JPH0490610A - Frequency adjusting method for combination piezoelectric porcelain resonators - Google Patents

Abstract

PURPOSE:To easily perform the adjustment of a resonance frequency without the deterioration of electric performance by forming the recessed part of prescribed depth while cutting the surface of a piezoelectric master substrate exposed near the part of a vibrating electrode. CONSTITUTION:After a vibrating electrode 3 formed on the surface of a piezoelectric master substrate 2 is protected by covered with a protect mask 6 composed of a metallic plate, the surface of the piezoelectric master substrate 2 exposed to the near part of this vibrating electrode 3 is cut by a sandblast method. In this way, since a recessed part 5 of the prescribed depth is formed on the surface of the piezoelectric master substrate 2 exposed to the near part of the vibrating electrode 3, the width of the substrate in these parts is thinning according to the depth of the recessed part 5. Thus, since the resonance frequency is not adjusted by adding mass on the vibrating electrode 3, the deterioration of the electric performance is not caused and the adjustment of resonance frequency can be easily performed.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a frequency adjustment method for a piezoelectric ceramic resonator chain.

<Prior Art> Conventionally, as an example of a piezoelectric ceramic resonator used for communication functional parts, acoustic parts, etc., a thickness-shear vibration resonator (hereinafter referred to as a resonator) is known as a thickness-shear vibration resonator as shown in Fig. The resonator 10 includes a rectangular piezoelectric substrate 2° with a predetermined thickness, and vibrating electrodes 3° and 53° that confine energy by facing each other are provided on each of both sides of the substrate. It is formed.

By the way, this final product, the resonator 10, is produced by manufacturing a thickness-shear vibration resonator chain (hereinafter referred to as a resonator chain) 1 as a semi-finished product, as shown in FIG. 6, in which a plurality of these resonators are formed in parallel with each other. Thereafter, it is common to separate the resonator chains 1 by cutting them. Therefore,
Based on this FIG. 6, the manufacturing procedure of the resonator chain 1 will be explained.

First, the pressure is 111M, such as lead titanate and lead zirconate titanate! By molding, sintering, and polarizing the vessel material, a piezoelectric parent substrate 2 having a size that can accommodate a plurality of resonators 10, . . . is manufactured. Then, after polishing the piezoelectric parent substrate 2 to adjust the substrate thickness, this pressure! Vibrating electrodes 3.3 are formed on each of both surfaces of the parent substrate 2 by vapor deposition or sputtering. Furthermore, by cutting the resonator chain 1 manufactured in this manner into pieces of predetermined size, the resonator 10 as a final product can be obtained.

By the way, a plurality of resonator chains 1 manufactured in this way
．． ...The resonant frequency of each piezoelectric parent substrate 2
Although the pressure will be determined depending on the thickness of the parent substrate 2. ...It is difficult to match the mutual thickness. Further, the resonator chain 1. which is determined by the polishing treatment performed before the formation of the vibrating electrode 33. ...It is very difficult to concentrate each resonant frequency within a certain required target value. Therefore, conventionally, a plurality of resonator chains 1.
As a plain text material for concentrating the resonance frequency within the target value, as shown by the imaginary line in FIG. A method is adopted in which a thermosetting resin 4.4 is applied to add mass, and the resonant frequency is lowered by this addition of mass.

<Problems to be Solved by the Invention> However, adjusting the resonant frequency by coating the thermosetting resin 4.4 on the vibrating electrode 3.3 as in the conventional example has the following disadvantages. was there. In other words, the greater the amount of adjustment of the resonant frequency required, the more the amount of thermosetting resin 44 applied must be increased, but increasing the amount of application will reduce the deterioration of electrical performance expressed by QIM etc. This naturally leads to limitations. Also, before the applied thermosetting resin 4°4 is cured, the resonator chain 1. Since it is not possible to confirm the resonant frequency of ..., it is necessary to wait for the material to harden before confirming the frequency, which requires extra effort.

The present invention has been devised in view of such conventional disadvantages, and provides a method for adjusting the frequency of a piezoelectric ceramic resonator chain that can easily adjust the resonant frequency without causing deterioration of electrical performance. is intended to provide.

Means for Solving the Problems> In order to achieve the above object, the present invention provides a method for adjusting the frequency of a piezoelectric resonator chain in which a plurality of piezoelectric resonators that are individualized by cutting are formed in parallel. There, pressure′:
J. The method is characterized in that the piezoelectric parent substrate exposed in the vicinity of the vibrating electrode formed on the surface of the parent substrate is scraped off to form a recessed portion of a predetermined depth.

<Function> According to the above method, an I-groove portion of a predetermined depth is formed by scraping off the surface of the piezoelectric parent substrate exposed in the vicinity of the vibrating electrode, so the thickness of the substrate in these portions becomes thinner, and its resonance is reduced. The frequency increases with the depth of the recess. Therefore, under the influence of the increased resonance frequency of these parts, the energy confinement effect in the part between the vibrating electrodes facing each other with the piezoelectric parent substrate in between increases, and as a result, the resonance frequency in this part increases, Its electrical performance will be improved.

<Example> Hereinafter, embodiments of the method of the present invention will be described based on the drawings.

In this embodiment, the piezoelectric ceramic resonator is a thickness-shear vibration resonator.

Fig. 1 is an external perspective view showing the schematic structure of a thickness-shear resonator (hereinafter referred to as a resonator) obtained by the method of the present invention, and Fig. 2 is a series of thickness-shear resonators as a semi-finished product (
1 is an external perspective view showing a schematic configuration of a resonator chain (hereinafter referred to as a resonator chain), and FIGS. 3 and 4 are process cross-sectional views showing a manufacturing procedure thereof. In these figures, the same reference numerals are given to the same or corresponding parts as in FIGS. 5 and 6 showing the conventional example.

