JP3114521B2 - Ladder type filter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ladder filter in which at least one series resonator and at least one parallel resonator are connected like a ladder, and more particularly, to a series resonator and a parallel resonator. The present invention relates to a ladder filter having an improved resonator structure.

[0002]

2. Description of the Related Art FIG. 1 shows an example of the structure of a conventional ladder filter. This ladder-type filter is configured by using a plurality of piezoelectric resonators utilizing a spread vibration mode of a square plate. That is, a four-element two-stage ladder filter shown in the circuit diagram of FIG. 2 is configured by using the rectangular plate-shaped series resonators 1 and 2 and the rectangular plate-shaped parallel resonators 3 and 4.

In FIG. 1, reference numeral 2a denotes an electrode formed on one main surface of the series resonator, and a similar electrode is formed on the other main surface of the series resonator 2. Similar electrodes are formed on both main surfaces of the series resonator 1.
On the other hand, the parallel resonators 3 and 4 have electrodes 3
a, 4a are formed.

[0004] Reference numerals 5 to 11 denote metal terminals, which are used to electrically connect the series resonators 1 and 2 and the parallel resonators 3 and 4 to each other as shown in FIG. The metal terminals 5 to 11 are housed together with the series resonators 1 and 2 and the parallel resonators 3 and 4 in a case member 12 made of an insulating material. Further, the upper opening 12a of the case member 12 is closed by a lid member (not shown) to form a ladder-type filter component. In this case, the metal terminals 9 to 11 are drawn out of the case and used as connection terminals with the outside.

When the ladder-type filter is driven, it is necessary that the series resonators 1 and 2 and the parallel resonators 3 and 4 can vibrate in a desired manner while being housed in a case. That is, in the state stored in the case,
The vibration of each resonator 1-4 must not be disturbed. Therefore, a so-called spring terminal having a spring property is used as the metal terminal 11 located at the end.

In the ladder-type filter shown in FIG. 1, since a spring terminal is used as the metal terminal 11 so as not to hinder the vibration of the resonators 1 to 4 housed in the case, a considerable unnecessary space is formed. Therefore, the size of the entire ladder-type filter tends to be considerably large. For example, in the illustrated two-stage ladder-type filter with four built-in elements, the dimensions when configured as final components are as follows.
The size was about 0 mm x 8.0 mm x thickness 8.0 mm.

In recent years, like other electronic components, there has been a demand for a ladder-type filter configured as a surface-mounted electronic component. Therefore, International Application Publication No. W
O92 / 16997 proposes a ladder-type filter that can be reduced in overall shape and configured as a surface-mounted electronic component. In this ladder-type filter, the series resonator and the parallel resonator are each formed of a tuning-fork type piezoelectric resonator having a tuning-fork-shaped vibrating portion at one edge of the piezoelectric plate. Then, a plurality of tuning-fork type piezoelectric resonators constituting the series resonator and the parallel resonator are stacked and integrally formed via a cavity forming material for securing a cavity for not hindering the vibration of the tuning-fork vibrating portions. Has been

[0008]

The ladder-type filter using the tuning-fork type piezoelectric resonator described above can simplify the assembling process, reduce the size, and achieve surface mounting. However, since the tuning fork type piezoelectric resonator is used,
There is a problem that a sufficient bandwidth cannot be secured.

An object of the present invention is to provide a ladder-type filter capable of not only simplifying the manufacturing process, reducing the size and realizing surface mounting, but also securing a sufficient bandwidth.

[0010]

According to a broad aspect of the present invention, there is provided at least one series resonator forming a series arm and at least one parallel resonator forming a parallel arm, A ladder-type filter is provided in which at least two resonators of a series resonator and a parallel resonator are stacked in a thickness direction.

[0011] As the upper Symbol co pendulum, it can be used various ones. The first type of upper Symbol co pendulum, the length of the short side is a, the length of the long side is b, and Poisson's ratio of the material constituting the piezoelectric vibrating portion is taken as sigma, long side And the ratio of the short side length b / a is

[0012]

(Equation 5)

A rectangular plate-shaped piezoelectric vibrating portion, a supporting portion connected to the center of the short side of the piezoelectric vibrating portion, and a range of ± 10% (where n is an integer) around the center. A holding portion connected to an outer end of the support portion, and
A pressure conductive resonator utilizing a width expansion mode in which the width direction.

The width expansion mode is one of the vibration modes of the rectangular plate-shaped vibrator, as will be apparent from the embodiments described later.
This is a vibration mode that takes a vibration mode between a spread mode vibration of a vibrating body of a square plate and a width mode vibration of a vibrating body of a rectangular plate.

In the above-described piezoelectric resonator utilizing the width expansion mode, the vibration energy of the piezoelectric vibrating portion can be confined and supported by simply fixing or integrally forming the supporting portion at the center of the short side of the piezoelectric vibrating portion. Therefore, the support structure can be simplified. Therefore, a small ladder-type filter can be configured by combining with another resonator using the holding portion provided outside the supporting portion. In addition, since the piezoelectric vibrating portion is vibrated in the widening mode, it is possible to obtain a ladder-type filter having a wider band than in the related art.

According to a specific aspect of the present invention, in the piezoelectric vibrating portion utilizing the width expansion mode, a ratio of a short side to a long side of the rectangular plate-shaped piezoelectric vibrating portion is set within the above specific range. By doing so, the widening mode is efficiently excited and confined. This has been experimentally confirmed by the present inventor.

[0017] In addition, the second of the type of the above Ki圧 electric resonator,
A plate-shaped piezoelectric body polarized in one direction, and first and second resonance electrodes formed on the piezoelectric body to apply an AC voltage in a direction orthogonal to the polarization direction; When the piezoelectric body surface parallel to the polarization direction has a rectangular shape, the length of the short side of the rectangular piezoelectric body surface is a, the length of the long side is b, and the Poisson's ratio of the piezoelectric body is σ. The ratio b / a is

[0018]

(Equation 6)

A sliding mode is provided, which includes a piezoelectric vibrating portion having a range of ± 10% with respect to the center, a supporting portion connected to the piezoelectric vibrating portion, and a holding portion connected to the supporting portion. and a pressure conductive resonator.

In the second type of piezoelectric resonator, since the piezoelectric vibrating portion is configured to have the above-described specific shape, an AC voltage is applied between the first and second resonance electrodes to cause the piezoelectric vibrating portion to have a specific shape. Is resonated, vibration energy is effectively confined in the piezoelectric vibrating portion. This phenomenon has been experimentally confirmed by the present inventor.

[0021] In the second type of pressure conductive resonator, since the vibrational energy to the piezoelectric vibrating portion as described above it is effectively trapped, pressure type second using a holding portion <br/> An electric resonator can be supported, and even in such a case, deterioration of resonance characteristics hardly occurs. Therefore, a small ladder-type filter can be easily configured by combining with another resonator using the holding unit. Further, since the resonator using the slip mode is used, it is easier to expand the band of the ladder filter as compared with the piezoelectric tuning fork resonator.

The third type of upper Ki圧 electric resonator comprises a pair of rectangular opposed faces, a piezoelectric vibrating portion plate-shaped with four sides connecting the pair of rectangular faces, the piezoelectric vibrating portion A first and a second resonance electrode formed on the pair of rectangular surfaces,
Of the side surfaces of the piezoelectric vibrating portion, a supporting portion connected to one end of a side surface along the short side of the rectangular surface, and a holding portion connected to the supporting portion, the length of the short side of the rectangular surface Is a, the length of the long side is b, and the Poisson's ratio of the material constituting the piezoelectric vibrating portion is σ, the ratio b / a is:

[0023]

(Equation 7)

A value within a range of ± 10% around a value satisfying (where n is an integer) is used to excite the vibration of the 2nd order (where n is an integer) bending mode using the piezoelectric transverse effect. a pressure conductive resonator that is configured to. Also in the third type of piezoelectric resonator, since the piezoelectric vibrating portion is configured to have the specific shape described above, the vibration of the 2n-th bending mode is effectively confined in the piezoelectric vibrating portion. This phenomenon has been experimentally confirmed by the present inventor.

Even in a ladder-type filter using a third type of piezoelectric resonator, the resonance energy is effectively confined in the piezoelectric vibrating section, so that the third type of piezoelectric resonator utilizes the holding section. It can be easily combined with other resonators or joined to a case substrate or the like, and even in this case, deterioration of resonance characteristics hardly occurs. Therefore, a small ladder-type filter having stable characteristics and capable of simplifying the support structure can be configured.

[0026] In addition, the fourth type of the above Ki圧 electric resonator,
An energy trap type piezoelectric resonator having a structure in which a dynamic vibration absorbing portion is provided between a piezoelectric vibrating portion and a support portion. Here, the vibration energy is effectively confined by the dynamic vibration absorbing portion to the portion where the dynamic vibration absorbing portion is provided due to the dynamic vibration absorbing phenomenon. For details of the dynamic vibration absorption phenomenon, see, for example, Osamu Taniguchi, “Vibration Engineering,” pp. 113-116 (issued by Corona).
It is described in. Simply put, the dynamic vibration absorption phenomenon means that the vibration of the main vibrating body is suppressed by connecting the sub-vibrating body to the main vibrating body whose vibration is to be prevented and selecting the natural frequency of the sub-vibrating body. The dynamic vibration absorbing section corresponds to a sub-vibration body in the dynamic vibration absorbing phenomenon, and a support section that vibrates due to vibration from a resonance section corresponds to a main moving body.

In the ladder-type filter using the fourth type of piezoelectric resonator, at least one resonator is composed of the piezoelectric resonator having the above-mentioned dynamic vibration absorbing portion, so that the efficiency of trapping vibration energy is improved. ing. Therefore, since the size of the piezoelectric resonator can be reduced, the size of the ladder filter can be reduced by using the piezoelectric resonator.

[0028] Note that the fourth type of pressure conductive resonator,
It is characterized by having a dynamic vibration absorbing portion as described above, and the piezoelectric vibrating portion itself is not particularly limited. That is, in the above-described piezoelectric resonators of the first to third types , by providing the dynamic vibration absorber, the slightly leaked vibration is suppressed by the dynamic vibration absorber, thereby further confining the energy. Efficiency can be increased. Alternatively, in the fourth type of pressure electric resonator, the piezoelectric vibrating unit utilizing other piezoelectric vibrating portion which is different from the first to the piezoelectric vibrating portion of the third type of pressure conductive resonators, for example, a length mode, slip A normal piezoelectric vibrating part using a mode, a piezoelectric vibrating part using a square plate spreading mode, or the like can be used as appropriate. That is, in the fourth type of pressure conductive resonator utilizing the dynamic vibration reducer unit, it is possible to use a piezoelectric vibrating unit is excited in different vibration modes in accordance with the desired resonant frequency, therefore, different frequencies A ladder-type filter that can be used in a band can be easily obtained.

[0029] Moreover, by providing the dynamic vibration reducer unit, since the parts in the vibration energy up dynamic vibration section is effectively confined, as in the case of pressure conductive resonators of the first to third types, the holding The piezoelectric resonator can be held by using the portion, and even in that case, the deterioration of the resonance characteristics hardly occurs. Accordingly, a small-sized ladder-type filter having stable characteristics can be easily configured.

According to a preferred aspect of the present invention, the supporting portion and the holding portion are connected to both sides of the piezoelectric vibrating portion. Therefore, the piezoelectric vibrating portion is supported on both sides by the supporting portion. A ladder-type filter having a more stable structure can be obtained. Further, in the structure in which the holding portions are arranged on both sides of the piezoelectric vibrating portion, since the piezoelectric resonator can be held using the holding portions arranged on both sides, the support structure is also stabilized.

Further, the ladder type filter of the present invention has a structure in which at least two resonators are stacked as described above. Specifically, such a laminated structure is configured, for example, by arranging the laminated structure between the first and second case substrates and sandwiching the laminated structure between the first and second case substrates. Thus, a chip-type ladder-type filter can be easily configured. Alternatively, a chip-type ladder-type filter may be formed by stacking the laminated structure on a base substrate and fixing a cap material to the base substrate so as to surround the laminated structure.

According to the present invention, as described above, at least one of the series resonators and the parallel resonators has a plate-shaped piezoelectric vibrating part, a supporting part, and a holding part. The resonator may be configured to have a plate-shaped piezoelectric vibrating section, a supporting section, and a holding section. In that case, all the resonators can be connected using the holding section, and the case Since it can be fixed to a substrate or the like, a chip-type ladder-type filter can be easily configured.

Preferably, according to the present invention, in the structure in which holding portions are provided on both sides of the piezoelectric resonator,
First and second spacer plates are provided on both sides in the direction connecting the holding parts on both sides. The first and second spacer plates are connected to the piezoelectric resonator so as not to hinder the vibration of the vibrating portion of the piezoelectric resonator, whereby the first and second spacer plates are connected to the first and second spacer plates.
The resonance plate is constituted by the spacer plate. When such a resonance plate is configured, a chip-type ladder-type filter having a laminated structure can be easily configured.

When the piezoelectric resonator and the first and second spacer plates forming the resonance plate are integrally formed by the same member, the space beside the resonator is reliably surrounded. Since it is bent, a ladder-type filter having excellent environmental resistance characteristics such as moisture resistance can be easily obtained.

In a structure in which holding portions are provided on both sides of at least one piezoelectric resonator, at least one other piezoelectric resonator is connected to the piezoelectric vibrating portions on at least one side in a direction connecting the holding portions on both sides. May be connected so as not to hinder the vibrations of the above. That is, in the ladder-type filter of the present invention, at a certain height position, two or more piezoelectric resonators may be connected on the same plane.

Further, at least one side of the piezoelectric resonator
In a structure in which the piezoelectric resonators are connected, the first and second spacer plates may be arranged on both sides of the connection structure to form a resonance plate. Also in this case, the piezoelectric resonator and the first and second spacer plates constituting the resonance plate may be integrally formed of the same material, whereby the sides of the plurality of piezoelectric resonators are surely formed. A ladder-type filter that can be sealed and has excellent environmental resistance such as moisture resistance can be formed.

Preferably, the piezoelectric vibrating portion is provided with first and second resonance electrodes for exciting the piezoelectric vibrating portion, and a lead electrode is formed on the holding portion. In this case, the first and second resonance electrodes are electrically connected to the extraction electrode. Therefore, the piezoelectric vibrating portion can resonate by electrically connecting the extraction electrode to the outside.

