JP3307225B2 - Manufacturing method of dielectric ceramic coaxial resonator element for microwave - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a dielectric ceramic coaxial resonator element for microwaves used in a high frequency region such as a microwave.

[0002]

2. Description of the Related Art In recent years, dielectric filters have been widely used in communication equipment utilizing electromagnetic waves in the microwave range, and dielectric ceramic coaxial resonator elements for microwaves have been widely used as main components of the dielectric filters. Have been.
At the same time, devices are becoming smaller, lighter and thinner, and miniaturization of dielectric ceramic coaxial resonator elements for microwaves, which are main components, is also progressing.

A dielectric ceramic coaxial resonator element for microwaves has a structure shown in FIG. In FIG. 4, 1 is an element, and 2 is a through hole.

Conventionally, as a method of forming an electrode on the element 1, the element 1 is randomly placed in an immersion basket, immersed in the electrode paste while rocking, and then pulled up. The electrode was formed on the entire surface of the element 1 including the through-hole 2 by removing using a method such as force, drying with hot air or the like, and then baking.

[0005]

However, according to the above method, when electrodes are formed on the element 1 using a high-viscosity electrode paste, the element 1 is randomly placed in an immersion basket and immersed. Although the electrode paste is applied to the outer surface of 1, the electrode paste is hardly permeated into the inside of the through hole 2, the electrode paste is not evenly applied to the inner surface of the through hole 2, and the electrode is attached after the electrode paste is baked. There are no places,
For this reason, the containment of the electromagnetic wave is insufficient, and the electric characteristics are deteriorated. In addition, when a low-viscosity electrode paste is used, the electrode formed in one application / bake may be thin or may not be applied. The desired electrode thickness satisfying the above conditions was formed. Furthermore, in order to cope with the miniaturization, light weight and thinness of the device using the element 1, the element 1 is also downsized, the inner diameter of the through hole 2 is reduced, and the penetration of the electrode paste into the through hole 2 is further deteriorated. In order to form an electrode having a predetermined thickness on the inner surface of the through hole 2,
Further, there is a problem that an electrode having a desired thickness must be formed by using a low-viscosity electrode paste and repeating the dip coating / baking operation many times.

The present invention provides a dielectric material for microwaves that can obtain an electrode thickness satisfying electrical characteristics by using a relatively high-viscosity electrode paste and performing dip coating and baking a few times. An object of the present invention is to provide a method for manufacturing a ceramic coaxial resonator element.

[0007]

In order to solve this problem, a method of manufacturing a dielectric ceramic coaxial resonator element for microwaves according to the present invention comprises mounting the element on a holding jig and forming a rod-shaped projection inside the through hole. In the inserted state, immersed in the electrode paste, pulled out the rod-shaped protrusion, sucked the electrode paste into the through-hole, inserted the rod-shaped protrusion again into the through-hole, removed excess electrode paste, and then removed the electrode paste tank. The intended purpose can be achieved by removing the element from the substrate and drying and baking to form an electrode.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of manufacturing a dielectric ceramic coaxial resonator element for microwave according to claim 1 of the present invention is as follows.
With the element mounted on the holding jig and the rod-shaped projection inserted into the through-hole of the element, immersed in an electrode paste tank, then pull out the rod-shaped projection and suction the electrode paste into the through-hole of the element to remove the electrode paste. After coating, the rod-shaped projections are inserted again into the through holes of the element to drive off excess electrode paste, and then the whole is taken out of the electrode paste tank. Then, after drying, the electrode paste is baked to form electrodes on the entire surface including the inner surface of the through hole of the element. According to this method, the electrode paste having a relatively high viscosity can be formed inside the through hole of the element. The electrode paste can be easily sucked, the electrode paste can be applied to the entire inner surface of the through hole, and the electrode thickness satisfying the electrical characteristics can be formed in a small number of times.

According to a second aspect of the present invention, the diameter of the rod-shaped projection is smaller than the inner diameter of the through-hole of the element by about 0.2 mm, and the tip is thinner than the center. Thus, when the rod-shaped projection is pulled out from the inside of the through hole of the element, the clearance between the rod-shaped projection and the element through hole is small, so that the inside of the through hole is close to a vacuum, and the electrode paste is strongly sucked into the inside of the through hole. Next, when the rod-shaped projection is inserted into the through hole again, the tip is thin, so that it can be smoothly inserted into the through hole, and the electrode paste inside the through hole is strongly pressed against the inner wall of the through hole of the element, and the uniform thickness is obtained. A coating can be formed.

