JP3114522B2 - 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. Thus, co-pending U.S. patent application Ser. No. 07 / 941,081 and International Application Publication No. WO 92/16997 describe a ladder type that can be reduced in overall shape and configured as a surface mount electronic component. Filters have been proposed. 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 in which at least two resonators of a series resonator and a parallel resonator are connected in a horizontal direction is provided.

As the above-described energy trap type piezoelectric resonator, various types can be used. The first type of the energy-trap type piezoelectric resonator, the piezoelectric length of the short side is a, the length of the long sides has a pair of rectangular faces b der Ru
It has a vibrating part. When the Poisson's ratio of the material constituting the piezoelectric vibrating portion is σ, the ratio of the length of the long side to the length of the short side is b / a.
But,

[0012]

(Equation 4)

[0013] The center is within a range of ± 10% (where n is an integer) . Before Symbol a support portion connected to a central aspect <br/> the short side of the piezoelectric vibrating unit, a holding portion connected to the outer end of the support portion that are further provided. This first
Type is a pressure conductive resonator utilizing a width expansion mode.

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.

The second type of the above-described energy-trap type piezoelectric resonator is a plate-like piezoelectric body polarized in one direction, and the above-mentioned type for applying an AC voltage in a direction perpendicular to the polarization direction. And a first and second resonance electrodes formed on the piezoelectric body, wherein the piezoelectric body surface parallel to the polarization direction has a rectangular shape, and the length of the short side of the rectangular piezoelectric body surface is a, and the long side is When the length of b is b and the Poisson's ratio of the piezoelectric body is σ, the ratio b / a is

[0018]

(Equation 5)

A slip mode is used, which includes a piezoelectric vibrating portion having a range of ± 10% around the center, a supporting portion connected to the piezoelectric vibrating portion, and a holding portion connected to the supporting portion. It is an energy trap type piezoelectric 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.

In the energy trap type piezoelectric resonator of the second type as well, since the vibration energy is effectively trapped in the piezoelectric vibrating portion as described above, the energy trap type of the second type using the holding portion is used. The piezoelectric resonator can be supported, and even in such a case, the resonance characteristics are hardly deteriorated. 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.

A third type of the above-described energy trap type piezoelectric resonator is a plate-shaped piezoelectric vibrating portion having a pair of opposed rectangular surfaces and four side surfaces connecting the pair of rectangular surfaces.
Of the first and second resonance electrodes formed on the pair of rectangular surfaces of the piezoelectric vibrating portion, and a side surface 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, wherein the length of the short side of the rectangular surface is a, and the length of the long side is b, when the Poisson's ratio of the material constituting the piezoelectric vibrating part is σ, the ratio b / a is

[0023]

(Equation 6)

A value within a range of ± 10% with respect to a value satisfying (where n is an integer) is used to excite the vibration of a bending mode of the 2nd order (where m is an integer) using the piezoelectric transverse effect. This is an energy trapping type piezoelectric resonator configured to cause the energy to be confined. Also in the third type of piezoelectric resonator, the piezoelectric vibrating portion is configured to have the specific shape described above, so that the vibration in the bending mode of the order of 2 m 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.

In addition, since the piezoelectric vibrating portion is excited by the vibration of the bending mode of the 2m order, a ladder type filter having a wider band can be configured as compared with the conventional example.

A fourth type of the above-described energy trap type piezoelectric resonator is an energy trap type piezoelectric resonator having a structure in which a dynamic vibration absorbing section is provided between a piezoelectric vibrating section and a support section. 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,” pages 113 to 11
It is described on page 6 (issued by Corona). 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. Phenomenon
The dynamic vibration absorbing portion corresponds to a sub vibrator in the dynamic vibration absorbing phenomenon, and a support portion that vibrates due to vibration from the resonance portion corresponds to a main moving body.

In the ladder-type filter using the fourth type of piezoelectric resonator, at least one of the resonators is composed of the piezoelectric resonator having the above-mentioned dynamic vibration absorbing portion, so that the efficiency of confining 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.

The fourth type of energy trap type piezoelectric resonator is characterized by having a dynamic vibration absorbing portion as described above, and the piezoelectric vibrating portion itself is not particularly limited. is not. That is, in the above-described energy trapping type piezoelectric resonators of the first to third types, by providing the dynamic vibration absorbing portion, the slightly leaked vibration is suppressed by the dynamic vibration absorbing portion, thereby further improving the energy trapping efficiency. Can be enhanced.
Alternatively, in the fourth type of the energy trapping type piezoelectric resonator, another piezoelectric vibrating part different from the piezoelectric vibrating part of the first to the third type of the energy trapping type piezoelectric resonator, for example, a piezoelectric using a length mode is used. A vibrating part, a normal piezoelectric vibrating part using a sliding mode, a piezoelectric vibrating part using a square plate spreading mode, and the like can be appropriately used. That is, in the fourth type of energy trap type piezoelectric resonator using the dynamic vibration absorbing portion, it is possible to use the piezoelectric vibrating portion that is excited in various vibration modes according to the target resonance frequency. A ladder-type filter that can be used in various frequency bands can be easily obtained.

Moreover, the provision of the dynamic vibration absorbing portion effectively confines the vibration energy to the portion up to the dynamic vibration absorbing portion. Therefore, as in the first to third types of energy trapping type piezoelectric resonators. The holding unit can be used to hold the piezoelectric resonator, in which case,
Deterioration of resonance characteristics is unlikely to occur. Therefore, a ladder-type filter having stable characteristics and a small size, particularly, a small height can be easily formed.

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, and the piezoelectric vibrating portion is supported by the supporting portions on both sides thereof. 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, as described above, in the ladder-type filter of the present invention, at least two plate-like resonators are arranged in a horizontal direction.
That is, it has a structure connected in parallel with the mounting surface.
Specifically, for example, such a connection structure is such that the connection structure is disposed between the first and second case substrates, and the first and second case substrates are arranged.
In this case, the connection structure can be sandwiched between the case substrates described above, whereby a chip-type ladder-type filter can be easily formed. Alternatively, a chip-type ladder-type filter may be configured by stacking the connection structure on a base substrate and fixing a cap material to the base substrate so as to surround the connection structure.

Further, according to the present invention, as described above, at least one of the series resonators and the parallel resonators has the plate-shaped piezoelectric vibrating part, the supporting part, and the 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,
The first and second piezoelectric resonators are provided on both sides of at least two of the piezoelectric resonators.
Are provided. The first and second spacer plates are connected to each of the piezoelectric resonators so as not to hinder the vibration of the vibrating portion of each of the piezoelectric resonators, whereby the at least two piezoelectric resonators are connected to the first and second piezoelectric resonators. A resonance plate is constituted by the two spacer plates. When such a resonance plate is configured, a chip-type ladder-type filter having a laminated structure can be easily configured.

