JP3280019B2 - LC noise filter - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an LC noise filter.

[Prior Art] With the development of electronic technology in recent years, electronic circuits have been widely used in various fields. Therefore, it is necessary to operate each of these electronic circuits stably and reliably without being affected by outside. desired.

However, noise enters such an electronic circuit directly or indirectly from the outside. For this reason, there is a problem that a malfunction often occurs in various electronic devices using the electronic circuit.

In particular, electronic circuits often use a switching regulator as a DC power supply. Therefore, a large noise having various frequency components is often generated in a power supply line of a switching regulator due to a transient current such as switching or a load fluctuation caused by a switching operation of a digital IC to be used. These noises are transmitted to other circuits in the same device via power supply lines or by radiation, causing adverse effects such as malfunctions and lowering of the S / N ratio. May cause malfunction.

In order to remove such noise, various noise filters are generally used in electronic circuits. In particular, in recent years, various types of high-performance electronic devices have been used, and regulations on noise have become increasingly intense. For this reason, a small and high-performance noise filter capable of reliably removing generated noise. The development of is desired.

One of such noise filters has been
The LC noise filter shown in FIG. 22 is widely used. In this LC noise filter, as shown in FIG. 22 (A), two sets of windings 12 and 14 are wound around a core 10, and capacitors 16 and 18 are connected in parallel to both ends of these windings 12 and 14, respectively. It was formed so that.

[Problems to be Solved by the Invention] However, the conventional noise filter requires separately formed windings 12 and 14 and capacitors 16 and 18, so that various types of electronic devices that have been increasingly reduced in size and weight in recent years have been required. There is a problem in that the noise filter itself is large and expensive compared to components.

The conventional noise filter is formed as a lumped constant type as shown in FIG. 22 (B). For this reason,
With this alone, it is not possible to reliably eliminate various types of noise that intrude, especially common mode noise such as switching surges, and normal mode noise such as ripples, and ringing occurs when the capacitance and inductance of capacitors and coils are increased. There was a problem of doing it.

The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a small-sized LC noise filter capable of reliably removing intruding noise without generating ringing or the like. It is in.

[Means for Solving the Problems] To achieve the above object, an LC noise filter according to the present invention comprises: a first insulating sheet having a plurality of folded portions which are alternately folded in opposite directions and stacked; A first conductor provided on one side of the portion so as to form a coil having a predetermined number of turns when the respective folded portions are alternately folded in the opposite direction and stacked, and on the other surface side of each of the folded portions, A second conductor that is provided to be substantially opposed to the first conductor and forms a capacitance between the first conductor and the first conductor. The first and second conductors are relatively opposed with a given opposed width. It is characterized by being formed to face.

Further, the LC noise filter according to the present invention further includes a first insulating sheet having a plurality of folds that are alternately folded in opposite directions and stacked, and on one side of each of the folds, the folds are alternately reversed. A first conductor provided to form a coil having a predetermined number of turns when folded and laminated; and a first conductor provided on the other surface side of each of the folded portions so as to substantially face the first conductor. And a second conductor forming a capacitance between the first and second conductors, wherein the first and second conductors sandwich the second conductor between first conductors located on both sides thereof. Characterized in that they are arranged to face each other.

[Operation] Next, the operation of the present invention will be described.

In the present invention, the plurality of folds constituting the first insulating sheet are alternately folded in the opposite direction to form a laminate, whereby the first conductor provided on one side of each fold is provided with a predetermined shape. A coil having the number of turns is formed and functions as an inductor conductor.

At this time, the second conductor provided on the other surface side of each folded portion so as to substantially face the first conductor forms a capacitance between the first conductor and the first conductor in a distributed constant manner. Guessed.

Therefore, the LC noise filter of the present invention functions as a distributed constant type filter, and the conventional lumped constant type LC
As compared with the noise filter, it is possible to obtain good attenuation characteristics over a relatively wide band, and it is possible to remove various noises without causing ringing. In particular, the LC of the present invention
The noise filter effectively functions the L component and the C component of the distributed constant circuit, and can effectively remove various noises.

Further, since the LC noise filter of the present invention is formed by folding and stacking the folded portions, the manufacturing thereof is simple, small, and low-cost.

In the present invention, the first and second conductors are
By forming it as an inductor conductor provided with input / output terminals at both ends, it can be used as a common mode type LC noise filter.

In addition, the first conductor is formed as an inductor conductor having input / output terminals provided at both ends thereof, and the second conductor is formed as a capacitor conductor provided with a ground terminal. It can also be used as an LC noise filter.

