JPH11243014A - Inductor - Google Patents

Abstract

(57) [Problem] In a conventional two-dimensional inductor, it is difficult to obtain a sufficiently large inductance value while reducing the size. SOLUTION: A conductor line 23 for forming an inductance, which is formed on a dielectric substrate 22 and has a closed curve shape satisfying at least one of predetermined conditions (1) to (3), Terminal conductor for external connection connected to both ends
24a and 24b. (1) A closed curve arranged in a square frame and symmetrical with respect to two diagonals of the frame. (2) Four closed curves are connected in a predetermined procedure,
A closed curve placed in a square frame and symmetrical with respect to two diagonals of the frame. (3) A closed curve obtained by reducing or enlarging at least a part of the inside of the frame or the large frame and deforming the closed curve of (1) or the closed curve of (2) on a plane or a curved surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inductor suitable for a printed circuit such as a multi-layer circuit board or a multi-chip module / hybrid circuit and capable of obtaining a large inductance in a two-dimensional shape.

[0002]

2. Description of the Related Art As shown in a schematic diagram of a principle in FIG. 3, an inductor generally has a closed annular conductor wire 1 through which a current I is formed, which is formed so as to extend over a single surface. And a magnetic flux .PHI.

As shown in FIG. 4 which is a schematic diagram similar to FIG. 3, the inductor has an ideally infinite space around an annular conductor wire 1 having a diameter D. Specifically, since a space around a thickness of about D and a diameter of about 2D, which are approximately the same size as the stretched surface, is required, the configuration usually has a three-dimensional shape.

[0004]

As described above, in order to secure the cross magnetic flux Φ with respect to the area of the annular conductor wire 1 and the surface on which the conductor wire 1 is stretched, the inductor has the same size as this area. Since a space around the size is required, a three-dimensional shape is usually required. In contrast,
In order to reduce the size of the inductor and realize a structure with a lower dimension, for example, an inductor with a two-dimensional shape, a thick-film printing technology has conventionally been used for forming an inductor that forms part of an electronic circuit on a multilayer circuit board or the like. And thin film technology 2
Forming in a dimensional shape has been performed.

[0005] However, in this case, simply forming a simple annular conductor wire restricts the space above and below the annular conductor wire, so that the cross magnetic flux decreases and the loss increases, and the inductance value increases. Because of the drawback of being small, it has been difficult to secure a sufficient inductance value while reducing the size.

[0006] If the two-dimensional shape is forcibly reduced in thickness with respect to the surface on which the annular conductor wire is stretched, the magnetic flux crossing the stretched surface is reduced, and the inductance value is reduced. This is because the Q value also deteriorates due to the loss.

On the other hand, conventionally, as an inductor for obtaining a desired inductance in a two-dimensional shape while compensating for the above-mentioned disadvantage to some extent and compensating for the disadvantage,
For example, a spiral inductor whose schematic configuration is shown in a perspective view in FIG. 5, a meander-type inductor whose schematic configuration is also shown in a perspective view in FIG. 6, or a microstrip line whose schematic configuration is shown in a perspective view in FIG. It has been known.

In the spiral inductor shown in FIG. 5, a conductor wire 3 is arranged in a spiral shape on a substrate 2, and the mutual inductance is used to increase the inductance value even a little. However, there is no improvement in the reduction of the cross magnetic flux due to the limitation of the thickness as the inductor, and there is a problem that the effect of improving the number of turns of the conductor wire 3 is small.

In the meander type inductor shown in FIG. 6, conductor wires 5 are arranged on a substrate 4 in a zigzag pattern.
The purpose is to secure the length of the conductor wire 5 even a little. However, such a configuration is not an essential improvement, and it is only empirically known that the inductance value slightly increases, and there is a problem that a sufficient inductor value cannot be obtained. Was.

Further, as shown in FIG. 7, when one end of a microstrip line 7 formed on a substrate 6 is short-circuited by a via conductor 8 or the like to form an inductor, the inductor is compared with a spiral inductor or a meander type inductor. Via conductor 8
The thickness of the substrate 6 and the length in the length direction of the microstrip line 7 are required to secure the dimensions of the microstrip line 7, and the efficiency of the used space is further reduced, for example, the inductance value is small in relation to the practical characteristic impedance. There was a problem that it was not good.

The present invention has been completed in view of the above circumstances, as a result of the inventor's intensive research.
It can be formed using technologies that can be easily applied to the production of multilayer circuit boards, such as thick-film printing technology and thin-film formation technology, and is suitable for forming on various circuit boards in response to high integration and high-density mounting. Despite having a two-dimensional shape,
It is an object of the present invention to provide an inductor capable of obtaining a larger inductance than an inductor having a three-dimensional shape.

