JPH11145598A - Printed board and electronic device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate solder slumps in a printed board in which chip parts are subjected to reflow soldering. SOLUTION: Chip parts are attached to a printed board 11, and their electrodes are formed on lands 12 on the printed board 11 through reflow soldering. The lands 12 are formed on the bottom of a recessed part 16, surrounded by resists 14 and 15. Thus solders slumps can be eliminated on the printed board during reflow soldering.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a printed circuit board on which a surface mount component is reflow-soldered, and an electronic apparatus using the printed circuit board.

[0002]

2. Description of the Related Art A conventional printed circuit board to which a surface mount component is reflow-soldered will be described. As shown in FIG. 5, in a conventional printed circuit board, a chip component 3 which is a surface mount component is mounted on a printed circuit board 2 on which a copper foil land 1 is formed, and reflow soldered with cream solder 4. That is, the cream solder 4 is applied to the land 1 as shown in FIG. 6, and the chip component 3 is placed on the land 1 to which the cream solder 4 is applied as shown in FIG. 7 and soldered by reflow heat. Was. Here, reference numeral 5 denotes resist printing provided on the printed circuit board 2.

[0003]

However, in such a conventional configuration, the cream solder 4 may sag and short-circuit with the pattern 6 provided close to the land 1. In addition, since the cream solder 4 was dripped, the amount of solder between the land 1 and the electrode 7 formed on the chip component 3 was small, so that strong soldering could not be performed.

An object of the present invention is to solve such a problem, and an object of the present invention is to provide a printed circuit board free of solder dripping.

[0005]

In order to achieve this object, the land of the printed circuit board according to the present invention is configured such that its periphery is provided on the bottom surface of a concave portion formed of an insulating material.

[0006] Thereby, when reflow soldering is performed, it is possible to eliminate the solder dripping of the printed circuit board.

[0007]

According to a first aspect of the present invention, there is provided a printed circuit board on which a surface mount component is mounted, and an electrode of the surface mount component provided on the printed circuit board and reflow soldered. The land is a printed circuit board provided on the bottom surface of a concave portion formed of an insulator, and the periphery of the land is surrounded by the concave portion formed of an insulator. It does not accumulate on the surface and flow out. Therefore, even if a pattern is provided near this land, there is no short circuit. Further, since the solder is accumulated in the concave portion, the contact area with the electrode of the surface mount component is increased, the soldering strength is increased, and reliable soldering can be performed.

According to a second aspect of the present invention, there is provided the printed circuit board according to the first aspect, wherein a copper foil pattern is provided around the land and a resist print is provided so as to cover the copper foil pattern. Since the resist printing is provided so as to cover the copper foil pattern, the upper surface of the copper foil pattern and the upper surface of the land have the same height. Therefore,
Since the resist printing is provided only on the copper foil pattern, the land becomes the bottom of the concave portion as a result. As described above, if the copper foil pattern is provided around the land, the concave portion can be formed only by one-time resist printing using the copper foil pattern.

According to a third aspect of the present invention, there is provided the printed circuit board according to the first aspect, wherein a resist print is provided around the land, and a second resist print is further provided on the resist print. When there is no copper foil pattern near the land, the concave portion can be formed by two times of resist printing.

According to a fourth aspect of the present invention, there is provided the printed circuit board according to the third aspect, wherein the second resist printing is black, and since the second resist printing is black, forgetting to apply cream solder, etc. Can be easily visually inspected.

According to a fifth aspect of the present invention, there is provided the printed circuit board according to the fourth aspect, wherein the second resist printing is slightly larger than the outer shape of the surface mount component. Since it is slightly larger than the outer shape of the surface-mounted component, it is possible to easily visually inspect whether the surface-mounted component is left unattached or the like.

According to a sixth aspect of the present invention, there is provided an electronic apparatus using the printed circuit board, wherein the surface-mounted component is mounted on any one of the printed circuit boards according to the first to fifth aspects. Because the periphery of the land of the printed circuit board that constitutes is surrounded by a recess formed of an insulator,
Solder does not accumulate in this concave portion and flow out. Therefore, even if a pattern is provided near this land, there is no short circuit. Further, since the solder is accumulated in the concave portion, the contact area with the electrode of the surface mount component is increased, the soldering strength is increased, and reliable soldering can be performed.