More preferably, a plurality of external electrodes are formed on the outer surface of the ladder-type filter of the present invention, and the plurality of external electrodes are electrically connected to the above-mentioned predetermined extraction electrode. Therefore, a ladder-type filter can be configured as a chip-type electronic component having a plurality of external electrodes.

According to another aspect of the present invention, there is provided a ladder-type filter including at least one series resonator forming a series arm and at least one parallel resonator forming a parallel arm. , At least one plate-shaped resonator,
At least one laminated on the at least one resonator
And at least one of the series resonator and the parallel resonator has a short side length a, a long side length b, and a piezoelectric element. When the Poisson's ratio of the material forming the vibrating portion is σ, the ratio b / a of the length of the long side to the length of the short side is within ± 10% around the above equation (1). A ladder-type filter is provided, which is a rectangular plate-shaped piezoelectric resonator and an energy trapping type piezoelectric resonator utilizing a widening mode. That is, the ladder-type filter is provided by a first type of energy-trap piezoelectric resonator that is constructed using only the piezoelectric vibrating part of the piezoelectric resonator described above. Preferably,
All the resonators of the series resonator and the parallel resonator are constituted by a piezoelectric resonator constituted by using only the piezoelectric vibrating portion of the above-described energy trap type piezoelectric resonator of the first type. Since there is no section or holding section, a ladder-type filter having a smaller size and a relatively simple shape can be provided.

In the above-described first to third types of energy trapping type piezoelectric resonators and the first type of energy trapping type piezoelectric resonators, only the piezoelectric vibrating portions of the piezoelectric resonator are used. As the piezoelectric material constituting the piezoelectric vibrating portion, in addition to piezoelectric ceramics, LiTaO
Piezoelectric single crystal such as ₃ or LiNbO ₃ and the like. Alternatively, a piezoelectric thin film may be provided on the surface of a metal plate, a semiconductor plate, or the like, and a piezoelectric vibrating portion may be formed by such a composite member. When the piezoelectric vibrating portion is configured using the composite member, the above-described Poisson ratio σ is selected in consideration of the Poisson ratio of the composite material.

[0041]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be clarified by describing non-limiting embodiments of the present invention.

<First Type of Energy Confinement Type Piezoelectric Resonator> First, a first type of piezoelectric resonator having a characteristic structure used in the present invention will be described, and thereafter, the first type of piezoelectric resonator will be described. A ladder-type filter using a piezoelectric resonator will be described.

FIG. 3 is a perspective view for explaining a piezoelectric vibrating portion in a first type of energy trap type piezoelectric resonator used in the present invention. In the piezoelectric resonator 205, electrodes 207 and 2 are provided on both main surfaces of a rectangular piezoelectric ceramic plate 206 which is polarized so that the polarization axes are aligned in the thickness direction.
08 is formed. When the length of the short side of the piezoelectric ceramic plate 206 is a and the length of the long side is b, b / a is
The specific range described above has been selected, which strongly excites the widening mode described below. Next, the ratio b
The reason why the width expansion mode is strongly excited when / a is in the above specific range will be described.

FIGS. 4 to 6 are schematic plan views showing vibration modes of the vibrating body for explaining the spreading mode, the width spreading mode and the width mode. The inventor of the present application analyzed the vibration state of the rectangular plate-shaped vibrator by changing the lengths of its short side and long side by the finite element method. When the ratio b / a of the length b of the long side to the length a of the short side is b / a = 1, that is, when the vibrating body is a square plate, the vibration in the expanding vibration mode is strongly excited as shown in FIG. Is done. That is, FIG.
In the vibrating body 201 having a square planar shape shown in (1), the vibration is repeated between the state shown by the broken line A and the state shown by the dashed line B, and the spreading mode is strongly excited.

When b / a is much larger than 1, that is, when b / a >> 1, as shown in FIG. It vibrates between the states shown, and the width mode vibration is strongly excited.

On the other hand, when the ratio = b / a is greater than 1 and the vibration in the width mode is smaller than the strong excitation, as indicated by the dashed line A in FIG. It was found that the vibration between the states shown by the broken line B, that is, the widening mode was strongly excited. The width expansion mode is considered to be an intermediate vibration mode between the known expansion mode and the width mode, and thus is named as the width expansion mode as described above.

Based on the above findings, the piezoelectric resonator shown in FIG. 3 was manufactured using a piezoelectric ceramic plate in which the ratio b / a was selected to a specific value. In the piezoelectric resonator 205, b
When the width expansion vibration mode was excited by changing / a variously, it was confirmed that the width expansion vibration mode was most strongly excited when b / a = -1.47σ + 1.88 was satisfied. When the displacement distribution in the piezoelectric resonator 205 in this case was analyzed by the finite element method, the result shown in FIG. 7A was obtained.

In the displacement distribution analyzed by the finite element method, as shown in FIG.
When the center of the main surface was defined as O, the x-axis and y-axis were defined as shown, and the displacement state of each part was measured, the result shown in FIG. 8 was obtained. In other words, the piezoelectric resonator 205 that the width expansion mode is excited, the position along the X-axis direction, the amount of displacement and the center O, minimum at X ₁ i.e. short side center in FIG. 7 (b), the his It can be seen that the displacement amount is the largest in the middle. This means that in the piezoelectric resonator 205 using the widening mode, the node points are located at the center of the main surface and the center of the short side. Therefore, it can be seen that by supporting the center of the main surface or the center of the short side with another supporting member, the piezoelectric resonator 205 can be supported without obstructing the width expansion mode.

The ratio b / a is determined by the piezoelectric resonator 205
It was confirmed that it was related to the Poisson's ratio. That is, by changing the Poisson's ratio of the vibrating body, the ratio b / a when the above-mentioned widening vibration mode is excited is measured, and
When the value of / a was plotted, the result shown in FIG. 9 was obtained. Therefore, as shown by the straight line in FIG.

[0050]

(Equation 8)

It has been found that by selecting the ratio b / a so as to satisfy the condition, the widening vibration mode can be surely excited.

Further, the widening vibration mode is not strongly excited only when the ratio b / a satisfies the equation (4), but the widening vibration mode is not excited even when slightly deviating from the above equation (4). Since it was found that the excitation was strong, the presence or absence of excitation of the width-expanded vibration mode was confirmed by changing the ratio b / a using a piezoelectric ceramic plate having a Poisson's ratio σ = 0.324. That is, the displacement at point X ₁ in FIG. 7B is D (X ₁ ), the displacement at point C (see FIG. 7) where the displacement is the largest in the width expansion mode is D (C), and the point X Relative displacement D (X ₁ ) / D of point ₁ to point C
(C) was measured. The results are shown in FIG.

As is apparent from FIG. 10, the Poisson's ratio σ
In the case of = 0.324, it can be seen that the relative displacement is within ± 10% if the ratio b / a is within the range of 1.26 to 1.54. Therefore, as described above, the ratio b / a is ±
The piezoelectric resonator 205 shown in FIG.
Were prepared, and a supporting member was connected to the center of the short side to measure resonance characteristics. As a result, as described above, the relative displacement is 1
It was confirmed that in the case of 0% or less, the widening mode was well confined.

Therefore, as shown in FIG.
It can be seen that if a is set within a range of ± 10% around a point satisfying the expression (4), it can be understood that the above-mentioned widened vibration mode can be favorably excited. Also, (−1.47σ + 1.
88), it was found that even when n times (n is an integer) the width-spread vibration mode is favorably excited.

FIGS. 12A and 12B are a plan view and a front view showing an example of a piezoelectric resonator using the width expansion mode manufactured based on the above findings, ie, a first type of piezoelectric resonator. is there. The piezoelectric resonator 211 has a piezoelectric vibrating section 212 as a rectangular plate-shaped vibrating body. The piezoelectric vibrating portion 212 has a rectangular planar shape, and has a structure in which resonance electrodes 214 and 215 are formed on both surfaces of a piezoelectric ceramic plate 213 uniformly polarized in the thickness direction. The supporting member 21 is located at the center of the short side, which is the node point when the piezoelectric vibrating portion 212 is excited in the widening vibration mode.
6,217 are connected. And the support member 21
6 and 217 have holding portions 218 and
219 are connected.

The support members 216 and 217 and the holding portions 218 and 219 are formed integrally with the piezoelectric ceramic plate 213. That is, it is formed by preparing a rectangular piezoelectric ceramic plate and machining it to have the shape shown in FIG. However, the support members 216 and 217 and the holding portions 218 and 219 may be formed as members separate from the piezoelectric vibrating portion 212, and may be connected as shown by an appropriate method such as adhesion. Good.

The resonance electrodes 214 and 215 are held by holding conductive parts 214 a and 215 a formed on one surface of the supporting members 216 and 217, respectively.
Extraction electrodes 220 and 22 formed on one main surface of
1 electrically.

In the piezoelectric resonator 211, the extraction electrode 22
By applying an AC voltage from 0 and 221, the piezoelectric vibrating section 212 is excited in the widening mode. In this case, the center of the short side of the piezoelectric vibrating portion 212 hardly vibrates,
Since the central portion of the short side of the piezoelectric vibrating portion 212 forms a vibration node point, even in the case where the support members 216 and 217 are connected, vibration in the widening mode is not easily disturbed.
Therefore, it is possible to effectively confine the vibration based on the width expansion mode between the support members 216 and 217.

The size of the piezoelectric vibrating section 212 is set to be 2.5 mm wide × 3.5 m long by using a piezoelectric ceramic plate.
m, the resonance frequency is 800 kHz and the width is 1.0
Since the frequency is 2 MHz when mm × 1.4 mm, it has been found that an energy trap type piezoelectric resonator suitable for use in the 800 kHz to 2 MHz band can be formed.

However, as for the above-mentioned resonance frequency, when the piezoelectric resonance part is made of another material, the effective frequency band naturally changes. Therefore, by forming the piezoelectric vibrating portion 212 from various piezoelectric materials, the energy trap type piezoelectric resonator 2 suitable for use in various frequency bands is provided.
11 can be obtained.

FIG. 13 shows another example of an energy trap type piezo-resonator utilizing a widening mode. The piezoelectric resonator 231 has a piezoelectric vibrating part 232 as a rectangular plate-shaped vibrating body. However, in the piezoelectric vibrating part 232, a pair of resonance electrodes 232b and 232c are formed on the upper surface of the piezoelectric plate 232a along the long side edge. The piezoelectric plate 232a is polarized in a direction indicated by an arrow P, that is, in a direction from the resonance electrode 232b to the resonance electrode 232c. Also in this example, the ratio b of the length b of the long side of the piezoelectric vibrating portion 232 to the length a of the short side is
/ A is set within a range of ± 10% around a point satisfying the expression (1).

Accordingly, when an AC voltage is applied between the resonance electrodes 232b and 232c, the piezoelectric vibrating portion 232 vibrates in the width expansion mode. In this case, since the direction of displacement of the piezoelectric vibrating portion 232 is parallel to the applied electric field, a piezoelectric resonator utilizing the piezoelectric longitudinal effect is provided.

Also, in the piezoelectric resonator 231 of this embodiment, the support members 236 and 237 are connected to the nodes of the vibration of the piezoelectric vibrating portion 232 that resonates in the above-described widening mode. Holder 23 at end
8,239 are connected. In FIG. 13,
Reference numerals 234a and 235a denote lead-out conductive parts, 240 and 241
Indicates an extraction electrode.

As is clear from the example shown in FIG. 13, the resonator using the width expansion mode in the present invention is applied not only to the one utilizing the piezoelectric lateral effect but also to the one utilizing the piezoelectric longitudinal effect. be able to.

FIG. 14 is a plan view showing still another example of the energy trap type piezoelectric resonator using the widening mode used in the present invention. The piezoelectric resonator 251 shown in FIG. 14 is characterized in that a dynamic vibration absorbing part and a connecting part are provided, and the other points are the same as those of the energy trap type piezoelectric resonator 211 shown in FIG. Therefore, the same portions are denoted by the same reference numerals, and description thereof will be omitted.

The dynamic vibration absorbing portions 252 and 253 are
6,217, and is configured as a bar-shaped portion extending vertically. Dynamic vibration absorbers 252, 25
3, the connecting portion 2 is located between the holding portions 218 and 219.
54, 255 are constituted.

Since the supporting members 216 and 217 are connected to the vibration nodes of the piezoelectric resonance section 212, the supporting members 2
The leakage of vibration to the 16, 217 side is very small. However, in this example, the vibrations that have leaked slightly resonate the dynamic vibration absorbers 252 and 253, thereby suppressing the vibration that has leaked slightly. Therefore, vibration energy can be effectively confined to the portions up to the dynamic vibration absorbing portions 252 and 253. Therefore, a more compact piezoelectric resonator can be configured.

The piezoelectric resonator 251 shown in FIG. 14 has one feature in that the dynamic vibration absorbing portion is provided as described above. Therefore, the fourth type of energy trapping type used in the ladder type filter of the present invention is used. It is also an example of a piezoelectric resonator.

<Second Type Piezoelectric Resonator> FIGS. 15 and 16 illustrate a piezoelectric resonator (second type piezoelectric resonator) using an energy trap type slip mode used in the present invention. It is a side view and a perspective view for.

The piezo-resonator 311 is configured using a piezo-electric ceramic plate 312 in the shape of a rectangular plate. The piezoelectric ceramic plate 312 is polarized so that the polarization axes are aligned in a direction parallel to the main surface, that is, in the direction of the arrow P in the drawing.

On the upper surface 312a of the piezoelectric ceramic plate 312, a first resonance electrode 313 is formed from one end face 312c to the other end face 312d, but not to the other end face 312d. Similarly, on the lower surface 312b of the piezoelectric ceramic plate 312,
From the d side toward the end face 312c side,
The second resonance electrode 314 is formed so as not to reach c.

The upper surface 31 of the piezoelectric ceramic plate 312
2a, a first groove 315 extending in the width direction is provided on the lower surface 31.
A second groove 316 extending in the width direction is also formed on 2b. Then, in the piezoelectric ceramic plate portion sandwiched between the first groove 315 and the second groove 316, the upper and lower first and
The second resonance electrodes 313 and 314 are the piezoelectric ceramic plates 31
2 overlap with each other to form a piezoelectric vibrating part. That is, the first and second resonance electrodes 3
13 and 314, the first and second grooves 3 respectively.
15 and 316 are formed, and the first and second grooves 315 and 3 are formed.
A resonance portion is formed between the sixteen. Therefore, the first and second
When an AC voltage is applied between the resonance electrodes 313 and 314 to vibrate the piezoelectric vibrating portion, the vibration in the slip mode is strongly excited, and the vibration in the slip mode is generated by the first and second grooves 31.
Since 5,316 is formed, it is effectively confined in the piezoelectric vibrating portion.

