JPH0945583A - Back adjustment trimmer capacitor - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To provide a rear surface adjustment type trimmer capacitor which has extremely strong bonding strength with a printed wiring board, has no restriction in mounting the printed wiring board on an electronic device, and has excellent impact resistance. . A dielectric rotor (2) and adjusting pins (3) are superposed on a stator substrate (1) having a stator electrode (12), and a stator terminal (1) is provided on a pair of opposing end faces of the stator substrate (1).
A trimmer capacitor 10 having a rotor terminal 41 and a stator terminal 13 and a rotor terminal 4
Reference numeral 1 denotes an extension portion 13 extending to the upper surface side of the stator substrate 1.
It is a rear surface adjustment type trimmer capacitor including a and 14a and terminal portions 13b and 14b which are widened on the upper surface side of the stator substrate 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backside adjustment trimmer capacitor.

[0002]

2. Description of the Related Art Generally, an open type trimmer capacitor has a dielectric rotor having rotor electrodes therein rotatably superposed on a stator substrate having stator electrodes by adjusting pins, and a pair of opposing stator substrates. On the end face thereof, a stator terminal connected to the stator electrode and a rotor terminal connected to the rotor electrode are arranged.

Specifically, the stator substrate is made of an insulating resin, and a through hole is formed in the center of the surface of the stator substrate. A horseshoe-shaped stator electrode is formed around the through hole. A stator terminal connected to the stator electrode was formed on one of the pair of opposed end faces.

Further, the dielectric rotor is made of a dielectric ceramic or the like, and has a through hole formed in the center thereof, and a rotor electrode having a semicircular shape, for example, is formed around the internal through hole. A part of the rotor electrode is led out to the inner wall of the through hole.

The adjusting pin is composed of a head portion having an adjusting groove into which a driver (adjusting member) or the like is inserted, and a pin portion extending below the head portion. The tip of the pin portion is caulked on the bottom surface side of the stator substrate.

The rotor terminal is connected to the rotor electrode and is arranged on the other end surface of the stator substrate. This is formed integrally with a rotor fitting arranged on the bottom surface of the stator substrate. That is, the rotor fitting is composed of a rotor terminal portion, a crimp receiving portion for crimping the pin portion of the adjustment pin, and a connecting portion for connecting the rotor terminal portion and the receiving portion. A through hole is formed in the receiving portion.

Then, rotor fittings are arranged on the bottom surface of the stator substrate, and the dielectric rotor is arranged on the stator substrate. The adjusting pins are arranged on the dielectric rotor. The tip of the pin portion is caulked by being inserted into the through hole of the substrate and the through hole of the receiving portion. In addition, between the dielectric rotor and the head part of the adjustment pin,
Further, a conductive adhesive is interposed between the pin portion and the lead-out portion of the rotor electrode. As a result, the dielectric rotor and the adjusting pin cooperate with each other, and the rotor electrode and the rotor fitting (rotor terminal) are electrically connected via the pin portion.

In such a trimmer capacitor, the facing area between the rotor electrode and the stator electrode is changed by inserting a driver or the like into the adjusting groove of the head portion of the adjusting pin and rotating the same by a predetermined amount. The capacity corresponding to the area is derived from between the stator terminal and the rotor terminal.

Conventionally, such a trimmer capacitor is arranged on a predetermined wiring of a printed wiring board, and the capacitance is adjusted from the upper surface side of the printed wiring board by using an adjusting member such as a driver.

In such a mounting structure, the predetermined wiring, the stator terminal of the trimmer capacitor and the rotor terminal are joined by soldering or the like, and the printed wiring is arranged so that the bottom surface of the stator substrate of the trimmer capacitor faces the surface of the printed wiring board. Since it will be placed on the substrate,
Even if a predetermined force is applied from the front side to the back side of the printed wiring board from the adjustment member such as a driver to the trimmer capacitor in order to rotate the adjustment pin by a predetermined amount, there is no change in the solder joint state. No, stable joining could be maintained.

