JP2554693Y2 - 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 by incorporating it into 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. 6 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 drawing, on the printed circuit board 2, each lead terminal land 21 and heat radiation terminal land 22 correspond to the mounting position H of each lead terminal 11 and heat radiation terminal portion 12 of the electronic component 1.
Are provided respectively.

[0006] Each land 21 for a lead terminal is provided with an electronic component 1.
For soldering to the printed circuit board 2,
The resist is applied to portions other than the lands 21, that is, portions indicated by broken lines of the conductive pattern 20. 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 for improving 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. 6 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 large-area heat-radiating terminal portion 12 and the heat-radiating terminal portion land 22, and this is removed from the molten solder layer. When the printed circuit board 2 is separated, it flows backward with respect to the transport direction of the printed circuit board 2 and adheres to the lead terminals 11 behind, thereby often causing a solder bridge. When such a solder bridge occurs, the heat radiation terminal portion 12 and the lead terminal 11 are short-circuited, 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-mentioned problem, and in a printed circuit board on which an electronic component having a heat radiation terminal in the vicinity of a lead terminal is soldered by a dip method, And a printed circuit board capable of preventing a bridge generated between the lead terminal and the lead terminal.

[0010]

In order to solve the above-mentioned problems, the present invention provides a printed circuit board in which an electronic component having a heat radiating terminal near a lead terminal is soldered in a dip method. A plurality of notches are formed in the land for the heat radiation terminal, and when the electronic component is separated from the molten solder layer, the plurality of notches reduce the amount of molten solder attached to the heat radiation terminal and the land for the heat radiation terminal. In addition, the present invention is characterized in that a solder bridge generated between the heat radiation terminal portion and the lead terminal portion is prevented.

[0011]

In the printed circuit board 2 shown in FIGS. 1 to 4, a notch is provided in a part of the land 22 for the heat radiation terminal.
That is, when the printed circuit board 2 separates from the molten solder layer at the time of solder dipping of the printed circuit board, the notch is provided in the land 22 for the heat dissipation terminal. Is reduced by the presence of Therefore, by forming the land gap by the notch, the heat radiation terminal portion 12 and the heat radiation terminal portion land 22 are formed.
The solder adhering to the solder layer is easily separated from the molten solder layer, so that the amount of the solder flowing to the rear lead terminal 11 is reduced, and as a result, the solder between the heat radiation terminal portion 12 and the lead terminal 11 is maintained without impairing the heat radiation effect. Bridges can be prevented from occurring.

[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.
An example will be described. A large number of slits 23 extending in a direction substantially perpendicular to the mounting position H of the electronic component 1 are provided on the radiating terminal portion lands 22 of the printed circuit board 2.

In this printed circuit board, when the printed circuit board 2 is separated from the molten solder layer at the time of solder dipping, the slits 23 are provided in the radiating terminal portion lands 22. 23
Is reduced by the presence of Accordingly, the solder adhering to the heat radiating terminal portion 12 and the heat radiating terminal portion land 22 is easily separated from the molten solder layer, so that the amount of solder flowing to the rear lead terminal 11 is reduced, and the heat radiating terminal portion 12 and the lead terminal 11 It is possible to prevent the occurrence of a solder bridge between them. The provision of the slit 23 does not impair the heat radiation effect of the heat radiation terminal 12.

The slits 23 may be formed together when the conductive pattern 20 (FIG. 6) of the printed circuit board 2 is formed by a known etching method or the like, or a resist process after the formation of the conductive pattern 20 may be performed. Sometimes, they may be formed together with a resist. For convenience of explanation, the conductive pattern portion of the resist-coated portion is omitted in the drawings.

FIG. 2 shows a second embodiment. The land 22 for the heat radiation terminal of the printed circuit board 2 has a comb-shaped portion 24
Is provided. For convenience of explanation, the conductive pattern portion of the resist-coated portion is omitted in the drawing as in FIG.

FIG. 3 shows a third embodiment. In the land 22 for the heat radiation terminal of the printed circuit board 2, a slit 25 is provided at an appropriate angle (θ) with respect to the mounting position H of the electronic component 1 as in FIG. The conductive pattern 2
A resist is applied to a portion indicated by a broken line of 0.

FIG. 4 shows a fourth embodiment. A large number of holes 26 are formed in the radiating terminal portion lands 22 of the printed circuit board 2. For convenience of description, the conductive pattern portion of the resist-coated portion is omitted in the drawings.

In each of the embodiments shown in FIGS. 2 to 4, as in the first embodiment shown in FIG. 1, a slit 25, a comb-shaped portion 24, a hole 2
Since the printed circuit board 6 is provided, when the printed circuit board 2 separates from the molten solder layer at the time of solder dipping of the printed circuit board 2, the amount of solder attached to the heat radiation terminal portion 12 and the heat radiation terminal portion land 22 decreases due to the presence of the cutout portion. . Therefore,
Since the solder adhering to the heat radiation terminal portion 12 is easily separated from the molten solder layer, the amount of solder flowing to the rear lead terminal 11 is reduced, and the heat radiation terminal portion 12 and the lead terminal 11
It is possible to prevent the occurrence of a solder bridge between them.

It should be noted that the present invention is not limited to the above-described embodiment, but in essence, means for reducing the amount of molten solder adhering to the heat radiation terminal portion 12 and the heat radiation terminal portion land 22 is provided by means of the heat radiation terminal portion land 22. It should just be provided in.

The notches (slits) 23, 25
When the conductive pattern 20 of the printed circuit board 2 is formed by a known etching method or the like, it may be formed together,
Also, the resist may be formed together with the resist at the time of resist processing after the formation of the conductive pattern 20, and the method and shape are not limited at all.

[0022]

As described above, according to the present invention, a plurality of notches are provided in the land for the heat radiation terminal to reduce the amount of molten solder adhering to the heat radiation terminal and the land for the heat radiation terminal. Things.

Therefore, according to the present invention, it is possible to prevent a solder bridge generated between the heat radiation terminal portion and the lead terminal.

[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 view illustrating a third embodiment of the printed circuit board according to the present invention;

FIG. 4 is an explanatory view illustrating a fourth embodiment of the printed circuit board according to the present invention.

FIG. 5 is an explanatory diagram illustrating a conventional electronic component.

FIG. 6 is an explanatory diagram illustrating a state in which an electronic component is temporarily fixed to a printed circuit board in the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electronic component 2 Printed circuit board 11 Lead terminal 12 Heat dissipation terminal part 20 Conductive pattern 23, 25 Slit 24 Comb blade part 26 Hole

Claims (2)

(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 by a dip method, wherein a plurality of cutouts are formed in a land for the heat radiating terminal provided on the printed circuit board. When the electronic component separates from the molten solder layer, the plurality of cutouts reduces the amount of molten solder attached to the heat-radiating terminal portion and the land for the heat-radiating terminal portion, and the gap between the heat-radiating terminal portion and the lead terminal portion is reduced. A printed circuit board characterized by preventing a solder bridge generated on a printed circuit board. 2. The printed circuit board according to claim 1, wherein the notch formed in the land for the heat radiation terminal includes a plurality of slits and through holes.