When the at least two piezoelectric resonators and the first and second spacer plates constituting the resonance plate are integrally formed by the same member, the space beside the resonator is provided. Is reliably bent, so that a ladder-type filter having excellent environmental resistance characteristics such as moisture resistance can be easily obtained.

Further, another resonance plate may be laminated on the resonance plate. That is, in the ladder-type filter of the present invention, two or more resonance plates may be provided.

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.

In the above-described first to third types of energy trapping type piezoelectric resonators, the piezoelectric material constituting the piezoelectric vibrating portion may be L
Piezoelectric single crystals such as iTaO ₃ and LiNbO ₃ are mentioned. 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.

[0040]

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 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 expanding 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 larger 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 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, when the b / a was variously changed and the above-mentioned widened vibration mode was excited, when b / a = −1.47σ + 1.88 was satisfied,
It was confirmed that the widening vibration mode was most strongly excited. When the displacement distribution in the piezoelectric resonator 205 in this case was analyzed by the finite element method, FIG.
The result shown in (a) 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 7)

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. 12 (a) and 12 (b) are a plan view showing an example of a piezoelectric resonator utilizing the widening mode manufactured based on the above findings, that is, a first type of piezoelectric resonator. It is a front view. 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. Further, supporting members 216 and 217 are connected to the center of the short side which is a node point when the piezoelectric vibrating portion 212 is excited in the widening vibration mode. The holding members 21 and 217 are provided at the outer ends of the support members 216 and 217, respectively.
8, 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.

[0061] Figure 13 shows another example of a pressure conductive resonator utilizing a width expansion mode. The piezoelectric resonator 231 has a piezoelectric vibrating part 232 as a rectangular plate-shaped vibrating body. However, in the piezoelectric vibrating portion 232, the pair of resonance electrodes 23 is formed on the upper surface of the piezoelectric plate 232 a so as to be along the long side edge.
2b and 232c are formed. The piezoelectric plate 232
a 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 / a of the length b of the long side of the piezoelectric vibrating portion 232 to the length a of the short side is within a range of ± 10% around a point satisfying the expression (1). Is set.

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 212b of the piezoelectric ceramic plate 312, the end surface 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 alternating current electrolysis is applied between the resonant 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 8)

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 in FIG. 19, the ratio b / a is

[0082]

(Equation 9)

By setting to, the transmission of displacement to the support side can be reduced. In other words, it has been found that the vibration energy can be effectively confined in the piezoelectric vibrating portion. Further, the ratio b / a is (0.3σ +
It was confirmed that vibration energy could be effectively confined even in the case of n times (1.48) (where n is an integer).

As described above, it has been found that 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, a piezoelectric material of Poisson's ratio sigma = 0.31 by the finite element method, was examined displacement distribution of the piezoelectric vibrating portion 341 of the case of the b / a = 1.57, shown in FIG. 2 0 The result was obtained.

Further, the displacement distribution of a resonator in which support portions 344 and 345 having the same width as that of the piezoelectric vibration portion 341 are integrally formed on the piezoelectric vibration portion 341 via the support portions 342A and 343A. When the same finite element method was used, the results shown in FIG. 20 were obtained.

As is clear 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 clear 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 11 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 b of the resonant portion along the polarization direction P, that is, 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 15 and 16 are formed, thereby increasing the energy trapping 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 portions 359 and 360 are formed.
Since the structure is the same as that of the piezoelectric resonator 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 section is within a range of ± 10% from the value represented by the equation (2), the vibration energy is effectively confined in the resonating section. 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, and a smaller piezoelectric resonator can be provided. The piezoelectric resonator 351
Is a fourth type of piezoelectric resonator used in the present invention since it has the dynamic vibration absorbing portions 359 and 360 as described above.

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 using an elongated rectangular piezoelectric ceramic plate 372 that has been polarized along the longitudinal direction B. 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 in the slip mode as in the piezoelectric resonator 311 of FIG.
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 portion 135 is polarized so as to be along the direction of arrow P shown in the figure, that is, along the length direction 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 391, 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 clear 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 excitation 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 required, 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 of 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 an 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 a dynamic vibration absorbing section built-in type piezoelectric resonator 26, 27 utilizing a sliding vibration mode.
And a piezoelectric resonator 28 with a built-in dynamic vibration absorbing portion using a width expansion mode, which is bonded to and integrated with the piezoelectric resonator 28. Further, a spacer plate having the same thickness as the piezoelectric resonators 26 to 28 with a built-in dynamic vibration absorbing portion is further outwardly provided. 29 and 30 are joined by using an adhesive. 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. Notches 29a 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 each other forms 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 absorber, 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.

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-like 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 absorbing portion shown in FIGS. 31 (a) and 31B
It may be formed by machining a single piezoelectric ceramic plate, but each part may be formed separately and connected to each other by an adhesive or the like. For example, FIG.
Instead of the piezoelectric ceramic plate 28a shown in (b), the supporting portions 28d and 28e, the dynamic vibration absorbing portions 28f and 28g, the connecting portions 28h and 28i, and The members forming 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 by further joining the first and second spacer plates 29 and 30 to the side. Is configured.

On the upper surface side of the resonance plate 22,
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.

The second resonance plate 24 has the same structure as the piezoelectric resonator 26 and has the same structure as the piezoelectric resonator 26 on both sides of the piezoelectric resonator 31 with a built-in dynamic vibration absorber using a sliding vibration mode, similar to the piezoelectric resonator 28 with a built-in dynamic vibration absorber. The piezoelectric resonators 32 and 33 with a built-in dynamic vibration absorbing portion using the width vibration 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 resonators 32, 3
The structure itself of 3 is the same as the above-described piezoelectric resonator 26 and the piezoelectric resonator 28, and thus the detailed description thereof is 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 separation 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 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 expansion 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.

Further, in the ladder type filter 20, FIG.
As is clear from FIG. 7, in the resonance plate 22, the plate-shaped piezoelectric resonators 26 to 28 are connected in the lateral direction. Similarly, also in the resonance plate 24, the plate-shaped piezoelectric resonators 31 to 33 are connected in the lateral direction. Therefore, a three-stage chip-type ladder-type filter can be configured without increasing the thickness significantly. That is, since the plurality of plate-shaped piezoelectric resonators are connected in the horizontal direction that is the direction parallel to the mounting surface, it is possible to promote the reduction in height of the ladder-type filter.

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

Second Embodiment FIG. 34 is an exploded perspective view of a T-type connection filter used in a ladder-type filter according to a second embodiment, and FIG.
FIG. 3 is a perspective view showing an appearance of the T-type filter.

