JPH034131B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a method of manufacturing a piezoelectric resonator device.
In particular, the present invention relates to a method of manufacturing a piezoelectric resonator device that integrates, for example, an energy-trapping thickness-shear vibration resonator with another circuit element such as a load capacitor.

(Description of Prior Art) A piezoelectric oscillator has been proposed in which, for example, an energy confinement type thickness-shear vibration resonator and two load capacitors are integrated and the integrated unit is housed in a molded resin case. ing. Although this piezoelectric oscillator has many advantages, it also has the following drawbacks. In other words, the conventional piezoelectric oscillator is
Since an insert-molded resin case is used, the cost of the case and its materials is high. Also, since the inner case is used to form a gap in the vibration area,
It becomes a double case along with the outer case,
This not only led to increased costs, but also made the structure complex, making parts and process management complicated.

(Objective of the Invention) Therefore, an object of the present invention is to provide a method for easily and inexpensively manufacturing a piezoelectric resonator device that integrates an energy trapping type piezoelectric resonator and other circuit elements. That's true.

(Summary of the Invention) Briefly, the present invention comprises filling a space between a vibrating surface of an integrated energy-trapping piezoelectric resonator and another circuit element with a sublimation agent or a material that is easily vaporized; At least the vibration region of the energy-trapping piezoelectric resonator is covered with a material that is solid or semi-solid at room temperature and easily melts when heated, and in that state, the entire body is covered with a thermosetting resin, and when this resin is heated and cured, A method for manufacturing a piezoelectric resonator device, in which a sublimating agent or a material that is easily vaporized and a material that is solid or semi-solid at room temperature and easily melted by heating are removed to form voids therein. .

The above objects and other objects and features of the invention will become more apparent from the following detailed description with reference to the drawings.

(Description of Embodiments) FIG. 1 is a perspective view showing an example of a piezoelectric resonator device that forms the background of the present invention and to which the present invention is applied. This piezoelectric resonator device 10 includes a resonator substrate 12 for a piezoelectric resonator, and this resonator substrate 1
2 is made of, for example, lead zirconate titanate ceramic which has been polarized. Excitation electrodes 14 and 16 made of metal such as silver are provided on both main surfaces of the resonator substrate 12, respectively.
is formed. These excitation electrodes 14 and 16
are opposed to each other with the resonator substrate 12 in between. This substrate 12 and electrode 1
In this example, 4 and 16 constitute a resonator that utilizes energy-trapped thickness-shear vibration. However, the vibration mode of this resonator is not limited to such thickness shear vibration, and may be any mode as long as it is an energy trap type resonator. Excitation electrode 1 of resonator substrate 12
An input electrode 18 is formed on the main surface where 4 is formed, at an end opposite to the side where this excitation electrode 14 is formed.

A capacitor substrate 22 is integrally attached above the resonator substrate 12 via a spacer 20 made of, for example, rubber or adhesive. This capacitor substrate 22 is made of, for example, lead zirconate titanate ceramic that is not subjected to polarization treatment, and has a first capacitor electrode 24 and a second capacitor electrode 26 formed at both ends of the main surface. Ru. A ground electrode 28 is formed approximately at the center of the other main surface of the capacitor substrate 22 . The first capacitor electrode 24 and the vibrating electrode 16, that is, the input electrode 18, are electrically connected by an end electrode 30, and the second capacitor electrode 26 is electrically connected to the vibrating electrode 14 by an end electrode 32. There is. Therefore, the piezoelectric resonator device shown in FIG. 1 has the circuit configuration of the device 10 surrounded by the two-dot chain line in FIG. Note that it is preferable to integrally form the spacer 20 and the end electrodes 30 and 32 with a conductive adhesive in terms of connection reliability.

Input electrode 18, ground electrode 28 and vibration electrode 1
4 have an input terminal 36 and a ground terminal 34, respectively.
and an output terminal 38 are electrically connected and mechanically fixed, for example, by soldering or the like. The resonator substrate 12 and capacitor substrate 22 are integrally covered with a resin sheath 40 so that the tips of these terminals 36, 34, and 38 are exposed.