According to a third aspect of the present invention, a spiral groove is formed on the surface of the rod-like projection, whereby the electrode paste is sucked into the through hole of the element and then the rod-like projection is inserted again. Then, a part of the electrode paste flows out toward the upper part of the through hole while rotating through the spiral groove of the rod-shaped projection. At this time, the electrode paste is pressed strongly against the inner wall surface of the through-hole, so that a uniform coating film is formed on the inner surface of the through-hole. The electrode paste held in the hole effectively functions to correct the coating film on the inner surface of the through hole.

According to a fourth aspect of the present invention, the rod-shaped projection is made of a non-rusting metal or a solvent-resistant resin, which is formed on the electrode paste to be used and on the inner surface of the through hole. This is to prevent foreign matter from being mixed into the coating film.

According to a fifth aspect of the present invention, there is provided an element
Held so that the surface having the through hole becomes the upper and lower surfaces, which inserts the rod-like protrusion from the upper surface side of the element, which is sucked into the through-hole when pulled out the rod-like protrusions were immersed in electrode paste tank This is because, when the rod-shaped projection is inserted into the through-hole again, the bubbles trapped together with the electrode paste thus obtained are easily discharged out of the system through the clearance.

According to a sixth aspect of the present invention, the entire jig is immersed in the electrode paste tank and the rod-like projection inserted into the through hole is moved up and down, thereby sucking into the inside of the through hole of the element. The electrode paste is repeatedly applied to the inner surface of the through hole. This utilizes the thixotropy of the relatively high-viscosity electrode paste to make it easier to suck the electrode paste into the through-hole and rub the electrode paste on the inner surface of the through-hole to make it more compatible with the inner surface. To make it better.

According to a seventh aspect of the present invention, the electrode paste is immersed in an electrode paste tank, and the electrode paste is sucked into the through hole.
Insert the rod-like projection into the through hole again and follow up the excess electrode paste.
After brewed, which gives a vibration to the upper, attached thereby rubbing strongly the electrode paste which is held by utilizing the vibration of a rod-like protrusion through hole surface between the through-hole inner surface and the rod-shaped projections At the same time, it is for removing air bubbles adsorbed on the wall surface and forming a uniform and defect-free coating film.

According to the invention of claim 8 of the present invention, the viscosity of the electrode paste used is higher than 500 mPa · s
An electrode paste having a viscosity range lower than 00 mPa · s is used, which defines a viscosity range that is easily sucked into the through-holes of the element and is suitable for forming a coating film having a predetermined thickness with a smaller number of application times. The viscosity range is determined.

According to a ninth aspect of the present invention, the electrode paste is used in a state where the electrode paste is heated to a temperature of 20 ° C. to 50 ° C., which does not volatilize a solvent contained in the electrode paste. In addition, the viscosity of the resin component contained therein is reduced to provide appropriate fluidity so that the resin component is easily sucked into the through hole of the element.

An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a perspective view of a jig according to an embodiment of the present invention, FIG. 2 is a perspective view of a rod-shaped projection, FIG. 3 is a view of an electrode coating process, and FIG. In FIG.
Reference numeral 1 denotes an element, 3 denotes a holding plate, 4 denotes a support portion of a bar-shaped protrusion, and 5 denotes a bar-shaped protrusion. In FIG. 2, reference numeral 6 denotes a groove provided on the surface of the rod-shaped projection 5.

