JP3996710B2 - Electrode formation method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrode forming method for forming an electrode layer in an appropriate shape on the surface of a dielectric block in order to constitute a dielectric filter or the like.
[0002]
[Prior art]
In recent years, a dielectric filter has been widely used as a band-pass filter of a microwave band such as a cellular phone. An example of the structure of this dielectric filter is that a cylindrical or prismatic ceramic dielectric block is provided with a through hole in the axial direction, and the inner surface of this through hole and the one other than the one end face where the through hole of the dielectric block is opened. An electrode layer is provided on the outer surface, and island portions as input / output electrodes are formed on the electrode layer on the outer surface of the dielectric block.
[0003]
As an example, these electrode layers are formed by applying a conductive paste in an appropriate shape to the outer surface of the dielectric block by screen printing and baking it. As another example, after an electrode layer is formed on the entire outer surface of the dielectric block, unnecessary portions of the electrode layer are appropriately ground to form an electrode layer having a predetermined shape.
[0004]
[Problems to be solved by the invention]
In the method of forming the electrode layer by applying the above-described conventional conductive paste by screen printing and baking it, it is difficult to obtain the dimensional accuracy of the shape of the electrode layer, and the screen is provided for each plane of the dielectric block. Printing has to be performed, and many processes are required for an electrode layer provided on each of many surfaces.
[0005]
In the method of appropriately grinding the electrode layer provided on the entire outer surface of the dielectric block, as one means for grinding the electrode layer, a trimming mask is provided on the electrode layer, and abrasive grains are provided on the trimming mask. In some cases, the electrode layer is ground in accordance with the shape of the opening window provided in the trimming mask. Here, the electrode layer formed by the electroless plating method can be relatively easily ground by spraying abrasive grains. However, the electrode layer formed by this electroless plating method has insufficient adhesion to the dielectric block and is likely to be peeled off by soldering or the like. In addition, since the electrode layer formed by baking the conductive paste at a temperature of 800 to 860 degrees has extremely high adhesiveness to the dielectric block and the adhesiveness of silver is strong, in the method by spraying abrasive grains, In addition, it is difficult to grind, and it is difficult to obtain processing accuracy, and it is easy to damage the dielectric block itself due to excessive spraying of abrasive grains at the time of grinding, and there is a possibility that electrical characteristics may be affected. Further, the trimming mask is extremely worn and needs to be frequently replaced, resulting in a high manufacturing cost.
[0006]
The present invention has been made in view of the circumstances of the prior art, and an object thereof is to provide an electrode forming method capable of forming an electrode layer having good workability and high adhesion at low cost.
[0007]
[Means for Solving the Problems]
In order to achieve this object, the electrode forming method of the present invention includes a step of providing a conductive paste on the surface of a dielectric block, a step of pre-baking this conductive paste to form an electrode layer, and an electrode by this pre-baking A step of spraying abrasive grains on the layer and grinding to a predetermined shape; and a step of subjecting the electrode layer by temporary baking to a main baking; a nozzle outlet for spraying the abrasive grains from the predetermined shape to be ground The tip of the nozzle is formed to be stretchable and elastically urged toward the tip, and the tip of the nozzle is elastically biased to the electrode layer by pre-baking. The abrasive grain spray position is moved relative to the dielectric block .
[0008]
Then, the dielectric block may be rotated to move the abrasive grain spray position relative to the dielectric block so that the electrode layer formed by the preliminary baking is ground into a predetermined shape .
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a process diagram of a first embodiment of an electrode forming method according to the present invention. FIG. 2 is a cross-sectional view of a main part in which nozzles for spraying abrasive grains are disposed facing each other on an electrode layer formed by temporary baking formed on a dielectric block. FIG. 3 is a cross-sectional view taken along the line AA in FIG. 2, and is a cross-sectional view of a nozzle outlet of the nozzle that blows the abrasive flow. FIG. 4 is a cross-sectional view of an essential part of the electrode layer ground by spraying abrasive grains. FIG. 5 is a plan view of an essential part of an electrode layer ground by spraying abrasive grains.
[0010]
First, the ceramic dielectric block 10 is dipped (immersed) in a conductive paste such as silver paste or silver and palladium paste, and the conductive paste is provided on the entire outer surface of the dielectric block 10 with a film thickness of 20 to 25 μm. (Step 1). Instead of this dipping, a conductive paste may be appropriately provided on the entire outer surface of the dielectric block 10 or a necessary portion by coating or screen printing.
