KR0143905B1 - Lc noise filter - Google Patents

Abstract

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Description

LC Noise Filter

1A to 1C are explanatory views showing one example of a substrate used in the LC noise filter of the present invention;

2A to 2C are explanatory diagrams of a normal mode LC noise filter of this embodiment formed by providing a conductor in a groove of FIGS. 1A to 1C;

3A and 3B are equivalent circuit diagrams of the first and second embodiments, respectively;

4 is an explanatory diagram of an inductor conductor that faces away from each other with a wall interposed therebetween;

5A to 5C are explanatory diagrams of a common mode LC noise filter to which the present invention is applied;

6 is an equivalent circuit diagram of a third embodiment;

FIG. 7 is an explanatory view showing an example of a deep groove LC noise filter, FIG. 7A is a plan explanatory view of the LC noise filter, FIG. 7B is a sectional view taken along the line A-A of FIG. 7A, and FIG. 7C is a rear view of FIG.

8 is an explanatory diagram of a main part of the LC noise filter of FIG. 7A;

FIG. 9 is an explanatory diagram showing an example in the case where the spiral groove formed on the substrate shown in FIG. 8 is tapered; FIG.

10 and 11 are explanatory views showing a modification of the deep groove LC noise filter;

Fig. 12 shows an embodiment in which a waste gas is formed around the filter, and Fig. 12A is an explanatory view of an LC noise filter in which waste gas is formed using a housing. Explanatory drawing of LC noise filter which formed

Fig. 13 is an explanatory diagram in a case where a multi-channel noise filter is formed by stacking PC boards and using one of the noise filters according to any of the above embodiments;

14 is an explanatory diagram in the case of forming both a signal line multi-channel noise filter and a power line noise filter on a PC board on which an IC is mounted;

Fig. 15 is an explanatory diagram in the case where a multichannel noise filter is formed on a vertically long insulating substrate and this is mounted on a PC board;

16 is an explanatory diagram showing an example in the case where the present invention is applied to a cylindrical filter;

17A and 17B are explanatory views showing one example of a conventional noise filter;

18 is an equivalent circuit diagram of a conventional noise filter shown in FIG.

* Explanation of symbols for main parts of the drawings

10: Dielectric substrate 12-1, 12-2, 12-3, 12-4: Spiral groove

20-1, 20-2: Inductor conductor 30-1, 30-2: Shielded conductor

The present invention relates to an improvement of an LC noise filter formed on a dielectric.

Conventionally, as shown in FIG. 17A, an inductor conductor 2 is formed in a spiral shape on one surface 10a of a dielectric substrate 10 such as ceramic, and grounded on the other surface 10b as shown in FIG. 17B. The noise filter which formed the conductor 4 is known.

As shown in Fig. 18, the noise filter has a constant inductance between the spiral inductor conductor 2 and the ground conductor 4 while the spiral inductor conductor 2 obtains the inductance L. Capacitor C is obtained and functions as an LC noise filter.

However, the conventional LC noise filter described above has the following problems.

[a] the first problem

In the conventional noise filter, an eddy current is generated in the ground conductor 4 provided on the rear surface side of the substrate 10. For this reason, the inductance as expected in the inductor conductor 2 formed in the spiral shape is not obtained, and there is a problem that only an electrical characteristic similar to a capacitor can be obtained rather than an LC noise filter.

In other words, in the LC noise filter, the ground conductor 4 is capacitively coupled to the spiral inductor conductor 2 by capacitive and inductive coupling. Therefore, electromotive force is generated on the ground conductor 4 by the magnetic flux generated by the energizing current of the spiral inductor conductor 2, and a short circuit current as shown by the solid line A flows due to the electromotive force.

Since the spiral inductor conductor 2 acts on the primary coil in the transformer, for example, the ground conductor 4 acts like a shorted secondary coil, There was a problem that the inductance L was not obtained and the LC noise filter could not be sufficiently functioned.

