JPH07147526A - Vibrator utilizing width spread mode, resonator and resonator component - Google Patents

Abstract

PURPOSE:To properly use the vibrator whose cross section is rectangular over a broad band of several hundreds kHz-2MHz, to simplify its support structure and to relax concentration of the stress by limiting a ratio b/a (b is (a) length of a long side of a rectangle and (a) is a length of a short side) of the vibrator to be a specific range. CONSTITUTION:A voltage resonator 11 has a rectangular piezoelectric resonator section 12 as a vibrator whose cross section is rectangular. The cross section of the resonator section 12 is rectangular and the section 12 has a structure of forming resonance electrodes 14, 15 on both major sides of a piezoelectric ceramic plate 13 subjected to uniform polarization processing in the broadwise direction. Support members 16, 17 are connected to the middle of the short side being a node when the resonance section 12 is excited in the width spread vibration mode. A support member 18(19) is connected to an outer end of the support member 16(17) respectively. Let the length of the short side of the resonance section 12 be (a), the length of the long side be (b), a poisson ratio of the material be o, then a ratio baa of the long side to the short side is selected to be a range satisfying b/a=n(-1,47sigma+1,88) + or -10%. When an Ac voltage is applied to terminal electrodes 20,21, the resonance section 12 is stimulated in the width spread vibration mode.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a vibrator having a rectangular cross section,
The present invention also relates to a resonator, and more particularly to a vibrating body, a resonator, and a resonance component that utilize a width expansion mode.

[0002]

2. Description of the Related Art Conventionally, a piezoelectric resonator utilizing a spreading vibration mode or a contour sliding vibration mode has been used in a band of several 10 kHz to 2 MHz.

However, in any of the above vibration modes, only the center point of the main surface of the piezoelectric resonator is the node point, and therefore it is difficult to stably hold the piezoelectric resonator. The piezoelectric resonator as described above is
Since the node point is located at the center of the main surface, a structure in which a spring terminal is used to hold the node point is used.

[0004]

However, since the conventional piezoelectric resonator utilizing the spreading vibration mode and the contour sliding vibration mode uses a plate-shaped vibrating body, it cannot be retained by a spring terminal. The stress is concentrated on the contact point between the piezoelectric resonator and the spring terminal, which may cause cracks in the piezoelectric resonator.

Further, since the node point of the vibration is located at the center of the main surface, it is difficult to select a holding structure other than the holding structure using the spring terminal, and a component using the piezoelectric resonator is difficult to select. It was difficult to miniaturize.

The object of the present invention is suitable for use in a wide frequency band of several hundreds of kHz to 2 MHz or more, and further, the supporting structure can be simplified, stress concentration is unlikely to occur, and the whole structure can be reduced. An object is to provide a vibrating body, a resonator, and a resonance component that have a high possibility of being reduced in shape.

[0007]

The present invention has been made in order to achieve the above object, and is a vibrating body having a rectangular cross section having a pair of short sides and a pair of long sides.
When the length of the short side of the rectangle is a, the length of the long side is b, and the Poisson's ratio of the material forming the vibrating body is σ, the ratio b / a of the lengths of the long side and the short side. But,

[0008]

[Equation 2]

The vibrating body is within the range of ± 10% centered on the value satisfying the above condition.

According to another specific aspect of the present invention, as in claim 2, the vibrating body having a rectangular cross section is connected to at least one of short sides of the vibrating body serving as a node point. There is provided a resonator utilizing a widening mode, further including a support member.

Further, according to another specific aspect of the present invention, a resonator using the width-spreading mode and a case substrate attached to the upper and lower sides of the resonator so as to sandwich the resonator. A widening mode is used, which comprises the case substrate or cavity forming means provided between the case substrate and the resonator in order to secure a space for preventing vibration of a vibrating portion of the resonator. Resonant components are provided.

[0012]

The vibrating body and the resonator of the present invention utilize the widening mode as described above. The width spreading mode is one of the vibration modes of a vibrating body having a rectangular cross section, as will be apparent from the examples described later, and the spreading mode vibration of a vibrating body having a square cross section and the vibration mode of a vibrating body having a rectangular cross section. It is a vibration mode that takes a vibration mode between the width mode vibration and the width mode vibration.

According to a specific aspect of the present invention, as described in claim 2, in the vibrating body utilizing the width-spreading mode, not only the center of the principal surface of the vibrating body whose vibration node point has a rectangular cross section is used. In view of the fact that it also exists in the center of the short side, the support member is connected to the center of at least one of the short sides.

Therefore, in the resonator utilizing the width-spreading mode of the present invention, the vibrating body can be supported by simply fixing the supporting member to the center of at least one short side of the vibrating body or by integrally forming the supporting member. Therefore, the support structure can be simplified. Therefore, the conventional 1-2 MHz
It is also possible to reduce the overall size as compared with the piezoelectric resonator using the contour vibration that has been commercialized in the band.

