JP4069067B2 - Capacitor - Google Patents

Description

  The present invention relates to a capacitor.

  As a capacitor configured by mounting a capacitor element on a substrate, for example, an electrolytic capacitor described in Patent Document 1 is known.

  In the electrolytic capacitor described in Patent Document 1, a through hole is formed in a substrate on which a capacitor element is mounted. A first electrode connected to the anode part of the capacitor element and a second electrode connected to the cathode part are provided on the surface of the substrate. A first external electrode paired with the first electrode and a second external electrode paired with the second electrode are formed on the back surface of the substrate.

The first electrode and the second electrode and the corresponding first external electrode and second external electrode are electrically connected through a through hole formed in the substrate. Therefore, the anode part and the cathode part of the capacitor element are electrically connected to the first external electrode and the second external electrode provided on the back surface of the substrate through the through holes.
JP 2001-102252 A

  Incidentally, in recent years, in order to reduce the impedance of electrolytic capacitors, there is an increasing demand for a reduction in equivalent series resistance (ESR). In the electrolytic capacitor having the above configuration, the effect of reducing the ESR tends to be achieved as the number of through holes increases.

  Therefore, in order to form a large number of through holes in the substrate extending in one direction, the present inventors extend the first and second electrodes in the longitudinal direction of the substrate, and in parallel with the longitudinal direction, It has been noted that the first and second external electrodes on the back surface side have the same arrangement corresponding to the arrangement.

  However, if the first and second external electrodes extend in the longitudinal direction of the substrate and are juxtaposed in the longitudinal direction, the space between the first and second external electrodes becomes narrow. Therefore, there arises a problem that workability when the capacitor is mounted on the substrate is deteriorated.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a capacitor with good workability when mounted on a substrate.

In order to solve the above problems, a capacitor according to the present invention includes a capacitor element having an anode part and a cathode part, and a substrate having an element mounting area extending in one direction in which the capacitor element is mounted. The substrate includes a substrate body in which first and second conductive paths penetrating from the front surface to the back surface are formed, and a first electrode and a cathode provided in an element mounting region on the surface and connected to an anode portion A second electrode connected to the first portion, a first external electrode provided on the back surface and electrically connected to the first electrode through the first conductive path, and a second electrode through the second conductive path A second external electrode electrically connected, the first electrode and the second electrode extend in the longitudinal direction of the element mounting region, and are arranged in parallel in a direction intersecting the longitudinal direction, The first external electrode and the second external electrode are connected to wiring outside the system. Has a first connection region and a second connection area for connection, the first connection region and the second connection region are parallel to the longitudinal direction, the first connection region, the back surface Is formed on one end side of both end portions in the longitudinal direction of the element mounting region in a region corresponding to the element mounting region, and the second connection region is formed on the other end side of the both end portions. A plurality of first conductive paths are arranged along the edge of the first electrode on the second electrode side, and the second conductive path is formed on the first electrode side of the second electrode. It is characterized in that a plurality are arranged along the edge .

In this capacitor, since the first and second electrodes are arranged as described above, a large number of first and second conductive paths can be formed in the longitudinal direction of the element mounting region. Further, since the first connection region and the second connection region are arranged in parallel in the longitudinal direction of the element mounting region, the distance between the first connection region and the second connection region can be further increased. . Furthermore, since the first connection region is formed on one end side of both end portions in the longitudinal direction of the element mounting region on the back surface, and the second connection region is formed on the other end portion side of both end portions, The space between the first and second connection regions can be increased. Therefore, the first and second connection regions can be used for improving workability when a capacitor is mounted on another circuit board or the like. Further, since the first and second conductive paths are formed as described above, the first and second conductive paths are closer to each other, and the equivalent series inductance (ESL) is reduced. Further, as described above, since a large number of first and second conductive paths can be taken, ESL tends to be further reduced.

  Furthermore, in the capacitor according to the present invention, the region other than the first connection region in the first external electrode and the region other than the second connection region in the second external electrode are covered with an insulating material. Preferably it is. In this case, almost all of the regions other than the first connection region and the second connection region can be used for improving the workability described above.

  In the capacitor according to the present invention, it is preferable that the first conductive path and the second conductive path are arranged in parallel in a direction substantially orthogonal to the longitudinal direction of the element mounting region. In this case, since the first and second conductive paths are closer to each other, ESL is more likely to be reduced.