The T-type filter 70 includes a case substrate 71,
It is configured by laminating a resonance plate 72 and a case substrate 73. The case substrates 71 and 73 are
It is configured similarly to the case substrates 21 and 25 of the embodiment. That is, a concave portion 73 a is formed on the upper surface of the case substrate 73, and a similar concave portion is formed on the lower surface of the case substrate 71, although not particularly shown.

On the other hand, the resonance plate 72 has substantially the same configuration as the resonance plate 22 used in the first embodiment. That is, the piezoelectric resonator 28 with a built-in dynamic vibration absorbing portion using the width expansion mode is arranged at the center, and the piezoelectric resonators 26 and 27 with a built-in dynamic vibration absorbing portion using the sliding mode are arranged on the sides.
Are bonded, and further, spacers 29 and 30 are bonded to the outside. However, in this embodiment, the piezoelectric resonator 2
8, the piezoelectric resonators 26 and 27 are provided on the edge side where the electrode 28m connected to the resonance electrode 28c is drawn out.
The electrodes 72a and 72b connected to one of the resonance electrodes are also drawn out.

As shown by a broken line on the right side in FIG. 34, the electrode 28o electrically connected to the resonance electrode 28n is also electrically connected to the other resonance electrode of the piezoelectric resonators 26 and 27 on the lower surface side. The electrodes 72c and 72d are drawn to the same edge side.

As is clear from FIG. 35, in the ladder-type filter 70 obtained by laminating the above-mentioned members, the terminal electrodes 70a to 70f are formed according to the positions where the electrodes 28m and 72a to 72d are formed. Is formed. Therefore, the terminal electrode 70c is connected to the input terminal, the terminal electrode 70b is connected to the ground potential, the terminal electrode 70a is used as the output terminal, and the terminal electrodes 70d to 70f are commonly connected, so that the T-type filter shown in FIG. Is configured.

The filter 70 is connected to the π-type connection filter shown with reference to FIGS. 37 and 38 to form a three-stage ladder-type filter. This π-type filter will be described with reference to FIGS. 37 and 38.

The π-type filter 80 has a structure in which a case substrate 81, a resonance plate 82 and a case substrate 83 are laminated. The case substrates 81 and 83 have the same configuration as the case substrates 71 and 73 shown in FIG. That is, a concave portion is formed on the lower surface of the case substrate 81, and a concave portion 83a is formed on the upper surface of the case substrate 83.

On the other hand, the resonance plate 82 has substantially the same configuration as the resonance plate 24 of the first embodiment. The difference is that the resonance electrodes 32a, 33a on the upper surfaces of the piezoelectric resonators 32, 33 with a built-in dynamic vibration absorbing portion using the width expansion mode.
Are drawn out to one edge side of the resonance plate 82, and as shown in the right side of the broken line in FIG. 37, all of the resonance electrodes on the lower surface are drawn out to the other edge side of the resonance plate 82. Is to be. The other points are the same as those of the resonance plate 24, and the corresponding parts are denoted by the same reference numerals, and the description thereof is omitted.

As shown in FIG. 38, this π-type filter 8
0, the terminal electrodes 80a to 80f are formed on the side surfaces,
The terminal electrodes 80a and 80b are commonly connected and used as an output terminal, and the terminal electrodes 80c and 80d are connected to the ground potential.
By connecting 0g and 80f in common and using them as input terminals,
The π-type filter shown in FIG. 39 is configured.

Therefore, by connecting the output terminal of the T-type filter 70 and the input terminal of the π-type filter 80,
A ladder-type filter of a stage is configured. In other words, T
By connecting the type filter 70 and the π-type filter 80, a ladder-type filter having the same number of stages as the ladder-type filter of the first embodiment can be configured.

[0141] ladder-type filter of the third embodiment The third embodiment, FIGS. 40 and 41
42 and 43 shown in FIG.
And a ladder-type filter 100 having a three-stage ladder-type filter as in the second embodiment.

The T-type filter 90 shown in FIGS.
Is similar to the case of the T-type filter 70 of the second embodiment.
It has a structure in which case substrates 71 and 73 and a resonance plate 92 are stacked. In the resonance plate 92, a piezoelectric resonator 93 with a built-in dynamic vibration absorbing portion utilizing a width expansion mode is disposed at the center. The piezoelectric resonator 93 has the same structure as that of the piezoelectric resonator 28 with a built-in dynamic vibration absorbing portion using the width expansion mode used in the first embodiment.

On the side of the piezoelectric resonator 93, piezoelectric resonators 94 and 95 with a built-in dynamic vibration absorbing portion utilizing a sliding mode are joined by bonding the holding portions. The piezoelectric resonator 94 has a shape shown in the figure by machining a piezoelectric ceramic plate.
a. In the resonance section 94a, polarization processing is performed so that the polarization axis direction is along the length direction of the piezoelectric plate. On the upper surface of the resonance portion 94a, resonance electrodes 94b and 94c are formed along a pair of opposing edges. Therefore, by applying an AC voltage from the resonance electrodes 94b and 94c, the resonance portion 94a resonates in the slip vibration mode.

In the figure showing the shape of the lower electrode on the right side of FIG. 40, the hoop of the resonator 94 is shown by a broken line. The shape of the resonator 94 will be described with reference to this figure.
The resonating portion 94a includes supporting portions 94d, 9 having a relatively narrow width.
4e are connected, and dynamic vibration absorbing portions 94f and 94g are formed at outer ends of the support portions 94d and 94e. Also,
A connecting portion 94 is provided on the outer side surface of the dynamic vibration absorbing portions 94f and 94g.
Holding parts 94j and 94k are connected via h and 94i. Details of each portion outside the resonance portion 94a are the same as those of the piezoelectric resonator 28.

The piezoelectric resonator 95 using the other slip mode has the same configuration as the piezoelectric resonator 94. Spacers 96 and 97 are bonded outside the piezoelectric resonators 94 and 95. Spacer 96,
97 is configured to have the same thickness as the piezoelectric resonators 93 to 95, and has cutouts 96a and 97a on the piezoelectric resonators 94 and 95 side. These notches 96a, 97a
This is provided so as not to hinder the vibration of the vibrating portions of the piezoelectric resonators 94 and 95.

The resonance plate 92 is connected to the case substrate 71,
73, and the terminal electrodes 90a
By forming 90f, a T-type filter similar to the T-type filter 70 of the second embodiment can be obtained (FIG. 41). That is, the terminal electrode 90c is connected to the input terminal, the terminal electrodes 90d to 90f are commonly connected, the terminal electrode 90b is connected to the ground potential, and the terminal electrode 90a is used as the output terminal.

On the other hand, as shown in FIG. 42, the π-type filter 100 has substantially the same configuration as the π-type filter 80 in the second embodiment. That is, the case substrate 81,
It is configured by laminating with a resonance plate 101 interposed between 83. The resonance plate 101 is different from the resonance plate 82 in that a piezoelectric resonator 102 with a built-in dynamic vibration absorbing portion using a sliding vibration mode is used at the center. The piezoelectric resonator 102 with a built-in dynamic vibration absorber is configured similarly to the piezoelectric resonator 94 with a built-in dynamic vibration absorber used in the T-type filter 90.