[b] the second problem

This noise filter applies a signal to both electrodes 6 and 8 of the inductor conductor 2 and removes the noise contained in the signal. However, when the frequency of the energized signal increases, the inductor conductor wound in a spiral shape ( There was a problem that a line short circuit, as indicated by arrow B in 2), occurred and the function of the inductor conductor 2 as an inductor was deteriorated.

In particular, such a short circuit phenomenon occurs frequently as the frequency of the energized signal increases, so that the conventional noise filter is difficult to use as a high frequency noise filter.

SUMMARY OF THE INVENTION An object of the present invention has been made in view of such a conventional problem, and an object of the present invention is to provide an LC noise filter having excellent electrical characteristics that solves the above-mentioned problems.

The above and other objects and novel features of the present invention will become apparent from the description and the accompanying drawings.

An outline of typical ones of the inventions disclosed in the present application will be briefly described as follows.

That is, the LC noise filter of the present invention includes a dielectric, a plurality of helical grooves formed so as to be adjacent to at least one side of the dielectric, and a plurality of inductor conductors formed in each of the grooves, and each inductor conductor is formed through a wall of the dielectric. A capacitor is formed between the inductor conductors in contact with each other.

Hereinafter, the operation of the present invention will be described.

The present inventors examined, for example, why inductors as much as expected are not obtained in the inductor conductor 2 formed in a spiral shape in the LC noise filter shown in FIG.

The ground conductor 4 was formed in the shape of a comb that is hard to flow in the short circuit current in accordance with the assumption that the main cause thereof is a short circuit current flowing in the ground conductor 4 as indicated by the solid line A. A noise filter was formed.

However, even in this case, the inductor conductor 2 cannot obtain the inductance as expected and an LC noise filter with sufficient electrical characteristics cannot be produced.

Based on this fact, how can a conductor functioning as a capacitor be formed on an inductor conductor formed in a spiral shape on one side of the dielectric to obtain an LC noise filter with good characteristics without degrading the function of the inductor conductor? The review was promoted.

The inventors of the present invention can obtain an LC noise filter having good electrical characteristics without reducing the inductance of the inductor conductor by forming the other conductor so as not to disturb the magnetic path of the magnetic flux generated when the spiral inductor conductor is energized. It is assumed that there is not. A plurality of helical grooves were formed adjacent to each other on at least one side of the dielectric, and an inductor conductor was formed in each groove to form an LC noise filter.

As a result, the inductor conductor provided in each groove forms a cacher therebetween facing the inductor conductor adjacent to each other with the wall surface between the spiral grooves interposed therebetween. Therefore, the optimum capacitance can be obtained by appropriately selecting the material of the dielectric.

In addition to this, since there is no conductor on the dielectric that interferes with the magnetic path of each inductor conductor, sufficient inductance is obtained for each inductor conductor.

Thereby, according to this invention, the LC noise filter which has the outstanding electrical characteristic can be obtained.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

In addition, in all the figures for demonstrating an Example, the same code | symbol is attached | subjected to the thing which has the same function, and the repeated description is abbreviate | omitted.

[First Embodiment]

First, a preferred embodiment in the case where the LC noise filter according to the present invention is formed as a normal mode LC noise filter will be described.

As shown in Fig. 1A, the LC noise filter of this embodiment is provided with two spiral grooves 12-1 and 12-2 adjacent to the surface 10a of the dielectric substrate 10 such as ceramics. The back surface 10b is provided with the groove 14-1 extending from the center to the circumference as shown in FIG. 1C. The inner end portions of the helical grooves 12-1 and the grooves 14-1 at the center of the substrate 10 communicate with each other via through holes 16-1, as shown in Fig. 1B. It is.