Further, if necessary, a third conductor is provided on one side surface of each of the folded portions of the second insulating sheet so as to substantially face the second conductor via the folded portion, and the first and third conductors are provided. By forming the inductor conductor having input / output terminals at both ends thereof and forming the second conductor as a capacitor conductor having a ground terminal, a common mode LC is provided.
It can also be formed as a noise filter.

Embodiment Next, a preferred embodiment of the present invention will be described in detail with reference to the drawings.

First Embodiment FIGS. 1 to 5 show a preferred example in which the present invention is applied to a three-terminal normal mode LC noise filter.

EXAMPLE When manufacturing an LC noise filter, first, a first insulating sheet 20 shown in FIG. 2 is formed. The first insulating sheet 20 includes a plurality of folded portions 22 that are folded and stacked.
-1, 22-2... 22-8 are continuously arranged via a bent portion 24. Perforations are formed in each of the bent portions 24 in advance to facilitate the bending. Further, although the folded portion 22 of the present invention is formed in a square shape, the shape can be arbitrarily formed as long as the folded portion 22 is laminated on each other when folded.

A first conductor 40 having a pattern shown in FIG. 3A is provided on the front surface 20a side of the first insulating sheet 20.
On the 20b side, the second conductor 50 having the pattern shown in FIG.
Is provided.

The first conductor 40 is provided with each of the folded portions that are continuously arranged.
22-1, 22-2... 22-8, on the surface 20a side, ring-shaped inductor conductors 42-1, 42-2.
7 are provided alternately and continuously in the opposite direction, and when the first insulating sheets 20 are folded alternately and in the opposite direction as shown in FIG. 4
Turn) to form a coil.

Input / output terminals 44a and 44b are provided at both ends of the first conductor 40. In this case, one input / output terminal 44a is
As shown in FIG. 3 (A), it is provided at the lower right corner of the folded portion 22-1. The other input / output terminal 44b is connected to the fold 22-
7 is provided in the lower left corner. Input / output pins 46a, 46b are attached and fixed to these input / output terminals 44a, 44b as external connection conductors.

Further, the second conductor 50 is provided at each of the folded portions 22-1, 22-2.
... Capacitor conductor 5 provided on back side 20b of 22-7
6-1, 56-2 ... 56-7. The capacitor conductors 56-1, 56-2... 56-7 are provided so as to be opposed to the inductor conductors 42-1, 42-2. To form a capacitance between them. Accordingly, when the second conductor 50 is viewed from the back surface 20b side of the first insulating sheet 20, the pattern becomes as shown in FIG. 3 (B). One end of the conductor 50 extends from the folded portion 22-7 to the center of the folded portion 22-8, and a ground terminal 52 to which the ground pin 54 is attached and fixed as an external connection conductor is provided.

In this case, the first conductor 40 and the second conductor 50
Can be formed on the first insulating sheet 20 by various methods such as printing, etching, and plating.
The conductive plate having the pattern shape shown in FIGS. (A) and (B) can be formed by an arbitrary method such as pasting on the first insulating sheet 20.

In this embodiment, the conductors 42 for the inductor and the conductors 44a, 56a of the conductor 56 for the capacitor are formed so as to cover the bent portions 22. Thus, even when the first insulating sheet 20 is soft, the first insulating sheet 20 can be easily and reliably folded at the bent portion 22 where the perforations are formed. When the pattern of each conductor is formed over the bent portion 22, the perforation can be more easily bent by forming perforations on both the conductor and the insulator.

In the present embodiment, the conductors 40 and 50 are
The surface is coated with an insulating layer. The conductor 50
Instead of forming an insulating layer on the surface of the second insulating sheet, a second insulating sheet 30 having the same structure as the first insulating sheet 20 is prepared, and these two insulating sheets 20 and 30 are laminated such that the conductor 50 is sandwiched between them. It may be adhered. In addition, in order to simplify the following description, the following description will be made taking an example in which the second insulating sheet 30 is not used.

Next, as shown in FIG. 1 (A), the insulating sheet 20 having the conductor 40 and the conductor 50 coated on both surfaces thereof is folded.
It is bent in a zigzag shape through 24, and each folded part 22-1, 22-
2 ... 22-8 are laminated. Thus, a laminate 300 shown in FIG. 1B is formed. Each of the ring-shaped conductors 42-1, 42-2,..., 42-7, which are partially notched, overlap each other, and make one conductor a plurality of turns (four turns in the embodiment).
The wound coil is formed, and functions as an inductor having the inductance L1. At the same time, the conductor 50 opposes the first conductor 40 via the insulating sheet 20 and forms a capacitance C therebetween.