Further, as one of the forms for mounting the trimmer capacitor on the printed wiring board, there is a mounting structure that enables adjustment from the back side of the printed wiring board. This forms a through hole into which a trimming capacitor of the printed wiring board is mounted, through which an adjusting member can be inserted, or a structural portion on the stator substrate of the trimmer capacitor, for example, a dielectric rotor or an adjusting pin can be arranged. The trimmer capacitor is arranged such that the upper surface side of the stator substrate faces the surface of the printed wiring board. In this case, the stator terminal and the rotor terminal arranged on the end surface of the stator substrate need to extend to the surface of the stator substrate. A trimmer capacitor having a structure in which the back side of the printed wiring board can be adjusted, for example, a structure in which terminal electrodes are arranged on the upper surface of the stator board is particularly referred to as a "back surface adjustment type trimmer capacitor".

[0012]

However, when the back surface adjustment type trimmer capacitor is mounted as described above, there are various inconveniences.

First, when an adjusting member such as a driver is inserted into the adjusting groove of the adjusting pin of the trimmer capacitor from the rear surface side of the printed wiring board through the adjusting through hole,
The direction of the force at the time of insertion is from the back side to the front side of the printed wiring board, and it acts in the direction of peeling the bond between the trimmer capacitor and the printed wiring board. It may have had an adverse effect. This is also because the trimmer capacitor that the stator substrate and the printed wiring board face each other is substantially only the terminal portion.

Further, depending on the type of the printed wiring board, the structure of the mounted trimmer capacitor on the stator substrate, such as the dielectric rotor or the head portion of the adjustment pin, projects from the back surface side of the printed wiring board. There was something that happened If a part of the trimmer capacitor protrudes from the back surface side of the printed wiring board in this manner, electronic devices and the like incorporating the printed wiring board are also subject to restrictions such as design.

Further, when a shock is applied from the printed wiring board, especially from the back surface side, the joint state between the trimmer capacitor and the printed wiring board may be adversely affected.

The present invention has been devised in view of the above-mentioned problems, and an object thereof is to provide a rear surface adjustment type trimmer capacitor having extremely strong bonding strength.

Another object is to provide a rear surface adjustment type trimmer capacitor in which a part of the trimmer capacitor does not project to the rear surface side of the printed wiring board.

[0018]

SUMMARY OF THE INVENTION According to the present invention, a dielectric rotor having a rotor electrode therein is rotatably superposed on a stator substrate having a stator electrode by an adjusting pin, and a pair of opposing stator substrates are provided. Is a trimmer capacitor in which a stator terminal connected to the stator electrode and a rotor terminal connected to the rotor electrode are respectively arranged on the end faces of the.

The stator terminal and the rotor terminal are composed of an extending portion extending to the upper surface side of the stator substrate and a terminal portion widened on the upper surface side of the stator substrate.

With respect to the lengths of the extension portions of the stator terminal and the rotor terminal, a part of the trimmer capacitor protruding beyond the height of the terminal portion is concealed by the printed wiring board on which the rear surface adjustment type trimmer capacitor is mounted. Is set to.

[0021]

According to the present invention, the stator terminal and the rotor terminal, which are joined to the printed wiring board so that the back surface can be adjusted, are composed of the extending portion and the wide terminal portion, and the terminal portion of the stator substrate is formed by the extending portion. It is located on the top surface. Then, with the wide terminal portions, the upper surface side (adjustment pin side) of the trimmer capacitor is soldered to a predetermined wiring in a direction facing the printed wiring board.

Therefore, the strength of the solder joint is remarkably improved by the increase of the joint area portion, and even if the adjusting member is inserted from the back surface side of the printed wiring board, the force at the time of insertion is the same as the printed wiring board. Even if it acts in the direction of peeling the trimmer capacitor, the strong bonding state does not change.

