JP2006156682A - Module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a module having a structure hardly generating short-circuit due to solder between the terminals of a flexible printed circuit board. <P>SOLUTION: The module 10 is equipped with a base 12, a lead pin 14, a sealing member 16, and a flexible printed circuit board 18. The sealing member 16 fills a gap between the lead pin 14 penetrated through the hole of the base 12 and the lead pin 14. The lead pin 14 is penetrated through the through-hole of the flexible printed circuit board 18. In the flexible printed circuit board 18, a second surface 20b facing the base 12, and a terminal pad 24 are covered by a coverlay 26. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a module having a suitable mounting structure of a flexible printed circuit board to lead pins.

  Patent Documents 1 and 2 below disclose a solder joint technique between a lead pin supported by a base and a terminal such as a flexible printed circuit board. Generally, a flexible printed circuit board has a base body provided with a through hole. The base has a first surface and a second surface opposite to the first surface, and terminals are provided along the edge of the through hole on the first surface and the second surface. ing. These terminals are electrically connected through through-hole plating. The flexible printed circuit board is mounted with the second surface facing the base, and the lead pins are inserted into the through holes. The lead pin is soldered to the terminal on the first surface.

Patent Document 3 below discloses a solder joint technique between a wiring pattern provided on a circuit board as a base and a terminal provided on a flexible printed board. Also in this flexible printed circuit board, the terminals are provided along the edges of the through holes, and the terminals and the flexible printed circuit board are electrically joined by solder supplied to the through holes.
JP 2003-173832 A US Pat. No. 5,802,711 Japanese Utility Model Publication No. 05-029178

  However, if the supplied solder becomes excessive, the solder may be transmitted between the base and the second surface of the flexible printed circuit board, and the adjacent terminals may be short-circuited.

  Therefore, an object of the present invention is to provide a module having a structure in which a short circuit due to solder is unlikely to occur between terminals of a flexible printed circuit board.

  The module of the present invention includes a metal base, a lead pin, a sealing member, and a flexible printed board. The base has a mounting surface and a hole extending from the mounting surface. The lead pin is provided in the hole of the base and protrudes from the mounting surface. The sealing member seals between the inner surface of the hole and the lead pin. The flexible printed circuit board has a through hole into which a lead pin is inserted, and is mounted on a mounting surface. The flexible printed circuit board has a base body, and the base body has a first surface and a second surface that is opposite to the first surface and faces the mounting surface. A first terminal pad is provided along the edge of the through hole on the first surface, and the first terminal pad is soldered to the lead pin. A second terminal pad is provided along the edge of the through hole on the second surface. A plated film is provided on the inner surface of the through hole, and the plated film electrically connects the first terminal pad and the second terminal pad. An insulating cover lay is provided on the second surface and the second terminal pad. The diameter of the through hole of the flexible printed board is smaller than the outer diameter of the sealing member.

  According to this configuration, since the second terminal pads are covered by the coverlay, a short circuit due to solder between adjacent second terminal pads does not occur. Moreover, since the diameter of the through hole is smaller than the outer diameter of the sealing member, the solder supplied to the through hole is retained in the through hole by the cooperation of the sealing member and the coverlay.

  In the module of the present invention, it is preferable that the surface of the sealing member on the side of the flexible printed board has a countersink surface around the lead pin, and the diameter of the through hole is smaller than the diameter of the countersink surface. . According to this configuration, a larger gap for fastening solder is provided between the coverlay and the sealing member.

  As described above, according to the present invention, a module having a structure in which a short circuit due to solder hardly occurs between terminals of a flexible printed board is provided.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals.

  FIG. 1 is a perspective view of a module according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the module according to the embodiment of the present invention. The module 10 shown in FIGS. 1 and 2 is used as a so-called coaxial optical transmission subassembly or optical reception subassembly. The module 10 includes a base 12, lead pins 14, a sealing member 16, and a flexible printed board 18.

  The base 12 is made of metal and has a mounting surface 12a for mounting the flexible printed circuit board 18 and an inner surface 12b that defines a hole extending from the mounting surface 12a. The base 12 can mount a semiconductor device such as a semiconductor light emitting element or a semiconductor light receiving element on the surface opposite to the mounting surface 12a.

  A lead pin 14 is passed through the hole of the base 12, and the lead pin 14 protrudes from the mounting surface 12a. The lead pin 14 is electrically connected to a semiconductor device mounted on the base 12, for example.