Therefore, it is possible to provide a resonator utilizing a width-spreading mode which has not existed in the past, and by devising the material of the vibrating body, it is possible to provide a resonator in a frequency band which has been difficult to obtain conventionally. can do. For example, when the vibrating body is made of a piezoelectric material, 800 kHz to 2
It is possible to obtain an energy trap type piezoelectric resonator effective in a wide frequency band of the MHz band and higher.

Further, since the supporting structure is simplified, the case substrates are fixed above and below the resonator utilizing the width-spreading mode, and the cavity forming means is provided between the case substrate or the case substrate and the resonator. With this structure, the integrated chip-type resonance component can be easily formed as described in claim 4.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be clarified by describing embodiments of the present invention with reference to the drawings.

2 to 4 are schematic plan views showing vibration modes of the vibrating body for explaining the spreading mode, the width spreading mode and the width mode. The inventor of the present application analyzed the vibration state of a rectangular plate-shaped vibrating body as a vibrating body having a rectangular cross section by changing the lengths of the short side and the long side by the finite element method. Ratio of long side length b to short side length a b / a
In the case of = 1, that is, when the vibrating body is a square plate, the vibration in the spreading vibration mode is strongly excited as shown in FIG. That is, in the vibrating body 1 having a square planar shape shown in FIG. 2, the vibration is repeated between the state indicated by the broken line A and the state indicated by the alternate long and short dash line B, and the spreading mode is strongly excited.

Further, when b / a is made considerably larger than 1, that is, when b / a >> 1, as shown in FIG. 4, the rectangular vibrating body 2 is in a state indicated by a broken line A and a dashed line. B
It was confirmed that the width mode vibration was strongly excited by vibrating between the state shown by and.

On the other hand, when the ratio = b / a is larger than 1 and is smaller than the vibration of the width mode being strongly excited, it is found that the width spreading mode shown in FIG. 3 is strongly excited. It was

Referring to FIG. 3, when the ratio b / a is selected, in the vibrating body 3 having a rectangular cross-section, the vibration between the shapes shown by the alternate long and short dash line A and the broken line B is strongly excited. Do you get it.

Since the width expansion mode is considered to be an intermediate vibration mode between the known expansion mode and the width mode, it is named as the width expansion mode as described above. Based on the above findings, a piezoelectric resonator was manufactured using a piezoelectric diaphragm whose ratio b / a was selected to be a specific value. The piezoelectric resonator thus obtained is shown in FIG. Piezoelectric resonator 5
Has a structure in which electrodes 7 and 8 are formed on the entire surfaces of both main surfaces of a piezoelectric ceramic plate 6 having a rectangular shape in cross section having a short side length a and a long side length b. Piezoelectric ceramic plate 6
Is uniformly polarized in the thickness direction as shown by an arrow P in the figure.

In the piezoelectric resonator 5, when b / a is variously changed to excite the broadening vibration mode,
It was confirmed that the above-described widening vibration mode was excited most strongly when /a=-1.47σ+1.88 was satisfied. When the displacement distribution in the piezoelectric resonator 5 in this case was analyzed by the finite element method, the result shown in FIG. 5A was obtained.

In the displacement distribution analyzed by the finite element method, as shown in FIG. 5B, the center of the principal surface of the piezoelectric resonator 5 is O, and the x-axis and the y-axis are defined as shown in the figure.
When the displacement state of each part was measured, the results shown in FIG. 6 were obtained. That is, in the piezoelectric resonator 5 in which the width-spreading mode is excited, the displacement amount is smallest at the position along the X-axis direction at the center O and X ₁ in FIG. It can be seen that the amount is the largest. This means that in the piezoelectric resonator 5 utilizing the width expansion mode, the node points are located at the center of the main surface and the center of the short side. Therefore, by supporting the center of the main surface or the center of the short side by another supporting member, it is understood that the piezoelectric resonator can be supported without hindering the above-described width expansion mode.

The ratio b / a is −1.47σ + 1.
Not only when 88 is satisfied, but also when it is an integer multiple,
It was confirmed that a similar widening mode with the node at the center of the short side was excited. This will be described with reference to FIG. FIG. 17A shows that n = 2 in the equation (1).
It is a diagram in which the displacement distribution of the vibrating body in the case of is analyzed by the finite element method, and it can be seen from the diagram that the vibration in the widening mode is similarly excited.

Further, FIG. 17B shows the displacement distribution of a resonator in which a support member is connected to the center of both short sides of the vibrating body in the case of n = 2, and a holding portion is provided outside thereof, by the finite element method. It was investigated by. As is clear from FIG. 17 (b),
The vibrating body between the support parts is excited in the widening mode,
Moreover, it can be seen that the displacement hardly propagates to the support member side.

It was also confirmed that the ratio b / a is related to the Poisson's ratio of the piezoelectric resonator 5. That is, the Poisson's ratio of the vibrating body was changed to measure the ratio b / a when the above widening vibration mode was excited, and when the value of the above b / a was plotted, the results shown in FIG. 7 were obtained. . Therefore, as shown by the straight line in FIG.

