JP2005318103A - Lc circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an LC circuit capable of integrally manufacturing a coil and a capacitor with a simple constitution without using a magnetic body. <P>SOLUTION: The capacitor C and the coil 17 formed of metal are embedded into a depressed hole 11 formed to a substrate 10 in a state of being connected in series. When an upper layer substrate 20 is joined to the surface of the substrate 10, an electrode 22 to be brought into contact formed to the lower face 20A of the upper layer substrate 20 is brought into pressure contact with a contact point 17c of the coil 17, and can be extracted to the outside via a first conductive part 21. The lower electrode 13 of the capacitor C is extracted to the outside via a second conductive part 12. The coil can be formed without using a magnetic body. Therefore, the constitution of the LC circuit can be simplified. The manufacturing processes of the LC circuit can be facilitated. A space on the substrate required for mounting the LC circuit can be reduced since the coil and the capacitor can be integrated. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an LC circuit mounted as an assembly part on a circuit board, and more particularly to an LC circuit in which a coil and a capacitor are integrally arranged.

  LC circuits are frequently used in electronic circuits, as represented by, for example, LC filters and LC resonance circuits.

  Such an LC circuit is generally configured by electrically connecting a coil L and a capacitor C. However, in order to mount these two components independently on a circuit board, a relatively large space is secured. It is required to keep. For this reason, the number of parts cannot be reduced, and there is a problem that it is difficult to reduce the size of the circuit board on which the LC circuit is mounted.

In this respect, for example, in Patent Document 1, a coil in which a thin plate of aluminum foil or the like having a predetermined width is wound concentrically and opposedly is formed, and an insulating paper impregnated with an electrolyte is overlapped between the turns of the coil. An LC filter is disclosed in which an electrolytic capacitor is formed by being spirally wound and inserted, whereby the coil and the capacitor are integrated to reduce the number of parts and reduce the size.
Japanese Utility Model Publication No. 5-95034

  However, in the LC filter described in Patent Document 1 described above, it is troublesome to insert and insert into an opposing spiral so as to overlap insulating paper impregnated with the electrolytic solution between thin plates forming coils, that is, between turns, There is a problem that the manufacturing process tends to be complicated.

  In general, the coil is made of a magnetic material, the capacitor is made of a dielectric, and the other wiring members are made of a conductor. Therefore, a complicated method is required to manufacture the LC circuit integrally. There is also.

  The present invention has been made to solve the above-described conventional problems, and an object thereof is to provide an LC circuit in which a coil and a capacitor can be integrally manufactured with a simple configuration without using a magnetic material.

The present invention is an LC circuit having a capacitor and a coil formed by spirally winding a flat metal, and the capacitor and the coil are embedded in a depression hole formed in a substrate,
The capacitor is formed by one electrode provided on the bottom surface of the coil, the other electrode provided on the bottom surface of the recessed hole, and a dielectric sandwiched between the electrodes. To do.

Further, the present invention is an LC circuit having a capacitor and a coil formed by spirally winding a plate-like metal, and the capacitor and the coil are embedded in a depression hole formed in a substrate. ,
A pair of electrodes opposed to both ends of the coil and a dielectric filling the recessed hole are provided, and the capacitor is formed by the pair of electrodes and the dielectric buried in the electrode. It is characterized by being.

Further, the present invention is an LC circuit comprising a capacitor and a coil formed by spirally winding a flat metal, and the capacitor and the coil are embedded in a recessed hole formed in a substrate. ,
A dielectric film is laminated on one surface of the metal forming the coil, and is sandwiched between the coil and the electrode when an electrode disposed facing the depression hole presses the coil. In addition, a capacitor is formed by the dielectric film.

  In the present invention, a coil can be formed without using a magnetic material. Therefore, since the configuration of the LC circuit can be simplified, the manufacturing process can be facilitated. Moreover, since the coil and the capacitor can be integrated, the space on the substrate necessary for mounting the LC circuit can be reduced.

  In the above, the coil is formed so as to be concentrically wound or wound in a convex spiral shape in which the diameter of the coil gradually decreases from one end to the other end. preferable.

  In this case, the lead-out line from the LC circuit has a first conductive portion provided with an electrode extending from the outside of the depression hole to the bottom surface and connected to one end of the coil or capacitor. And a second conductive portion having an electrode extending from the outside of the depression hole to the opening end of the depression hole and electrically contacting the other end portion of the coil without being in contact with each other. Can be configured.

