JP3586851B2 - Method for manufacturing dielectric ceramic block - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a dielectric filter used for a communication electronic device and the like and a dielectric resonator used for the same, and more particularly, to a method of manufacturing a dielectric ceramic block for the dielectric resonator.
[0002]
[Prior art]
Conventionally, as a dielectric resonator used in a general dielectric filter, there is a λ / 4 coaxial type, in which a through hole is provided in a central axis direction of a dielectric ceramic block, and one end face where the through hole is opened is formed. By covering the entire surface of the dielectric ceramic block including the through hole except for the open end surface with a conductive film, a dielectric resonator having the open end surface as a non-conductive surface can be obtained.
[0003]
In this dielectric coaxial resonator, the open end face is not provided with a conductive film, and the non-conductive surface portion has the maximum electric field in terms of electromagnetic energy, and leakage of electromagnetic waves occurs from this portion. Since the leakage of the electromagnetic wave has an adverse effect on peripheral devices, the leakage of the electromagnetic wave is normally blocked by housing the dielectric resonator in a metal case or by using a non-through hole structure.
[0004]
In the case of the above-described non-through hole structure, the dielectric ceramic block has at least one non-through hole along the central axis in the longitudinal direction, and in order to make the effect of blocking electromagnetic wave leakage more remarkable, The diameter of the non-through hole is formed so as to increase from the opening to the hole closing surface. When manufacturing a dielectric ceramic block having this non-through hole structure, as shown in FIG. 3, the hole diameter decreases from one end to the other end (FIG. 3A), or gradually decreases. In the dielectric ceramic block 11 having at least one through hole 13 formed as shown in FIG. 3B, the opening end face of the ceramic block having the larger hole diameter is closed by a separately prepared dielectric ceramic plate 12. Thus, the non-through holes 13 and 131 were formed as hole closing surfaces.
[0005]
[Problems to be solved by the invention]
The outer surface of the dielectric ceramic block obtained by this structure and the entire surface of the non-through hole wall are covered with a conductive film, and have two input / output electrodes formed in an electrically insulated state. The transmission characteristics of a filter manufactured by using the above resonator have a large variation in characteristics depending on the bonding state because the dielectric ceramic block and the dielectric ceramic plate are bonded by bonding.
[0006]
The present invention has been made to solve such problems, and a technical problem thereof is to provide a method for obtaining a dielectric ceramic block for obtaining a dielectric filter having stable transmission characteristics. is there.
[0007]
[Means for Solving the Problems]
According to the present invention, at least one non-through hole is formed in parallel with the central axis direction, and the diameter of the hole of the non-through hole increases from the opening toward the hole closing surface. As a method of manufacturing the ceramic block, a green dielectric ceramic divided block having a shape divided along the central axis direction of the dielectric ceramic block is manufactured by a molding means such as a press, and a truncated cone opening on the divided surface is formed. A truncated conical block made of solid paraffin or the like is fitted into the recess of the longitudinal shape, and a green dielectric ceramic divided block of the same shape is laminated, and integrally formed by hot pressing or the like, and then removed at 300 to 500 ° C. After performing binder treatment to vaporize solid paraffin in the non-through holes of the dielectric block, sintering is performed at a temperature of 1000 ° C or more. Production method of the dielectric block to obtain.
[0008]
According to the present invention, at least one non-through hole is formed in parallel with the central axis direction, and the diameter of the non-through hole is formed so as to gradually increase from the opening to the hole closing surface. As a method of manufacturing a dielectric ceramic block, a green dielectric ceramic divided block having a shape divided along a central axis direction of the dielectric ceramic block is manufactured by a press or the like, and a multi-step type having an opening on a divided surface is formed. After inserting a multi-stage block made of solid paraffin or the like into a hollow with a non-through hole longitudinal shape, and further stacking green dielectric ceramic divided blocks of the same shape, and forming them integrally by forming means such as hot press After performing binder removal treatment at 300 to 500 ° C. and evaporating solid paraffin in the non-through holes of the dielectric block, at a temperature of 1000 ° C. or more, Production method of the dielectric block, characterized by forming is obtained.
[0009]
According to the present invention, there is provided a method for producing the dielectric ceramic block, wherein solid paraffin is used as the solid organic substance.
[0010]
【Example】
Hereinafter, examples of the present invention will be specifically described.
[0011]
(Example 1)
In this embodiment, as the material of the dielectric block, a barium titanate-based material having a relative dielectric constant ε of 90 to 120 was used. As shown in FIG. 1, one set of a shape divided along the central axis direction in the longitudinal direction is prepared, and each is overlapped on the divided surface to form one non-through hole, and the non-through hole is formed. The green dielectric ceramic divided block 111 is formed by a dry or wet press so that the diameter of the hole becomes larger from the opening to the hole closing surface by a dry or wet press [FIG. 1 (a)]. The block 3 having a truncated cone shape made of solid paraffin is fitted into the concave portion 2 of the divided surface [FIG. 1 (b)], and a green dielectric ceramic divided block 112 having the same shape as the divided block 1 'is overlapped [FIG. 1 (c)]. [FIG. 1 (d)], and the binder is removed from the organic binder and the solid paraffin in the air at a temperature of 300 to 500 ° C. The solid paraffin in the non-through hole 4 of the lamic block 1 is vaporized [FIG. 1 (e)] and sintered at a temperature of 1000 ° C. or more, so that the diameter of the hole increases from the opening to the hole closing surface. Thus, a dielectric ceramic block (sintered body) 5 having a non-through hole 6 formed as described above is obtained. In this embodiment, the case where the number of non-through holes is one is shown, but the same applies to the case where there are a plurality of non-through holes.
[0012]
(Example 2)
In this embodiment, the same material as that of the first embodiment is used. As shown in FIG. 2, one set of the shape divided along the central axis direction in the longitudinal direction is prepared, and one non-through hole is formed by overlapping each of the divided surfaces, and the non-through hole is formed. The green dielectric ceramic divided block 71 is formed by a dry or wet press so that the hole diameter gradually increases as the hole diameter increases from the opening to the hole closing surface [FIG. 2 (a)]. The block 31 having a step made of solid paraffin is fitted into the divided surface concave portion 21 of the body ceramic divided block 71 [FIG. 2B], and a green dielectric ceramic divided block 72 having the same shape as the divided block 71 is overlapped [FIG. 2 (c)], and molded by a hot press or the like to integrate (FIG. 2 (d)). The binder is removed from the organic binder and the solid paraffin at 300 to 500 ° C. in the air. Then, the solid paraffin in the non-through hole 41 of the dielectric ceramic block 7 is vaporized [FIG. 2 (e)] and sintered at a temperature of 1000 ° C. or more, so that the diameter of the hole changes from the opening to the hole closing surface. As a result, a dielectric ceramic block (sintered body) 51 having a non-through hole 61 formed so as to gradually increase in size is obtained. In this embodiment, the case where the hole diameter of the non-through hole has two stages has been described, but the same applies to the case of a multi-stage shape having three or more stages.
[0013]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the dielectric ceramic block which has a non-through-hole with a larger hole diameter of a closing surface than the hole diameter of the opening part of the resonator for dielectric filters used for communication electronic equipment can be obtained by a simple process. .
[Brief description of the drawings]
FIG. 1 is a process chart showing one embodiment of the present invention.
FIG. 2 is a process chart showing another embodiment of the present invention.
FIG. 3 is a diagram showing a configuration of a conventional dielectric ceramic block.
[Explanation of symbols]
1,7 Green dielectric ceramic blocks 111,112,71,72 Green dielectric ceramic divided block 2,21 Concave part 3,31 (made of solid paraffin) Block 4,41 Non-through hole (green)
5,51 Dielectric ceramic block (sintered body)
6,61 Non-through hole 11 Dielectric ceramic block (sintered body)
12. Dielectric ceramic plate (sintered body)
13,131 Through-hole