  A sealing member 16 is provided between the inner surface 12 b of the hole and the lead pin 14. The sealing member 16 is an insulating member such as low melting point glass. The surface of the sealing member 16 facing the flexible printed circuit board 18 has a countersink surface 16a.

  The flexible printed circuit board 18 includes a base body 20, first terminal pads 22, second terminal pads 24, and a coverlay 26.

  The base 20 has a first surface 20a and a second surface 20b. The second surface 20b is on the side opposite to the first surface 20a, and the flexible printed circuit board 18 is mounted on the base 12 so that the second surface 20b faces the mounting surface 12a. The base body 20 is provided with a through hole extending from the first surface 20a to the second surface 20b.

  A first terminal pad 22 is provided on the first surface 20a along the edge of the through hole. A second terminal pad 24 is provided on the second surface 20b along the edge of the through hole. On the inner surface 20c of the through hole and the first terminal pad 22, a plating film 20d is provided. The first terminal pad 22 and the second terminal pad 24 are electrically connected by the plating film 20d. The first terminal pad 22 and the second terminal pad 24 are preferably made of a material having good thermal conductivity such as copper foil. Note that a wiring pattern electrically connected to the first terminal pad 22 is provided on the first surface 20a (see FIG. 1).

  A coverlay 26 is provided on the second surface 20 b and the second terminal pad 24. The coverlay 26 is an insulating member and is made of, for example, an insulating plastic film. The cover lay 26 also has a diameter that matches the diameter of the through hole provided in the base body 20, and the through hole is formed so as to be continuous with the through hole.

  The through hole of the flexible printed circuit board 18 is smaller than the outer diameter of the sealing member 16, and in this embodiment, is smaller than the diameter of the countersink surface 16a. Lead pins 14 from the base 12 are inserted into the through holes of the flexible printed circuit board 18, and the lead pins 14 and the first terminal pads 22 are electrically connected by solder 28. In the embodiment shown in FIG. 2, the lead pin 14 and the first terminal pad 22 are electrically connected via the solder 28 and the plating film 20d.

  Hereinafter, the operation of the module 10 of the present embodiment will be described. At the time of solder bonding, solder and flux are supplied in a state where the first terminal pads 22 and the lead pins 14 are heated by a soldering iron. The melted solder spreads over the first terminal pads 22 and the lead pins 14. The solder is transmitted through the plating film 20d and fills the through hole, whereby the connection by the solder 28 as shown in FIG. 2 is achieved.

  The molten solder not only spreads on the metal surface and the metal plating surface, but also spreads on the insulator due to surface tension when the gap between the members is narrow even on the insulator. However, since the cover lay 26 is provided, the solder is retained in the through hole by the cooperation of the cover lay 26 and the sealing member 16 even when the amount of supplied solder is excessive. Thereby, a short circuit between the second terminal pads 24 is prevented.

  In addition, the space and the gap for fastening the solder are further increased by the above-described countersink surface 16a. Therefore, the allowable range of the solder supply amount is larger.

FIG. 1 is a perspective view of a module according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the module according to the embodiment of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Module, 12 ... Base, 14 ... Lead pin, 16 ... Sealing member, 18 ... Flexible printed circuit board, 20 ... Base | substrate, 20a ... 1st surface, 20b ... 2nd surface, 20d ... Plating film, 22 ... 1st 1 terminal pad, 24 ... second terminal pad, 26 ... coverlay, 28 ... solder.

Claims (2)

A metal base having a mounting surface and a hole;
A lead pin provided in the hole and protruding from the mounting surface;
A sealing member that seals between the inner surface of the hole and the lead pin;
A flexible printed circuit board having a through hole into which the lead pin is inserted and mounted on the mounting surface;
With
The flexible printed circuit board is
A base body having a first surface and a second surface opposite to the first surface and facing the mounting surface;
A first terminal pad provided along an edge of the through hole in the first surface, and solder-bonded to the lead pin;
A second terminal pad provided along an edge of the through hole in the second surface;
A plating film provided on the inner surface of the through hole and electrically connecting the first terminal pad and the second terminal pad;
An insulating coverlay provided on the second surface and the second terminal pad;
Have
The diameter of the through hole is smaller than the outer diameter of the sealing member,
module. The surface on the flexible printed circuit board side of the sealing member has a countersink surface around the lead pin,
The diameter of the through hole is smaller than the diameter of the countersunk surface,
The module according to claim 1.

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