JP2554694Y2 - Printed board - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed circuit board on which electronic components such as an IC having a heat radiation terminal portion near a lead terminal are soldered by a dip method.

[0002]

2. Description of the Related Art There is a dip method as a method of soldering an electronic component to a printed circuit board. As is well known, the dip method mounts a plurality of electronic components on one or both sides of a printed circuit board, transports the printed circuit board substantially horizontally in this state, and immerses one side of the printed circuit board in the surface of the molten solder. Are soldered to the conductive patterns of the printed circuit board. According to this method, a large number of electronic components mounted on the printed circuit board can be soldered at a time, so that it is possible to reduce the cost without labor.

[0003]

In the dip method described above, the printed circuit board is transported substantially horizontally and one side thereof is immersed in the surface of the molten solder layer. Therefore, when the printed circuit board separates from the solder layer, it is placed on the printed circuit board. Solder attached to a lead terminal of an electronic component is separated from the molten solder layer. At this time, in some cases, the rear end of the adhered solder flows and adheres to the lead terminal behind,
So-called solder bridges may occur. This solder bridge is more likely to occur as the interval (pitch) between the lead terminals is smaller.

By the way, when a completed printed circuit board is used in an apparatus, a heat radiation terminal portion 12 is provided on an electronic component which generates a large amount of heat as shown in FIG. Since the heat radiation terminal portion 12 is generally provided at the center of the electronic component 1 main body, it is arranged between the lead terminals 11.

FIG. 4 shows a state in which such an electronic component 1 is mounted on a printed circuit board 2 and shows a state before a soldering process is performed. In this figure, on the printed circuit board 2, lands 21 for the lead terminals and lands 22 for the radiating terminal are provided corresponding to the mounting positions H of the lead terminals 11 and the radiating terminal 12 of the electronic component 1, respectively. I have.

[0006] Each land 21 for a lead terminal is provided with an electronic component 1.
For soldering to the printed circuit board 2,
A portion other than the land 21, that is, the conductive pattern 20
A portion indicated by a broken line is provided with a resist. The electronic component 1 is electrically connected to the printed board 2 via the land 21.

The radiating terminal portion lands 22 are for soldering the radiating terminal portions 12 of the electronic component 1 onto the printed circuit board 2 and have an appropriate land area in order to enhance the heat radiation effect. A resist is applied to other portions indicated by broken lines, and is connected to, for example, an earth pattern. Before the soldering process shown in FIG. 4 is performed, the electronic component 1 is temporarily fixed to the printed board 2 with an adhesive or the like.

In this state, when the electronic component 1 is soldered to the printed circuit board 2 by a dip method, a large amount of solder adheres to the heat radiation terminal portion 12 having a larger area than the lead terminal 11, and this is removed from the molten solder layer. At the time of separation, it flows backward with respect to the transport direction of the printed circuit board 2. This solder adheres to the rear lead terminal 11, which often causes a solder bridge. When such a solder bridge occurs, the heat radiation terminal portion 12 and the lead terminal 11
A short circuit may occur, and in some cases, the electronic component 1 may be damaged.

In view of the above, the present invention has been made to solve the above-described problem. In a printed circuit board on which an electronic component having a heat radiating terminal in the vicinity of a lead terminal is soldered by a dip method, a heat radiating terminal and a lead are provided. A printed circuit board capable of preventing a solder bridge generated between terminals is proposed.

[0010]

According to the present invention, in order to solve the above-mentioned problems, in a printed circuit board to which an electronic component having a heat radiation terminal portion near a lead terminal is soldered by a dip method, The solder attachment portion having a height in the thickness direction of the board is formed in connection with the rear of the land for the heat dissipation terminal with respect to the direction, and when the electronic component separates from the molten solder layer, the heat attachment terminal portion and the solder attachment portion are formed by the solder attachment portion. The present invention is characterized in that the amount of molten solder adhering to the radiating terminal portion land is reduced to prevent a solder bridge generated between the radiating terminal portion and the lead terminal portion.

[0011]

1 and 2, the solder attaching means 3
Both 0 and 50 also have a predetermined height in the thickness direction of the printed circuit board 2. This thickness direction is a direction in which the electronic component separates from the molten solder layer at the time of solder dipping. Therefore, when the electronic component 1 separates from the molten solder layer, the molten solder attached to the heat radiation terminal portion 12 It is also guided and moved in the height direction of the soldering means 30 and 50 provided in series. As a result, the solder adheres not only to the plane of the land 22 but also to the height direction of the solder attaching means 30, 50. As a result, the amount of molten solder adhering to the heat radiating terminal portion 12 decreases. As a result, the heat radiation terminal 1
It is possible to prevent a solder bridge generated between the lead terminal 2 and the lead terminal 11.

