.

The projections 98, 100, 102, 104, 106, 108, 110 and 112 may be formed in advance on the piezoelectric resonators 10a, 10b, 10c and 10d. Further, the projections 98, 100, 102, 104, 106, 108, 110 and 112 are connected to the land portions of the pattern electrodes 90, 92, 94 and 96 and the external electrodes 20 and 22 of the piezoelectric resonators 10a to 10d. , 102, 104, 106, 108, 110, 112 can be bonded with the same kind or a different kind of conductive adhesive to the conductive adhesive. This also applies to electronic parts other than the electronic parts shown in FIGS. 32 and 33. Next, a metal cap (not shown) is disposed on the insulator substrate 62.

The electronic components shown in FIGS. 32 and 33 are used as ladder filters having a ladder-shaped circuit shown in FIG. The two piezoelectric resonators 10a and 10c act as series resonators, and the other two piezoelectric resonators 10b and 10d act as parallel resonators. In such a ladder filter, the parallel piezoelectric resonators 10b and 10d are designed to have substantially larger capacitance than the series piezoelectric resonators 10a and 10c.

The amount of attenuation in the ladder filter is determined by the capacity ratio between the series resonator and the parallel resonator. In the electronic component 60 shown in FIGS. 32 and 33, the capacitance can be adjusted by changing the number of stacked layers used in the piezoelectric resonators 10a to 10d. Therefore, a ladder filter having a large amount of attenuation with a smaller number of resonators is realized by changing the capacitance of the piezoelectric resonators 10a to 10d, and compared with the case of using a conventional non-rigid piezoelectric resonator. In addition, since the piezoelectric resonators 10a to 10d have a larger frequency difference ΔF than the conventional piezoelectric resonators, a wider transmission bandwidth is realized than in the case of using the conventional piezoelectric resonators.

In the electronic component 60 shown in Figs. 32 and 33, since two electrodes of adjacent piezoelectric resonators are mounted on two protrusions disposed in the same land portion, the two electrodes of adjacent piezoelectric resonators need to be insulated. There will be no. Therefore, as the adjacent piezoelectric resonators can be disposed very close to each other, the size of the electronic component can be substantially reduced, thereby miniaturizing.

35 is a plan view showing the main part of another ladder filter acting as an electronic component using a piezoelectric resonator according to a preferred embodiment of the present invention. 36 is an exploded perspective view of this main part. The electronic components shown in FIGS. 35 and 36 are particularly for piezoelectric resonators 10a, 10b, 10c, 10d, for example in FIG. 9 or 19, in comparison with the electronic components shown in FIGS. 32 and 33. The use of the piezoelectric resonator 10 in which the external electrodes 20 and 22 are formed on one side of the base member 12 as shown is different. The electronic components shown in FIGS. 35 and 36 also achieve the same advantages as the electronic components shown in FIGS. 32 and 33.

Each electronic component described above is preferably configured in a chip shape, but in other preferred embodiments of the present invention, the electronic component may be configured in a shape other than the chip shape.

In each of the piezoelectric resonators 10 described above, the plurality of piezoelectric layers 14 are preferably polarized alternately in opposite directions, but the polarization directions of the plurality of piezoelectric layers 14 are not limited to this arrangement.

In each of the piezoelectric resonators 10 described above, the respective dimensions of the piezoelectric layer 14 in the longitudinal direction of the base member 12 or the intervals between the adjacent internal electrodes 16 and 18 are preferably the same, but in other preferred embodiments, the above-described angles The dimensions and the intervals do not have to be the same.

In each of the piezoelectric resonators 10 described above, one piezoelectric layer 14 is disposed between adjacent internal electrodes 16 and 18, but a plurality of piezoelectric layers may be disposed between internal electrodes 16 and 18.

In each of the piezoelectric resonators 10 described above, the internal electrodes 16 and 18 connected to the external electrodes 20 and 22 are alternately formed, but in another preferred embodiment, the internal electrodes 16 and 18 may not be alternately formed.

As described above, the present invention is a piezoelectric resonator having a small spurious resonance, a large frequency difference ΔF between the resonant frequency and the anti-resonant frequency, easy to miniaturize, and prevents breakage and damage of external electrodes, and such a novel method. An electronic component having a piezoelectric resonator is provided.

Although the present invention has been shown and described, particularly with reference to preferred embodiments thereof, it will be understood that various changes and modifications can be made by those skilled in the art without departing from the scope of the invention. .

Claims (21)