Therefore, this LC noise filter functions as a three-terminal LC noise filter of an equivalent circuit as shown in FIG.

At this time, in the stacked body 300 folded as shown in FIG. 1 (B), the pins 46a, 46b, 54 are arranged at equal intervals. This corresponds to the input / output terminal 44 of the first conductor 40 as described above.
This is because the a and 44b and the ground terminal 52 of the conductor 50 are positioned and formed.

Next, as shown in FIG.
Except for the pins 46a, 46b, and 54, molding using a resin such as epoxy is performed to form a final LC noise filter.

In a noise filter having a large number of folding parts 22,
As shown in FIG. 5 (A), each pin 46
The heights of a, 46b, and 54 may not be uniform. In this case,
As shown in FIG. 5B, it is preferable to perform lead forming in which each pin is bent so that each pin is aligned (in-line).

As described above, according to the LC noise filter of the present invention, the first insulating sheet 20 having the first conductor 40 and the second conductor 50 coated on both surfaces thereof is zigzag through the bent portion 24. By folding it into a shape, it is formed in a flat cubic shape. For this reason, it is smaller and lighter than a conventional LC noise filter, and is extremely suitable as a component for electronic circuits, which is required to be smaller and lighter in recent years.

Further, the LC noise filter according to the present invention includes the pins 46a, 46
The b and 54 can be aligned so as to be arranged at a predetermined interval on a straight line (inline). For this reason, attachment of the LC noise filter to the substrate becomes extremely easy. In particular, according to the present invention, since the pin intervals can always be formed to be constant, there is little variation in attenuation characteristics due to irregularities in the pin intervals of the manufactured LC noise filter, and the noise characteristics are substantially uniform and sufficiently small. The filter can be easily mass-produced.

Further, the noise filter of the present invention functions as a three-terminal LC noise filter shown in the equivalent circuit of FIG. 4, and in particular, the capacitance C between the first conductor 40 and the second conductor 50 is a distribution constant. It is presumed that the noise filter is formed in a typical manner, and it is possible to exhibit an excellent attenuation characteristic which is not provided in the conventional lumped-constant type noise filter.

The present inventor further studied and found that the position of the second conductor 50 functioning as a grounding conductor facing the first conductor 40 functioning as a current-carrying inductor was determined by the attenuation characteristic of the noise filter. It has been found to have a significant effect. That is, the second conductor 50 may be formed so as to face not only the entire first conductor 50 but also a part thereof as necessary. In this case, it was confirmed that excellent attenuation characteristics could be obtained by disposing the second conductor 50 at a position closer to the input / output terminal of the first conductor 40 in terms of an electric circuit as in the present embodiment.

Further, how to form the ground pin 54a of the second conductor 50 was examined. As a result, it was confirmed that it is preferable to dispose the ground pin 54 at a position closer to one of the input / output pins 46a or 46b in terms of an electric circuit.

FIG. 6 shows the values of the first conductor 40 as L = 0.196 nH, R = 18
9.6mΩ, the capacitance of the second conductor 50 is C = 281.2pF
Are shown, and it can be understood that the LC noise filter of the embodiment shows good attenuation characteristics over a wide band as shown in FIG.

In the present invention, the value of the inductance L1 can be arbitrarily set by increasing or decreasing the number of the folded portions 22 and increasing or decreasing the number of turns of the first conductor 40. Also, by increasing or decreasing the number of turns of the second conductor 50 with respect to the first conductor 40, or by changing the width of each conductor in various ways in the folding order, the value of C can be set arbitrarily. it can. Therefore, a three-terminal LC noise filter having arbitrary L1 and C can be easily designed and manufactured.

In addition, when it is desired to increase L1 of the first conductor 40, it is effective to attach a magnetic material to the surface of each conductor 40 or 50 by various methods. The body can be mixed. In addition, as shown by a dotted line in FIG.
A magnetic core insertion hole 310 is formed at the center of 300, and the surface of the laminate 300 is powder-coated with a magnetic material, or is housed in a magnetic material container, so that the periphery of the laminate 300 is inserted through the insertion hole 310. A passing magnetic path may be formed.

When it is desired to increase the capacitance C of the LC noise filter, the conductors 40, 5 shown in FIGS.
The conductor width d of 0 may be formed to have an arbitrary width. By forming the capacitor conductor width d to be somewhat wider by the inductor conductor, the conductor 50 is
As a shield conductor, and a short circuit between lines can be prevented more effectively.

