JP2657460B2 - Manufacturing method of dielectric filter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a method of manufacturing a laminated chip type dielectric filter used as a circuit element of a mobile communication device in a UHF band or a microwave band.

2. Description of the Related Art A laminated chip type dielectric filter basically has the following configuration. A plurality of dielectric sheets are laminated and joined to form an integrated laminated substrate, and a plurality of strip-shaped resonance electrodes are formed in parallel on predetermined joining surfaces of the plurality of dielectric sheets. Ground electrodes are formed on the front and back surfaces of the laminated substrate. One end of each band-shaped resonance electrode is connected to the ground electrode in various forms, and the other end of each band-shaped resonance electrode is an open end. Further, various types of input / output electrodes are disposed in association with predetermined portions of the band-shaped resonance electrode. The frequency characteristic of this type of filter changes depending on the length of the band-shaped resonance electrode. Conventional dielectric filters are of a type in which the length of the band-shaped resonance electrode incorporated between the dielectric sheets cannot be finely adjusted after manufacture (Japanese Patent Publication No. 61-19122), and a band-shaped resonance electrode manufactured after manufacture. There is a type in which the length of the electrode can be finely adjusted (JP-A-3-196701 and JP-A-5-110305). In the latter type, in which the length of the resonance electrode can be fine-tuned, both ends of each resonance electrode sandwiched between the dielectric sheets reach both side surfaces of the multilayer substrate, and both side surfaces of the multilayer substrate even after manufacturing. The length of the internal resonance electrode can be shortened by appropriately deleting the predetermined portion of. Specifically, the configuration disclosed in Japanese Patent Application Laid-Open No. 3-196701 has a configuration as shown in FIG. As shown in the figure, a laminated substrate is composed of two dielectric sheets 1a and 1b. Lower surface of dielectric sheet 1a and dielectric sheet 1b
Earth electrodes 5 and 6 are entirely formed on the upper surface of. On the upper surface of the lower dielectric sheet 1a, three band-shaped resonance electrodes 2, 3, and 4 are formed in parallel. Both ends of each of the resonance electrodes 2, 3, and 4 reach both ends of the dielectric sheet 1a. One end of each of the resonance electrodes 2 and 4 is connected to a side ground electrode 2 formed on one side of the dielectric sheet 1a.
a, 4a are connected to the lower surface ground electrode 5.
One end of the center resonance electrode 3 is connected to the lower surface ground electrode 5 via a side surface ground electrode 3a formed on the opposite side surface of the dielectric sheet 1a. The opposite ends (open ends) 2b, 3 of the respective resonance electrodes 2, 3, 4 not connected to the ground
b and 4b are exposed at the boundary between the two sheets 1a and 1b on the side surface of the laminated substrate. By removing the exposed portion, the length of the resonance electrode can be appropriately reduced. Note that reference numeral 7 in the figure is an input / output electrode. However, FIG.
When the filter shown in (1) is manufactured, side earth electrodes 2a, 3a, and 4a are locally formed on both side surfaces of the laminated substrate by screen printing or the like. Forming a partial metal film on the side surface of a laminated substrate forming a flat rectangular parallelepiped block in this way has been a very time-consuming and complicated operation in the manufacturing process. This has hindered the productivity of this type of filter. Japanese Patent Laid-Open No. 5-
Japanese Patent Publication No. 110305 has a configuration as shown in FIG. The laminated substrate 1 is composed of the two dielectric sheets 1a and 1b. Ground electrodes 5 and 6 are formed entirely on the lower surface of the dielectric sheet 1a and the upper surface of the dielectric sheet 1b. On the upper surface of the lower dielectric sheet 1a, three band-shaped resonance electrodes 2, 3, and 4 are formed in parallel. Both ends of each of the resonance electrodes 2, 3, and 4 are connected to the dielectric sheet 1a.
Reach both ends of the. One end of each of the resonance electrodes 2 and 4 is connected to upper and lower earth electrodes 5 and 6 via side earth electrodes 2 a and 4 a attached to the inner surface of an edge through hole 8 formed on one side of the laminated substrate 1. ing. One end of the central resonance electrode 3 is connected to upper and lower earth electrodes 5 and 6 via side earth electrodes 3 a attached to the inner surface of an edge through hole 8 formed on the opposite side surface of the laminated substrate 1. . The opposite ends (open ends) 2b, 3b, 4b of the respective resonance electrodes 2, 3, 4 which are not connected to the ground are exposed at the boundary between the two sheets 1a, 1b in the side plane portion of the laminated substrate 1. Become. By grinding the side plane portion, the length of the resonance electrode can be appropriately reduced. In addition,
Reference numeral 7 in the figure is an input / output electrode. However, in the prior art shown in FIG. 10, since the side surface ground electrodes 2a, 3a, and 4a are formed by applying the through-hole technology, FIG.
It can be said that the mass production is higher than that of. However, it is difficult to form the electrode film uniformly on the inner surface of the through hole, especially as the hole diameter increases, and the process becomes complicated. Therefore, it has not yet reached a satisfactory level in terms of mass productivity. Further, there are the following disadvantages common to those shown in FIGS. That is, since the open ends 2b, 3b, 4b of the resonance electrodes 2, 3, 4 that are not connected to the ground are exposed on the outer surface of the laminated substrate, the shielding properties are poor. Therefore, when this dielectric filter is mounted on a circuit board at a high density together with other circuit elements, the characteristics are likely to change due to the influence of the distributed capacitance depending on the distance between components adjacent to the filter. SUMMARY OF THE INVENTION The present invention has been made in view of the above background, and its object is to make it easy to manufacture, to easily form a side ground pattern, and to easily set the length of a resonance electrode. Another object of the present invention is to provide a manufacturing method capable of manufacturing a dielectric filter having high mass productivity and excellent shielding properties.

