JPH0745950Y2 - Chip type monolithic ceramic capacitor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention relates to a chip type multilayer ceramic capacitor used in general electronic equipment.

Conventional Technology Conventionally, this type of chip-type multilayer ceramic capacitor is
Internal electrodes 2 (2a, 2b, 2c, ...) that are alternately laminated inside the dielectric ceramic 1 have a structure as shown in FIGS. 4 (A) and (B).
..) is alternately drawn to both end surfaces of the dielectric ceramic 1 and the external electrodes 3 are provided so that the internal electrodes 2 are connected in parallel.

Problems to be Solved by the Invention In such a conventional configuration, the capacitance of the capacitor is formed between the internal electrodes 2a, 2b, 2c, .. 4A and 4B, the capacitance between the lands 5a and 5b of the printed circuit board 4 is the lowest layer of the capacitor in addition to the capacitance of the capacitor body. The stray capacitance generated between the internal electrode 2a located at the point and the land portion 5a is added, and the electrostatic capacitance between the land portions 5a and 5b after mounting the capacitor becomes larger than the capacitance of the capacitor. There was a problem that the capacity fluctuated.

In particular, when the electrostatic capacitance is small, the absolute value of the stray capacitance becomes large and cannot be ignored in the circuit.

Further, when the product has the same width (W) and thickness (T), the internal electrodes 2a, 2b, 2c have the same dimensions as shown in FIGS. 4 (A) and 4 (B). The main surface portion is mounted parallel to the lands 5a and 5b of the printed circuit board, or the main surface portion is vertical as shown in FIGS. 5 (A) and 5 (B). Therefore, there is a problem in that the capacitance changes. In FIGS. 4 and 5, 6 is a solder for attachment.

The present invention solves such a problem and prevents stray capacitance between the land portion of the printed circuit board and the internal electrode of the chip-type monolithic ceramic capacitor even when the mounting direction is changed to prevent electrostatic discharge. The purpose is to provide a product whose capacity does not fluctuate.

Means for Solving the Problem In order to solve this problem, the present invention provides a dielectric material on the outer peripheral portion of an internal electrode laminated inside a dielectric ceramic so as not to be connected to an internal electrode and an external electrode. A shield electrode is provided via a porcelain, and the outer periphery of this shield electrode is covered with an insulating material.

Operation With this configuration, when the chip type monolithic ceramic capacitor is mounted on the printed circuit board, the land part of the printed circuit board and the internal electrode of the capacitor are separated by the shield electrode provided on the outer peripheral part of the internal electrode. Therefore, the generation of stray capacitance between the land portion of the printed circuit board and the internal electrode of the capacitor is prevented, and the problem that the electrostatic capacitance fluctuates is solved.

Embodiment FIG. 1 is a perspective view showing a partial cross-sectional view of a chip type monolithic ceramic capacitor according to an embodiment of the present invention with a part of an insulating sheath removed. In FIG. 1, 11 is a dielectric ceramic,
A plurality of internal electrodes 12 are provided inside the dielectric porcelain 11 so that one of them reaches the different end faces alternately, and 13 of the dielectric porcelain 11 so that the internal electrodes 12 are connected in parallel. External electrodes provided on both end face portions, 14 are shield electrodes provided on the outer peripheral portion of the external electrode 13 via the dielectric ceramic 11, and are not connected to the internal electrode 12 and the external electrode 13. ing. Reference numeral 15 denotes an insulating sheath made of an insulating material provided on the outer peripheral portion of the shield electrode 14 for insulation.

2 (A) and 2 (B) are cross-sectional views in a length direction and a width direction in which the chip type monolithic ceramic capacitor of the above-described embodiment is mounted on a printed circuit board.
The main surface portions of 12 (12a, 12b, 12c, ...) Are located in parallel with the land portions 17a, 17b of the printed board 16. In FIG. 2, the capacitance of the capacitor is the capacitance formed by the internal electrodes 12a and 12b, the capacitance formed by the internal electrodes 12b and 12c, and the like, but the shield electrode 14 is not provided. In the conventional configuration, stray capacitance is also generated between the land portion 17a and the internal electrode 12a, but in the present embodiment, since the shield electrode 14 is between the land portion 17a and the internal electrode 12a, the land portion 17a
Stray capacitance is generated between a and the shield electrode 14. However, since the shield electrode 14 is not connected to the internal electrode 12a, it does not affect the capacitance of the capacitor.

FIGS. 3 (A) and 3 (B) are sectional views in the length direction and the width direction of the state where the chip type monolithic ceramic capacitor of the present example is mounted on the printed circuit board, and shows the internal electrode 12 The main surface portion is positioned perpendicular to the land portions 17a and 17b of the printed board 16. In FIG. 3, the shield electrode 14 is provided between the internal electrode 12 and the lands 17a and 17b, and is not affected by the stray capacitance as described above. As described above, by providing the shield electrode 14 on the outer peripheral portion of the internal electrode 12, it is possible to obtain the one without the influence of the stray capacitance due to the directivity of the capacitor, and it is possible to solve the problem that the capacitance varies. it can.

In FIG. 2 and FIG. 3, 18 is a solder for attachment.

As described above, according to the present invention, by providing the shield electrode on the outer peripheral portion of the internal electrode of the capacitor so as not to be connected to the internal electrode and the external electrode, the internal electrode of the capacitor and the land portion of the printed circuit board are formed. It is possible to improve the influence of the stray capacitance during the period and to provide a product in which the capacitance does not fluctuate.

[Brief description of drawings]

FIG. 1 is a perspective view showing a partial cross-sectional view of a chip type monolithic ceramic capacitor according to an embodiment of the present invention with a part of an insulating sheath removed, and FIGS. 2 (A) and 2 (B) show the same capacitor on a printed circuit board. Sectional views in the length direction and the width direction in the mounted state, and FIGS. 3 (A) and 3 (B) are cross sections in the length direction and the width direction in which the capacitor is mounted on the printed circuit board by changing the mounting direction. FIGS. 4 (A) and 4 (B) are cross-sectional views in a length direction and a width direction in which a conventional chip-type monolithic ceramic capacitor is mounted on a printed circuit board, and FIGS.
FIG. 6B is a cross-sectional view in the length direction and the width direction in which the same capacitor is mounted on a printed circuit board by changing the mounting direction. 11 ... Dielectric porcelain, 12,12a, 12b, 12c ... Internal electrodes, 13 ...
… External electrode, 14 …… Shield electrode, 15 …… Insulation sheath, 16
…… Printed circuit board, 17,17a, 17b …… Land part, 18 …… Solder.

Claims (1)

[Scope of utility model registration request] 1. A plurality of internal electrodes are provided inside a dielectric porcelain, a part of the internal electrodes are alternately drawn out to different end face portions of the dielectric porcelain, and the dielectric is connected in parallel. An external electrode is provided on the end surface of the porcelain, and a shield electrode is provided on the outer peripheral portion of the internal electrode via a dielectric ceramic so as not to be connected to the internal electrode and the external electrode. An insulating material is provided on the outer peripheral portion of the shield electrode. Chip-type monolithic ceramic capacitor with exterior.