Second Embodiment FIG. 7 shows a second preferred embodiment of the present invention.

In the LC noise filter of the embodiment, the first conductor 40 and the conductor 50 are formed as a repetition of the same pattern.
In this embodiment, as shown in FIG. 7, the coil pattern is formed so as to gradually become smaller.

Accordingly, when the first insulating sheet 20 is folded in a zigzag shape, the first conductor 40 and the conductor 50 are wound so that the coil diameter becomes gradually smaller.

FIG. 8 shows the attenuation characteristics of the three-terminal LC noise filter according to the present embodiment.
= 149.5 nH, R = 311.5 mΩ, and data when the conductor 50 is set to C = 105.8 pF. It will be understood that the attenuation characteristics of this embodiment exhibit excellent attenuation characteristics over a wide band, although the attenuation pattern is slightly different from that of the above embodiment.

Third Embodiment FIGS. 9 and 10 show a third preferred embodiment of the present invention. Members corresponding to those in the first and second embodiments are denoted by the same reference numerals, and description thereof is omitted.

FIG. 9 (A) shows a state on the front surface 20a side of the first insulating sheet 20, and FIG. 9 (B) shows a state on the back surface 20b side. The insulating sheet 20 of the embodiment is provided with extension regions 26 and 28 on both sides in the width direction. Then, as shown in FIG. 2A, the first conductor 40 has input / output terminals 44a and 44b at both ends of the first conductor 40 formed on the extended region 28 so as to be widely covered. In addition, as shown in FIG.
The ground terminal 52 is formed so as to cover a wide area on the extension region 26.

Then, from the insulating sheet 20, the terminals 44a, 44b,
Except for the area where 52 is formed, the extended areas 26 and 28 are cut and removed.

Then, the insulating sheet 20 thus formed is
As shown in FIG. 10 (A), folding is performed in the same manner as in the above embodiment, and a laminate 300 as shown in FIG. 10 (B) is formed. At this time, it is preferable to bond between the folded portions 22 using an insulating adhesive or the like.

Then, the wide terminals 44a, 44b and 52 projecting outward from the laminate 300 shown in FIG. 10 (B) are sequentially folded in the direction of the arrow in the figure, and the state shown in FIG. The LC noise filter shown in FIG. At this time, each folded terminal 44a,
44b and 52 are preferably bonded and fixed to the laminated body using an insulating adhesive or the like.

By doing so, according to the present embodiment, the thin flat SMD (surface mount device) type L
It is possible to obtain a C noise filter, which is extremely suitable for performing circuit assembly that has recently become increasingly automated.

Note that the LC noise filter of the embodiment has the terminals 44a, 44b,
52 can also be directly soldered and fixed to a circuit board or the like. If necessary, pins may be attached to these terminals for use.

In this embodiment, the input / output terminals 44a, 44a of the first conductor 40 are used.
The case where b and the ground terminal 52 of the second conductor 50 are located in the opposite direction of the stacked body 300 has been described as an example. However, the present invention is not limited to this, and it is also possible to form the ground terminal 52 between the input / output terminals 44a and 44b.

In this case, the front surface 20a and the back surface 20b of the insulating sheet 20
The first conductor has a pattern shown in FIGS. 11 (A) and 11 (B).
40 and the second conductor 50 are formed by coating, and are sequentially folded as shown in FIGS.
May be formed.

Fourth Embodiment FIG. 13 shows a fourth preferred embodiment of the present invention. Members corresponding to those of the above-described embodiments are denoted by the same reference numerals, and description thereof is omitted.

The LC noise filter of the present embodiment is a normal mode type LC noise filter as in the above embodiments.

The feature of this embodiment is that the second conductor 50 functioning as a capacitor conductor is divided into a plurality of parts, and each divided section is grounded to form divided ground conductors 50-1, 50-2, 50-3, 50-4. It is in. Then, each divided ground conductor 50-1, 50-2, 50-3, 50-4
Are connected to the grounding pins 54a-1, 54a-2, 54a, respectively.
-3, 54a-4 are attached and fixed in the same manner as in the first embodiment.

When the insulating sheets 20 and 30 covered with the first and second conductors 40 and 50 are bent as shown in FIGS. 13 (B) and 13 (C) to form a laminate, these grounding pins are used. 54a−1,5
4a-2... 54a-4 are put together to form one ground pin 54 finally.