  More specifically, the substrate is a multilayer substrate in which an upper layer substrate is laminated on the surface of a lower layer substrate, the depression hole and the first conductive part are provided on the opposite surface side of the lower layer substrate, and the upper layer The second conductive portion may be provided on the opposite surface of the substrate.

  Alternatively, an electrode is formed on the bottom surface of the electronic component, and the other end portion of the coil is electrically connected to the electrode by fixing the electronic component to the substrate. .

  In the present invention, since the coil can be formed without using a magnetic material, the configuration of the LC circuit can be simplified. Therefore, the manufacturing process of the LC circuit can be facilitated.

  Moreover, since the coil and the capacitor can be integrated, the space on the substrate necessary for mounting the LC circuit can be reduced.

  FIG. 1 is a cross-sectional view of a circuit board showing an LC circuit according to a first embodiment of the present invention, in which A is a state before joining an upper layer substrate to a lower layer substrate, and B is an upper layer substrate joined to a lower layer substrate. The state of the subsequent multilayer substrate is shown. FIG. 2 is a plan view showing the coil, and FIG. 3 is a circuit configuration diagram equivalently showing the LC circuit of the first embodiment.

  As shown in FIG. 1, the LC circuit shown as the first embodiment is formed inside a depression hole 11 formed in a substrate 10 such as a PWB (Print Wire Board).

  The substrate 10 is provided with a first conductive portion 12 formed by printing a copper foil or the like. A lower electrode (the other electrode) 13 is formed in a predetermined area on the bottom surface 11a of the depression hole 11, and the first conductive portion 12 passes through the wall surface 11b of the depression hole 11 from the outside of the depression hole 11. Connected to the lower electrode 13.

  A dielectric 14 is formed with a predetermined film thickness on the surface of the lower electrode 13, and an upper electrode (one electrode) 16 is provided on the surface of the dielectric 14. The lower electrode 13 and the upper electrode 16 form a pair of parallel electrodes. And the capacitor | condenser C is formed by providing the said dielectric material 14 between the said pair of parallel electrodes.

  A coil 17 is provided on the surface of the upper electrode 16. The coil 17 shown in this embodiment has an outer frame portion 17A on the outer peripheral side as shown in FIGS. 1 and 2, for example, and an elastically deformable portion 17a extending spirally from the inside of the outer frame portion 17A toward the center. It is a spiral coil provided with. The elastic deformation portion 17a is formed of a flat metal, for example, nickel or an alloy of nickel and copper, and a coil is formed from the base end portion 17b on the outer frame portion 17A side toward the contact portion 17c on the Z1 side. It is formed in a convex spiral shape whose diameter gradually decreases. However, it may be a concentric spiral coil in which the diameter of the coil is constant on the base end portion 17b side and the contact portion 17c side.

  In the coil 17, the outer frame portion 17A is fixed to the upper electrode 16 forming the capacitor C with a conductive adhesive or the like. Further, the contact portion 17c of the coil 17 is installed in a state of protruding from the opening end 11A of the recessed hole 11 in the Z1 direction in the drawing. In FIG. 1, the length dimension of the coil 17 in the Z direction is indicated by H1.

  As shown in FIG. 1B, for example, an upper substrate 20 is bonded to the surface (opposing surface) 10 </ b> A of the substrate 10. In this case, the substrate 10 serves as a lower layer substrate, and the substrate (lower layer substrate) 10 and the upper layer substrate 20 form a multilayer substrate.

  A second conductive portion 21 formed by printing a copper foil or the like is provided on the lower surface (facing surface) 20A of the upper layer substrate 20 that is the facing surface of the surface 10A of the substrate 10. At the tip of the second conductive portion 21, a contacted electrode 22 whose area is expanded is provided at a position facing the recessed hole 11.

  As shown in FIG. 1B, when the upper substrate 20 is laminated and fixed on the substrate (lower substrate) 10, the contact portion 17c of the coil 17 is pressed in the Z2 direction by the contacted electrode 22, so that the coil The 17 elastically deformable portions 17a are fixed in a contracted state in the length direction H2 (H2 <H1) in the Z2 direction. At this time, the contact portion 17c of the coil 17 strongly press-contacts the contacted electrode 22 by the elastic force of the elastic deformation portion 17a, so that the contact portion 17c of the coil 17 and the contacted electrode 22 are electrically connected. Can be secured.

  Further, since the length dimension H2 of the coil 17 at this time is defined by the distance between the upper electrode 16 of the capacitor C and the contacted electrode 22, the inductance value can be set to a value almost as designed. it can.