In the piezoelectric resonator 311, the grooves 315,
The portion between 316 constitutes a piezoelectric vibrating portion, and the portion of the piezoelectric plate below the groove 315 and the portion of the piezoelectric plate above the groove 316 constitute a support portion in the present invention. Also, grooves 315, 31
The portion of the piezoelectric plate outside the portion 6 constitutes the holding portion in the present invention. Further, the resonance electrodes 313 and 314 function as electrodes for resonating the piezoelectric vibrating portion in a portion existing in the piezoelectric vibrating portion, but function as the above-described extraction electrode in a portion reaching the holding portion.

In the piezoelectric resonator 311, the direction of the piezoelectric body surface parallel to the polarization direction of the piezoelectric vibrating portion is defined by the longer side of the length b and the length a.
And has a short side. Assuming that the Poisson's ratio of the piezoelectric material forming the piezoelectric ceramic plate 312 is σ, the ratio b / a is within a range of ± 10% around a value satisfying the expression (2). In other words, the ratio b
/ A is within the above-mentioned specific range so that the groove 31
5,316, which define the dimensions of the piezoelectric vibrating part.

In the piezoelectric resonator 311, the ratio b / a
It has been experimentally confirmed by the inventor of the present invention that the vibration energy due to the slip mode is more effectively confined in the piezoelectric vibrating portion if the ratio is within the above specific range. This is then shown in FIGS.
This will be described with reference to FIG.

Now, as shown in the side view of FIG. 17A, the piezoelectric body 32 which has been polarized in the direction of arrow P, ie, the direction parallel to the upper and lower surfaces, and has a ratio b / a = 1.
Assume a structure in which the resonance electrodes 322 and 323 are formed on both main surfaces of No. 1. In this case, by applying an AC voltage from the resonance electrodes 322 and 323, the piezoelectric body 321 vibrates in a ring-and-slip mode. As a result, it vibrates between the vibration mode shown by the broken line A in the figure and the vibration mode that is symmetrical to the vibration mode shown by the broken line A.

The position of each part of the vibrating body 321 is shown in FIG.
FIG. 7B shows an xy coordinate system. In this case, at the time of vibration, the corner portion A shows the largest displacement in both the x direction and the y direction. The point O, which is the center of the piezoelectric body 321, is a node point of vibration. On the other hand, the piezoelectric body 32
Displacement is also observed at the points O ₁ and O ₂ at the intermediate height on the side surface of the first side.

Accordingly, since displacement is observed also at the points O ₁ and O ₂ , a ring-shaped sliding mode resonator having a shape in which a piezoelectric plate is further formed outside both side surfaces of the piezoelectric body 321 is formed. In this case, the efficiency of confining vibration energy is not sufficient. In contrast, the ratio b / a
To

[0079]

(Equation 9)

It was found that the displacement distribution was as shown in FIG. That is, the piezoelectric body 331 shown in a schematic side view in FIG. 18 vibrates between a vibration mode shown by a broken line B and a vibration mode that is symmetrical to the vibration mode. In this case, the displacement vector on the short side has only the component in the x direction as shown in FIG. In the side surfaces 331a and 331b of the piezoelectric body 331, the displacement direction is reversed between the upper half and the lower half.

Therefore, the displacement state of the structure in which the support was connected to the piezoelectric body was examined by changing the above b / a variously and using various piezoelectric materials. As a result, it was confirmed that there is a relationship shown in FIG. 19 between the Poisson's ratio σ of the piezoelectric material used and the ratio b / a. From the results of FIG. 19, by setting the ratio b / a so as to satisfy the expression (5), it is possible to reduce the transmission of the displacement to the support body side, in other words,
It was found that the vibration energy could be effectively confined in the piezoelectric vibrating part.

When the ratio b / a is (0.3σ + 1.
48), it was confirmed that vibration energy can be effectively confined even in the case of n times (where n is an integer). As described above, it was found that the vibration can be confined in the piezoelectric vibrating section by selecting the dimensions of the piezoelectric vibrating section so as to satisfy the expression (2). Based on this result, the support portions 342A and 34 are provided on the piezoelectric vibrating portion 341 when a piezoelectric material having a Poisson's ratio σ = 0.31 and b / a = 1.57 is used.
When the displacement distribution of the resonator integrally formed with the supporting portions 344 and 345 having the same width as the piezoelectric vibrating portion 341 via 3A was examined by the finite element method, the result shown in FIG. 20 was obtained.

As is apparent from FIG. 20, this resonator 3
At 46, it can be seen that the vibration energy in the slip mode in the piezoelectric vibrating portion 341 hardly leaks to the support portions 342A and 343A side. That is, by selecting the ratio b / a so as to satisfy Expression (2),
It can be seen that a resonator using a slip mode having high energy confinement efficiency can be formed.

Next, at a certain Poisson's ratio σ, n in the above equation (2) is changed from 0.85 to 1.1, and the displacement amount of the point P having the largest displacement amount shown in FIG. The ratio of the amount of displacement at the small point Q, that is, the relative displacement (%) was measured. The results are shown in FIG.

As is apparent from FIG. 21, when the value of n is 0.
In the range of 9 to 1.1, it is understood that the relative displacement is 10% or less. On the other hand, it has been found that when the relative displacement is 10% or less, there is substantially no problem in forming the resonator. Therefore, ± 10 from the value satisfying the expression (2)
%, The vibration energy can be effectively confined in the resonance part.

Therefore, in the piezoelectric resonator 311 of the second type shown in FIGS. 15 and 16, the thickness a of the piezoelectric ceramic plate of the piezoelectric vibrating portion and the length dimension b of the resonance portion along the polarization direction P, ie, the piezoelectric The length a of the short side and the length b of the long side of the rectangular piezoelectric body surface parallel to the polarization direction of the vibrating part are set to be within ± 10% from the value represented by the above equation (2). The first and second grooves 315 and 316 are formed, thereby increasing the energy confinement efficiency.

FIG. 22 is a side view showing another example of the second type piezoelectric resonator. In the piezoelectric resonator 351, a third groove 357 is further formed outside the first groove 355 on the upper surface 352a of the piezoelectric ceramic plate 352 polarized in the direction of the arrow P. Of the second groove 356 on the lower surface 352b side of the
A fourth groove 358 is formed on the outside of the groove, thereby forming first and second dynamic vibration absorbing portions 359 and 360. The dynamic vibration absorbing portions 359 and 360 resonate with the leaked vibration due to a known dynamic vibration absorbing phenomenon, and act to cancel the leaked vibration. Therefore, the dynamic vibration absorber 3
The dimensions of 59 and 360 are selected so as to cancel the vibration due to the dynamic vibration absorption phenomenon.

In the piezoelectric resonator 351, the third and fourth grooves 357 and 358 are formed so that the dynamic vibration absorbing parts 359 and 360 are formed.
Since the configuration is the same as that of the piezoelectric resonator 311 except for the configuration, the other parts are given the same reference numerals, and the description thereof is omitted.

In the piezoelectric resonator 351, since the ratio b / a in the resonating portion is within a range of ± 10% from the value represented by the equation (2), vibration energy is effectively confined in the resonating portion. Moreover, the slightly leaked vibration is canceled by the dynamic vibration absorbing portions 359 and 360 due to the dynamic vibration absorbing phenomenon. Therefore, when the piezoelectric resonator 351 is mechanically held in the holding portions 361 and 362 outside the third and fourth grooves 357 and 358, the deterioration of resonance characteristics hardly occurs. Therefore, the energy confinement efficiency can be further increased as compared with the piezoelectric resonator 311, and a smaller piezoelectric resonator can be provided. Note that the piezoelectric resonator 3
51 has the dynamic vibration absorbing portions 359 and 360 as described above, and thus is also a fourth type piezoelectric resonator used in the present invention.

FIG. 23 is a perspective view showing still another example of the energy trap type piezoelectric resonator of the second type.
The piezoelectric resonator 371 is configured by using an elongated rectangular piezoelectric ceramic plate 372 that has been polarized along the longitudinal direction P. In the piezoelectric ceramic plate 372, the piezoelectric plate 372
The first and second resonance electrodes 373 and 374 are formed along the both side edges on the upper surface of the. Further, grooves 375 and 376 are formed on both side edges, respectively. The portion of the piezoelectric plate sandwiched between the grooves 375 and 376 constitutes a piezoelectric vibrating portion. This piezoelectric vibrating portion has a rectangular upper surface which is a piezoelectric body surface parallel to the polarization direction P. The shape of the upper surface of the piezoelectric vibrating portion is within a range of ± 10% around a value satisfying the above-described expression (2) when the length of the short side is a and the length of the long side is b. Have been selected as such.
Therefore, by applying an AC voltage from the first and second resonance electrodes 373 and 374, the piezoelectric vibrating portion is moved to the position shown in FIG.
5 resonates in the slip mode in the same manner as the piezoelectric resonator 311,
Moreover, the resonance energy is effectively confined in the piezoelectric vibrating portion. The piezoelectric plate portions on the sides of the grooves 375 and 376 constitute the support portion of the present invention, and the piezoelectric plate portions outside the grooves 375 and 376 constitute the holding portion of the present invention. Further, on the upper surface of the holding portion, extraction electrodes 377 and 3 are provided so as to be electrically connected to the first and second resonance electrodes, respectively.
78 are formed.

FIG. 24 is a plan view showing still another example of the energy trap type piezoelectric resonator of the second type.
In the piezoelectric resonator 381, the dynamic vibration absorbing portions 391 to 394 are formed by forming the grooves 383 to 386 on one side surface and forming the grooves 387 to 390 on the other side surface.
Further, the portion of the piezoelectric substrate between the grooves 384 and 385 constitutes the piezoelectric vibrating portion 395 in the present invention. Also, the groove 38
Outside of the holding portions 396 and 397, respectively.
Are formed. In addition, the support portion of the present invention is
Piezoelectric substrate portion and groove 38 sandwiched between 4,388
The piezoelectric substrate portion is sandwiched between 5,389. The piezoelectric substrate portion between the grooves 383 and 387 and the groove 38
The thin piezoelectric substrate portion between 6,390 constitutes the connecting portion.

The piezoelectric vibrating section 395 is polarized so as to extend along the direction of arrow P shown in the figure, that is, along the length of the piezoelectric substrate 382. On the other hand, the resonance electrodes 398 and 399 are formed on the upper surface of the piezoelectric substrate 382 in parallel with the polarization direction P.
Also, the upper surface of the piezoelectric vibrating section 395 has a rectangular shape,
Assuming that the length of the short side of the upper surface is a and the length of the long side is b, the ratio b / a is within a range of ± 10% around a value that satisfies the expression (2). I have.

Therefore, by applying an AC voltage from the resonance electrodes 398 and 399, the piezoelectric vibrating section 395 resonates in a slip mode, and the resonance energy is effectively confined in the piezoelectric vibrating section 395. Further, the dynamic vibration absorber 391-
394 suppresses the slight vibration that has leaked by the dynamic vibration absorption phenomenon. Therefore, in the piezoelectric resonator 381, the vibration energy is reliably confined to the portion where the dynamic vibration absorbing portions 391 to 394 are provided. The holding parts 396, 3
On 97, extraction electrodes 400 and 401 are formed.

FIG. 25 shows the piezoelectric resonator 38 shown in FIG.
This is a modification of the first embodiment. The difference from the piezoelectric resonator 381 is that, in the piezoelectric resonator 411, the piezoelectric vibrating portion 395 is polarized in the direction indicated by arrow P, that is, parallel to the width direction of the piezoelectric substrate 382.
399 are formed to extend in the width direction.

FIG. 26 shows the piezoelectric resonator 38 shown in FIG.
It is a perspective view which shows the further another modification of 1. In the piezoelectric resonator 421, the piezoelectric vibrating portion 395 is polarized in a direction indicated by an arrow P, that is, parallel to the length direction of the piezoelectric substrate 382. The difference from the piezoelectric resonator 381 is the position where the electrodes are formed.

That is, in the piezoelectric resonator 421, the resonance electrodes 398 and 399 are formed on both sides of the piezoelectric substrate 382 in the piezoelectric vibrating section 395. In the piezoelectric resonator 421, the extraction electrodes 400 and 401 are formed on the side surfaces of the piezoelectric substrate 382 in the holding portions 396 and 397, respectively. In addition, the extraction electrodes 400 and 4
01 and a connection conductive portion electrically connected to the resonance electrodes 398 and 399 are also formed along the side surface of the piezoelectric substrate 382.

As is apparent from the piezoelectric resonator 421, the resonance electrodes of the second type of piezoelectric resonator are formed not only on the upper and lower surfaces of the piezoelectric plate constituting the piezoelectric vibrating portion but also on the side surfaces. Is also good. Further, for example, in the piezoelectric resonator 381 shown in FIG.
May be formed on the lower surface of the piezoelectric substrate 382, or one of the resonance electrodes 39 in the piezoelectric resonator 421.
8 or 399 may be formed on one main surface side of the piezoelectric substrate 382.

Further, also in the second type of piezoelectric resonator, the piezoelectric vibrating portion, the supporting portion, the holding portion, and the dynamic vibration absorbing portion provided as necessary, are obtained by machining a single piezoelectric substrate. They may be configured, or they may be configured by separate members.

For example, as shown in FIG. 27, by joining insulating plates 432 and 433 having the same thickness to a rectangular piezoelectric plate 431 for forming a piezoelectric vibrating section,
34 may be formed. The substrate 434 can be used to form the second type of piezoelectric resonator. In addition, in the substrate 434 shown in FIG.
33, the dynamic vibration absorbing portions 435 and 436 and the holding portions 437 and 4
Although 38 is integrally formed, each of these parts may be formed of a separate member.

Further, as shown in FIG.
Outside the portions 35 and 436, the substrate portions 439 and 44 having the same width are provided.
0 may be formed. In this case, the substrate portion 439,
The reference numeral 440 also serves as a connecting portion and a holding portion.

First Embodiment FIG. 29 is an exploded perspective view of a ladder-type filter according to the first embodiment, and FIG. 30 is a perspective view showing the appearance of the ladder-type filter.