  In the capacitor according to the present invention, the first conductive path and the second conductive path are formed between the first connection region and the second connection region, and the first external electrode is A first conductive region extending from the first connection region toward the second connection region so as to cover a region where the first conductive path is formed on the back surface; A second conductive region extending from the second connection region toward the first connection region so as to cover a region where the second conductive path is formed; the first conductive region and the second conductive region; Is preferably parallel to the direction intersecting the longitudinal direction of the element mounting region. In this case, since the direction of the current flowing through the first conduction region and the second conduction region is reversed, ESL is likely to be reduced.

  According to the present invention, it is possible to provide a capacitor with good workability when mounted on a substrate.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the following description, the same reference numerals are used for the same elements, and duplicate descriptions are omitted.

  FIG. 1 is a schematic perspective view showing the capacitor of this embodiment. As shown in FIG. 1, the capacitor 1 includes a capacitor element 10 and a substrate 20 having an element mounting area α that is an area for mounting the capacitor element 10 and extends in one direction. In the present embodiment, the capacitor 1 is an electrolytic capacitor. Further, since the substrate 20 has a substantially rectangular flake shape extending in one direction as shown in FIG. 1, the region defined by the outer periphery of the substrate 20 corresponds to the element mounting region α.

  In the present specification, the long side direction (longitudinal direction of the element mounting region) of the substrate 20 is described as the X direction, the short side direction is defined as the Y direction, and the direction orthogonal to the X direction and the Y direction is described as the Z direction.

  The capacitor element 10 includes an anode part 11 and a cathode part 12. The shape of the cathode portion 12 is a substantially rectangular thin piece extending in the X direction as shown in FIG. The anode 11 protrudes outward (Y direction) from the edge of the cathode 12 that extends in the X direction. An insulating portion 13 made of an insulating material is provided between the anode portion 11 and the cathode portion 12 in order to prevent short circuit between them.

  FIG. 2 is a schematic diagram showing a cross-sectional configuration of the capacitor element 10 along the line II-II in FIG.

  The anode part 11 is composed of a partial region of an aluminum substrate (valve metal substrate) 15 having a dielectric layer 14 formed on the surface layer. The dielectric layer 14 is an aluminum oxide film, and is formed by subjecting the aluminum substrate 15 to roughening (enlargement) by etching and then chemical conversion, that is, anodic oxidation.

  The cathode portion 12 includes an electrolyte layer 16 that covers a region of the aluminum substrate 15 excluding the anode portion 11, and a conductor layer 17 formed around the electrolyte layer 16.

  The electrolyte layer 16 includes a conductive polymer compound. The electrolyte layer 16 is formed by impregnating the material to be the electrolyte layer 16 in a monomer state in the concave portion of the roughened surface of the aluminum substrate 15 and then performing chemical oxidation polymerization or electrolytic oxidation polymerization. .

  The conductor layer 17 includes a graphite paste layer 18 and a silver paste layer 19 which are sequentially formed on the electrolyte layer 16 by any one of a screen printing method, a dipping method and a spray coating method, for example. In the capacitor element 10, the electrolyte layer 16 and the conductor layer 17 function as a cathode.

  Next, the substrate 20 on which the capacitor element 10 is mounted will be described with reference to FIGS. FIG. 3 is a schematic diagram showing a cross-sectional configuration of the capacitor 1 along the line III-III in FIG. FIG. 4A is a plan view of the substrate 20 on the side where the capacitor element 10 is mounted. FIG. 4B is a plan view of the substrate 20 on the side opposite to FIG. 4A.

  The substrate 20 is made of an epoxy resin and has a substrate body 30 having a substantially rectangular flake shape. In this specification, the surface of the substrate body 30 on which the capacitor element 10 is mounted is referred to as a front surface 31, and the surface opposite to the front surface 31 is referred to as a back surface 32.

  The substrate 20 is a printed wiring board in which the first electrode 40A and the second electrode 40B made of copper are printed on the front surface 31, and the first outer electrode 50A and the second outer electrode 50B made of copper are printed on the back surface 32. is there.

  The first electrode 40 </ b> A is connected to the anode portion 11 of the capacitor element 10. The first electrode 40A and the first external electrode 50A are electrically connected through a through hole (first conductive path) 33A penetrating from the front surface 31 to the back surface 32 of the substrate body 30. The second electrode 40B is connected to the cathode portion 12 of the capacitor element 10. The second electrode 40B and the second external electrode 50B are electrically connected through a through hole (second conductive path) 33B penetrating from the front surface 31 to the back surface 32.