A base member having a longitudinal direction; A plurality of internal electrodes disposed substantially perpendicular to the length direction of the base member at intervals in the length direction of the base member; And A piezoelectric resonator comprising a first external electrode and a second external electrode arranged on the surface of the base member and connected to the plurality of internal electrodes described above, The base member includes a plurality of laminated piezoelectric layers; The plurality of piezoelectric layers are polarized in the longitudinal direction of the base member; The plurality of internal electrodes are disposed on the surfaces of the plurality of piezoelectric layers so as to be substantially orthogonal to the longitudinal direction of the base member; The first group of the plurality of internal electrodes is connected to the first external electrode and arranged not to be exposed to a portion of the base member on which the second external electrode is disposed; And the second group of the plurality of internal electrodes is connected to the second external electrode and arranged not to be exposed to a portion of the base member on which the first external electrode is disposed. The method of claim 1, wherein one of the center axis and the center point of the shape formed by stacking the adjacent internal electrodes is one of the center axis and the center point of the base member in a plane substantially perpendicular to the longitudinal direction of the base member. Piezoelectric resonator substantially coincident with. The piezoelectric resonator of claim 1, wherein each of the first and second external electrodes is disposed on the other side of the base member. The piezoelectric resonator according to claim 1, wherein the first and second external electrodes are formed on one common side of the base member. The piezoelectric resonator of claim 1, further comprising a mounting member disposed between the support member and the center portion of the base member and the support member along the longitudinal direction of the base member. 2. The piezoelectric resonator of claim 1, wherein the piezoelectric resonator vibrates in a longitudinal vibration mode; And the first and second external electrodes extend along a longitudinal direction of the base member at one side of the base member. 7. The groove of claim 6, wherein a groove is formed along the longitudinal direction of the base member in a center portion in the width direction from the side of the base member on which the first and second external electrodes are disposed. The electrode is disposed on the first side and the second side divided by the groove on the side of the base member. 8. The piezoelectric resonator of claim 7, wherein each of the first and second groups of internal electrodes includes a plurality of the internal electrodes. The piezoelectric resonator according to claim 8, further comprising a mounting member disposed substantially in the center portion in the longitudinal direction of the base member. An electronic component using the piezoelectric resonator of claim 9, An electrode is formed and a substrate on which the base member is mounted by the mounting member; And And a cap disposed on said substrate so as to cover said base member. In the electronic component using the piezoelectric resonator of claim 1, A plurality of base members and a substrate, on which electrodes and a plurality of base members are disposed, arranged to form a ladder filter; And And a cap disposed on said substrate so as to cover said base member. A base member having a longitudinal direction; A plurality of internal electrodes disposed substantially perpendicular to the longitudinal direction of the base member at intervals in the longitudinal direction of the base member; And A piezoelectric resonator comprising a first external electrode and a second external electrode disposed on at least one surface of the base member and connected to the plurality of internal electrodes, The first group of the plurality of internal electrodes is connected to the first external electrode and arranged not to be exposed to a portion of the base member on which the second external electrode is disposed; And the second group of the plurality of internal electrodes is connected to the second external electrode and arranged not to be exposed to a portion of the base member on which the first external electrode is disposed. 13. The piezoelectric resonator of claim 12, wherein the outer surface of the base member includes only the external electrode. 13. The piezoelectric resonator according to claim 12, wherein the outer surface of the base member is not made of a resin material. 13. The piezoelectric resonator according to claim 12, wherein the first and second external electrodes are disposed on the other side of the base member. 13. The piezoelectric resonator according to claim 12, wherein the first and second external electrodes are disposed on one common side of the base member. 13. The piezoelectric resonator according to claim 12, wherein the base member is polarized along the longitudinal direction. 13. The piezoelectric resonator of claim 12, wherein the base member includes at least one piezoelectric active portion and at least one piezoelectric inactive portion. The method of claim 12, wherein the groove is formed along the longitudinal direction of the base member, wherein the first and second external electrodes are formed on one common side of the base member, wherein the groove is A piezoelectric resonator, characterized in that disposed between the first and second external electrodes. A base member having a longitudinal direction; A plurality of internal electrodes disposed substantially perpendicular to the longitudinal direction of the base member at intervals in the longitudinal direction of the base member; And a piezoelectric resonator including a first external electrode and a second external electrode connected to the plurality of internal electrodes on the surface of the base member. And An electronic component comprising a support member and a mounting member disposed between the central portion of the base member and the support member in the longitudinal direction of the base member. The base member includes a plurality of laminated piezoelectric layers; The plurality of piezoelectric layers are polarized in the longitudinal direction of the base member; The plurality of internal electrodes are disposed on a surface of the plurality of piezoelectric layers so as to be substantially orthogonal to the longitudinal direction of the base member; The first group of the plurality of internal electrodes is connected to the first external electrode and arranged not to be exposed to a portion of the base member on which the second external electrode is disposed; The second group of the plurality of internal electrodes is connected to the second external electrode and arranged not to be exposed to a portion of the base member on which the first external electrode is disposed; The support member includes an insulator substrate on which a pattern electrode is formed; The base member is mounted on the insulator substrate by the mounting member; An electronic component, wherein a cap is disposed on the insulator substrate so as to cover the base member. A base member having a longitudinal direction; A plurality of internal electrodes disposed substantially perpendicular to the longitudinal direction of the base member at intervals in the longitudinal direction of the base member; And a plurality of piezoelectric resonators each having a first external electrode and a second external electrode disposed on the surface of the base member to be connected to the plurality of internal electrodes. And An electronic component comprising a support member and a mounting member disposed between the central portion of the base member and the support member in the longitudinal direction of the base member. The base member includes a plurality of laminated piezoelectric layers; The plurality of piezoelectric layers are polarized in the longitudinal direction of the base member; The plurality of internal electrodes are disposed on a surface of the plurality of piezoelectric layers so as to be substantially orthogonal to the longitudinal direction of the base member; The first group of the plurality of internal electrodes is connected to the first external electrode and arranged not to be exposed to a portion of the base member on which the second external electrode is disposed; The second group of the plurality of internal electrodes is connected to the second external electrode and arranged not to be exposed to a portion of the base member on which the first external electrode is disposed; The support member includes an insulator substrate on which a pattern electrode is formed; The base member is mounted on the insulator substrate by the mounting member; A ladder filter, wherein a cap is disposed on the insulator substrate so as to cover the base member.