JPH01125011A - Coating method for cavity forming material of resin sealing type resonator - Google Patents

Abstract

PURPOSE:To simultaneously form a film of a cavity forming material on a vibrating electrode of the surface and the reverse side of a piezoelectric substrate by supplying a droplet of the cavity forming material of a prescribed quantity to the upper end part, in a state that the piezoelectric substrate is erected in the vertical direction. CONSTITUTION:A resonator 1 to which terminals 10, 20 are connected is erected in the vertical direction, and from its upper part, a trowel 40 of an applying device is brought close. To the tip part of the trowel 40, a cavity forming material 50 being in a molten state is allowed to adhere. The tip of the trowel 40 is brought into contact with or brought close to the upper end of the resonator 1, and a droplet of the cavity forming material 50 is shifted onto the resonator 1. Thereafter, the resonator 1 is sealed with an insulating resin 30 by a technique of an immersion method, a mold method, etc., and the cavity forming material 50 is absorbed by the insulating resin 30, by which a cavity 31 is formed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method of applying a cavity forming material to form a cavity around a vibrating electrode when sealing a piezoelectric common grip with a resin. It is.

(Prior art and its problems) Conventionally, in this type of resin-sealed resonator, vibration was used as a method of forming a cavity around the vibrating electrode when the piezoelectric substrate on which the vibrating electrode was formed was sealed with resin. A cavity-forming material such as wax or paraffin that is solid or semi-solid at room temperature, easily softens when heated, and melts at a relatively low temperature is applied around the electrode in advance, and then heated during or after sealing with the insulating resin. However, a method is known in which the cavity-forming material is melted and absorbed into an insulating resin (Japanese Patent Publication No. 45-22
Publication No. 384).

When applying a cavity forming material as described above to a piezoelectric substrate, first turn the piezoelectric substrate face up and apply the cavity forming material onto the vibrating electrode on the front side, then turn the piezoelectric substrate over and apply the cavity forming material onto the vibrating electrode on the back side. It is necessary to perform two application operations to apply the cavity forming material.

Therefore, there are problems in that workability is poor, the coating process takes time, and if the coating process is attempted to be automated, the size of the apparatus increases.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to form a film of a cavity forming material on the vibrating electrodes on the front and back surfaces in a single coating operation without turning the piezoelectric substrate upside down. An object of the present invention is to provide a method for applying a cavity forming material for a resin-sealed resonator with excellent properties.

[Structure of the invention]

In order to achieve the above object, the method for applying a cavity forming material of the present invention includes the step of vertically standing up a piezoelectric substrate, bringing a cavity forming material application device close to the upper end of the upright piezoelectric substrate, and applying a cavity forming material from the application device to the piezoelectric substrate. A step of supplying a drip of molten cavity forming material to the upper end of the substrate, and a step of solidifying or half-forming the drip in a state where the drip flows to a position covering at least the vibrating electrode on the front and back surfaces of the piezoelectric substrate. It includes.

[Effect]

When a certain amount of droplets of cavity-forming material are supplied to the top end of the piezoelectric substrate in a vertically erected state, the droplets flow along both sides of the piezoelectric substrate due to gravity and cover the vibrating electrodes. That is, the cavity forming material can be applied onto the vibrating electrodes on the front and back surfaces in one dripping operation without inverting the piezoelectric substrate. If the cavity-forming material is solidified or halved while covering the vibrating electrode, the cavity-forming material will not flow to other parts during transfer to the next resin sealing step.

(Example) FIGS. 1 and 2 show a resin-sealed resonator manufactured by the method of the present invention.

In the drawing, the resonator I has an energy-trapped thickness longitudinal vibration mode structure, and its outer periphery is sealed with an insulating resin 30 with terminals 10 and 20 connected.

The resonator 1 includes a piezoelectric substrate 2 made of a square thin ceramic plate, an electrode 3 provided on the surface thereof, and an electrode 4 of the same shape provided on the surface at a position 180 degrees symmetrical with the electrode 3. The provided electrode 3 on the front surface connects a circular vibrating part (vibrating electrode) 3a located at the center of the board, a terminal part 3b formed on one side edge of the board, and both parts 3a and 3b. The electrode 4 on the back side
Similarly, it is composed of a vibrating part (vibrating electrode) 4a, a terminal part 4b, and a drawer part 4c. In addition, the vibrating parts 3a, 4a
By providing two each of the lead-out parts 3c and 4c that connect the terminal parts 3b and 4b, it is possible to prevent the lead-out parts 3c and 4c from being disconnected due to the solder eating phenomenon. Further, the electrodes 3.4 have the same shape and 180@ on the front and back surfaces of the substrate 2.
Since they are formed in symmetrical positions, there is no directionality, and assembly using an automatic machine is easy.

The two terminals 10.20 are punched out from a hoop material (not shown) using a press, and the upper ends of the terminals 10.20 are connected to the terminal portions 3b and 4b of the electrodes 3 and 4 by means of a cow type or the like. ing. The lower half of the terminal 10.20 is exposed from the insulating resin 30.

The insulating resin 30 seals the entire circumference of the resonator 1 using a dipping method or a molding method, and in particular, the electrodes 3.
Since the cavity 31 is formed around the vibrating parts 3a and 4a of No. 4, the thickness longitudinal vibration of the vibrating parts 3a and 4a occurs.

is not inhibited.