In the example shown in FIG. 1, a piezoelectric resonator device having an equivalent circuit shown in FIG. 2 has been described. However, other circuit elements integrated with the resonator substrate 12 are not limited to capacitors, but may be other passive components or active components.

3 to 5 are diagrams explaining the manufacturing method of the piezoelectric resonator device shown in FIG. 1 step by step, and FIG. 4 and FIG. show.

As shown in FIG. 3, first, the resonator substrate 12 and the capacitor substrate 22 are connected using the spacer 20 (FIG. 1).
Unify through. And each terminal 36, 34
and 38 are electrically connected and mechanically fixed to predetermined electrodes, for example, by soldering or the like.

Next, as shown in FIG. 4, the gap between the integrated resonator substrate 12 and capacitor substrate 22 is filled with naphthalene 42. This is accomplished by immersing the monolith shown in FIG. 3 in a solution of naphthalene. In addition, naphthalene 42
Alternatively, other subliming agents may be used, such as phthalic anhydride, benzoic acid, etc., or other easily vaporized materials may be filled. next,
The one piece is immersed in the melted wax, and wax 44 is deposited thereon as shown in FIG. At this time, there is a naphthalene 42 between the substrates 12 and 22.
is filled, so wax will not seep into the gap. Also, the wax 44 must be applied at least to the vibrating region of the piezoelectric resonator. Note that in place of the wax 44, other materials that are solid or semi-solid at room temperature and easily melt by heating may be used.

Next, in the state shown in FIG.
A resin sheath 40 as shown in the figure is formed. As the material used for this resin sheath 40, porous resin is preferably used. Since it is a thermosetting resin, the naphthalene 42 is vaporized by heating when forming the resin sheath 40, and the wax 44 is absorbed by the resin sheath 40 or scattered to the outside through the resin sheath 40. Therefore, the portion where naphthalene 42 and wax 44 were present in FIG. 4 is formed as a void as shown in FIG. 5. Note that the resin exterior 40 may be further covered with a resin coating 46 having better heat resistance and moisture resistance.

(Effects of the Invention) As described above, according to the present invention, the space between the vibrating surface of an energy-trapping piezoelectric resonator and another circuit element is filled with, for example, a sublimation agent, and then the vibrating region is covered with, for example, wax. Since a resin exterior is then formed, for example, wax will not get in between the vibrator and another circuit element, and
Therefore, the vibration of the vibrator is not hindered. Furthermore, since it does not use an insert-molded resin case or a double case like conventional ones, the structure is simple and the number of parts is small. This also makes process control easier, which ultimately results in a piezoelectric resonator device with better performance. Obtained cheaply.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an example of a piezoelectric resonator device that forms the background of the present invention and in which the present invention is utilized. FIG. 2 is an equivalent circuit of the device shown in FIG. 3 to 5 are diagrams for explaining one embodiment of the present invention in the order of steps, and FIGS. 4 and 5 show a cross section taken along line A--A in FIG. 3. In the figure, 10 is a piezoelectric resonator device, 12 is a resonator substrate, 14 is a capacitor substrate, 20 is a spacer, 40 is a resin exterior, 42 is naphthalene, and 44 is wax.

Claims (1)

[Claims] 1. A step of integrating an energy confinement type piezoelectric resonator and another circuit element spaced above the vibration plane of the piezoelectric resonator, said integrated energy confinement type piezoelectric resonator. filling a space between the element and the circuit element with a sublimating agent or a material that is easily vaporized; and a step of covering the whole in the covered state with a thermosetting resin, and when curing the thermosetting resin, the sublimating agent or a material that easily vaporizes and the room temperature A method for manufacturing a piezoelectric resonator device, in which solid or semi-solid materials that are easily melted by heating are removed, and voids are formed in the areas where they were present.