JPH0766675A - Chip type piezoelectric resonator - Google Patents

Abstract

PURPOSE:To increase the weight of both end parts of the piezoelectric resonator and joining facing resin provided on the top and reverse surfaces, and to eliminate unnecessary vibration and reduce a spurious component by fitting vibration suppression materials to the end surfaces of both lengthwise end parts of the piezoelectric resonator. CONSTITUTION:The vibration suppression materials formed of a resin material such as an adhesive and silicone rubber, solder, or metallic plates are fitted to the end surfaces of both the lengthwise end parts of the piezoelectric resonator 31 over the facing resin on the top and reverse surfaces. When the materials of solder are used, substrate electrodes of copper, nickel, etc., are previously fitted to both the end surfaces of a laminate body 21 and then soldering is performed. The metallic plates are the same with the solder. Thus, both the end parts of the resonator 31 are increased in mass to suppress vibration of both the end parts, the thickness-shear vibration of the piezoelectric element 2 is followed up by the resin 20 to improve the suppression effect to unnecessary vibration.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip-type piezoelectric resonator utilizing energy trapping type thickness shear vibration, which is used as, for example, a chip-type filter, an oscillator, a discriminator and a trap element. .

[0002]

2. Description of the Related Art A conventional chip-type piezoelectric resonator used as a filter will be described with reference to the drawings. Figure 4
In, the piezoelectric element 2 is formed on the surface of the rectangular piezoelectric substrate 3,
A pair of terminal electrodes 4, 5 and vibrating electrodes 6, 7, 8, 9 are formed, and vibrating electrodes 13, 14 and terminal electrode 15 are formed on the back surface.
Is formed.

Of these, the terminal electrodes 4 and 5 are the piezoelectric substrate 3
Two sets of divided vibrating electrodes 6, 7 and 8, 9 are formed inside the terminal electrodes 4, 5 at both ends of the surface of
The terminal electrode 4 and the vibrating electrode 6, the terminal electrode 5 and the vibrating electrode 9, and the vibrating electrodes 7 and 8 are narrow connecting electrodes 10 and 1, respectively.
1 and 12 are connected.

On the other hand, on the back surface of the piezoelectric substrate 3, vibrating electrodes 13 and 14 are formed so as to face the vibrating electrodes 6, 7 and 8 and 9 formed on the front surface, and terminals are provided between the vibrating electrodes 13 and 14. The electrode 15 is formed. And the terminal electrode 15
Is the vibrating electrode 1 through the narrow connecting electrodes 16 and 17.
3 and 14 are connected.

With respect to the piezoelectric element 2 thus constructed,
As shown in FIG. 5, a damping material 18, 19 made of silicone rubber is provided to cover the vibrating region formed by the vibrating electrodes 6, 7, 13 and the vibrating electrodes 8, 9, 14 and the damping material 18, 19 is provided. The exterior resin 20 is provided on the front and back surfaces of the piezoelectric element 2 so as to cover the piezoelectric element 2 to form the laminated body 21. The terminal electrodes 4, 5, 15 are formed around the outer periphery of the laminated body 21 configured as described above.
The chip-type piezoelectric resonator 1 is configured by forming the external electrodes 22, 23, 24 electrically connected to the.

[0006]

Generally, in the filter using the piezoelectric element 2 of FIG. 4, in the vibration region formed by the vibrating electrodes 6, 7, 13 and the vibrating electrodes 8, 9, 14 of the piezoelectric element 2. It is ideal that energy trapping type thickness shear vibration is performed and both ends and center do not vibrate, but in reality, vibration in the vibrating region propagates slightly to both ends and center, causing unnecessary vibration and causing filter characteristics. Upper spurious components tend to occur. For this reason, in the chip-type piezoelectric resonator 1 of the above-described conventional example, although the exterior resin 20 is adhered to both ends and the center of the piezoelectric element 2 to suppress unnecessary vibration, the thickness slip of the piezoelectric element 2 Following the vibration, the exterior resin 20 on the front and back surfaces vibrates in opposite directions, so that unnecessary vibration is not sufficiently suppressed and the filter characteristics have a large amount of spurious components.

An object of the present invention is to provide a chip type piezoelectric resonator which suppresses unnecessary vibration and has excellent characteristics.

[0008]

In order to achieve the above object, in the present invention, the front and back surfaces of a rectangular piezoelectric substrate are
A plurality of vibrating electrodes for forming a vibrating region, a piezoelectric element including a plurality of terminal electrodes respectively connected to the vibrating electrode, and a damping material that covers the vibrating region of the piezoelectric element,
A chip-type piezoelectric resonator including an exterior resin covering the front and back surfaces of the piezoelectric element including the damping material, and a plurality of external electrodes electrically connected to the terminal electrodes on the side end faces in the longitudinal direction of the piezoelectric element. In the above, the vibration suppression member is attached to the end faces of both ends of the chip type piezoelectric resonator in the longitudinal direction.

