JPH06112756A - Piezoelectric parts - Google Patents

Abstract

PURPOSE:To provide a production method which can easily produce the piezoelectric parts which can be applied in a higher harmonic area by suppressing the excitation of a basic ware without affecting the excitation of a tertiary higher harmonic. CONSTITUTION:A damping member 10 is applied on both sides of the exciting part of a piezoelectric resonator 2. The inner diameter D of the member 10 set at the value between the exciting area of the basic wave of the resonator 2 and the exciting area of a tertiary higher harmonic. Then the wax is applied to the D of the member 10 and the resonator 2 is covered with a resin member 3. Then the member 3 is heated and the wax is solved and absorbed by the member 3. Thus the cavities 8 are formed on both sides of the exciting part of the resonator 2 for its excitation. The excitation of the basic wave can be suppressed owing to the D set between the exciting areas of the basic wave and the tertiary higher harmonic. Then the production of the resonator 2 is facilitated since it is just required to form the member 10 to the resonator 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric component, and more particularly to a piezoelectric component utilizing the excitation frequency of the third harmonic due to thickness longitudinal vibration.

[0002]

2. Description of the Related Art A fundamental wave has a higher harmonic range (for example, 12 MHz).
When trying to obtain an excitation frequency of ~ 35 MHz),
Even if the thickness longitudinal vibration is used, the thickness becomes as thin as about 60 μm, which causes a problem of workability.

Therefore, there is known a piezoelectric component using the excitation frequency of the third harmonic by suppressing the excitation of the fundamental wave without making the thickness extremely thin. As such a piezoelectric component, for example, one in which additional mass such as solder is attached to a region where the fundamental wave is excited (Japanese Patent Laid-Open No. 3-274817) or an LC filter circuit is provided to reduce the gain of the fundamental wave. There are things.

[0004]

However, in the case where the additional mass is added, the relationship with the specific wavelength is not clear, and it is not feasible. Further, the one provided with the LC filter circuit has drawbacks that the configuration is complicated and the size is increased. Therefore, conventionally, a piezoelectric component that selectively suppresses the excitation of the fundamental wave without affecting the excitation of the third harmonic has not been realized.

Therefore, the present invention has been made in view of the above circumstances, and is intended to be applied to the harmonic region by suppressing the excitation of the fundamental wave without affecting the excitation of the third harmonic. Moreover, it is an object of the present invention to provide a piezoelectric component that is easy to manufacture.

[0006]

In order to achieve the above object, a piezoelectric component according to a first aspect of the present invention is a piezoelectric resonator and a surface of the piezoelectric resonator, the excitation area of a fundamental wave of the piezoelectric resonator. And a damping member formed outside from a region between the third harmonic excitation region and the third harmonic excitation region.

In the piezoelectric component according to the second aspect, the inner diameter of the damping member is 6 times the wavelength of the third harmonic used.
It is characterized in that it is set to 12 times.

[0008]

The operation of the piezoelectric component having the above structure will be described.

According to the piezoelectric component of the first aspect, since the excitation region of the fundamental wave of the piezoelectric resonator exists outside the excitation region of the third harmonic, the excitation region of the fundamental wave and the region of the third harmonic. The excitation of the fundamental wave can be suppressed by the damping member formed outside the region between and. Further, since the damping member is only formed on the piezoelectric resonator, it can be easily manufactured.

According to the piezoelectric component of the second aspect, the inner diameter of the damping member is set to 6 to 12 times the wavelength of the third harmonic wave to be used without affecting the excitation of the third harmonic wave. It becomes more reliable to suppress the excitation of the fundamental wave.

[0011]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of the piezoelectric component of the present invention.

The piezoelectric component 1 shown in FIG.
And a resin member 3 covering the piezoelectric resonator 2 and a damping member 10.

As shown in the plan view of FIG. 2, the piezoelectric resonator 2 includes a piezoelectric substrate 4 made of, for example, lead titanate (PbTiO ₃ ) and a pair of operations formed on the front and back surfaces of the piezoelectric substrate 4. Electrodes 5a and 5b, and auxiliary electrodes 6a and 6b, one end of which is connected to the working electrode 5 and the other end of which faces the vicinity of the lower end of the piezoelectric substrate 4, and which are attached to the auxiliary electrodes 6a and 6b by soldering or the like. Paired lead wires 7a, 7b
It has and.