[0028]

[Equation 3]

It has been found that by selecting the above 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 expression (1), but the widening vibration mode is slightly excited even when the ratio b / a is slightly deviated from the above expression (1). Since it was found that the excitation was strong, the presence / absence of excitation in the widening vibration mode was confirmed by using a piezoelectric ceramic plate having a Poisson's ratio σ = 0.324 and changing the ratio b / a. That is, the displacement amount at the point X ₁ in FIG. 5B is D (X ₁ ), and the displacement amount at the point C (see FIG. 5) where the displacement amount is the maximum in the widening mode is D (C), and the point X relative displacement D for ₁ point C (X ₁₎ / D
(C) was measured. The results are shown in Fig. 8.

As is apparent from FIG. 8, the Poisson's ratio σ =
In the case of 0.324, it can be seen that the relative displacement is within ± 10% within the range of the ratio b / a = 1.26 to 1.54. Therefore, as described above, the ratio b / a is ± 1 from the optimum value.
A plurality of types of piezoelectric resonators 5 shown in FIG. 1 were produced so that the ratio was within 0%, and a resonance characteristic was measured by connecting a support member to the central portion of the short side. As a result, it was confirmed that when the relative displacement is within 10% as described above, the width expansion mode is well confined.

Therefore, as shown in FIG. 9, the above ratio b / a
It can be understood that the above-described widening vibration mode can be satisfactorily excited if is set within a range of ± 10% around the point satisfying the expression (1).

FIGS. 10 (a) and 10 (b) are a plan view and a front view showing a piezoelectric resonator utilizing a width expansion mode according to an embodiment of the present invention manufactured based on the above findings. The piezoelectric resonator 11 has a rectangular plate-shaped piezoelectric resonance portion 12 as a vibrating body having a rectangular cross section. The piezoelectric resonance part 12 is
The resonant electrode 1 has a rectangular cross-section and is formed on the entire surfaces of both main surfaces of the piezoelectric ceramic plate 13 that is uniformly polarized in the thickness direction.
4 and 15 are formed. Support members 16 and 17 are connected to the centers of the short sides, which are the node points when the piezoelectric resonance part 12 is excited in the wide-width vibration mode. The holding portions 18 and 19 are connected to the outer ends of the support members 16 and 17, respectively.

In this embodiment, the support members 16,
The holding portion 17 and the holding portions 18 and 19 are formed integrally with the piezoelectric ceramic plate 13. That is, it is formed by preparing a rectangular piezoelectric ceramic plate and machining it into the shape shown in FIG. Of course, the supporting members 16 and 17 and the holding portions 18 and 19 may be formed as members separate from the piezoelectric resonance portion 12, or may be connected as illustrated by an appropriate method such as bonding. Good.

The resonance electrodes 14 and 15 are the lead-out conductive portions 1 formed on one surface of the supporting members 16 and 17, respectively.
4a and 15a electrically connect to the terminal electrodes 20 and 21 formed on one main surface of the holding portions 18 and 19, respectively.

In the piezoelectric resonator 11 of the present embodiment, the piezoelectric resonator portion 12 is excited in the widening mode by applying an AC voltage from the terminal electrodes 20 and 21. in this case,
As is clear from the displacement distribution in the piezoelectric resonator 11 of the present embodiment shown in FIG. 11, the central portion of the short side of the piezoelectric resonator 12 hardly vibrates, and the central portion of the short side of the piezoelectric resonator 12 vibrates as a node. Since the points are formed, even if the support members 16 and 17 are connected to each other, the vibration in the widening mode is unlikely to be disturbed. Therefore, it is possible to effectively trap the vibration based on the widening mode between the support members 16 and 17.

Further, the size of the piezoelectric resonance part 12 is made to be 2.5 mm width × 3.5 mm length by using a piezoelectric ceramic plate.
, The resonance frequency is 800kHz, width 1.0m
Since m is 2 MHz when the length is 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 configured.

As for the resonance frequency, the effective frequency band naturally changes when the piezoelectric resonance part is made of another material. Therefore, by forming the resonance part 12 with various piezoelectric materials, it is possible to obtain the energy trap type piezoelectric resonator 11 suitable for use in various frequency bands.

FIG. 12 shows an energy trap type piezoelectric resonator according to another embodiment of the present invention. In this embodiment, the metal terminals 22 and 23 as the supporting portions are joined to the electrodes 7 and 8 on both main surfaces of the piezoelectric resonator 5 shown in FIG. 1 by soldering (not carried out) as shown in the figure. . In this case, the piezoelectric resonator 5 has the ratio b / a selected so as to strongly excite the widening mode as described above. Therefore, the piezoelectric resonator 5
Then, although the center of the short side of the main surface constitutes a node point of vibration, the metal terminals 22 and 23 are joined to the vicinity of the node point by the solder. Therefore, also in the piezoelectric resonator of this embodiment, the metal terminals 22 and 23 as the supporting members are used.
Even if they are joined as shown in the figure, the vibration of the widening mode excited in the piezoelectric resonator 5 is not easily disturbed.

