JP2007109817A - Capacitor and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve failure in characteristic when a capacitor is mounted on a circuit board. <P>SOLUTION: A pad 3 for connecting a first anode terminal 6 of a capacitor 30, a pad 5 for connecting a second anode terminal 7, and pads 31, 32 for connecting a cathode terminal 8, are respectively provided within a circuit board 10. A first VCC layer 16, a second VCC layer 17, a first GND layer 33, and a second GND layer 34, are also provided within the circuit board 10. A first VCC through-hole 18 is provided between the first VCC layer 16 and the pad 3. A second VCC through-hole 19 is also provided between the second VCC layer 17 and the pad 5. A first GND through-hole 35 is provided between the first GND layer 33 and the pad 31. Moreover, a second GND through-hole 36 is provided between the second GND layer 34 and the pad 32. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a circuit board on which a capacitor used for a high-frequency electronic circuit is mounted and an electronic apparatus.

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 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.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a circuit board and an electronic device that can improve deficiencies in characteristics when a capacitor is mounted.

  A circuit board according to the present invention includes a capacitor and a wiring board on which the capacitor is mounted. The capacitor includes a dielectric, an internal electrode joined to one side of the dielectric, and one end of the internal electrode. A first anode terminal exposed along a predetermined direction from the first portion, a second anode terminal exposed along the predetermined direction from the other end of the internal electrode, and the other side of the dielectric And a cathode terminal exposed inside the exposed portions of the first and second anode terminals along the predetermined direction, and the wiring board is electrically connected to the first anode terminal of the capacitor. A first through hole for connecting to the first through hole, a first conductor layer connected to the first through hole, and a second through for electrically connecting to the second anode terminal of the capacitor The hole and this second through hole A second conductive layer, a third through hole for electrical connection with a predetermined portion of the cathode terminal of the capacitor, and a third conductive layer connected to the third through hole A fourth through hole having a predetermined distance from the third through hole and electrically connected to a portion closer to the second anode terminal than the predetermined portion of the cathode terminal of the capacitor; And a fourth conductor layer connected to the fourth through hole.

  ADVANTAGE OF THE INVENTION According to this invention, the defect of the characteristic at the time of mounting a capacitor | condenser on a circuit board can be improved.

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 a perspective view of the appearance of a conventional capacitor and a circuit board on which the capacitor is mounted.

  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 conductors. 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 4 is provided inside the pads 3 and 5 provided on the circuit board 1.

  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 length of the internal electrode plate 12 is longer than the length 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 layer 14, a first VCC layer 16, and a second VCC layer 17, which are conductors, 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.

  The first VCC layer 16 and the second VCC layer 17 are independent of each other and are provided at the same height in the circuit board 1. The GND layer 14 is provided below the first VCC layer 16 and the second VCC layer 17 in the circuit board 1. The GND through hole 15 is provided between the first VCC through hole 18 and the second VCC through hole 19 in the circuit board 1.

Next, a circuit board according to the first embodiment of the present invention will be described.
The circuit board 10 according to the first embodiment of the present invention is accommodated in an electronic device such as a notebook PC. FIG. 3 is a perspective view showing an example of the appearance of the notebook PC 20 that houses the circuit board 10 according to the first embodiment of the present invention.
As shown in FIG. 3, the notebook PC 20 includes a housing 21, a keyboard 22, and a display 23. The housing 21 accommodates the circuit board 10.

  FIG. 4 is a perspective view of the external appearance of the circuit board 10 and the capacitor 30 mounted thereon according to the first embodiment of the present invention. FIG. 5 is a cross-sectional view of the circuit board 10 and the capacitor 30 mounted thereon according to the first embodiment of the present invention cut along the line BB ′. Detailed description of the same parts of the circuit board 10 as those of the conventional circuit board 1 is omitted.

