JPH05160660A - Production of piezoelectric parts - Google Patents

Abstract

PURPOSE:To provide excellent surface mountability and reliability and to inexpensively produce piezoelectric parts without damaging an armor resin layer by an easy method. CONSTITUTION:Terminals 6 and 7 preliminarily formed to a prescribed shape like L are attached to a piezoelectric element 1 and are coated with an armor resin 10a by dipping or the like. Thereafter, an armor resin layer 10b is formed by the facing molding where the armor resin 10a is molded with a pressure by a molding member having a flat face. Bottom faces of end parts of terminals 6, 7 and the bottom face of the armor resin layer 10b are placed on the same plane by this facing molding to secure the inline property.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a piezoelectric component, and more particularly to a method for manufacturing a piezoelectric component suitable for manufacturing a piezoelectric component such as a piezoelectric filter using an energy trap type piezoelectric resonator. It is a thing.

[0002]

2. Description of the Related Art Conventionally, piezoelectric components having various package shapes, for example, piezoelectric components having a flat pack type package shape have been widely used. A piezoelectric component having the above package shape is usually composed of a piezoelectric element and a terminal, and the piezoelectric element has a piezoelectric substrate, a resonator electrode portion, and an external connection electrode extending from the electrode portion. A terminal is connected to the external connection electrode.

A piezoelectric component is manufactured by coating the piezoelectric element with an exterior resin and subjecting it to surface molding. More specifically, as shown in FIG. 2 (A), flat plate terminals 24 and 26 are used in order to improve workability in manufacturing the piezoelectric component. The terminals 24 and 26 are external connection electrodes 23 extending from the resonator electrode portion 22 formed on one surface of the piezoelectric substrate 21 by solder 27, and an earth electrode portion formed on the other surface of the piezoelectric substrate 21. 25 and 25, respectively.

Wax 29 is applied to the resonator electrode portion 22 and its peripheral portion of the piezoelectric element 28 having the above-mentioned structure to form the terminal 2
Dip in the resin solution except for parts 4 and 26, and
As shown in (B), it is covered with an exterior resin 30a that can be softened in a semi-cured state.

Next, as shown in FIG. 2 (C), the facing surface of the exterior resin 30a is subjected to parallel surface molding,
The exterior resin 30a is heated and cured to form the exterior resin layer 30b molded into a predetermined shape. At this time, the wax 29 is cured by heating and absorbed by the exterior resin 30a to form the vibration space 31. Then, the end portions of the terminals 24 and 26 are formed into a predetermined bent shape in order to form a surface mountable piezoelectric component.

To mount the piezoelectric component manufactured as described above, generally, as shown in FIG. 3, the conductor pattern 33 of the circuit board 32 and the ends of the terminals 24 and 26 are connected by solder 34 or the like. Performed by. Therefore, when molding the terminals 24 and 26,
It is necessary to position the bottom surface of the end portion of No. 6 on the substantially same plane as the bottom surface of the exterior resin layer 30b, and perform molding so as to ensure in-line property.

[0007]

However, according to the above-mentioned manufacturing method, the exterior resin layer 30 is cured by heating.
After forming b, in order to form the flat terminals 24 and 26 into a predetermined shape, for example, the bottom surface of the exterior resin layer 30b,
The end bottom surfaces of the terminals 24 and 26, which are planarized on the conductor pattern 33 on the circuit board 32, are not necessarily located on substantially the same plane, and the bending positions of the end bottom surfaces of the terminals 24 and 26 are not uniform and are inline. It is difficult to secure sex. Therefore, the terminal 2 is formed on the conductor pattern 33 of the circuit board 32.
Even when the bottom surfaces of the end portions of the terminals 4 and 26 are placed, a gap portion is formed between the conductor pattern 33 and the bottom surfaces of the end portions of the terminals 24 and 26, or between the circuit board 32 and the exterior resin layer 30b. Three
2 has a problem that surface mountability and reliability are degraded.

Further, since the resin surface forming step and the terminal forming step are required, the number of steps is not large and it is not economical, and after forming the exterior resin layer 30b, the flat terminals 24 and 26 are formed. Since the molding process is performed in a bent shape, the exterior resin layer 30b may be damaged by the subsequent molding process of the terminals 24 and 26.

The present invention has been made in view of the above points, and provides a piezoelectric component that simplifies the processing method, has excellent surface mountability and reliability, and is inexpensive and can prevent damage to the exterior resin layer. It is intended to provide a manufacturing method.

