JP2600543Y2 - External electrode structure - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an external electrode structure of a surface mount type electronic component, and more particularly to an external electrode structure provided with a short circuit preventing means.

[0002]

2. Description of the Related Art An electronic component is formed in a square or rectangular plate shape to be a surface mount type, and a plurality of external electrodes for connecting to an external circuit are baked along the edge thereof at regular intervals in a film shape. Plating is widely practiced. FIG. 1 is a perspective view showing an example of a general surface-mount type electronic component.
A small electronic component 1 such as a multilayer resistor, the outer surface 3 of which is formed of an electrically insulating dielectric, magnetic or non-magnetic ferrite, ceramic, or the like, and a plurality of external terminals connected to the lead conductor of the internal circuit on the long sides facing each other. The electrodes 3, 3,... Are formed.

The external electrodes are usually formed by an electroplating method. However, since the outer surface 2 of the electronic component 1 is electrically insulating, the upper surface of the electronic component is firstly provided with a conductive paste (Ag powder paste or the like) as a base. To the end face and then to the lower face, and bake them in a strip shape, and form several electroplating layers (for example, successive layers of Cu, Ni and Sn layers) thereon by barrel plating or the like. In this way, an external electrode including the upper and lower folded electrode portions 5 and the end surface electrode portion 7 on the end surface is formed.

[0004]

[Problem to be solved by the invention] With the miniaturization of electronic circuits, there is an increasing demand for miniaturization of electronic components. To do so, external electrodes must be arranged close to each other. In the conventional external electrode structure of an electronic component, a problem of a short circuit occurs. This will be described with reference to FIGS. 2 and 3. If the conductive paste layer 9 is baked in a square or rectangular shape, the current density increases at the corners of the conductive paste layer during plating. In each of the folded electrode portion 5 and the end surface electrode portion 7 on the end surface in FIG. 3, the spread portions 11 of the plating are formed at the upper and lower ends, and solder such as flow solder or cream solder is applied in a state where the external electrodes are close to each other. If applied, a short circuit may occur.

[0005]

According to the present invention, there is provided a surface-mount type electronic component in which a plurality of strip electrodes for external connection formed over an end face and at least one of upper and lower faces are arranged close to each other. Comprises a conductive paste layer and an electroplating layer formed on the surface thereof, wherein the conductive paste layer
Is Oite the surfaces, the width viewed in the arrangement direction thereto
The conventional short-circuit problem is solved by the external electrode structure of the electronic component, wherein the width is formed narrow at both ends in the direction perpendicular to the width and wide at the middle part. It is preferable that the width of each part of the conductive paste layer is defined so that the width of the finished electroplated layer is substantially constant so that the electrodes are as parallel as possible so as not to cause a short circuit even when they are close to each other.

An embodiment of the present invention will be described below in detail with reference to FIGS.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 An electronic component to which the present invention is applied is the same as a conventional one, and has, for example, the structure shown in FIG. The external electrodes 3, 3
The details of the arrangement are omitted because the arrangement is the same. FIG. 4 is a plan view or a bottom view of a part of the electronic component, in which an electrode turning portion 5 on the upper surface or the lower surface of one external electrode is shown. FIG. 5 is a front view of the same portion, and shows the electrode turning portion 7 on the end face. According to the present invention, the four corners of the baked conductive paste layer 9 are each straightly obliquely deviated, forming a polygon having a narrow width at the upper and lower ends and a wide width at the middle. When an electroplating layer is formed on the conductive paste layer 9 by a barrel plating method or the like in the same manner as before, the electroplated layer is not only formed uniformly on the conductive paste layer 9 but also spreads out from the corners. The part 13 results. If the width of the corner of the conductive paste layer 9 is appropriately selected in consideration of the spread in the electroplating, the finished width of the external electrode after the electroplating can be made substantially constant.

Embodiment 2 FIG. 6 is a plan view or a bottom view of a part of an electronic component according to another embodiment, in which an electrode turning portion 5 on the upper surface or the lower surface of one external electrode is shown. FIG. 7 is a front view of the same portion, and shows the electrode turn-up portion 7 on the end face. According to the present invention, the four corners of the baked conductive paste layer 9 have curved shapes, and have a barrel shape as a whole.
When an electroplating layer is formed on the conductive paste layer 9 by a barrel plating method or the like in the same manner as before, the electroplating layer is not only formed uniformly on the conductive paste layer 9 but also spreads out from the corners. The part 13 results. If the width of the corner of the conductive paste layer 9 is appropriately selected in consideration of the spread in the electroplating, the finished width of the external electrode after the electroplating can be made substantially constant.

[0008]

According to the present invention, even when the external electrodes are arranged close to each other when the electronic component is miniaturized, the width of the portion including the corners of the conductive paste layer where the current density becomes large becomes larger than that of the central portion. By making the width narrower, the plating finish width of the external electrode can be made substantially constant, and there is no possibility that a short circuit will occur when solder is applied.

[Brief description of the drawings]

FIG. 1 is a perspective view of an electronic component to which the present invention is applied.

FIG. 2 is a plan view showing a conventional external electrode structure.

FIG. 3 is a front view showing a conventional external electrode structure.

FIG. 4 is a plan view showing an external electrode structure according to the first embodiment of the present invention;

FIG. 5 is a front view showing an external electrode structure according to the first embodiment of the present invention;

FIG. 6 is a plan view illustrating an external electrode structure according to a second embodiment of the present invention.

FIG. 7 is a front view showing an external electrode structure according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electronic component 2 Outer surface 3 External electrode 5 Folded electrode part 7 End surface electrode part 9 Conductive paste layer 13 Electroplating spreading part

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Seiji Watanabe 1-13-1 Nihonbashi, Chuo-ku, Tokyo TDK Corporation (58) Field surveyed (Int.Cl. ⁶ , DB name) H01G 4/252 H01F 27/29 H01G 4/228

Claims (2)

(57) [Scope of request for utility model registration] 1. A plurality of strip-shaped electrodes for external connection formed between an end face and at least one of upper and lower faces are arranged close to each other.
In column was surface mounting electronic components, said strip electrodes and more becomes conductive paste layer and the electroplating layer formed on the surface thereof, the conductive paste layer is Oite on each surface, the
An external electrode structure for an electronic component, wherein the width in the direction perpendicular to the arrangement direction is narrow at both ends and wide at an intermediate portion. 2. The external electrode structure of an electronic component according to claim 1, wherein the width of each portion of the conductive paste layer is formed so that the width of the electroplating layer is substantially constant.