[0011]
Next, the dielectric block 10 provided with the conductive paste on the outer surface is heated and raised from room temperature to 400 to 650 degrees (Celsius) in about 30 minutes, held at 400 to 650 degrees for about 10 minutes, and then The temperature is lowered to room temperature by natural heat dissipation. The glass frit of the constituent elements of the conductive paste melts at the temperature of 400 to 650 degrees. And by this heating, an electrically conductive paste hardens | cures and the electrode layer 12 by temporary baking is formed (process 2). In the electrode layer 12 by this pre-baking, the glass frit which is a component of the conductive paste is not sufficiently dissolved in the dielectric block 10 and the stickiness of silver is small. Therefore, the adhesion force of the electrode layer 12 by temporary baking to the dielectric block 10 is not so large.
[0012]
And the nozzle 24 is arrange | positioned facing the electrode layer 12 by this temporary baking, and abrasive grains, such as ceramic powder and metal powder, are sprayed from this nozzle 24 by a dry type or a wet (sand blast method). As shown in FIG. 3, the nozzle 24 has a jet outlet formed so as to coincide with a predetermined shape 26 to be ground. Therefore, as shown in FIG. 5, the electrode layer 12 by temporary baking is ground into a predetermined shape 26 (step 3). Here, when grinding the electrode layer 12 by temporary baking, a trimming mask is not used as in the prior art.
[0013]
Further, the dielectric block 10 is heated again and raised from room temperature to 800 to 860 degrees (Celsius) in about 1 hour, held at this 800 to 860 degrees for about 10 minutes, and then lowered to room temperature by natural heat dissipation. . The temperature of 800 to 860 degrees is instructed by the manufacturer of the conductive paste as the baking temperature. By this reheating, the electrode layer 12 by temporary baking is further cured, and an electrode layer by main baking is formed (step 4). In this main baking, the glass frit of the conductive paste is sufficiently dissolved in the dielectric block 10 to have high adhesion, and the silver is also highly sticky.
[0014]
Therefore, by grinding the electrode layer 12 by temporary baking, the electrode layer 12 can be processed relatively easily and with high accuracy, and then the main baking can form an electrode layer with high adhesion. Therefore, the electrode layer can be easily and accurately formed, and the electrode layer is not peeled off by soldering. Furthermore, since the electrode layer 12 is ground without using a trimming mask, the trimming mask is not expensive and can be manufactured at a lower cost.
[0015]
Next, a second embodiment of the electrode forming method of the present invention will be described with reference to FIGS. FIG. 6 shows a first nozzle for forming an island-shaped electrode layer and a ground shape thereof, (a) is a sectional view of a jet nozzle of the first nozzle, and (b) is a shape of the ground shape. It is a top view. FIG. 7 shows a second nozzle for forming an island-shaped electrode layer and a ground shape thereof, (a) is a sectional view of a jet nozzle of the second nozzle, and (b) is a shape of the ground shape. It is a top view. FIG. 8 is a plan view of a shape in which the electrode layers are overlapped and ground by the first and second nozzles.
[0016]
In the input / output electrodes of the dielectric filter, the island-shaped electrode layer may be provided by grinding the electrode layer into a square shape, for example. As a grinding method in such a case, first, as shown in FIG. 6B, the first nozzle 24a having a U-shaped jet outlet as shown in FIG. The predetermined shape 26a is ground in a shape. Next, as shown in FIG. 7 (a), the second nozzle 24b having an I-shaped jet outlet has a predetermined shape 26b in an I-shape as shown in FIG. Is ground. Then, the first and second nozzles 24a and 24b are disposed at the same position, and the electrode layer 12 by temporary baking is sequentially stacked and ground, so that the electrode layer 12 by temporary baking is applied to the electrode layer 12 by temporary baking as shown in FIG. The predetermined shape 26 having a letter shape is ground. The shape of the island-shaped electrode layer 28 may be any shape, and the shape of the jet port in which the predetermined shape 26 to be ground for forming the island-shaped electrode layer 28 is appropriately divided. A plurality of nozzles may be used in an overlapping manner.
[0017]
Subsequently, a third embodiment of the electrode forming method of the present invention will be described with reference to FIG. FIG. 9 is a diagram for explaining that the nozzle is movable in the X and Y planes relative to the dielectric block.
[0018]
In the first and second embodiments, it is assumed that the electrode layer 12 by pre-baking is ground into a predetermined shape depending on the shape of the area where abrasive grains are sprayed from the nozzle 24. However, when the area to which the abrasive grains are sprayed from the nozzle 24 is smaller than the predetermined shape 26 to be ground, or when the predetermined shape 26 to be ground is long, as shown in FIG. On the other hand, the nozzle 24 is relatively movable in a plane in the X and Y directions while maintaining a predetermined interval, and the nozzle 24 is relatively moved in correspondence with the predetermined shape 26 to be ground. By this method, the electrode layer 12 can be ground by temporary baking according to a large area or a long predetermined shape 26.
