JP3139274B2 - Oscillator, resonator, and resonating component using width expansion mode - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a vibrating body having a rectangular cross section,
In particular, the present invention relates to a vibrating body, a resonator, and a resonance component using a widening mode.

[0002]

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

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

[0004]

However, the conventional piezoelectric resonator using the expansion vibration mode or the contour sliding vibration mode uses a plate-shaped vibrator, and therefore, when the piezoelectric resonator is held by a spring terminal. In addition, stress concentrates on the contact point between the piezoelectric resonator and the spring terminal, and there is a possibility that cracks may occur in the piezoelectric resonator.

Further, since the node point of 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 terminals, and it is difficult to select a component using the piezoelectric resonator. It was difficult to reduce the size.

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

[0007]

The first invention of the SUMMARY OF THE INVENTION The present patent application has been made in order to achieve the above object, a rectangular parallelepiped
Piezoelectric body and a plurality of resonant electrodes formed on the outer surface of the piezoelectric body.
And a pair of rectangular pairs on both sides in the polarization direction of the piezoelectric body.
When the length of the short side of the surface is a, the length of the long side is b, and the Poisson's ratio of the material forming the piezoelectric body is σ, the length of the long side and the short side is The ratio b / a of

[0008]

(Equation 3)

[0009] The as a medium mind you are in a range of ± 10%
When an AC voltage is applied between the plurality of resonance electrodes.
The width expansion mode with the short side direction as the width direction is excited
This is a vibrating body that uses a widening mode and has a resonating portion . According to a second aspect of the invention, a rectangular parallelepiped piezoelectric body is provided.
A plurality of resonance electrodes formed on an outer surface,
Extending parallel to the polarization direction of the body, the resonance electrode was formed
The length of the short side of a pair of rectangular faces facing each other, including the face
Is a, the length of the long side is b, and the piezoelectric body is constituted.
When the Poisson's ratio of the material is σ, the long side and the short side
The length ratio b / a of

(Equation 4) Within a range of ± 10% with respect to
When an AC voltage is applied between the resonance electrodes of
The resonance part where the width expansion mode with the direction
It is a vibrating body utilizing the width expansion mode.

According to a specific aspect of the present invention, as in claim 3 , the cross section is connected to a substantially center of at least one short side of the vibrating body serving as a node point of the rectangular vibrating body. A resonator utilizing a widening mode, further comprising a support member is provided.

According to another specific aspect of the present invention, there is provided a resonator using the above-mentioned width expansion mode, and a case substrate attached to the upper and lower sides of the resonator so as to sandwich the resonator. Using the width expansion mode, comprising: the case substrate or a cavity forming means provided between the case substrate and the resonator in order to secure a space for not hindering the vibration of the vibrating portion of the resonator. A resonant component is provided.

[0012]

The vibrating body and the resonator according to the present invention utilize the widening mode as described above. The width expansion mode is one of the vibration modes of a vibrating body having a rectangular cross section, as is apparent from an example described later. 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 This is a vibration mode that takes a vibration mode between the width mode vibration.

According to a specific aspect of the present invention, as set forth in claim 3 , in the vibrating body utilizing the width expansion mode, the node point of vibration is not limited to the center of the main surface of the vibrating body having a rectangular cross section. In view of the fact that the support member also exists at the center of the short side, a support member is connected to the center of at least one of the short sides.

Therefore, in the resonator using the widening mode of the present invention, the vibrating body can be supported by simply fixing the supporting member to the center of at least one of the short sides 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 to a piezoelectric resonator using a contour vibration that has been commercialized in a band.

Therefore, it is possible to provide a resonator utilizing a widening mode which has not existed conventionally, and to provide a resonator in a frequency band which has been difficult to obtain conventionally by devising a material of the vibrating body. can do. For example, when the vibrating body is made of a piezoelectric material,
An effective energy trap type piezoelectric resonator can be obtained in a wide frequency band of the MHz band and higher.