As shown in FIG. 2A, each of the spiral grooves 12-1 and 12-2 provided on the surface 10a side of the substrate 10 includes first and second inductor conductors 20-1, ( 20-2 is provided, and the outer ends of the inductor conductors 20-1 and 20-2 are connected to the terminals 22-1 and 22-2.

Also, as shown in Fig. 2C, a lead 26-1 is provided in the groove 14-1 provided on the rear surface side of the substrate 10, and the outer end thereof is connected to the terminal 28-1. As shown in Fig. 2B, the inner end is electrically connected to the inner end of the first inductor conductor 20-1 via the through hole 16-1.

Each of the conductors 20-1, 20-2, and 26-1 is formed in advance in portions other than the grooves 12-1, 12-2, and 14-1 of the substrate 10. Can be easily formed by dipping into a conductive tank filled with a liquid conductor.

Also, even when the substrate 10 is immersed without applying a resist on the surface, the substrate surface is then polished to remove the conductors attached to the grooves 12-1, 12-2, and 14-1. It can also be easily formed by using.

In addition to the immersion, a conductor can be formed in each groove by, for example, plating a dielectric.

3A shows an equivalent circuit diagram of the LC noise filter of this embodiment. In this embodiment, the first inductor conductor 20-1 connected to the terminals 22-1 and 28-1 is a first inductor. The second inductor 20-2, which functions as L1 and is connected to the ground terminal 22-2, functions as a second inductor L2.

In addition, the first and second inductor conductors 20-1 and 20-2 have wall surfaces 18 located between the grooves 12-1 and 12-2 as shown in FIG. Opposite to each other in between. For this reason, both of them are capacitively coupled to each other by capacitance, and capacitor C is distributedly formed between them. Therefore, by using a material having a high dielectric constant as the substrate 10, the value of the capacitor C can be set to a large value as necessary.

As a result, the noise filter of the present embodiment functions as a distribution constant LC noise filter having a circuit configuration as shown in Fig. 3A.

In particular, in this noise filter, the second inductor conductor 20-2, which forms a capacitor between the first inductor conductor 20-1, is formed so as not to disturb the magnetic path of the first inductor conductor 20-1. .

That is, the magnetic flux generated when the first inductor conductor 20-1 is energized is the rear surface of the substrate 10 in the wall surface 18 located between the grooves 12-1 and 12-2. Pass to the side and in the reverse direction. At this time, if the conductor 20-2 is provided so as to obstruct the magnetic path (for example, if the conductor 20-2 is provided so as to cover the surface of the wall surface 18), then the conductor 20-2 can be used. It is blocked by the 1st inductor conductor 20-1, and it cannot fully function as an inductor.

On the other hand, by providing the second inductor conductor 20-2 so as to be adjacent to the first inductor conductor 20-1 as in the present invention, the second inductor of the first inductor conductor 20-1 is a second inductor. Since no interference is caused by the conductor 20-2, the effect as an LC noise filter can be sufficiently exhibited without lowering the inductance of the vortex-shaped first inductor conductor 20-1.

In addition to this, according to this embodiment, since the second inductor conductor 20-2 to be used as the ground conductor is formed between the lines of the first inductor conductor 20-1 to be used as the conducting conductor, The second inductor conductor 20-2 functions as a shield (shield) conductor with respect to the first inductor conductor 20-1.

Therefore, the noise filter of this embodiment solves not only the first problem but also the second problem, and functions as a normal mode noise filter having excellent electrical characteristics from the low frequency band to the high frequency band.

In the present invention, since the conductors 20-1 and 20-2 are provided in the spiral grooves 12-1 and 12-2, the conductors are coated on the surface of the substrate 10. On the other hand, the cross-sectional shape and cross-sectional area of each conductor can be arbitrarily formed. For example, by taking a large cross-sectional area, it becomes very suitable as a garden LC noise filter with a relatively large current carrying current.

Second Embodiment

Next, a preferred embodiment in the case where the present invention is applied to a common mode noise filter will be described.

