JPH1056307A - Manufacture of dielectric resonator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a dielectric resonator with less fluctuation in a resonance frequency by deciding the width of a blade tip surface to permit a blade to be protruded above grooves. SOLUTION: A dielectric body 21 having a conductive film is held by a holding device so as to be rotated with the shaft of the dielectric body 21 as a center, the blade as a removal tool is positioned at the recessed part 28 of the dielectric body 21 and the conductive film is ground by the blade. That is, the blade is moved in a longitudinal direction so as to grind the conductive film on a projected part 28 and a part of the projected part. The blade is provided with the tip surface (grinding surface) having width wider than that of the protected part 28. Therefore, the blade is positioned so as to permit the center of the blade to coincide with the center of the protected part 28, that is, the intermediate position of the first and the second grooves 26 and 27 so that the tip surface of the blade is protruded above the grooves 26 and 27. The width of the tip surface of the blade is decided so as to permit the protruding quantity of the blade to be smaller than the width of the grooves 26 and 27.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric filter, VC
The present invention relates to a method for manufacturing a TEM mode coaxial dielectric resonator for use in O or the like.

[0002]

2. Description of the Related Art A conventional method for manufacturing a dielectric resonator will be described with reference to FIGS. First, a cylindrical dielectric 1 shown in FIG. 1 is prepared. The dielectric 1 has one end face 2, the other end face 3, and the outer peripheral face 4, and further has a through hole 5 extending from the one end face 2 to the other end face 3. Next, the conductive film 6 is formed by applying a silver paste (conductive paste) to the entire exposed surface of the dielectric 1 and baking it. Next, as shown in FIG. 2, the dielectric 1 having the conductor film 6 is held by the chucking device 7 and the dielectric 1 is rotated about the axis as shown by the arrow 8, and the grinding blade ( As shown in FIG. 3, the conductive film 6 on the outer peripheral surface 4 of the dielectric 1 is annularly removed by a blade 9. As a result, the isolation region 10 is formed on the outer peripheral surface, and the quarter-wavelength dielectric resonator is completed. This dielectric resonator has an inner conductor 11 on the wall surface of the through hole 5, an outer conductor 12 on the outer peripheral surface 4, a short-circuit conductor 13 on the other end surface 3, and a terminal conductor 14 on the one end surface 2 and the outer peripheral surface in the vicinity thereof. The short-circuit conductor 13 connects the inner conductor 11 and the outer conductor 12, and the terminal conductor 14 connects the inner conductor 11 to an external circuit.

[0003]

The resonance frequency f0 of the dielectric resonator changes in inverse proportion to the axial length L of the outer conductor 12. For example, when the length L is reduced by 50 μm, the resonance frequency increases by about 5 MHz. Length L of outer conductor 12
Is determined depending on the distance between the chucking device 7 and the tip surface of the blade 9 in FIG. Blade 9 is arrow 15
Is attached to an attachment mechanism (not shown) so as to be movable in the vertical direction and at a predetermined distance from the chucking device 7 as shown by. At this time, an error occurs in the mounting position. Of these errors, an error of a horizontal component indicated by an arrow 16 in FIG. 2 is an error of the length L of the outer conductor 12. At the current level, the error of the length L occurs in the range of +50 to -50 .mu.m, and the variation of the resonance frequency f0 is in the range of +5 to -5 Hz. Therefore, when the deviation of the resonance frequency f0 is required to be smaller than ± 5 MHz, a large number of dielectric resonators are formed and those having a resonance frequency f0 within an allowable range are selected or the frequency is adjusted. It was necessary, and inevitably increased the cost.

Accordingly, an object of the present invention is to provide a method of manufacturing a dielectric resonator having a small variation in resonance frequency.

[0005]