FIG. 13 shows an energy trap type piezoelectric resonator according to still another embodiment of the present invention. The piezo-resonator 31 has a piezo-resonant portion 32 as a vibrating body having a rectangular cross section, as in the first embodiment. Of course, in the piezoelectric resonance part 32, a pair of resonance electrodes 32b and 32c are formed on the upper surface of the piezoelectric plate 32a so as to extend along the long side edges. The piezoelectric plate 32a is polarized in the arrow P direction shown, that is, in the direction from the resonance electrode 32b to the resonance electrode 32c. Also in this embodiment,
The ratio b / a of the length b of the long side of the piezoelectric resonance part 32 to the length a of the short side is ± 10% centered on the point satisfying the expression (1).
It is set within the range.

Therefore, by applying an AC voltage between the resonance electrodes 32b and 32c, the piezoelectric resonance part 32 vibrates in the width expansion mode. In this case, since the displacement direction of the piezoelectric resonance part 32 is parallel to the applied electric field, the piezoelectric resonance part 32 is a piezoelectric resonator utilizing the longitudinal effect.

Also in the piezoelectric resonator 31 of this embodiment, the support members 36 and 37 are connected to the node points of the vibration of the piezoelectric resonance portion 32 that resonates in the above-described widening mode.
Holding portions 38 and 39 are connected to outer end portions of the support members 36 and 37. In addition, in FIG. 13, 34a, 35a
Indicates a lead-out conductive portion, and 40 and 41 indicate terminal electrodes.

As is clear from the embodiment shown in FIG. 13, the resonator utilizing the width-spreading mode of the present invention is applicable not only to the resonator utilizing the piezoelectric lateral effect but also to the resonator utilizing the piezoelectric longitudinal effect. can do.

In the above description, the vibrating body having a rectangular cross section used in the present invention has been described by taking a piezoelectric body as an example. However, the vibrating body having a rectangular cross section as described above is used in the present invention. In the case where the ratio b / a is selected to be in a specific range, the above-described width expansion mode is excited, and in view of the fact that it is located at the node point or the center of the short side of the vibration of the width expansion mode, the support member is provided at the center of the short side. The feature is that they are connected. Therefore, the vibrating body to be used may be a vibrating body other than the piezoelectric body.

Further, in the resonator of the present invention, a dynamic vibration absorbing portion may be further provided outside the support member connected to the vibrating body so as to cancel the vibration leaked by the dynamic vibration absorbing phenomenon. Such an example is shown in FIG.

The piezoelectric resonator 42 shown in FIG. 14 corresponds to a modification of the piezoelectric resonator 11 of the first embodiment (embodiment shown in FIG. 10). Corresponding portions will be denoted by corresponding reference numerals, and the description thereof will be omitted.

In the piezoelectric resonator 42, the support members 16 and 17 are
A pair of dynamic vibration absorbing parts 43 and 44 are formed at the outer ends of the connecting members 4 at the center of the outer side surfaces of the dynamic vibration absorbing parts 43 and 44.
5, 46 are connected, and the outer ends of the connecting members 45, 46 are connected to the holding portions 18, 19. That is, compared with the piezoelectric resonator 11 shown in FIG.
It has a structure in which 3, 44 and connecting members 45, 46 are inserted. The dynamic vibration absorbing portions 43 and 44 are provided to cancel out the leaked vibration due to a known dynamic vibration absorbing phenomenon. That is, the dynamic vibration absorbing parts 43 and 44 are configured to vibrate due to the leaked vibration due to the dynamic vibration absorbing phenomenon, and thereby act to cancel the vibration leaking from the resonance part 12 side.

15 and 16 are an exploded perspective view and a perspective view for explaining a chip type resonance component according to another embodiment of the present invention. The present embodiment is configured using the piezoelectric resonator 11 utilizing the width expansion mode shown in FIG. That is, the resonance plate 53 is configured by bonding the spacers 51 and 52 having the same thickness as the piezoelectric resonator 11 to the sides of the piezoelectric resonator 11.

The spacers 51 and 52 have a substantially U-shaped planar shape, and are connected to the holding portions 18 and 19 of the piezoelectric resonator 11 at both ends and are integrated. The spacers 51 and 52 can be made of any insulating material, for example, insulating ceramics such as alumina or synthetic resin.

Rectangular frame-shaped cavity forming members 54 and 55 serving as cavity forming means are arranged above and below the resonance plate 53, and the case substrate 5 is interposed via the cavity forming members 54 and 55.
6, 57 are attached to the top and bottom of the resonance plate 53 using an insulating adhesive.