Also, since the support structure is simplified, a case substrate is fixed above and below the resonator using the above-mentioned width expansion mode, and a cavity forming means is provided between the case substrate or the case substrate and the resonator. With this configuration, an integrated chip-type resonance component can be easily configured 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.

FIGS. 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 its short side and long side by the finite element method. Ratio b / a of length b of long side to length a of short side
In the case of = 1, that is, when the vibrating body is a square plate, the vibration in the spread vibration mode is strongly excited as shown in FIG. That is, in the vibrator 1 having a square planar shape shown in FIG. 2, 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. 4, the rectangular vibrator 2 is in a state shown by a broken line A, B
It was confirmed that it vibrated between the states indicated by, and that the width mode vibration was 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, it is understood that the width expansion mode shown in FIG. 3 is strongly excited. Was.

Referring to FIG. 3, by selecting the ratio b / a, in the vibrating body 3 having a rectangular cross section, the vibration between the forms shown by the dashed line A and the broken line B is strongly excited. Do you get it.

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, a piezoelectric resonator was manufactured using a piezoelectric diaphragm in which the ratio b / a was selected to a specific value. FIG. 1 shows the piezoelectric resonator thus obtained. 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 having a rectangular shape having a short side length a and a long side length b. Piezoelectric ceramic plate 6
Are polarized uniformly in the thickness direction as shown by the arrow P in the figure.

In the piezoelectric resonator 5, when b / a was variously changed to excite the widening vibration mode,
It has been confirmed that when /a=-1.47σ+1.88 is satisfied, the widening vibration mode is most strongly excited. 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 main surface of the piezoelectric resonator 5 is defined as O, and the x-axis and y-axis are defined as shown in FIG.
When the displacement state of each part was measured, the result shown in FIG. 6 was obtained. That is, in the piezoelectric resonator 5 in which the width expansion mode is excited, the displacement amount at the position along the X-axis direction is the smallest at the center O and at X ₁ in FIG. It can be seen that the amount is largest. This means that in the piezoelectric resonator 5 using the width expansion 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 can be supported without obstructing the width expansion mode.

The ratio b / a is -1.47σ + 1.
Not only when it satisfies 88, but also when it is an integral multiple of it,
It has been confirmed that a similar widening mode in which the center of the short side becomes the node point is excited. This will be described with reference to FIG. FIG. 17A shows that n = 2 in equation (1).
FIG. 6 is a diagram in which the displacement distribution of the vibrating body in the case of (1) is analyzed by the finite element method, and it can be seen from the figure that the vibration in the width-extending mode is similarly excited.

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

Further, it was confirmed that the ratio b / a was related to the Poisson's ratio of the piezoelectric resonator 5. That is, by changing the Poisson's ratio of the vibrating body and measuring the ratio b / a when the above-mentioned widening vibration mode is excited, and plotting the value of b / a, the result shown in FIG. 7 was obtained. . Therefore, as shown by the straight line in FIG.

[0028]

(Equation 5)

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 (1), but the widening vibration mode is not excited even when the ratio b / a slightly deviates from the above equation (1). 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 amount at point X ₁ in FIG. 5B is D (X ₁ ), and the displacement amount at point C (see FIG. 5) where the displacement amount is the largest in the width expansion mode is D (C). Relative displacement D (X ₁ ) / D of point ₁ to point C
(C) was measured. The results are shown in FIG.

As is clear 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% if the ratio b / a is within the range of 1.26 to 1.54. Therefore, as described above, the ratio b / a is ± 1 from the optimum value.
A plurality of types of the piezoelectric resonators 5 shown in FIG. 1 were manufactured so as to be within 0%, and a supporting member was connected to the center of the short side to measure resonance characteristics. As a result, it was confirmed that when the relative displacement was within 10% as described above, the widening mode was well confined.