In the LC noise filter formed in this way, since the self-inductance L of each of the divided ground conductors 50-1, 50-2,. The obtained capacitance can be used as it is as a capacitor of the LC noise filter.

The present inventor further studied and found that the position of the divided ground conductors 50-1, 50-2,..., 50-4 facing the first conductor 40 functioning as an inductor was determined by the attenuation of the noise filter. They have been found to have a significant effect on properties. Then, as in this embodiment, the divided ground conductors 50-1, 50
It was confirmed that excellent attenuation characteristics could be obtained by arranging -4 at a position closer to the input / output terminal of the first conductor 40 in terms of an electric circuit.

Also, how to form the ground pins 54a-1, 54a-2... 54a-4 of the divided ground conductors 50-1, 50-2. As a result, one input / output pin 46a
Divided ground conductor 50-1, which is located in an electrical circuit
50-2, it is preferable that the ground pins 54a-1, 54a-2 are located closer to the input / output pin 46a in terms of the electric circuit, and the other divided ground conductors 50-3, 50-4 are each other. Ground pins 54a-3, 54a located close to the input / output terminal 46b in terms of electric circuit
It was confirmed that it was preferable to arrange -4.

By doing so, the LC noise filter of the present embodiment functions as a normal mode filter having good attenuation characteristics.

Fifth Embodiment FIG. 14 shows a fifth preferred embodiment of the present invention.

The LC noise filter of each of the above embodiments has a single sheet-like shape as the first insulating sheet 20 (when the second insulating sheet 30 is used, the first and second insulating sheets 20 and 30). Was used. That is, taking the first insulating sheet 20 as an example, the respective folding regions 20-1, 20-2,.
No. 20-8 was formed as one continuous sheet via a bent portion provided with a perforation.

On the other hand, according to the present invention, each of the folded portions 22-1, 22-
2 to 22-8 are separately formed as shown in FIG.

That is, in the present embodiment, the first and second conductors 40, 50
A conductor punched and formed into a predetermined pattern shape is used. Then, the first conductor 40 thus formed is connected to each of the folded regions 22-1, 22- of the first insulating sheet 20.
2. Adhere and fix to 22-8. Further, the second conductor 50
, The respective folding regions 32-1, 32-2,... Of the second insulating sheet 30.
Attach and fix to 32-8.

As a result, each of the folded portions 22-1 and 22-1,
22-8 are connected to each other by a first conductor 40, and furthermore, each of the folded portions 32-1 and 32-
.. 32-8 are interconnected by a second conductor 50.

Therefore, the first and second insulating sheets 20 and 30 thus formed are alternately and zigzag folded in the opposite direction as in the first embodiment to form a laminate. An LC noise filter similar to that of the first embodiment can be formed.

In this embodiment, the first and second conductors 40, 5
0 is coated with an insulating film, and the first and second conductors 40 and 50 are connected to the folded portions 22-1, 22-2,.
Is preferably formed so as not to be short-circuited in the gap between them.

Sixth Embodiment FIGS. 15 and 16 show a preferred sixth embodiment of the present invention.

The LC noise filter of each of the above embodiments is a normal mode noise filter, but the feature of this embodiment is that a common mode LC noise filter is formed.

That is, in the LC noise filter of this embodiment, as shown in FIG. 15, input / output terminals 52a and 52b are provided not only at both ends of the first conductor 40 but also at both ends of the second conductor 50. It is characterized in that input / output pins 54a, 54b are connected to 52a, 52b.

FIG. 16 shows an equivalent circuit diagram of the LC noise filter of the present embodiment. As shown in FIG. 16, the first and second conductors 40 and 50 of the embodiment are respectively composed of inductors L1 and L2. It functions as a conductor, and a capacitance C is formed between these two conductors 40 and 50 in a distributed constant manner.

As a result, the LC noise filter according to the present embodiment functions as a four-terminal common mode type LC noise filter having good attenuation characteristics.

Seventh Embodiment FIGS. 17 to 19 show a preferred seventh embodiment of the present invention. Members corresponding to those in the first to fifth embodiments are denoted by the same reference numerals, and description thereof is omitted.

The LC noise filter of each of the above embodiments is formed as a common mode type filter, similarly to the sixth embodiment.

As shown in FIG. 17, the LC noise filter of the embodiment has a first insulating sheet 20 and a second insulating sheet 30 having the same structure.
Prepare Then, the surface 20a of the first insulating sheet 20
Then, the first conductor 40 is coated and formed in the same manner as
The third conductor 60 having the same pattern as the first conductor 40 is also formed on the surface 30a of the insulator sheet 30.

