JP2009027186A - Capacitor and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the drawbacks when packaging a capacitor, and to improve the defects of the characteristics thereof. <P>SOLUTION: The area of an internal electrode plate 12 inside the capacitor 20 is wider than that of a dielectric plate 11, and an upper face of the dielectric plate 11 is jointed at substantially the center of the lower face of the internal electrode plate 12. One end of the lower face of the internal electrode plate 12 is jointed to a first anode terminal 6. An end of the first anode terminal 6 is exposed to the outside from a mold 13. Furthermore, the other end of the lower face of the internal electrode plate 12 is jointed to a second anode terminal 7. An end of the second anode terminal 7 is exposed to the outside from the mold 13. A first cathode terminal 21 is jointed to a portion between the center of the lower face of the dielectric plate 11 and an end close to the first anode terminal 6. An end of the first cathode terminal 21 is exposed to the outside from the mold 13. Furthermore, a second cathode terminal 22 is jointed to a portion between the center of the lower face of the dielectric plate 11 and an end close to the second anode terminal 7. An end of the second cathode terminal 22 is exposed to the outside from the mold 13. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a capacitor and an electronic device used for a high-frequency electronic circuit.

Conventionally, as disclosed in Patent Document 1, for example, a capacitor in which an electrode is attached to a dielectric plate is used in an electronic circuit. For example, such a capacitor is provided between the power supply lines of the electronic device, and has an effect of removing noise between the power supply lines.
JP 2000-299259 A

  In the capacitor as described above, an electrode is attached to a region occupying most of the flat plate portion of the dielectric plate, and this is exposed to the outside. That is, when this capacitor is mounted on the circuit board, most of the back surface of the capacitor is covered with the exposed portion of the electrode. When such a capacitor is mounted on a circuit board, it is impossible to provide a through hole or form another wiring pattern in the circuit board located under the aforementioned electrode.

  In recent years, for example, there is an electronic device that operates at a so-called high frequency as represented by a personal computer. When the capacitor described above is provided between the power supply lines of the equipment, the frequency characteristics of the impedance of the capacitor in the high frequency range are worse than the frequency characteristics of the impedance in the low frequency range due to the influence of the inductance of the terminal portion of the capacitor.

  Therefore, an object of the present invention is to provide a capacitor and an electronic device that can improve deficiencies in mounting and characteristics.

  That is, the capacitor according to the present invention includes a first anode terminal exposed along a predetermined direction from one end of the first internal electrode joined to one side of the dielectric, and the first internal terminal. The second anode terminal exposed from the other end of the electrode along the predetermined direction described above, and the second internal electrode connected to the other side of the dielectric and independent of the first internal electrode. A terminal exposed from the predetermined portion to the inside of the exposed portion of the first and second anode terminals along the predetermined direction described above, and is connected to the first ground through hole provided in the circuit board. The first cathode terminal, which is a terminal connected to a conductor provided in the circuit board, and the predetermined direction described above from the portion closer to the second anode terminal than the predetermined portion of the second internal electrode. Along the first cathode terminal and A terminal exposed at an inner side of an exposed portion of the first and second anode terminals with a predetermined interval, the terminal having the predetermined interval with the first ground through hole; A second cathode terminal which is a terminal connected to a conductive material included in the circuit board is connected to a second ground through hole included in the circuit board.

  It is an object of the present invention to provide a capacitor and an electronic device that can improve deficiencies in mounting and characteristics.

Embodiments of the present invention will be described below with reference to the drawings.
(First embodiment)
First, a first embodiment of the present invention will be described.
Here, in order to facilitate understanding of the features of the present invention, a conventional capacitor will be described first. FIG. 1 is an external perspective view of a conventional capacitor and circuit board.
As shown in FIG. 1, a capacitor 2 is mounted on the circuit board 1. The capacitor 2 is a polar capacitor such as an aluminum electrolytic capacitor. The circuit board 1 is provided with pads 3, 4 and 5 which are conductive materials. The first anode terminal 6, the second anode terminal 7 and the cathode terminal 8 are exposed from one surface of the capacitor 2.

  The pad 3 is bonded to the first anode terminal 6 of the capacitor 2 mounted on the circuit board 1. The pad 4 is bonded to the cathode terminal 8 of the capacitor 2 mounted on the circuit board 1. The pad 5 is bonded to the second anode terminal 7 of the capacitor 2 mounted on the circuit board 1.

FIG. 2 is a cross-sectional view of the conventional capacitor 2 and circuit board 1 taken along the line AA ′.
As shown in FIG. 2, the capacitor 2 has a dielectric plate 11 and an internal electrode plate 12 embedded in a mold 13.