The ladder type filter 20 includes a case substrate 21, a first resonance plate 22, a separating spacer 23, a second resonance plate 24, and a case substrate 25 shown in FIG.
Are laminated.

The first resonance plate 22 is composed of piezoelectric resonators 26 and 27 with a built-in dynamic vibration absorbing portion using a sliding vibration mode.
And a piezoelectric resonator 28 with a built-in dynamic vibration absorbing portion using a width expansion mode, and are integrated, and furthermore, spacer plates 29 and 30 having the same thickness as the piezoelectric resonators 26 to 28 with a built-in dynamic vibration absorbing portion are bonded to the outside. It has a structure joined using an agent. The spacer plates 29 and 30 are made of an insulating material having an appropriate degree of strength, such as insulating ceramics such as alumina or a synthetic resin, and do not hinder the vibration of the vibrating portions of the piezoelectric resonators 26 and 27. Notch 29
a and 30a.

The piezoelectric resonator 26 with a built-in dynamic vibration absorber is shown in FIG.
As shown in (a), the piezoelectric ceramic plate 26a is formed using an elongated rectangular plate-shaped piezoelectric ceramic plate 26a uniformly polarized in a direction indicated by an arrow P. On one side surface of the piezoelectric ceramic plate 26a, a resonance electrode 26b is formed from one end of the piezoelectric ceramic plate 26a toward the other end. The end of the resonance electrode 26b ends at a portion reaching the concave portion 26c formed by notching the side surface. In addition, recess 2
A concave portion 26d is formed at a predetermined distance from 6c,
Thereby, a dynamic vibration absorbing portion 26e is formed between the concave portions 26c and 26d.

Similarly, a resonance electrode 26f is formed on the other side surface of the piezoelectric ceramic plate 26a so as to extend from the other end of the piezoelectric ceramic plate 26a to the one end. By forming two concave portions 26g and 26h in the same manner as the side on which the resonance electrode 26b is formed,
The dynamic vibration absorbing portion 26i is configured.

In the piezoelectric resonator 26 of the second type, the portion where the resonance electrode 26b and the resonance electrode 26f overlap constitutes a piezoelectric vibrating portion, and the dimensional ratio b / a of the piezoelectric vibrating portion is as described above. ± centered on the value that satisfies equation (2)
It is within the range of 10%. That is, it is configured similarly to the piezoelectric resonator 371 shown in FIG. A portion between the piezoelectric vibrating portion and the dynamic vibration absorbing portions 26e and 26i constitutes a supporting portion, and a portion of the piezoelectric ceramic plate at an outer end than a portion where the concave portions 26d and 26h are formed constitutes a holding portion. A relatively narrow piezoelectric ceramic portion between the portion and the dynamic vibration absorbing portions 26e and 26i constitutes a connecting portion.

In the piezoelectric resonator 26 with a built-in dynamic vibration absorbing section, by applying an AC voltage from the resonance electrodes 26b and 26f, the region where the resonance electrodes 26b and 26f overlap resonates in a slip vibration mode, and operates as a piezoelectric resonator. I do. In addition, since the resonance section is formed to have the specific dimensional ratio, the resonance energy is effectively confined.

Further, even if the vibration generated in the region where the resonance electrodes 26b and 26f overlap is leaked, the vibration electrodes 26b and 26f are reliably confined to the portions up to the dynamic vibration absorbing portions 26e and 26i. That is, even if the resonance of the slip vibration mode leaks outside from the resonance portion, the dynamic vibration absorbing portion 26
e, 26i resonate and are attenuated by the dynamic vibration absorption phenomenon. Therefore, almost no vibration is transmitted to the piezoelectric ceramic plate portion outside the dynamic vibration absorbing portions 26e and 26i. Therefore,
In the piezoelectric resonator 26, by connecting the piezoelectric ceramic plate portion outside the dynamic vibration absorbing portions 26e and 26i to another member, the piezoelectric resonator 26 can be mechanically held without hindering the resonance of the resonance portion. It is possible.

Returning to FIG. 29, the piezoelectric resonator 28 with a built-in dynamic vibration absorber used for the first resonance plate 22 is
This will be described with reference to FIG. The dynamic vibration absorbing section built-in type piezoelectric resonator 28 is the above-described first and fourth types of piezoelectric resonators, and is configured using a piezoelectric ceramic plate 28a having a planar shape shown in FIG. In the piezoelectric ceramic plate 28a, a piezoelectric vibrating portion 28b having a rectangular planar shape is formed at the center of the piezoelectric ceramic plate. In the piezoelectric vibrating portion 28b, a polarization process is performed in a direction indicated by an arrow P, and a resonance electrode 28c is formed on both main surfaces (the resonance electrode on the lower surface is not shown).

The vertical / horizontal dimension ratio b / a of the piezoelectric vibrating portion 28b is selected so as to fall within a range of ± 10% around a value satisfying the above-mentioned expression (1). By applying an AC voltage from the resonance electrodes 28c of the both main surfaces of the piezoelectric vibrating portion 28b, the piezoelectric vibrating portion 28b is resonated in a width expansion mode, the b / a ratio is within the range specified above, the piezoelectric vibrating portion The resonance energy is effectively confined.

On the other hand, in the center of the side surface of the piezoelectric vibrating portion 28b facing each other, elongated rod-shaped support portions 28d and 28e are provided.
Are connected to each other, and dynamic vibration absorbing portions 28f and 28g are formed at outer ends of the supporting portions 28d and 28e, respectively. The dynamic vibration absorbing portions 28f and 28g are configured to vibrate in a bending mode, and are configured to resonate by the vibration transmitted from the piezoelectric vibrating portion 28b. Therefore, even if the resonance energy in the piezoelectric vibrating portion 28b leaks, it is reliably confined to the portions up to the dynamic vibration absorbing portions 28f and 28g.

The connecting portions 28h and 28i are connected to the outside of the dynamic vibration absorbing portions 28f and 28g, and the holding portions 28j and 28k are connected to the outer ends of the connecting portions 28h and 28i. The holding portions 28j and 28k are
Is provided as a part for connecting to other members or mechanically holding the same, and has a relatively large area as shown in the figure.

The piezoelectric resonators 26 and 28 with a built-in dynamic vibration absorber shown in FIGS. 31 (a) and 31 (b) are formed by machining a single piezoelectric ceramic plate as described above. Alternatively, each part may be formed separately and connected to each other by an adhesive or the like. For example, instead of the piezoelectric ceramic plate 28a shown in FIG.
The supporting portions 28d and 28e and the dynamic vibration absorbing portions 28f and 28 are provided on the sides of the rectangular piezoelectric ceramic plate forming the piezoelectric vibrating portion.
g, the members constituting the connecting portions 28h and 28i and the holding portions 28j and 28k may be integrated by bonding with an adhesive or the like. In a piezoelectric resonator with a built-in dynamic vibration absorber used in the following embodiments, the piezoelectric ceramic plate for forming each piezoelectric resonator is the same as that of the present embodiment. It should be pointed out that this may be formed by machining or by connecting a plurality of members.

The resonance electrode 28c is connected to the connection conductive portion 28.
electrode 28m formed on the upper surface of the holding portion 28k via
Is electrically connected to Similarly, the resonance electrode formed on the lower surface of the resonance portion 28b is also electrically connected to the electrode formed on the lower surface of the holding portion 28j via the connection conductive portion.

Returning to FIG. 29, the piezoelectric resonator 27 with a built-in dynamic vibration absorber having the same structure as the piezoelectric resonator 26 with a built-in dynamic vibration absorber, and the piezoelectric resonators 26 and 28 with a built-in dynamic vibration absorber are mutually connected. The first resonance plate 22 is integrated by bonding the side surfaces of the holding portion with an insulating adhesive, and further joining the first and second spacer plates 29 and 30 to the side. Is configured.

In the resonance plate 22, on the upper surface side,
An electrode 22a for electrically connecting the piezoelectric resonators 26 to 28 so as to constitute a ladder-type filter as described later.
To 22d are formed. The electrode 22a is electrically connected to the resonance electrode 26f of the piezoelectric resonator 26 (see FIG. 31A). Similarly, the electrode 22c is electrically connected to the resonance electrode 26b, and the electrodes 22b and 22d are each electrically connected to one resonance electrode formed on the side surface of the piezoelectric resonator 27. Further, in the piezoelectric resonator 28, an electrode 28m connected to one of the resonance electrodes 28c is formed so as to reach the edge of the resonance plate 22 as shown in the drawing, and is electrically connected to the resonance electrode on the lower surface side as well. The electrode to be connected is also formed on the lower surface of the resonance plate 22 so as to reach the opposite edge.

In the second resonance plate 24, the same as the piezoelectric resonator 28 with a built-in dynamic vibration absorbing portion is provided on both sides of the piezoelectric resonator 31 with a built-in dynamic vibration absorbing portion utilizing the sliding vibration mode having the same structure as the piezoelectric resonator 26. The piezoelectric resonators 32 and 33 with a built-in dynamic vibration absorbing portion using the width expansion mode are bonded. Further, the first and second spacer plates 34 and 35 made of an insulating material having an appropriate degree of strength, such as insulating ceramics or synthetic resin, having the same thickness as those of the piezoelectric resonators 31 to 33 are used as piezoelectric members. Resonator 32,
33 is adhered to the side. Spacer plates 34, 35
Has cutouts 34a and 35a in a substantially U-shape at the edges on the side of the piezoelectric resonators 32 and 33, as shown in FIG. Notch 34a,
The reference numeral 35a is provided to secure a space for preventing the vibration of the resonance portions and the dynamic resonance portions of the piezoelectric resonators 32 and 33.

The piezoelectric resonator 31 and the piezoelectric resonator 3
The structures of the piezoelectric resonators 2 and 33 are the same as those of the piezoelectric resonator 26 and the piezoelectric resonator 28 described above, and a detailed description thereof will be omitted.

In the second resonance plate 24, electrodes 24a and 24b are formed on the upper surface so as to reach different edges. The electrodes 24a and 24b are electrically connected to one of the resonance electrodes formed on both side surfaces of the piezoelectric resonator 31, respectively. In the piezoelectric resonators 32 and 33,
The electrodes 32c and 33d on the holding portion electrically connected to the resonance electrodes 32a and 33a formed on the upper surface are formed so as to reach different edges of the resonance plate 24. Also,
Resonance electrodes formed on the lower surfaces of the resonating portions of the piezoelectric resonators 32 and 33 are electrically connected to electrodes reaching the opposite edge on the lower surfaces.

The case substrates 21 and 25 have concave portions 21a and 25a on the lower surface and the upper surface, respectively. Recesses 21a,
The reference numeral 25a is provided so as not to hinder the vibration of the resonance part and the dynamic vibration absorbing part of the adjacent piezoelectric resonators when they are stacked. Also, in the separation spacer 23, the concave portion 23a is formed on the upper surface.
Although not clear in FIG. 29, a concave portion having the same shape as the concave portion 23a is also formed on the lower surface side. These recesses are provided so as not to hinder the vibration of the resonance part and the dynamic vibration absorbing part of the piezoelectric resonators arranged vertically.

However, the recesses 21a, 23a,
Instead of providing the 25a, a flat case substrate 21, a separating spacer 23, and the case substrate 25 may be used. In that case, a rectangular frame-shaped spacer having a thickness corresponding to the depth of the concave portions 21a, 23a, 25a is interposed between the piezoelectric vibrating portion and the dynamic vibration absorbing portion so as not to hinder the vibration. A similar space needs to be formed by applying the agent in a rectangular frame shape.

The case substrates 21 and 25 and the separating spacer 23 can be made of an insulating material having a certain strength, for example, an insulating ceramic such as alumina or a synthetic resin.

In this embodiment, the case substrate 21 described above is used.
The first resonance plate 22, the separation spacers 23, the second resonance plate 24, and the case substrate 25 are laminated and bonded with an insulating adhesive, thereby being integrated as a ladder-type filter having a laminated structure. This will be described with reference to FIG.

As is clear from FIG. 30, the ladder-type filter 20 of this embodiment has a structure in which a plurality of rectangular plate-like members are laminated, and the terminal electrodes 20a to 20l extend from the side surface to the upper surface and the lower surface. Are formed. Terminal electrode 20
a to 201 can be formed by applying and baking a conductive paste, or by vapor deposition, plating, sputtering, or the like. Further, as shown in FIG. 29, the electrode 21 is placed on the upper surface of the case substrate 21 in advance.
b, a plurality of terminal electrode portions are similarly formed on the lower surface of the case substrate 25, and thereafter, an electrode material is applied to the side surface of the laminate as shown in FIG. By doing so, the terminal electrodes 20a to 20l extending from the side surface to the upper surface and the lower surface may be formed.

In the ladder-type filter obtained as described above, as shown in FIG. 32, the terminal electrodes 20a to 20l
Are connected, and the terminal electrode 20a is used as an input terminal.
k, 20j as output terminals, and terminal electrodes 201, 20f, 2
By connecting Ob to the ground potential, it is possible to operate as a ladder-type filter shown in the circuit diagram of FIG.

In the ladder-type filter 20 of the present embodiment, a series resonator and a parallel resonator are constituted by using the piezoelectric resonators 26 to 28 and 31 to 33 with built-in dynamic vibration absorbers using the slip vibration mode and the width vibration mode. Have been. Therefore, the pass band width can be easily expanded as compared with a ladder type filter using a tuning fork type piezoelectric resonator.

In addition, in each of the resonators with a built-in dynamic vibration absorbing portion, the vibration energy is effectively confined in a portion up to the dynamic vibration absorbing portion. So that they can be easily connected and integrated.

Second Embodiment FIG. 34 is an exploded perspective view for explaining a ladder-type filter of a second embodiment, and FIG. 35 is a perspective view showing an appearance of the ladder-type filter of the second embodiment. It is. The ladder filter 40 includes, in order from the top, a case substrate 41, a cavity forming spacer 42, a first resonance plate 43, a cavity forming spacer 44, a second resonance plate 45, a cavity forming spacer 46, and a third resonance. It has a structure in which a plate 47, a cavity forming spacer 48, a fourth resonance plate 49, a cavity forming spacer 50, and a case substrate 51 are sequentially laminated.