  As shown in FIGS. 3 and 4A, a plurality of through holes 33A are in contact with the edge 41A on the second electrode 40B side of the first electrode 40A and are arranged in the X direction. Further, a plurality of through holes 33B are in contact with the edge portion 41B on the first electrode 40A side of the second electrode 40B and are arranged in the X direction. Further, the pair of through holes 33A and the through holes 33B are arranged in parallel in the Y direction. The through holes 33A and 33B are configured by filling a hole penetrating from the front surface 31 to the back surface 32 with a conductive material.

  As shown in FIG. 4A, the first electrode 40A and the second electrode 40B are substantially rectangular and are juxtaposed in the Y direction. The length of the second electrode 40B in the Y direction is longer than the length of the first electrode 40A in the Y direction, and the occupied area of the second electrode 40B on the surface 31 is larger than the occupied area of the first electrode 40A. ing.

  Further, the first electrode 40A and the second electrode 40B are insulating films 60 (shaded portions in FIG. 4A) made of an insulating material such as solder resist from the edge 41A to the edge 41B. It is covered. The insulating film 60 also enters (between) the first electrode 40A and the second electrode 40B. Thus, by providing the insulating film 60, when the capacitor element 10 is mounted on the substrate 20, the cathode portion 12 is short-circuited to the first electrode 40A, or the anode portion 11 is short-circuited to the second electrode 40B. Is prevented. Further, the insulating film 60 is formed so that the width in the X direction is wider than the width of the first and second electrodes 40A and 40B, and covers the surface 31 as well.

  As shown in FIG. 4B, the shape of the first external electrode 50A and the second external electrode 50B is substantially L-shaped. The first and second external electrodes 50A and 50B are arranged so as to fit each other. However, the first and second external electrodes 50A and 50B are isolated.

  The first and second external electrodes 50A and 50B have a rectangular insulating film 61 extending in the Y direction including the boundary and the region covering the through holes 33A and 33B (FIG. 4B). It is covered with the hatched part in the middle. The insulating film 61 also enters (between) the first and second external electrodes 50A and 50B in order to more reliably electrically insulate the first and second external electrodes 50A and 50B. It is out. Further, the insulating film 61 is formed so that the width in the Y direction is wider than the width of the first external electrodes 50A and 50B, and also covers the back surface 32.

  A region of the first external electrode 50A that is not covered with the insulating film 61, that is, an exposed region is connected to a wiring (for example, another circuit board) outside the system (that is, outside the capacitor 1). This is the first connection region 51A. In addition, a region of the second external electrode 50B that is not covered with the insulating film 61, that is, an exposed region is a second connection region 51B for connection to a wiring outside the system.

  The first connection region 51A is formed on one end portion 34 side of both end portions 34, 35 in the longitudinal direction in the element mounting region α of the back surface 32, and extends in the Y direction. In the present embodiment, the entire back surface 32 is a region corresponding to the element mounting region α. Further, the second connection region 51B is formed on the end portion 35 side that makes a pair with the end portion 34, and extends in the Y direction. The first connection region 51 </ b> A and the second connection region 51 </ b> B are arranged in parallel in the longitudinal direction of the substrate 20. Further, the length of the first and second connection regions 51A and 51B in the Y direction is substantially equal to the length of the substrate 20 in the Y direction.

  In the first external electrode 50A, the region other than the first connection region 51A is a first conduction region 52A that is directly connected to the plurality of through holes 33A. The first conduction region 52A extends from the first connection region 51A toward the second connection region 51B so as to cover a region where the plurality of through holes 33A are formed on the back surface 32.

  In the second external electrode 50B, the region other than the second connection region 51B is a second conduction region 52B that is directly connected to the plurality of through holes 33B. The second conduction region 52B extends from the second connection region 51B toward the first connection region 51A so as to cover a region where the plurality of through holes 33B are formed on the back surface 32.

  As shown in FIG. 4B, the first conduction region 52A and the second conduction region 52B are arranged in parallel in the Y direction and are covered with an insulating film 61.

  Next, a method for manufacturing the capacitor 1 of FIG. 1 by mounting the capacitor element 10 on the substrate 20 will be described. First, the capacitor element 10 is mounted on the substrate 20 so that the anode portion 11 of the capacitor element 10 is in contact with the first electrode 40A and the cathode portion 12 is in contact with the second electrode 40B.

  Next, the cathode part 12 and the second electrode 40B are connected using, for example, a conductive adhesive. Thereby, the cathode part 12 and the 2nd electrode 40B are electrically connected. Since the second electrode 40B is electrically connected to the second external electrode 50B through the through hole 33B, the cathode and the second external electrode 50B are electrically connected.