[0012]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention reduces the inductance value, which is about the same as that of a three-dimensionally shaped inductor, to a lower dimension, that is, a thickness of approximately two-dimensionally. The present invention proposes means realized by a thin inductor.

[0013] For example, there is an inductor composed of an annular conductor wire having a certain diameter, and a plurality of inductors having the same shape are arranged so as to be separated from each other so as to reduce the influence of each other.
It is assumed that they are connected in series. In this case, the total inductance value is the sum of the inductance values of the respective inductors.

On the other hand, the space required by each of these annular inductors is a space having a diameter of about twice the diameter and a thickness of about the same as described above. If they are on the same plane, the space required by the entire inductor is a space having a thickness approximately equal to the size of this plane and the diameter of the individual inductors. Therefore, in this case, the inductor having the sum of the individual inductance values can be realized by an inductance element having a thickness about the diameter of the individual inductor.
A two-dimensional inductor can be realized.

The present inventor has proposed, as a two-dimensional inductor in which such individual annular inductors are connected to each other, a conductor line for forming an inductor having a closed curve shape satisfying the following condition on a dielectric substrate. It has been found that an inductor having a desired large inductance value with a small size can be obtained by forming, cutting a part thereof, and leading it to the outside by a terminal conductor.

That is, the inductor of the present invention is formed on a dielectric substrate and has a closed-form conductor line having a closed curve shape satisfying at least one of the following conditions (1) to (3): It is characterized by comprising a terminal conductor for external derivation connected to both ends by cutting a part thereof. (1) A closed curve that is arranged in a square frame and symmetrical with respect to two diagonals of the frame. (2) The frame is arranged in a large frame in which four frames are arranged in a square, and an opening is formed at a portion where the diagonal line of the large frame of the closed curve arranged in each frame intersects with the center point side of the large frame. The openings of the closed curves adjacent to each other are connected by auxiliary curves that are line-symmetric with respect to two diagonals of the large frame, and are closed curves that are line-symmetric with respect to two diagonals of the large frame. (3) At least a part of the inside of the frame or the inside of the large frame is reduced or enlarged, and the closed curve of (1) or the (2) is closed.
Is a closed curve obtained by deforming the closed curve on a plane or a curved surface. In the inductor of the present invention, a conductor line for forming an inductor having a shape of a closed curve that satisfies any of the above conditions is formed on the same surface as the surface or inside of the dielectric substrate,
A part of the conductor is cut off, and a terminal conductor for external derivation is connected to both ends thereof, and an inductance is formed by an annular portion of the conductor wire. With a thickness and a line width, the dielectric substrate can be easily formed and arranged on a predetermined same surface of the dielectric substrate by using an appropriate technique such as a thick film printing technique or a thin film forming technique.

If the conductor line for forming the inductance has a shape of a closed curve which satisfies the above-mentioned conditions, the closed curve can be arbitrarily formed on the same surface of the dielectric substrate without intersecting according to the rules shown in the above-mentioned conditions. Since it is a closed curve that can be lengthened, the length of the closed curve can be extremely long and arbitrarily set, and the annular portion contributing to the inductance can be efficiently arranged, thereby easily achieving a desired high inductance value. Can be realized.

As described above, according to the inductance of the present invention, at least one of the above (1) to (3) is provided on the dielectric substrate.
Is formed by forming a conductor line for inductance formation having a closed curve shape that satisfies the two conditions, so that the inductance is formed on a plane of a limited area square or on a plane or a curved surface obtained by deforming the square. The length of the conductor wire for use is extremely long and arbitrarily set as the shape of each closed curve, and the annular portion contributing to the inductance can be efficiently arranged. It is possible to obtain an inductance value equal to or higher than.

Further, according to the inductor of the present invention, by applying the condition (2) based on the above condition (1), the area of the square frame and the area of the large frame are almost doubled when the area is the same. The length of the conductor wire for forming the inductance can be provided, and the inductance formed by the annular portion of the conductor wire can easily realize an inductor having a high inductance value. Further, by applying the condition (3), it is possible to easily realize an inductor having a desired inductance value not only on the surface or inside flat surface of the dielectric substrate but also on various curved surfaces such as irregularities.