The length of the extended portion is set in consideration of the thickness of the printed wiring board. Specifically, it is desirable to set such that a part of the trimmer capacitor does not project to the back surface side of the printed wiring board. If you do this,
Even when mounted on a printed wiring board, a part of the trimmer capacitor does not protrude from the back surface side of the printed wiring board, so that the printed wiring board itself is easy to handle and no other various restrictions occur. Further, even if an impact is applied from the back surface side of the printed wiring board, the impact is not directly applied to the trimmer capacitor, so that the strong joining state does not change.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a back surface adjustment type trimmer capacitor of the present invention will be described in detail with reference to the drawings. FIG. 1 is a plan view of a trimmer capacitor of the present invention, and FIG. 2 is a vertical sectional view.

The rear surface adjustment type trimmer capacitor 10 is mainly composed of a stator substrate 1, a dielectric rotor 2, an adjustment pin 3, and a rotor fitting 4.

The stator substrate 1 is a substantially rectangular parallelepiped made of resin, and a through hole 11 through which the pin portion 32 of the adjustment pin 3 is inserted is formed in a substantially central portion of the stator substrate 1. In addition, a stator metal piece including a stator electrode 12 and a stator terminal 13 is embedded in the stator substrate 1. The stator terminal 13, which is one end of the stator metal fitting, extends from the vicinity of the bottom surface of the one end surface of the stator substrate 1, and the stator electrode 12, which is the other end of the stator metal fitting, has a substantially horseshoe shape and is formed on the surface of the stator substrate 1. Is exposed to.

The stator substrate 1 having such a complicated shape and in which the stator fittings are embedded is formed by resin molding.

The dielectric rotor 2 is in the form of a disc made of a predetermined dielectric material, and the pin portion 32 of the adjusting pin 3 is provided in the central portion thereof.
Is formed with a through hole 21. A semicircular rotor electrode 22 is formed inside the dielectric rotor 2. A part of the rotor electrode 22 appears in the through hole 21, and a rotor extraction conductor film 23 connected to the rotor electrode 22 is formed on the inner wall of the through hole 21. In such a dielectric rotor 2, a dielectric green sheet and a dielectric green sheet on which a pattern of a predetermined metal conductor film to be the rotor electrode 22 is printed are laminated, and a hole to be the through hole 21 is formed in the laminated body. It is formed by printing a conductor film that is to be the conductor film 23 to be drawn out of the rotor and baking it.

The adjustment pin 3 is made of a metal member and is composed of a head portion 31 having an adjustment groove 31a formed on its surface, and a pin portion 32 hanging from the head portion 31. The pin portion 32 is inserted into the through hole 21 of the dielectric rotor 2, the through hole 11 of the stator substrate 1, and the through hole of the caulking receiving portion 42 of the rotor fitting described later, and the tip portion thereof is caulked. .

The rotor metal fitting 4 is made of an elastic metal member and has a rotor terminal 41 and a crimp receiving portion 4 at one end thereof.
2 and the connecting portion 43. Rotor terminal 41
Is extended to the end surface of the stator substrate 1 that faces the end surface on which the stator terminals 13 are formed. The receiving portion 42 is
For example, it has a circular shape, and a through hole through which the pin portion 32 of the adjustment pin 3 is inserted is formed in the central portion thereof.

The trimmer capacitor 10 having such a structure has the dielectric rotor 2 on the surface of the stator substrate 1.
The rotor fittings 4 are respectively arranged on the back surface, and subsequently, the pin portions 32 of the adjustment pins 3 are used as the through holes 21 of the dielectric rotor 2, the through holes 11 of the stator substrate 1, and the receiving portions 42 of the rotor fitting 4, respectively. The tip portion of the pin portion 32 which is inserted and protruded from the receiving portion 42 is caulked.

The adjusting pin 3 and the dielectric rotor 2 are bonded and fixed to each other via a conductive adhesive material such as solder or conductive resin. As a result, the dielectric rotor 2 and the adjusting pin 3 are interlocked with the rotating operation of the adjusting pin 3 on the stator substrate 1, and the rotor electrode 22 and the adjusting pin 3 are electrically conducted. .