  Subsequently, the anode part 11 and the first electrode 40A are connected by metal welding means such as YAG laser spot welding. Thereby, the aluminum base 15 constituting the anode part 11 and the first electrode 40A are electrically connected. Since the first electrode 40A is electrically connected to the first external electrode 50A through the through hole 33A, the aluminum base 15 and the first external electrode 50A are electrically connected.

  Therefore, it is possible to charge and discharge the capacitor element 10 by connecting wiring outside the system to the first connection region 51A and the second connection region 51B.

  In the capacitor 1, since the through holes 33A and 33B are arranged as described above, the through hole 33A and the through hole 33B are closer to each other, and ESL is reduced. In addition, since the first and second electrodes 40A and 40B extend in the longitudinal direction of the substrate 20, more through holes 33A and 33B can be provided. Therefore, ESL is further reduced.

  Further, in the first electrode, when the length in the direction substantially orthogonal to the extending direction (the length in the Y direction in FIG. 4A) is constant, the first electrode 40A is more than in the Y direction. The area extending in the X direction has a larger area of the first electrode 40A. For this reason, the connection strength between the first electrode 40A and the anode portion 11 is increased by using the arrangement as shown in FIG.

  Next, the operation and effect of the first and second connection regions 51A and 51B being arranged in parallel in the X direction will be described.

  In this case, since the distance between the first and second connection regions 51A and 51B can be increased, the region covered with the insulating film 61 can be increased. Thereby, a wide working area can be secured, and workability when the capacitor 1 is mounted on another circuit board or the like is improved.

  For example, when a capacitor is mounted on another circuit board by reflow soldering, when the temperature around the capacitor rises, the so-called tower phenomenon is known in which the capacitor rises with respect to the circuit board mounting surface. ing. In the capacitor 1, since the distance between the first and second connection regions 51A and 51B is wide, it is easy to apply an adhesive therebetween. As a result, the capacitor 1 can be fixed and soldered to the circuit board with an adhesive, so that the tower can be prevented and the capacitor 1 can be easily mounted on the circuit board. In addition, when the capacitor 1 is manually mounted on the circuit board, the area covered with the insulating film 61 is wide, and therefore, soldering while holding the capacitor 1 with tweezers using the area. And soldering becomes easy.

  By the way, normally, the first and second external electrodes are formed in correspondence with the arrangement pattern of the first and second electrodes 40A and 40B. Therefore, if the first and second electrodes 40A, 40B are arranged as shown in FIG. 4A, the first and second external electrodes are conventionally arranged in the same manner. In this case, since the two electrodes are arranged in the Y direction, the space between the first and second external electrodes becomes narrow. Therefore, the workability at the time of mounting the substrate as described above is deteriorated.

  In contrast, in the present embodiment, the first and second connection regions 51A and 51B are formed in the arrangement shown in FIG. 4B, so that the capacitor 1 with good workability can be obtained while achieving low ESL. ing.

  Moreover, on the surface of the substrate extending in one direction, the first and second electrodes are generally arranged in parallel in the X direction in order to increase the capacitance of the capacitor element. As described above, in general, the arrangement pattern of the back side electrode corresponds to the arrangement pattern on the front side. Therefore, conventionally, the first and second external electrodes are often arranged in parallel in the X direction. The connection technology is compatible with such an arrangement pattern.

  Therefore, the first and second connection regions 51A and 51B are arranged as shown in FIG. 4B while the arrangement pattern of the first and second electrodes 40A and 40B is shown in FIG. The versatility of connection with the outside of 1 is expanding.

  Further, in the present embodiment, since the first connection region 51A is formed on the end portion 34 side and the second connection region 51B is formed on the end portion 35 side, the number of through holes 33A and 33B is further increased. can do. Therefore, as described above, ESL is further reduced.

  Furthermore, since the first conduction region 52A and the second conduction region 52B are formed as described above, the directions of the currents flowing through the first conduction region 52A and the second conduction region 52B are also reversed. Therefore, ESL is likely to be reduced.

  As mentioned above, although preferred embodiment of this invention was described, it cannot be overemphasized that this invention is not limited to the said embodiment. For example, although an aluminum substrate is used as the valve metal substrate, it may be a substrate composed of a valve metal such as tantalum, niobium, titanium, hafnium, zirconium, zinc, tungsten, bismuth, and antimony.

  Further, the through holes 33A and 33B are configured such that the hole portion penetrating from the front surface 31 to the back surface 32 is filled with the conductive material. For example, only the inner wall surface of the hole portion is made of the conductive material made of the conductive material. A layer may be formed.

