JP3395665B2 - Piezo components - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric component using a piezoelectric resonator of a length vibration mode such as an oscillator.

[0002]

2. Description of the Related Art Conventionally, as a piezoelectric resonator utilizing a length vibration mode, as disclosed in Japanese Patent Application Laid-Open No. 9-162674,
The electrode provided on the front main surface of the piezoelectric ceramic substrate is divided into two by a linear groove extending in the length direction, and the divided electrodes are electrically connected by a conductive member formed in the node portion, and at the same time, on the back main surface. It is known that an entire surface electrode is provided. When mounting this piezo-resonator on the mounting substrate, the side surfaces of the piezo-resonator are opposed to the main surface of the mounting substrate, and the electrodes on the front and back main surfaces of the piezo-resonator are electrically conductive paste to the pattern electrodes on the mounting substrate It is fixed using.

When the piezoelectric resonator is mounted on the mounting substrate as described above, it is not necessary to use a metal wire to connect the whole surface electrode on the back surface side to the pattern electrode of the mounting substrate as in the conventional case, and the connecting work is easy. In addition, the area of the mounting substrate can be reduced.

[0004]

However, in the case of the above structure, since the electrodes on the front and back main surfaces of the piezoelectric resonator are fixed to the pattern electrodes on the mounting substrate by using the conductive paste, the adjacent conductive pastes are adjacent to each other. The distance between them becomes equal to or less than the thickness of the piezoelectric resonator, which may cause a short circuit between the conductive pastes. For example, in the case of a resonator in a length vibration mode with a resonance frequency of 450 kHz, its thickness is about 0.4 mm, so it is difficult to form a conductive paste in an insulating state and close to each other within this interval. On the other hand, when the piezoelectric resonator is pressed against, a short circuit easily occurs. Further, it is difficult to secure a gap between the piezoelectric resonator and the mounting substrate, and there is a risk that both ends (vibrating portions) of the piezoelectric resonator may come into contact with the mounting substrate to inhibit vibration.

Therefore, an object of the present invention is to simplify the work of connecting the main surface electrodes on the front and back of the piezoelectric resonator to the pattern electrodes of the mounting substrate, to prevent a short circuit from occurring, and to prevent the vibration of the piezoelectric resonator from being disturbed. It is to provide a piezoelectric component.

[0006]

In order to achieve the above object, the invention according to claim 1 uses a length vibration mode in which a rectangular piezoelectric substrate is provided and electrodes are formed on both main surfaces thereof. In the piezoelectric resonator and the nodes on both main surfaces of the piezoelectric resonator
First and second parts formed by applying and curing conductive paste
Of the electro-conductive support member and one main surface in the long side direction of the piezoelectric resonator .
Opposite the one side, it has a larger opening area than the side surface of the piezoelectric resonator to the main surface, or greater than the thickness of the piezoelectric resonator
Thickness of piezoelectric resonator and thickness of first and second conductive support members
An opening portion which have a smaller width than the sum of Mito is formed, and a mounting substrate on which the first and second path <br/> turn electrodes formed on both sides of the main surface of the opening Equipped with the above piezoelectric
Make sure that the above-mentioned side surface of the pendulum is located above the opening of the mounting board.
In addition, the first and second conductive support members have the first and second conductive support members.
Placed on the pattern electrodes of the
The piezoelectric resonators are connected and fixed individually with a composite material, and the main surface of the piezoelectric resonator is the main surface of the mounting substrate with respect to the mounting substrate.
Provided is a piezoelectric component which is perpendicular to a surface and in which a piezoelectric resonator is supported so as not to be in contact with the opening .

The first and second node portions are provided on both sides of the piezoelectric resonator .
The second conductive support member applies and cures the conductive paste.
Is formed by, disposed the support member so as to straddle the opening of the mounting substrate, since the connected and fixed to the pattern electrodes, the insulation distance than the thickness of the piezoelectric resonator by the openings between the pattern electrodes Secured and hard to short circuit. Moreover, since the piezoelectric resonator and the pattern electrode are connected via the supporting member, when the piezoelectric resonator is connected to the mounting substrate using a conductive adhesive or the like, the conductive adhesive or the like is used as the piezoelectric resonator. Difficult to attach to the electrode surface. Further, since the piezoelectric resonator is supported by the opening in a non-contact state with the mounting substrate, the vibration of the piezoelectric resonator is not disturbed.

Further, it is desirable that the support member is formed shorter than the width dimension of the piezoelectric resonator. In this case, the resonance frequency can be adjusted by the ratio of the width of the support member and the width of the piezoelectric resonator.

