JPS62101010A - Printed coil - Google Patents

Abstract

PURPOSE:To obtain practical frequency characteristics, self resonance frequency fo thereof is not lowered, by fixing a conductor, in which two or more of spiral shapes or zigzag shapes are connected in series, to the surface of a dielectric substrate. CONSTITUTION:A conductor 7 is fastened onto one surface of a ceramic dielectric substrate 6, and connects two spiral shapes in series. One spiral shape forms a first oil section 8, and the other spiral shape forms a second coil section 9. A desired inductance value can be obtained between one terminal section 7a and the other terminal section 7b of the conductor 7 in the printed oil. The printed coil is shaped, dividing the desired inductance value into two spiral shaped conductors connected in series, thus extremely reducing floating capacitance Cp, then preventing the lowering of self-resonance frequency fo, and sufficiently practical frequency characteristics can be acquired.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of the Invention) The present invention relates to a printed coil in which a conductor is fixed to the surface of a dielectric substrate, which has hitherto been considered difficult to put into practical use.

(Prior art) Conventionally, a spiral-shaped (or zigzag-shaped conductor) is fixed to one surface of an insulating substrate or a magnetic substrate.
There is a Britcoil.

FIGS. 4(A) and 4(B) are conventional printed coils having a spiral conductor fixed to one surface of an insulating substrate. However, Fig. 4(A) is a plan view, Fig. 4C
B) is a side sectional view of the portion indicated by the chain line A=-A'.

In this printed coil, C,1 is an insulating substrate made of ceramics, resin, or the like. A spiral conductor 2 is fixed to one surface of the insulating substrate 1 by a method such as printing a conductive paste. This printed coil consists of one end 2a of the conductor 2 and the other end 2a of the conductor 2.
A desired inductance value can be obtained between the inductance and b.

Furthermore, conventionally, there is a printed coil (C) in which a spiral or zigzag conductor is fixed to both surfaces of an insulating substrate (eg, a magnetic substrate).

FIGS. 5A to 5C show conventional printed coils C in which spiral conductors are fixed to both surfaces of an insulating substrate. However, Figure 5 (A) is a plan view, Figure 5 (B)
is a side sectional view taken along the chain line B-B', and FIG. 5(C) is a bottom view. In this printed coil, 6 is an insulating substrate made of ceramics, resin, or the like. Reference numeral 4 denotes a through hole formed through the insulating substrate 6.

Reference numeral 5 denotes a spiral-shaped conductor, which is fixed to both surfaces of the insulating substrate 6 by a method such as printing conductor paste, and has a spiral shape on one surface and a spiral shape on the other surface. is electrically connected to °C through through hole 4.
There is. This printed coil can obtain a desired inductance value between the spiral-shaped end 5a on one surface of the insulating main substrate 6 of the conductor 5 and the spiral-shaped end 5b on the other surface.

The two conventional printed coils mentioned above have an insulator substrate 1
A similar printed coil can be formed at 1^°C by using a magnetic substrate or the like instead of 6 to 6. Further, a similar printed coil can also be formed by fixing a zigzag-shaped conductor in place of the spiral-shaped conductors 2 to 5.

(Problems to be Solved by the Invention) However, it has been difficult to put into practical use C1, which is a printed coil in which a spiral or zigzag conductor is fixed to the surface of a dielectric substrate, for the following reasons. there was.

That is, the equivalent circuit of a printed coil C in which a spiral or zigzag conductor is fixed to the surface of a substrate can be expressed as shown in FIG.

This is because in the case of a printed coil with conductors fixed to seven surfaces of the board, there is stray capacitance Cp between the conductor lines.
Further, in the case of a printed coil in which conductors are fixed to both surfaces of the substrate, stray capacitance Cp occurs between the conductor lines and between the conductor on one surface and the conductor on the other surface.