The case substrates 41 and 51 are made of the same material as the case substrates 21 and 25 used in the first embodiment. However, the case substrates 41 and 51 are formed of plate-like members, and the case substrates 21 and 51 of the first embodiment.
The concave portions 21a and 25a in 25 are not formed.
Therefore, the spacer 42 is inserted in order to form a space for preventing the vibration of the vibration part of the first resonance plate 43 disposed below the case substrate 41. Similarly, a cavity forming spacer 50 is used on the upper surface side of the case substrate 51 in order to secure a space for preventing the vibration of the vibrating portion of the fourth resonance plate 49.

The cavity forming spacers 42 and 50 are formed of thin rectangular frame members as shown in the figure.
For example, it can be made of a synthetic resin or other appropriate insulating material. The other cavity forming spacers 44, 4
6 and 48 can be made of the same material as that of the cavity forming spacers 42 and 50.

The first resonance plate 43 has a piezoelectric resonator 52 with a built-in dynamic vibration absorber that vibrates in the length vibration mode.
As shown in the plan view of FIG. 36A, the piezoelectric resonator 52 is formed of a piezoelectric ceramic plate, and has a piezoelectric vibrating portion 52a that vibrates in a length vibration mode at the center. The piezoelectric vibrating portion 52a has an elongated rectangular plate shape, and is polarized so that the polarization axis is along the length direction. The piezoelectric vibrating part 52a
Are supported by the supporting portions 52b and 52c. At the outer ends of the support portions 52b and 52c, dynamic vibration absorbing portions 52d and 52e configured to resonate in a bending mode are formed. The dynamic vibration absorbing portions 52d and 52e are provided with a piezoelectric vibration portion 52a.
Are resonated by the vibrations leaked when they are resonated, and the dimensions thereof are determined so as to prevent the vibration energy from leaking outside the dynamic vibration absorbing portions 52d and 52e by the dynamic vibration absorbing phenomenon.

Outside the dynamic vibration absorbing portions 52d and 52e, connecting portions 52f and 52g having a relatively small width are connected.
And holding portions 52h, 5 having a relatively large area outside thereof.
2i are connected.

The spacers 53, 54 having the same thickness as the piezoelectric resonator 52 with a built-in dynamic vibration absorbing portion are provided on the holding portions 52h, 52i.
Are adhered and integrated to form a first resonance plate 43. In this case, the piezoelectric vibrating section 52
a of the holding portions 52h and 52i or the spacers 53 and 52
54 shapes have been selected.

In the piezoelectric vibrating section 52a, the piezoelectric vibrating section 5
Resonance electrodes 52j and 52k for exciting 2a are formed on the upper surface, and the resonance electrodes 52j and 52k are electrically connected to the electrodes 52m and 52n formed on the holding portions 52h and 52i via connection conductive portions. It is connected to the.

On the other hand, the second resonance plate 45 has a structure in which spacers 56 and 57 are joined to the side of the piezoelectric resonator 55 with a built-in dynamic vibration absorber. The spacers 56 and 57 are configured similarly to the spacers 53 and 54 described above.

As shown in the plan view of FIG. 36 (b), the piezoelectric resonator 55 has an elongated rectangular plate-shaped piezoelectric vibrating portion 55 at the center.
a. A support portion 55 is provided beside the piezoelectric vibrating portion 55a.
b and 55c are connected to each other, and dynamic vibration absorbing portions 55d and 55e are formed at outer ends of the support portions 55b and 55c. Has a structure in which holding portions 55h and 55i having a large area are formed. Therefore, the planar shape as a whole is the same as that of the piezoelectric resonator 52 with a built-in dynamic vibration absorber.

The difference is that a resonance electrode 55j is formed on the entire upper surface of the piezoelectric vibrating portion 55a, and a resonance electrode (not shown) is similarly formed on the entire lower surface.
In addition, the piezoelectric vibrating portion 55a is characterized in that the piezoelectric ceramic plate is uniformly polarized in the thickness direction. That is, the piezoelectric vibrating portion 55a is also configured to vibrate in the length mode.

The one resonance electrode 55j of the piezoelectric vibrating portion 55a is electrically connected to an electrode 55k formed on the holding portion 55i via a connection conductive portion, and the resonance electrode formed on the lower surface is , Are electrically connected to electrodes formed on the lower surface of the holding portion 55h via the connection conductive portion.

Returning to FIG. 34, the third resonance plate 47
Is different from the first resonance plate 43 only in how the electrodes are drawn out to the holding portion. Therefore, the dynamic vibration absorbing portion built-in piezoelectric resonator 58 and the spacer 59, which constitute the third resonance plate 47, The description of 60 will be omitted by using the description given for the first resonance plate 43 above.

Similarly, the fourth resonance plate 49 is different from the second resonance plate 45 only in the way of drawing out the electrode to the holding portion. The electrode 61c on the holding portion 61d that is electrically connected to the resonance electrode 61b formed on the upper surface of the piezoelectric vibrating portion 61a of the resonator 61 is different from the holding portion 61d.
Is formed in the central part of. On the other hand, the piezoelectric vibrating portion 61a
The resonance electrode (not shown) formed on the entire lower surface of
It is electrically connected to an electrode formed at the lower end of the holding portion 61e.

The purpose of making the extraction electrodes of the third and fourth resonance plates different from those of the first and second resonance plates is as follows. That is, the electrodes 60m and 61m in FIG. 34 are conducted by the external electrode 40a, and the electrodes 52n, 55k, and 60n are conducted by the external electrode 40d.
Thus, a two-stage ladder filter shown in FIG. 37 is configured. Although the electrode 40d is a dummy electrode, it has the function as described above. In addition, the external electrode 4
0f is a pure dummy electrode.

In the second embodiment, as in the first embodiment, each member is laminated, and external electrodes are formed so as to extend from the side surface to the upper surface and the lower surface. The ladder-type filter 40 is completed. In FIG. 35, reference numerals 40a to 40f denote external electrodes. In FIG. 35, the spacers 42 and 4 having relatively small thicknesses are shown.
Illustrations of 4, 46 and 48 are omitted.

Therefore, the external electrode 40c is connected to the input terminal, the external electrode 40a is connected to the output terminal, and the external electrodes 40b and 40e are connected to the ground potential, thereby operating as a two-stage ladder filter as shown in FIG. Can be.

Third Embodiment FIG. 38 is an exploded perspective view showing a one-stage ladder-type filter according to a third embodiment, and FIG. 39 is a perspective view showing its appearance.

In the ladder filter 110 of this embodiment,
Case substrate 111, resonance plate 112, cavity forming spacer 113, resonance plate 114, and case substrate 11
5 are stacked.

A recess 115 a is formed on the upper surface of the case substrate 115.
However, a similar concave portion is formed on the lower surface of the case substrate 111, and a space for preventing the vibration of the vibrating portion of the laminated resonance plate is secured.
Further, by interposing the cavity forming spacer 113 therebetween, a space is formed so as not to hinder the vibration of the vibration portions of the resonance plates 112 and 114.

The details of the case substrates 111 and 115 and the cavity-forming spacer 113 are the same as those of the case substrate and the cavity-forming spacer used in the first embodiment, and a detailed description thereof will be omitted. .

The resonance plate 112 is provided with spacers 1 on both sides of the piezoelectric resonator 26 with a built-in dynamic vibration absorber shown in FIG.
16, 117 are bonded. Spacer 1
Notches 116 and 117 are provided on the side surface on the piezoelectric resonator 26 side.
a, 117a so that the vibration of the vibrating portion of the piezoelectric resonator 26 is not hindered.

On the other hand, the resonance plate 114 is the same as the piezoelectric resonator 28 shown in FIG. 31B, except that the positions of the electrodes where the resonance electrodes are drawn out are slightly different. Spacers 118, 119 on the sides of
Are bonded together. Spacer 1
18, 119 have cutouts 118a, 119a on the piezoelectric resonator 28 side, like the spacers 116, 117.

Although not clearly shown in FIG. 38, in the piezoelectric resonator 28, a resonance electrode is also formed on the lower surface of the resonance part 28b, and the electrode electrically connected to the resonance electrode is a resonance plate. 114 are formed to reach the edge 114a side.

In the ladder filter 110 of this embodiment,
Each of the above members is laminated, and as shown in FIG.
It is completed by forming 0a, 110b, 110c on the side surface. That is, the external electrode 110a is connected to the ground potential, the external electrode 110b is connected to the input terminal, and the external electrode 110c is
Is used as the output end, a one-stage ladder-type filter can be configured as shown in FIG. By laminating two or more resonance plates 112 and 114, a ladder filter having two or more stages can be easily formed.

Fourth Embodiment FIG. 41 is an exploded perspective view for explaining a ladder type filter according to a fourth embodiment, and FIG. 42 is a perspective view showing an appearance of the ladder type filter.

The ladder-type filter 130 is provided on the case substrate 1.
31, cavity forming spacer 132, first resonance plate 133, cavity forming spacer 134, second resonance plate 135, cavity forming spacer 136 and case substrate 1
37 are stacked.

The case substrates 131 and 137 are made of flat insulating ceramics or synthetic resin or the like. The cavity forming spacers 132, 134 and 136 are
The configuration is the same as that of the cavity forming spacer used in the second embodiment.

The first resonance plate 133 is composed of a piezoelectric resonator 138, 13 with a built-in dynamic vibration absorbing portion using a width expansion mode.
9 are integrated by bonding their holding parts together, and further have a structure in which spacers 140 and 141 are attached to the outside.

The piezoelectric resonator 138 has the same configuration as the piezoelectric resonator 28 with a built-in dynamic vibration absorbing portion using the width expansion mode used in the first embodiment. Also, the piezoelectric resonator 139 with a built-in dynamic vibration absorber using the width expansion mode, but using the longitudinal effect, is a piezoelectric ceramic plate having the same planar shape as the piezoelectric resonator 138, as shown in the right side of FIG. The resonance electrodes 139a and 139b are formed on a pair of opposite edges on the lower surface of the resonance section. The polarization direction is indicated by an arrow in the figure.
Therefore, by applying an AC voltage between the resonance electrodes 139a and 139b, the resonator operates as a widening mode resonator utilizing the piezoelectric longitudinal effect. Note that the resonance electrodes 139a, 139a, 1
39b are respectively drawn to different opposite edges of the resonance plate 133.

[0157] The second resonance plate 135, like the first resonant plate 133, a dynamic vibration absorbing portion embedded piezoelectric resonator 142 of transverse effect using width expansion mode, the dynamic vibration reducer unit embedded utilizing a longitudinal effect By attaching the holding portions of the piezoelectric resonator 143 to each other, the spacers 1
44 and 145 are attached to each other. However, in the second resonance plate 135, in the dynamic vibration absorbing section built-in type piezoelectric resonator 143 utilizing the longitudinal effect,
The pair of resonance electrodes 143a and 143b
5 is formed on the upper surface side.

The ladder-type filter 130 of this embodiment is obtained by stacking the above-described members and forming external electrodes 130a to 130f shown in FIG. 42 on both end surfaces of the obtained stack.

43. That is, the external electrode 130c is used as an input terminal, the external electrodes 130a and 130d are commonly connected and used as an output terminal, the external electrodes 130e and 130f are commonly connected, and the external electrode 130b is connected to the ground potential. The two-stage ladder filter shown in FIG.

Fifth Embodiment The structure of a ladder filter 150 according to a fifth embodiment is as follows.
FIG. 44 is an exploded perspective view, and FIG. 45 is an external perspective view.

This embodiment corresponds to a modification of the ladder filter of the fourth embodiment. Therefore, only different parts will be described. First resonance plate 151
Has a structure in which the piezoelectric resonators 153 and 154 with a built-in dynamic vibration absorbing section in the width expansion mode using the piezoelectric longitudinal effect are integrated by bonding their holding sections. The structure of the piezoelectric resonators 153 and 154 is the same as that of the piezoelectric resonator 143 used in the fourth embodiment.

On the other hand, in the second resonance plate 152, the piezoelectric resonators 155 and 156 with a built-in dynamic vibration absorbing portion in the width expansion mode using the piezoelectric transverse effect are integrated by bonding their holding portions.

The piezoelectric resonators 155 and 156 have the same configuration as the piezoelectric resonator 138 used in the fourth embodiment. In the first resonance plate 151, electrodes 151a and 151b are formed on the upper surface side along one edge, and the electrodes 151a and 151b are electrically connected to one of the piezoelectric resonators 153 and 154, respectively. It is connected to the. On the other hand, an electrode 151c is formed along the other edge of the resonance plate 151, and the electrode 151c
Are electrically connected to the other resonance electrodes of the piezoelectric resonators 153 and 154, respectively.

In the resonance plate 152, the resonance electrodes 155a and 156a of the piezoelectric resonators 155 and 156 are provided.
The electrode 152a electrically connected to the
2 is formed along one edge. On the other hand, on the lower surface of the resonance plate 152, the piezoelectric resonator 155,
The electrode 1 electrically connected to the resonance electrode on the lower surface side of 156
52b and 152c are formed along the other edge of the resonance plate 152, respectively.

[0165] Reference numerals 157 and 158 denote case substrates.
Numerals 59a to 159c denote cavity forming spacers. The ladder-type filter 150 of the fifth embodiment is obtained by forming the external electrodes 150a to 150f on the laminate obtained by laminating the above members as shown in FIG.

The ladder-type filter 150 can be operated as a two-stage ladder-type filter similarly to the fourth embodiment by connecting external electrodes as in the fourth embodiment.

Sixth Embodiment FIG. 46 is an exploded perspective view for explaining a ladder filter according to a sixth embodiment, and FIG. 47 is a perspective view showing the appearance of the ladder filter.

The ladder-type filter 160 of this embodiment has the same configuration as that of the fourth embodiment except that the structures of the first and second resonance plates are different. Referring to FIG. 46, the first resonant plate 161 includes a dynamic vibration reducer unit built piezoelectric resonator 162 utilizing a shear mode, the dynamic vibration reducer unit built piezoelectric resonator 163 using the width expansion <br/> mode Are integrated by bonding their holding parts to each other. Spacers 1 are provided outside the piezoelectric resonators 162 and 163.
64 and 165 are stuck together.

The piezoelectric resonator 162 is a piezoelectric resonator 26 using the slip mode used in the first embodiment (FIG. 17).
(See (a)). A resonance electrode formed on one side surface of the piezoelectric resonator 162 is connected to an electrode 161 formed along one edge of the resonance plate 161.
a. On the other hand, the resonance electrode formed on the other side surface is electrically connected to an electrode 161b formed along the other edge of the resonance plate 161.