The cavity forming members 54 and 55 are the piezoelectric resonator 1
It is arranged so as not to hinder the vibration of the vibrating portion 1 of the piezoelectric resonance portion 12. Therefore, the cavity forming members 54, 5
5, the size of the openings 54a and 55a and the cavity forming member 5
The thickness of 4,55 is selected from the above viewpoint.

The cavity forming members 54 and 55 can be made of an insulating resin film such as a polyethylene terephthalate film or a sheet adhesive, but can be made of any other insulating material.

The case substrates 56 and 57 can be made of insulating ceramics such as alumina or an appropriate synthetic material such as synthetic resin.
By sandwiching and integrating the resonance plate 53 with the cavity forming members 54 and 55 by 7, the chip-type resonance component 60 shown in FIG. 16 is configured.

In the chip type resonance component 60, the external electrodes 62 and 63 are formed on both end faces of the laminated body 61 which is integrated by bonding the case substrates 56 and 57 together. The external electrodes 62 and 63 are formed by applying a conductive material by plating, vapor deposition, sputtering or the like.

Further, when the chip type resonance component 60 is mounted on a printed circuit board or the like, the external electrodes 62, 6 are provided in order to facilitate electrical connection with a conductive pattern on the circuit board.
It is preferable that 3 is formed not only on both end surfaces of the above-mentioned laminated body but also on the upper surface and the lower surface as illustrated. In order to facilitate the formation of the external electrodes 62 and 63 so as to be located also on the upper surface and the lower surface of the laminated body, in this embodiment, electrodes are previously formed on the upper surface of the case substrate 56 as shown in FIG. 56a and 56b are formed. Although not particularly shown, a pair of electrodes is similarly formed on the lower surface of the case substrate 57.

However, as described above, the electrodes 56a, 56
b may not necessarily be formed in advance, and may be formed by applying the external electrode material so as to reach the upper surface and the lower surface after obtaining the above laminated body.

Further, in this embodiment, the cavity forming member 54,
Although another member was prepared as 55, a concave portion having a planar shape corresponding to the planar shape of the opening 54a was formed on the lower surface of the case substrate 56, and similarly, the same as the opening 55a of the cavity forming member 55 was formed on the upper surface of the case substrate 57. You may form a recessed part which has a planar shape, and thereby form a cavity for not disturbing the vibration of the vibrating part of the piezoelectric resonator 11. In this case, the cavity forming member 5 is adjusted by adjusting the depth of the recess.
The use of 4,55 can be omitted.

Further, an insulating adhesive is applied to the case substrate 5 without forming the cavity forming members 54 and 55 and the concave portion as described above.
6 is applied to the lower surface of 6 and the upper surface of the case substrate 57 in a rectangular frame shape, and the thickness of the insulating adhesive is controlled to form a cavity for preventing the vibration of the resonance portion 12 of the piezoelectric resonator 11. Good. In this case, the case substrates 56 and 57
The insulative adhesive for adhering to the resonance plate 53 also serves as the cavity forming means of the present invention.

In FIGS. 15 and 16, the piezoelectric resonator 11 shown in FIG. 10 is used. However, for example, the piezoelectric resonator 31 shown in FIG. Other resonators using modes may be used, and similarly, a chip-type resonant component can be easily configured.

In the chip-type piezoelectric resonance component 60 shown in FIG. 16, the piezoelectric resonator 11 is bonded to the spacer plates 51 and 52 using an insulating adhesive (see FIG. 15).
Therefore, in the case where there is a defective adhesion at the joint portion indicated by arrow A in FIG. 15, the hermeticity is impaired. That is, the sealing property of the portion of the piezoelectric resonator 11 where the resonance portion 12 is formed is impaired. When the hermeticity is impaired, characteristics such as moisture resistance of the chip type piezoelectric resonance component deteriorate.

Next, an embodiment capable of overcoming the above moisture resistance problem will be described with reference to FIGS. FIG. 18 is an exploded perspective view for explaining a chip type piezoelectric resonance component according to still another embodiment of the present invention, and is a view corresponding to FIG. 15. In the chip-type piezoelectric resonance component shown in FIG. 18, instead of the piezoelectric resonator 11 and the spacers 51, 52 shown in FIG. 15, the piezoelectric resonator 1 having an outer shape of a rectangular plate.
11 is used. For other structures, that is, the cavity forming members 54 and 55 and the protective substrates 56 and 57,
Since it is the same as the embodiment shown in FIG. 15, the same reference numerals are given and the description is omitted by incorporating the above description.

The piezoelectric resonator 111 is composed of a piezoelectric ceramic plate 112 shown in a perspective view in FIG. That is, one rectangular piezoelectric ceramic plate is processed into a shape shown in FIG. 19 by etching with a laser or machining, for example, to obtain the piezoelectric ceramic plate 112. In the piezoelectric ceramic plate 112, a rectangular frame-shaped support portion 113 having an opening 113a and a piezoelectric ceramic plate portion 114 forming a resonance portion are integrated. Then, by forming electrodes on the piezoelectric ceramic plate 112 similarly to the piezoelectric resonator 11, the piezoelectric resonator 111 shown in FIG. 20 is obtained. Of course, the piezoelectric resonator 111 shown in FIG. 20 may be obtained by processing a substrate on which electrodes are formed in advance.

