JPH02198210A - Manufacture of piezoelectric component - Google Patents

Abstract

PURPOSE:To reduce the dispersion in the characteristic by preventing silver corrosion of a vibration electrode without direct abutting of a tip to the vibration electrode when an element is fixed tentatively to a tip of an auxiliary terminal together with a lead terminal and even when the tip of the auxiliary terminal is approached to the vibration electrode. CONSTITUTION:Lead terminals 10, 11 and a piezoelectric element 20 are soldered by soldering the tip of the lead terminal to an external connection electrode while hot air whose temperature is regulated over the entire surrounding of the piezoelectric element from a nozzle is jetted by the so-called hot air method in the state of the piezoelectric element fixed tentatively to the tip of each terminal and heating the entire of each terminal and the piezoelectric element. Then wax for forming cavity is dropped around the piezoelectric element as required. In this case, since projections 6, 7 regulate the adhering region of the wax, cavities 8, 9 whose diameter is uniform are formed when resin packaging is applied with a mold resin 15. Thus, the piezoelectric component with excellent damping and spurious characteristic is easily obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Al Industrial Field of Application) This invention relates to a method of manufacturing a piezoelectric component in which lead terminals are connected to a piezoelectric element.

(bl) Prior Art The manufacturing process of piezoelectric components such as ceramic filters is broadly divided into the process of manufacturing the piezoelectric element, and the process of attaching lead terminals to the piezoelectric element and applying a resin exterior.

An example of a conventional method for attaching lead terminals to a piezoelectric element is shown in FIG. In the figure, reference numeral 20 denotes a piezoelectric element, and two vibrating electrodes 2.degree. 3 are formed approximately at the center of both main surfaces of the strip-shaped piezoelectric substrate 1, facing each other with the piezoelectric substrate interposed therebetween. Furthermore, external connection electrodes 4.5 are formed at the ends of both main surfaces of the piezoelectric substrate 1, and are continuous to the vibrating electrodes. Also, in the figure io, it
is a lead terminal, and 12.13 is an auxiliary terminal. When attaching lead terminals to a piezoelectric element having two external connection electrodes as in this example, it is sufficient to attach two lead terminals in the end, but for convenience of automatic production, auxiliary terminals 12.
There are 13. That is, even if an attempt was made to temporarily fix the piezoelectric element 20 using only the two lead terminals 10.11 before soldering the lead terminals, a couple of forces would be applied to the piezoelectric element 20 because the external connection electrodes 4.5 are far apart. Therefore, the piezoelectric element 20 cannot be temporarily fixed. Therefore, auxiliary terminals 12 and 13 are arranged to assist in temporary fixing in addition to the terminals for electrical connection, and temporary fixing is made possible by sandwiching the piezoelectric element 20 between the tips of these terminals. .

Note that the lead terminals 10.11 are solder-plated in advance, and after the piezoelectric element is temporarily fixed, reflow soldering is performed to attach the lead terminals 10.11 to the external connection electrodes 45 of the piezoelectric element.
The tip of No. 11 is soldered.

(C) Problems to be Solved by the Invention However, in the conventional manufacturing method of piezoelectric components in which lead terminals are attached to piezoelectric elements using auxiliary terminals, there are technical problems to be solved as described below. .

Lead terminals 10.11 and auxiliary terminals 12. shown in FIG.
Since all of the terminals 13 are formed integrally with a hoop material protruding from the strip, all the terminals are solder-plated by the solder dip method or the like during the solder plating described above. Therefore, in the example shown in FIG. 5, if reflow soldering is performed with the auxiliary terminal 12 in contact with the vibrating electrode 2, the silver electrode constituting the vibrating electrode will be at the tip of the lead terminal 12. So-called silver (leaching) that leaks into the solder
I wake up. As a result, predetermined characteristics as a piezoelectric component cannot be obtained, resulting in a defective product.

Note that even if the positioning accuracy of the piezoelectric element to the tip of each lead terminal is improved during temporary fixing, there is a risk that the tip of the auxiliary terminal may come into contact with a vibrating electrode or the like due to slight movement of the piezoelectric element during reflow soldering. Furthermore, if the extreme ends of the piezoelectric element are held between the ends of the auxiliary terminal so that they do not come into contact with the vibrating electrode even if they are misaligned, reliable temporary fixation is impossible.

An object of the present invention is to provide a method for manufacturing a piezoelectric component that allows soldering 4 without bringing the auxiliary terminal tip into contact with the vibrating electrode even if there is some misalignment between the tip of each terminal and the piezoelectric element. Particularly td) Means for Solving the Problems The method for manufacturing a piezoelectric component of the present invention includes printing and forming a frame-shaped protrusion on the surface of a piezoelectric element and around a vibrating electrode, and at least the tips of a lead terminal and an auxiliary terminal. After the piezoelectric element is temporarily fixed between the tip of the lead terminal and the auxiliary terminal by solder plating, the tip of the lead terminal and the external connection electrode of the piezoelectric element are soldered by heating.

(e) Function In the piezoelectric component manufacturing method of the present invention, a frame-shaped protrusion is printed on the surface of the piezoelectric element and around the vibrating electrode. Therefore, even if the piezoelectric element is temporarily fixed between the lead terminal and the auxiliary terminal tip and the auxiliary terminal tip comes close to the vibrating electrode, the auxiliary auxiliary terminal tip will not be formed around the vibrating electrode. ≠It comes into contact with the half-frame-shaped protrusion and does not come into direct contact with the vibrating electrode. Therefore, by performing reflow soldering in this state, the tip of the lead terminal can be soldered to the external connection electrode of the piezoelectric element without causing the vibrating electrode to be damaged by the auxiliary terminal.