In order to achieve the above object, a method of manufacturing a dielectric filter according to the present invention uses a plurality of dielectric sheets larger than the shape of a laminated dielectric filter to be manufactured. On the surface of some of the plurality of dielectric sheets, a conductor film constituting a ground electrode or a resonance electrode is formed, and the dielectric sheet and the conductor film on which the conductor film is formed are formed. Dielectric sheets that are not formed are laminated in a predetermined order to form a laminated substrate, and a predetermined position of the laminated substrate is cut to separate the individual filter elements, and then a conductor is provided on the side of the filter element. A method for manufacturing a dielectric filter, comprising forming an electrode film and forming a side surface ground electrode and an input / output electrode on a side surface thereof, wherein a position of the plurality of dielectric filters on the large dielectric sheet is formed. Between them, there is provided a cutting margin of a predetermined width not used for the final product (“E area” in the embodiment), and a plurality of dielectric filter forming areas are traversed on the surface of the predetermined large dielectric sheet. A plurality of strip-shaped electrode patterns having the same width are formed in parallel, and are machined to a predetermined position including a cutting position (corresponding to “cutting line D” in the embodiment) with respect to the laminated substrate in a direction orthogonal to the electrode pattern. By forming a through hole (corresponding to the "round hole A" in the embodiment) to divide the continuous strip-shaped electrode pattern into a resonance electrode, and then cutting the dielectric sheet at the cutting position, the separation is performed. A concave portion based on the through hole is formed on a side surface of the filter element, and a resonance electrode having a predetermined length is provided (claim 1). Preferably, at least two cuts are made at a predetermined position including a cutting position (corresponding to the cutting line C in the embodiment) with respect to the laminated substrate parallel to the strip-shaped electrode pattern with respect to one side of one dielectric filter formation region. A through hole (corresponding to “round hole B” in the embodiment) is formed. Next, by cutting the dielectric sheet at the cutting position, a concave portion based on the through hole is formed on a side surface of the separated filter element body where the resonance electrode is not exposed. Subsequently, by performing a printing process of a conductor on a portion located on the same surface except for the concave portion with respect to the side surface of the filter element body, the ground electrode and the input / output electrode are connected through the concave portion. That is, they are formed in a separated state (claim 2). Further, it is preferable that the length of each band-shaped resonance electrode is set to a predetermined value by the amount of substrate removal when forming each of the concave portions located at one end of the band-shaped resonance electrode (claim 3).