Therefore, as shown in FIG.
Is set within a range of ± 10% around a point satisfying the expression (1), it can be understood that the above-mentioned widening vibration mode can be favorably excited.

FIGS. 10 (a) and 10 (b) are a plan view and a front view showing a piezoelectric resonator using a widening 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 resonator 12 as a vibrating body having a rectangular cross section. The piezoelectric resonance section 12
The resonance electrode 1 has a rectangular cross-section and is formed over the entire main surfaces of the piezoelectric ceramic plate 13 uniformly polarized in the thickness direction.
4, 15 are formed. Support members 16 and 17 are connected to the center of the short side, which is a node point when the piezoelectric resonance unit 12 is excited in the widening 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 and
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 to have the shape shown in FIG. However, the support members 16 and 17 and the holding portions 18 and 19 may be formed of members separate from the piezoelectric resonance portion 12, and may be connected as shown by an appropriate method such as adhesion. Good.

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

In the piezoelectric resonator 11 of this embodiment, by applying an AC voltage from the terminal electrodes 20 and 21, the piezoelectric resonator 12 is excited in the widening mode. in this case,
As is clear from the displacement distribution in the piezoelectric resonator 11 of the present embodiment shown in FIG. 11, the center of the short side of the piezoelectric resonator 12 hardly vibrates, and the center of the short side of the piezoelectric resonator 12 is the vibration node. Since the points are formed, even in the case where the support members 16 and 17 are connected, the vibration in the width expansion mode is not easily disturbed. Therefore, the vibration based on the above-mentioned width expansion mode can be effectively confined between the support members 16 and 17.

The size of the piezoelectric resonance portion 12 is set to be 2.5 mm wide × 3.5 mm long by using a piezoelectric ceramic plate.
, The resonance frequency is 800 kHz and the width is 1.0 m
Since the frequency is 2 MHz when m × 1.4 mm in length, 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 resonance section 12 from 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, metal terminals 22 and 23 as supporting portions are joined to the electrodes 7 and 8 on both main surfaces of the piezoelectric resonator 5 shown in FIG. 1 by solder (not shown) as shown in the figure. . In this case, the ratio b / a of the piezoelectric resonator 5 is selected so that the width expansion mode can be strongly excited as described above. Therefore, the piezoelectric resonator 5
In this example, the center of the short side of the main surface forms a vibration node point, and 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 the present embodiment, the metal terminals 22 and 23 as support members are provided.
Are joined as shown in the figure, the vibration of the width expansion 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 piezoelectric resonator 31 has a piezoelectric resonator 32 as a vibrator having a rectangular cross section, as in the first embodiment. However, in the piezoelectric resonance portion 32, a pair of resonance electrodes 32b and 32c are formed on the upper surface of the piezoelectric plate 32a along the long side edge. The piezoelectric plate 32a is polarized in the direction indicated by arrow P in the figure, 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 portion 32 to the length a of the short side is ± 10% around a point satisfying the expression (1).
It is set within the range.

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

Further, also in the piezoelectric resonator 31 of the present embodiment, the supporting members 36 and 37 are connected to the nodes of the vibration of the piezoelectric resonance section 32 which resonates in the above-mentioned widening mode.
Holders 38 and 39 are connected to outer ends of the support members 36 and 37. In FIG. 13, 34a, 35a
Indicates a lead conductive portion, and reference numerals 40 and 41 indicate terminal electrodes.

As is clear from the embodiment shown in FIG. 13, the resonator using the widening mode of the present invention is applicable not only to the one utilizing the piezoelectric transverse effect but also to the one utilizing the piezoelectric longitudinal effect. can do.

In the above description, the vibrator having a rectangular cross section used in the present invention has been described as an example of a vibrator having a rectangular cross section. By selecting the ratio b / a in a specific range in the above, the width expansion mode described above is excited, and in view of being located at the node point or the center of the short side of the vibration of the width expansion mode, the supporting member is provided at the center of the short side. Are connected to each other. Therefore, a vibrating body other than the piezoelectric body may be used as the vibrating body.