[0012]

Next, an embodiment of a printed circuit board according to the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a first embodiment of a printed circuit board according to the present invention. The land 22 for the heat radiation terminal of the printed circuit board 2 is separated from the lead terminal 11 and the heat radiation terminal 12 of the electronic component 1 behind the land 22 for the heat radiation terminal in the dip direction of the printed circuit board 2 indicated by the arrow. And a chip-shaped surface-mounted electronic component 30 having a predetermined height also in the thickness direction of the printed circuit board 2 is arranged so as to be connected to the land 22 for the heat radiation terminal portion.
This thickness direction is a direction in which the electronic component separates from the molten solder layer during solder dipping. It should be noted that the conductive pattern portion where the resist is applied is omitted in the drawing.

In the printed circuit board 2, since the surface-mounted electronic components 30 are provided so as to be connected to the radiating terminal portion lands 22, when the printed circuit board 1 separates from the molten solder layer at the time of solder dip, the radiating terminal portion 12 is formed. The attached solder travels along the plane of the heat-dissipating terminal portion land 22 and moves to the surface-mounted electronic component 30 having a predetermined height.
As a result, the solder is dispersed not only in the plane of the land 22 but also in the height direction of the surface-mounted electronic component 30, so that the amount of solder attached to the heat radiation terminal portion 12 is reduced.

Accordingly, the amount of solder flowing from the heat radiation terminal portion 12 to the rear lead terminal 11 is reduced, and it is possible to prevent the occurrence of a solder bridge between the heat radiation terminal portion 12 and the lead terminal 11.

Reference numeral 31 denotes a land for soldering the surface-mounted electronic component 30 to a printed circuit board. The surface-mounted electronic component 30 is electrically connected to the printed circuit board by the land 31 and the land 22 for the heat radiation terminal. However, in the case of the present invention, since the surface-mounted electronic component 30 is used as a solder attaching means, the surface-mounted electronic component 30 and the land 31 may be dummy components and lands that do not constitute an electric circuit.

FIG. 2 shows a second embodiment. The land 22 for the heat radiation terminal portion of the printed circuit board 2 has a height direction (thickness direction) behind the land 22 for the heat radiation terminal portion with respect to the dip direction of the printed circuit board 2 indicated by an arrow.
And a lead-like projection 50 extending in the direction shown in FIG.

In the printed circuit board 2 shown in FIG. 2, since the lead-like projections 50 for solder attachment are provided in connection with the lands 22 for the heat dissipation terminal, the printed circuit board 2 is separated from the molten solder layer at the time of solder dipping. At this time, the solder adhering to the heat radiating terminal portion 12 is guided from the heat radiating terminal portion land 22 to the lead-like protrusion 50 for solder adhesion and moves. As a result, the amount of solder adhered to the heat radiation terminal portion 12 is reduced.

Accordingly, the amount of solder flowing from the heat radiation terminal portion 12 to the rear lead terminal 11 is reduced, and it is possible to prevent the occurrence of a solder bridge between the heat radiation terminal portion 12 and the lead terminal 11.

If the above-mentioned solder attaching means 30 and 50 preferably have a thickness or height greater than the thickness of the heat radiation terminal portion 12 or the lead terminal 11, the effect is further enhanced.

[0021]

As described above, according to the present invention, the solder attaching means having a height in the thickness direction of the printed circuit board is provided so as to be connected to the back of the land for the heat radiation terminal.

Therefore, according to the present invention, since the solder adhering to the heat radiating terminal is guided to the solder adhering means and flows, the amount of solder adhering to the heat radiating terminal is reduced. There is an effect that it is possible to prevent a solder bridge generated between them.

[Brief description of the drawings]

FIG. 1 is an explanatory view illustrating a first embodiment of a printed circuit board according to the present invention.

FIG. 2 is an explanatory view illustrating a second embodiment of the printed circuit board according to the present invention.

FIG. 3 is an explanatory diagram illustrating an electronic component in a conventional example.

FIG. 4 is an explanatory view illustrating a state in which an electronic component is temporarily fixed to a printed circuit board in a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electronic component 2 Printed circuit board 11 Lead terminal 12 Heat dissipation terminal part 20 Conductive pattern 21 Land for lead terminal 22 Land for heat dissipation terminal part 30 Surface mount electronic component 31 Land of surface mount electronic component 50 Lead-shaped protrusion

Claims (3)

(57) [Scope of request for utility model registration] 1. A printed circuit board to which an electronic component having a heat radiating terminal in the vicinity of a lead terminal is soldered in a dip method, wherein the electronic component is connected rearward of a land for a heat radiating terminal to a dip direction of the printed circuit board. A solder-attached portion having a height in the thickness direction of the substrate is formed, and when the electronic component separates from the molten solder layer, the solder-attached portion reduces the amount of molten solder attached to the heat-radiating terminal portion and the land for the heat-radiating terminal portion. A printed circuit board, wherein a solder bridge generated between the heat radiation terminal portion and the lead terminal portion is prevented. 2. The printed circuit board according to claim 1, wherein said solder attaching means is a surface mount component. 3. The printed circuit board according to claim 1, wherein said solder attaching means is a lead-like projection.