As shown in FIG. 43, the case substrate 8
1. A π-type filter is formed by forming terminal electrodes 100a to 100f on a laminate obtained by laminating the resonance plate 101 and the case substrate 83. That is,
The terminal electrodes 100a and 100b are commonly connected to form an output terminal, the terminal electrodes 100c and 100d are connected to a ground potential,
By connecting the terminal electrodes 100e and 100f in common and using them as input terminals, it is possible to operate as a π-type filter. Therefore, as in the case of the second embodiment, a three-stage ladder filter can be formed by connecting the T-type filter 90 and the π-type filter 100.

[0149] The ladder filter 120 of the fourth embodiment The fourth embodiment will be described with reference to FIGS. 44 and 45.

In this embodiment, when the piezoelectric resonators 26 and 28 are 1
It is integrated as a single resonance plate 121. That is, the piezoelectric resonators 26 and 28 are bonded via the spacer 122, the spacer 123 is bonded to the side of the piezoelectric resonator 28, and the spacer 124 is bonded to the outside of the piezoelectric resonator 26. Is configured. On the other hand, the resonance plate 121 is
By sandwiching and laminating at 5,126, the laminate shown in FIG. 45 is obtained.

A terminal electrode 120a is provided on the opposite end face of the laminate.
By forming ~ 120d, a one-stage ladder-type filter is formed. That is, the terminal electrode 120a is connected to the ground potential, the terminal electrode 120b is used as an input terminal, and the terminal electrodes 120c and 120d are commonly connected and used as an output terminal, whereby a one-stage ladder filter is configured as shown in FIG. Is done. Further, by stacking a plurality of the resonance plates 121 via a cavity forming spacer therebetween,
A ladder-type filter having more than two stages can be easily formed.

Fifth Embodiment FIG. 47 is an exploded perspective view for explaining a ladder filter according to a fifth embodiment, and FIG. 48 is a perspective view showing the appearance of the ladder 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, a 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 on 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 device operates as a width mode resonator using the piezoelectric longitudinal effect. Note that the resonance electrodes 139a and 139b
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. 48 on both end surfaces of the obtained laminate.

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

Sixth Embodiment The structure of a ladder filter 150 according to a sixth embodiment is as follows.
FIG. 50 is an exploded perspective view, and FIG. 51 is an external perspective view.

This embodiment corresponds to a modification of the ladder filter of the fifth 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. This piezoelectric resonator 155, 1
56 is a piezoelectric resonator 138 used in the fifth embodiment.
It is configured similarly to.

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 one of the resonance electrodes of the piezoelectric resonators 153 and 154, respectively. Is electrically connected to 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. 157,
158 denotes a case substrate, and 159a to 159c denote cavity forming spacers.

[0165] A laminate obtained by laminating the above members is
By forming the external electrodes 150a to 150f as shown in FIG. 51, the ladder-type filter 15 of the sixth embodiment is formed.
0 is obtained.

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

Seventh Embodiment FIG. 52 is an exploded perspective view for explaining a ladder filter according to a seventh embodiment, and FIG. 53 is a perspective view showing an appearance of the ladder filter.

The ladder-type filter 160 of this embodiment has the same configuration as that of the fifth embodiment except that the first and second resonance plates have different structures. With reference to FIG. 52, the first resonance plate 161 includes a piezoelectric resonator 162 with a built-in dynamic vibration absorber using a sliding mode, and a piezoelectric resonator 163 with a built-in dynamic vibration absorber using a spread 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 ダ ー 160f, a ladder filter 160 shown in FIG. 53 is obtained. Also in this embodiment, as in the fifth 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.

Eighth Embodiment In the first to seventh embodiments described above, the piezoelectric resonator with a built-in dynamic vibration absorber is formed by laminating a plurality of members such that the main surface thereof is horizontal. A ladder-type filter was configured. However, the ladder-type filter of the present invention is not limited to a ladder-type filter having a structure in which a plurality of piezoelectric resonators are stacked so that the main surface faces in the horizontal direction. The eighth embodiment is an example of a structure in which a plurality of piezoelectric resonators are stacked in such a manner that the main surface faces in the vertical direction.

Referring to FIG. 54, ladder type filter 17
0, the piezoelectric resonators 171 and 173 with a built-in dynamic vibration absorbing portion in the width expansion mode using the piezoelectric transverse effect and the piezoelectric resonators 17 with the built-in dynamic vibration absorbing portion in the width expanding mode using the piezoelectric longitudinal effect.
2, 174 are alternately stacked in the lateral direction via spacers 175 as shown. It should be noted that substantially U-shaped spacers 176 and 177 are bonded to the outside of the piezoelectric resonator 171 and the outside of the piezoelectric resonator 174, respectively.

The plurality of spacers 175 and the spacers 176 and 177 are bonded to the holding portions of the respective piezoelectric resonators. Therefore, in the structure in which the plurality of piezoelectric resonators 171 and 174 are bonded and integrated using the spacers 175, 176 and 177, the vibration of the resonance part and the dynamic vibration absorbing part of each of the piezoelectric resonators 171 to 174 is not hindered. .

In this embodiment, the piezoelectric resonator 171 described above is used.
To 174 are bonded together with spacers 175 to 177 to form case substrates 178 and 17 on the upper and lower surfaces of the integrated structure.
9 are stacked.

FIG. 55 shows the appearance of the ladder filter 170 thus obtained. The connection with the outside is made by the terminal electrodes 170a to 170 formed on the end faces of the obtained laminate.
d, 170e to 170h. That is, the terminal electrodes 170a and 170g are connected to the ground potential,
The terminal electrodes 170b to 170d are commonly connected, and the terminal electrode 1
A two-stage ladder-type filter is configured by connecting 70e and 170f in common to form an output terminal and the terminal electrode 170h to an input terminal.

Ninth Embodiment In the above-described embodiment, a ladder filter is constituted by using a plurality of piezoelectric resonators having a dynamic vibration absorbing portion.
In the ladder-type filter of the present invention, it is only required that at least one piezoelectric resonator is constituted by a piezoelectric resonator with a built-in dynamic vibration absorber. Such an embodiment will be described with reference to FIGS.

Ladder type filter 18 according to the ninth embodiment
0, the case substrate 18 above and below the resonance plate 181
2,183 are stacked. Case substrates 182, 183
Has the same configuration as the case substrate used in the first embodiment described above.