The portions other than the concave portion on both side surfaces of the laminated substrate are located on the same plane, and the concave portion is recessed from the surface. Therefore, when the side surface is solid printed, the conductive film is applied only to the same plane portion, that is, the portion other than the concave portion, and the side surface ground electrode is formed. The formation of the side-surface ground electrode can be performed in the same process as the formation of the electrode film on the entire side surface, and is extremely simple. Then, the side surface ground electrode and one end of the resonance electrode are separated by the concave portion, and the separated one end becomes the open end. The open end is exposed at the boundary between the two dielectric sheets in the concave portion. By removing the exposed portion, the length of the resonance electrode can be reduced. However, since the exposed open end is recessed into the inside of the concave portion, it has much better shielding properties than the case where it is exposed on the outer surface.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the method for manufacturing a dielectric filter according to the present invention will be described below in detail with reference to the accompanying drawings. First, an example of a dielectric filter manufactured by implementing the method of the present invention will be described. As shown in FIGS. 1 to 3, a plurality of dielectric sheets are laminated and bonded to form a flat rectangular parallelepiped laminated substrate 1. A surface ground electrode 6 is formed almost entirely on the surface of the laminated substrate 1.
Two surface input / output electrodes 7a are formed locally.
Similarly, the back surface ground electrode 5 is formed almost entirely on the back surface of the laminated substrate 1, and two back surface input / output electrodes 7b are locally formed. Three band-shaped resonance electrodes 2, 3, and 4 are formed in parallel on predetermined bonding surfaces of a plurality of dielectric sheets constituting the laminated substrate 1. Both ends of each of the resonance electrodes 2, 3, 4 reach the upper and lower sides of the laminated substrate 1. Exposed upper end portions of the resonance electrodes 2 and 4 on the upper surface of the laminated substrate 1 are arc-shaped concave portions 21 and 2 partially removed.
1 is formed. An upper surface ground electrode 9a is formed on a portion of the upper surface of the laminated substrate 1 excluding the two concave portions 21 and 21. An exposed portion of the lower end of the resonance electrode 3 on the lower surface of the laminated substrate 1 is an arc-shaped concave portion 3 partially removed.
1 is formed. A lower surface ground electrode 9b is formed on the lower surface of the laminated substrate 1 except for the concave portion 31. The lower ends of the resonance electrodes 2 and 4 are connected to the lower surface ground electrode 9b. The upper end of the resonance electrode 3 is connected to the upper surface ground electrode 9a. Further, the cut amount (distance from the side surface to the innermost point) of the concave portion 31 is longer than that of the concave portion 21. As a result, the length of the center resonance electrode 3 is shorter than the length of the resonance electrodes 2 and 4 on both sides. The lengths of the resonance electrodes 2 and 4 on both sides are the same.
21 because they determine the position of the open end. On each of the left and right side surfaces of the laminated substrate 1, a pair of small concave portions 51 and 52 formed by locally removing the substrate are provided at predetermined positions. An electrode film is formed on the left and right side surfaces of the laminated substrate 1 except for the concave portions 51 and 52, and the concave portions 51 and 52 of the electrode films are formed.
Are the input / output electrodes 7c on the left and right sides, and the other large area is the ground electrode 9c on the left and right sides. As shown, the input / output electrodes 7a and 7b on the front and back surfaces and the input / output electrodes 7c on the left and right side surfaces
And are electrically connected. The layout of the input / output electrodes is of the electric field coupling type, and is electromagnetically coupled to the intermediate portions of the resonance electrodes 2 and 4, respectively. Of course, the front and rear surfaces, and the top, bottom, left and right ground electrodes are all electrically connected. As is apparent from the above description, one end of each of the resonance electrodes 2 and 4 reaches the lower surface of the substrate 1 and is connected to the ground electrode 9b.
And the other ends are concave portions 21 and 2 on the upper surface of the substrate 1.
1 are exposed in the back. Therefore, this recess 21,
The length of the resonance electrodes 2 and 4 can be appropriately reduced by further removing the substrate 21. Similarly,
One end of the resonance electrode 3 reaches the upper surface of the substrate 1 and is connected to the ground electrode 9a.