The characteristic of the present embodiment is that the groove 14-2 is provided on the back surface 10b side of the substrate 10 shown in Figs. 1 and 2 as indicated by the dashed-dotted line in the figure, and this groove 14-2 is provided. ) Is a lead 26-2 electrically connected through the inner end of the second inductor conductor 20-2 and the through hole 16-2.

In addition, since the other structure is the same as that of the said 1st Example, the same code | symbol is attached | subjected to the corresponding member and the description is abbreviate | omitted.

3B shows an equivalent circuit diagram of the LC noise filter of this embodiment. In this embodiment, both ends of the first inductor conductor 20-1 and the second inductor conductor 20-2 are connected to the input / output terminals 22-1, 28-1, and 22-2, and 28-28. 2), so that the LC noise filter of this embodiment functions as a four-terminal LC noise filter of the common mode type.

Third Embodiment

Next, a preferred embodiment of an LC noise filter using a shielded conductor will be described.

5A shows a preferred example of the LC noise filter of this embodiment. In the noise filter of this embodiment, the first and second inductor conductors 20-1 and 20-2 are provided on the surface 10a side of the substrate 10 as in the first embodiment. In addition, as shown in FIG. 5C, the first lead 26-1 and the second lead 26-2 are provided on the back surface 10b side of the substrate 10. The inner ends of the first inductor conductor 20-1 and the first lead 26-1 are electrically connected to each other via the through hole 16-1, as shown in FIG. 5B. The inner ends of the conductors 20-2 and the second leads 26-2 are also electrically connected through the through holes 16-2.

As a result, the noise filter of this embodiment functions as a four-terminal LC noise filter of the common mode type.

However, in the common mode noise filter, since both of the first and second inductor conductors 20-1 and 20-2 are used as conductors for conduction, when the energization frequency increases, line short circuit occurs between them. There is concern.

The present embodiment is characterized in that the first shielding conductor (30-1) is formed in a spiral between the inductor conductor (20-1) and (20-2) in order to more effectively prevent the above line short circuit phenomenon. At the same time, the second shielding conductor 30-2 is spirally formed between the inductor conductors 20-1 and 20-2.

The shielding conductors 30-1 and 30-2 may be formed on the surface 10a of the substrate 10, but in this embodiment, similar to the inductor conductors 20-1 and 20-2. It is provided in the spiral grooves 12-3 and 12-4. On the rear side of the substrate 10, a ground lead 26-3 having a ground terminal 28-3 is provided at an outer end thereof, and an inner end of the ground lead 26-3 is provided with the first and second ends. The inner ends of the second shielding conductors 30-1 and 30-2 are electrically connected to each other via through holes not shown.

As a result, the LC noise filter of this embodiment functions as a common mode four-terminal LC noise filter of the equivalent circuit as shown in FIG. In this case, the shielding conductors 30-1 and 30-2 can effectively prevent the line short between the inductor conductors 20-1 and 20-2. In addition, the second problem is solved to function as a noise filter having excellent electrical characteristics from the low frequency band to the high frequency band.

Fourth Embodiment

In addition, in each said embodiment, each groove formed in the board | substrate 10 may be formed in arbitrary depth as needed.

Fig. 7A shows a preferred example in which the LC noise filter of the first embodiment is formed in the same groove shape. The LC noise filter of this embodiment forms the substrate 10 in a thick shape, and the substrate 10 is formed. The two helical grooves 12-1 and 12-2 adjacent to each other on the surface side are formed in the same groove shape. In the spiral grooves 12-1 and 12-2, the first and second inductor conductors 20-1 and 20-2 are formed in the same manner as in the above embodiment. The outer ends of these inductor conductors 20-1 and 20-2 are connected to terminals 22-1 and 22-2.