(Embodiment 1) First, as shown in FIG.
A dielectric ceramic coaxial resonator element 1 (hereinafter, referred to as element 1) for microwaves having a width of 6 mm, a height of 8 mm, and an inner diameter of 2.0 mm of the through hole 2 is held by a holding plate 3 made of stainless steel. A rod-shaped projection 5 made of stainless steel and having an outer diameter of 1.8 mm is inserted into the through hole 2 (A). Next, with the element 1 attached to a jig, the element 1 is immersed in an electrode paste tank (not shown),
In order to improve the compatibility between the electrode paste and the surface of the element 1, the entire jig is rocked for a short time (B), and then the rod-like projection 5 is pulled out upward, and the electrode paste is sucked into the through hole 2 (C). ). After that, the rod-shaped projections 5 are inserted into the through holes 2 where the electrode paste is sucked again (D), and the excess electrode paste is removed, and the electrode paste is pressed on the inner surface of the through holes 2 to apply the electrodes. Next, after removing the entire jig from the electrode paste tank (E), the element 1 is removed from the jig (F), dried (G), and baked at a temperature of 800 ° C. (H). The electrodes formed on the upper and lower end surfaces of the device 1 were removed by polishing to obtain a finished product of the device 1 in which electrodes were formed on all side surfaces of the device 1 and inside the through holes 2 (I). The electrode paste used at this time is 500, 1000, 300 in advance.
Adjust the viscosity to 0.5, 8000, and 10000 mPa · s and use the whole electrode paste tank of 30.
The operation was performed while heating to a temperature of ° C. The results of evaluating the characteristics of the element 1 obtained as described above are shown in (Table 1).
The evaluation of the characteristics of the element 1 was performed based on the electrical QE value. Various symbols in the table indicate variations in the QE value.
Represents 6 to 10%, Δ represents 11 to 20%, and X represents 21% or more. The number of application is the required number of repetitions of the electrode application and baking work until the electric QE value becomes 5% or less. Table 2 shows the results of forming electrodes of the element 1 by the conventional dip coating method using the electrode paste.

[0019]

[Table 1]

[0020]

[Table 2]

As can be seen from (Table 1), 500 mPa ·
When the viscosity is low as in s, a large number of times of application and baking is required, but when the viscosity is high, an electrode satisfying the electric QE value of 5% can be formed with a small number of times. However, when the viscosity is higher than 10000 mPa · s, the electrode paste is not sucked into the through-hole 2, and the electrode is cut off due to uneven application of the electrode on the inner surface of the through-hole 2. Also, in the case of the conventional method shown in (Table 2), when the pressure is higher than 1000 mPa · s, the electrode paste hardly permeates into the through holes 2,
Even when the electrode penetrates, the electrode formed by baking has a problem that the thickness under the through-hole 2 becomes thick, the electrode surface is cracked, and the electric characteristics are deteriorated. Therefore, it is necessary to reduce the viscosity of the electrode paste and increase the number of repetitions of coating and baking.

(Embodiment 2) Inner diameter of through hole 2 is 2.0 mm
Is held by a holding plate 3 and has an outer diameter of 1.0, 1..
5, 1.8 and 2.0 mm rod-shaped projections 5 were inserted, the electrode paste was heated to 30 ° C., and the viscosity was 500 and 50.
Embodiment 1 using the one adjusted to 00 mPa · s
The electrodes were coated and baked in the same manner as described above, and the evaluation results are shown in (Table 3).

[0023]

[Table 3]

As apparent from (Table 3), 500 mP
In the case of a · s, when the rod-shaped projection 5 has an outer diameter smaller than 1.5 mm, the electrode paste infiltrates into the through-hole 2 by itself due to the large gap between the rod-shaped projection 5 and the through-hole 2. Although the rubbing effect is thin and requires the same number of application and baking times as the conventional method, the 1.8 mm has a relatively good result although the number of application and baking times is large.
In the case of 5000 mPa · s, the electrode paste is sucked into the through-hole 2 when the rod-shaped protrusion 5 has an outer diameter smaller than 1.5 mm, but the rubbing effect of the rod-shaped protrusion 5 is thin and the sucked excessive amount. This makes it difficult to remove the electrode paste, and the electrode paste gathers below the through-hole 2 at the time of baking to form an electrode having an extremely thick portion, and cracks or holes are formed on the electrode surface. But the outer diameter is 1.8mm
In the case of (1), an electrode satisfying the electric QE value of 5% can be formed with a small number of times. Further, in the case of 2.0 mm, regardless of the viscosity, all of the sucked electrode paste is expelled from the through-hole 2 and an electrode cannot be formed on the inner surface of the through-hole 2. From the above results, it can be seen that the dimensional difference between the rod-shaped projection 5 and the through hole 2 needs to be about 0.2 mm.

(Embodiment 3) Through-hole 2 having an inner diameter of 2.0 mm
Is mounted on a holding plate 3, and a rod-shaped projection 5 having an outer diameter of 1.8 mm is inserted into the through-hole 2, and 5000 mPa ·
Electrode application was performed under the following conditions using an electrode paste heated to 30 ° C. with a viscosity of s.

(1) The electrode paste is immersed in the electrode paste tank, and the inserted rod-shaped projection 5 is moved up and down to suck the electrode paste into the through hole 2.