In the resonance plate 181, the piezoelectric resonators 184 and 185 with a built-in dynamic vibration absorbing section and the piezoelectric resonators 186 and 187 in the thickness shear vibration mode using a normal TS mode having no dynamic vibration absorbing section are formed. Spacer 188,
The layers are stacked in the horizontal direction via 189 and 190. The spacers 188 to 190 are made of insulating ceramics or synthetic resin, and are bonded near both ends of each piezoelectric resonator.

Further, the outermost spacers 191 and 19
2 are bonded together, whereby the resonance plate 1
81 are configured. The spacers 191 and 192 can also be made of insulating ceramics or synthetic resin, and are adhered to the vicinity of both ends on one main surface side of the piezoelectric resonators 181 and 187.

By the way, as shown in FIG. 57, the piezoelectric resonator 184 with a built-in dynamic vibration absorbing portion utilizing the slip vibration mode has a structure in which a resonance electrode 184b is formed on one main surface of a rectangular ceramic piezoelectric plate 184a. Have. Resonant electrode 1
84b is electrically connected to an electrode 184c formed near one end of the piezoelectric ceramic plate 184a on the illustrated side main surface. In this embodiment, two laterally extending grooves 184d and 184e are formed in the piezoelectric ceramic plate 184a.
The electrode 184f is located between the groove 184e and the other end of the piezoelectric ceramic plate 184a.
h is formed. This structure corresponds to the piezoelectric ceramic plate 1
84a, the electrodes 184c, 1 having the same area at both ends
After forming 84h and forming an elongated electrode so as to connect them, the grooves 184d and 184e are formed by dicing or the like.

On the other hand, the same applies to the other end face of the piezoelectric ceramic plate 184a, except that the grooves 184d and 184e are
By forming two grooves 184i and 184j on opposite sides of the piezoelectric ceramic plate 184a at the center in the length direction, a resonance electrode and an electrode connected to the resonance electrode are formed.

Therefore, a portion where the resonance electrodes on both sides overlap with each other via the piezoelectric ceramic plate 184a, that is, the groove 184 is formed.
The portion sandwiched between d and 184i is configured as a resonance portion that resonates in the slip vibration mode.

The piezoelectric ceramic portion between the grooves 184d and 184e and the piezoelectric ceramic portion between the grooves 184i and 184j constitute dynamic vibration absorbing portions. The known piezoelectric resonators 186 and 187 in the slip vibration mode using the TS mode have a well-known electrode structure in which a pair of resonance electrodes overlapping each other via a piezoelectric ceramic plate are formed at the center of a rectangular plate-shaped piezoelectric ceramic plate. It is comprised so that it may have. However, the resonance electrodes on both main surfaces are drawn to different ends.

The ladder-type filter 180 of this embodiment is provided with case substrates 182 and 18 above and below the resonance plate 181.
3 are bonded to each other, and a predetermined terminal electrode is formed on the opposite end face of the obtained laminated body. Can be configured. Also in this embodiment, the ladder-type filter is configured using the piezoelectric resonator with a built-in dynamic vibration absorber, so that the bandwidth can be increased as compared with the ladder-type filter using the piezoelectric tuning fork-type resonator. .

In the ladder filters of the first to ninth embodiments described above, a ladder filter using a piezoelectric resonator having a built-in dynamic vibration absorber has been described. It may not be provided with a dynamic vibration absorbing portion.

Tenth Embodiment FIG. 58 is an exploded perspective view of a ladder filter according to a tenth embodiment of the present invention.

In this embodiment, the resonance plate 19 is provided in the space defined by the base substrate 193 and the cap member 194.
5 are arranged. The base substrate 193 is made of an appropriate insulating material such as an insulating ceramic such as alumina or a synthetic resin. On the base substrate 193, connection conductive portions 193a to 193c are formed. These connection conductive portions 193a to 193c are electrically connected to lead electrodes of a piezoelectric resonator described later, and are connected to any of the external electrodes 193d to 193g formed in cutouts formed on the side surfaces of the base substrate 193. It is electrically connected.

The cap member 194 is made of an appropriate material such as a synthetic resin or metal, and has an opening below.
Further, the opening of the cap material 194 is
3 is smaller than the area of the upper surface. Accordingly, the cap material 194 is integrated with the base substrate 193 by being joined from the lower end surface of the cap material 194 to the upper surface of the base substrate 193 using an insulating adhesive or the like. However,
The size of the opening of the cap material 194 depends on the size of the base substrate 19.
3 may be selected so as to be in contact with the side surface.

In this embodiment, the resonance plate 195 is different from that of the first embodiment in that the electrode lead-out portion is slightly different and that the first and second spacer plates 144 and 145 are not provided.
It has the same configuration as the resonance plate 135 shown in FIG. That is, the piezoelectric resonators 142, 1 shown in FIG.
43 are connected laterally so as not to hinder the vibrations of the piezoelectric vibrating portions 196a and 197a, so that the resonance plate 19
5 are configured.

As described above, in the present invention, the two resonators connected in the horizontal direction may be integrated so as to form a resonance plate only with the at least two resonators.

The piezoelectric resonator 196 and the piezoelectric resonator 1
The 97 piezoelectric vibrating portions 196a and 197a have substantially the same configuration as the piezoelectric vibrating portions of the piezoelectric resonators 143 and 142 described above, respectively. However, the piezoelectric resonators 196 and 197 have no dynamic vibration absorbing portion.
That is, the piezoelectric resonator 196 is configured by the above-described second type piezoelectric resonator, and the piezoelectric resonator 197 is configured by the first type piezoelectric resonator.

The two piezoelectric resonators 196 and 197 are
Retainers 196b, 197b and 196c, 197 of each other
and c are combined to be integrated. The fixing of the resonance plate 195 to the base substrate 193 is performed using a conductive adhesive. That is, the extraction electrode 199a connected to one of the resonance electrodes of the piezoelectric resonator 196 and the resonance electrode on the upper surface of the piezoelectric resonator 197 is coupled to the connection conductive portion 193a via the conductive adhesive 198a. Similarly, the extraction electrode electrically connected to the resonance electrode on the lower surface of the piezoelectric resonator 197 is
8b, it is electrically connected to the connection conductive part 193b, and is also physically joined. Although not shown in FIG. 58, the extraction electrode connected to the other resonance electrode of the piezoelectric resonator 196 and formed on the lower surface of the piezoelectric resonator 196 is also connected to the above-described electrode via a conductive adhesive. It is electrically connected to the connection conductive part 193c.

In this case, the conductive adhesive 198a, 1
By applying 98b to a predetermined thickness, a space is formed between the piezoelectric resonators 196 and 197 and the base substrate 193 so as not to hinder the vibration of the piezoelectric vibrating portions 196a and 196b of the piezoelectric resonators 196 and 197. be able to. Note that, instead of the conductive adhesive, the resonance plate 195 is connected to the base substrate 19 via a spacer for securing the above space.
3 may be attached.