  Further, the first external electrode 50A and the second external electrode 50B are not necessarily L-shaped. The first external electrode 50A will be described. The length (width) in the Y direction of the first conduction region 52A is long enough to cover the plurality of through-holes 33A, and the first connection region 51A extends from the first connection region 51A. The convex shape may extend toward the second connection region 51B. The same applies to the second external electrode 50B. When the width of the first conductive region 52A is sufficient to cover the through hole 33A and the width of the second conductive region 52B is sufficient to cover the through hole 33B, the first and second connection regions 51A, In order to form 51B, the insulating film 61 may not cover the first and second external electrodes 50A and 50B.

  Furthermore, although the board | substrate 20 was made into the substantially rectangular thin piece shape, the shape of the board | substrate 20 is not specifically limited. It is only necessary to have an element mounting area for mounting the capacitor element 10 and extending in one direction. When the shape of the substrate (that is, the substrate body) is not a substantially rectangular flake, the first and second conductive paths are formed in the element mounting region in the substrate body, and the first and second electrodes are provided. Just do it.

  Moreover, the anode part 11 and the cathode part 12 in the capacitor | condenser element 10 are not restricted to a form as shown in FIGS. For example, a lead or the like may be drawn from the substantially rectangular thin piece of cathode portion 12, and the cathode portion 12 and the lead may be used as one cathode portion. The same applies to the anode part 11.

  The capacitor 1 is preferably an electrolytic capacitor, but is not limited to an electrolytic capacitor, and may be any capacitor that is used by being mounted in an element mounting region extending in one direction.

It is a schematic perspective view of the capacitor according to the present embodiment. It is a schematic diagram which shows the cross-sectional structure of the capacitor | condenser element along the II-II line | wire in FIG. It is a schematic diagram which shows the cross-sectional structure of the capacitor | condenser along the III-III line in FIG. FIG. 4A is a plan view of the substrate mounting side of the capacitor element. FIG. 4B is a plan view of the opposite side of the substrate from FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Capacitor, 10 ... Capacitor element, 11 ... Anode part, 12 ... Cathode part, 14 ... Dielectric layer, 15 ... Aluminum base | substrate (valve metal base | substrate), 16 ... Electrolyte layer, 17 ... Conductor layer, 20 ... Substrate, DESCRIPTION OF SYMBOLS 30 ... Board | substrate body, 31 ... Front surface, 32 ... Back surface, 33A ... Through hole (1st conductive path), 33B ... Through hole (2nd conductive path), 50A ... 1st external electrode, 50B ... 2nd External electrode, 51A, first connection region, 51B, second connection region, α, element mounting region.

Claims (4)

A capacitor element having an anode part and a cathode part;
A substrate having an element mounting area extending in one direction in which the capacitor element is mounted;
The substrate is
A substrate body formed with first and second conductive paths penetrating from the front surface to the back surface;
A first electrode connected to the anode part and a second electrode connected to the cathode part, provided in the element mounting region on the surface;
A first external electrode provided on the back surface and electrically connected to the first electrode through the first conductive path and electrically connected to the second electrode through the second conductive path A second external electrode;
The first electrode and the second electrode extend in a longitudinal direction of the element mounting region and are arranged in parallel in a direction intersecting the longitudinal direction,
The first external electrode and the second external electrode have a first connection region and a second connection region for connecting to a wiring outside the system,
The first connection region and the second connection region are parallel to the longitudinal direction,
The first connection region is formed on one end side of both end portions in the longitudinal direction in the element mounting region of the region corresponding to the element mounting region on the back surface,
The second connection region is formed on the other end side of the both end portions,
A plurality of the first conductive paths are arranged along an edge of the first electrode on the second electrode side, and the second conductive path is the first electrode of the second electrode. A capacitor , wherein a plurality of capacitors are arranged along the side edge . A region other than the first connection region in the first external electrode and a region other than the second connection region in the second external electrode are covered with an insulating material. The capacitor according to claim 1 .
Ndensesa. The capacitor according to claim 2 , wherein the first conductive path and the second conductive path are arranged in parallel in a direction substantially orthogonal to the longitudinal direction of the element mounting region. The first conductive path and the second conductive path are formed between the first connection region and the second connection region,
The first external electrode has a first conduction region extending from the first connection region toward the second connection region so as to cover a region of the back surface where the first conductive path is formed. Have
The second external electrode has a second conduction region extending from the second connection region toward the first connection region so as to cover a region of the back surface where the second conductive path is formed. Have
Wherein the first conductive region and the second conductive region, in any one of claims 1 to 3, characterized in that in parallel in a direction crossing the longitudinal direction of the element mounting area The capacitor described.

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