The respective working electrodes 5a and 5b are arranged so as to face each other at substantially the center positions of the front and back surfaces of the piezoelectric substrate 4 with the piezoelectric substrate 4 interposed therebetween.
It has a circular shape with a predetermined diameter. Also, the working electrodes 5a, 5
b and the auxiliary electrodes 6a and 6b are formed by sputtering using a mask.

The resin member 3 is, for example, a thermosetting resin having porosity and made of a mixed resin of epoxy resin and phenol resin, and has a cavity 8 on the front and back sides of the excitation portion of the piezoelectric resonator 2. Is provided to cover the piezoelectric resonator 2 and protect the piezoelectric resonator 2.

The damping member 10 is made of an organic resin such as a photoresist agent, and is formed on the front and back surfaces of the piezoelectric resonator 1 by a resin printing method. Further, the damping member 10 is formed outside the region between the excitation region of the fundamental wave and the excitation region of the third harmonic of the piezoelectric resonator 2.
The inner diameter D is, for example, 6 to 12 times the wavelength of the third harmonic used. The excitation area of the fundamental wave of the piezoelectric resonator 2 is
Since it exists outside the excitation region of the third harmonic, the excitation of the fundamental wave can be suppressed by setting the inner diameter D between the excitation region of the fundamental wave and the region of the third harmonic. Also, by setting the inner diameter D to be 6 to 12 times the wavelength of the third harmonic to be used, it becomes more reliable to suppress the excitation of the fundamental wave without affecting the excitation of the third harmonic. Further, since the inner diameter D dimension with high accuracy is obtained by the resin printing method, the excitation of the fundamental wave can be suppressed with high accuracy.

Next, a method of manufacturing the piezoelectric component 1 of this embodiment will be described with reference to FIGS.

First, a substrate element body (not shown) made of a piezoelectric material made of lead titanate (PbTiO ₃ ) is prepared, and the front and back surfaces of this substrate element body are polished, Required number of working electrodes 5a, 5b and auxiliary electrodes 6
a and 6b are formed by sputtering or the like using a mask, and the substrate body on which the electrodes 5 and 6 are formed is cut to obtain separate piezoelectric substrates 2.

Subsequently, a pair of lead wires 7a and 7b are connected to the respective auxiliary electrodes 6a and 6b by soldering or the like to obtain the piezoelectric resonator 2 as shown in FIG.

Next, as shown in FIG. 3, the damping member 10 is applied by a resin printing method. In this case, the inside diameter D of the damping member 10 is set so as to be between the excitation region of the fundamental wave and the excitation region of the third harmonic of the piezoelectric resonator 2.

Next, as shown in FIG. 4, paraffin wax (dissolvable and removable member) 9 that can be dissolved and removed is applied to the inner diameter D side of the damping member 10.

Then, as shown in FIG. 5, the lead wires 7a and 7b are immersed in the resin member 3 by, for example, a dipping method.
Is covered with the piezoelectric resonator 2, and the resin member 3 is heated and hardened under a heating temperature (140 to 150 ° C.) and a vacuum condition. At the time of this heat curing, the wax 9 is dissolved and absorbed in the resin member 3, and the wax 9 is removed from the cavity 8 shown in FIG. 1 to obtain the piezoelectric component 1 as shown in FIG.

The frequency characteristics of the impedance of the piezoelectric component 1 thus manufactured will be described with reference to FIGS. 6 to 11.

FIGS. 6 to 11 are graphs showing frequency characteristics of the impedance Z when the inner diameter D is changed to be 6 to 12 times the wavelength (frequency 15850 kHz) λ of the third harmonic used. 6 and 7 are graphs of the fundamental wave and the third harmonic in the case of 6λ, FIGS. 8 and 9 are graphs of the fundamental wave and the third harmonic in the case of 9λ, and FIGS. 10 and 11 are respectively. 6 is a graph of a fundamental wave and a third harmonic in the case of 12λ.