The resonator 10 as a final product, as shown in FIG.
It is equipped with a piezoelectric substrate 2° in the form of a strip with a predetermined thickness,
Vibrating electrodes 3° and 3° are formed on both sides of the piezoelectric substrate, respectively, to confine energy by opposing each other with a piezoelectric substrate 2° in between. And these vibrating electrodes 3°, 3
In the vicinity of the piezoelectric substrate 2°, recesses 5° and 5° each having a predetermined depth are formed by scraping the surface of the piezoelectric substrate 2°. Further, the resonator chain 1 shown in FIG. 2 is a semi-finished product in which a plurality of resonators 10, . . . are formed in parallel.
0,... will be obtained.

Next, the manufacturing procedure of this resonator chain 1 is shown in Figures 3 and 4.
This will be explained based on the diagram.

First, a plurality of resonators 10,
A piezoelectric main board 2 is manufactured to have a size that corresponds to..., and this pressure! After a polishing process such as lapping is performed on the parent substrate 2, vibrating electrodes 3.3 are formed on each of its surfaces by vapor deposition or sputtering. As shown in FIG. 3, after the vibrating electrodes 3, 3 formed on the surface of the piezoelectric parent substrate 2 are protected by covering them with a protective mask 6.6 made of a metal plate, for example, the vibrating electrodes 3, the surface of the piezoelectric parent substrate 2 exposed in the vicinity of 3 is scraped off by sandblasting.

Then, as shown in FIG. 4, a recess 5.5 of a predetermined depth is formed on the surface of the piezoelectric parent substrate 2 exposed in the vicinity of the vibrating electrode 3.3. Therefore, the substrate thickness at these portions becomes thinner depending on the depth of the recessed portion 5.5. Furthermore, by cutting the resonator chain 1 manufactured in this way into pieces of predetermined size, the final product, the resonator 1. will be obtained.

Note that the work of scraping the surface of the piezoelectric substrate 2 can be done simultaneously on both sides, and it is possible to perform the scraping work while monitoring the resonance frequency through the protective mask 66. This has the advantage of reducing labor and ensuring reliable adjustment. Further, the work of scraping off the pressure on the mother board 2 does not have to be carried out by employing a sandblasting method; for example, a method may be adopted in which each surface of the piezoelectric substrate 2 is successively scraped off by using a grinder or the like.

By the way, in the method of this embodiment, the resonant frequency of the resonator chain 1 is adjusted by scraping off the surface of the piezoelectric parent substrate 2 exposed in the vicinity of the vibrating electrode 3.3, but the frequency according to the conventional example is It is also possible to use the adjustment method in combination.

In other words, if the adjustment of the resonant frequency by the method of this embodiment is too large and the resonant frequency of the obtained resonator chain 1 becomes too high than the required target value, the adjustment as shown by the imaginary line in FIG. As shown, mass is added by applying thermosetting resin 4.4 onto the vibrating Ti pole 3.3 of each resonator chain 1, and the resonant frequency is lowered by this addition of mass.

Further, in this embodiment, the piezoelectric ceramic resonator has been described as a thickness shear vibration resonator, but it is not limited to this, and other thickness vibration modes such as thickness longitudinal vibration and thickness torsional vibration can be used. It goes without saying that the method of the present invention can also be applied to a pressure tVA device using a reciprocal pendulum.

<Effects of the Invention> As explained above, in the method of the present invention, recesses of a predetermined depth are formed by scraping off the surface of the piezoelectric parent substrate exposed in the vicinity of the vibrating electrode, so that the substrate in these areas is The thickness becomes thinner, and the resonant frequency becomes higher depending on the depth of the recess. Therefore, as a result of the increased resonant frequency of these parts, the mechanical confinement effect in the part between the vibrating electrodes facing each other with the piezoelectric parent substrate in between increases, and the resonant frequency in this part increases. The resonant frequency will be adjusted in the direction of increasing it. In addition, at this time, as a result of the energy confinement effect being increased, electrical performance can also be improved at the same time.

That is, according to the method of the present invention, the resonant frequency is not adjusted by adding mass to the vibrating electrode.
This eliminates the possibility of deterioration in electrical performance, and provides the advantage that the resonant frequency can be adjusted easily and reliably.

[Brief explanation of drawings]

Figures 1 to 4 relate to this embodiment, where Figure 1 is an external perspective view showing a schematic configuration of a thickness-shear vibration resonator, and Figure 2 is an external perspective view showing a schematic configuration of a thickness-shear vibration resonator chain. 3 and 4 are process sectional views showing the manufacturing procedure. Furthermore, FIGS. 5 and 6 relate to conventional examples, and FIG. 5 is an external perspective view showing a schematic configuration of a thickness-shear vibration resonator, and FIG. 6 is an external perspective view showing a schematic configuration of a thickness-shear vibration resonator chain. It is a diagram. Reference numeral 1 in the figure. is the thickness-shear vibration resonator (pressure′w,
1 is a thickness-shear vibration resonator chain (piezoelectric ceramic resonator chain), 2 is a piezoelectric main substrate, 3 is a vibrating electrode, and 5 is a rich portion. Note that the same reference numerals in the figures indicate the same or corresponding parts and portions.

Claims (1)

[Claims] (1) A method for adjusting the frequency of a piezoelectric ceramic resonator chain (1) in which a plurality of piezoelectric ceramic resonators (1_0) that are individualized by cutting are formed in parallel on the surface of a piezoelectric parent substrate (2). Vibrating electrode (3)
A method for adjusting the frequency of a piezoelectric ceramic resonator chain, characterized in that a piezoelectric parent substrate (2) exposed in the vicinity of the piezoelectric substrate (2) is scraped off to form a recessed portion (5) of a predetermined depth.