Then, the second conductor 50 functioning as a capacitor conductor is sandwiched between the two insulating sheets 20 and 30 in a sandwich shape, and the two are adhered to each other.

Then, the first and second sheets 20 and 30 thus bonded are folded in a zigzag manner in the same manner as in each of the above-described embodiments, to form a laminate 300 shown in FIG. At this time, the input / output pins 46a, 66a, 54, 46b, 66b are arranged at equal intervals and in a straight line (inline) so that the terminals 44a, 44b, 64a, 64a of the inductor conductors 40, 60 and the capacitor conductor 50 are arranged.
4b and 52 are preferably formed. And this laminate 3
00 is molded around its periphery using an epoxy resin or the like.

FIG. 19 shows an equivalent circuit diagram of the common mode type LC noise filter thus formed. As shown in the figure, the first and third conductors 40 and 60 of the embodiment function as L1 and L2 inductor conductors, respectively, and between these two inductor conductors 40 and 60 and the second conductor 50. The capacitance C is formed in a distributed manner.

Thus, the LC noise filter of the present embodiment functions as a common mode LC noise filter having good attenuation characteristics.

Other Embodiments Note that the present invention is not limited to the above-described embodiments, and various modifications can be made.

For example, in each of the above embodiments, the case where an insulating layer is coated on the surface of each conductor functioning as an inductor conductor has been described as an example, but the present invention is not limited to this.
As shown in the figure, insulating sheets 70 and 80 may be laminated on the insulating sheets 20 and 30 so as to cover the inductor conductors 40 and 60, respectively. In this case, the insulating sheets 70, 80, 20, 3
It is preferable that 0 has the same structure.

In each of the above embodiments, the ring-shaped inductor conductors 42 and the capacitor conductors 56, which are partially notched, are formed alternately and continuously in the opposite direction on the surface of the continuous folded portion 22. However, the present invention is not limited to this, and may be formed, for example, as shown in FIG.

That is, a ring-shaped inductor conductor 22 partially cut out is provided in the upper half of the folded portion 22 of the first insulating sheet 20 continuously in the same direction in the same pattern, and is continuously provided in the lower half thereof. Similarly, the conductors 22 for inductors having the pattern turned upside down are continuously provided in the same pattern and the same direction. Then, the conductor 22 for an inductor provided in this manner is formed over a plurality of turns.

After that, the first insulating sheet 20 is folded in a zigzag manner as in the above embodiment, so that an LC noise filter having a large number of turns of the first conductor 40 and a large inductance L1 can be obtained.

In this case, one end of the inductor conductor 40 is
Since the conductor 22 is located at a position surrounded by the conductor 22, the inner end and the input / output terminal 44 are connected by the jumper wire 23.

Thus, the first conductors 40, 40 in the pattern shown in FIG.
By forming the second conductor 50 (not shown), relatively large L and C can be obtained even when the number of the folded portions 22 of the insulating sheet 20 is small.

In the present invention, the performance in the high frequency band can be further improved by using an electromagnetic wave absorbing and heating element as the material of the insulating sheet.

Further, in each of the above embodiments, the case where each conductor is formed so as to face each other via the insulating sheet has been described as an example. However, even if these conductors do not completely face each other, the capacitance between them is not limited. If formed as a distributed constant,
There may be a deviation between the opposing positions.

[Effects of the Invention] As described above, according to the present invention, the first conductor is formed on one side of each folded portion of the insulating sheet,
A second conductor is formed on the other surface so as to face the first conductor, and the insulating sheets are folded alternately and in a zigzag shape in the opposite direction to be laminated, so that the first conductor has a predetermined shape. By adopting a novel configuration in which the second conductor functions as a coil having the number of turns and forms a capacitance between the second conductor and the first conductor, ringing or the like does not occur and noise that enters is reliably prevented. A small and inexpensive LC noise filter that can be easily removed can be obtained.

In particular, according to the present invention, it is presumed that the capacitance is formed in a distributed constant manner between the first and second conductors, thereby reducing various noises as compared with the conventional lumped constant noise filter. It is possible to obtain an LC noise filter having excellent attenuation characteristics that can reliably remove attenuation.