According to a first aspect of the present invention, there is provided an apparatus having one end face, another end face, and an outer peripheral face, and having a through hole extending from the one end face to the other end face. ,
A step of preparing a dielectric having at least one groove on an outer peripheral surface near the one end surface, wherein the groove is formed in an annular shape so as to surround the through hole; and at least an inner conductor of the dielectric resonator; Forming a conductor film so as to cover at least the wall surface of the through hole and the outer peripheral surface having the groove in order to obtain an outer conductor and a terminal conductor; and In order to annularly delete a portion adjacent to the groove, a tool having a tip surface wider than the width of the portion to be removed is prepared, and the tool is so formed that a part of the tip surface of the tool protrudes above the groove. Positioning the tip end face of the tool closer to the one end face side than the groove, removing the conductor film by the tip end face of the tool, and providing an outer conductor and a terminal conductor on the outer peripheral surface of the dielectric. Related to the manufacturing method of dielectric resonators A. The invention according to claim 2 has one end face, the other end face, and an outer peripheral face, has a through hole extending from the one end face to the other end face, and has a first and a second outer peripheral face near the one end face. Two grooves, each of the first and second grooves is formed in an annular shape so as to surround the through hole,
A step of preparing a dielectric in which the first and second grooves are juxtaposed at a predetermined interval; and forming the dielectric to obtain at least an inner conductor, an outer conductor, and a terminal conductor of the dielectric resonator. At least a wall surface of the through hole of the body and the first and second walls;
Forming a conductive film so as to cover the outer peripheral surface having the groove, and forming the first and second conductive films on the outer peripheral surface of the conductive film.
A tool having a tip surface wider than the width of the portion between the first and second grooves is prepared in order to annularly remove the portion between the grooves, and one end of the tip surface of the tool is the first end. And the other end of the tip surface of the tool is the second end.
The tool so that it protrudes above the groove of the first and second
And removing the conductor film with the tip end surface of the tool, and providing an outer conductor and a terminal conductor on the outer peripheral surface of the dielectric. It concerns the method. Further, as described in claim 3, it is also possible to provide only a convex portion without providing a groove. Further, a small-diameter portion can be provided instead of the groove as described in claim 4.

[0006]

According to the invention of each claim, even if the position of the tool for removing the conductive film fluctuates in the axial direction of the dielectric resonator, the position of the tool or the small diameter portion on the tip surface of the tool is changed. As long as the amount of protrusion of the outer conductor or the amount of protrusion from the convex portion is equal to or less than that, no change occurs in the length of the outer conductor. Therefore, the accuracy of the length of the outer conductor and the accuracy of the resonance frequency are improved. According to the second and third aspects of the present invention, not only the variation in the resonance frequency is reduced, but also the width of the deleted portion can be kept constant.

[0007]

Next, a method of manufacturing a dielectric resonator according to an embodiment of the present invention will be described with reference to FIGS. First, a cylindrical dielectric 21 shown in FIG. 4 is prepared. The dielectric 21 has one end face 22, the other end face 23, and an outer peripheral face 24, and has a through hole 25 extending from one end face 22 to the other end face 23. First and second grooves 26 and 27 are provided in a region near one end surface 22 of the outer peripheral surface 24, and a convex portion 28 is formed between the two grooves 26 and 27. The first and second grooves 26 and 27 and the convex portion 28 are formed in an annular shape so as to surround the through hole 25 as a center, that is, make one turn around the outer peripheral surface 24. The dielectric 21 having the grooves 26 and 27 is obtained by forming a molded body by an injection molding method and firing the molded body. Since the injection molding method is a method of forming a predetermined shape using a mold, the dimensional accuracy is set to 0.1.
It can be about 3%. Therefore, the protrusion 28 of FIG.
If the length L from the right end to the other end face 23 of the dielectric 21 is about 8 mm in order to obtain about 1 GHz, this length L
± 24μm if the variation during firing is ignored
It is.

Next, a silver paste (conductive paste) is applied to the entire exposed surface of the dielectric 21 and baked to form a conductor film 29 on the entire surface of the dielectric 21 as shown in FIG. Note that even when the conductor film 29 is formed, the conductor film 29 is formed to have a uniform thickness so that grooves corresponding to the grooves 26 and 27 of the dielectric 21 are formed.