[0019]
Even in the third embodiment, since the electrode layer 12 is preliminarily baked with relatively low adhesion, the workability is good as in the first embodiment, and the main baking is performed after the grinding process. An electrode layer with high adhesion can be formed. And in the thing where the spraying area of the nozzle 24 is small, it is possible to use the abrasive grains more effectively than in the case where the nozzle 24 is sprayed over a large area, and the grinding apparatus can be greatly downsized, Economical. Note that at least one of the nozzle 24 and the dielectric block 10 may be moved, and this movement control is performed by appropriately controlling the work table or the like by computer control (XYθZ axis control) based on pre-programmed data. Just do it.
[0020]
An example of the nozzle used in the third embodiment is shown in FIG. FIG. 10 is a cross-sectional view showing a nozzle having a narrow tapered shape at the front end side of the ejection port. In the nozzle 24 shown in FIG. 10, since the tip end side of the spout is tapered, the ejected abrasive grains are concentrated in a narrow area on the electrode layer 12, and the electrode layer is locally baked. 12 can be ground and fine processing is possible.
[0021]
Furthermore, FIG. 11 shows another example of the nozzle used in the third embodiment. FIG. 11 is a cross-sectional view showing a nozzle whose tip is extendable. In the nozzle 24 shown in FIG. 11, a telescopic tube 30 is provided at the distal end so as to be movable in the axial direction and so as not to fall off, and is elastically biased by a spring 32 at the distal end. ing. The dielectric block 10 is relatively moved while the abrasive grains are ejected from the nozzle 24 in a state where the extensible tip is elastically contacted with the electrode layer 12 by temporary baking and is tilted slightly. The ejected abrasive flow flows out through a gap opened by tilting after grinding the electrode layer 12 by temporary baking. Since the abrasive flow flows out only to one side, the electrode layer 12 can be sharply ground by temporary baking on the side where the tip is elastically contacted.
[0022]
Further, a fourth embodiment of the electrode forming method of the present invention will be described with reference to FIG. FIG. 12 is a diagram for explaining that a predetermined shape is ground on the outer peripheral surface by rotating a cylindrical dielectric block with respect to the nozzle.
[0023]
In the fourth embodiment of FIG. 12, an electrode layer 42 is provided by pre-baking on the outer surface of the cylindrical dielectric block 40, and the nozzle 24 is disposed facing the outer peripheral curved surface of the electrode layer 42. The curved electrode layer 42 can be easily ground by rotating the dielectric block 40 around the axis 44 while spraying abrasive grains from the nozzle 24. In the fourth embodiment, if the nozzle 24 or the dielectric block 40 is relatively movable in the direction of the axis 44, the electrode layer 42 by temporary baking can be formed in an island shape by appropriate movement control. is there.
[0024]
Furthermore, a fifth embodiment of the electrode forming method of the present invention will be described with reference to FIG. In FIG. 13, the prismatic dielectric block is rotated around the axis with respect to the nozzle, and the nozzle is moved in a direction orthogonal to the axis to grind a predetermined shape across two adjacent surfaces. FIG.
[0025]
In the fifth embodiment of FIG. 13, a nozzle 24 is disposed on the outer surface of a prismatic dielectric block 50 so as to face the electrode layer 52 by pre-baking, and the abrasive block is sprayed with abrasive grains from the nozzle 24. 50 is rotated about the axis 54, and the nozzle 24 is moved in a direction orthogonal to the axis 54, and the distance between the tip of the nozzle 24 and the dielectric block 50 is controlled to be substantially constant. In this way, the electrode layer 52 is easily ground across the two surfaces. Here, since the predetermined shape 26 to be ground is provided long around the axis 54 of the dielectric block 50, it is not necessary to move the nozzle 24 and the dielectric block 50 relatively in the direction of the axis 54. However, if the predetermined shape 26 to be ground is provided in a direction that crosses the axis 54 obliquely, or if the electrode layer 52 is formed in an island shape, the nozzle 24 and the dielectric block 50 are relative to each other in the axis 54 direction. It may be appropriately controlled so as to be freely movable. In the fifth embodiment, the electrode layer 52 is not limited to be ground over two adjacent surfaces, but the electrode layer 52 may be ground over three or more surfaces.