Further, in the resonator of the present invention, a dynamic vibration absorbing portion may be further provided outside the supporting member connected to the vibrating body, so as to cancel the vibration leaked due to 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 (the embodiment shown in FIG. 10). The corresponding parts are given the same reference numerals, and the description thereof will be omitted.

In the piezoelectric resonator 42, the support members 16, 17
A pair of dynamic vibration absorbing portions 43 and 44 are formed at the outer ends of the connecting member 4.
5 and 46 are connected, and the outer ends of the connecting members 45 and 46 are connected to the holding portions 18 and 19. That is, as compared with the piezoelectric resonator 11 shown in FIG.
3 and 44 and connecting members 45 and 46 are inserted. The dynamic vibration absorbing portions 43 and 44 are provided to cancel the leaked vibration by a known dynamic vibration absorbing phenomenon. That is, the dynamic vibration absorbing portions 43 and 44 are configured to vibrate in response to the leaked vibration due to the dynamic vibration absorbing phenomenon, thereby acting to cancel the vibration leaked from the resonance portion 12 side.

FIGS. 15 and 16 are an exploded perspective view and a perspective view for explaining a chip-type resonant component according to another embodiment of the present invention. This embodiment is configured by using the piezoelectric resonator 11 using the widening mode shown in FIG. That is, by attaching the spacers 51 and 52 having the same thickness as the piezoelectric resonator 11 to the side of the piezoelectric resonator 11, the resonance plate 53 is formed.

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

Above and below the resonance plate 53, rectangular frame-shaped cavity forming members 54 and 55 as cavity forming means are arranged, and the case substrate 5 is interposed via the cavity forming members 54 and 55.
6 and 57 are bonded to the upper and lower sides of the resonance plate 53 using an insulating adhesive.

The cavity forming members 54 and 55 are provided with the piezoelectric resonator 1.
It is arranged so as not to hinder the vibration of the first vibrating portion, that is, the piezoelectric resonance portion 12. Therefore, the cavity forming members 54, 5
5, the size of the openings 54a, 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 formed of an insulating resin film, for example, a polyethylene terephthalate film or a sheet adhesive, but can be formed of any other insulating material.

The case substrates 56 and 57 can be made of an insulating ceramic such as alumina or a suitable synthetic material such as a synthetic resin.
The chip-type resonance component 60 shown in FIG. 16 is configured by sandwiching the resonance plate 53 via the cavity forming members 54 and 55 and integrating them with each other.

In the chip-type resonance component 60, external electrodes 62 and 63 are formed on both end surfaces of a laminated body 61 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 mounting the chip-type resonant component 60 on a printed circuit board or the like, external electrodes 62 and 6 are provided to facilitate electrical connection with conductive patterns on the circuit board.
3 is preferably formed not only on both end faces of the laminate, but also on the upper and lower faces as shown. In order to facilitate the formation of the external electrodes 62 and 63 so as to be located also on the upper and lower surfaces of the laminate, in this embodiment, 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 and lower surfaces after obtaining the laminate.

In this embodiment, the cavity forming member 54,
Although a separate 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 the same as the opening 55a of the cavity forming member 55 was similarly formed on the upper surface of the case substrate 57. A concave portion having a planar shape may be formed, thereby forming a cavity for preventing the vibration of the vibrating portion 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, the insulating adhesive is applied to the case substrate 5 without forming the cavity forming members 54 and 55 and the concave portions as described above.
6 is applied to the lower surface of the substrate 6 and the upper surface of the case substrate 57 in a rectangular frame shape, and by controlling the thickness of the insulating adhesive, a cavity is formed to prevent the vibration of the resonance portion 12 of the piezoelectric resonator 11. Is also good. In this case, the case substrates 56 and 57
The insulating 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. Another resonator using a mode may be used, and similarly, a chip-type resonance 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 a bonding failure occurs at the joint indicated by the arrow A in FIG. 15, the sealing performance is impaired. That is, the sealing performance of the portion of the piezoelectric resonator 11 where the resonance section 12 is formed is impaired. When the sealing property is impaired, characteristics such as moisture resistance of the chip-type piezoelectric resonance component deteriorate.