When a C insulator substrate or a magnetic substrate is used as the substrate, the stray capacitance Cp is small, but when a dielectric substrate is used, the stray capacitance Cp naturally becomes very large. The self-resonant frequency 10 is as follows. Therefore, when the C stray capacitance cp increases due to the use of a dielectric substrate, the self-resonant frequency f0 decreases and becomes C. This printed coil does not function as a coil at frequencies higher than the self-resonant frequency, but instead functions as a conode. Therefore, when the self-resonant frequency f0 is lowered by using a dielectric substrate, the frequency Characteristics deteriorate and C is removed.

In other words, a printed coil C in which a spiral or zigzag conductor is fixed to the surface of a dielectric substrate has a self-resonant frequency f due to a large stray capacitance Cp. is low;
Its poor frequency characteristics made it difficult to put it into practical use.

Until now, printed coils made by fixing spiral or zigzag conductors on the surface of a dielectric substrate having a dielectric constant of 20 or more have hardly been put to practical use.

However, when a dielectric substrate is used for LC composite parts, etc., it is strongly desired to form a printed coil on the surface of the dielectric substrate.

(Means for Solving the Problems) The present invention is a printed coil that fixes a spiral (8-zigzag) conductor on the surface of a dielectric substrate, which has hitherto been difficult to put into practical use. The purpose is to put it into practical use.

As a means for achieving this, the printed coil of the present invention has a conductor in which two or more spiral-shaped 1, -LL zigzag shapes are connected in series, and is fixed to the surface of a dielectric substrate. That is, in the printed coil of the present invention, a desired inductance value is not formed by one continuous vortex frame-shaped (or zigzag-shaped conductor), but by two conductors connected in series.
The conductor was divided into eight or more spiral-shaped (or zigzag-shaped) conductors.

For example, a desired inductance value can be obtained by connecting a first coil portion and a second coil portion each consisting of two spiral or zigzag conductors.
When the coil portion is equally divided into two parts to form a C, the equivalent circuit is shown in FIG.

However, Ll is the inductance value of the first coil section, L2
is the inductance of the second coil section (L=L).

+L2), CpI is the stray capacitance of the first coil section, and CF2 is the stray capacitance of the second coil section.

By the way, if we compare the total stray capacitance Cp that enters this printed coil with the stray capacitance Ca that enters the printed coil whose inductance value is formed by a continuous spiral or zigzag conductor, we get the following. become that way. First, if the inductance value is divided into two equal parts, the first coil part and the second coil part, forming a C, the size of the conductor in each coil part will be about % smaller than if it were formed with one conductor. Stray capacitance (:, pl and Cpt are approximately equal to the stray capacitance Ca. On the other hand, the stray capacitance Cp is a series connection of the stray capacitances Cpl and Cp, but they have the same size) If two capacitors are connected in series, the capacitance becomes A, so the stray capacitance -1cp is the stray capacitance Cp, and '0
"C is % of pl. Therefore, C1 is the stray capacitance CpI/'i that enters this printed coil as a whole, and the inductance value is formed by one continuous spiral or zigzag conductor. The floating capacitance tCa entering the printed coil is approximately A.

In other words, the printed coil of the present invention is produced by dividing a desired inductance value into two or more spiral-shaped or zigzag-shaped conductors connected in series. Despite using C, it is possible to keep the floating capacitance gap extremely small. Therefore, it is possible to prevent the C1 self-photographing frequency fo from decreasing, and the frequency characteristics are improved.

(Explanation of Examples) Hereinafter, implementation ff11 of the present invention will be described with reference to the drawings.

FIGS. 1A and 1B show a printed coil according to an embodiment of the present invention. However, Fig. 1 (A)
1 is a plan view, and FIG. 1(B) is a side cross-sectional view of the chain and I CC' portion. In this printed coil, the dielectric substrate is made of C16'td ceramics, and has a dielectric constant of 240.1, forming eight coil parts, and the other spiral shape forms a second coil part 9. This printed coil can obtain a desired inductance between one end 7a and the other end 7b of the conductor 7.

On the other hand, FIGS. 2A to 2C show printed coils according to other embodiments of the present invention. however,
Figure 2 (LA) is a plan view, Figure 2 (B) is its chain line D -
FIG. 21(C) is a side sectional view of portion D' and a bottom view.

