JPH04152507A - Inductor - Google Patents

Abstract

PURPOSE:To obtain an induction having a value of high figure of merit Q in high-frequency regions and small stray capacitance by a method wherein conductor patterns of almost the same shape are piled up to overlap with insulators interposed to constitute coils, respectively, so that the coils may be connected electrically in parallel. CONSTITUTION:Conductor patterns 2,3 of almost the same shape are piled up to overlap with insulators 1 interposed: these conductor patterns 2,3 constitute the respective coils which are connected electrically in parallel. For example, conductor patterns of the same shape are provided at the centers of the top and bottom faces of an insulator sheet 1. A material of low permittivity such as polyimide of 20mum or less thickness is used for the insulator sheet 1. The conductor patterns 2, 3 are made helical and arranged to overlap with the insulator sheet 1 interposed. The one-side ends of the conductor patterns 2,3 are connected to extract electrodes 5a, 6a provided at the upper and lower left ends of the insulator sheet 1, and the other-side ends to extract electrodes 5b, 6b provided at the upper and lower right ends of the insulator sheet 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inductor used in constructing an electronic circuit.

Some inductors are manufactured by forming a conductive pattern on a flat surface of an insulating sheet or the like.

In this case, in order to increase the value of the good dust Q of the inductor, a method is adopted in which the conductor thickness of the spiral conductor pattern is increased to reduce the resistance R of the inductor, or an insulator sheet etc. A method has been adopted in which the inductance L of the inductor is increased by alternately stacking patterns and connecting the conductor patterns in series to form a coil.

However, the method of increasing the conductor thickness of the conductor pattern is limited to high frequency ranges (e.g., several 100 Mtlz to several G).
Due to the skin effect that occurs at high frequencies (Hz), current flows concentrated on the surface of the conductor pattern, resulting in a rapid increase in resistance.As a result, there is a limit to the improvement of the good dust Q of inductors in the high frequency range. Ta. In addition, a method in which insulator sheets or the like and conductor patterns are alternately laminated and the conductor patterns are connected in series to form a coil shape generates a large stray capacitance C due to potential difference between each conductor pattern. There was a problem that this stray capacitance C and the inductance L of the coiled conductor pattern resonated, so that it could not be used in a high frequency region.

Therefore, an object of the present invention is to provide an inductor that has a large good dust Q value even in a high frequency range and has a small stray capacitance.

In order to solve a problem that is more than just a sword, the inductor according to the present invention has conductor patterns of approximately the same shape stacked so as to overlap with each other with an insulator interposed therebetween, and each of the conductor patterns It is characterized in that it constitutes a coil, and each of the coils is electrically connected in parallel.

■ In the above configuration, coils made of conductor patterns of approximately the same shape overlap with each other via an insulating layer, and each coil is electrically connected in parallel, so no potential difference occurs between the coils; Stray capacitance does not occur due to Moreover, the surface area of the conductive pattern increases, suppressing the increase in resistance value due to the skin effect that occurs in the high frequency region, and improving the quality of dust.

DESCRIPTION 1 Hereinafter, embodiments of an inductor according to the present invention will be described with reference to the accompanying drawings.

[First embodiment, FIGS. 1 to 4] As shown in FIGS. 1 and 2, the inductor has conductive patterns 2.3 of the same shape at the center of the upper and lower surfaces of the insulating sheet 1.
is provided.

The insulator sheet 1 is made of a material with a low dielectric constant ε, such as a polyimide material with a thickness of 20 μm or less, to suppress the generation of stray capacitance.

The conductor patterns 2.3 have a spiral shape and are arranged so as to overlap with each other with the insulator sheet 1 in between.

One end of the conductive pattern 2.3 is electrically connected to the extraction electrodes 5a, 6a provided on the left end of the upper and lower surfaces of the insulating sheet 1, and the other end is connected to the upper and lower surfaces of the insulating sheet 1. It is electrically connected to extraction electrodes 5b and 6b provided at the right end. An insulating material 4 such as polyimide extending from the center of the vortex of the conductor pattern 2.3 to the outside of the vortex insulates the drawn-out portion of the conductor pattern 2.3 from the vortex-forming portion. Further, the extraction electrodes 5a and 6a and the extraction electrodes 5b and 6b are electrically connected by external electrodes (not shown).

These, the conductor pattern 2.3 and the extraction electrode 5a,
5b, 6a, and 6b are formed by applying a paste such as Heg+Ag-Pd to the surface of the insulating sheet 1 by printing or other means.