Next, an embodiment capable of overcoming the above problem of moisture resistance 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 diagram corresponding to FIG. In the chip-type piezoelectric resonance component shown in FIG. 18, a piezoelectric resonator 1 having a rectangular plate shape is used instead of the piezoelectric resonator 11 and the spacers 51 and 52 shown in FIG.
11 is used. For other structures, that is, the cavity forming members 54 and 55 and the protection substrates 56 and 57,
Since this embodiment is the same as the embodiment shown in FIG. 15, the same reference numerals are given and the description is omitted by using the above description.

The piezoelectric resonator 111 is constituted by using a piezoelectric ceramic plate 112 shown in a perspective view in FIG. That is, one rectangular piezoelectric ceramic plate is processed into the shape shown in FIG. 19 by, for example, laser etching or mechanical processing, thereby obtaining 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 constituting a resonance portion are integrated. Then, by forming electrodes on the piezoelectric ceramic plate 112 in the same manner as the piezoelectric resonator 11, the piezoelectric resonator 111 shown in FIG. 20 is obtained. Of course, the substrate on which the electrodes are formed in advance may be processed to obtain the piezoelectric resonator 111 shown in FIG.

In other words, the piezoelectric resonator 111 corresponds to FIG.
5 corresponds to a structure in which the piezoelectric resonator 11 and the spacer plates 51 and 52 are integrated. Therefore, the piezoelectric resonator 11
1, the resonance unit and the electrodes
The same reference numerals as in 1 denote the same parts, and a description thereof will be omitted.

The piezoelectric resonator 111 shown in FIG. 18 is constituted by using one piezoelectric ceramic plate 112 described above. Therefore, in the embodiment shown in FIG. 15, the moisture resistance may be deteriorated by the joint indicated by the arrow A, whereas in the chip-type piezoelectric resonance component of this embodiment, the above-mentioned Since such a joint does not exist, the moisture resistance is effectively improved.

FIG. 21 shows the piezoelectric resonator 11 shown in FIG.
1 is a perspective view of the resulting chip-type piezoelectric resonance component by stacking a cavity forming member 54, 55 and the protective substrate 56. In the chip-type piezoelectric resonance component 120, external electrodes 122 and 123 are formed so as to cover a pair of end surfaces of the laminated body 121 obtained by bonding the above members. 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 configuration as the piezoelectric resonator 31 shown in FIG. 13 described above. Therefore, since the configuration of the resonance unit and the like is the same as that of the piezoelectric resonator 31, the same reference numerals are given and the description thereof will be 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.
Similarly to the above, when a chip-type piezoelectric resonance component is configured, the moisture resistance of the chip-type piezoelectric resonance component can be effectively improved.

In the embodiment described above, the piezoelectric resonator has:
One resonance portion utilizing the width expansion mode is formed. However, the present invention is also applied to a piezoelectric resonator in which a plurality of resonating portions using the widening mode are formed. Such an example will be described with reference to FIG. FIG.
3A and 3B are a plan view of the above-described piezoelectric resonator and a schematic plan view showing a lower electrode shape through a piezoelectric ceramic plate, respectively.

The piezoelectric resonator 141 constitutes a double mode piezoelectric filter, and includes first and second piezoelectric resonator units 142, 1 utilizing a widening vibration mode.
43. The piezoelectric resonance units 142 and 143 are provided with electrodes 142 for forming resonance electrodes on one main surface of a rectangular piezoelectric ceramic plate portion uniformly polarized in the thickness direction.
a, 143a, and electrodes 142b, 143b functioning as ground electrodes on the lower surface.