[0009]

According to the above construction, by attaching the vibration suppressing material to the end faces of both ends of the piezoelectric resonator in the longitudinal direction, the mass of both ends of the piezoelectric resonator is increased, and both ends are less likely to vibrate. Therefore, unnecessary vibration can be suppressed. Also,
Since the exterior resin on the front and back surfaces is joined by the vibration suppressing material on both end surfaces, it becomes difficult to follow the thickness shear vibration of the piezoelectric element, and the vibration at both end portions is suppressed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a chip type piezoelectric resonator according to the present invention will be described below with reference to the drawings. Since the basic structure is the same as that of the conventional example, the same or corresponding parts are designated by the same reference numerals and the description thereof is omitted.

The chip-type piezoelectric resonator of the present invention is characterized in that vibration suppressing materials are attached to the end faces of both ends in the longitudinal direction. That is, as shown in FIG. 1, the piezoelectric resonator 31 is an adhesive, a resin material such as silicon rubber, solder, or solder on both end facets in the longitudinal direction and over the exterior resin 20 on the front and back surfaces. A vibration suppressing member 25 made of a metal material such as a metal plate is attached and configured. In the case of solder, the base electrodes made of copper, nickel, or the like are attached to both end surfaces of the laminated body 21 in advance, and then the solder is attached. In the case of a metal plate, it is attached with an adhesive, or like soldering, a base electrode such as copper or nickel is attached in advance and then soldering is performed. In addition, as shown in FIG. 2, the metal cap 25a is
The external electrodes 22, 23 are attached to both end surfaces of the piezoelectric resonator 32.
You may solder with.

With this configuration, the mass of both ends of the piezoelectric resonators 31 and 32 is increased, and both ends are less likely to vibrate, so unnecessary vibration is suppressed. Also, the exterior resin 2 on the front and back surfaces
Since 0 is bonded at both end surfaces by the vibration suppressing material 25, the exterior resin 20 does not vibrate following the thickness shear vibration of the piezoelectric element 2, and the effect of suppressing unnecessary vibration by the exterior resin 20 is enhanced.

As a specific example, FIG. 3 shows the filter characteristics of a bandpass filter having a center frequency of 4.5 MHz. Figure 3
In the above, the solid line represents the example of the present invention using a conductive adhesive as the vibration suppressing material, and the broken line represents the conventional example without the vibration suppressing material. From FIG. 3, 400 to 600
The peak level of spurious in the KHz band is about −30 dB with respect to the main vibrating portion in the conventional example, whereas the peak level of the present invention is about −40 dB with respect to the main vibrating portion. Therefore, an improvement of about 10 dB is recognized, and the effect of the present invention can be confirmed.

[0014]

As described above, according to the chip type piezoelectric resonator of the present invention, the vibration suppressing material is attached to the end faces of both ends of the piezoelectric resonator in the longitudinal direction. As the mass of the part increases and the exterior resin on the front and back surfaces are joined, the effect of suppressing unnecessary vibration is enhanced,
It is possible to obtain a chip-type piezoelectric resonator having excellent characteristics with less spurious components.

[Brief description of drawings]

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

FIG. 2 is a perspective view of a chip type piezoelectric resonator according to a second embodiment of the present invention.

FIG. 3 is a filter characteristic diagram in the example of the present invention.

FIG. 4 (a) is a surface view showing a piezoelectric element,
(B) is a rear view.

FIG. 5 is a perspective view of a conventional chip-type piezoelectric resonator.

[Explanation of symbols]

 2 Piezoelectric elements 18, 19 Damping material 20 Exterior resin 21 Laminated body 22-24 External electrodes 25, 25a Vibration suppressing material 31, 32 Chip type piezoelectric resonator

Claims (1)

[Claims] 1. A piezoelectric element having a plurality of vibrating electrodes for forming a vibrating region on a front surface and a back surface of a rectangular piezoelectric substrate, and a plurality of terminal electrodes respectively connected to the vibrating electrodes, and the piezoelectric element. A damping material that covers the vibration region, an exterior resin that includes the damping material and covers the front and back surfaces of the piezoelectric element, and a plurality of external electrodes that are electrically connected to the terminal electrodes at the side end surfaces in the longitudinal direction of the piezoelectric element. A chip-type piezoelectric resonator comprising: a chip-type piezoelectric resonator, wherein a vibration-suppressing material is attached to end surfaces of both ends of the chip-type piezoelectric resonator in a longitudinal direction.