[0026]
【The invention's effect】
As described above, according to the electrode forming method of the present invention, the following special effects can be obtained.
[0027]
In the electrode forming method according to the first aspect, since the electrode layer by pre-baking in a state of low adhesion is ground into a predetermined shape, the workability is excellent and dimensional accuracy is easily obtained. And by baking this after grinding, it can be set as the electrode layer excellent in adhesiveness, and peeling does not arise by soldering etc. Furthermore, since the nozzle outlet for spraying abrasive grains is smaller than the predetermined shape to be ground, the abrasive grains can be used more effectively and the grinding equipment It can be downsized and is economical. In addition, the tip of the nozzle is formed to be extendable and elastically biased toward the tip, and the position of the abrasive grain spraying position is made in a state where the expandable tip of the nozzle is elastically contacted with the electrode layer by temporary baking. Since it is made to move relative to the dielectric block, the ejected abrasive flow flows out from the gap opened by tilting after grinding the electrode layer by temporary baking, and the abrasive flow is directed to one side. Only spilled. As a result, the electrode layer can be sharply ground by temporary baking on the side where the tip is elastically contacted.
[0028]
In the electrode forming method according to claim 2, by rotating the dielectric block, the electrode layer provided over a plurality of adjacent surfaces or the electrode layer provided on the curved surface is formed in one step. Can be ground. Therefore, it is excellent in working efficiency for grinding an electrode layer provided on a plurality of surfaces or curved surfaces.
[Brief description of the drawings]
FIG. 1 is a process diagram of a first embodiment of an electrode forming method according to the present invention.
FIG. 2 is a cross-sectional view of a main part in which nozzles for spraying abrasive grains are arranged facing each other on an electrode layer formed by temporary baking formed on a dielectric block.
FIG. 3 is a cross-sectional view taken along line AA in FIG. 2 and is a cross-sectional view of a nozzle outlet of a nozzle that blows out an abrasive flow.
FIG. 4 is a cross-sectional view of a main part of an electrode layer ground by spraying abrasive grains.
FIG. 5 is a plan view of an essential part of an electrode layer ground by spraying abrasive grains.
FIG. 6 shows a first nozzle for forming an island-shaped electrode layer and a ground shape thereof, (a) is a sectional view of a jet nozzle of the first nozzle, and (b) is a shape of the ground shape. It is a top view.
FIG. 7 shows a second nozzle for forming an island-shaped electrode layer and a ground shape thereof, (a) is a sectional view of a jet nozzle of the second nozzle, and (b) is a shape of the ground shape. It is a top view.
FIG. 8 is a plan view of a shape in which electrode layers are overlapped and ground by first and second nozzles.
FIG. 9 is a diagram for explaining that the nozzle is movable relative to the dielectric block in a plane in the X and Y directions.
FIG. 10 is a cross-sectional view showing a nozzle having a narrow tapered shape at the tip end side of the ejection port.
FIG. 11 is a cross-sectional view showing a nozzle having a tip that can be extended and contracted.
FIG. 12 is a diagram for explaining that a cylindrical dielectric block is rotated with respect to a nozzle to grind a predetermined shape on an outer peripheral surface.
FIG. 13 shows that a prismatic dielectric block is rotated about its axis with respect to the nozzle and the nozzle is moved in a direction perpendicular to the axis so as to grind a predetermined shape across two adjacent surfaces. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10, 40, 50 Dielectric block 12, 42, 52 Electrode layer by temporary baking 24 Nozzle 26 Predetermined shape to be ground 28 Island-like electrode layer 30 Stretch tube 32 Spring 44, 54 Axis

Claims (2)

A step of providing a conductive paste on the surface of the dielectric block, a step of calcining this conductive paste to form an electrode layer, a step of spraying abrasive grains on the electrode layer by this calcining and grinding to a predetermined shape, And a step of subjecting the electrode layer by temporary baking to a main baking, and a nozzle outlet for spraying the abrasive grains is smaller than the predetermined shape to be ground, and the tip of the nozzle is formed to be extendable. In addition, the tip of the nozzle is elastically urged toward the tip side, and the abrasive grain spraying position is relative to the dielectric block in a state where the tip end of the nozzle is inclining and elastically contacting the electrode layer by temporary baking. An electrode forming method characterized in that the electrode is moved in a moving manner. 2. The electrode forming method according to claim 1, wherein the dielectric block is rotated to move the abrasive grain spraying position relative to the dielectric block, so that the electrode layer formed by the preliminary baking is formed into a predetermined shape. An electrode forming method comprising grinding .

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