The piezoelectric resonator 163 with a built-in dynamic vibration absorbing portion using the width expansion mode has the same configuration as the piezoelectric resonator 138 used in the fourth embodiment. The resonance electrode 163a on the upper surface of the piezoelectric resonator 163 is electrically connected to the electrode 161c. The electrode 161c is
It is formed along the same edge as.

On the other hand, as shown by the broken line on the right side of FIG.
On the lower surface side of the resonance plate 161, the piezoelectric resonator 1
The resonance electrode 163 b formed on the lower surface of the electrode 63 is formed along the one edge of the resonance plate 161.
1d.

The second resonance plate 166 corresponds to a structure in which the first resonance plate 161 is inverted. That is, the piezoelectric resonator 167 with a built-in dynamic vibration absorbing unit using the sliding mode and the piezoelectric resonator 168 with a built-in dynamic vibration absorbing unit using the width expansion mode are integrated by bonding the holding parts together,
It has a structure in which spacers 169a and 169b are attached to the outside.

Since the first resonance plate 161 is equivalent to an inverted one, the electrodes formed on both main surfaces are upside down with respect to the first resonance plate 161. Each of the above members was laminated, and the resulting laminate was provided with terminal electrodes 160a.
By forming 160f, a ladder filter 160 shown in FIG. 47 is obtained. Also in this embodiment, as in the fourth embodiment, the external electrodes 160a and 160d are used as output terminals, the external electrode 160c is used as an input terminal, and
60b is connected to the ground potential, and the external electrodes 160e, 160
By connecting f in common, it is possible to operate as a two-stage ladder-type filter.

Seventh Embodiment FIG. 48 is an exploded perspective view of a ladder filter according to a seventh embodiment, and FIG. 49 is a perspective view showing an appearance of the ladder filter.

In this embodiment, the first case substrate 171,
The resonance plates 172 to 175 and the case substrate 176 are stacked. Here, in order not to hinder the vibration of the resonator,
A vibration space is secured by the resonance plates 172 to 175 applying and bonding a frame-like adhesive thereto.

The resonance plate 172 is formed by joining first and second spacer plates 178 and 179 to the side of the first type energy trap type piezoelectric resonator 177. The piezoelectric resonator 177 has a structure in which holding parts 182 and 183 are connected to a rectangular plate-shaped piezoelectric vibrating part 181 via a support part. In the piezoelectric vibrating section 181,
A first resonance electrode 180a is formed on the upper surface, and a second resonance electrode 180b is formed on the lower surface. Also in the present embodiment, when the length of the short side is a and the length of the long side is b, the upper surface of the piezoelectric vibrating part 181 has a value of ± 10% around the value satisfying the expression (1). The ratio b / a is determined so as to be within the range. Therefore, the vibration energy is effectively confined in the piezoelectric vibration part 181.

The resonance plate 175 has substantially the same configuration as the resonance plate 172. However, the positions of the extraction electrodes that are electrically connected to the resonance electrodes 180a and 180b and that are formed on the holding portions 182 and 183 are different from those of the resonance plate 172.

In the resonance plates 172 and 175, the first and second resonance electrodes 180a and 180b are formed to have an area considerably smaller than the main surface of the piezoelectric vibrating portion 181. Therefore, the capacitance between the electrodes 180a and 180b is relatively small.

On the other hand, in the resonance plate 173, an energy trapping type piezoelectric resonator 185 using a first type of width expansion mode is used, and first and second piezoelectric resonators 185 are provided beside the piezoelectric resonator 185. Spacer plates 186, 18
7 are joined. The piezoelectric resonator 185 has the same configuration as the piezoelectric resonator 177 except for the resonance electrode.
Therefore, the same portions are denoted by the same reference numerals and the description thereof will be omitted. In the piezoelectric resonator 185, the first and second resonance electrodes 188a and 188b are formed in a rectangular shape so as not to reach the outer peripheral edge on the upper and lower surfaces of the piezoelectric vibrating portion 181, but to have a considerably large area. I have. Therefore, the capacitance between the resonance electrodes 188a and 188b is equal to the capacitance of the resonance electrode 18 in the piezoelectric resonator 177.
The capacitance is considerably larger than the capacitance between 0a and 180b.

Also in the piezoelectric resonator 185, since the piezoelectric vibrating portion 181 is provided so as to constitute the first type energy trap type piezoelectric resonator, the vibration energy is effectively confined in the piezoelectric vibrating portion 181. Can be

In the ladder type filter of this embodiment, the case substrates 171 and 176 and the resonance plates 172 to 172 are used.
5 are laminated and a predetermined external electrode is formed.

That is, as shown in FIG.
In the ladder filter 170, the external electrodes 189a to 189c
Are on one side of the obtained laminate, 189d to 189f
Is formed on the other side surface. By using the external electrode 189a as an output terminal, connecting the external electrodes 189b and 189e to the ground potential, and using the external electrode 189c as an input terminal, a two-stage ladder filter is formed. In this case, the above-described piezoelectric resonators 177, 177 replace the series resonators with the piezoelectric resonators 185, 185 having a relatively large capacity.
Constitute a parallel resonator. The electrode 189d has a function of short-circuiting the terminal electrodes A, B, and C, or the external electrode 1
Reference numerals 89d and 189f denote dummy external electrodes which are not used for connecting an external circuit when operating as a ladder-type filter.

Eighth Embodiment FIG. 50 is an exploded perspective view for explaining a ladder filter according to an eighth embodiment. In the ladder filter of the present embodiment, a plurality of piezoelectric resonators are stacked in a space defined by the base substrate 191 and the cap member 192. The base substrate 191 is made of an appropriate insulating material such as an insulating ceramic such as alumina or a synthetic resin. On the base substrate 191, connection conductive portions 191a to 191e are provided.
It is dispersedly formed. These connection conductive parts 191a-1
Reference numeral 91e is electrically connected to an extraction electrode of a piezoelectric resonator described later, or is electrically connected to external electrodes 191f to 191h and 191j formed on a side surface of the base substrate 191.

The cap member 192 is made of an appropriate material such as synthetic resin or metal, and has an opening below. Further, the opening of the cap material 192 is formed on the base substrate 191.
Is smaller than the area of the upper surface of the base material 191. Therefore, the lower end surface of the cap material 192 is joined to the upper surface of the base substrate 191 by using an insulating adhesive or the like.
92 is integrated with the base substrate 191. However, the size of the opening of cap material 192 may be selected such that it contacts the side surface of base substrate 191.

In this embodiment, two piezoelectric resonators 177 and 185 used in the seventh embodiment are used.
The layers are stacked as shown. Although not specifically shown in FIG. 50, spaces for preventing the vibration of the piezoelectric resonators disposed above and below are set between the piezoelectric resonators and between the piezoelectric resonators 17.
In order to provide between the base 7 and the base substrate 191, conductive adhesives 192A to 195 are used. That is, FIG.
At 0, each of the conductive adhesives 192A to 195 is schematically shown in a floating state, but is applied upon lamination. For example, the conductive adhesive 192A is used for bonding the piezoelectric resonator 177 and the piezoelectric resonator 185, and is interposed between the holding portions of the piezoelectric resonators 177 and 185 so as to have a predetermined thickness. Thereby, the piezoelectric resonator 177
A space having a predetermined thickness is formed between the piezoelectric resonator 185 and the piezoelectric resonator 185 so that the vibration of the piezoelectric vibrating portions of the piezoelectric resonators 177 and 185 is not hindered. Further, as shown in the figure, the conductive adhesive 192A is applied to the electrodes 182a to 182c and 183a formed on the side surfaces of the holding portions 182 and 183 of the piezoelectric resonator 177.
183c so as to reach the outer peripheral edges of the holding portions 182 and 183 in a connected state. Similarly, the other conductive adhesives 193 to 195 are formed to have a predetermined thickness in order to form a space for preventing the vibration of the piezoelectric vibrating portion of the piezoelectric resonator located above or below the conductive adhesive. .

The conductive adhesives 193 to 195 are also formed on the electrodes formed on the side surfaces of the respective piezoelectric resonators, the connection conductive portions on the base substrate 191, or the base substrate 19.
It is arranged so as to be electrically connected to external electrodes 191f to 191k formed on one side surface.

In the ladder type filter of this embodiment,
As described above, two first-type energy-trapping piezoelectric resonators 177 and 177 and two first-type energy-trapping piezoelectric resonators 185 and 185 are stacked to form a two-stage ladder-type piezoelectric resonator. A filter is configured. In addition, a plurality of piezoelectric resonators 17 are provided in a space formed by joining the base substrate 191 and the cap member 192.
Since 7,185 is surrounded, a ladder-type filter having excellent moisture resistance can be easily formed.

Ninth Embodiment FIG. 51 is an exploded perspective view of a ladder filter according to a ninth embodiment. In the ladder filter of the ninth embodiment,
This corresponds to a modification of the ladder filter of the eighth embodiment.

That is, also in this embodiment, a chip-type ladder-type filter is formed using a base substrate 196 and a cap member 192 which are configured in the same manner as the base substrate 191, although the shape of the connection conductive portion on the upper surface is different. Is done.

Further, on the base substrate 196, connection conductive portions 196a to 196f are formed. These connection conductive portions 196a to 196f are arranged so as to be electrically connected to external electrodes formed on the side surface of the base substrate 196 or to a piezoelectric resonator arranged above.

In this embodiment, a plurality of plate-shaped piezoelectric resonators 451 to 454 are stacked. At the time of joining these piezoelectric resonators 451 to 454 and joining the piezoelectric resonator 454 to the base substrate 196, as in the eighth embodiment,
192 to 195 such as a conductive adhesive are used. Also in FIG. 51, these conductive adhesives 192 to 195 are shown in a state of being floated inside, but in fact, predetermined adhesives are provided on the upper or lower surfaces of the piezoelectric resonators 451 to 454 or the lower surface of the base substrate 196. Is applied to have a thickness of Up to this point, the operation is the same as in the eighth embodiment. Also,
In the eighth and ninth embodiments, if an anisotropic conductive adhesive is used, the bonding material may not be formed separately. An example of such an anisotropic conductive adhesive is indicated by reference numeral 195A on the right side of FIG.

The present embodiment is characterized in that the piezoelectric resonators 451 to 451
Numeral 54 is that it is configured using only the piezoelectric vibrating portion of the above-described energy trap type piezoelectric resonator of the first type, that is, the piezoelectric resonator using the width expansion mode. That is, the piezoelectric resonator 451 is configured using a rectangular-plate-shaped piezoelectric ceramic plate 455 that is polarized in the thickness direction. Upper surface 4 of this piezoelectric ceramic plate 455
55a has a rectangular shape, the length of the short side is a, the length of the long side is b, and the Poisson's ratio of the material constituting the piezoelectric ceramic plate 455 is σ. / A is
The shape is determined so as to be within a range of ± 10% around a value that satisfies Expression (1) described above. Similarly to the piezoelectric resonator 177, the first and second resonance electrodes 456a and 456a are provided on the upper and lower surfaces of the piezoelectric ceramic plate 455, respectively.
6b is formed in an area much smaller than the main surface.

The first and second resonance electrodes 456a, 456b
By applying an AC voltage from the piezoelectric resonator 451
Is vibrated in the width expansion mode by the piezoelectric lateral effect. In this case, the node point of the vibration is located at the center of the side surface along the short side of the piezoelectric ceramic plate 455. Therefore, in the present embodiment, the extraction electrodes 457a to 457c and 458 for joining the piezoelectric resonator 451 are provided in the central region on the short side surface.
a to 458c are formed.

The piezo-resonator 454 is the same as the piezo-resonator 45.
1 is substantially the same as that of FIG. The difference is that the first and second resonance electrodes 456a, 456 formed on the upper and lower surfaces are different.
The only difference is the direction in which the electrodes 6b are drawn out.

In the piezoelectric resonator 452, the first and second resonance electrodes 457a and 457b
The piezoelectric resonator 451 is formed except that the piezoelectric resonator 451 is formed so as to have a considerably larger size than the piezoelectric resonators 451 and 456b.
It is configured similarly to. Further, the piezoelectric resonator 453 is
The configuration is the same as that of the piezoelectric resonator 452 except that the direction in which the electrodes are drawn is different.

Accordingly, also in the piezoelectric resonators 452 to 454, the vibration in the width expansion mode is excited by applying an AC voltage from the first and second resonance electrodes on both main surfaces. The resonance energy based on the vibration is effectively confined in each of the piezoelectric resonators 452 to 454.

On the other hand, in each of the piezoelectric resonators 451 to 454, as described above, since the vibration node point exists in the central region of the side surface along the short side, as described above, the extraction electrodes 457a to 457c and 458a to By joining using a conductive adhesive or the like 192A to 195 at the portion where the 458c is formed, the piezoelectric resonators 451 to 454 can be laminated and fixed without significantly affecting the resonance characteristics.

Also in the present embodiment, a two-stage ladder filter can be constructed, similarly to the ladder filters of the seventh and eighth embodiments. Moreover, in this embodiment, since the piezoelectric resonators 451 to 454 are configured using only the piezoelectric vibrating portions of the first type of piezoelectric resonator, the piezoelectric resonators 451 to 454 are extremely easily manufactured. And have increased mechanical strength.

In the ninth embodiment, each of the piezoelectric resonators 451 to 454 is formed using only the piezoelectric vibrating portion of the first type of energy trap type piezoelectric resonator. The ladder-type filter can be configured in the same manner as in the present embodiment by using only the piezoelectric vibrating portion of the energy trap type piezoelectric resonator. That is, instead of the piezoelectric resonators 451 to 454, the piezoelectric resonator may be configured using only the piezoelectric vibrating portion of the above-described energy trap type piezoelectric resonator of the second type.

In the ladder-type filters of the first to sixth embodiments described above, the ladder-type filters using the piezoelectric resonator with a built-in dynamic vibration absorbing portion have been described.
The piezoelectric resonator with a built-in dynamic vibration absorbing portion in the embodiment may not have the dynamic vibration absorbing portion.

<Explanation of the third type of energy trap type piezoelectric resonator used in the present invention> The third type piezoelectric resonator used in the present invention utilizes a new vibration mode found by the present inventors. This is a piezo-resonator.
This newly found vibration mode is shown in FIGS.
This will be described with reference to FIG.