In addition, as shown in FIG. 7C, a lead 26 is provided in the groove 14-1 provided on the rear surface side of the substrate 10. The outer end of the lead 26 is connected to the terminal 28-1, and the inner end thereof is inside the first inductor conductor 20-1 via the through hole 16-1 as shown in Fig. 7B. It is connected to the end. 7B is a sectional view taken along the line A-A in FIG. 7A.

As described above, the LC noise filter of this embodiment is formed into a deep groove shape in which each of the spiral grooves 12-1 and 12-2 has a sufficient depth. For this reason, the 1st and 2nd inductor conductors 20-1 and 20-2 are comprised like the spiral wound of two strip | belt-shaped conductors laminated | stacked through the dielectric. Accordingly, these first and second inductor conductors 20-1 and 20-2 form wall surfaces 18 positioned between the grooves 12-1 and 12-2 as shown in FIG. They face to face with each other, and sufficient capacitance is formed between them both.

In this way, according to this embodiment, a distributed constant noise filter having a larger capacitance than that in the first embodiment can be obtained.

In addition, in this embodiment, the spiral groove 12-2 provided with the ground spiral conductor 20-2 is somewhat deeper than the spiral groove 12-1 provided with the inductor conductor 20-1 for electricity supply. As a result, the spirally wound current-carrying inductor conductor 20-1 is well interposed between the layers by the grounding inductor conductor 20-2, whereby the line short circuit is more reliably prevented.

Incidentally, the LC noise filter of this embodiment is not formed in a plate shape as in the respective embodiments, but is formed in a so-called chip shape. Therefore, it becomes very suitable as a SMD (surface mounted device) type LC noise filter.

The spiral grooves 12-1 and 12-2 may be formed in a tapered shape open toward the outside as shown in Fig. 9 as necessary. In this way, even when the helical groove 12 is formed into a deep groove shape, the inductor conductor 20 can be reliably provided in each groove by immersing the substrate 10 in the conductive bath.

10 and 11 show a preferable example in the case where the deep groove-shaped spiral grooves 12-1 and 12-2 are provided so as to penetrate from the front side to the back side of the substrate 10. As shown in FIG.

In this case, since the groove is formed from the front side to the back side of the substrate 10, it is preferable to provide a presser plate for reinforcement on the front side or the back side thereof. In this embodiment, the pressing plate 11 is integrally formed on the rear surface side of the substrate 10, and the groove 14 continuous with the through hole 16 is formed on the surface thereof.

In addition, the LC noise filter of this embodiment attaches and fixes the electrode terminals 22-1, 22-2, and 28 to the substrate 10. FIG. This attachment may be performed, for example, using an adhesive or the like having sufficient resistance to solder heat.

Then, a resist is applied to portions other than the grooves of the substrate 10 in advance, and this is immersed in a conductive tank filled with a liquid conductor to form spiral conductors 12-1, 12-2 and leads. At this time, since the helical grooves 12-1 and 12-2 of this embodiment penetrate from the surface side of the substrate 10 to the back surface side, even if the grooves are deep, the conductors can be uniformly flowed into the inside thereof so that a good spiral The conductor can be formed.

Subsequently, an SMD type LC element can be obtained by mold (insulating covering may be performed) with insulating resin or the like.

Further, such a deep groove LC noise filter is not limited to the first embodiment, but can be widely applied to various LC filters of the present invention, for example, the LC noise filters of the second and third embodiments.

[Example 5]

In addition, in the LC noise filter of the present invention, the inductance L and the capacitance C of the noise filter can be arbitrarily set by appropriately selecting the material of the substrate 10 in addition to the number of windings and the arrangement of the inductor conductor 20.

For example, when the inductance L is to be large, the substrate 10 may be formed using a magnetic material or the like. In the case where the capacitance C is to be large, the substrate 10 may be a material having a high dielectric constant such as ceramics. It is good to form using or to adjust the depth of the groove | channel 12 and the thickness of the wall surface 18. FIG. In the case where both of these L and C are to be enlarged, the substrate 10 may be formed using both a material having a high dielectric constant and a magnetic material.