In the ladder filter of this embodiment,
Two piezoelectric resonators 196 and 197 are connected in the lateral direction and integrated. Therefore, a chip-type piezoelectric filter that can promote reduction in height can be easily configured. Further, a plurality of piezoelectric resonators 196 and 197 are provided in a closed space formed between the base substrate 193 and the cap member 194.
Is surrounded, it is easy to construct a ladder-type filter having excellent environmental resistance characteristics such as moisture resistance.

<Description 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. 59, 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 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 planar shape of the piezoelectric plate 521 is within a certain range. It was found that the vibration mode shown in FIG. FIG.
0 indicates a vibration mode analyzed by the finite element method,
The original shape is shown by the line A, where the vibration is repeated between a displacement state shown by B and a displacement state opposite to the displacement state shown by B.

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. 61, the connection portion 522 is connected to one end of the short side surface 521a of the piezoelectric plate 521, as shown in the displacement distribution analyzed by the finite element method. 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 clear 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.

[0203] Examination of charge distribution in the displacement state C shown in FIG. 61, the results shown in FIG. 6 2 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. 61 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 of 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 inventor of the present application excited vibrations repeatedly between the displacement state C shown in FIG. 61 and the reverse displacement state by using the piezoelectric plates 521 having 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. 61 using various ratios b / a and various piezoelectric materials. As a result, the second harmonic of the bending mode is effectively reduced to the connecting portions 522, 5
It has been confirmed that the ratio b / a and the Poisson's ratio σ of the material forming the piezoelectric plate 21 should satisfy the relationship shown in FIG. FIG. 63
From the result of (a), the ratio b / a is

[0207]

(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 a piezoelectric plate made of a piezoelectric material having a certain Poisson's ratio σ to convert n in the equation (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. 61, that is, the relative displacement (%) was measured. The results are shown in FIG.

As is clear from FIG. 63 (b), 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 ( 3 ), the vibration energy can be effectively confined in the piezoelectric vibrating portion.

As described above, in the piezoelectric vibrating portion in which 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 equation ( 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. 64 is a plan view showing an example of the third-type piezoelectric resonator. FIG. 65 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.

[0215] 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
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
62 correspond to the virtual line D shown in FIG.
, That is, in a direction substantially along one diagonal line.

On the second holding section 536, the extraction electrode 5
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 32 is within ± 10% around the value satisfying the above equation (3). Part 533,
Vibration is effectively confined to the portion up to 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.

Eleventh Embodiment FIG. 66 is an exploded perspective view of a ladder-type filter according to an eleventh embodiment of the present invention, and FIG. 67 is a perspective view showing the appearance.

The ladder-type filter of this embodiment has a resonance plate 551 and case substrates 552 and 553 attached to the upper and lower sides of the resonance plate 551. The resonance plate 551 includes a third type of piezoelectric resonator 531A configured similarly to the first piezoelectric resonator 531. The piezoelectric resonator 531A is different from the first piezoelectric resonator 531 shown in FIGS. 64 and 65 except that the shapes of the connection conductive portions 542 and 543 formed on the upper surface and the lower surface are slightly different.
It is configured similarly to. Therefore, the same portions are denoted by the same reference numerals, and description thereof will be omitted.

In this embodiment, the energy trap type piezoelectric resonators 554 and 555 utilizing the slip mode are joined to the outside of the piezoelectric resonator 531A. In the piezoelectric resonator 554, grooves 558 and 559 are formed in an elongated rectangular piezoelectric plate, and a portion sandwiched between the grooves 558 and 559 is configured as a piezoelectric vibrating portion. Piezoelectric vibrator 56
0, the piezoelectric plate is in the direction of arrow P, ie, the piezoelectric resonator 55
4 is polarized so as to extend in the longitudinal direction. The planar shape of the piezoelectric vibrating part 560 is the same as that described above, where the length of the long side is b, the length of the short side is a, and the Poisson's ratio of the material forming the piezoelectric vibrating part 560 is σ. Is selected so as to satisfy the following equation ( 2 ). On the other hand, the first and second resonance electrodes 561 and 562 are formed on the piezoelectric resonator 554 along the side edges on the upper surface.
On the other hand, also on the other surface, the first and second resonance electrodes 563, 563
564 are formed. In FIG. 66, the electrode shape on the lower surface of the resonance plate 551 is schematically shown on the right. In the piezoelectric resonator 554, the first and second resonance electrodes 561 and 562 are electrically connected to extraction electrodes 565 and 566 formed on holding portions at both ends, respectively. Similarly, on the lower surface, the first and second resonance electrodes 563 and 564 are electrically connected to the extraction electrodes 567 and 568, respectively. Note that the piezoelectric resonator 555 has the same configuration as the piezoelectric resonator 554.

In the piezoelectric resonator 554, the first and second resonance electrodes 561 and 562 and the first and second resonance electrodes 56
By applying an AC voltage between 3,564, the piezoelectric vibrating section 560 is excited in the slip mode. Further, since the piezoelectric vibrating section 560 has the specific shape, the resonance energy is effectively confined in the piezoelectric vibrating section 560.
That is, even if mechanical support is performed using the holding portions outside the grooves 558 and 559, the resonance characteristics hardly deteriorate.

The first and second spacer plates 556 and 557 are joined to the outside of the piezoelectric resonators 554 and 555. The spacer plates 556 and 557 are
In order not to hinder the vibration of the resonance portion of
It is composed of a U-shaped member so as to have 57a and 556a. Note that the piezoelectric resonator 531A and the piezoelectric resonators 554 and 555 are similarly joined to each other with a gap therebetween so that the respective piezoelectric vibrating portions do not come into contact with each other.

The first and second spacer plates 556, 5
57 is, for example, an insulating ceramic such as alumina,
It is made of an appropriate material such as a synthetic resin. The first and second spacer plates 556 and 557 are connected to the piezoelectric resonator 531A,
It is configured to have the same thickness as 554 and 555. That is, the resonance plate 551 is prepared as a plate-like member having a substantially uniform thickness as a whole.

First and second case substrates 552 and 553
Are each made of an insulating ceramic such as alumina or a synthetic resin. On the upper surface of the second case substrate 553, a concave portion 553a having a rectangular planar shape is formed. Although not particularly shown, a similar recess is formed on the lower surface of the first case substrate 552. Recess 553a
Is formed to provide a space below the resonance plate 552 so as not to hinder the vibration of the vibration portions of the piezoelectric resonators 531A, 554, and 555.

As shown in FIG. 67, the ladder-type filter 550 of this embodiment includes the resonance plate 551 and the first
It is obtained by bonding the second case substrates 552 and 553 with an adhesive or the like. In addition, the obtained laminated body 5
In 69, the external electrodes 570a to 570c are provided on one side,
External electrodes 570d to 570f are formed on the other side.