Next, as shown in FIG. 6, the dielectric 21 having the conductor film 29 is held by a chucking device (holding device) 30 and rotated about the axis of the dielectric 21 as shown by an arrow 31, A blade 32 as a removal tool is positioned on the convex portion 28 of the dielectric 21, and the conductive film 29 is ground with the blade 32. That is, as shown by an arrow 33 in FIG. 6, the blade 32 is moved in the vertical direction to grind the conductive film 29 on the projection 28 and a part of the projection 28. The blade 32 has a convex portion 28
Has a tip surface (grinding surface) having a width wider than the width. Therefore, when the blade 32 is positioned so that the center of the blade 32 coincides with the center of the convex portion 28, that is, the intermediate position between the first and second grooves 26 and 27, a part of the tip end surface of the blade 32 becomes And protrudes above the second grooves 26 and 27. The width of the tip surface of the blade 32 is determined so that the amount of protrusion of the blade 32 is smaller than the width of the grooves 26 and 27, and the blade 32 in the horizontal direction indicated by an arrow 34 in FIG.
Even if there is a variation in the position of the conductive film 29,
The width of the blade 32 and the widths of the grooves 26 and 27 are determined so as not to delete portions on the left and right sides of the convex portion 28 of FIG. The target protrusion amount of the blade 32 above the grooves 26 and 27 is desirably the maximum deviation of the mounting position of the blade 32 in the horizontal direction. That is, this maximum deviation is about 50
μm, the target protrusion amount of the blade 32 is about 50 μ
m. It is desirable that the horizontal width of the first and second grooves 26 and 27 be at least about twice the maximum deviation of the mounting position of the blade 32 in the horizontal direction. That is, when the maximum deviation is about 50 μm, the width of the grooves 26 and 27 is set to 100 μm or more. The maximum depth of the grooves 26 and 27 changes depending on the grinding depth of the blade 32,
2 (about 10 μm) from the maximum deviation of about 2 (about 50 μm).
0 μm). Blade 3
It is desirable that the width of the front end face of No. 2 is at least wider than the maximum deviation (about 50 μm) than the target grinding width,
It is also desirable that the maximum deviation is suppressed to about twice (100 μm) or less. The blade 32 is connected to the conductor film 29 on the projection 28.
When the dielectric 21 is rotated in contact with the above, the conductive film 29 on the convex portion 28 is deleted, and a part of the dielectric 21 is further deleted, so that a separation region 35 composed of an exposed surface of the dielectric 21 is obtained. Thereby, based on the conductor film 29, the inner conductor 36 on the wall surface of the through hole 25, the outer conductor 37 on the outer peripheral surface 24 of the dielectric 21, the short-circuit conductor 38 on the other end surface 23, and the one end surface 22 and the outer peripheral surface 24 are formed. A terminal conductor 39 provided partially is obtained, and 1 /
A four-wavelength coaxial dielectric resonator is completed. The completed dielectric resonator is arranged, for example, on a circuit board, the outer conductor 37 is connected to the ground conductor layer of the circuit board according to the surface mounting method, and the terminal conductor 39 is connected to the connection conductor layer of the circuit board.

As is apparent from the above description, in this embodiment, the width of the tip surface of the blade 32 is determined so as to protrude above the grooves 26 and 27. The position at which the conductor film 29 is deleted does not change. Therefore, variation in the axial length L of the outer conductor 37 is reduced, and variation in the resonance frequency f0 is also reduced. Now, the target length L of the outer conductor 37 is 8 mm and is 1 GHz.
In the case of manufacturing the dielectric resonator of the above, if the maximum dimensional variation is about 24 μm at the time of injection molding, the deviation of the resonance frequency is 2.4 MHz, which is smaller than the conventional 5 MHz.

[0011]

[Modifications] The present invention is not limited to the above-described embodiment, and for example, the following modifications are possible. (1) First and second grooves 26 and 27 as shown in FIG.
Can be formed in a V-shape. (2) First and second grooves 26 and 27 as shown in FIG.
Can be formed in a concave shape. (3) Instead of the grooves 26 and 27, the diameter of all the right and left sides of the projection 28 can be made smaller than the diameter of the projection 28 as shown in FIG. Also in this case, the protrusions 28 of the conductive film 24 are removed by a blade wider than the protrusions, so that the protrusions 28 have separation regions. When the dielectric resonator shown in FIG. 10 is surface-mounted on a circuit board, it is desirable to provide a recess or hole in the circuit board for inserting the projection 28. (4) As shown in FIG.
Groove 26 only. In this case, the groove 26
The blade 32 is disposed closer to one end face 22 than the other end, a part of the blade 32 is protruded above the groove 26, and the conductive film 29 on the left side of the groove 26 is ground. In this case, the width of the region separating the outer conductor and the terminal conductor changes according to the displacement of the blade 32, but the effect of reducing the variation in the length L of the outer conductor 37 can be obtained as in the embodiment. (5) As shown in FIG.
And a small diameter portion 21b, a large diameter portion 21a and a small diameter portion 21b.
Can be defined as the boundary between the outer conductor and the terminal conductor. In this case, a part of the blade 32 protrudes above the small-diameter portion 21b and the conductor film 29 on the surface 24a of the large-diameter portion 21a.
Is ground to form a separation region in the same manner as in the embodiment. According to the embodiment shown in FIG. 12, the same effects as those of the embodiment and the modification of FIG. 11 can be obtained. (6) A conductive paste is applied to an injection-molded dielectric molded product, and baking of the conductive paste and firing of the dielectric can be performed simultaneously. (7) The short-circuit conductor 38 can be omitted to provide a 1/2 wavelength dielectric resonator. (8) The terminal conductor 39 on the outer peripheral surface 24 can be capacitively coupled to the inner conductor 36 by omitting the conductor film on the one end surface 22. (9) The conductor film 29 can be formed by plating.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a conventional dielectric having a conductive film.

FIG. 2 is a cross-sectional view showing formation of a separation region by a conventional blade.