In the resin-sealed resonator having the above structure, the method for forming the cavity 31 is as described in the above-mentioned Japanese Patent Publication No. 1973-11. This method is similar to the method described in Japanese Patent No. 2384. That is, terminal 10. is connected to resonator l.
20 is connected, vibrating parts 3a and 4g on the front and back sides of the
A cavity forming material such as wax, tux or paraffin which is solid or semi-solid at room temperature, easily softens when heated, and melts at a relatively low temperature is applied on top, and when or after sealing is applied with an insulating resin 30. The cavity 31 is formed by heating and absorbing the cavity forming material into the porous insulating resin 30 .

Here, a method of applying a cavity forming material to the front and back vibrating parts 3a and 4a of the resonator l, which is the main part of the present invention, will be explained in Figs.
This will be explained next with reference to FIG.

First, as shown in FIGS. 3 and 4, the resonator 1 to which the terminals IQ and 20 are connected is vertically erected, and the iron 40 of the coating device is approached from above. A predetermined amount of cavity-forming material 50 is attached to the tip of the trowel 40 by dipping the tip into an oak containing molten cavity-forming material 50 and then pulling it up Lf. Since the iron 740 is constantly heated, the cavity forming material 50 is maintained in a molten state.

Next, as shown in FIGS. 5 and 6, the tip of the iron 40 is brought into contact with or close to the upper end of the resonator 1, and the droplet of the cavity forming material 50 is transferred onto the resonator 1. At this time, the cavity forming material 5
so that 0 is almost evenly supplied to the front and back surfaces of the resonator 1.
It is necessary to position the iron 40 at the center of the upper end of the resonator 1.

Next, as shown in FIGS. 7 and 8, when the iron 40 is removed from the upper end of the resonator 1, the cavity forming material 50 flows downward due to gravity and covers the vibrating parts 3a and 4a of the electrodes 3 and 4. reach the position.

The cavity forming material 50 that has left the iron 40 begins to solidify or become half-sided due to the outside temperature, and the vibrating portion 3a.

When the flow reaches 4a, solidification or half-layering is almost completed. Therefore, even if some time passes or vibration is applied during the transfer from the coating process of the cavity forming material 50 to the resin sealing process, there is no risk that the cavity forming material 50 will fall off the resonator 1.

Note that in the above method, the cavity forming material 5 supplied to the resonator 1
Although the case where the drip of 0 solidifies or becomes half-sided due to natural cooling is shown, solidification or half-sidedness may be promoted by blowing cold air.

After applying the cavity forming material 50 on both the front and back surfaces as described above,
A cavity 31 is formed by sealing the resonator 1 with an insulating resin 30 by a method such as a dipping method or a molding method, and absorbing the cavity forming material 5o into the insulating resin 30.

It should be noted that if the cavity 31 is formed only in the vibrating parts 3a, 4a of the electrodes 3, 4 and the vicinity thereof, unnecessary vibrations (spurious) can be effectively removed by the damping function of the insulating resin 30. A resonator is obtained. Therefore, the dripping amount of the cavity forming material 50 is adjusted so that the cavity forming material 50 is solidified or half-sided just on the vibrating parts 3a, 4a.
It is desirable to select the viscosity, temperature, etc.

Further, in the above embodiment, the application device is an example of the iron 40, but the present invention is not limited to this, and for example, a droplet of the cavity forming material may be supplied from a nozzle to the upper end of the resonator.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, vibrations of the front and back surfaces of the piezoelectric substrate are generated by supplying a certain amount of a cavity forming material droplet to the upper end of the piezoelectric substrate while the piezoelectric substrate is vertically erected. Since the film of the cavity forming material can be simultaneously formed on the electrode, the application work can be completed in one drip operation without reversing the piezoelectric substrate. Therefore, workability is extremely good and coating processing time can be significantly shortened.

Furthermore, even when automating the coating process, coating can be done without changing the position of the resonator, and one
Since only one coating operation is required, there is an advantage that the apparatus can be made smaller.

[Brief explanation of the drawing]

FIG. 1 is a front view of a resin-sealed resonator according to the present invention, FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1, FIG. 3 is a front view of the first step of the method of the present invention, and FIG. The figure is a sectional view taken along the IV-TV line in Fig. 3, Fig. 5 is a front view of the second step, and Fig. 6 is a - - in Fig. 5.
■ Line sectional view, Figure 7 is a front view of the 3rd process, Figure 8 is the 7th
It is a sectional view taken along the line ■-■ in the figure. DESCRIPTION OF SYMBOLS 1... Resonator, 2... Piezoelectric substrate, 3, 4... Electrode, 3a. 4a... Vibrating part (vibrating electrode), 30... Insulating resin, 31... Cavity, 40... Trowel, 50... Cavity forming material.

Claims (1)

[Claims] With a film made of a cavity forming material formed on the vibrating electrodes formed on the front and back surfaces of the piezoelectric substrate, the periphery of the piezoelectric substrate is sealed with an insulating resin, and at the time of the sealing or sealing. In a resin-sealed resonator in which a cavity is formed around a vibrating electrode by heating and absorbing the cavity-forming material into an insulating resin after cooling, the piezoelectric substrate is erected in a vertical direction. , a step of bringing a cavity-forming material applicator close to the upper end of the piezoelectric substrate that is standing upright, and supplying a drip of molten cavity-forming material from the applicator to the upper end of the piezoelectric substrate; A method for applying a cavity forming material for a resin-sealed resonator, comprising: solidifying or halving the drip in a state where it flows to a position covering the vibrating electrode.