  A part of the lower surface of the internal electrode plate 12 is joined to the upper surface of the dielectric plate 11. The area of the internal electrode plate 12 is larger than the area of the dielectric plate 11, and the upper surface of the dielectric plate 11 is joined near the center of the lower surface of the internal electrode plate 12.

  The first anode terminal 6 is joined to one end of the lower surface of the internal electrode plate 12. An end portion of the first anode terminal 6 is exposed from the mold 13 to the outside. The second anode terminal 7 is joined to the other end of the lower surface of the internal electrode plate 12. The end of the second anode terminal 7 is exposed to the outside from the mold 13. The exposure direction of the first anode terminal 6 and the exposure direction of the second anode terminal 7 are the same.

  A cathode terminal 8 is bonded to the entire lower surface of the dielectric plate 11. The end of the cathode terminal 8 is exposed to the outside from the mold 13. The exposed portion of the cathode terminal 8 is located inside the exposed portions of the first anode terminal 6 and the second anode terminal 7. The exposure direction of the cathode terminal 8 is the same as the exposure direction of the first anode terminal 6 and the second anode terminal 7.

As shown in FIG. 2, a GND (ground) layer 14, a first VCC layer 16, and a second VCC layer 17 independent of the first VCC layer 16 are provided inside the circuit board 1. A GND through hole 15 is provided between the GND layer 14 and the pad 4. A first VCC through hole 18 is provided between the first VCC layer 16 and the pad 3, and a second VCC through hole 19 is provided between the second VCC layer 17 and the pad 5.
FIG. 3 is a perspective view showing an electrode exposed surface of a conventional capacitor. As shown in FIG. 3, the first anode terminal 6, the second anode terminal 7 and the cathode terminal 8 are exposed from the capacitor 2.

Next, a capacitor according to the first embodiment of the present invention will be described.
FIG. 4 is a perspective view of the appearance of the capacitor 20 and the circuit board 10 according to the first embodiment of the present invention. FIG. 5 is a cross-sectional view of the capacitor and the circuit board according to the first embodiment of the present invention cut along the line BB ′. Detailed description of the same parts of the capacitor 20 and the circuit board 10 as those of the capacitor 2 and the circuit board 1 will be omitted.

  The capacitor 20 includes a first cathode terminal 21 and a second cathode terminal 22 instead of the cathode terminal 8 as compared with the conventional capacitor 2. The upper surface of the internal electrode plate 23 is bonded to the lower surface of the dielectric plate 11. The first cathode terminal 21 and the second cathode terminal 22 are terminals connected to the internal electrode plate 23. The exposed portions of the first cathode terminal 21 and the second cathode terminal 22 are located inside the exposed portions of the first anode terminal 6 and the second anode terminal 7.

  The circuit board 10 on which the capacitor 20 is mounted includes a pad 24 and a pad 25 instead of the pad 4 as compared with the circuit board 1 on which the conventional capacitor 2 is mounted. The pad 24 is bonded to the first cathode terminal 21 of the capacitor 20 mounted on the circuit board 10. The pad 25 is bonded to the second cathode terminal 22 of the capacitor 20 mounted on the circuit board 10.

  As shown in FIG. 5, the capacitor 20 includes a dielectric plate 11 and internal electrode plates 12 and 23 embedded in a mold 13. A part of the lower surface of the internal electrode plate 12 is joined to the upper surface of the dielectric plate 11. The area of the internal electrode plate 12 is larger than the area of the dielectric plate 11, and the upper surface of the dielectric plate 11 is joined near the center of the lower surface of the internal electrode plate 12.

  Similar to the capacitor 2 shown in FIG. 1, the first anode terminal 6 is joined to one end of the lower surface of the internal electrode plate 12 of the capacitor 20. An end portion of the first anode terminal 6 is exposed from the mold 13 to the outside. The second anode terminal 7 is joined to the other end of the lower surface of the internal electrode plate 12. The end of the second anode terminal 7 is exposed to the outside from the mold 13. The exposure direction of the first anode terminal 6 and the exposure direction of the second anode terminal 7 are the same.

  The first cathode terminal 21 is joined between the center of the lower surface of the internal electrode plate 23 and the end portion of the dielectric plate 11 near the first anode terminal 6. An end portion of the first cathode terminal 21 is exposed to the outside from the mold 13. The second cathode terminal 22 is joined between the center of the lower surface of the internal electrode plate 23 and the end of the dielectric plate 11 near the second anode terminal 7. An end portion of the second cathode terminal 22 is exposed to the outside from the mold 13.