In other words, the piezoelectric resonator 111 has the same structure as that shown in FIG.
This corresponds to a structure in which the piezoelectric resonator 11 shown in 5 and the spacer plates 51 and 52 are integrated. Therefore, the piezoelectric resonator 11
Regarding the resonance part and the electrodes in FIG.
The same reference numeral as 1 is assigned, and the description thereof is omitted.

The piezoelectric resonator 111 shown in FIG. 18 is constructed by using the above-mentioned one piezoelectric ceramic plate 112. Therefore, in the embodiment shown in FIG. 15, the moisture resistance may be deteriorated by the joint portion indicated by the arrow A, whereas in the chip-type piezoelectric resonance component of the present embodiment, the above-mentioned structure is provided on the side of the resonance portion. Since such a joint does not exist, the moisture resistance is effectively enhanced.

FIG. 21 shows the piezoelectric resonator 11 shown in FIG.
1 is a perspective view of a chip-type piezoelectric resonance component obtained by laminating a cavity forming member 54, 55 and a protective substrate 56, 57. FIG. In the chip-type piezoelectric resonance component 120, external electrodes 122 and 123 are formed so as to cover a pair of end faces of a laminated body 121 obtained by bonding the above members together. Therefore, it can be surface-mounted on a printed circuit board or the like like other chip-type electronic components.

FIG. 22 shows a modification of the piezoelectric resonator 111 described above. Here, the piezoelectric resonator 131 has a rectangular frame-shaped support member 132 and a piezoelectric resonator portion 133 integrally formed with the rectangular frame-shaped support member 132. The piezoelectric resonator portion 133 has the same structure as the piezoelectric resonator 31 shown in FIG. 13 described above. Therefore, since the configuration of the resonance portion and the like is the same as that of the piezoelectric resonator 31, the same reference numerals are given and the description thereof is omitted.

Also in the piezoelectric resonator 131, since the rectangular frame-shaped support portion 132 and the piezoelectric resonator portion 133 are integrated, the piezoelectric resonator 111 shown in FIGS. 18 and 20.
Similarly, when the chip-type piezoelectric resonance component is configured, the moisture resistance of the chip-type piezoelectric resonance component can be effectively enhanced.

In the embodiments described above, the piezoelectric resonator is
One resonance part is formed using the width expansion mode. However, the present invention is also applied to a piezoelectric resonator in which a plurality of resonance parts using the width expansion mode are formed. Such an example will be described with reference to FIG. Figure 2
3 (a) and 3 (b) are a plan view of the above-described piezoelectric resonator and a schematic plan view showing the lower electrode shape through the piezoelectric ceramic plate, respectively.

The piezo-resonator 141 is for constructing a double-mode piezo-electric filter, and the first and second piezo-resonator units 142, 1 utilizing the widened vibration mode.
Has 43. The piezoelectric resonance units 142 and 143 are electrodes 142 for forming a resonance electrode on one principal surface of a rectangular piezoelectric ceramic plate portion uniformly polarized in the thickness direction.
a, 143a is formed, and electrodes 142b, 143b functioning as ground electrodes are formed on the lower surface.

The first and second piezoelectric resonance units 142, 1
Each of the vibration elements 43 is excited in the widening vibration mode, and the node points of the vibration are connected by the connecting member 144. Further, on the lower surface, the electrodes 142b and 1
43b are electrically connected to each other by a connecting conductive portion formed on the lower surface of the connecting member. Therefore, the electrode 14
2a or 143a as an input electrode or an output electrode,
By using the electrodes 142b and 143b on the lower surface as ground electrodes, a dual-mode piezoelectric filter utilizing a symmetric mode and an asymmetric mode is constructed.

The present embodiment is characterized in that the two piezoelectric resonance units 142 and 143 described above are used, and the other points are the same as those of the piezoelectric resonator 11.
That is, the first and second piezoelectric resonance units 142, 14
Each of the outer sides of 3 is connected to a rectangular frame-shaped support portion 147 via a support member. Therefore, the first and second piezoelectric resonance units 142 and 143 are arranged in the opening 147 a of the rectangular frame-shaped support portion 147.

Further, the first and second piezoelectric resonance units 142, 143 and the like arranged in these openings 147a are constructed integrally with the support portion 147. That is, an integral member having a planar shape as shown in the drawing is obtained by machining one piezoelectric ceramic plate or by etching.

