JP3447139B2 - Chip type light emitting diode - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip type light emitting diode, and more particularly to a chip type light emitting diode in which LED elements are mounted so as to emit light in parallel to a mounting substrate of the chip type light emitting diode.

[0002]

2. Description of the Related Art Conventionally, as the chip type light emitting diode 1 of this type, ones shown in FIGS. 4 and 5 are known (see Japanese Utility Model Laid-Open No. 4-65465). In this chip type light emitting diode 1, electrodes 3 and 4 are formed by plating wiring on both sides of a rectangular parallelepiped plastic insulating substrate 2. These electrodes 3 and 4 are formed in a substantially U-shaped cross section so as to wrap around the front and rear sides of the insulating substrate 2, and the LED element 5 is fixed to the upper surface of the electrode 3 on one side by silver paste or the like. Further, the surface of the transparent resin 6
The structure is sealed by.

The chip type light emitting diode 1 having such a structure is mounted so as to emit light in parallel to the mounting substrate 7, and is formed on the mounting substrate 7 as shown in FIG. 5, for example. The solder paste 10 is applied on the wiring patterns 8 and 9 in advance, and the end surfaces 11 and 12 of the electrodes 3 and 4 on the both side surfaces are placed on the wiring pastes 8 and 9, respectively, and the end surfaces 11 of the electrodes 3 and 4 are placed on the wiring patterns 8 and 9. , 12 were soldered to fix the chip type light emitting diode 1.

[0004]

By the way, in the chip type light emitting diode 1 having the above-mentioned conventional structure, there is a possibility that soldering failure may occur when mounted on the mounting substrate 7. As shown in FIG. 5, the plating wiring forming the electrodes 3 and 4 is the copper foil layer 18 and the nickel plating layer 1.
9. It is composed of three layers of gold plating layer 13, and its end face 1
Since the copper foil layer 18 and the nickel plating layer 19 are exposed at 1 and 12, the solder wettability deteriorates, and the solder cannot flow from the end faces 11 and 12 of the electrodes 3 and 4 to the surface side of the gold plating layer 13. This is because there is a risk that solder may not be sufficiently applied.

That is, in the process of manufacturing the chip type light emitting diode 1, as shown in FIG. 6, the plastic insulating substrate 2 is obtained by taking a large number of pieces from a large substrate 14 or a large number of pieces using a plastic molding die, and plating wiring. After the formation of the electrodes 3 and 4 by the above, the mounting of the LED element 5, and the sealing process by the transparent resin 6 are completed, it is cut along a cut line 15 by a dicing machine or the like, and divided into individual chips. . As a result, when mounted on the mounting substrate 7 as shown in FIG. 4, cut surfaces appear on the upper surface 16 and the lower surface 17 of the chip type light emitting diode 1, and similarly, the end surfaces 11 of the electrodes 3 and 4 are formed. , 12 also shows the cross section of the plated wiring. Then, the underlying copper foil layer 18 and the nickel plating layer 1 constituting the plated wiring
9 and the cross section of the gold plating layer 13 of the outer material are exposed,
In particular, since the gold plating layer 13 is very thin, the contact area between the cross section of the gold plating layer 13 and the solder is small, and the wettability of the solder may be significantly reduced.

Therefore, the present invention improves the wettability of the solder when soldering the chip type light emitting diode onto the mounting substrate, and makes it easy for the solder to reach the surface side of the electrode, thereby eliminating defective soldering. is there.

[0007]

That is, in a chip type light emitting diode according to the present invention, an LED element is mounted on an insulating substrate having electrodes formed by plated wiring, and the surface of the LED element is made of a transparent resin. The end face of the electrode to be soldered on the wiring pattern of the mounting substrate is plated again to cover the end face of the plated wiring.

Further, the plated wiring forming the electrodes of the chip type light emitting diode according to the present invention is characterized in that the base is a layer of nickel or copper and nickel, and the outer material is gold or silver.

[0009]

According to the above-mentioned means, when the solder paste is applied on the wiring pattern of the mounting substrate and the end surface of the electrode of the chip type light emitting diode is placed thereon, the plating and the solder coated on the end surface of the electrode are mounted. The contact area with the paste increases. As a result, the wettability of the solder is improved, the solder is more likely to reach the surface side of the electrode, the solder is ridden well, and the joining is ensured.