Therefore, in the chip type filter 550, the external electrode 570c is an input terminal, the external electrode 570b is a terminal connected to the reference potential, the external electrode 570a is an output terminal, and the external electrodes 570d to 570f are connected to each other. , it is possible to configure the T-type filter shown in FIG. 68. In the circuit of FIG. 68, two series resonators are formed by the piezoelectric resonators 554 and 555 using the slip mode, and one parallel resonator is formed by the piezoelectric resonator 531A.

By combining the chip type filter 550 with a chip type filter having a π-type connection structure described below, a three-stage ladder type filter can be formed.

Twelfth Embodiment FIGS. 69 and 70 are an exploded perspective view and an external perspective view for explaining a chip-type ladder filter according to a twelfth embodiment, respectively. This ladder-type filter has a π-type circuit configuration shown in FIG. 71. Therefore, by combining with the ladder-type filter 550 having the T-type connection structure described above, a three-stage ladder-type filter can be configured. Can be.

Referring to FIG. 69, in the chip type filter of this embodiment, first and second case substrates 572 and 573 are laminated on and under resonance plate 571. The first and second case substrates 572 and 573 have the same configuration as the above-described first and second case substrates 552 and 553. That is, the concave portion 573a is formed on the upper surface of the case substrate 573, and the concave portion is similarly formed on the lower surface of the case substrate 572.

In the resonance plate 571, a piezoelectric resonator 574 utilizing a slip mode is disposed at the center, and a third type of piezoelectric resonator 531A, 531A is connected to both sides of the piezoelectric resonator 574. ing. The piezoelectric resonator 574 has the same configuration as the piezoelectric resonator 554 using the slip mode used in the eleventh embodiment. That is, in the twelfth embodiment, the piezoelectric resonators 574 for forming the series resonators are arranged at the center, and the piezoelectric resonators 531A and 531A for forming the parallel resonators on both sides.
Are joined. Further, the piezoelectric resonator 53
First and second spacer plates 575, 576 are attached to the outside of each of 1A and 531A. The first and second spacer plates 575 and 576 have the same configuration as the first and second spacer plates 556 and 557 used in the eleventh embodiment. As described above, the piezoelectric resonator 574 is configured in the same manner as the piezoelectric resonator 554 (FIG. 66), and the same parts are denoted by the same reference numerals and description thereof will be omitted.

In the chip type filter of this embodiment, a laminate 577 shown in FIG. 70 is obtained by attaching case substrates 572 and 573 on the upper and lower sides of the resonance plate 571. External electrodes 578a to 578c and 578d to 578f are formed on both side surfaces of the stacked body 577, respectively. Thus, a chip-type ladder-type filter 579 of the twelfth embodiment is obtained.

In the ladder type filter 579, the external electrode 5
78a and the external electrode 578b are commonly connected and used as an output terminal. In addition, the external electrode 578c and the external electrode 578
d is connected to a reference potential. Then, the external electrode 578e and the external electrode 578f are commonly connected and used as an input terminal. By using as described above, it operates as a ladder-type filter having a π-type connection structure shown in FIG.

By connecting the ladder filter 550 of the eleventh embodiment and the ladder filter 579 of the twelfth embodiment, a three-stage ladder filter can be formed. That is, as shown in FIG. 72, the output terminal of the ladder-type filter 550 is connected to the ladder-type filter 5.
By connecting the input terminal of No. 79, for example,
The external electrode 570a of the ladder-type filter of the twelfth embodiment and the external electrode 57 of the ladder-type filter 579 of the twelfth embodiment.
8e, 578f, it is possible to operate as a three-stage ladder filter.

In addition, as is apparent from the first to twelfth embodiments, at least two piezoelectric resonators are stacked in the ladder-type 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 twelfth embodiments, the resonance characteristics of each piezoelectric resonator can be exhibited as desired by forming the 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 twelfth embodiments, the first piezoelectric resonator and another piezoelectric resonator as necessary 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 21 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.

Also, the electrode shape of the third type piezoelectric resonator is not limited to those shown in FIGS. For example, as shown in FIGS. 73 and 74, 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. 2, 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, the 2 m-order vibration in the bending mode in which energy is confined in the piezoelectric vibrating portion is similarly excited.

[0240]

As described above, in the ladder filter according to the present invention, at least two plate-like resonators of the series resonator and the parallel resonator are arranged in the horizontal direction, that is, in the direction parallel to the mounting surface. Since they are connected, the height of the ladder-type filter can be reduced. Further, with such a 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 type of 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 showing a relationship between a relative displacement amount and a value of n.

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 showing the appearance of a T-connection type filter prepared in the second embodiment.

FIG. 36 is a diagram showing a circuit configuration of a T-connection type filter prepared in the second embodiment.

FIG. 37 is an exploded perspective view showing a π-connection type filter prepared in the second embodiment.

FIG. 38 is a perspective view of a π connection type filter prepared in the second embodiment.

FIG. 39 is a diagram showing a circuit configuration of a π connection type filter prepared in the second embodiment.

FIG. 40 is an exploded perspective view for explaining a T-connection type filter prepared in the third embodiment.

FIG. 41 is a view showing the appearance of a T-connection type filter prepared in the third embodiment.

FIG. 42 is an exploded perspective view for explaining a T-connection type filter prepared in the third embodiment.

FIG. 43 is a perspective view for explaining a T-connection type filter prepared in the third embodiment.

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

FIG. 45 is a perspective view showing the appearance of a ladder filter according to a fourth embodiment.

FIG. 46 is a diagram illustrating a circuit configuration of a ladder-type filter according to a fourth embodiment.

FIG. 47 is an exploded perspective view for explaining a ladder-type filter according to a fifth embodiment of the present invention.

FIG. 48 is a perspective view showing the appearance of a ladder-type filter according to a fifth embodiment.

FIG. 49 is a diagram illustrating a circuit configuration of a ladder-type filter according to a fifth embodiment.

FIG. 50 is an exploded perspective view illustrating a ladder-type filter according to a sixth embodiment.

FIG. 51 is a perspective view showing the appearance of a ladder-type filter according to a sixth embodiment.

FIG. 52 is an exploded perspective view for explaining a ladder-type filter according to a seventh embodiment.

FIG. 53 is a perspective view showing the appearance of a ladder-type filter according to a seventh embodiment.

FIG. 54 is an exploded perspective view for explaining a ladder-type filter according to an eighth embodiment.

FIG. 55 is a perspective view showing the appearance of a ladder-type filter according to an eighth embodiment.

FIG. 56 is an exploded perspective view for explaining a ladder-type filter according to a ninth embodiment.

FIG. 57 is a perspective view for explaining a piezoelectric resonator used in the embodiment shown in FIG. 56;

FIG. 58 is an exploded perspective view for explaining a ladder-type filter according to a tenth embodiment.