[0010]

SUMMARY OF THE INVENTION According to the present invention, a piezoelectric component is characterized in that a terminal formed in a predetermined shape in advance is attached to a piezoelectric element, covered with an exterior resin, and then the exterior resin is subjected to chamfering molding. The above-mentioned problems are solved by the manufacturing method of.

[0011]

According to the present invention having the above-mentioned structure, since the terminals formed in a predetermined shape in advance are attached to the piezoelectric element and covered with the exterior resin, the exterior resin is subjected to chamfering molding. At the time of processing, the bottom surface of the end portion of the terminal can be positioned substantially on the same plane as the bottom surface of the molded exterior resin layer. Therefore, it is possible to ensure the in-line property between the bottom surface of the terminal end and the bottom surface of the exterior resin layer. In addition, after the outer resin layer is formed, the terminal is preliminarily molded into a predetermined shape without molding the terminal. Therefore, not only the molding of the terminal is unnecessary, but also the outer resin layer may be damaged. Absent.

[0012]

An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a process chart showing a method of manufacturing a piezoelectric component of the present invention. The present invention relates to a terminal mounting step (A) for mounting a terminal, which is preformed into a predetermined shape, on a piezoelectric element
And a coating step (B) of coating with the exterior resin, and a resin molding step (C) of surfacing and molding the resin.
In this example, a piezoelectric filter is used as the piezoelectric component.

The piezoelectric element 1 used in the terminal mounting step (A) has a resonator electrode portion 3 formed on one surface of a piezoelectric substrate 2 and an external connection extending from the resonator electrode portion 3. It has an electrode 4 and a ground electrode portion 5 formed on the other surface of the piezoelectric substrate 2.

The external connection electrode 4 and the ground electrode portion 5 are respectively formed with terminals 6, which are preliminarily formed into a predetermined shape.
7 are connected by a conductive paste or solder 8. In this example, the ends of the terminals 6 and 7 are formed into an L shape.

In the coating step (B), in order to secure the vibration space, the resonator electrode portion 3 and its peripheral portion are coated with the vibration space forming material 9, and then the terminals 6, 7 of the piezoelectric element 1 are covered. It is covered with the exterior resin 10a except for the portion.

The types and amounts of the vibration space forming material 9 and the exterior resin 10a are appropriately selected according to their characteristics, and the resonator electrode portion 3 and the exterior resin layer 10b formed in the resin molding step (C). Any material can be used as long as it can form the vibration space 11 between them. Examples of the vibration space forming material 9 include synthetic or natural waxes such as polyethylene, polypropylene, paraffin wax, carnauba wax, and microcrystalline wax. The vibrating space forming material 9 is solid or semi-solid at room temperature, easily softened by heating, and melts at a relatively low temperature.

As the exterior resin 10a, polyethylene, polypropylene, polyester, acrylic resin,
Styrenic resin, thermoplastic resin such as polycarbonate, phenol resin, epoxy resin, unsaturated polyester, thermosetting resin such as diallyl phthalate resin,
Various resins can be used.

The vibrating space forming material 9 is absorbed by the exterior resin 10a as a result of the resin molding step (C) or subsequent heating, and the resonator electrode portion 3 and the exterior resin layer 10b.
A vibrating space 11 is formed between and. This vibration space 11
The layer (1) can be formed in an appropriate size, but a few microns is usually sufficient.

The coating with the vibrating space forming material 9 can be performed by various means such as dropping, printing and coating of the vibrating space forming material 9. The coating with the exterior resin 10a may be performed by a coating means such as dipping or coating on the resin solution, or a molding means such as molding.

When a thermoplastic resin is used as the exterior resin 10a and the piezoelectric element 1 is coated with the exterior resin 10a by molding, the resin molding step (C) is not always necessary, and the coating step with the exterior resin 10a is not necessary. You may perform (B) and resin molding process (C) simultaneously.

Exterior resin 10 covering the piezoelectric element 1
Since a is molded into a predetermined shape in the resin molding step (C), it may be at least in a softenable state, and a thermosetting resin may be in a moldable semi-cured state.

Further, the coating amount of the exterior resin 10a is set so that the bottom surfaces of the end portions of the terminals 6 and 7 and the bottom surface of the exterior resin layer 10b are located on the same plane in the resin molding step (C) to ensure in-line property. It is sufficient that the amount is sufficient, and normally, the covering resin 10a is coated so that the thickness thereof is larger than the bottom surfaces of the ends of the terminals 6 and 7 in the thickness direction.

In the resin molding step (C), the exterior resin 10a is subjected to surfacing molding into a predetermined shape. In this example, the upper and lower surfaces of the exterior resin 10a are pressed with a pair of molding dies 12a and 12b having flat surfaces to form the exterior resin layer 10b having a predetermined shape.