Further, according to the inductor of the present invention, a conductor wire for forming an inductance is formed on the same surface of the surface or inside of the dielectric substrate, a part thereof is cut, and external lead terminals are provided at both ends. Since these conductor lines and terminal conductors can be formed by a technique that can be easily applied to the manufacture of circuit boards, such as a thick-film printing technique or a thin-film forming technique, since they are configured by connecting conductors, various types of It can be formed on the surface of the circuit board or on the dielectric layer inside to support high integration and high density mounting,
Moreover, it is possible to realize a high inductance value which is substantially equal to or higher than that of an inductor having a substantially two-dimensional shape and a higher dimension.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an inductor according to the present invention will be described with reference to the drawings. FIGS. 1A to 1D are plan views each illustrating an example of an embodiment of the inductor of the present invention. First, as shown in FIG.
In a square frame 11 (shown by a solid line), a closed curve 13 symmetrical with respect to two diagonal lines 12 (shown by broken lines) of the frame 11 is arranged. Here, a circle is illustrated as the closed curve 13. In this case, the x-axis is arranged in parallel with the two opposing sides with the center point of the frame as the origin, and the y-axis is arranged perpendicular to the x-axis (respectively). (Indicated by a dashed line), the closed curve 13 is also line-symmetric with respect to these x-axis and y-axis.

Here, in such a simple closed curve 13,
Since a large inductance value to be realized by the inductor of the present invention cannot be obtained depending on the annular portion, the closed curve 13 is temporarily set to a zero-order closed curve.

That is, if a circle having a radius r = 1/3 is drawn at the center of a square frame 11 having a side of 1 as a zero-order closed curve, the closed curve 13 (circumferential circle) in this state is drawn. ) Is 2πr × 2 ** i = 2πr × 2 ** 0 = 2πr.

Therefore, as shown in FIG.
Assuming that four squares 11 are arranged in a square shape without any gap, a square frame 14 is formed. In this new square frame 14, when the x-axis and the y-axis are arranged with the center as the origin, the first, second, and
The closed curve 13 in FIG. 1A is arranged in the third and fourth quadrants.

As described above, when the four square frames 11 on which the zero-order closed curves 13 are arranged are arranged in a square shape without gaps to form a square frame 14, the sum of the lengths of the circumferences of the four circles in this state is obtained. Becomes four times the zero-order closed curve 13, and becomes 2πr × 4.

Next, as shown in FIG. 1C, a diagonal line is formed around the intersection between the two diagonals 15 (shown by broken lines) of the new square frame 14 of each closed curve 13 on the origin side. An opening is formed by hollowing out a line symmetrically with respect to 15, and four ends of each of the openings of the closed curve 13 adjacent to each other are line symmetrical with respect to the diagonal 15, for example, four auxiliary curves 16, A new closed curve 17 is formed by connecting the ends of the openings with substantially straight parallel conductor lines or the like.
Assuming that this is a first-order closed curve, the length of the closed curve 17 is substantially equal to the sum of the lengths of the closed curves 13 forming the four annular portions.

[0027] Thereby, it is arranged in the square frame 14,
A closed curve 17 symmetrical with respect to two diagonals 15 of the frame 14 is obtained. For the inductor of the present invention, for example, the closed curve 17 becomes a closed curve that satisfies the condition (1), and by cutting a part thereof and connecting terminal conductors to both ends thereof,
The inductance is formed by the four annular portions.

In this state, the sum of the lengths of the annular portions contributing to the overall inductance hardly changes, and is approximately 2πr × 4.

Here, in order to standardize the square frame 14 so that one side is a square, if the entire length is 1/2 times (1/4 times the area), the annular shape contributing to inductance is obtained. The sum of the lengths of the parts is halved and is approximately (2πr × 2
** 2) / 2 = 2πr × 2.

The order is sequentially increased according to such a rule.
That is, four square frames are sequentially combined, and four
The cutting, connecting, and reducing operations are repeated in one circumference. With each repetition, the sum of the lengths of the annular portions contributing to the inductance in the closed curve drawn in a square frame having one side continues to increase by about twice. If the dimension when i is repeated i times is i, the sum of the lengths of the annular portions contributing to the inductance at that time is approximately 2πr × 2
** i. Thus, i can be arbitrarily increased, and the sum of the length of the closed curve and the length of the annular portion contributing to the inductance can be arbitrarily increased.

Next, by using the closed curve 17 shown in FIG. 1C, as shown in FIG.
To form a square large frame 18
Opening portions are formed symmetrically with respect to the diagonal 19 at portions where the diagonal 19 of the large frame 18 and the center point side of the large frame 18 intersect with each other, and the closed curves 17 adjacent to each other The two ends of the opening of the large frame 18
Are connected by four auxiliary curves 20 symmetrical with respect to. This is temporarily set as a secondary closed curve.