FIG. 24 is a perspective view showing a piezoelectric resonator according to still another embodiment of the present invention. Piezoelectric resonator 2 of this embodiment
Reference numeral 01 is one utilizing the piezoelectric lateral effect, like the piezoelectric resonator 11 shown in FIG. However, the piezoelectric resonator 2
In No. 01, the structure of the piezoelectric resonance portion 203 configured by using the piezoelectric ceramic plate 202 having a rectangular cross section is different from that of the piezoelectric resonator 11. That is, the piezoelectric ceramic plate 202 has a direction arrow P parallel to the main surface (see FIG. 24).
Is polarized. Then, the piezoelectric ceramic plate 20
On the upper surface of No. 2, the resonance electrodes 204 and 205 are formed along the both edges 202a and 202b. Since the other structures are almost the same as those of the piezoelectric resonator 11, the description of the piezoelectric resonator 11 will be omitted by referring to the description.

As described above, since the piezoelectric ceramic plate 202 is polarized in the direction connecting the resonance electrode 204 and the resonance electrode 205, by applying an AC voltage between the resonance electrodes 204 and 205, the piezoelectric lateral effect can be obtained. A resonator utilizing a widening mode excited by is provided. Also in this embodiment, the piezoelectric ceramic plate 202 is selected such that the ratio b / a of the long side to the short side is similar to that of the embodiment shown in FIG. Therefore, FIG.
Similar to the embodiment shown in FIG. 0, a piezoelectric resonator utilizing the width expansion mode is provided and can be mechanically held by using the holding portions 206 and 207.

FIG. 25 is a perspective view showing a piezoelectric resonator according to still another embodiment of the present invention. The piezoelectric resonator 210 of this embodiment corresponds to a modification of the piezoelectric resonator 11 shown in FIG. The difference is that the piezoelectric resonator 1 shown in FIG.
In No. 1, the piezoelectric ceramic plate 13 was used, but in the piezoelectric resonator 210, a rectangular parallelepiped piezoelectric ceramic 213 having a thickness considerably larger than that of the piezoelectric ceramic plate 13 is used. That is, the piezoelectric ceramics 213 forming the piezoelectric resonance portion 212 has a rectangular cross-sectional shape whose ratio b / a is selected similarly to the embodiment shown in FIG. 10, and is parallel to the rectangular cross-section. Resonance electrode 14 on the main surface
(The resonance electrode on the other side is not shown) is formed.
Thus, in the present invention, the vibrating body having a rectangular cross section may have a rectangular parallelepiped shape having a thickness larger than the long side b of the rectangle.

FIG. 26 is a perspective view showing a structure in which a vibrating body according to still another embodiment of the present invention is held by spring terminals. The vibrating body 301 of this embodiment is configured by using a rectangular parallelepiped piezoelectric ceramic 302. The piezoelectric ceramics 302 has a rectangular parallelepiped shape having a rectangular cross section with a long side b and a short side a. In addition, the piezoelectric ceramics 3
02 is polarized in the direction indicated by arrow P, that is, in the direction parallel to the long side. In addition, the resonance electrodes 303 and 3
04 are formed on a pair of side surfaces of the piezoelectric ceramic 302 facing each other. This side surface is a side surface located on the short side.

In the vibrating body 301, the resonance electrode 30
When an AC voltage is applied from 3, 304, resonance occurs in the widening mode, and the node portion of the vibration in that case appears linearly on the side surface on the short side. That is, at half the height of the resonance electrodes 303 and 304, a vibration node appears in a linear region extending in the thickness direction of the piezoelectric ceramics 302 (direction orthogonal to the rectangular cross section).
Therefore, as shown in FIG. 26, the linear node portion can be easily mechanically held by using the spring terminals 305 and 306.

As is apparent from the vibrating body 301 shown in FIG. 26, the vibrating body of the present invention can be held by the spring terminal unlike the above-mentioned embodiments, and even in that case. In the present embodiment, since the vibration node portion appears linearly along the thickness direction of the piezoelectric ceramics 302, the stress concentration between the vibrating body 301 and the spring terminals 305 and 306 is not so large, so that the vibrating body 301 It is very unlikely that cracks will occur in the.

In each of the above-mentioned embodiments, the piezoelectric ceramic is used as the material of the vibrating body, but any material can be used as long as it exhibits piezoelectricity. For example, quartz, it may be used a polymer material of a piezoelectric single crystal and piezoelectric made of LiTaO ₃ or LiNbO _3. Further, a piezoelectric material may be formed on a semiconductor or a metal plate which itself does not exhibit piezoelectricity, and may function like the piezoelectric body.

Although the dual mode piezoelectric filter is shown in FIG. 23, the present invention can also be applied to single mode piezoelectric ceramics. Further, although all the examples show the fundamental wave in the width-spreading mode, since the center and the center of the short side similarly serve as node points even at high frequencies of triple and quintuple odd numbers, they can be used at high frequencies. it can.

[0081]

According to the present invention, in a vibrating body having a rectangular cross section, the ratio b / a between the length b of the long side and the length a of the short side of the rectangle is selected within the above specific range. Therefore, the widening mode is effectively excited. Since the vibration in the width expansion mode has a node point at the center of the short side of the rectangle, for example, by connecting the support member to the center of the short side, the width expansion by the support member is performed. It is possible to provide a resonator that can support the mode vibration without hindering it.

