JPH0738365A - Energy confinement type resonator and its manufacture - Google Patents

Abstract

PURPOSE:To prevent a fact that residual wax is remelted by reheating and suppresses vibration of a vibration electrode by forming a void in the vibration electrode part by a sheathing resin containing silicone, and covering a piezoelectric substrate. CONSTITUTION:On a piezoelectric substrate 1, a vibration electrode 2a, and a drawer electrode 2b led out in the opposite directions, respectively from the vibration electrode 2a are formed, and an external terminal 3 is soldered to the drawer electrode 2b. Subsequently, to the vibration electrode 2a on both faces and an area being wider than this electrode, one component type thermosetting silicone whose surface tension is small and whose permeability is strong is applied. Next, to the piezoelectric substrate 1, the thermosetting silicone and a connected part of the external terminal 3, a sheathing resin 5 consisting of a porous thermosetting resin is applied by an immersion method. Thereafter, that which is applied by the sheathing resin 5 is put into an oven, heated and the sheathing resin 5 is hardened porously, and simultaneously, silicone is infilterated into a calcined pore of the sheathing resin 5, and also, hardened, and a void 6 is formed in the part on which silicone is applied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an energy trap type resonator and a method for manufacturing the resonator.

[0002]

2. Description of the Related Art Conventionally, a method for manufacturing this type of energy trap type resonator is described in Japanese Patent Publication No. 45-22384. In the manufacturing method in this conventional example, as the void-forming agent, a substance that causes melting and evaporation by heating or a substance that vaporizes, such as paraffin and wax, is disclosed. Then, with this conventional technique, a huge number of filters such as a filter using an energy trap type resonator, for example, a 10.7 MHz filter for FM radio, a 4.5 MHz filter for TV, etc. are produced and used in AV products around the world. Has been done.

[0003]

However, when this conventional manufacturing method is carried out in steps, the following problems sometimes occur due to process control errors. That is, the wax is completely melted by heating and is not absorbed by the exterior resin, or is not evaporated outside the exterior resin and remains on the electrode, and the load of the residual wax deteriorates the electrical characteristics. Even if the initial characteristics satisfy the specifications and are shipped from the factory, they are incorporated into the set and the set is operated, and the set heats up due to the operating heat of the circuit, and the temperature rises to 50 ° C.
When the temperature reaches -60 ° C, this temperature is just the melting temperature of the wax, so the residual wax remelts and becomes viscous, suppressing the electrode vibration, and the characteristics fluctuate and deteriorate.
If this is a ceramic oscillator, it will oscillate with normal amplitude when the residual wax is solidified,
As described above, when the temperature reaches 50 ° C. to 60 ° C., the residual wax is re-melted and becomes viscous to suppress the electrode vibration, so that the oscillation amplitude becomes small and the oscillation stops. But,
When the set is turned off and turned on after a while, the ceramic filter with deteriorated characteristics or the ceramic oscillator whose oscillation is stopped always operates because the wax is cooled and solidified. And the set gets hot and 50
When the temperature reaches 60 ° C to 60 ° C, the defective mode as described above is repeated again. However, after repeating this cycle many times, this failure mode does not occur. This is because the wax is melted by heat and absorbed by the exterior resin or evaporated during this cycle.

Accordingly, the present invention uses a thermosetting silicone having a low surface tension and a high permeability as a void-forming agent to remove any residual silicone on the vibrating electrode after heat treatment. It is an object of the present invention to provide a energy confinement type resonator and a method for manufacturing the same, which does not suppress the vibration of the vibrating electrode by being re-melted by reheating because it is thermally cured.

[0005]

According to one aspect of the present invention, energy confinement type vibrating electrodes are provided on both surfaces of a piezoelectric substrate, an extraction electrode is led out from the vibrating electrode, and an external terminal is connected to the extraction electrode. Energy confinement type in which the piezoelectric substrate and the external terminal are connected to each other, and a void is formed in the upper part of the vibrating electrode and an area slightly larger than the vibrating electrode, and the piezoelectric substrate and the external terminal are covered with an exterior resin containing silicone. As the resonator, two are provided with an energy trapping vibrating electrode on both sides of the piezoelectric substrate and an extraction electrode from this vibrating electrode, an external terminal is connected to the extraction electrode, and the vibrating electrode and this vibrating electrode are slightly A large area is coated with thermosetting silicone, the external terminals are connected, and the piezoelectric substrate coated with thermosetting silicone is porous. Coating with a curable resin, heat-curing the porous thermosetting resin to form pores, and allowing the silicone to penetrate and cure into the pores to form voids in the portion where the silicone was applied. The present invention is a method for manufacturing an energy trap type resonator having the following structure.