When resin molding is performed as described above, the bottom surfaces of the ends of the terminals 6 and 7 can be pressed against the molding die 12b, and
By the surfacing molding of the pair of molding dies 12a and 12b,
The bottom surface of the exterior resin layer 10b can be located on the same plane as the bottom surfaces of the end portions of the terminals 6 and 7, and there is no variation, and a piezoelectric component having excellent in-line property and surface mountability can be obtained.

Further, by heating after the resin molding step (C) or after passing through the step, as described above, the vibration space 1 is provided between the resonator electrode portion 3 and the exterior resin layer 10b.
1 is formed.

The surfacing molding is not limited to the molding die, but can be carried out by various methods of pressure-molding the exterior resin to form the exterior resin layer. For example, a molding die in which a convex portion is formed on one of the pair of molding dies 12a and 12b is used, and the bottom surface of the end portion of the terminals 6 and 7 is formed on either one of the molding dies 12a and 12b by the convex portion. You may shape | mold by pressing to. Further, the convex portion may be formed of an elastic member or a biasing member that elastically presses or biases.

The resin molding step can be carried out at an appropriate pressure and temperature depending on the type of the exterior resin 10a used. At that time, when a thermosetting resin is used as the exterior resin 10a, it is necessary to cure the resin.

Further, in this example, after the resin molding step (C), the end portions of the terminals 6 and 7 are cut to a predetermined length in the terminal cutting step (D). By doing so, even with an extremely small piezoelectric component, the ends of the terminals 6, 7 can be reliably pressed by the molding dies 12a, 12b, so that there is no variation and a piezoelectric component excellent in inline property is manufactured with good productivity. be able to.

The terminal cutting step (D) is not always necessary, and a terminal that has been previously formed into a predetermined shape and a predetermined length may be used.

The piezoelectric component manufactured as described above is
For example, even if the end portions of the terminals 6 and 7 are placed on the conductor pattern of the circuit board, there is a gap between the conductor pattern and the bottom surface of the end portions of the terminals 6 and 7 or between the circuit board and the exterior resin layer 10b. Since there is no part, it can be mounted in a stable state, and the conductor pattern and the ends of the terminals 6 and 7 can be directly connected by planarization with a conductive bonding agent such as conductive paste or solder, and surface mounting. It has excellent properties.

The present invention can be applied not only to the case where the terminals are planarized on the conductor pattern of the circuit board, but also to the piezoelectric components having various package shapes. It may be preliminarily formed into an appropriate shape, such as an L-shape, within a range that does not impair

Further, the present invention can be applied not only to the two-terminal type piezoelectric component but also to the three-terminal type piezoelectric component, and the terminals are formed at appropriate places such as one side or both sides of the piezoelectric component according to the application of the piezoelectric component. May be.

The vibrating space is not always necessary, and the piezoelectric element may be sequentially covered and covered with an elastic silicone resin or the like and an exterior resin depending on the structure of the piezoelectric element.

Further, the piezoelectric element is not limited to the thickness-shear vibration mode, but various energy trapping modes such as a thickness longitudinal vibration mode, a width vibration mode and a thickness torsion vibration mode can be used. The present invention can be applied to piezoelectric components such as a two-stage bandpass filter, an intermediate frequency resonator, a trap, an oscillator and a strain sensor.

As the piezoelectric substrate, various materials such as single crystal, polycrystal and ceramics exhibiting piezoelectricity can be used.

[0037]

As described above, according to the present invention, the terminals which are formed in a predetermined shape in advance are attached to the piezoelectric element, coated with the exterior resin, and then the exterior resin is chamfered and formed.
The processing method can be simplified, the cost is low, the surface mountability and the reliability are excellent, and damage to the exterior resin layer can be prevented.

[Brief description of drawings]

FIG. 1 is a process chart showing a method for manufacturing a piezoelectric component of the present invention.

FIG. 2 is a process drawing showing an outline of a conventional method for manufacturing a piezoelectric component.

FIG. 3 is a schematic view showing a surface mounting state of a piezoelectric component obtained by a conventional method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Piezoelectric element 6, 7 ... Terminal 10a ... Exterior resin 10b ... Exterior resin layer 12a, 12b ... Mold

Claims (1)

[Claims] 1. A method of manufacturing a piezoelectric component, wherein a terminal, which is molded in a predetermined shape in advance, is attached to a piezoelectric element, is covered with an exterior resin, and then the exterior resin is subjected to chamfering molding.