  The configuration of the capacitor 30 is the same as that of the conventional capacitor 2. The circuit board 10 on which the capacitor 30 is mounted includes pads 31 and 32 instead of the pad 4 as compared with the circuit board 1 on which the conventional capacitor 2 is mounted.

  The pad 31 is joined to the end portion of the lower surface of the exposed portion of the cathode terminal 8 of the capacitor 30 mounted on the circuit board 10 near the first anode terminal 6. The pad 32 is bonded to an end portion of the lower surface of the exposed portion of the cathode terminal 8 of the capacitor 30 mounted on the circuit board 10 near the second anode terminal 7.

  As shown in FIG. 5, a first GND layer 33 and a second GND layer 34 are provided inside the circuit board 10 instead of the single GND layer 14 provided in the conventional circuit board 1. The first GND layer 33 and the second GND layer 34 are independent and are provided at the same height in the circuit board 10. The first GND layer 33 is provided below the first VCC layer 16 in the circuit board 10, and the second GND layer 34 is provided below the second VCC layer 17 in the circuit board 10.

  In addition, a first GND through hole 35 and a second GND through hole 36 are provided inside the circuit board 10 instead of the single GND through hole 15 provided in the conventional circuit board 1.

  The first GND through hole 35 electrically connects one location between the end of the pad 31 near the pad 3 and the end near the pad 32 to one location of the first GND layer 33. The second GND through hole 36 electrically connects one place between the end portion of the pad 32 near the pad 31 and the end portion near the pad 5 and one place of the second GND layer 34.

The first GND through hole 35 is provided near the first VCC through hole 18 between the first VCC through hole 18 and the second VCC through hole 19 in the circuit board 10. The second GND through hole 36 is provided near the second VCC through hole 19 between the first VCC through hole 18 and the second VCC through hole 19 in the circuit board 10.
An interval of a length L1 is provided between the first GND through hole 35 and the second GND through hole 36 of the circuit board 10.

  The distance between the first anode terminal 6 and the cathode terminal 8 of the capacitor 30 and the distance between the cathode terminal 8 and the second anode terminal 7 are equal. The distance between the pads 3 and 31 of the circuit board 10 is equal to the distance between the pads 32 and 5. Further, the distance between the first VCC through hole 18 and the first GND through hole 35 in the circuit board 10 is equal to the distance between the second VCC through hole 19 and the second GND through hole 36.

  As described above, there are a plurality of pads and through holes on the circuit board 10 side for connection to the cathode terminal of the capacitor according to the first embodiment of the present invention. The impedance characteristic in the high frequency region when the capacitor is mounted on such a circuit board is the impedance characteristic in the high frequency region when there is one through hole and one pad on the circuit board side for connection to the cathode terminal of the capacitor. Compared with improvement.

  As an example of mounting the capacitor 30, the second VCC layer 17 and the second GND layer 34 of the circuit board 10 are connected to a power source, and the first VCC layer 16 and the first GND layer 33 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 the power sources. It becomes a part of the power line connecting the plus terminal and the electronic component. Further, the first GND layer 33, the first GND through hole 35, the pad 31, the cathode terminal 8, the pad 32, the second GND through hole 36, and the second GND layer 34 become 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 of the capacitor is reduced as compared with the conventional case where the capacitor is connected between the power supply lines, the impedance characteristic in the high frequency region is improved.

  Further, when the distance between the first VCC through hole 18 and the first GND through hole 35 of the circuit board 10 is equal to the distance between the second VCC through hole 19 and the second GND through hole 36, the circuit board 10 Impedance characteristics in a high frequency region when a capacitor is mounted are improved as compared with the impedance characteristics in the case where there is variation in distance as described above.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. FIG. 6 is a perspective view of the external appearance of the circuit board 50 and the capacitor 40 mounted thereon according to the second embodiment of the present invention. FIG. 7 is a cross-sectional view of the capacitor 40 and the circuit board 50 according to the second embodiment of the present invention cut along the line CC ′. A detailed description of the circuit board 50 that is the same as the circuit board 10 used in the first embodiment is omitted.