As described above, the trimmer capacitor has a predetermined capacity between the stator terminal 13 and the rotor terminal 41 by inserting a driver (adjustment member) into the adjustment groove 31a of the adjustment pin 3 and rotating by a predetermined amount. can get. That is, as the dielectric rotor 2 rotates, the facing area between the stator electrode 12 and the rotor electrode 22 inside the dielectric rotor 2 changes,
The capacitance corresponding to the facing area and the dielectric constant of the dielectric porcelain existing between them is the stator terminal 13 and the rotor terminal 41.
(The rotor electrode 22, the conductive film 23, the adjusting pin 3, and the rotor fitting 4 are electrically connected to each other).

The characteristic of the present invention is that the stator terminal 1
3, the rotor terminal 41, the extension portion 13a, 1 respectively
4a and terminal portions 13b and 14b.

The extending portion 13a of the stator terminal 13 is bent and extends from the portion led out from the stator substrate 1 to the upper surface side of the stator substrate 1, whereby the terminal portion 13b at the tip thereof is formed on the stator substrate 1. It will be located on the upper side of 1.

The extending portion 14a of the rotor terminal 41 is bent and extends from the bottom surface of the stator substrate 1 to the upper surface side of the stator substrate 1, so that the terminal portion 14b at the tip of the extending portion 14a of the stator substrate 1. It will be located on the upper side.

Further, both terminal portions 13b and 14b are larger than the widths of the extending portions 13a and 14a, respectively,
This increases the solder joint area. For example, it is formed in the width direction of the stator substrate 1 to have a width substantially the same as the width.

Such a rear surface adjustment type trimmer capacitor is arranged on the printed wiring board so that the rear surface can be adjusted, as shown in FIG. In the figure, 5 is a printed wiring board, 51 is an adjusting through hole, and 52a and 52b are predetermined wirings formed around the adjusting through hole on the front surface side of the printed wiring board.

As shown in FIG. 3, predetermined wirings 52a, 52
cream solder is applied to b, a part of the rear surface adjustment type trimmer capacitor 10, for example, the dielectric rotor 2 or the adjustment pin 3 is arranged in the adjustment through hole 51, and the upper surface of the stator substrate 1 is attached to the printed wiring board 5. The terminal portion 13b of the stator terminal 13 so that it faces the surface of the predetermined wiring 52a.
Then, the terminal portion 14b of the rotor terminal 41 is brought into contact with the predetermined wiring 52b.

In this state, heat treatment such as reflow treatment and slow cooling treatment are performed. As a result, the terminal portion 13b of the stator terminal 13 and the predetermined wiring 52a are firmly joined to each other, and the terminal portion 14b of the rotor terminal 41 and the predetermined wiring 52b are firmly joined to each other. Moreover, since the terminal portions 13b and 14b have a wide shape, the bonding strength thereof is extremely strong.

With respect to the rear surface adjustment type trimmer capacitor thus joined to the printed wiring board, a driver (adjustment member) or the like is attached to the adjustment pin 3 from the rear surface side of the printed wiring board through the adjustment through hole 51. The adjustment member is inserted into the adjustment groove 31a, and the adjustment member is rotated by a predetermined amount to perform adjustment in order to obtain a desired capacity.

At this time, the adjusting member exerts a force from the back surface side to the front surface side of the printed wiring board 5 (arrow A), and acts to peel off the trimmer capacitor 10 bonded to the surface of the printed wiring board 5 (arrow a). However, since the printed wiring board 5 and the trimmer capacitor 10 are firmly joined to each other by the predetermined wirings 52a and 52b and the wide terminal portions 13b and 14b, no peeling occurs at the joined portion and the joining strength is high. Does not cause structural defects that lower the

As a result, the trimmer capacitor 10 capable of stable back surface adjustment is achieved.

Also, one of the important things is that a part of the back surface adjustment type trimmer capacitor 10 joined to the printed wiring board 5 in a back surface adjustable manner, for example, the head portion 31 of the adjustment pin 3.
That is, the dielectric rotor 2 does not protrude from the back surface side of the printed wiring board 5. In FIG. 5, the head portion 31 of the adjustment pin 3 is embedded in the adjustment through hole 51 of the printed wiring board 5.