As a result, a closed curve 21 symmetrical with respect to two diagonal lines 19 of the large frame 18 arranged in the square large frame 18
Is obtained. For the inductor of the present invention, for example, the closed curve 21 becomes a closed curve that satisfies the condition (2). By cutting a part of the closed curve and connecting a terminal conductor to both ends thereof, an inductance is formed by 16 annular portions. Will be done.

At this time, the length of one side of the large frame 18 is twice the length of the frame 14, and the length of the closed curve 21 is substantially equal to the sum of the lengths of the four closed curves 17. . Therefore, if this large frame 18 is reduced to で in length and 面積 in area, the large frame 18 becomes the same size as the original frame 14, and the length of the closed curve 21 becomes the length of the closed curve 17. , And a closed curve having a length almost twice as long as having four times the annular portion inside a square having the same area can be arranged with regularity. Therefore, in this case, for an inductor having four annular portions having the shape of the closed curve 17, the closed curve
An inductor having 16 annular portions having the shape of 21 has almost twice the inductance value when formed in the same area.

Then, by arbitrarily setting the magnification for reducing or enlarging the frame 14 or the large frame 18, a conductor line having a shape of a closed curve obtained as a result is formed, and a part thereof is cut and both ends thereof are cut. By connecting the terminal conductor,
A two-dimensional inductor having any desired inductance value can be obtained.

Further, by reducing or enlarging at least a part of the inside of the frame 14 or the large frame 18 with respect to the closed curve 17 arranged in the frame 14 or the closed curve 21 arranged in the large frame 18, a predetermined rule is obtained. The closed curve arranged with the property can be deformed on a plane, and it can be made a closed curve deformed on a curved surface instead of a plane, in this case, not only on the flat surface of the dielectric substrate but also various irregularities such as irregularities It is possible to easily realize an inductor having a desired inductance value on the curved surface.

The inductance value of the inductor is
It can also be changed by changing the width or thickness of the conductor wire, and it is possible to obtain an inductor having a desired inductance value by adjusting the inductance value in a trade-off with the Q value.

FIG. 2 is a perspective view showing an example of the inductor of the present invention realized as described above.

In FIG. 2, reference numeral 22 denotes a dielectric substrate. Here, an example is shown in which a square plate-shaped dielectric substrate is used, but various dielectrics such as the surface of a multilayer circuit board and an internal dielectric layer can be used as the dielectric substrate 22. The shape of the surface may be not only a flat surface but also various curved surfaces such as irregularities.

Reference numeral 23 denotes a conductor for forming an inductance having a shape corresponding to the closed curve 17 shown in FIG.
It is preferable that the line width of the conductor wire 23 be as thin as the line width of the closed curve 17. The conductor wires 23 are arranged in the shape of a closed curve 17 on the same surface as the surface or inside of a dielectric substrate 22 having a plane or a curved surface having a finite area. And
Reference numerals 24a and 24b denote terminal conductors which are obtained by cutting a part of the conductor wire 23 and connecting to both ends thereof for external connection to an external circuit. Thereby, the terminal conductor 24a
The inductor of the present invention in which a desired inductance is formed by the annular portion of the conductor wire 23 between 24b is obtained.

Here, the inductor value of the inductor shown in FIG. 2 will be described. According to the inductor of the present invention as shown in FIG. 2, the magnetic field that intersects with the plane formed by the annular portion of the conductor wire 23 ideally occupies an infinite space, but is particularly distributed in a large amount around the annular portion. doing.

The diameter of the annular portion of the conductor wire 23 is D, and the wire diameter is d.
Then, when D (cm) ≫d (cm), the inductance value L ₀ (nH) of each annular portion is L ₀ = 2πD ｛l
n (D / d) + 0.08 °.

Here, the same space as the diameter D of the annular portion is set above and below the annular portion, and the magnetic flux crossing the surface where the annular portion is stretched is limited to only the space existing in the set space.
In this case, the inductance value L ₁ is slightly lower than L ₀ , but is on the same order.

Next, the following operation is performed in the range of In (D / d) ≫0.08. The diameter D of the annular portion is set to 1/2, and the area of the annular portion is set to 1/4. Then, the four reduced annular portions are connected in series with the coupling being negligible to each other.

Then, the overall inductance value L ₂ is
About L ₂ = 4 × 2π (D / 2) ln ｛(D / 2) / d
+0.08｝. The difference between the inductance value L ₁ of the original,
2πD ｛ln (D / d) +0.08｝ −2 × 2πDln2, and when the diameter D of the annular portion is approximately four times or more the diameter d of the conductor wire, the ingactance value increases up to about twice. . On the other hand, the thickness of this inductor is set to be the same as the diameter of the annular portion, so
It becomes 2.