  The configuration of the capacitor 40 according to the second embodiment of the present invention is the same as the configuration of the capacitor 30 used in the first embodiment. The circuit board 50 on which the capacitor 40 is mounted includes pads 41 and 42 instead of the pads 31 and 32 as compared with the circuit board 10 used in the first embodiment.

  The pad 41 is joined to the end portion of the lower surface of the exposed portion of the cathode terminal 8 of the capacitor 40 mounted on the circuit board 50 near the first anode terminal 6. The pad 42 is bonded to an end portion of the lower surface of the exposed portion of the cathode terminal 8 of the capacitor 40 mounted on the circuit board 50 near the second anode terminal 7.

  As shown in FIG. 7, a first GND layer 43 and a second GND layer 44 are provided in the circuit board 50 instead of the first GND layer 33 and the second GND layer 34 described in the first embodiment.

  The first GND layer 43 and the second GND layer 44 are independent of each other and are provided at the same height in the circuit board 50. The first GND layer 43 is provided below the first VCC layer 16 in the circuit board 50, and the second GND layer 44 is provided below the second VCC layer 17 in the circuit board 50.

  In addition, instead of the first GND through hole 35 and the second GND through hole 36, a first GND through hole 45 and a second GND through hole 46 are provided inside the circuit board 50.

  The first GND through hole 45 electrically connects an end portion of the pad 41 near the pad 3 and one place of the first GND layer 43. The second GND through hole 46 electrically connects an end portion of the pad 42 near the pad 5 and one place of the second GND layer 44.

  The first GND through hole 45 is provided in the circuit board 50 at a location near the first VCC through hole 18 between the first VCC through hole 18 and the second VCC through hole 19. The second GND through hole 46 is provided in the circuit board 50 at a location near the second VCC through hole 19 between the first VCC through hole 18 and the second VCC through hole 19.

  An interval of a length L2 is provided between the first through hole 45 and the second GND through hole 46 in the circuit board 50. The length L2 is longer than the length L1 described in the first embodiment.

  The distance between the first anode terminal 6 and the cathode terminal 8 of the capacitor 40 and the distance between the cathode terminal 8 and the second anode terminal 7 are equal. The distance between the pads 3 and 41 of the circuit board 50 is equal to the distance between the pads 42 and 5.

  The distance between the first VCC through hole 18 and the first GND through hole 45 in the circuit board 50 is equal to the distance between the second VCC through hole 19 and the second GND through hole 46.

  As described above, the circuit board 50 on which the capacitor 40 according to the second embodiment of the present invention is mounted has a space between the GND through holes as compared with the circuit board 10 on which the capacitor 30 used in the first embodiment is mounted. The distance is long. The impedance characteristic in the high frequency region when the capacitor is mounted on the circuit board is improved as compared with the impedance characteristic when the capacitor is mounted on the circuit board described in the first embodiment.

  The distance between the first VCC through hole 18 and the first GND through hole 45 in the circuit board 50 is equal to the distance between the second VCC through hole 19 and the second GND through hole 46. The impedance characteristic in the high frequency region when the capacitor is mounted on the circuit board 50 is improved as compared with the impedance characteristic when the distance varies as described above.

  FIG. 8 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.

  The “conventional product” shown in FIG. 8 indicates a product incorporating the circuit board 1 on which the above-described conventional capacitor 2 is mounted. “Product D” shown in FIG. 8 indicates a product incorporating the circuit board 10 on which the capacitor 30 according to the first embodiment is mounted. Further, “product E” shown in FIG. 8 indicates a product in which the circuit board 50 on which the capacitor 40 according to the second embodiment is mounted is incorporated.