It is exposed in the back. Therefore, the length of the resonance electrode 3 can be appropriately reduced by further removing the substrate in the portion of the concave portion 31. Further, since the open ends of these resonance electrodes are located in the depths of the recesses recessed from the outer surface of the substrate 1, the shielding properties are improved, and the effects of other components mounted close to the characteristics are less likely to be affected. . Next, a method of manufacturing the dielectric filter having the above-described configuration, which is one embodiment of the manufacturing method according to the present invention, will be described. In other words, a large number of dielectric filters are obtained in the manner shown in FIG. 4, thereby greatly improving mass productivity. The area indicated by E is a “cut margin” that is not used in the final product, and the other rectangular area surrounded by the dashed line is the dielectric filter forming area. First, FIG.
As described above, a large number of laminated substrates are manufactured by using a large-area dielectric sheet formed by laminating a predetermined number of green sheets. The resonance electrodes 2 are provided at predetermined positions between the sheets.
Strip-shaped electrode patterns 3 and 4 are formed in parallel. Each electrode pattern has the same width over the entire length. In other words, a plurality of dielectric sheets are formed by forming an electrode pattern corresponding to the above-mentioned resonance electrode and by forming nothing, and furthermore, a conductor film is formed on the entire surface for forming the back surface ground electrode 5 and the front surface ground electrode 6. Some green sheets are formed, and a laminated substrate is formed by laminating them. A large round hole (through hole) A serving as the concave portions 21 and 31 is formed through by machining such as drilling or punching, and a small round hole (through hole) B serving as the concave portions 51 and 52 is formed through. . As is clear from the figure, each of the round holes A and B straddles a cutting position (cutting line C and D) indicated by a dashed line, and the round hole A is aligned with the strip-shaped electrode pattern. , To divide the pattern. In this way, since the through holes are formed in the round holes A and B, each pattern of the resonance electrodes 2, 3, and 4 formed in a large-area dielectric sheet may be formed as one long strip-shaped pattern. Since it is not necessary to form a complicated pattern that is cut or bent at a predetermined position, it can be easily manufactured. In the case of a three-stage filter as in this example, the length of the center resonance electrode 3 is generally shorter than the left and right resonance electrodes 2 and 4. Therefore, it is necessary to increase the amount of cutting of the concave portion 51 facing the central resonance electrode 3. However, in this example, from the cutting lines C and D at the center position of the round hole A having the same diameter for ease of manufacture. This is done by shifting the distance of Then, this large-area substrate is divided into a vertical line C and a horizontal line D.
Then, a filter element having the form shown in FIG. 5 is obtained. These are aligned using an appropriate jig, and a metal film is formed by solid printing on a hatched portion in FIG. As a result, a side-surface ground electrode is formed in a portion other than the concave portion. In this way, forming the side surface ground electrode on the side surface of the laminated substrate other than the concave portion is almost as simple as forming the electrode film on the entire side surface. Therefore, the step of forming the side electrode is greatly simplified, and the overall mass productivity is improved. In this example, the resonance electrodes 2, 3, and 4 are formed to have a predetermined length by changing the cutting amount by shifting the formation positions of the round holes A, but the present invention is not limited to this. The concave portions 21 and 31 may be formed by round holes having a diameter. Further, by changing the shape and / or formation position of the through hole or changing the pattern of the conductor film, it is possible to manufacture a dielectric filter having various structures. That is, the shape of the concave portion formed by removing the side surface of the laminated substrate is an arc shape that forms a part of a round hole in the previous embodiment, but a square shape as shown in FIG. It can take various other forms. The layout of the input / output electrodes is not limited to the electric field coupling type as in the above embodiment, but may be a branch coupling type as shown in FIG. 7 or a magnetic field coupling type as shown in FIG. In each of the embodiments shown in the drawings, the coupling method of the input / output electrode 7 is different, and the main parts are the same as those in the above-described embodiments. . Furthermore, although not specifically shown, in each of the above-described embodiments, three stages were used, but two stages or four stages were used.
A comb line type (open ends of resonators are arranged on the same side) instead of an interdigital type (open ends of resonators are alternately arranged) used in the present invention may be used.
Of course, that is fine.