(2) The rod-shaped protrusion 5 immersed in the electrode paste tank is pulled upward to suck the electrode paste.
Next, after inserting the rod-shaped projection 5 into the through-hole 2 again, the rod-shaped projection 5 is vibrated through the support portion 4 of the rod-shaped projection 5.

An electrode is applied to the inner surface of the through hole 2 by the above method, and dried and baked in the same manner as in the first embodiment. The evaluation results of the obtained element 1 are shown in Table 4.

[0029]

[Table 4]

As is clear from Table 4, an electrode capable of satisfying an electric QE value of 5% by a single application and baking under the above two conditions can be formed on the inner surface of the through hole 2. You can see what you can do. That is, in the case of (1), the electrode paste is repeatedly and strongly pressed against the inner surface of the through hole 2 by moving the rod-shaped protrusion 5 up and down.
In the case of (2), the rod-like projections 5 resonate with the vibration applied through the support portions 4 of the rod-like projections 5, and penetrate the electrode paste held between the rod-like projections 5 and the inner surface of the through hole 2. Hole 2
This is probably the result of rubbing strongly on the inner surface of the. In the above method, the thixotropic property of the electrode paste is increased by the vertical swing of the rod-shaped protrusion 5 or the vibration of the rod-shaped protrusion 5, and there is also an effect of removing bubbles remaining in the inner surface of the through hole 2 or the electrode paste. It was found that a smooth surface was obtained without pinholes due to bubbles on the formed electrode surface.

(Embodiment 4) Through-hole 2 having an inner diameter of 2.0 mm
2 is mounted on a holding plate 3, and a rod-shaped projection 5 having a groove 6 having an outer diameter of 1.8 mm, a width of 1.0 mm, and a depth of 0.2 mm formed on the surface of the through hole 2 shown in FIG. The rod-shaped projection 5 is pulled out while being inserted and immersed in the electrode paste tank, and the electrode paste is sucked into the through-hole 2.
The rod-shaped projections 5 were inserted into the substrate to remove excess electrode paste, and then dried and baked under the same conditions as in the first embodiment. The electrode paste used at this time was heated to 30 ° C. at a viscosity of 5000 mPa · s. Table 5 shows the evaluation results of the obtained device 1.

[0032]

[Table 5]

As is clear from Table 5, the electric QE value of 5 was obtained with a small number of application and baking times of 2 or less.
% Of the electrode is formed on the inner surface of the through-hole 2. It was also found that the electrode surface obtained in the same manner as in Embodiment 4 could provide a smooth electrode without pinholes due to bubbles. This is because the electrode paste sucked into the through hole 2
When the rod-shaped projection 5 is inserted again, it is extruded toward the upper and lower surfaces of the through-hole 2, and when flowing out toward the upper surface thereof, the electrode paste is swirled through the groove 6 of the rod-shaped projection 5 on the inner surface of the through-hole 2. It is considered that this is due to the fact that the electrode paste held in the groove 6 corrects the surface applied to the inner surface of the through hole 2 when the element 1 is strongly pressed and the element 1 is taken out from the jig. Further, it is found that the electrode paste and the air bubbles trapped in the inner surface of the through hole 2 are also removed from the system through the groove 6 to obtain a smooth electrode.

(Embodiment 5) Through-hole 2 having an inner diameter of 2.0 mm
Is mounted on a holding plate 3 and immersed in an electrode paste tank with a rod-shaped projection 5 having an outer diameter of 1.8 mm inserted into the through-hole 2, and then the rod-shaped projection 5 is pulled out to remove the electrode paste from the through-hole. After sucking into the inside of 2, an electrode was applied by a method of inserting the rod-shaped protrusion 5 into the through hole 2 again, and drying and baking were performed under the same conditions as in the first embodiment. The electrode paste used at this time had a viscosity of 5,000 mPa · s and 8000 mPa · s at room temperature (20 ° C.), and the electrode paste tanks were room temperature (20 ° C.), 30 ° C., 40 ° C., and 50 ° C., respectively.
Electrode coating was performed under the condition heated to ° C. Table 6 shows the evaluation results of the device 1 obtained under these conditions.