Accordingly, it is possible to provide a resonator utilizing a width-spreading mode which has not existed in the past, and by devising the material of the vibrating body, a resonator in a frequency band which has been difficult to obtain conventionally can be provided. can do. For example, if the vibrating body is made of piezoelectric ceramics, 800k
It is possible to provide an energy trap type piezoelectric resonator effective in a frequency band of Hz to 2 MHz or higher.

Moreover, in the resonator utilizing the width-spreading mode of the present invention, since the supporting member is connected to the center of the short side of the rectangle, the supporting structure can be simplified, and thus the conventional structure can be achieved. The overall size can be made smaller than that of a piezoelectric resonator using contour vibration that has been commercialized in the 1 to 2 MHz band.

Further, since the supporting structure can be simplified, as in the invention described in claim 4, the case substrate is attached from above and below to be laminated and integrated to easily provide a chip type resonance component. be able to.

[Brief description of drawings]

FIG. 1 is a perspective view for explaining a vibrating body used in an embodiment of the present invention.

FIG. 2 is a schematic plan view for explaining a spreading mode.

FIG. 3 is a schematic plan view for explaining a width expansion mode.

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

5A and 5B are diagrams showing a displacement distribution analyzed by a finite element method in a width expansion mode and a diagram for explaining coordinates in FIG. 5A.

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

FIG. 7 is a diagram showing a relationship between a Poisson's ratio and a dimensional ratio b / a for exciting a widening mode.

8 is a diagram showing a relationship between a ratio b / a and a relative displacement amount in the displacement distribution shown in FIG.

FIG. 9 is a diagram showing a relationship between Poisson's ratio and ratio b / a.

10 (a) and 10 (b) are a plan view and a front view showing a piezoelectric resonator utilizing a widened vibration mode according to an embodiment of the present invention.

11 is a diagram showing a displacement distribution of the piezoelectric resonator shown in FIG.

FIG. 12 is a perspective view showing a piezoelectric resonator using a width expansion mode according to another embodiment of the present invention.

FIG. 13 is a plan view showing a piezoelectric resonator using a widening mode according to still another embodiment of the present invention.

FIG. 14 is a plan view showing a piezoelectric resonator using a widening mode according to still another embodiment of the present invention, the piezoelectric resonator having a dynamic vibration absorbing portion.

FIG. 15 is an exploded perspective view of a chip-type resonant component according to an embodiment of the present invention.

FIG. 16 is a perspective view showing a chip type resonance component.

17 (a) and 17 (b) show that n = in Equation (1).
6A and 6B are diagrams showing the displacement distribution of a vibrating body and the displacement distribution of a resonator configured using the vibrating body in the case of 2.

FIG. 18 is an exploded perspective view for explaining a chip type piezoelectric resonance component using a piezoelectric resonator according to another embodiment of the present invention.

FIG. 19 is a perspective view showing a piezoelectric ceramic plate adopted in the piezoelectric resonator used in FIG.

FIG. 20 is a perspective view showing a piezoelectric resonator.

FIG. 21 is a perspective view showing the external appearance of the chip-type piezoelectric resonance component shown in FIG. 18.

FIG. 22 is a perspective view for explaining another example of the piezoelectric resonator integrated with the rectangular frame-shaped support member.

23 (a) and 23 (b) are plan views showing a piezoelectric filter as a piezoelectric resonator according to still another embodiment of the present invention and schematic diagrams showing the lower electrode shape through the piezoelectric ceramic plate. Plan view.

FIG. 24 is a perspective view showing a piezoelectric resonator according to still another embodiment of the present invention.

FIG. 25 is a perspective view showing a piezoelectric resonator according to still another embodiment of the present invention.

FIG. 26 is a perspective view showing yet another embodiment of the present invention and showing a structure in which a spring terminal of a piezoelectric resonator is held by the spring terminal.

Claims (4)

[Claims] 1. A vibrating body having a rectangular cross-sectional shape having a pair of short sides and a pair of long sides, wherein the length of the short side is a and the length of the long side is b. When the Poisson's ratio of the existing material is σ, the ratio b / a of the lengths of the long sides and the short sides is as follows. A vibrating body using a widening mode that is within ± 10% of the center. 2. A resonator utilizing a width-spreading mode, further comprising a support member connected to substantially the center of the short side of at least one of the vibrating bodies according to claim 1. 3. The resonator according to claim 2, wherein the vibrator having a rectangular cross section is a piezoelectric resonator. 4. A resonator using the width-spreading mode according to claim 2, a case substrate attached to the upper and lower sides of the resonator so as to sandwich the resonator, and a vibrating portion of the resonator. A resonance component utilizing a widening mode, comprising the case substrate or a cavity forming means provided between the case substrate and a resonator in order to secure a space for not hindering the vibration.