C110 is a ceramic dielectric substrate with a dielectric constant of 240. Thickness 0.411u
It is I. Reference numerals 11 and 12 indicate through holes, which are formed to penetrate through the dielectric substrate 10, respectively.

A conductor 16 is fixed to both surfaces of the dielectric substrate 10, and has a spiral shape that extends from one surface to the other surface through the through hole 11, and from one surface to the other surface. The spiral shapes formed across the other surface are connected in series through the through holes 12. The shape of one vortex of C1 forms the first coil part 14, and the shape of the other vortex forms the second coil part 15. This printed coil is connected to one end 13a of the conductor 16.
A desired inductance value can be obtained between the end portion 13b and the other end portion 13b.

Both of the above-mentioned printed coils according to the present invention are formed by dividing a desired inductance value into two spiral-shaped conductors connected in series, and the stray capacitance icp is extremely small.

Therefore, the C1 self-resonant frequency elfo decreases and C does not occur.
A sufficiently practical frequency characteristic can be obtained.

Figure 6 shows a dielectric substrate with a relative dielectric constant of 240 and a thickness of 0.4a.The vortex is wound twice on one surface of the dielectric substrate and passed through a through hole to the other surface. The frequency characteristics of a printed coil according to the present invention with an inductance of 175 nH consisting of conductors connected in a row (indicated by [L] in the figure), and a winding of 5 turns on one surface and a C-opening surface through a through hole. A comparison is made with the frequency characteristics of a printed coil (shown in (b) in the figure), which does not belong to the present invention and has an inductance value of 75 nH and is made of a spiral conductor wound six times. From this figure, according to the invention, the frequency! It can be seen that the characteristics have been improved.

The above are two embodiments of the printed coil of the present invention,
It goes without saying that design changes may be made without departing from the spirit of the present invention. For example, the material, dielectric constant, thickness, etc. of the dielectric substrates 6 to 10 are arbitrary, and are not limited as in the above embodiments. In addition, the conductors 7 to 1 and 6 are connected in series with two rectangular spiral shapes each [each constitutes two coil parts], but the conductors 7 (e) constituting the coil part (e) The shape of the coil is not limited to a rectangular spiral shape, but may be a circular spiral shape, a zigzab shape, etc. Furthermore, the number of coil portions formed by the conductors 7 to 13 with the "C" groove is limited to 21. There is no limitation, and it may be 21 or more.

(Effects of the Invention) As is clear from the above explanation, the printed coil of the present invention has a conductor in which two or more spiral or zigzag shapes are connected in series and is fixed to the surface of a dielectric substrate. It is something. As a result, the printed coil of the present invention has a small stray capacitance Cp even though it uses a C attracting substrate as a substrate, so that the self-coherent frequency f
. There is no decrease in C, and sufficiently practical frequency characteristics can be obtained.

[Brief explanation of drawings]

FIG. 1(A) is a plan view showing a printed coil according to an embodiment of the present invention, FIG. 1(B) is a side sectional view taken along the dashed line CC', and FIG. A plan view showing a printed coil according to another embodiment (in Fig. 2) is indicated by the chain line D.
- A side sectional view of the D' portion, FIG. 2(C) is a bottom view, FIG. Figure 4 (A) is a plan view showing a conventional printed coil;
FIG. 4(B) is a side sectional view taken along the chain line B-B',
FIG. 5(C) is a bottom view thereof, FIG. 6 is an equivalent circuit diagram of a conventional printed coil, and FIG. 7 is an equivalent circuit diagram of a printed coil according to the present invention. 6.10... Dielectric substrate, 7.13...
・・・・・・4 Red 8.14・・・・・・First coil part, 9.15・・・・・・Second coil part.

Claims (1)

[Claims] A printed coil comprising a conductor fixed to the surface of a dielectric substrate, characterized in that the conductor is composed of two or more spiral or zigzag shapes connected in series.