FIG. 3 is a perspective view of a conventional dielectric resonator.

FIG. 4 is a sectional view showing a dielectric according to an example of the present invention.

FIG. 5 is a cross-sectional view showing a structure in which a conductor film is formed on the dielectric of FIG. 4;

FIG. 6 is a cross-sectional view showing a state in which the conductive film of FIG. 5 is selectively shaved with a blade.

FIG. 7 is a front view showing a dielectric resonator manufactured according to an example.

FIG. 8 is a sectional view showing a modification of the groove.

FIG. 9 is a sectional view showing another modification of the groove.

FIG. 10 is a cross-sectional view showing a modified example in which all the parts except for the protrusions are reduced in diameter instead of the grooves.

FIG. 11 is a sectional view showing a modification in which only one groove is provided.

FIG. 12 is a cross-sectional view showing a modification in which a small-diameter portion is provided instead of a groove.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 21 Dielectric 26, 27 Groove 29 Conductor film 32 Blade

Claims (4)

[Claims] 1. An end face, an end face, and an outer peripheral face, a through hole extending from the one end face to the other end face, and at least one groove on an outer peripheral face near the one end face, Providing a dielectric in which the groove is formed in an annular shape so as to surround the through hole; and providing at least the through hole of the dielectric to obtain at least an inner conductor, an outer conductor, and a terminal conductor of the dielectric resonator. Forming a conductor film so as to cover the wall surface of the hole and the outer peripheral surface having the groove; and removing the portion of the outer peripheral surface of the conductor film adjacent to the groove in an annular manner. Prepare a tool having a tip end face wider than the width of the portion, position the tip end face of the tool to the one end face side than the groove so that a part of the tip end face protrudes above the groove, The conductive film is removed by the tip surface of the tool, and the dielectric film is removed. Method for manufacturing a dielectric resonator characterized by comprising a step of providing an outer conductor and the terminal conductor on the outer peripheral surface of the. 2. An end face, an end face, and an outer peripheral face, a through hole extending from the one end face to the other end face, and first and second grooves formed on an outer peripheral face near the one end face. Each of the first and second grooves is formed in an annular shape so as to surround the through hole, and the first and second grooves are formed of a dielectric material juxtaposed at a predetermined interval. Providing a step of preparing at least an inner conductor, an outer conductor, and a terminal conductor of the dielectric resonator by at least a wall surface of the through hole of the dielectric and the outer peripheral surface having the first and second grooves. Forming a conductive film so as to cover; and a portion between the first and second grooves to annularly delete a portion between the first and second grooves on the outer peripheral surface of the conductive film. A tool having a tip end surface wider than the width of the tool is prepared, and one end of the tip end surface of the tool fits over the first groove. The tool is positioned at a portion between the first and second grooves so that the other end of the tip surface of the tool protrudes above the second groove. Removing the film and providing an outer conductor and a terminal conductor on the outer peripheral surface of the dielectric. 3. An end surface having one end surface, the other end surface, and an outer peripheral surface, a through hole extending from the one end surface to the other end surface, a convex portion on an outer peripheral surface near the one end surface, and Providing a dielectric whose portion is formed in an annular shape so as to surround the through hole; and at least the through hole of the dielectric to obtain at least an inner conductor, an outer conductor, and a terminal conductor of the dielectric resonator. Forming a conductor film so as to cover the wall surface and the outer peripheral surface having the convex portion; and forming the convex portion on the outer peripheral surface of the conductor film so as to annularly delete the portion above the convex portion. Prepare a tool having a tip surface wider than the width, position the tip surface of the tool on the protrusion so that a part of the tip surface of the tool protrudes above the protrusion, the tip of the tool The conductor film is removed by a surface, and an outer conductor and a terminal conductor are provided on the outer peripheral surface of the dielectric. Method for manufacturing a dielectric resonator characterized by comprising a that step. 4. An end surface having one end surface, the other end surface, and an outer peripheral surface, a through hole extending from the one end surface to the other end surface, and a portion adjacent to the one end surface is a large diameter portion. A step of preparing a dielectric having a small-diameter portion between the large-diameter portion and the other end surface; and obtaining at least the inner conductor, the outer conductor, and the terminal conductor of the dielectric resonator. Forming a conductive film so as to cover the wall surface of the through hole and the outer peripheral surface; and removing a portion of the conductive film on the large-diameter portion in a ring shape, the tip being wider than the width of the portion to be deleted. Prepare a tool having a surface, position the tool so that a part of the tip surface of the tool protrudes from the large diameter portion onto the small diameter portion,
Removing the conductor film with the tip end surface of the tool and providing an outer conductor and a terminal conductor on the outer peripheral surface of the dielectric.