In addition, by stacking several noise filters and connecting each noise filter in series or in parallel with each other, a noise filter having an arbitrary L and C can be obtained. In particular, by connecting each stacked noise filter in series, one noise can be obtained. It can be used as an LC noise filter circuit having more inductance which cannot be obtained with a filter.

In addition, in the case where the inductance L is large, the noise filter formed as in the first to fourth embodiments may be housed in a housing forming a magnetic circuit.

Fig. 12A shows an example of the noise filter thus formed, which is characterized in that the noise filter 210 described in each of the above-described embodiments is housed in a housing 80 formed using a magnetic material.

In this case, the magnetic core through-hole 10c is formed in the substantially center part of the board | substrate 10, and the magnetic core 82 provided in the center part of the housing 80 is inserted through this through-hole 10c. By covering the cover 84 from the upper portion of the housing 80, a closed magnetic circuit dedicated to the noise filter is provided between the magnetic core 82, the housing 80 provided around the cover, and the cover 84. ).

By doing so, the noise filter of this embodiment is formed as an LC noise filter having a sufficiently large inductance.

In the present embodiment, the case where the closed path is formed by using the housing has been described as an example. However, the present invention is not limited to this, and the housing may be formed such that the magnetic circuit is closed as necessary.

12B shows an example of a noise filter in which the surface of the substrate 10 is powder-coated with a magnetic body.

In the noise filter of this embodiment, the magnetic core through-hole 10c is formed in the substantially center portion of the substrate 10, and the front and back surfaces of the substrate 10 are powder-coated using magnetic powder. As a result, the magnetic powder coating layer 86 forms a waste path exclusively for noise filter, and can significantly reduce the magnetic flux exposed to the outside.

As a result, the noise filter of the present embodiment, for example, is arranged to be adjacent to each other and used as a multi-channel noise filter, so that mutually adjacent noise filters rarely cause mutual interference such as ringing, resulting in excellent electrical characteristics. I can show it.

[Example of PC board]

As described in each of the above examples, the present invention can obtain a distributed constant LC noise filter having good electrical characteristics using the insulating substrate 10. For example, a PC board or the like can be used as the insulating substrate 10. Any number of distributed constant LC noise filters can be provided on this PC board without increasing the thickness of the board itself.

Therefore, by forming the distributed constant noise filter of the present invention on a PC board, it is very suitable as a noise filter for various electronic devices, which is required to be smaller and lighter in recent years, for example, to form a noise filter on a PC board. This makes it possible to significantly reduce the overall weight of the apparatus compared to using a conventional chip type noise filter. As the PC board, a film or sheet may be used, if necessary, in addition to the usual substrate.

Therefore, by using the distributed constant LC noise filter of the present invention in, for example, a laptop computer, it is possible to further promote the compact and light weight of the laptop computer.

In addition, even when the noise filter of the present invention is applied to an IC card PC board (consisting of a membrane board), etc., in which conventional noise filters cannot be mounted due to the required thickness constraint, any number of LC noise filters can be applied. It can be simply implemented.

Further, since the distribution constant LC noise filter of the present invention can be formed by simply printing and wiring on a PC board, it can be easily mounted on a PC board used for various purposes without increasing its thickness.

Fig. 13 shows a preferred embodiment in the case where a multi-channel noise filter for signal lines is formed on the PC board.

In this embodiment, several ICs 110 are mounted on the PC board 100, and several signal lines 112 are connected to these ICs 110. FIG.

Below the PC board 100, a PC board 200 provided with a multi-channel noise filter is stacked. The PC board 200 forms a plurality of LC noise filters 210 in any one of the above embodiments at positions corresponding to the input / output leads 112 of each IC 110. As a result, the multi-channel noise filter corresponding to the lead 112 of each IC 110 is formed in the PC board 200.