[0006]

The energy trap type resonator according to the present invention is
With the exterior resin containing silicone, the piezoelectric substrate is covered with voids formed in the vibrating electrode part, and even if there is residual silicone on the vibrating electrode, the residual silicone is cured by heating. So remelt it,
The vibration of the vibrating electrode is not suppressed. Further, in the method of manufacturing the energy trap type resonator, since the thermosetting silicone having a small surface tension and a high permeability is used as the void forming agent, the porous thermosetting resin is cured by heating. A pore will be formed into which the silicone will penetrate and cure.

[0007]

Embodiments of the present invention will now be described with reference to the drawings. In the process shown in FIG. 1, the vibrating electrode 2a of the energy trap type resonator is provided at the center of both surfaces of the piezoelectric substrate 1, and the extraction electrodes 2 are respectively led out in opposite directions from the vibrating electrode 2a.
b is formed by vapor deposition or sputtering, and the external terminal 3 is soldered to the extraction electrode 2b.

In the process shown in FIG. 2, the one-component thermosetting silicone 4 having a small surface tension, a high penetrability and a viscosity of 35 p (at 25 ° C.) is applied to the vibrating electrodes 2a on both sides and an area slightly wider than the vibrating electrodes 2a. It is applied with a dispenser.

In the step shown in FIG. 3, the exterior resin 5 made of a porous thermosetting resin such as an epoxy resin is applied to the connection portion of the piezoelectric substrate 1, the thermosetting silicone 4 and the external terminal 3 by a dipping method. Is.

In the process of FIG. 4, the product coated with the exterior resin 5 shown in FIG. 3 is placed in an oven at 150 ° C. for 120
By heating for 5 minutes to cure the exterior resin 5 into a porous state, at the same time, the silicone 4 is allowed to penetrate into the firing pores of the exterior resin 5 and cured to form a void 6 in the portion where the silicone was applied. It is a thing.

The method of manufacturing the energy trapping resonator according to the present invention comprises the steps as described above, and the energy trapping resonator manufactured by this manufacturing method has the following structure. That is, energy confinement type vibrating electrodes are provided on both surfaces of a piezoelectric substrate, lead electrodes are led out in opposite directions from the vibrating electrodes, and external terminals are respectively solder-connected to the lead electrodes. The energy confinement type resonator in which a connecting portion of the above is formed with a void above the vibrating electrode and an area slightly wider than the vibrating electrode and is covered with an exterior resin containing silicone.

[0012]

The energy trap type resonator according to the present invention is an exterior resin containing silicone, in which a gap is formed in the vibrating electrode portion and the piezoelectric substrate is covered.
Even if there is residual silicone on the vibrating electrode,
Since the residual silicone is hardened by heating, it does not re-melt and suppress the vibration of the vibrating electrode unlike the wax used in the conventional example. Further, since the silicone penetrates into the pores of the exterior resin and is cured, it has excellent moisture resistance. Further, in the method of manufacturing the energy trap type resonator, since the thermosetting silicone having a low surface tension and a high permeability is used as the void forming agent, the wax remaining in the voids is larger than the wax used in the conventional example. Is less.

[Brief description of drawings]

FIG. 1 is a process diagram of providing a vibrating electrode, a lead electrode, and an external terminal on a piezoelectric substrate in a manufacturing method of the present invention.

FIG. 2 is a process diagram of applying thermosetting silicone to the vibrating electrode shown in FIG. 1 and an area slightly wider than it.

3 is a process diagram in which the piezoelectric substrate, the thermosetting silicone, and the external terminal connecting portion shown in FIG. 2 are immersed in a porous thermosetting resin to provide an exterior resin.

FIG. 4 is a diagram showing a case in which the coating of the exterior resin shown in FIG. 3 is heated to cure the exterior resin into a porous structure, and at the same time, silicone is allowed to penetrate into the firing pores of the exterior resin and to be cured to apply the silicone. Process drawing to form a void in the part that had been

[Explanation of symbols]

 1 Piezoelectric Substrate 2a Vibration Electrode 2b Lead-out Electrode 3 External Terminal 4 Thermosetting Silicone 5 Exterior Resin 6 Void

Claims (2)

[Claims] 1. An energy trapping type vibrating electrode is provided on both surfaces of a piezoelectric substrate, a lead electrode is led out from the vibrating electrode, and external terminals are respectively connected to the lead electrode, and the piezoelectric substrate and the external terminal are connected. An energy trapping resonator in which a portion is covered with an exterior resin containing silicone in which a void is formed above the vibrating electrode and an area slightly wider than the vibrating electrode. 2. An energy trapping type vibrating electrode and a lead electrode from the vibrating electrode are formed on both surfaces of a piezoelectric substrate, an external terminal is connected to the lead electrode, and the vibrating electrode and an area slightly wider than the vibrating electrode are provided. A thermosetting silicone is applied, the piezoelectric substrate to which the external terminals are connected and thermosetting silicone is applied is covered with a porous thermosetting resin, and the porous thermosetting resin is heat-cured to form a pore. And a method of forming an air gap in the portion where the silicone has been applied by infiltrating the silicone into the pores and curing the silicone.