As described above in detail, according to the present invention, the side ground electrode and one end of the internal resonance electrode are separated by the concave portion formed by removing the side surface of the laminated substrate. One end is an open end. The open end is exposed at the boundary between the two dielectric sheets in the concave portion. By removing the exposed portion, the length of the resonance electrode can be reduced. However, since the exposed open end is recessed in the recess, the shielding property is far superior to that when the exposed end is exposed on the outer surface. Also, forming the side-surface ground electrode on portions other than the concave portions on both side surfaces of the laminated substrate is almost as simple as forming the electrode film on the entire side surface,
Therefore, mass productivity is improved.

[Brief description of the drawings]

FIG. 1 is a plan view (A) and a side view (B) of a dielectric filter manufactured by carrying out the present invention.

FIG. 2 is a perspective view of the dielectric filter shown in FIG.

FIG. 3 is a sectional view taken along line AA in FIG.

FIG. 4 is a view for explaining one embodiment of a method for manufacturing a dielectric filter according to the present invention.

FIG. 5 is a diagram for explaining one embodiment of a method for manufacturing a dielectric filter according to the present invention.

FIG. 6 is a plan view showing another example of the dielectric filter manufactured according to the present invention.

FIG. 7 is a plan view (A) and a side view (B) showing another example of a dielectric filter manufactured according to the present invention.

FIG. 8 is a plan view (A) and a side view (B) showing another example of the dielectric filter manufactured according to the present invention.

FIG. 9 is a configuration diagram of a conventional dielectric filter.

FIG. 10 is a configuration diagram of another conventional dielectric filter.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 laminated substrate 2, 3, 4 resonant electrode 5 back ground electrode 6 front ground electrode 7 a, 7 b, 7 c input / output electrode 9 a upper ground electrode 9 b lower ground electrode 9 c left and right ground electrodes 21, 31, 51, 52 recess A , B Round hole (through hole) C, D Cutting line E Cutting margin

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location H01P 7/08 H01P 7/08

Claims (3)

(57) [Claims] A plurality of dielectric sheets larger than the shape of a laminated dielectric filter to be manufactured are used, and a ground electrode, a ground electrode, and the like are provided on some of the plurality of dielectric sheets.
A conductive film forming at least one of the resonance electrode and the input / output electrode is formed, and a dielectric sheet on which the conductive film is formed and a dielectric sheet on which no conductive film is formed are laminated in a predetermined order. The filter substrate is separated into individual filter elements by cutting a predetermined position of the multilayer substrate, and then a conductive film is formed on the side surface of the filter element, and the side surface is formed on the side surface. A method of manufacturing a dielectric filter in which an earth electrode and an input / output electrode are formed, wherein a predetermined width of a predetermined width that is not used for a final product is provided between a plurality of dielectric filters formed on the large dielectric sheet. A plurality of strip-shaped electrode patterns having the same width are formed in parallel on the surface of the predetermined large dielectric sheet so as to cross a plurality of dielectric filter forming regions, and a cut margin is provided. A through hole is formed at a predetermined position including a cutting position with respect to the laminated substrate in an intersecting direction by machining to divide the continuous strip-shaped electrode pattern into a resonance electrode, and then cut the dielectric sheet at the cutting position. By doing so, a concave portion based on the through hole is formed on the side surface of the separated filter element, and a resonance electrode having a predetermined length is provided. A method for manufacturing a dielectric filter, wherein the side surface ground electrode is formed by performing a printing process of a conductor on a portion located on a surface. 2. forming at least two through-holes on one side of one dielectric filter forming region at a predetermined position including a cutting position on the laminated substrate parallel to the strip-shaped electrode pattern; By cutting the dielectric sheet at a cutting position, a concave portion based on the through hole is formed on a side surface of the separated filter body where the resonance electrode is not exposed, and then, a side surface of the filter body On the other hand, by performing a printing process of a conductor on a portion located on the same surface excluding the concave portion, the side surface ground electrode and the input / output electrode are formed in a separated state via the concave portion. The method for manufacturing a dielectric filter according to claim 1, wherein: 3. The length of each of the band-shaped resonance electrodes is set to a predetermined value according to the amount of substrate removal when forming each of the recesses located at one end of the band-shaped resonance electrode. 3. The method for manufacturing a dielectric filter according to item 1.