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

The present embodiment is characterized in that the two piezoelectric resonance units 142 and 143 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 and 14
On the outside of the support member 3, each 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 147a of the rectangular frame-shaped support portion 147.

The first and second piezoelectric resonance units 142, 143 and the like disposed in the opening 147a are integrally formed with the support portion 147. That is, an integral member having a planar shape as shown in the figure is obtained by machining or etching one piezoelectric ceramic plate.

FIG. 24 is a perspective view showing a piezoelectric resonator according to still another embodiment of the present invention. Piezoelectric resonator 2 of the present embodiment
01 utilizes the piezoelectric lateral effect, similarly to the piezoelectric resonator 11 shown in FIG. However, the piezoelectric resonator 2
In FIG. 01, the structure of the piezoelectric resonator 203 formed by using a 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
2 has a structure in which resonance electrodes 204 and 205 are formed along both edges 202a and 202b. The other structure is almost the same as that of the piezoelectric resonator 11, and thus the description of the piezoelectric resonator 11 is omitted here.

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, 205, the piezoelectric transverse effect is obtained. And a resonator utilizing the width expansion mode excited by the above. Also in this embodiment, in the piezoelectric ceramic plate 202, the ratio b / a of the long side to the short side is selected in the same relationship as the embodiment shown in FIG. Therefore, FIG.
Similarly to the embodiment shown in FIG. 0, a piezoelectric resonator utilizing the widening mode is provided, and can be mechanically held using the holding units 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.
1 uses the piezoelectric ceramic plate 13, but the piezoelectric resonator 210 uses a rectangular parallelepiped piezoelectric ceramics 213 that is considerably thicker than the piezoelectric ceramic plate 13. That is, the piezoelectric ceramics 213 constituting the piezoelectric resonance portion 212 has a rectangular cross-sectional shape whose ratio b / a is selected in the same manner as the embodiment shown in FIG. 10, and is parallel to the rectangular cross-section. Resonant electrode 14 on main surface
(The other side of the resonance electrode 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 using a rectangular parallelepiped piezoelectric ceramic 302. The piezoelectric ceramic 302 has a rectangular parallelepiped shape having a rectangular cross section with a long side of b and a short side of a. In addition, piezoelectric ceramics 3
02 is polarized in the direction of arrow P shown in the figure, that is, in the direction parallel to the long side. Also, the resonance electrodes 303 and 3
04 is formed on a pair of opposing side surfaces of the piezoelectric ceramic 302. This side surface is a side surface located on the short side.

In the vibrating body 301, the resonance electrode 30
By applying an AC voltage from 3, 304, resonance occurs in the width expansion mode, and the node part of the vibration in that case appears linearly on the short side surface. That is, at a half height position of the resonance electrodes 303 and 304, a vibration node portion appears in a linear region extending in the thickness direction of the piezoelectric ceramic 302 (a 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 clear from the vibrating body 301 shown in FIG. 26, the vibrating body of the present invention can be held by a spring terminal unlike the above-described embodiments, and even in this case, In this embodiment, since the node part of the vibration appears linearly along the thickness direction of the piezoelectric ceramic 302, the stress concentration between the vibrating body 301 and the spring terminals 305 and 306 is not so large. There is very little possibility that cracks will occur in the surface.

In each of the embodiments described above, the piezoelectric ceramic is used as the material of the vibrating body. However, any material can be used as long as the material 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. Alternatively, a piezoelectric material may be formed on a semiconductor or metal plate which does not itself exhibit piezoelectricity, and may function in the same manner as the piezoelectric body.

FIG. 23 shows a dual mode piezoelectric filter, but the present invention can be applied to a single mode piezoelectric ceramic. Further, in each of the embodiments, the fundamental wave in the width-spreading mode has been shown. However, the center and the center of the short side become the node points at the third and fifth odd high frequencies as well, so that it can be used at a high frequency. it can.