As is apparent from FIGS. 6 and 7, in the case of 6λ, the impedance Z = 300Ω at the resonance point of the fundamental wave (4680 kHz) and the resonance point of the third harmonic wave (15
The result of impedance Z = 30Ω was obtained at 850 kHz). Further, as is clear from FIGS. 8 and 9,
In the case of 9λ, the impedance Z = 100Ω at the resonance point of the fundamental wave (4680 kHz), and the impedance Z = 20Ω at the resonance point of the third harmonic (15850 kHz). Further, as is clear from FIGS. 10 and 11, in the case of 12λ, the resonance point of the fundamental wave (4680)
impedance Z = 90 Ω at 3 kHz harmonics and impedance Z = at the resonance point of the third harmonic (15850 kHz).
A result of 20Ω was obtained. Thus, when the excitation frequency of the third harmonic is 15850 kHz, 6λ, 9
Impedance Z of the fundamental wave in both cases of λ and 12λ
Suppresses to 300Ω or less, impedance Z of the third harmonic
Could be 20Ω or more. Similar results can be obtained when the excitation frequency of the third harmonic is 12 MHz to 50 MHz.

Therefore, according to the piezoelectric component 1 of this embodiment,
The following effects are achieved.

(1) The excitation of the fundamental wave can be suppressed without affecting the excitation of the third harmonic, and the frequency of 12 MHz to 50 MHz can be suppressed.
It is possible to provide the piezoelectric component 1 that can oscillate stable harmonics at MHz.

(2) Excitation of the fundamental wave can be suppressed only by controlling the size of the inner diameter D of the damping member 10.
Further, since it is not necessary to provide a special additional mass or LC filter circuit only by forming the damping member 10 on the piezoelectric resonator 2, the structure is simplified and downsized, and the piezoelectric component 1 is easily manufactured. it can.

(3) The piezoelectric component 1 is not limited to the harmonic piezoelectric resonator and the harmonic piezoelectric filter, but can be widely applied to the mobile communication field using these resonators and filters, the clock generation circuit of OA equipment, and the like. .

The present invention is not limited to the above embodiment, but can be modified in various ways.

[0032]

According to the first aspect of the invention described in detail above, the fundamental wave is excited by the damping member formed outside the region between the fundamental wave excitation region and the third harmonic region. Since it suppresses only the third harmonic, it suppresses the excitation of the fundamental wave without affecting the excitation of the third harmonic, so that it can be applied to the higher harmonic range, and a piezoelectric component that is easy to manufacture is provided. be able to.

According to the second aspect of the invention, the inside diameter of the damping member is 6 to 12 of the wavelength of the third harmonic to be used.
Since it is doubled, it becomes more reliable to suppress the excitation of the fundamental wave without affecting the excitation of the third harmonic.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a piezoelectric component of the present invention.

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

FIG. 3 is a cross-sectional view showing a method of manufacturing the piezoelectric component of the present embodiment.

FIG. 4 is a cross-sectional view showing one manufacturing method of the piezoelectric component of the present embodiment.

FIG. 5 is a cross-sectional view showing one manufacturing method of the piezoelectric component of the present embodiment.

FIG. 6 is a graph showing the frequency characteristics of the impedance of the fundamental wave at 6λ of the piezoelectric component of this example.

FIG. 7 is a graph showing the frequency characteristics of the impedance of the third harmonic at 6λ of the piezoelectric component of this example.

FIG. 8 is a graph showing the frequency characteristics of the impedance of the fundamental wave at 9λ of the piezoelectric component of this example.

FIG. 9 is a graph showing the frequency characteristics of the impedance of the third harmonic at 9λ of the piezoelectric component of this example.

FIG. 10 is a graph showing the frequency characteristic of the impedance of the fundamental wave at 12λ of the piezoelectric component of this example.

FIG. 11 is a graph showing the frequency characteristics of the impedance of the third harmonic at 12λ of the piezoelectric component of this example.

[Explanation of symbols]

 1 Piezoelectric component 2 Piezoelectric resonator 10 Damping member D Inner diameter of damping member

Claims (2)

[Claims] 1. A piezoelectric resonator, and a damping formed on the surface of the piezoelectric resonator outside a region between the excitation region of a fundamental wave and the excitation region of a third harmonic of the piezoelectric resonator. A piezoelectric component having a member. 2. The piezoelectric component according to claim 1, wherein the inner diameter of the damping member is 6 to 12 times the wavelength of the third harmonic used.