According to a seventh aspect of the present invention, there is provided a printed circuit board on which a surface mount component is mounted, and a land provided on the print board and to which electrodes of the surface mount component are reflow soldered. The space between the electrodes of the mounted component is a printed circuit board having a more convex shape than the land, and a gap is formed between the electrode of the surface mounted component and the land by this convex shape, and the gap is filled with solder. And the bonding area becomes large and the bonding becomes strong.

According to an eighth aspect of the present invention, the copper foil pattern is provided between both lands of the surface mount component separately from these lands, and a resist print is provided so as to cover the copper foil pattern. Since the printed circuit board is described, and the copper foil pattern is provided between the lands, the upper surface of the copper foil pattern and the upper surface of the land have the same height. Therefore,
Since the resist printing is provided only on the copper foil pattern, the land becomes a convex shape from the upper surface of the land as a result. In this way, if a copper foil pattern is provided between the lands, a gap can be formed between the electrode of the surface mount component and the land only by one-time resist printing using the copper foil pattern. Since the solder is filled, the bonding area between the electrode and the land becomes large, and the bonding becomes strong.

According to a ninth aspect of the present invention, there is provided the printed circuit board according to the eighth aspect, wherein the periphery of the land is provided on a bottom surface of a concave portion formed by resist printing, and the periphery of the land is formed by resist printing. Since the solder is surrounded by the recess, the solder does not accumulate in the recess and flow out. Therefore,
Even if a pattern is provided near this land, no short circuit occurs. Further, since the solder is accumulated in the concave portion, the contact area with the electrode of the surface mount component is increased, the soldering strength is increased, and reliable soldering can be performed.

Further, since the copper foil pattern is provided between the lands, the upper surface of the copper foil pattern and the upper surface of the land have the same height. Therefore, since the resist printing is provided only on the copper foil pattern, the land has a convex shape from the upper surface of the land as a result. In this way, if a copper foil pattern is provided between lands, this copper foil pattern is utilized,
A gap is created between the electrode of the surface mount component and the land only by one-time resist printing, and this gap is filled with solder,
The bonding area between the electrode and the land is further increased, and the bonding is strengthened.

According to a tenth aspect of the present invention, there is provided an electronic device using the printed circuit board, wherein the surface-mounted component is mounted on any one of the printed circuit boards according to the seventh to ninth aspects. Is surrounded by a concave portion formed of an insulator, so that the solder does not collect in the concave portion and flow out. Therefore, even if a pattern is provided near this land, there is no short circuit. Further, since the solder is accumulated in the concave portion, the contact area with the electrode of the surface mount component is increased, the soldering strength is increased, and reliable soldering can be performed.

Further, since the copper foil pattern is provided between the lands of the printed circuit board constituting the electronic device, the land has a convex shape from the upper surface of the land. Accordingly, a gap is formed between the electrode and the land, and the gap is filled with the solder, so that the bonding area between the electrode and the land is increased, so that an electronic device formed of a printed board with strong bonding can be obtained.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a main part of a printed circuit board according to the present embodiment. In FIG. 1, reference numeral 11 denotes a printed circuit board. On the upper surface of the printed circuit board 11, a land 12 formed of a copper foil to which an electrode (not shown) 7 of a chip component (not shown) 3 is connected by soldering. Is provided. Reference numeral 13 denotes a copper foil pattern provided between the lands 12. Reference numeral 14 denotes green resist printing, which is provided so as to cover the periphery of the land 12 and the copper foil pattern 13. Reference numeral 15 denotes a black resist print, which is provided so as to cover the green resist print 14 from above. The thickness of each of these resist prints 14 and 15 is approximately 20 microns. Also, the thickness of the copper foil pattern is about 2
0 μm, and the concave portion 16 is formed with the land 12 as the bottom surface. The outside of the recess 16 is the land 1
20 microns around the top, 40 between lands
This means that the projection is a micron. Land 1
Since the concave portion 16 having the bottom surface 2 is formed, the solder accumulates in the concave portion 16 and does not sag. In addition, the space between the lands 12 has a shape corresponding to the resists 14 and 15, that is, a convex shape of approximately 40 microns. Therefore, land 1
A gap of about 40 μm is formed between the electrode 7 and the land of the chip component 3.
2 is firmly fixed.

FIG. 2 is a plan view of FIG. As shown in FIG. 2, when the printed circuit board 11 is viewed from above, the black resist print 15 is shaped like glasses. 12 is a land. The area around the land 12 is shaped like glasses, and the width 17 is 0.2 mm. Since the black resist 15 is used as described above, if the user forgets to apply the cream solder to the land 12 or forgets to attach the chip component 3, it can be found immediately.