Claims (3)

When manufacturing a dielectric ceramic block having at least one non-through hole in the axial direction and having a hole diameter of the non-through hole increasing from the opening to the hole closing surface, the dielectric ceramic block A green dielectric ceramic divided block having a shape divided in the axial direction is prepared, and the non-through hole formed on the divided surface is fitted into the concave portion formed of a solid organic material in a concave portion formed by dividing the cone. A trapezoidal block is fitted, a dielectric ceramic divided block having the same shape as the dielectric ceramic divided block is overlapped, pressed and integrated to perform a binder removal treatment at 300 to 500 ° C. After evaporating the solid organic matter contained in the non-through hole of the dielectric ceramic block, and sintering at a temperature of 1000 ° C. or more. Manufacturing method of a dielectric ceramic block. In manufacturing a dielectric ceramic block having at least one non-through hole in the axial direction and having a hole diameter of the non-through hole gradually increased from the opening to the hole closing surface, A green dielectric ceramic divided block having a shape divided in the axial direction of the dielectric ceramic block is prepared, and the non-through hole formed on the divided surface is formed of a solid organic material in a concave portion having a divided shape. A multi-stage block to be fitted is inserted, the dielectric ceramic divided block having the same shape as the dielectric ceramic divided block is overlapped, pressed and integrated, and then subjected to a binder removal treatment at 300 to 500 ° C. After evaporating the solid organic matter contained in the non-through hole of the integrated dielectric ceramic block, sintering is performed at a temperature of 1000 ° C. or more. Manufacturing method of a dielectric ceramic block, wherein. 3. The method for producing a dielectric ceramic block according to claim 1, wherein solid paraffin is used as the solid organic substance.

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