JP2858252B2 - Electrode structure of electronic components for surface mounting - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement in an electrode structure of a surface mounting electronic component mounted on a printed circuit board by solder connection.

(Prior art) Electronic circuit units used in various communication devices, electronic devices, and the like require that surface mount electronic components such as piezoelectric devices, capacitors, and resistors be mounted on a wiring pattern on a printed circuit board by soldering or the like. In recent years, there has been an increasing demand for miniaturization of various communication devices, electronic devices, and the like.

3 (a) and 3 (b) are an explanatory view of the internal configuration and a bottom view of a piezoelectric device as an example of an electronic component for surface mounting. This piezoelectric device includes a base 1 having a conductor block subjected to a required molding process. A ceramic pedestal 2 integrated with the bottom surface of the base 1, a pair of leads 3 which hermetically penetrate the base 1 and the ceramic pedestal 2 and are electrically insulated from the base, and a crystal resonator supported on the leads 3 And the like, a cap 7 for hermetically sealing the upper space of the base including the piezoelectric element 5, and electrically connected to the leads 3 formed on the bottom surface of the ceramic pedestal 2 and exposed from the bottom surface. And a metallized area 8.
When the mounting electronic component having such a configuration is mounted on the printed circuit board P, the reflow is performed in a state where the metallized region 8 is placed on the connection conductor (land) 11 of the printed circuit board P via solder paste. This completes the electrical and mechanical connection.

FIGS. 4 (a) and 4 (b) show another conventional example, in which each lead 3 extending downward through a plastic pedestal 13 integrated with the bottom surface of the base 1 is extended outward. It has a configuration.

According to these electrode structures, mounting can be performed by reflow soldering without performing a complicated process such as inserting lead wires into through holes of a printed circuit board and soldering. Efficiency can be improved.

However, in the above-mentioned conventional electrode structure, since the thickness of the ceramic pedestal 2 and the thickness of the plastic pedestal 13 are each 0.5 mm or more, there is a limit in reducing the height of the entire component. There was a problem of going against it. Further, if these pedestals are forcibly guided, it becomes difficult to check the solder connection state after reflow, and there is a problem that a connection failure is easily overlooked.

(Object of the Invention) The present invention has been made in view of the above, and it is possible to easily and reliably confirm the connection state after solder connection, and reduce the mounting height while reducing the mounting height. The purpose of the present invention is to provide an electrode structure.

(Summary of the Invention) In a surface-mounting electronic component having a flat base and a lead penetrating the base, an attachment is locked from a bottom surface of the base to a peripheral protrusion, and an electrode pattern is formed from a bottom surface to a side surface of the attachment. The tip of the lead penetrating the attachment is electrically connected to an electrode pattern, and the attachment is formed by coating an insulating material over the entire outer peripheral surface of a thin plate-shaped metal core material, A lead insertion hole for preventing a short circuit between the core material and the tip of the lead penetrating the attachment is formed.

(Examples) Hereinafter, the present invention will be described in detail based on examples shown in the accompanying drawings.

FIGS. 1 (a), 1 (b) and 1 (c) are a front view, a bottom view and a side view, respectively, showing a partial cross section showing the structure of an embodiment of the present invention. Attachment 11 integrated on the bottom surface of base 10, a pair of leads 12 which hermetically penetrate base 10 and attachment 11 and are electrically insulated from the base, a crystal oscillator (not shown) supported on top of leads 12, etc. And a cap for hermetically sealing the upper space of the base including the piezoelectric element
14 and the attachment 11 while being integrated with the bottom portion of the insulating material covering the entire outer peripheral surface of the attachment 11.
It has an electrode pattern 15 that penetrates through the electrode 11 and is electrically connected to the tip end surface (lower end surface) of the lead 12 exposed from the bottom surface.

The attachment 11 is a plate-like body having a thickness of 0.3 mm or less in which a heat-resistant plastic resin 31 such as polyimide is coated and integrated on the entire outer peripheral surface of a thin conductive plate 30 as a core material. Is increasing. After bending both ends of the core material upward at right angles as shown in the figure, the tip portion is further bent toward the cap 14 so that the attachment 11 can be fixedly locked to the overhang portion of the base peripheral edge. As described above, besides bending both ends of the plate-shaped attachment 11 itself and locking the periphery of the base, a claw or the like is extended from both ends of the attachment 11 and configured to be locked by the claw. You may.

When the lead 12 and the copper plate in the attachment 11 come into contact with each other, a short circuit occurs. Therefore, an opening (lead insertion hole) 30A for preventing short circuit is formed in the copper plate portion through which the lead penetrates.

Electrical and mechanical connection between the electrode pattern 15 and the tip of the lead 12 is made by solder connection or a conductive adhesive. The electrode pattern 15 extends from the position where the tip of the lead 12 on the bottom surface of the attachment is exposed to the side surface of the first bent portion 11a. By extending the electrode pattern portion 15a on the side surface of the bent portion 11a, it is easy to confirm the spread state of the solder when this mounted component is connected to a printed circuit board (not shown) by soldering.

FIG. 2 shows an example of an attachment used in the present invention. A non-copper plate region 21 is formed in a central portion of a copper plate 20, and a pair of lead insertion holes 22 are formed in the non-copper plate region 21.
A coil 23 having a pattern formed is provided between 22 and an outer peripheral surface thereof is covered with an insulating resin film 24.

The coil 23 has a configuration in which a U-shaped bend is formed continuously,
By forming the coil in this manner, the parallel capacitance can be canceled and the capacitance ratio can be reduced. Also,
The upper and lower surfaces of the coil pattern 23 can be integrated with the copper plate 20 by coating with an insulating film 24.

As in the above embodiment, the attachment 11 may be bent to obtain a mechanical connection with the base, and at the same time, the base may be fixed to the attachment with an adhesive to reinforce the attachment. By reinforcing with an adhesive in this way, the thickness of the attachment itself can be further reduced.

As described above, according to the present invention, by using the thin-walled attachment, an electrode structure suitable for solder connection by reflow can be obtained without increasing the mounting height.

(Effect of the Invention) As described above, according to the present invention, it is possible to reduce the mounting height while easily and reliably confirming the connection state after solder connection.

[Brief description of the drawings]

1 (a), 1 (b) and 1 (c) are a front view, a bottom view, and a side view showing a configuration of an embodiment of the present invention. FIG. 2 is an explanatory view of an example of an attachment used in the present invention. 3 (a) and 3 (b) and FIGS. 4 (a) and 4 (b) are explanatory views of a conventional example. 10 ... Base, 11 ... Attachment 12 ... Lead, 14 ... Cap 15 ... Electrode pattern

Claims (1)

(57) [Claims] 1. A surface-mounting electronic component having a flat base and a lead penetrating the base, wherein an attachment is locked from a bottom surface of the base to a peripheral projection, and an electrode pattern is formed from a bottom surface to a side surface of the attachment. And electrically connecting a tip end of the lead penetrating the attachment and an electrode pattern, wherein the attachment is formed by coating an insulating material over the entire outer peripheral surface of a thin plate-shaped metal core material, An electrode structure for a surface mount electronic component, wherein a lead insertion hole for preventing a short circuit between the core material and a tip portion of the lead penetrating the attachment is formed.