[Brief description of the drawings]

1 to 6 show a three-terminal normal mode type LC according to the present invention.
FIG. 1 is an explanatory view of a preferred example when applied to a noise filter. FIG. 1 is an explanatory view of a series of manufacturing steps, and FIG. 1 (A) shows a case where a plurality of folds are continuously formed via a fold. FIG. 3B is an explanatory view of the case of laminating, FIG. 2B is an external perspective view of the laminated body formed by folding, and FIG. 2C is a final noise formed by molding the laminated body of FIG. FIG. 2 is an explanatory view of the appearance of the filter, FIG. 2 is an explanatory view in the case of forming a conductor and a capacitor conductor on both sides of an insulating sheet, and FIG. 3 is a pattern explanatory view of each of the inductor conductor and the capacitor conductor. (A) is an explanatory view of the insulating sheet shown in FIG. 2 as seen from the direction of arrow 100, FIG. 2 (B) is an explanatory view of the insulating sheet shown in FIG. 2 as seen from the direction of arrow 200, and FIG. FIG. 5 is an equivalent circuit diagram of the LC noise filter according to the embodiment, and FIG. FIG. 6 is an explanatory view showing the appearance of a noise filter formed by press forming so that the filter is located on a straight line when the filter is displaced in the thickness direction. FIG. 6 is an attenuation characteristic of the LC noise filter according to the present embodiment. FIGS. 7 and 8 are explanatory views of a preferred second embodiment in which the present invention is applied to a three-terminal LC noise filter. FIGS. 7 (A) and (B) show insulation. It is explanatory drawing in the conductor pattern formed in both surfaces of a sheet | seat, FIG. (A) is a pattern explanatory drawing of the inductor conductor formed by coating on the front side of the insulating sheet, and FIG. FIG. 8 is an explanatory diagram showing the attenuation characteristics of the LC noise filter of the present embodiment, and FIGS. 9 and 10 are explanatory diagrams showing a third preferred embodiment of the present invention. Fig. 9 shows the shape on both sides of the insulation sheet. (A) is an explanatory view of a pattern of an inductor conductor formed on the front side of the insulating sheet, and FIG. (B) is a capacitor formed on the back side of the insulating sheet. FIGS. 10 (A) to 10 (D) are explanatory views of a series of assembling steps of an LC noise filter of the present embodiment, and FIGS. 11 and 12 are diagrams of a modification of the third embodiment. 11 (A) and 11 (B) are explanatory diagrams of conductor patterns formed on both surfaces of an insulating sheet, and FIG. 11 (A) is an inductor conductor formed on the surface side of the insulating sheet. 13 (B) is a pattern explanatory view of a capacitor conductor formed on the back side of the insulating sheet, FIGS. 12 (A) to 12 (D) are explanatory views showing the assembling process, and FIG. (A) to (C) are explanatory views of a preferred fourth embodiment of the present invention. FIG. 4 is an explanatory view of a preferred fifth embodiment of the present invention, FIGS. 15 and 16 are explanatory views of a preferred sixth embodiment of the present invention, and FIGS. FIG. 17 is an explanatory view of a preferred seventh embodiment of the present invention. FIG. 17 is an explanatory view of covering an inductor sheet and a capacitor conductor on an insulating sheet, and FIG. 18 is formed by folding the insulating sheet in a zigzag shape. 19 is an equivalent circuit diagram of this embodiment, FIGS. 20 and 21 are explanatory diagrams of another embodiment of the present invention, and FIG. 22 is a conventional LC noise filter. FIG.
(A) is an explanatory diagram of a specific configuration, and (B) is an equivalent circuit diagram thereof. 20 first insulating sheet, 22 folded part, 24 bent part, 30 second insulating sheet, 40 first inductor conductor, 42 conductor for inductor, 44a, 44b I / O terminal, 46a, 46b I / O pin, 50 Capacitor conductor, 52 Ground terminal, 54 Ground pin, 56 Conductor for capacitor, 60 Inductor Conductor, 62: Conductor for inductor, 64a, 64b: Input / output terminal, 66a, 66b: Input / output pin.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-58-141513 (JP, A) JP-A-62-233911 (JP, A) JP-A-62-183616 (JP, A) JP-A-59-141 22304 (JP, A) JP-A-60-68708 (JP, A) JP-A-63-313906 (JP, A) JP-A-56-114574 (JP, U)

Claims (19)