FIG. 59 is a perspective view showing a piezoelectric plate as a model for describing a third type of piezoelectric resonator.

60 is a schematic plan view showing a state where the displacement state of the piezoelectric plate shown in FIG. 59 is analyzed by the finite element method.

FIG. 61 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. 59 is analyzed by a finite element method.

FIG. 62 is a plan view showing a charge distribution in the displaced state in FIG. 61.

FIGS. 63 (a) and (b) are diagrams showing the relationship between the Poisson's ratio σ and the ratio (b / a) and the relationship between n and the relative displacement, respectively.

FIG. 64 is a plan view showing an example of a third type of piezoelectric resonator.

FIG. 65 is a schematic plan view showing the shape of the electrode below the piezoelectric resonator shown in FIG. 64 through the piezoelectric plate.

FIG. 66 is an exploded perspective view for explaining a ladder-type filter according to an eleventh embodiment.

FIG. 67 is a perspective view showing the appearance of a ladder-type filter according to an eleventh embodiment.

FIG. 68 is a diagram illustrating a circuit configuration of a ladder-type filter according to an eleventh embodiment.

FIG. 69 is an exploded perspective view of a ladder-type filter according to a twelfth embodiment.

FIG. 70 is a perspective view showing the appearance of a ladder-type filter according to a twelfth embodiment.

FIG. 71 is a diagram showing a circuit configuration of a ladder-type filter according to a twelfth embodiment.

FIG. 72 shows a ladder filter according to an eleventh embodiment and a twelfth filter;
FIG. 6 is a plan view showing a connection state where the ladder-type filter according to the embodiment is connected.

FIG. 73 is a plan view for explaining another example of the third type of piezoelectric resonator.

FIG. 74 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 widening mode 28a: Piezoelectric ceramic plate 28b: Resonating part 28d, 28e: Supporting part 28f, 28g: Dynamic vibration absorbing part 28h, 28i: Connecting part 28j, 28k: Holding part 40: Ladder type filter 52: Piezoelectric resonator with built-in dynamic vibration absorbing part 52a ... Resonant parts 52b, 52c ... Support parts 52d, 52e ... Dynamic vibration absorbing parts 52f ... Connection parts 52g, 52h ... Holding parts 61 ... Dynamic vibration absorbing part built-in type piezoelectric resonator

──────────────────────────────────────────────────続 き 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-5-85809 145369 (JP, A) Fully open Hei 2-100335 (JP, U) Fully open Showa 60-174325 (JP, U) Fully open Showa 60-172425 (JP, U) Really open Showa 59-108330 (JP, U) Japanese Utility Model Showa 53-25245 (JP, U) Japanese Utility Model Showa 62-44525 (JP, U) Japanese Utility Model Showa 62-42328 (JP, U) Japanese Patent Publication No. Sho 53-14436 (JP, B2) Japanese Utility Model Showa 59-12811 (JP, 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 (13)

(57) [Claims] At least one series forming a series arm
A resonator and at least one parallel resonance forming a parallel arm
A ladder-type filter including at least two of the series resonators and the parallel resonators.
Are connected laterally to the mounting surface, and the at least one of the parallel resonators and the series resonators has a short side length a and a long side length pair but facing each other Ru b der
When the Poisson's ratio of the material constituting the piezoelectric vibrating part is σ, the ratio b / a of the length of the long side to the short side is expressed by the following equation. Within the range of ± 10% with respect to
Vibration Using Width Spreading Mode with Width Direction
In parts and the supporting portion that is connected to the center side of the short side of the piezoelectric vibrating unit, the coupled to the outer end of the support portion a holding portion and a pressure conductive resonator utilizing a width expansion mode with a there, ladder-type filter. 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 including at least two of the series resonators and the parallel resonators.
Are connected in the horizontal direction to the mounting surface, and the at least one of the series resonators and the parallel resonators is 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, and 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 a piezoelectric body is formed.
When the Poisson's ratio of the material is σ, the ratio b / a is 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 including at least two of the series resonators and the parallel resonators.
Are connected to the mounting surface in the lateral direction, and at least one of the series resonators and the parallel resonators has a pair of opposing rectangular surfaces and a pair of rectangular surfaces. A plate-shaped piezoelectric vibrating portion having four side surfaces connecting the first and second resonant electrodes formed on the pair of rectangular surfaces of the piezoelectric vibrating portion; and a side surface of the piezoelectric vibrating portion.
A supporting portion connected to one end of a side surface along a short side of the rectangular surface, and a holding portion connected to the supporting portion, wherein the length of the short side of the rectangular surface is a, and the length of the long side is b, when the Poisson's ratio of the material constituting the piezoelectric vibrating portion is σ, the ratio b / a is given by: Are within a range of ± 10% about a value satisfying, 2m order by using the piezoelectric transverse effect (where, m 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. Wherein said piezoelectric vibrating unit is provided between the supporting portion, the bending mode by vibrations which have reached Den
The ladder-type filter according to any one of claims 1 to 3 , further comprising a dynamic vibration absorbing unit that resonates at (5). On both sides according to claim 5, wherein said piezoelectric vibrating unit, respectively, the supporting portion and the holding portion are coupled, claims 1-4 noise
A ladder filter according to any of the claims. 6. The semiconductor device according to claim 1, further comprising first and second case substrates, wherein a structure in which at least the two resonators are connected is sandwiched between the first and second case substrates. 7. The ladder-type filter according to any one of 1 to 6 . 7. A base material, further comprising a cap material fixed on the base substrate, wherein a structure in which at least the two resonators are connected is laminated on the base substrate; The cap material is fixed to the base substrate so as to surround a plurality of resonators stacked.
The ladder-type filter according to any one of claims 1 to 6 . 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. A first and a second spacer plate connected to both sides of at least two piezoelectric resonators connected in a lateral direction so as not to hinder the vibration of the vibrating portion of each of the piezoelectric resonators. The ladder-type filter according to claim 8 , further comprising a resonance plate including at least two piezoelectric resonators and the first and second spacer plates. 10. The ladder according to claim 9 , wherein at least two piezoelectric resonators and said first and second spacer plates constituting said resonance plate are integrally formed by using the same member. Type filter. 11. The ladder-type filter according to claim 10 , wherein a plurality of the resonance plates are provided, and the plurality of resonance plates are stacked so as not to hinder each other's vibration of the piezoelectric vibrating portions. . 12. The device according to claim 11, further comprising first and second resonance electrodes provided on said piezoelectric vibrating portion, and an extraction electrode formed on said holding portion, wherein said first and second resonance electrodes are connected to said extraction electrode. 12. The electronic device according to claim 1, wherein the electrical connection is made.
A ladder filter according to any of the claims. 13. 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 2 .