The portion of the auxiliary conductor line composed of parallel conductor lines for connecting the annular portions does not contribute to the inductance value because the opposing current is almost on the same line. Further, actually, the amount of increase in the inductance value due to the influence of the mutual inductance is smaller than that described above.

The terminal conductors 24a and 24b are used to electrically connect to an external electric circuit or electronic circuit. Alternatively, pressure contact may be used, or a through conductor such as a via conductor or a through-hole conductor disposed inside the dielectric substrate 22 may be used, and an appropriate conductor for electrical connection may be used according to the specification.

The present invention is not limited to the above examples, and various changes and improvements can be made without departing from the scope of the present invention. For example, FIG.
One or some of the annular portions of the closed curve 21 shown in FIG.

[0048]

According to the inductor of the present invention, a conductor for forming an inductor having a shape of a closed curve, which is formed on a dielectric substrate and satisfies at least one of the above conditions (1) to (3); An annular portion that forms an inductance on a square plane of limited area or on a plane or curved surface deformed from a square because it consists of a terminal conductor connected to both ends by cutting a part of the wire The length of the conductor wire having the shape can be set to be extremely long and arbitrarily as the shape of each of the above-mentioned closed curves, and it is possible to obtain a large inductance value equal to or more than that of a three-dimensional inductor while having a substantially two-dimensional shape. it can.

Further, according to the inductor of the present invention, by applying the condition (2) based on the above condition (1), when the area of the square frame and the area of the large frame are the same, it is almost doubled. The length of the conductor wire can be formed, and an inductor having a large inductance value can be easily realized by appropriately setting the reduction or enlargement magnification. Furthermore, by applying the condition (3), it is possible to easily realize an inductor having a desired inductance value not only on the surface or inside flat surface of the dielectric substrate but also on various curved surfaces such as irregularities.

Further, according to the inductor of the present invention, since the conductor is formed by forming the conductor wire of a predetermined shape and the terminal conductor connected thereto on the dielectric substrate,
These conductor wires and terminal conductors can be formed by a technology that can be easily applied to the manufacture of circuit boards such as a thick film printing technique or a thin film formation technique. In addition to the conventional two-dimensional inductors, which can be formed on top of high-density and high-density mounting, and have the smallest dimensions, not only conventional two-dimensional inductors but also higher-dimensional inductors It is possible to realize a large inductance value equal to or larger than.

[Brief description of the drawings]

FIGS. 1A to 1D are plan views each illustrating an example of an embodiment of an inductor according to the present invention.

FIG. 2 is a perspective view showing an example of an embodiment of the inductor of the present invention.

FIG. 3 is a schematic principle diagram for explaining an inductor.

FIG. 4 is a schematic principle diagram for explaining an inductor.

FIG. 5 is a perspective view showing a schematic configuration of a spiral inductor.

FIG. 6 is a perspective view illustrating a schematic configuration of a meander-type inductor.

FIG. 7 is a perspective view showing a schematic configuration of an inductor in which one end of a microstrip line is shortened.

[Explanation of symbols]

 14 ・ ・ ・ ・ ・ ・ Frame 15, 19 ・ ・ ・ ・ Diagonal line 16, 20 ・ ・ ・ ・ ・ ・ Auxiliary curve 17, 21 ・ ・ ・ ・ Closed curve 18 ・ ・ ・ ・ ・ ・ ・ Large frame 22 ・ ・ ・.... Dielectric substrate 23 ........ Conductor wires 24a, 24 .... Terminal conductor

Claims (1)

[Claims] 1. A method according to claim 1, which is formed on a dielectric substrate and has the following condition (1):
And (3) a conductor wire for inductance formation having a closed curve shape that satisfies at least one of (3) and a terminal conductor for external derivation connected to both ends by cutting a part of the conductor wire. Features inductor. (1) A closed curve that is arranged in a square frame and symmetrical with respect to two diagonals of the frame. (2) The frame is arranged in a large frame in which four frames are arranged in a square, and an opening is formed at a portion where the diagonal line of the large frame of the closed curve arranged in each frame intersects with the center point side of the large frame. The openings of the closed curves adjacent to each other are connected by auxiliary curves that are line-symmetric with respect to two diagonals of the large frame, and are closed curves that are line-symmetric with respect to two diagonals of the large frame. (3) At least a part of the inside of the frame or the inside of the large frame is reduced or enlarged, and the closed curve of (1) or the (2) is closed.
Is a closed curve obtained by deforming the closed curve on a plane or a curved surface.