The exposure direction of the first cathode terminal 21 and the exposure direction of the second cathode terminal 22 are the same as those of the first anode terminal 6 and the second anode terminal 7. The first cathode terminal 21 and the second cathode terminal 22 may be different materials as long as they are conductive materials.
An interval of length L1 is provided between the pad 24 and the pad 25 and between the first cathode terminal 21 and the second cathode terminal 22.

  Further, as shown in FIG. 5, a first GND layer 26 and a second GND layer 27 are provided in the circuit board 10 instead of the GND layer 14. The first GND layer 26 and the second GND layer 27 are independent of each other.

  In addition, a first GND through hole 28 is provided between the first GND layer 26 and the pad 24 instead of the single GND through hole 15 in the circuit board 10. A second GND through hole 29 is provided between the second GND layer 27 and the pad 25.

  The distance between the first anode terminal 6 and the first cathode terminal 21 and the distance between the second cathode terminal 22 and the second anode terminal 7 of the capacitor 20 are equal. The distance between the pads 3 and 24 of the circuit board 10 is equal to the distance between the pads 25 and 5.

  FIG. 6 is a perspective view showing an electrode exposed surface of the capacitor according to the first embodiment of the present invention. As shown in FIG. 6, the first anode terminal 6, the second anode terminal 7, the first cathode terminal 21 and the second cathode terminal 22 are exposed from the capacitor 20. In this electrode exposed surface, the area occupied by the exposed portion of the cathode terminal is smaller than that of the electrode exposed surface of the circuit board 1 shown in FIG.

  As described above, in the capacitor 20 according to the first embodiment of the present invention, a part of the exposed portion of the cathode terminal is blocked as compared with the conventional capacitor. As a result, another wiring pattern is formed on the circuit board 10 opposite to the blocked portion when the capacitor 20 is mounted on the circuit board 10, or another through pattern is formed from the portion into the circuit board 10. Halls can be provided.

  Further, a plurality of cathode terminals are exposed to the outside of the capacitor 20. When this capacitor is mounted on a circuit board provided with a GND layer or a GND through hole for each cathode terminal, the impedance characteristic in the high frequency region is the impedance characteristic in the high frequency region when one exposed cathode terminal is mounted on the circuit substrate. Improved compared to

  As an example of mounting the capacitor 20, the second VCC layer 17 and the second GND layer 27 of the circuit board 10 are connected to a power source, and the first VCC layer 16 and the first GND layer 26 are connected to an electronic component operating at a high frequency such as a CPU. .

  In this case, the second VCC layer 17, the second VCC through hole 19, the pad 5, the second anode terminal 7, the internal electrode plate 12, the first anode terminal 6, the pad 3, the first VCC through hole 18 and the first VCC layer 16 are electrically connected. The serially connected line becomes a part of the power supply line connecting the positive terminal of the power supply and the electronic component. Also, the first GND layer 26, the first GND through hole 28, the pad 24, the first cathode terminal 21, the internal electrode plate 23, the second cathode terminal 22, the pad 25, the second GND through hole 29, and the second GND layer 27 are electrically connected. The line connected in series becomes a part of the power supply line connecting the electronic component and the negative terminal of the power supply.

  In this case, since the influence of the inductance of the terminal portion is reduced as compared with the conventional case where a capacitor is connected between the power supply lines, the impedance characteristic in the high frequency region is improved.

The circuit board 10 is accommodated in an electronic device such as a notebook PC. FIG. 7 is a perspective view showing an example of the appearance of the notebook PC 50 that houses the circuit board 10 mounted with the capacitor 20 according to the first embodiment of the present invention.
As shown in FIG. 7, the notebook PC 50 includes a housing 51, a keyboard 52, and a display 53. The housing 51 accommodates the circuit board 10.

  In addition, since the distance between the first anode terminal 6 and the first cathode terminal 21 of the capacitor 20 and the distance between the second cathode terminal 22 and the second anode terminal 7 are equal, this is the GND layer or the GND through hole. Impedance characteristics in the high frequency region when mounted on a circuit board provided for each cathode terminal are improved as compared with the impedance characteristics when the distances vary.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. FIG. 8 is an external perspective view of the capacitor 30 and the circuit board 40 according to the second embodiment of the present invention. FIG. 9 is a cross-sectional view of the capacitor 30 and the circuit board 40 according to the second embodiment of the present invention cut along the line CC ′. Of the capacitor 30 and the circuit board 40, detailed description of the same parts as the capacitor 20 and the circuit board 10 used in the first embodiment will be omitted.