  As shown in the equivalent circuit of FIG. 3, in the LC circuit of the first embodiment, a coil 17 and a capacitor C are connected in series. At this time, the first conductive portion 12 is a lead wire connected to the lower electrode 13 of the capacitor C. Similarly, the second conductive portion 21 is connected to the contact portion 17c of the coil 17 via the contacted electrode 22. It can function as a leader line.

  In the first embodiment, a multilayer substrate in which the upper layer substrate 20 is stacked on the upper surface of the substrate 10 is shown. However, in the case of a single layer substrate, an electronic component is replaced with the recessed hole 11 instead of the upper layer substrate 20. It should be fixed on the top. That is, by fixing the potential component to the surface of the substrate 10 so as to cover the depression 11 while the electrode provided on the bottom surface of the electronic component is in contact with the contact portion 17c of the coil 17, the same LC as described above. It can be a circuit. In this case, reference numeral 20 shown in FIGS. 1A and 1B functions as an electronic component, and reference numerals 21 and 22 function as electrodes provided on the bottom surface of the electronic component.

Next, an LC circuit as a second embodiment will be described.
FIG. 4 is a cross-sectional view showing an LC circuit as a second embodiment of the present invention, and FIG. 5 is a circuit configuration diagram equivalently showing the LC circuit shown in the second embodiment.

  In FIG. 4, a spiral coil 17 is provided in a recessed hole 11 provided in the substrate 10, and the contacted electrode 22 on the lower surface 20A of the upper substrate 20 is in contact with the contact portion 17c of the coil. Is the same as in the first embodiment.

  However, the outer frame portion 17A of the coil 17 is fixed to the lower electrode 13 of the bottom surface 11a of the recessed hole 11 with a conductive adhesive or the like, and the dielectric 14 is formed in the recessed hole 11 and around the coil 17. Is different in that it is embedded.

  That is, the dielectric 14 is provided so as to fill the space between the contacted electrode 22 and the lower electrode 13, and is embedded in a region where the lower electrode 13 and the contacted electrode 22 face each other. A capacitor C is formed by the dielectric 14.

  Further, since the stray capacitance can be positively generated between the turns of the coil 17, the capacitor C can be formed by each stray capacitance.

  Therefore, in the LC circuit shown in the second embodiment, the capacitor C is equivalently connected to both ends of the coil 17, so that the coil 17 and the capacitor C are connected in parallel as shown in FIG. Can be configured.

  In this case, the first conductive portion 12 is a lead wire connected to one end of the capacitor C and the coil 17, and the second conductive portion 21 is similarly connected to the other end of the capacitor C and the coil 17. Functions as a connected leader line.

  In this case as well, as in the first embodiment, an LC circuit can be configured by using an electronic component and an electrode provided on the bottom surface instead of the upper substrate 20.

Next, an LC circuit as a third embodiment will be described.
FIG. 6 is a cross-sectional view showing an LC circuit as a third embodiment of the present invention.

  In the LC circuit shown in the third embodiment shown in FIG. 6, the spiral coil 17 is provided in the recessed hole 11 provided in the substrate 10, and the outer frame portion 17 </ b> A of the coil 17 is provided in the recessed hole 11. This is the same as the second embodiment in that the lower electrode 13 provided on the bottom surface 11a is fixed with a conductive adhesive or the like.

  However, in the third embodiment, instead of the depression 11 being filled with the dielectric 14, the surface of the metal forming the coil 17 (the surface on the Z1 side) has a predetermined film thickness. The difference is that the formed dielectric film 14A is coated. The dielectric film 14A is formed with a uniform film thickness by applying a resin material having a relatively high dielectric constant, such as polyimide resin, to the surface of the coil 17.

  The coil 17 is depressed in a state where the elastically deformable portion 17a is greatly contracted in the Z2 direction more than in the case of FIG. 1 by the contacted electrode 22 provided on the opposing surface (lower surface) of the upper substrate 20. It is provided in the hole 11. Therefore, not only the dielectric film 14A on which the surface of the contact portion 17c is laminated, but also the dielectric film 14A that is laminated on the surface of the elastic deformation portion 17a in the vicinity of the contact portion 17c. They are touching at the same time. Therefore, in the third embodiment, the dielectric film 14A that is in contact with the contacted electrode 22 and the contact portion 17c, the elastic deformation portion 17a, and the contacted electrode 22 that sandwich the dielectric film 14A from the vertical (Z) direction. A capacitor C is formed. In this case, the equivalent circuit of the LC circuit is connected in series as in FIG. 3 because the capacitor C is connected to the tip of the coil 17.