In the inductor thus obtained, the coils made of the same-shaped conductor patterns 2 and 3 are overlapped with the insulator sheet 1 in between, and since each coil is electrically connected in parallel, a potential difference occurs between the coils. Therefore, stray capacitance due to potential difference does not occur. Therefore, the inductor can obtain excellent frequency characteristics without resonance occurring in the high frequency range. Moreover, the surface area of the conductor pattern that makes up the coil has increased compared to conventional inductors.
Since the increase in resistance value due to the skin effect that occurs in the high frequency region is suppressed, the improvement in the good dust Q of the inductor is significantly improved.

In Figures 3 and 4, the insulator seam) 1 has a thickness of 6
A solid line 10.12 shows the frequency characteristic measurement results of good dust Q when a μm polyimide material is used.

For comparison, an inductor with the same inductance value, which is a conventional technique in which the conductor thickness of the conductor pattern is increased to improve the good dust Q, is shown by dotted line 11, and the insulator sheet etc. and the conductor pattern are shown by dotted line 11. Dotted lines 13 indicate inductors having the same inductance value that are alternately stacked to improve the quality of dust Q.

[Second Example, Figures 5 to 8] A second embodiment will be described together with a manufacturing method.

First, as shown in FIG. 5, a spiral conductor pattern 22 is provided at the center of the upper surface of the insulator sheet 21 by printing or other means. Furthermore, an extraction electrode 23 electrically connected to the end of the conductor pattern 22 is provided at the left end of the insulator sheet 21, and an extraction electrode 24 is provided at the right end.

Next, as shown in FIG. 6, the conductor pattern 22 is covered with an insulating film 25 made of polyimide resin or the like. At this time, the terminal end 22a and the right part 22 of the conductor pattern 22
Holes are formed in the insulating film 25 so that the holes b, 22c, 22d, and 22e are exposed from the insulating film 25. Note that, as shown in FIG. 7, the insulating film 27 has a rib (27a)
may be set so that the terminal end 22a and the right portions 22b to 22e of the conductive pattern 22 are exposed from the insulating film 27.

Next, as shown in FIG. 8, a conductor pattern 29a,
29b and 29c are applied by printing or other means so as to overlap the conductive pattern 22 with the insulating film 25 interposed therebetween.

At this time, the terminal end 22a and the right portions 22b to 22e of the conductive pattern 22 exposed from the insulating film 25 are electrically connected to the conductive patterns 29a, 29b, and 29c, respectively.

The inductor thus obtained consists of two coils, namely:
A coil and conductor patterns 29a and 29b each consisting of a part of the conductor pattern 22 and the conductor pattern 29c.

29c and a coil formed from a part of the conductor pattern 22. These two coils are connected to the insulating film 2.
5 and are electrically connected in parallel. The function and effect of this inductor are similar to those of the first embodiment.

[Other Examples] Note that the inductor according to the present invention is not limited to the above embodiments, and can be variously modified within the scope of the gist. In particular, the conductor pattern may have a structure in which three or more conductor patterns are connected in parallel.

As is clear from the above explanation, according to the present invention, coils made of conductor patterns of approximately the same shape are stacked with an insulating layer interposed between them, and the coils are electrically connected in parallel, so that even in a high frequency range No stray capacitance occurs, and there is no increase in resistance due to skin effect. The magnetic flux generated in each coil interlinks with other coils to increase the amount of good dust Q. Therefore, an inductor can be obtained which has a large good dust Q value even in a high frequency range and has a small stray capacitance.

[Brief explanation of drawings]

1 to 4 show a first embodiment of an inductor according to the present invention, FIG. 1 is a plan view showing an insulator sheet provided with a conductor pattern, and FIG. An exploded perspective view showing the structure with the conductor pattern, and FIGS. 3 and 4 are graphs showing the frequency characteristics of the good dust Q, respectively. 5 to 8 show a second embodiment of the inductor according to the present invention, in which FIG. 5 is a plan view showing an insulator sheet provided with a first-layer conductor pattern, and FIGS. 7
This figure is a plan view showing the insulating sheet after coating the insulating film, and FIG. 8 is a plan view showing the insulating sheet provided with a second-layer conductor pattern. 1... Insulator sheet, 2.3... Conductor pattern,
21... Insulator sheet, 22... Conductor pattern,
25.27... Insulating film, 29a, 29b, 29c
...Conductor pattern. Patent applicant Murata Manufacturing Co., Ltd.

Claims (1)

[Claims] 1. An inductor characterized in that conductor patterns having substantially the same shape are stacked so as to overlap each other with an insulator in between, each of the conductor patterns forming a coil, and each of the coils being electrically connected in parallel.