  The capacitor 30 includes a first cathode terminal 31 and a second cathode terminal 32 instead of the first cathode terminal 21 and the second cathode terminal 22 as compared with the capacitor 20 used in the first embodiment. The upper surface of the internal electrode plate 33 is bonded to the lower surface of the dielectric plate 11. The first cathode terminal 31 and the second cathode terminal 32 are terminals connected to the internal electrode plate 33.

  The circuit board 40 on which the capacitor 30 is mounted includes pads 34 and 35 instead of the pads 24 and 25 as compared with the circuit board 10 used in the first embodiment.

  The pad 34 is bonded to the first cathode terminal 31 of the capacitor 30 mounted on the circuit board 40. The pad 35 is bonded to the second cathode terminal 32 of the capacitor 30 mounted on the circuit board 40.

  As shown in FIG. 9, the capacitor 30 includes a dielectric plate 11 and internal electrode plates 12 and 33 embedded in a mold 13. A first cathode terminal 31 is joined to an end of the lower surface of the internal electrode plate 33 near the first anode terminal 6. An end portion of the first cathode terminal 31 is exposed to the outside from the mold 13. The second cathode terminal 32 is joined to the end of the lower surface of the internal electrode plate 33 near the second anode terminal 7. An end portion of the second cathode terminal 32 is exposed to the outside from the mold 13.

  The exposure direction of the first cathode terminal 31 and the exposure direction of the second cathode terminal 32 are the same as those of the first anode terminal 6 and the second anode terminal 7. The exposure direction of the first cathode terminal 31 and the exposure direction of the second cathode terminal 32 are the same as those of the first anode terminal 6 and the second anode terminal 7. The first cathode terminal 31 and the second cathode terminal 32 may be different materials as long as they are conductive materials.

  A distance of L2 is provided between the pad 34 and the pad 35 and between the first cathode terminal 31 and the second cathode terminal 32. The length L2 is longer than the length L1 described in the first embodiment.

  As shown in FIG. 9, a first GND layer 36 and a second GND layer 37 are provided inside the circuit board 40 instead of the first GND layer 26 and the second GND layer 27 described in the first embodiment.

  Further, instead of providing the first GND through hole 28 and the second GND through hole 29 in the circuit board 40, a first GND through hole 38 is provided between the first GND layer 36 and the pad 34. A second GND through hole 39 is provided between the second GND layer 37 and the pad 35.

  The distance between the first anode terminal 6 and the first cathode terminal 31 of the capacitor 30 and the distance between the second cathode terminal 32 and the second anode terminal 7 are equal. Further, the distance between the pads 3 and 34 of the circuit board 40 is equal to the distance between the pads 35 and 5.

  As described above, in the capacitor 30 according to the second embodiment of the present invention, the distance between each exposed portion of the cathode terminal is longer than that of the capacitor 20 used in the first embodiment. When this capacitor is mounted on a circuit board in which a GND layer or a GND through hole is provided for each cathode terminal, the impedance characteristic in a high frequency region is improved as compared with the impedance characteristic of the capacitor 20 described in the first embodiment. .

  Further, as described above, when the distance between the first anode terminal 6 and the first cathode terminal 31 of the capacitor 30 and the distance between the second cathode terminal 32 and the second anode terminal 7 are equal, the GND of the capacitor 20 is set. Impedance characteristics in the high frequency range when the layer or the GND through hole is mounted on a circuit board provided for each cathode terminal are improved as compared with the impedance characteristics when the distances vary.

  FIG. 10 is a graph showing the frequency characteristics of the impedance of the capacitor according to the first embodiment of the present invention, the frequency characteristics of the impedance of the capacitor according to the second embodiment, and the frequency characteristics of the impedance of the conventional capacitor. It is.

  “Product D” shown in FIG. 10 indicates a product incorporating the capacitor 20 according to the first embodiment described above. “Product E” shown in FIG. 10 is a product incorporating the capacitor 30 according to the second embodiment described above.

  As shown in FIG. 10, the impedance at each frequency of the product incorporating the capacitor 20 used in the first embodiment is generally lower than the impedance at each frequency of the product incorporating the conventional capacitor. The impedance at each frequency incorporating the capacitor 30 used in the second embodiment is generally lower than the impedance at each frequency of the capacitor 20 used in the first embodiment.

  That is, the capacitor described in the first and second embodiments correctly follows fluctuations in the power supply voltage of the device when used with electronic components that operate at a high frequency such as a CPU of a personal computer. Therefore, compared with the case where a conventional capacitor is used, the power supply voltage of the device is stabilized, so that the operation stability can be improved.