Now, as shown in FIG. 52, the rectangular piezoelectric plate 5
Consider a model in which electrodes 522 and 523 are formed on the entire surfaces of both main surfaces of the P.21. The piezoelectric plate 521 has a rectangular planar shape. That is, the upper and lower surfaces have a rectangular planar shape. The piezoelectric plate 521 is uniformly polarized in the thickness direction, that is, in the direction of arrow P.

When the second harmonic of the bending vibration on the upper surface or the lower surface when the piezoelectric plate 521 is vibrated by applying an AC voltage from the electrodes 522 and 523 is analyzed by the finite element method, the plane of the piezoelectric plate 521 is analyzed. It was found that the vibration mode shown in FIG. 53 was excited in a certain range of the shape. FIG. 53 shows a vibration mode analyzed by the finite element method, in which the original shape is indicated by a line A. Here, a displacement state indicated by B and a displacement state opposite to the displacement state indicated by B are shown. Vibration is repeated between the states.

When the piezoelectric plate 521 on which the vibration of the second harmonic of the bending mode is excited is held at one end of a pair of side surfaces along a pair of short sides, as shown in FIG.
It was confirmed that vibration energy was confined.
That is, as shown in FIG. 54, the displacement distribution analyzed by the finite element method, the connecting portion 522 is connected to one end of the side surface 521a on the short side of the piezoelectric plate 521. In addition, the connecting portion 523 is connected to one end of the side surface 521b along the other short side.
In this case, the connecting portion 522 and the connecting portion 523 are
21 is connected to both ends of one diagonal line on the upper surface.

As is apparent from FIG.
22 and 523 are connected, and when the piezoelectric plate 521 is held by the connecting portions 522 and 523, it is understood that in the displacement state C, the displacement does not propagate to a portion outside the connecting portions 522 and 523. In other words, connecting portions 522 and 523
It can be seen that by connecting to the above position, the vibration of the second harmonic of the bending mode of the piezoelectric plate 521 can be confined to the portions up to the connecting portions 522 and 523.

When the charge distribution in the displacement state C shown in FIG. 54 was examined, the result shown in FIG. 55 was obtained. That is, on the upper surface of the piezoelectric plate 521, the region of the positive polarity is
It extends in a direction along the illustrated virtual line D, and this virtual line D
Extending substantially along two diagonals. In addition, a portion having a strong negative polarity appears near the other diagonal corner portion.

Therefore, in order to connect the connecting portions 522 and 523 to strongly excite the vibration oscillating between the displacement C shown in FIG. 54 and the opposite displacement state, the electric charge shown in FIG. It is considered that the resonance electrodes may be formed according to the distribution.

As described above, when the connecting portions 522 and 523 are connected to the rectangular piezoelectric plate 521, and the voltage is applied from the electrodes on both surfaces to excite, the second harmonic in the bending mode is strongly excited. The energy of the vibration is applied to the connecting portions 522 and 523.
Trapped by Such an effect is achieved by the piezoelectric plate 52
It has been found that only one dimension can be obtained if it is in a certain range.

That is, the present inventor excited the repeated vibration between the displacement state C shown in FIG. 54 and the reverse displacement state by using the piezoelectric plates 521 of various dimensions.
Let b be the length of the long side of the rectangular surface of the piezoelectric plate 521 and a be the length of the short side, and let the Poisson's ratio of the material forming the piezoelectric plate 521 be σ
Then, when the value satisfies the above expression (3), the vibration is strongly excited, and the first and second connecting portions 522, 5
It has been found that vibration energy can be effectively confined to the portion up to 23. That is, the displacement state was analyzed by the finite element method as shown in FIG. 54 using various ratios b / a and using various piezoelectric materials. As a result, the second harmonic of the bending mode is effectively reduced to the connecting portions 522, 5
23, the ratio b / a and the piezoelectric plate 521
It has been confirmed that it is sufficient that the Poisson's ratio σ of the material constituting satisfies the relationship shown in FIG. FIG. 56
From the result of (a), the ratio b / a is

[0210]

(Equation 10)

It can be seen that the length a of the short side and the length b of the long side should be selected so that Furthermore, it has been found that even when the ratio b / a is an integral multiple of (0.3σ + 1.48), vibration energy is confined in the same manner as described above.

Further, the inventor of the present application uses the piezoelectric plate made of a piezoelectric material having a certain Poisson's ratio σ to convert n in the expression (3) into:
The ratio was changed from 0.85 to 1.1, and the ratio of the displacement at the point Q having the largest displacement to the displacement at the point P having the smallest displacement shown in FIG. 54, that is, the relative displacement (%) was measured. The results are shown in FIG.

As is clear from FIG. 56B, when the value of n is in the range of 0.9 to 1.1, the relative displacement is 10
%. On the other hand, it has been found that when the relative displacement is 10% or less, there is substantially no problem in forming the resonator. Therefore, within a range of ± 10% from the value satisfying the expression (1), the vibration energy can be effectively confined in the piezoelectric vibrating portion.

As described above, in the piezoelectric vibrating portion where the length of the short side is a, the length of the long side b, and the Poisson's ratio of the material constituting the piezoelectric plate is σ, the above ratio b / a is expressed by the formula (3) It has been found that a piezoelectric resonator excellent in energy confinement efficiency can be provided by setting the value within the range of ± 10% from the value satisfying the above. Note that the vibration of the second harmonic in the bending mode exists in the center of the rectangular surface and the center of the side surface along both short sides when the connecting portions 522 and 523 are not connected to the piezoelectric plate 521. Has been confirmed to do so.

Specific Example of Third-Type Piezoelectric Resonator FIG. 57 is a plan view showing an example of a third-type piezoelectric resonator. FIG. 58 shows the shape of the lower electrode through the piezoelectric plate. It is the schematic plan view shown.

The piezoelectric resonator 531 has a rectangular piezoelectric plate 532.
And supporting portions 533 and 534, and holding portions 535 and 536. The piezoelectric plate 532 is made of a piezoelectric material such as, for example, lead zirconate titanate-based piezoelectric ceramics. In the case of piezoelectric ceramics, the piezoelectric plate 532 is uniformly polarized in the thickness direction. The piezoelectric plate 532 has a rectangular planar shape, and has a first side surface 532a on one end side along a short side.
Of the second side surface 532b along the short side is connected to the second support portion 534. In addition, outside the support portions 533 and 534, the support portion 5
Holding portions 535, 536 having a larger area than 33, 534
Are connected.

In the piezoelectric resonator 531, the piezoelectric plate 53
2, the first and second support portions 533, 534 and the first and second support portions
The holding portions 535 and 536 are prepared by preparing one piezoelectric plate and forming grooves 537 and 538 in the piezoelectric plate. That is, the piezoelectric plate 532, the first and second support portions 533, 534, and the holding portions 535, 536 are integrally formed of the same material. However, the piezoelectric plate 5
32, the first and second support portions 533 and 534, and the first and second holding portions 535 and 536 may be formed of different members, respectively, or may be integrated by being joined by an adhesive or the like. Good.

The piezoelectric plate 532 has a rectangular planar shape.
Assuming that the length of the long side of the rectangular surface is b, the length of the short side is a, and the Poisson's ratio of the material forming the piezoelectric plate 532 is σ, the ratio b / a is given by the above equation ( The value is within a range of ± 10% around a value satisfying 3).

On the upper surface of the piezoelectric plate 532, a first resonance electrode 538 is formed, and on the lower surface, the first resonance electrode 538 is formed.
A second resonance electrode 539 is formed so as to oppose to the piezoelectric element 38 via the piezoelectric plate 532. First and second resonance electrodes 5
Numerals 38 and 539 are formed so as to substantially coincide with the region of the positive polarity shown in FIG. That is, the first and second
55 correspond to the virtual line D shown in FIG.
, That is, in a direction substantially along one diagonal line.

[0220] The extraction electrode 5 is provided on the second holding portion 536.
40 is provided on the lower surface of the first holding portion 535 with the extraction electrode 5.
41 are formed. The first resonance electrode 538 is electrically connected to the extraction electrode 540 via the connection conductive portion 542, while the second resonance electrode 539 is electrically connected to the extraction electrode 541 via the connection conductive portion 543. It is connected to the.

In the piezoelectric resonator 531, the extraction electrode 54
By applying an AC voltage from 0,541,
An AC voltage is applied between the second resonance electrodes 538 and 539, whereby the vibration of the second harmonic in the bending mode described above is strongly excited.

In this case, the ratio b / a of the length of the long side and the length of the short side of the piezoelectric plate 532 is within ± 10% around the value satisfying the above-mentioned expression (3). Part 53
Vibration is effectively confined to the portion up to 3,534. Therefore, even if it is mechanically held by using the holding portions 535 and 536, the deterioration of the resonance characteristics hardly occurs. In other words, the energy trap type piezoelectric resonator 531 in which the vibration energy is effectively trapped in the portions up to the support portions 533 and 534 is provided.

Tenth Embodiment FIGS. 59 to 61 are an exploded perspective view, a perspective view showing the appearance, and a perspective view showing a spacer for explaining a ladder filter according to a tenth embodiment.

Referring to FIG. 59, in the tenth embodiment,
The resonance plates 581 and 582 and the first and second case substrates 583 and 584 are stacked. Second case substrate 5
A concave portion 584a is formed on the upper surface of 84, and a concave portion is also formed on the lower surface of the first case substrate 583.

The resonance plate 581 has a structure in which first and second spacer plates 585 and 586 are joined to both side edges of a second type piezoelectric resonator 554 utilizing a slip mode. The resonance plate 582 has a structure in which first and second spacer plates 587 and 588 are joined to both sides of a third type piezoelectric resonator 531B.

The structure of the piezoelectric resonator 531B is almost the same as that of the piezoelectric resonator 531 shown in FIG. The difference is only in the shape of the connection conductive part and the formation position of the extraction electrode.

Also, the first and second spacer plates 58
5, 586, 587 and 588 correspond to the first and the second shown in FIG.
It is configured similarly to the second spacer plates 29 and 30. In the ladder filter of the present embodiment, the first and second
Are laminated via a spacer 589 shown in FIG.

After the first and second resonance plates 581 and 582 are stacked, the rectangular frame-shaped spacer 589 has the piezoelectric resonator 554 and the first piezoelectric resonator 531.
It is inserted in order to secure a space not to hinder the vibration of the vibration part with B.

As described above, the resonance plates 581, 5
82, and the first and second case substrates 5
By laminating 83 and 584, a laminated body 590 shown in FIG. 61 can be obtained. The obtained laminate 59
0, the ladder-type filter 591 can be obtained by forming the external electrodes 590a, 590b and 590c, 590d on both side surfaces.

In the ladder-type filter 591, the external electrode 590a is used as an input terminal, the external electrode 590b is connected to a reference potential, and the external electrode 590c and the external electrode 590d are commonly connected and used as an output terminal. 62
Can be operated as a one-stage ladder filter.

In addition, as is apparent from the first to tenth embodiments, at least two piezoelectric resonators are stacked in the ladder filter of the present invention. Therefore, a chip-type ladder-type filter can be easily obtained. In addition, the above first to first
In each piezoelectric resonator of the fourth type, as described above, the vibration energy is effectively confined in the piezoelectric vibrating portion, so that even if the piezoelectric vibrating portion is mechanically supported in the holding portion, the resonance characteristics thereof hardly deteriorate. Therefore, as in the first to tenth embodiments, the resonance characteristics of each piezoelectric resonator can be exhibited as desired by forming a resonance plate by joining to another member in the holding portion. Therefore, it is possible to reliably provide a ladder-type filter having stable characteristics.

In the first to tenth embodiments, the first piezoelectric resonator and, if necessary, another piezoelectric resonator are joined.
Although the first and second spacer plates are joined on both sides to form a resonance plate, each resonance plate may be integrally formed of the same material. For example, FIG.
In the embodiment shown in FIG. 1, a rectangular piezoelectric plate is prepared, the piezoelectric plate is processed by a laser or the like so as to conform to the planar shape of the resonance plate 22, and a predetermined electrode pattern is formed on both sides, whereby the resonance plate 22 is formed. May be obtained. In this case, since the resonance plate 22 is formed of an integral member, the joining portion existing on the outer peripheral edge of the resonance plate 22 can be omitted, thereby improving the moisture resistance of the chip filter. . That is, in the obtained chip type filter, the invasion of moisture from the side of the resonance plate 21 can be reliably prevented.

In the first to third embodiments, as the piezoelectric resonator combined with the first type of piezoelectric resonator,
Although the fourth type of piezoelectric resonator using the slip mode has been described, various types of energy trapping type piezoelectric resonators such as those using the width expansion mode and those using the length mode are used as the combined piezoelectric resonator. Can be used.

Further, the electrode shape of the third type piezoelectric resonator is not limited to those shown in FIGS. 57 and 58. For example, as shown in FIGS. 63 and 64, a pair of first resonance electrodes 601a,
601b is provided on the lower surface with first resonance electrodes 601a and 601b.
The second resonance electrode 602 formed so as to face the front and back
a, 602b may be formed. In this case, the first and second resonance electrodes 601a and 602b
In the charge distribution shown in FIG. 5, it is formed in a portion having a strong negative polarity. Therefore, the piezoelectric resonator 531 shown in FIG.
Although the phases are opposite to each other, similarly, the 2n-th order vibration in the bending mode in which energy is confined in the piezoelectric vibrating portion is reliably excited.

[0235]

As described above, in the ladder-type filter of the present invention, at least two resonators of the series resonators and the parallel resonators are stacked in the thickness direction. Can be reduced. In addition, because of such a laminated structure, it is easy to configure the ladder-type filter as a chip-type component.

In the present invention, at least one of the series resonators and the parallel resonators includes a plate-shaped piezoelectric vibrating portion, a supporting portion connected to the piezoelectric vibrating portion, and a supporting portion. And an energy trapping type piezoelectric resonator having a connected holding portion and configured to prevent vibration energy from being transmitted to the supporting portion. Therefore, the piezoelectric resonator can be fixed to another piezoelectric resonator, a case substrate, or the like using the holding portion without deteriorating the resonance characteristics of the piezoelectric resonator.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view for explaining a conventional ladder-type filter.

FIG. 2 is a diagram showing a circuit configuration of a conventional ladder-type filter.

FIG. 3 is a perspective view for explaining a piezoelectric vibrating portion used in a piezoelectric resonator in a width expansion mode.

FIG. 4 is a schematic plan view for explaining a spreading mode.

FIG. 5 is a schematic plan view for explaining a width expansion mode.

FIG. 6 is a schematic plan view for explaining a width mode.