Such a multi-channel noise filter 210 can be simply formed on the PC board 200 by using a printing method, for example, and its size can be formed in a small space in accordance with the required L and C. have.

The PC board 200 thus formed is stacked on the PC board 100 and electrically connected to the respective leads 112 of the IC 110 positioned above the PC board 200.

As described above, according to the present embodiment, a multi-channel noise filter can be formed on the board 200 without increasing the thickness of the PC board 200, so that the electronic device itself can be miniaturized and light in weight.

In this embodiment, the case where the multi-channel noise filter 210 is formed on a board 200 different from the PC board 100 provided with the IC 110 or the like has been described as an example, but the present invention is not limited thereto. If there is room on the PC board 100 on which the IC 110 is mounted, the multi-channel noise filter 210 may be formed on the PC board 100.

In this embodiment, the case where the signal line multi-channel noise filter is formed on the PC board 200 has been described as an example, but in addition to this, a power line noise filter may be formed if necessary.

FIG. 14 shows an example in which the signal line multi-channel noise filter 210 and the power line noise filter 220 are formed on the PC board 100 on which the IC 110 is mounted. The PC board 100 is very suitable as a PC board for an IC card. The power line noise filter 220 may be formed as a multi-channel noise filter in accordance with the number of ICs 110 when there are several ICs 110.

In particular, it is preferable to use a common mode noise filter in a portable device that does not have a sufficient grounding box such as an IC card.

FIG. 15 shows an example in which a plurality of noise filters shown in the above embodiments are provided on the insulating substrate 10 formed in a rectangular shape and formed of a multi-channel noise filter 300.

The multi-channel noise filter 300 of this embodiment can be simply mounted on the PC board 100 like ordinary electronic components, and can be used for, for example, a multi-channel noise filter for IC and other uses. In addition, the membrane substrate 10 using the mother substrate as the insulating substrate 10 and the multi-channel noise filter is provided on the PC board 100 can be mounted in a horizontal arrangement without standing as shown in the figure. Even when the PC board 100 is installed in a place where the thickness is restricted, the multi-channel noise filter can be mounted without increasing the thickness of the PC board 100.

In addition, the noise filter of the present invention can be used not only as a noise filter for signal lines but also as a noise filter for power lines, for example, for IC power lines and the like. As described above, it is necessary as an insulating substrate used for the noise filter of the present invention. In some cases, a film- or sheet-shaped insulating substrate or an insulating substrate in other forms may be used.

In addition, this invention is not limited to the said Example, A various deformation | transformation is possible within the range which does not deviate from the summary of this invention.

For example, when the noise filter of the present invention is formed as an SMD type element, a case where sufficient L and C required by one noise filter cannot be obtained. In this case, LC noise filters having arbitrary C and L can be obtained by stacking several noise filters and connecting each noise filter in series or in parallel.

As the substrate 10, a ceramic material used as a varistor may be used as necessary to remove lightning surges and the like.

In each of the above embodiments, the magnetic resistance of the inductor conductor 20 is reduced by adhering the magnetic body to the surface of the inductor conductor 20 by plating or the like to increase the inductance thereof. Moreover, by using an insulating thing as this magnetic body, the short circuit between the conductors 20 can be prevented more effectively.

In the first embodiment, a second inductor conductor having one end grounded is used as a shield for the first inductor conductor 20-1 used as the conducting conductor to prevent its short circuit. In the third embodiment, the first inductor conductor 20-1 and the second inductor conductor 20 used as the conducting conductor using the first and second shielding conductors 30-1 and 30-2. -2) to prevent the line short between. In addition to this, the line short circuit phenomenon is further improved by coating an insulating shielding layer on both the surface 10a of the substrate 10 provided with such a conductor, or both of the surface 10a and the back surface 10b thereof. It can effectively prevent.

