JPH0521944A - Printed-wiring board - Google Patents

Abstract

PURPOSE:To enable reliability and mechanical strength of a needed electrical connection to be secured without increasing the surface area of a land. CONSTITUTION:Lands 3a and 3b which are regular octagons whose interior angles are not acite angles are provided at both edge periphery portions of a through-hole 2 which is made in a double-sided printed-wiring board 1 and specified wiring pattern 4a and 4b are connected to one of 8 vertices of each land. No tear-drop treatment needs to be performed at a connection portion between the lands 3a and 3b and the wiring patterns 4a and 4b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed wiring board having a conductor on one side or both sides and a multilayer printed wiring board, and more particularly to a printed wiring board having an improved shape of a land provided around a through hole.

[0002]

2. Description of the Related Art In a printed wiring board having a conductor layer on one side or both sides and a multilayer printed wiring board having a structure in which one side or double-sided printed wiring boards are laminated, component terminals are connected to conductor layers or between conductor layers. A through hole is provided for
A land for connecting a predetermined conductor pattern is formed around the through hole. The size and shape of the land have a sufficient area for ensuring the reliability of electrical connection between the mounting parts to be connected or the conductor layers and the mechanical strength of the land itself, and the size of the land and that of the adjacent land. It is necessary to design so that a sufficient distance is maintained so that a short circuit does not occur between them.

Conventionally, circular, elliptical or square lands have been used. However, due to design restrictions due to the density of wiring patterns, it is necessary to make the size of the land sufficiently larger than the diameter of the through hole. If it is impossible, it is necessary to provide the tear drop 33a as shown in FIG. 3 to secure the reliability and mechanical strength of the above-mentioned electrical connection.

[0004]

According to the above-mentioned conventional technique, as described above, when the land of a sufficient size cannot be provided around the through hole due to the design restrictions of the wiring pattern, the land It is necessary to perform tear drop processing at a predetermined position, which has a drawback that the design becomes complicated.

The present invention has been made in view of the above-mentioned problems of the prior art. Even when the size of the land is limited due to design restrictions of the printed wiring board and the like, the present invention does not interfere with the wiring pattern. It is an object of the present invention to provide a printed wiring board having lands capable of ensuring sufficient reliability of electrical connection and mechanical strength and capable of smoothly connecting to the wiring pattern. To do.

[0006]

In order to achieve the above-mentioned object, the printed wiring board of the present invention is characterized in that a polygonal land having no internal acute angle is connected to the wiring pattern.

The wiring pattern can be connected to one of a plurality of vertices of a polygonal land. The polygonal land may be a land provided with a through hole or a land having no through hole such as an inspection land.

[0008]

By using polygonal lands, the printed wiring board of the present invention has electrical connection reliability and mechanical strength comparable to those of lands whose outer shape is the circumscribing circle of the polygon. Further, by connecting the wiring pattern to one of the plurality of vertices of the polygonal land, the outer shape of the connection portion between the wiring pattern and the land can be made into a smooth curved shape.

[0009]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic partial bottom view showing a part of an embodiment of the present invention. The double-sided printing plate 1 is a resist coat 1a.
And a through hole 2, and the through hole 2
Lands 3a and 3b are respectively provided at both ends of each of the lands, and each of the lands 3a and 3b is formed by a conductor having a regular octagonal outer shape as a polygonal land having no acute angle at the inner angle. The wiring pattern 4b arranged on the lower surface of the double-sided printed wiring board 1 is connected to one of the eight apexes of the regular octagonal land 3b, and the wiring pattern 4a arranged on the upper surface of the printed wiring board 1 in the same manner. Is connected to one of the eight vertices of the regular octagonal land 3b.

As described above, since each land 3a, 3b has a regular octagonal outer shape, mechanical strength and electrical connection comparable to the circular land 5 (shown by a broken line) having a circle circumscribing the regular octagon as an outer shape. It is possible to ensure the reliability of the above, and there is less risk of causing a short circuit due to a solder bridge or the like between adjacent lands, as compared with the above-mentioned circular land.

Further, since each wiring pattern 4a, 4b is connected to one of the eight vertices of the regular octagonal lands 3a, 3b, respectively, the lands 3a, 3b and the wiring patterns 4a, 4b are connected to each other. The connection between them has a gentle curved shape similar to the case where the tear drop process is applied. In addition, although the lands 3a and 3b having the regular octagonal outer shape are used in the above-described embodiment, the lands 3a and 3b are not limited to the regular octagon.
Any shape of land may be used as long as it has a polygonal shape with no acute inner angle.

Further, although the above-mentioned lands 3a and 3b are for connecting the conductors provided on both surfaces of the printed wiring board 1, through holes for mounting parts of regular octagonal lands are similarly formed. In this case, the consumption of solder for connecting the leads or terminals of the component can be reduced as compared with the circular land.

In the above embodiment, only the lands 3a and 3b provided around the through hole 2 are shown, but a land having no through hole, for example, an inspection for contacting a contact probe in an inspection step after mounting. It goes without saying that the land for use can also be polygonal as described above.

[0015]

Since the present invention is configured as described above, it has the following effects.

Since it is possible to secure the required reliability and mechanical strength of the electrical connection without increasing the surface area of the land of the printed wiring board, it is possible to reduce restrictions on the design of the wiring pattern of the printed wiring board. You can Further, since the outer shape of the connecting portion between the predetermined wiring pattern and the land can be made into a smooth curved shape without performing the tear drop processing, the design of the wiring pattern can be simplified.

[Brief description of drawings]

FIG. 1 is a partial schematic bottom view showing a part of an embodiment of the present invention.

FIG. 2 is a partial schematic cross-sectional view taken along the line AA ′ in FIG.

FIG. 3 is a partial schematic plan view showing the shape of a land used in a conventional example. 1 Printed Wiring Board 1a Resist Coat 2 Through Holes 3a, 3b Lands 4a, 4b Wiring Pattern 5 Circular Land 33 Land 33a of Conventional Example Tear Drop

Claims (4)

[Claims] 1. A printed wiring board comprising a wiring pattern and polygonal lands having no inner corners connected to the wiring pattern. 2. The printed wiring board according to claim 1, wherein the wiring pattern is connected to one of a plurality of vertices of a polygonal land. 3. The printed wiring board according to claim 1, wherein the polygonal land is provided with a through hole. 4. The printed wiring board according to claim 1, wherein the polygonal land is an inspection land for contacting a contact probe of an inspection machine.