(f) Example First, FIG. 2 shows a front view of a piezoelectric element to which the present invention is applied. In the figure, 1 is a rectangular piezoelectric substrate. A vibrating electrode 2 is formed at the center of the first main surface (paper side) of this piezoelectric base Fi,1, and an electrode 4 for external connection of this vibrating electrode 2 is formed at the end. The other vibrating electrode 3 facing the vibrating electrode 2 via the piezoelectric substrate is formed at the center of the second main surface (back side) of the piezoelectric substrate 1, and an electrode for external connection of the vibrating electrode is formed at the end of the substrate. 5 is formed. Further, a ring-shaped protrusion 6 is provided around the vibrating electrode on the first main surface of the piezoelectric substrate 1.
is formed. Similarly, a ring-shaped protrusion (7) is also formed around the vibrating electrode on the second main surface of the piezoelectric substrate 1.

These vibrating electrodes and external connection electrodes can be formed by depositing silver electrodes on the entire surface of both surfaces of the piezoelectric substrate, patterning an etching resist, and etching.

Further, the annular protrusion shown in 6 and the like can be formed by printing solder resist ink around the vibrating electrode by squeegee printing, and then heating and drying.

FIGS. 1 and 3 show a state in which the piezoelectric element described above is temporarily fixed to the tips of the lead terminal and the auxiliary terminal. FIG. 1 is a perspective view, FIG. 3(A) is a front view, and FIG. 3(B) is a right side partial sectional view.

In FIG. 1, 21 is a part of the hoop material, and the strip part 1
Lead terminals io, it and auxiliary terminals 12 and 13 are integrally connected to the terminal 4. Piezoelectric elements 20 are temporarily fixed to the tips of these lead terminals and auxiliary terminals.

As shown in FIGS. 3(A) and 3(B), the piezoelectric element 20
The first main surface of the terminal contacts the lead terminal 10 and the auxiliary terminal 12, and the second main surface contacts the lead terminal 11 and the auxiliary terminal 13, and is temporarily fixed. At this time, lead terminals IO and 11 come into contact with external connection electrodes 4 and 5, respectively. Further, in this example, as shown in FIG. 3(B), the auxiliary terminals 12 and 13 abut the protrusions 6 and 7, respectively, and do not directly contact the vibrating electrodes 2 and 3. Note that the lead terminal 10 is omitted in FIG. 3(B).

The solder plating of the lead terminals 10, 11 and the auxiliary terminals 12, 13 is performed at once by soldering the entire terminals.

The soldering between the lead terminals 10 and 11 and the piezoelectric element 20 is as follows:
With the piezoelectric element temporarily fixed to the tip of each terminal, temperature-controlled hot air is jetted from a nozzle all around the piezoelectric element using a so-called hot air method to heat the tip of each terminal and the entire piezoelectric element. , solder the tip of the lead terminal to the external connection electrode.

Thereafter, a resin sheath is applied around the piezoelectric element if necessary, and at that time, wax for forming a cavity is dropped around the vibrating electrode. At this time, the protrusions 6 and 7 restrict the wax adhesion area, so as shown in FIG.
When the resin sheathing is applied using No. 5, cavities 8 and 9 having uniform cavity diameters are formed. Therefore, it is possible to easily obtain a piezoelectric component with uniform characteristics and excellent damping characteristics and spurious characteristics.

Note that since the auxiliary terminals 12 and 13 are not used as an electric circuit, they are removed by cutting and separating them before or after applying the resin sheath.

Although the example shows an example in which a ring-shaped protrusion is formed around the vibrating electrode, the shape of the protrusion is not limited to this, and any frame-shaped protrusion surrounding the vibrating electrode can be formed. You can get the same effect.

(Effects of the Invention As described above, according to this invention, when the piezoelectric element is temporarily fixed to the tip of the auxiliary terminal together with the lead terminal, even if the tip of the auxiliary terminal is close to the vibrating electrode, the tip of the auxiliary terminal Since the part does not come into direct contact with the vibrating electrode, it is possible to prevent silver leaching of the vibrating electrode during the subsequent soldering process.Additionally, cavity forming wax is dripped onto the vibrating electrode. When a resin exterior is applied, the frame-shaped protrusion restricts the wax adhesion area, so the cavity diameter becomes uniform and variations in characteristics can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a temporarily fixed state of a piezoelectric element in a method of manufacturing a piezoelectric component according to an embodiment of the present invention. Second
The figure is a front view showing the shape of the piezoelectric element. Figure 3 (
A) and (B) are a front view and a right side partial sectional view showing a temporarily fixed state of the piezoelectric element. FIG. 4 is a longitudinal sectional view showing the internal structure of the piezoelectric component after being covered with resin. FIG. 5 is a front view showing a state of a temporary fixing step of a piezoelectric element in a conventional piezoelectric component manufacturing method. 1-piezoelectric substrate, 2.3-vibration electrode, 4.5-external connection electrode, 6.7=protrusion, 10.11-lead terminal, 12.13-auxiliary terminal.

Claims (1)

[Claims] (1) Printing and forming a frame-shaped protrusion on the surface of the piezoelectric element and around the vibrating electrode, solder-plating at least the tips of the lead terminal and the auxiliary terminal, and placing the piezoelectric element between the tips of the lead terminal and the auxiliary terminal. A method of manufacturing a piezoelectric component, which comprises temporarily fixing the piezoelectric component to the piezoelectric component, and then soldering the tip of the lead terminal and the external connection electrode of the piezoelectric element by heating.