In this embodiment, the double resist printing is used. However, the copper resist pattern is used, and the concave portion 16 is formed by forming the copper foil pattern around the land 12 even in the single resist printing. Can be formed. In other words, when a resist print that is the same as the copper foil pattern 13 is provided between the lands 12, the resist prints protrude from the upper surface of the lands 12 by the amount of the resist print.

FIG. 3 is a cross-sectional view in which the cream solder 4 is applied to the lands 12 of the printed circuit board 11. As described above, since the cream solder 4 accumulates in the recess 16, it does not drop.

FIG. 4 is a sectional view in which the lands 12 and the electrodes 7 are soldered with the cream solder 4. In this manner, since the land 12 protrudes by the amount corresponding to the double resist of the resists 14 and 15, the solder 4 sufficiently wraps between the land 12 and the electrode 7 to perform strong soldering.

When an electronic device is constructed by mounting the chip component 3 on the printed circuit board 11, the periphery of the land 12 of the printed circuit board 11 constituting the electronic device is surrounded by a concave portion 16 formed by resist printing. Because there is solder 4
Does not accumulate in this recess 16 and flow out. Therefore, even if a pattern is provided near the land 12, there is no short circuit. In addition, since the solder 4 accumulates in the recess 16, the contact area of the chip component 3 with the electrode 7 increases, the soldering strength increases, and reliable soldering can be performed.

Further, since the copper foil pattern 13 is provided between the lands 12 of the printed circuit board 11 constituting the electronic apparatus, the space between the lands 12 is convex from the upper surface of the lands 12. Therefore, a gap is formed between the electrode 7 and the land 12,
Since this gap is filled with the solder 4, the electrode 7 and the land 1
An electronic device formed of the printed circuit board 11 having a large bonding area between the two and having strong bonding can be obtained.

[0026]

As described above, according to the present invention, since the periphery of the land is surrounded by the concave portion formed of the insulator, the solder does not collect in the concave portion and flow out. Therefore, even if a pattern is provided near this land, there is no short circuit. Also, since the solder collects in the recesses, the contact area with the electrodes of the surface mount component increases,
Soldering strength is increased, and reliable soldering can be performed.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a printed circuit board according to an embodiment of the present invention.

FIG. 2 is a plan view of a main part of the same.

FIG. 3 is a cross-sectional view of the main part, to which cream solder is applied.

FIG. 4 is a cross-sectional view of a main part with the chip component mounted thereon.

FIG. 5 is a perspective view of a main part of a conventional printed circuit board.

FIG. 6 is a sectional view of a main part of the same, where cream solder is applied;

FIG. 7 is a cross-sectional view of a main part, in which a chip component is mounted.

[Explanation of symbols]

 11 Printed Circuit Board 12 Land 13 Copper Foil Pattern 14 Green Resist Printing 15 Black Resist Printing 16 Concave

Claims (10)

[Claims] 1. A printed circuit board on which a surface-mounted component is mounted, and a land provided on the printed circuit board and to which electrodes of the surface-mounted component are reflow-soldered. Printed circuit board provided on the bottom surface of the recessed portion. 2. The printed circuit board according to claim 1, wherein a copper foil pattern is provided around the land and a resist print is provided so as to cover the copper foil pattern. 3. The printed circuit board according to claim 1, wherein a resist print is provided around the land, and a second resist print is further provided on the resist print. 4. The printed circuit board according to claim 3, wherein the second resist printing is black. 5. The printed circuit board according to claim 4, wherein the second resist printing is slightly larger than the outer shape of the surface mount component. 6. An electronic device using the printed circuit board, wherein the surface-mounted component is mounted on one of the printed circuit boards according to claim 1. 7. A printed circuit board on which a surface-mounted component is mounted, and a land provided on the printed circuit board and to which an electrode of the surface-mounted component is reflow-soldered. Printed circuit board with a convex shape from the land. 8. The printed circuit board according to claim 7, wherein a copper foil pattern is provided between both lands of the surface mount component separately from these lands, and a resist print is provided so as to cover the copper foil pattern. 9. The printed circuit board according to claim 8, wherein the lands are provided on the bottom surfaces of the recesses formed by resist printing around the lands. 10. An electronic device using the printed circuit board, wherein the surface-mounted component is mounted on any one of the printed circuit boards according to claim 7.