  As shown in FIG. 8, the impedance at each frequency of the product incorporating the circuit board 10 on which the capacitor 30 used in the first embodiment is mounted is the frequency at each frequency of the product incorporating the circuit board 1 on which the conventional capacitor 2 is mounted. Generally low compared to impedance. The impedance at each frequency incorporating the circuit board 50 on which the capacitor 40 used in the second embodiment is mounted is generally lower than the impedance at each frequency of the circuit board 10 on which the capacitor 30 used in the first embodiment is mounted. .

  An apparatus using the capacitor described in the first and second embodiments together with an electronic component operating at a high frequency such as a CPU of a personal computer correctly follows the fluctuation of the operating current and stabilizes the power supply voltage of the electronic component. Will have. Therefore, the stability of the operation of the device can be improved.

  In the embodiment described above, the capacitor has a structure in which a dielectric plate is sandwiched between an anode electrode and a cathode electrode. However, the present invention is not limited to this. For example, a rod-shaped electrode for an anode is wrapped with a dielectric layer. The body layer may be wrapped with an electrode layer for a cathode. In this case, anode terminals may be provided on both ends of the anode rod-shaped electrode to expose them to the outside, and the cathode terminals may be attached to the cathode electrode layer 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 an example of the external appearance of the notebook PC which accommodated the circuit board which mounted the capacitor | condenser according to the 1st Embodiment of this invention. The perspective view of the external appearance of the circuit board according to the 1st Embodiment of this invention, and the capacitor | condenser mounted in this. 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 of the external appearance of the circuit board according to the 2nd Embodiment of this invention, and the capacitor | condenser mounted in this. 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 1,10,50 ... Circuit board, 30, 40 ... Capacitor, 3, 4, 5, 31, 32, 41, 42 ... Pad, 6 ... 1st anode terminal, 7 ... 2nd anode terminal, 8 ... Cathode terminal, DESCRIPTION OF SYMBOLS 11 ... Dielectric board, 12 ... Internal electrode plate, 13 ... Mold, 14 ... GND layer, 15 ... GND through hole, 16 ... 1st VCC layer, 17 ... 2nd VCC layer, 18 ... 1st VCC through hole, 19 ... 2nd VCC Through hole, 20 ... notebook PC, 21 ... casing, 22 ... keyboard, 23 ... display, 33, 43 ... first GND layer, 34, 44 ... second GND layer, 35, 45 ... first GND through hole, 36, 46 ... Second GND through hole.

Claims (4)

A circuit board comprising a capacitor and a wiring board on which the capacitor is mounted,
The capacitor is
A dielectric,
An internal electrode joined to one side of the dielectric;
A first anode terminal exposed along a predetermined direction from one end of the internal electrode;
A second anode terminal exposed along the predetermined direction from the other end of the internal electrode;
A cathode terminal connected to the other side of the dielectric and exposed inside the exposed portion of the first and second anode terminals along the predetermined direction;
The wiring board is
A first through hole for electrically connecting to the first anode terminal of the capacitor;
A first conductor layer connected to the first through hole;
A second through hole for electrically connecting to a second anode terminal of the capacitor;
A second conductor layer connected to the second through hole;
A third through hole for electrically connecting to a predetermined portion of the cathode terminal of the capacitor;
A third conductor layer connected to the third through hole;
A fourth through hole having a predetermined distance from the third through hole and electrically connected to a portion closer to the second anode terminal than the predetermined portion of the cathode terminal of the capacitor;
A circuit board comprising: a fourth conductor layer connected to the fourth through hole. The third through hole is provided for electrical connection with an end portion of the cathode terminal of the capacitor close to the first anode terminal;
2. The circuit board according to claim 1, wherein the fourth through hole is provided to be electrically connected to an end portion of the cathode terminal of the capacitor close to the second anode terminal. 3.   The distance between the first through hole and the third through hole is equal to the distance between the second through hole and the fourth through hole. Circuit board.   An electronic apparatus comprising the circuit board according to claim 1.

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