[0081]

According to the present invention, in the 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-mentioned 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 as described in claim 3 , the width expansion is performed by the support member. It is possible to provide a resonator that can support the mode vibration without hindering the mode vibration.

Therefore, it is possible to provide a resonator utilizing a width expansion mode which has not existed conventionally, and to provide a resonator in a frequency band which has been difficult to obtain conventionally by devising a material of the vibrating body. can do. For example, the case where the vibrator a piezoelectric ceramics, 800k
It is possible to provide an energy trapping type piezoelectric resonator that is effective in a frequency band of Hz to 2 MHz or higher.

Moreover, in the resonator using the widening 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. The overall size can be reduced as compared with a piezoelectric resonator utilizing contour vibration that has been commercialized in the 1-2 MHz band.

Further, in order to simplify the supporting structure, a chip-type resonant component is easily provided by laminating and integrating case substrates from above and below as in the invention according to claim 4. be able to.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating 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.

FIGS. 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;

FIG. 6 is a diagram showing a relationship between a position along the x direction and a displacement amount in the displacement distribution shown in FIG. 5;

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

FIG. 8 is a view showing a relationship between a ratio b / a and a relative displacement amount in the displacement distribution shown in FIG. 5;

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

FIGS. 10A and 10B are a plan view and a front view showing a piezoelectric resonator using a widening 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 widening 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, and showing a piezoelectric resonator having a dynamic vibration absorber.

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

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

FIGS. 17 (a) and (b) show the case where n =
FIG. 4 is a diagram showing a displacement distribution of a vibrating body and a displacement distribution of a resonator configured using the vibrating body in the case of No. 2;

FIG. 18 is an exploded perspective view illustrating 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 used in the piezoelectric resonator used in FIG. 18;

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

FIG. 21 is an exemplary perspective view showing the appearance of the chip-type piezoelectric resonance component shown in FIG. 18;

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

FIGS. 23A and 23B are a plan view showing a piezoelectric filter as a piezoelectric resonator according to still another embodiment of the present invention and a schematic diagram showing a lower electrode shape through a 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 still another embodiment of the present invention, showing a structure in which a piezoelectric terminal is held by a spring terminal of a piezoelectric resonator.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H03H 9/00-9/215

Claims (4)

(57) [Claims] 1. A rectangular parallelepiped piezoelectric body and an outer surface of the piezoelectric body
A plurality of resonance electrodes formed, wherein the polarization of the piezoelectric body
When the length of the short side of a pair of rectangular surfaces on both sides in the direction is a, the length of the long side is b, and the Poisson ratio of the material forming the piezoelectric body is σ, the long side and the short side are short. Side / length ratio b /
a is It is within a range of ± 10% around a plurality
When an AC voltage is applied between the resonance electrodes of
The resonance part where the width expansion mode with the direction
A vibrating body using a width expansion mode. 2. A rectangular parallelepiped piezoelectric body and an outer surface of the piezoelectric body
A plurality of resonance electrodes formed, wherein the polarization of the piezoelectric body
Extending parallel to the direction, including the surface on which the resonance electrode is formed.
The length of the short side of a pair of rectangular surfaces facing each other is a,
The length of the long side is defined as b, and the material constituting the piezoelectric body is
When the Poisson's ratio is σ, the length of the long side and the short side
The ratio b / a of, [number 2] Within a range of ± 10% with respect to
When an AC voltage is applied between the resonance electrodes of
The resonance part where the width expansion mode with the direction
A vibrating body using a width expansion mode. 3. The method of claim 1, 2 further comprising at least one of the support member connected to the short side substantially center of the vibrating body according to, resonator utilizing a width expansion mode. 4. A resonator using the widening mode according to claim 3 , a case substrate attached to upper and lower sides of the resonator so as to sandwich the resonator, and a vibrating portion of the resonator. And a cavity forming means provided between the case substrate or the case substrate and the resonator in order to secure a space that does not hinder the vibration of the resonator.