It is preferable that a cover for covering the piezoelectric resonator is fixed on the mounting substrate as described in claim 3 because the piezoelectric resonator is protected. In particular, when used as a surface mount component, since it is reflow soldered, the piezoelectric resonator can be protected by providing a cover.

[0010]

1 and 2 show an example of a piezoelectric resonator utilizing a length vibration mode according to the present invention. This resonator 1 is provided with a rectangular piezoelectric ceramic substrate 2 polarized in the thickness direction, and electrodes 3 and 4 are formed on both principal surfaces of the piezoelectric substrate 2 on almost the entire surface. Conductive support members 5 and 6 are fixed to the electrodes 3 and 4 of the resonator 1 and to the node portion (center portion in the length direction) of the resonator 1, respectively. The support members 5 and 6 are fixed to the front and back symmetrical positions of the resonator 1, and one end surface of the support members 5 and 6 has the resonator 1
Extends to the side of. Support members 5, 6 of this embodiment
Is a conductive paste applied to the electrodes 3 and 4 and cured, but solder bumps, gold bumps, or the like may be used.

In this embodiment, length L × width W × thickness T =
For a resonator 1 of 4.1 × 0.9 × 0.4 mm, length L
1 x width W1 x thickness T1 = 0.8 x 0.3 x 0.15 mm
By fixing the support members 5 and 6 of the
A piezoelectric resonator having a length vibration mode of r = 450 kHz was obtained. Note that L1 / L ≦ 0.2 is desirable in order to prevent the length vibration from being disturbed as much as possible.

As shown in FIG. 3, the resonance frequency of the resonator 1 is proportional to the ratio of the width W1 of the support members 5, 6 and the width W of the resonator 1. That is, as W1 / W approaches 1, the resonance frequency increases. Therefore, the resonance frequency can be finely adjusted by adjusting W1.
The anti-resonance frequency also changes proportionally with W1 / W, like the resonance frequency.

As a method of adjusting the width W1 of the supporting members 5 and 6, as shown by the broken line in FIG. 1, the supporting members 5 and 6 are formed to have the same width dimension as the resonator 1, and cutting with a dicer or laser is performed. The width W1 can be freely adjusted by cutting off a part by a method such as burning.

FIG. 4 shows another embodiment of the piezoelectric resonator. On one main surface of the resonator 1'of this embodiment, two electrodes 3a, which are divided by a linear groove 7 extending in the length direction,
3b is formed, and the whole surface electrode 4 is formed on the other main surface. The groove 7 is provided in order to suppress spurious due to width vibration of the resonator 1 ′ that excites length vibration. A conductive support member 5 is fixed to the node portions of the divided electrodes 3a, 3b so as to straddle the groove 7, and the divided electrodes 3a, 3
b is short-circuited. One end surface of the support member 5 is a resonator 1 '
Extends to the side of. A support member 6 (not shown) is also fixed to the node portion of the back surface electrode 4, but the width of this support member 6 does not have to be the same width W1 as the support member 5, and is larger than the width W1 of the support member 5. May be smaller.

FIGS. 5 and 6 show an example of a piezoelectric component according to the present invention, which is an example of a surface mount type oscillator using the piezoelectric resonator 1 shown in FIG. This oscillator includes a piezoelectric resonator 1 and
It is composed of a mounting substrate 10 and a cover 20.

The mounting substrate 10 is a rectangular insulating thin plate made of alumina ceramics, glass ceramics, glass epoxy resin or the like.
A concave portion (opening) 11 having an opening area larger than the side surface of the piezoelectric resonator 1 is formed. The width D of the recess 11 is
The thickness T is larger than the thickness T of the resonator 1, and the resonator 1 and the support members 5,
It is smaller than the sum of the thickness of 6 and (T + 2T1). T <D <T + 2T1

At the center of the mounting substrate 10 in the length direction, pattern electrodes 12 and 13 on the input side and the output side, which extend from both side edges of the recess 11 to the back side via the side surfaces of the mounting substrate 10, are formed by sputtering. It is formed by a known method such as vapor deposition and printing. Due to the concave portion 11, the pattern electrodes 12 and 13 are formed.
A predetermined insulation distance is secured between them.

The resonator 1 is vertically mounted so that its side surface faces the upper surface of the mounting substrate 10. That is,
The support members 5 and 6 fixed to both main surfaces of the resonator 1 are the recesses 1.
1, the lower surfaces of the supporting members 5 and 6 are in contact with the pattern electrodes 12 and 13, respectively. In this state, the supporting members 5 and 6 and the pattern electrodes 12 and 13 are connected and fixed by a conductive bonding material 14 such as a conductive adhesive or solder.