In the present embodiment, the substrate 10 is formed by using a material such as a high frequency absorption heating element, thereby absorbing noise, particularly high frequency noise, generated in a signal passing through the inductor conductor 20 as heat. Effective noise cancellation can be performed.

In addition, although the case where the inductor conductor is formed only on one side of the said board | substrate 10 in the said Example was demonstrated as an example, this invention is not limited to this, The board | substrate 10 on both surfaces of the board | substrate 10 as needed. The inductor conductors may be formed spirally so as to face each other with the gap therebetween. In this case, the inductor conductors on the front and back sides are electrically connected to each other to form a noise filter having a large inductance.

In the above embodiment, the case where the dielectric is formed as the substrate 10 has been described as an example. However, the present invention is not limited thereto, and for example, as shown in FIG. A dielectric having the same shape may be used. In this case, a plurality of spiral grooves may be provided on either side of the inner circumference or outer circumference of the cylinder, and an inductor conductor may be formed therein. Moreover, you may form an inductor conductor in both the inner periphery and outer periphery of a cylinder.

As described above, according to the present invention, by adopting a novel configuration in which a plurality of spiral grooves are provided so as to be adjacent to at least one surface of the dielectric, and inductor conductors are provided in each of these grooves, the inductor conductors of each other are opposite to each other. The magnetic flux of the inductor conductor is opposed to each other with the walls located between each spiral groove not interfering with each other. As a result, a distributed integer LC noise filter having sufficient capacitance and excellent electrical characteristics can be obtained without reducing the inductance of each inductor conductor.

In addition, according to the present invention, the ground inductor conductor functions as a shielding conductor to prevent the line short circuit of the inductor conductor for electricity, so that the normal mode LC noise filter can remove the noise component even in the high frequency band without generating the line short circuit. Will be obtained.

In addition, according to the present invention, by providing the first and second shielding conductors between the first and the second inductor conductors used as the conducting conductors to prevent the short circuits between them, a noise component is not generated even in a high frequency band. The common mode LC noise filter can be obtained.

Claims (8)

A dielectric, a plurality of helical grooves formed adjacent to at least one surface of the dielectric, and a plurality of inductor conductors formed in each of the grooves, each inductor conductor having a capacitor between the inductor conductors adjacent to each other across the wall of the dielectric. LC noise filter, characterized in that the formation. The LC noise filter according to claim 1, wherein at least two helical grooves are provided, and a conductive inductor conductor is provided in one of the grooves and a ground inductor conductor is formed in the other groove. The LC noise filter according to claim 1, wherein at least four spiral grooves are provided, the inductor conductor for electricity is provided in two non-adjacent grooves, and the shielding conductor is formed in another groove to form a common mode type. . 4. The method of any one of claims 1 to 3, wherein the dielectric is formed as a substrate, the plurality of spiral grooves are formed adjacent to at least one surface of the substrate, and each inductor conductor is formed in each groove. LC noise filter characterized by the above-mentioned. The LC noise filter according to claim 4, wherein the noise filter comprises a through hole located in the center of the helical groove in the substrate, and a magnetic path is formed on the surface of the substrate using a magnetic material. 6. The dielectric according to any one of claims 1 to 3 or 5, wherein the dielectric is formed as a thick substrate, and the plurality of spiral grooves are formed in a deep groove in the substrate, and each inductor conductor is a deep groove. LC noise filter, characterized in that formed in each spiral groove formed so as to face through the wall surface. 7. The LC noise filter according to claim 6, wherein each of the spiral grooves is formed in a deep groove shape penetrating from one surface of the substrate to the rear surface side. A substrate made of a dielectric and a plurality of LC noise filters disposed adjacent to each other on the substrate, each of the LC noise filters comprising a plurality of spiral grooves formed on at least one surface of the substrate and a plurality of inductors formed in the spiral grooves; And a conductor, wherein each inductor conductor forms a capacitor between the inductor conductors adjacent to each other via a wall of the dielectric.

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