  In this case as well, as in the first embodiment, an LC circuit can be configured by using an electronic component and an electrode provided on the bottom surface instead of the upper substrate 20.

  As described above in each embodiment, in the present invention, since the LC circuit composed of the capacitor C and the coil 17 can be integrated into the recessed hole 11 of the substrate 10, the LC circuit is mounted on the substrate 10. Therefore, the space required for this can be reduced as compared with the prior art. In addition, since it is not necessary to use a magnetic material as the coil L, it is possible to simplify the manufacturing process of the LC circuit.

  In each of the above-described embodiments, the elastic deformation portion 17a is formed of a flat metal, and the coil is formed from the base end portion 17b on the outer frame portion 17A side toward the contact portion 17c on the Z1 side. Although the one formed by a spiral spiral coil having a gradually decreasing diameter is shown, the present invention is not limited to this, and the diameter of the coil is constant on the base end portion 17b side and the contact portion 17c side. A certain concentric spiral coil may be sufficient.

1 is a cross-sectional view of a circuit board showing an LC circuit according to a first embodiment of the present invention, in which A is a state before bonding an upper layer substrate to a lower layer substrate, and B is a multilayer after the upper layer substrate is bonded to the lower layer substrate. The state of the board, A plan view showing the coil, The circuit block diagram which equivalently shows LC circuit of 1st Embodiment, Sectional drawing which shows LC circuit as the 2nd Embodiment of this invention, A circuit configuration diagram equivalently showing the LC circuit shown in the second embodiment; Sectional drawing which shows LC circuit as the 3rd Embodiment of this invention,

Explanation of symbols

10 Substrate (lower layer substrate)
10A Substrate surface (opposite surface)
11 depression hole 12 first conductive part 13 lower electrode (the other electrode)
14 Dielectric 14A Dielectric film 16 Upper electrode (one electrode)
17 Coil 17A Outer frame portion 17a Elastic deformation portion 17b Base end portion 17c Contact portion 20 Upper layer substrate 20A Lower surface (opposite surface) of upper layer substrate
21 Second conductive portion 22 Contacted electrode

Claims (7)

An LC circuit having a capacitor and a coil formed by spirally winding a flat metal, wherein the capacitor and the coil are embedded in a recessed hole formed in a substrate,
The capacitor is formed of one electrode provided on the bottom surface of the coil, the other electrode provided on the bottom surface of the recessed hole, and a dielectric sandwiched between the electrodes. LC circuit to do. An LC circuit having a capacitor and a coil formed by spirally winding a flat metal, wherein the capacitor and the coil are embedded in a recessed hole formed in a substrate,
A pair of electrodes opposed to both ends of the coil and a dielectric filling the recessed hole are provided, and the capacitor is formed by the pair of electrodes and the dielectric buried in the electrode. LC circuit characterized by being made. An LC circuit having a capacitor and a coil formed by spirally winding a flat metal, wherein the capacitor and the coil are embedded in a recessed hole formed in a substrate,
A dielectric film is laminated on one surface of the metal forming the coil, and is sandwiched between the coil and the electrode when an electrode disposed facing the depression hole presses the coil. An LC circuit, wherein a capacitor is formed by the dielectric film.   The coil is formed by being wound in a concentric spiral shape or by being wound in a convex spiral shape in which the diameter of the coil gradually decreases from one end to the other end. The LC circuit according to any one of the above.   The depression hole includes a first conductive portion having an electrode extending from the outside of the depression hole to the bottom surface and connected to one end of the coil or capacitor, and the depression hole from the outside of the depression hole. The LC according to any one of claims 1 to 4, wherein a second conductive part that includes an electrode that extends to an open end and electrically contacts the other end of the coil is provided in a state of not contacting each other. circuit.   The substrate is a multilayer substrate in which an upper layer substrate is laminated on the surface of a lower layer substrate, the depression hole and the first conductive portion are provided on the facing surface side of the lower layer substrate, and the facing surface of the upper layer substrate is The LC circuit according to claim 5, wherein a second conductive portion is provided.   The LC according to claim 5, wherein an electrode is formed on a bottom surface of the electronic component, and the other end of the coil is electrically connected to the electrode by fixing the electronic component to the substrate. circuit.

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