(57) [Claims] 1. An insulating sheet having a plurality of folds that are alternately folded and stacked in opposite directions, and an interlayer when each fold is alternately folded and stacked on one side of each of the folds. A first conductor provided to form a coil having a predetermined number of turns in an insulated state; and a first conductor provided on the other surface side of each of the folds so as to substantially face the first conductor. And a second conductor forming a capacitance between the first and second conductors, wherein the first and second conductors are formed to face each other with a given conductor width. filter. 2. An insulating sheet having a plurality of folds that are alternately folded and stacked in opposite directions, and an interlayer when each fold is alternately folded and stacked on one side of each of the folds. A first conductor provided to form a coil having a predetermined number of turns in an insulated state; and a first conductor provided on the other surface side of each of the folds so as to substantially face the first conductor. And a second conductor that forms a capacitance between the first and second conductors, wherein the first and second conductors are opposed to each other so as to sandwich the second conductor between first conductors located on both sides thereof. An LC noise filter characterized by the following. 3. An insulating sheet having a plurality of folds that are alternately folded and stacked in opposite directions, and an interlayer when each fold is alternately folded and stacked on one side of each of the folds. A first conductor provided to form a coil having a predetermined number of turns in an insulated state; and a first conductor provided on the other surface side of each of the folds so as to substantially face the first conductor. And a second conductor forming a capacitance between the first and second conductors, wherein the first and second conductors are formed to face each other with a given conductor width, and the first and second conductors are formed opposite to each other. Wherein the first conductor is opposed to the second conductor so as to sandwich the second conductor between the first conductors located on both sides of the second conductor. 4. The insulating sheet according to claim 1, wherein the insulating sheet is overlapped with the insulating sheet so that the first conductor is sandwiched between the insulating sheet and the insulating sheet. An LC noise filter comprising: the first conductor insulating sheet having a folded portion; wherein the layers of the laminated first conductor are insulated from each other. 5. The first conductor according to claim 1, wherein an insulating layer is formed on the surface of the first conductor, and each layer of the laminated first conductor is insulated. LC noise filter. 6. The LC noise filter according to claim 1, wherein the second conductor is formed wider than the first conductor. 7. The insulation sheet according to claim 1, wherein the insulation sheet is overlapped with the insulation sheet so as to sandwich the second conductor between the insulation sheet and the insulation sheet. LC including the second conductor insulating sheet having a folded portion
Noise filter. 8. The first conductor according to claim 1, wherein the first conductor is formed as an inductor conductor having input / output terminals at both ends thereof, and the second conductor is provided with a ground terminal. An LC noise filter formed as a capacitor conductor and used as a normal mode type filter. 9. The LC noise filter according to claim 8, wherein the second conductor is divided into a plurality of sections, and each section is connected to a ground terminal. 10. The filter according to claim 1, wherein the first and second conductors are formed as inductor conductors having input / output terminals provided at both ends thereof, and used as a common mode filter. LC noise filter characterized by the following. 11. The method according to claim 7, wherein one side of each of the folded portions of the second conductor insulating sheet is
A third conductor provided so as to be substantially opposed to the second conductor via the fold portion, wherein the third conductor is formed such that when the fold portions are alternately folded in the opposite direction and laminated, the respective layers are separated from each other. The second conductor is formed as a capacitor conductor provided with a ground terminal, and the first and third conductors are provided at both ends thereof. An LC noise filter formed as an inductor conductor provided with an output terminal and used as a common mode filter. 12. The insulating sheet for a second conductor according to claim 11, wherein the third insulating sheet is overlapped with the insulating sheet for a second conductor so as to sandwich the third conductor between the second insulating sheet and the insulating sheet for the second conductor. An LC noise filter comprising: the third conductor insulating sheet having a folded portion that is folded and stacked in a direction. 13. The external connection conductor according to claim 1, wherein each of the terminals provided on the folded portion is provided with an external connection conductor projecting outside when the folded portions are folded and stacked. LC noise filter. 14. The LC noise filter according to claim 1, wherein each of the insulating sheets is formed as one sheet in which each folded portion is continuous through a bent portion. 15. The LC noise filter according to claim 14, wherein a perforation is provided in the bent portion. 16. The LC noise filter according to claim 15, wherein a part of each conductor is provided along the perforation. 17. The folding sheet according to claim 1, wherein each of the insulating sheets is formed such that each of the folding sections is formed separately, and each of the folding sections is interconnected by each of the conductors provided between the folding sections. LC noise filter characterized by being performed. 18. The inductor according to claim 1, wherein the first conductor comprises a ring-shaped inductor conductor partially cut away on one side of each of the folds arranged continuously. An LC noise filter which is provided alternately and continuously in the opposite direction, and forms a predetermined number of turns when the folded portions are folded and stacked. 19. The LC noise filter according to claim 1, wherein each of the conductors is formed such that a conductive pattern thereof is gradually reduced.