[0035]

[Table 6]

As is clear from Table 6, the 8000 mPa · s electrode paste having a high viscosity and hard to be sucked at a temperature near room temperature can be applied to a small amount by heating to 50 ° C.
It can be seen that an electrode satisfying the electric QE value of 5% can be formed by the number of times of printing. This is presumably because the resin component contained in the electrode paste softens and the fluidity increases. It is understood that heating to a temperature at which the solvent component contained in the electrode paste is not volatilized is an effective means when using an electrode paste having a relatively high viscosity.

In each embodiment of the present invention, a rod-shaped projection 5 having an outer diameter of 1.8 mm is inserted into a device 1 having a length of 6 mm, a width of 8 mm and a height of 8 mm and having a through hole 2 having an inner diameter of 2.0 mm. The electrode was applied in this manner, but the same effect can be obtained even if the inner diameter of the through-hole 2 is different by using the rod-shaped projection 5 which is smaller than the inner diameter of the through-hole 2 by about 0.2 mm. Although the holding plate 3 and the bar-shaped projections 5 are made of stainless steel, they may be made of a solvent-resistant resin. Further, as the electrode paste, any of silver, copper, platinum, palladium and the like used as electrodes of ceramic electronic components can be used.

[0038]

As described above, when electrodes are formed on the entire surface of the dielectric ceramic coaxial resonator element for microwave of the present invention, the electrodes are immersed in the electrode paste tank with the rod-shaped projections inserted into the through holes. Then, after extracting the rod-shaped projections and sucking the electrode paste into the through-holes, the rod-shaped projections are inserted again into the through-holes to form electrodes capable of satisfying the characteristics with a small number of repetitions of application and baking operations. be able to.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a perspective view of the rod-shaped protrusion.

FIG. 3 is a view showing an electrode coating process of the same element.

FIG. 4 is a perspective view of an element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Coaxial resonator element 2 Through-hole 3 Holding plate 4 Support part of rod-shaped projection 5 Rod-shaped projection 6 Groove part

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01P 11/00 H01P 7/04 H01P 1/205

Claims (9)

(57) [Claims] 1. A holding jig for holding a dielectric ceramic coaxial resonator element for microwaves having a through hole (hereinafter referred to as an element), and a rod-shaped projection inserted into the through hole of the element. With the element held by a jig, the rod-shaped projection is inserted into the through-hole, and immersed in an electrode paste tank. Then, the rod-shaped projection is pulled out, the electrode paste is sucked into the through-hole of the element, and the inner surface is coated. After inserting the rod-shaped protrusion into the through hole of the element again to expel excess electrode paste, remove the element from the electrode paste tank, then remove the element from the holding jig, dry it, and bake the electrode paste. Forming a dielectric ceramic coaxial resonator element for microwaves. 2. The dielectric ceramic for microwave according to claim 1, wherein the diameter of the rod-shaped projection is smaller than the inner diameter of the through hole of the element by about 0.2 mm, and the tip of the rod is thinner than the center. A method for manufacturing a coaxial resonator element. 3. The method for manufacturing a dielectric ceramic coaxial resonator element for microwave according to claim 1, wherein a spiral groove is formed on the surface of the rod-shaped projection. 4. The method for manufacturing a dielectric ceramic coaxial resonator element for microwave according to claim 1, wherein the material of the rod-shaped projection is a non-rusting metal or a solvent-resistant resin. 5. A surface having a through hole of an element is an upper and lower surface.
Method of manufacturing a microwave dielectric ceramic coaxial resonator element according to claim 1 as held, characterized by inserting the rod-like protrusion from the upper surface side of the device. 6. The method for manufacturing a dielectric ceramic coaxial resonator device for microwave according to claim 1, wherein the rod-shaped projection inserted into the through hole is moved up and down to suck the electrode paste into the through hole of the device. . 7. An electrode paste is sucked into the through-hole and re-soldered.
Follow Excess electrode paste inserting fine rod-like projections into the through-hole
2. The method for manufacturing a dielectric ceramic coaxial resonator element for microwave according to claim 1, wherein the electrode paste which has been vibrated and sucked is applied to the inner surface of the through hole of the element. 8. The viscosity of the electrode paste is 500 mPa · s.
2. The method of manufacturing a dielectric ceramic coaxial resonator device for microwave according to claim 1, wherein an electrode paste having a higher range and lower than 8000 mPa · s is used. 9. The method of manufacturing a dielectric ceramic coaxial resonator device for microwave according to claim 1, wherein the electrode paste is used while keeping the temperature at a temperature of 20 ° C. to 50 ° C.