A cover 20 for covering the resonator 1 in a non-contact state is adhered on the mounting substrate 10 with an adhesive or the like to seal the periphery of the resonator 1. The cover 20 may be a resin cover or a metal cover.

Since the resonator 1 is connected to the pattern electrodes 12 and 13 via the supporting members 5 and 6 as described above, the conductive bonding material 14 does not adhere to the electrodes 3 and 4 of the resonator 1 and the resonator 1 There is no fear of disturbing the vibration of 1. Further, since the insulating distance more than the thickness of the resonator 1 can be secured between the pattern electrodes 12 and 13 by the concave portion 11, the pattern electrodes 12 and 1 can be secured.
Short circuit between 3 is unlikely to occur. In addition, the resonator 1 has a recess 11
Since it is supported by the mounting substrate 10 in a non-contact state, good vibration characteristics of the resonator 1 can be obtained.

FIG. 7 shows another example of the piezoelectric component according to the present invention. The same parts as those of the piezoelectric component shown in FIG. In the piezoelectric component of this embodiment, a through hole 15 is provided in the central portion of the mounting substrate 10 instead of the recess.
By attaching and fixing the back cover 30 to the lower surface of the mounting substrate 10,
It ensures the hermeticity.

The present invention is not limited to the above embodiment. In the piezoelectric component shown in FIGS. 5 to 7, the piezoelectric resonator 1 shown in FIG. 1 is used, but the piezoelectric resonator 1 ′ shown in FIG. 4 may be used. Also, a plurality of piezoelectric resonators may be mounted on one mounting substrate. In this case, a ladder type filter or a Colpitts type oscillation circuit can be configured by forming an appropriate pattern electrode on the mounting substrate.

[0023]

As is apparent from the above description, according to the present invention, the conductive support members fixed to the node portions on both main surfaces of the piezoelectric resonator straddle the opening of the mounting substrate to form the pattern electrode. Since they are individually connected and fixed to each other, a distance greater than the thickness of the piezoelectric resonator can be secured between the pattern electrodes by the opening, and there is no fear of short circuit. Further, since the piezoelectric resonator is supported by the opening in a non-contact state with the mounting substrate and the piezoelectric resonator is connected to the pattern electrode through the supporting member, the electrode of the piezoelectric resonator is attached with the conductive bonding material. Without wearing, there is no fear that the vibration of the resonator will be disturbed.

[Brief description of drawings]

FIG. 1 is a perspective view of an example of a piezoelectric resonator according to the present invention.

FIG. 2 is a side view of the piezoelectric resonator shown in FIG.

FIG. 3 is a diagram showing a relationship between a width dimension ratio between a support member and a piezoelectric resonator and a frequency.

FIG. 4 is a perspective view of another example of the piezoelectric resonator.

FIG. 5 is an exploded perspective view of an example of a piezoelectric component according to the present invention.

6 is a cross-sectional view of the piezoelectric component of FIG.

FIG. 7 is an exploded perspective view of another example of the piezoelectric component according to the present invention.

[Explanation of symbols] 1 Piezoelectric resonator 2 Piezoelectric substrate 3,4 electrodes 5,6 Support member 10 Mounting board 11 Recess (opening) 12, 13 pattern electrodes 20 cover

Claims (3)

(57) [Claims] 1. A piezoelectric resonator having a rectangular piezoelectric substrate and having lengthwise vibration modes in which electrodes are formed on both principal surfaces of the piezoelectric resonator, and a conductive paste is applied to the node portions of both principal surfaces of the piezoelectric resonator. ・
The first and second conductive support members formed by curing , one main surface thereof faces one side surface in the long side direction of the piezoelectric resonator, and an opening area larger than the above side surface of the piezoelectric resonator is provided on this main surface. Have
Is greater than the thickness of the piezoelectric resonator and the thickness of the piezoelectric resonator.
And less than the sum of the thicknesses of the first and second conductive support members.
With openings have a width is formed, and a first and mounting substrate to which the second pattern electrodes are formed on both sides of the main surface of the opening portion, the side surface of the piezoelectric resonator mounted Located above the board opening
So that the first and second conductive support members are
Placed on the first and second pattern electrodes respectively, and
They are individually connected and fixed by a conductive bonding material.The above-mentioned piezoelectric resonator has the main surface of the piezoelectric resonator with respect to the mounting substrate.
The piezoelectric resonator is perpendicular to the main surface of the mounting substrate and
A piezoelectric component, which is supported so as not to contact the mouth . 2. The piezoelectric component according to claim 1, wherein the first and second conductive support members are formed shorter than the width dimension of the piezoelectric resonator. 3. The piezoelectric component according to claim 1, wherein a cover covering the piezoelectric resonator is fixed on the mounting substrate.