  In the embodiment described above, it has been described that the two cathode terminals are exposed from the mold 13 to the outside. However, the present invention is not limited thereto, and for example, three cathode terminals may be exposed from the mold 13 to the outside. In this case, a VCC layer, a GND layer, and various through holes corresponding to the number of cathode terminals may be provided on the circuit board side on which the capacitor is mounted.

  In the embodiment described above, the dielectric plate is sandwiched between the anode electrode and the cathode electrode. However, the present invention is not limited to this. For example, a rod-shaped electrode for the anode is wrapped with a dielectric layer, and this dielectric layer May be wrapped with an electrode layer for the cathode. In this case, anode terminals may be provided at both ends of the rod-shaped electrode for anode to expose them to the outside, and a plurality of cathode terminals may be attached to the electrode layer for cathode to expose them to the outside.

  The present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Moreover, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be omitted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

The perspective view of the external appearance of the conventional capacitor | condenser and a circuit board. Sectional drawing at the time of cut | disconnecting the conventional capacitor | condenser and circuit board along the AA 'line. The perspective view which shows the electrode exposed surface of the conventional capacitor | condenser. 1 is a perspective view of the appearance of a capacitor and a circuit board according to a first embodiment of the present invention. Sectional drawing at the time of cut | disconnecting the capacitor | condenser and circuit board according to the 1st Embodiment of this invention along a BB 'line | wire. The perspective view which shows the electrode exposure surface of the capacitor | condenser according to the 1st Embodiment of this invention. The perspective view which shows an example of the external appearance of notebook PC which accommodated the circuit board 10 which mounted the capacitor | condenser 20 according to the 1st Embodiment of this invention. The perspective view of the appearance of a capacitor and a circuit board according to a second embodiment of the present invention. Sectional drawing at the time of cut | disconnecting the capacitor | condenser and circuit board according to the 2nd Embodiment of this invention along CC 'line. The figure which shows the frequency characteristic of the impedance of the capacitor | condenser according to 1st Embodiment of this invention, the frequency characteristic of the impedance of the capacitor | condenser according to 2nd Embodiment, and the frequency characteristic of the impedance of the conventional capacitor | condenser as a graph.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,10,40 ... Circuit board, 2, 20, 30 ... Capacitor, 3, 4, 5, 24, 25, 34, 35 ... Pad, 6 ... 1st anode terminal, 7 ... 2nd anode terminal, 8 ... Cathode Terminals 11 ... Dielectric plate 12, 23, 33 ... Internal electrode plate, 13 ... Mold, 14 ... GND layer, 15 ... GND through hole, 16, 17 ... VCC layer, 18 ... First VCC through hole, 19 ... First 2 VCC through hole, 21, 31, first cathode terminal, 22, 32, second cathode terminal, 26, 36, first GND layer, 27, 37, second GND layer, 28, 38, first GND through hole, 29, 39 2nd GND through hole, 50 ... notebook PC, 51 ... housing, 52 ... keyboard, 53 ... display.

Claims (4)

A first anode terminal exposed along a predetermined direction from one end of the first internal electrode joined to one side of the dielectric;
A second anode terminal exposed from the other end of the first internal electrode along the predetermined direction;
The first and second anode terminals are connected along the predetermined direction from a predetermined portion of a second internal electrode connected to the other side of the dielectric and independent of the first internal electrode. A first cathode terminal that is exposed to the inside of the exposed portion and is connected to a conductive material included in the circuit board connected to a first ground through hole included in the circuit board;
The first internal electrode has a predetermined distance from the first cathode terminal along the predetermined direction from a portion closer to the second anode terminal than the predetermined portion of the second internal electrode. A terminal exposed to the inside of the exposed portion of the first and second anode terminals, the second ground through hole provided in the circuit board having the predetermined distance from the first ground through hole; A capacitor comprising: a second cathode terminal which is a terminal connected to a conductor provided in the circuit board. The circuit board further includes a first ground layer that is continuous with the first ground through hole, and a second ground layer that is continuous with the second ground through hole and independent of the first ground layer. The capacitor according to claim 1. The circuit board includes a first conductive material, a first VCC through hole connected to the first conductive material, a first VCC layer connected to the first VCC through hole, and a second conductive material. A second VCC through hole connected to the second conductive material, a second VCC layer connected to the second VCC through hole and independent of the first VCC layer, and the first ground through hole. A first ground layer connected to the second ground layer, and a second ground layer connected to the second ground through hole and independent of the first ground layer,
The first anode terminal is a terminal connected to the first conductor,
The capacitor according to claim 1, wherein the second anode terminal is a terminal connected to the second conductive material.   An electronic apparatus comprising a circuit board on which the capacitor according to any one of claims 1 to 3 is mounted.

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