FIGS. 7A and 7B are diagrams showing a displacement distribution of a vibration in a width-spread mode analyzed by a finite element method, and a diagram for explaining coordinates in FIG. 7A;

FIG. 8 is a diagram showing a relationship between a position along the x direction and a displacement amount in the displacement distribution shown in FIG. 7;

FIG. 9 is a diagram showing a relationship between a Poisson's ratio and a dimensional ratio b / a for exciting a widening mode.

FIG. 10 is a diagram illustrating a relationship between a ratio b / a and a relative displacement amount in the displacement distribution illustrated in FIG. 7;

FIG. 11 is a diagram showing a relationship between a Poisson's ratio and a ratio b / a.

12A and 12B are a plan view and a side view, respectively, showing an example of a first energy trap type piezoelectric resonator.

FIG. 13 is a plan view showing another example of the first type of energy trap type piezoelectric resonator.

FIG. 14 is a plan view showing an example of a first type energy trap type piezoelectric resonator.

FIG. 15 is a side view showing an example of a second type energy trap type piezoelectric resonator.

16 is a perspective view of the piezoelectric resonator shown in FIG.

FIGS. 17A and 17B are a schematic diagram for explaining a vibration mode of a vibrating body that vibrates in a sliding vibration mode and a diagram showing a coordinate form in FIG. 17A;

FIG. 18 is a schematic side view showing a piezoelectric body.

FIG. 19 is a diagram showing a relationship between a Poisson ratio σ of a piezoelectric material and a ratio b / a.

FIG. 20 is a diagram showing a state in which the displacement distribution of vibration in the piezoelectric resonator of the second type is analyzed by the finite element method.

FIG. 21 is a diagram illustrating a relationship between an integer n and a relative displacement.

FIG. 22 is a side view showing an example of a second type of piezoelectric resonator.

FIG. 23 is a perspective view showing still another example of the second type piezoelectric resonator.

FIG. 24 is a plan view showing another example of the second type piezoelectric resonator.

FIG. 25 is a plan view showing still another example of the second type piezoelectric resonator.

FIG. 26 is a perspective view showing another example of the second type piezoelectric resonator.

FIG. 27 is a perspective view showing a structure in which a piezoelectric vibrating part, a support part, a dynamic vibration absorbing part, and a holding part for constituting a second type of piezoelectric resonator are integrated.

FIG. 28 is a perspective view showing a piezoelectric plate in which a connecting portion and a holding portion are integrated.

FIG. 29 is an exploded perspective view of the ladder-type filter according to the first embodiment.

FIG. 30 is a perspective view showing the appearance of the ladder filter of the first embodiment.

FIGS. 31 (a) and (b) are perspective views for explaining a piezoelectric resonator with a built-in dynamic vibration absorber used in the first embodiment.

FIG. 32 is a schematic plan view for explaining a connection state of terminal electrodes in the first embodiment.

FIG. 33 is a diagram illustrating a circuit configuration of a ladder-type filter according to the first embodiment.

FIG. 34 is an exploded perspective view for explaining a ladder-type filter according to the second embodiment.

FIG. 35 is a perspective view illustrating an appearance of a ladder-type filter according to a second embodiment.

FIGS. 36 (a) and (b) are plan views for explaining a piezoelectric resonator with a built-in dynamic vibration absorbing portion using a length mode used in the second embodiment.

FIG. 37 is a diagram illustrating a circuit configuration of a ladder-type filter according to the second embodiment.

FIG. 38 is an exploded perspective view showing a ladder-type filter according to a third embodiment.

FIG. 39 is a perspective view of a ladder-type filter according to a third embodiment.

FIG. 40 is a diagram illustrating a circuit configuration of a ladder-type filter according to a third embodiment.

FIG. 41 is an exploded perspective view for explaining a ladder-type filter according to a fourth embodiment.

FIG. 42 is a perspective view illustrating an appearance of a ladder-type filter according to a fourth embodiment.

FIG. 43 is a diagram illustrating a circuit configuration of a ladder-type filter according to a fourth embodiment.

FIG. 44 is an exploded perspective view for explaining a ladder-type filter according to a fifth embodiment.

FIG. 45 is a perspective view showing an outer tube of the ladder-type filter according to the fifth embodiment.

FIG. 46 is an exploded perspective view illustrating a ladder-type filter according to a sixth embodiment.

FIG. 47 is a perspective view showing the appearance of a ladder filter according to a sixth embodiment.

FIG. 48 is an exploded perspective view for explaining a ladder-type filter according to a seventh embodiment of the present invention.

FIG. 49 is a perspective view showing the appearance of a ladder-type filter according to a seventh embodiment.

FIG. 50 is an exploded perspective view for explaining a ladder-type filter according to an eighth embodiment.

FIG. 51 is an exploded perspective view for explaining a ladder-type filter according to a ninth embodiment.

FIG. 52 is a perspective view showing a piezoelectric plate as a model for describing a third type of piezoelectric resonator.

FIG. 53 is a schematic plan view showing a state in which the displacement state of the piezoelectric plate shown in FIG. 52 is analyzed by the finite element method.

FIG. 54 is a schematic cross-sectional view showing a state in which a displacement state of a structure in which a supporting portion and a holding portion are connected to the piezoelectric plate shown in FIG. 52 is analyzed by a finite element method.

FIG. 55 is a plan view showing the charge distribution in the displacement state of FIG. 54.

FIGS. 56 (a) and (b) are diagrams showing the relationship between the Poisson's ratio of the piezoelectric material and the ratio b / a and the relationship between the integer n and the relative displacement, respectively.

FIG. 57 is a plan view showing an example of a third type of piezoelectric resonator.

FIG. 58 is a schematic plan view showing the shape of the electrode below the piezoelectric resonator shown in FIG. 57 through the piezoelectric plate.

FIG. 59 is an exploded perspective view illustrating a ladder-type filter according to a tenth embodiment.

FIG. 60 is a perspective view showing a spacer.

FIG. 61 is a perspective view showing the appearance of a ladder-type filter according to a tenth embodiment.

FIG. 62 is a diagram illustrating a circuit configuration of a ladder-type filter according to a tenth embodiment.

FIG. 63 is a plan view for explaining another example of the third type of piezoelectric resonator.

FIG. 64 is a plan view showing a lower electrode shape through a piezoelectric plate in a third type of piezoelectric resonator.

[Explanation of symbols]

20: Ladder type filter 22, 23: Resonance plate 26, 27, 31 ... Piezoelectric resonator with built-in dynamic vibration absorbing part using slip mode 28, 32, 33 ... Piezoelectric resonator with built-in dynamic vibration absorbing part using width mode 28a ... Piezoelectric ceramic plate 28 b. Resonant parts 28 d and 28 e. Support parts 28 f and 28 g. Resonant parts 52b, 52c Support parts 52d, 52e Dynamic vibration absorbing parts 52f Connection parts 52g, 52h Holding parts 61 ... Piezoelectric resonators with built-in dynamic vibration absorbing parts

Continuation of the front page (56) References JP-A-4-282911 (JP, A) JP-A-55-85120 (JP, A) JP-A-3-108809 (JP, A) JP-A-5-145369 (JP) , A) Japanese Utility Model 2-100335 (JP, U) Japanese Utility Model 60-174325 (JP, U) Japanese Utility Model 60-172425 (JP, U) Japanese Utility Model 59-108330 (JP, U) Japanese Utility Model 53-25245 (JP, U) JP-A 62-44525 (JP, U) JP-A 62-42328 (JP, U) JP-B 53-14436 (JP, B2) JP-B 59-12811 (JP, U Y2) (58) Field surveyed (Int. Cl. ⁷ , DB name) H03H 9/00-9/215 H03H 9/54-9/60 H03H 3/00-3/04

Claims (19)

(57) [Claims] 1. A ladder-type filter comprising at least one series resonator forming a series arm and at least one parallel resonator forming a parallel arm, wherein the series resonator and / or the parallel resonance are provided. A small number of children
At least two plate-shaped resonators are stacked, and at least one of the stacked resonators has a short side length a and a long side length b. Some opposition
Piezoelectric material comprising and comprising a pair of matching rectangular surfaces
Where σ is the Poisson's ratio of the long side and the short side
b / a is, [number 1] Of a rectangular plate that is within ± 10% of the center
A piezoelectric vibrating portion, and a supporting portion connected to a center of a short side surface of the piezoelectric vibrating portion.
And a holding portion connected to an outer end of the support portion,
Utilizing the width expansion mode with the short side direction as the width direction
Ladder type filter which is a piezoelectric resonator . 2. At least one series member forming a series arm
A resonator and at least one parallel resonance forming a parallel arm
A ladder-type filter comprising a series resonator and / or a parallel resonator.
At least two plate-shaped resonators are stacked , and at least one of the stacked resonators is shared.
A pendulum having a plate-shaped piezoelectric body polarized in one direction;
First and second resonance electrodes formed on the piezoelectric body to apply an AC voltage in a direction orthogonal to the polarization direction,
The piezoelectric body surface parallel to the polarization direction has a rectangular shape, the length of the short side of the rectangular surface is a, the length of the long side is b, and the piezoelectric body is
When the Poisson's ratio of the constituting piezoelectric material is σ,
The ratio b / a is given by A piezoelectric vibrating unit is in the range of ± 10% around the a supporting part connected to the piezoelectric vibrating unit, pressure conductive resonator utilizing a shear mode and a connected retention portion to the support portion in it, ladder-type filter. 3. At least one series member forming a series arm
A resonator and at least one parallel resonance forming a parallel arm
A ladder-type filter comprising a series resonator and / or a parallel resonator.
At least two plate-shaped resonators are stacked , and at least one of the stacked resonators is shared.
A pendulum having a plate-shaped piezoelectric vibrating portion having a pair of opposed rectangular surfaces and four side surfaces connecting the pair of rectangular surfaces; a first vibrating portion formed on the pair of rectangular surfaces of the piezoelectric vibrating portion; A second resonance electrode; a support portion connected to one end of a side surface of the piezoelectric vibrating portion along a short side of the rectangular surface; and a holding portion connected to the support portion. When the length of the short side of the rectangular surface is a, the length of the long side is b, and the Poisson's ratio of the material constituting the piezoelectric vibrating portion is σ, the ratio b / a is given by: It is within a range of ± 10% about a value satisfying, 2n next by using the piezoelectric transverse effect (where, n is an integer) pressure that is configured to excite the vibration of the bending modes of the <br /> is the electric resonator, ladder-type filter. And wherein said piezoelectric vibration section further comprises a dynamic vibration portion provided between said supporting portion, a ladder-type filter according to any one of claims 1-3. On both sides according to claim 5, wherein said piezoelectric vibrating unit, respectively, the supporting portion and the holding portion are coupled, claims 1-3 noise
A ladder filter according to any of the claims. 6. The semiconductor device further comprises first and second case substrates, wherein the at least one resonator and at least one other resonator are sandwiched between the first and second case substrates. The ladder-type filter according to any one of claims 1 to 5 . 7. A base substrate, and a cap material fixed on the base substrate, wherein the at least two series resonators are laminated on the base substrate, and wherein the cap material is laminated. The cap material is fixed to the base substrate so as to surround the plurality of resonators,
The ladder-type filter according to any one of claims 1 to 5 . 8. All of the series resonators and the parallel resonators include a plate-shaped piezoelectric vibrating part, a supporting part connected to the piezoelectric vibrating part, and a holding part connected to the supporting part. The ladder filter according to any one of claims 1 to 7, which is provided on both sides of the vibrating portion. 9. on both sides of the direction connecting the holding portions provided on both sides of the piezoelectric vibrating unit, first, the second spacer plate is connected so as not to interfere with vibration of the pressure Denfu moving parts The ladder-type filter according to claim 8 , wherein a resonance plate is formed by the piezoelectric resonator and the first and second spacer plates. 10. The ladder filter according to claim 9 , wherein the piezoelectric resonator and the first and second spacer plates forming the resonance plate are integrally formed by the same member. 11. A least one side of the direction connecting the holding portions provided on both sides of the piezoelectric vibrating unit, at least one other piezoelectric resonator, connected so as not to interfere with the vibration of the piezoelectric vibrating portion to each other The ladder-type filter according to claim 8 , wherein 12. A first and a second spacer plate on both sides of the piezoelectric resonator and a connecting member composed of at least one piezoelectric resonator connected to the piezoelectric resonator, to prevent vibration of the piezoelectric resonator. It is connected so as not, whereby the resonant plate is formed, a ladder filter according to claim 1 1. Wherein said plurality of piezoelectric resonators constituting a resonance plate, and the first and second spacer plates are integrally formed by the same member, a ladder-type filter according to claim 1 2 . 14. The semiconductor device according to claim 1, further comprising first and second resonance electrodes provided on said piezoelectric vibrating section, and extraction electrodes formed on said holding section, wherein said first and second resonance electrodes are provided on said extraction electrodes. The ladder-type filter according to any one of claims 1 to 3 , which is electrically connected. 15. further comprising a plurality of external electrodes formed on an outer surface, said plurality of external electrodes are electrically connected to predetermined said extraction electrode, the ladder-type filter according to claim 1 4 . 16. At least one straight arm forming a serial arm
A column resonator and at least one parallel arm forming a parallel arm.
A ladder-type filter including a pendulum, wherein a small number of said series resonators and / or
At least two plate-like resonators are stacked, and at least one of the stacked resonators has a short side length a and a long side length b. Oh Ru opposed
When a pair of rectangular surfaces that match each other and the Poisson's ratio of the constituent material is σ, the ratio b / a of the length of the long side to the short side is expressed by the following equation. It is within a range of ± 10% around the short side direction
A ladder-type filter which is a rectangular plate-shaped piezoelectric resonator using a width expansion mode in which a width direction is defined as a width direction . 17. All resonators of the series resonator and the parallel resonator is configured by pressure conductive resonator utilizing the width expansion mode, the ladder-type filter according to claim 1 6. 18. A method according to claim 18 , wherein the plurality of width-expanding modes are used.
Pressure electric resonator, the main surfaces of the piezoelectric resonators adjacent to each other in the region near the center of the short sides are joined, according to claim 1
7. The ladder-type filter according to 7 . 19. The bonding of the piezoelectric resonators is performed using an adhesive, such that the adhesive forms a space for preventing vibration of the piezoelectric resonators on both sides to be bonded.
The ladder-type filter according to claim 18 , having a predetermined thickness.