Specifically, the protrusion amount (ΔT) of the dielectric rotor 2 or the head portion 31 of the adjusting pin 3 protruding beyond the terminal portions 13b and 14b located on the upper surface side of the stator substrate 1 is
The positions of the terminal portions 13b and 14 and the thickness of the dielectric rotor 2 and the thickness of the head portion 31 of the adjusting pin 3 are controlled so as to be smaller than the thickness Δt of the printed wiring board 5.

In this way, even if the above-mentioned trimmer capacitor 10 is adjustably soldered to the predetermined wirings 52a and 52b on the front surface side of the printed wiring board 5 from the rear surface side of the printed wiring board 5, the printed wirings are formed. The adjusting pin 3 of the trimmer capacitor does not project from the back surface of the substrate 5. Therefore, for example, even if the printed wiring board 5 is attached to an electronic device or the like, a part of the trimmer capacitor does not protrude from the back surface side of the printed wiring board 5, so that the mounting structure of the printed wiring board 5 is improved. No restrictions are given.

Further, when the printed wiring board 5 is attached, even if an external impact is applied from the back surface side of the printed wiring board 5, the dielectric rotor 2 and the adjustment pin 3 which are a part of the trimmer capacitor are affected by the external impact. Since no impact is applied,
It does not hinder the joint part of the trimmer capacitor.

In the above embodiment, the stator terminal 1
3. The extending portion of the rotor terminal 41 is near the bottom surface side of the stator substrate 1 or from the bottom surface portion of the stator substrate 1, but the extending portion may be anywhere. That is, both the stator metal fittings and the rotor metal fittings may be embedded in the stator substrate 1, or depending on the strength of the embedding, they may extend from the central portion of the thickness of the stator substrate 1 or from the upper surface side. I do not care.

[0049]

INDUSTRIAL APPLICABILITY As described above, the trimmer capacitor of the present invention is a back surface adjustment type trimmer capacitor in which the bonding strength with the printed wiring board is extremely strong.

Further, a part of the trimmer capacitor, that is,
Since the dielectric rotor and adjustment pins do not project to the back side of the printed wiring board, there are no restrictions on mounting the printed wiring board on electronic devices, and there is no obstacle to the impact on the back side of the printed wiring board. Not a back adjustment trimmer capacitor.

[Brief description of drawings]

FIG. 1 is a plan view of a backside adjustment trimmer capacitor of the present invention.

FIG. 2 is a sectional view of a rear surface adjustment type trimmer capacitor of the present invention.

FIG. 3 is a cross-sectional view showing a state where the back surface adjustment type trimmer capacitor of the present invention is mounted on a printed wiring board.

[Explanation of symbols]

 10 --- Trimmer capacitor 1-stator substrate 11-through hole 12-stator electrode 13-stator terminal 13a-extension part of stator terminal 13b-・ ・ Terminal part of stator terminal 2 ・ ・ ・ ・ ・ ・ ・ ・ Dielectric rotor 21 ・ ・ ・ ・ Through hole 22 ・ ・ ・ ・ Rotor electrode 3 ・ ・ ・ Adjustment pin 31 ・ ・ ・ Head part 32 ・ ・・ ・ ・ Pin part 4 ・ ・ ・ Rotor metal fitting 41 ・ ・ ・ Rotor terminal 14a ・ ・ ・ ・ Rotor terminal extension part 14b ・ ・ ・ ・ Rotor terminal terminal part 42 ・ ・ ・ Spring part 5 ··· Printed wiring board 51 ··· Adjusting through holes 52a, 52b ··· Wiring

Claims (1)

[Claims] 1. A dielectric rotor having a rotor electrode therein is rotatably superposed on a stator substrate having a stator electrode by means of an adjusting pin, and the pair of end faces of the stator substrate are connected to the stator electrode. And a rotor terminal connected to the rotor electrode, wherein the stator terminal and the rotor terminal are an extension part extending to the upper surface side of the stator substrate and an upper surface side of the stator substrate. A rear surface adjustment type trimmer capacitor having a wide terminal portion.