[0010]

Embodiments of the chip type light emitting diode according to the present invention will be described in detail below with reference to the accompanying drawings. 1 to 3 show an embodiment of a chip type light emitting diode 20 according to the present invention. Basically, similar to the conventional one, electrodes 3 and 4 are formed by plating wiring on both sides of a rectangular parallelepiped plastic insulating substrate 2. The electrodes 3 and 4 are formed so as to wrap around to the front and rear sides, and the LED element 5 is fixed to the upper surface of the electrode 3 on one side by a conductive adhesive such as silver paste. The LED element 5 and the electrode 4 on the other side are electrically connected by a wire 21 such as gold or aluminum. Further, the surface of the LED element 5 is protected by a translucent resin 6 to protect the LED element 5 and the wire 21. It has a sealed structure. Further, the plating wirings for forming the electrodes 3 and 4 on both side surfaces are also composed of three layers as in the above-mentioned example, and the copper foil layer 18 and the nickel plating layer 19 are formed on the base,
A thin gold plating layer 13 is applied to the outer material.

Also in the manufacturing process of the chip type light emitting diode 20 having the above-mentioned structure, a large number of pieces are picked up from a large substrate 14 as shown in FIG. Since the chips are cut into individual chips along the cut line 15 by the above, the cut surfaces appear on the upper surface 16 and the lower surface 17 of the chip type light emitting diode 20 in a state where the chips are mounted on the mounting substrate 7. As a result, the end faces 11 of the electrodes 3 and 4,
The section of the plated wiring also appears in 12, and the sections of the copper foil layer 18 and the nickel plated layer 19 which are hard to be soldered appear.

In this embodiment, the end faces 11, 1 of the electrodes 3, 4 are
2 is gold-plated again to cover the end faces of the copper foil layer 18 and the nickel-plated layer 19 with gold-plated films 22 and 23,
It improves the wettability of the solder. Gold plating films 22 and 23 are formed only on the end faces of the copper foil layer 18 and the nickel plating layer 19, respectively.
There is a substitution type electroless plating method as a method of attaching. In the above-described embodiment, this is because the copper foil layer 18 and the nickel plating layer 19 are melted and the atoms of copper and nickel are exchanged with the atoms of gold, and the end faces of the copper foil layer 18 and the nickel plating layer 19 are changed as shown in FIG. The gold-plated films 22 and 23 are attached only to the above, and the gold-plated layer 13 forming the outer surface of the electrode and its end surface, and the non-metal part such as the plastic insulating substrate 2 and the translucent resin 6 are not attached with the above gold-plated film. .

Therefore, the end faces 1 of the electrodes 3 and 4 are thus formed.
When the gold-plated films 22 and 23 are formed again on the electrodes 1 and 12, since the cross sections of the copper foil layer 18 and the nickel-plated layer 19 that form the plated wiring are covered with the gold-plated films 22 and 23, the electrodes 3, 4 are formed. The entire end surfaces 11 and 12 of the above are formed by gold plating. Therefore, when the chip type light emitting diode 20 is mounted on the mounting substrate 7, the solder paste 10 applied on the wiring patterns 8 and 9 and the end surfaces of the electrodes 3 and 4 are formed as shown in FIG. Since the contact area with the end faces of the gold-plated films 22 and 23 and the gold-plated layer 13 is increased, the wettability of the solder is remarkably improved, and the solder easily wraps around the surface side of the electrodes 3 and 4, so that the solder can be ridden. And the joining is reliable.

The gold plating can be performed not only by electroless plating but also by electrolytic plating. In this electrolytic plating method, the plastic insulating substrate 2 and the light-transmissive resin 6 are not gold-plated, but not only the end surfaces 11 and 12 of the electrodes 3 and 4 but also the gold-plated layer 13 on the outer surface are gold-plated. Become. Further, in the above embodiment, the case where the end faces 11 and 12 of the electrodes 3 and 4 are plated with gold has been described, but the present invention is not limited to gold plating, and is excellent in solder wettability such as tin plating and solder plating. Of course, the present invention includes the present invention. Further, in the above-described embodiment, the case where the base of the plated wiring is the copper foil layer 18 and the nickel plated layer 19 and the outer material is the gold plated layer 13 has been described. However, in the present invention, the kind of metal forming the lower layer or the outer material layer and The number of layers is not limited in any way, and is also applicable to the case where only one of copper and nickel is used as the base and silver is used as the outer material.

[0015]

As described above, according to the chip type light emitting diode of the present invention, since the end surface of the electrode by the plated wiring is covered with plating again, the chip type light emitting diode is mounted on the mounting substrate. When soldering, the wettability between the above-mentioned plating and the solder is improved, the solder easily goes around from the end face of the electrode to the surface side, the solder gets on well, and the solder and the electrode are securely joined together. It does not cause soldering failure.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a chip type light emitting diode according to the present invention.

FIG. 2 A in FIG. 1 showing electrodes of a chip type light emitting diode
FIG.

FIG. 3 is a cross-sectional view taken along the line AA in FIG. 1, showing a state where solder is attached to the end faces of the electrodes of the chip type light emitting diode.

FIG. 4 is a perspective view showing an example of a conventional chip type light emitting diode.

FIG. 5B in FIG. 4 showing electrodes of a chip type light emitting diode.
It is a -B line sectional view.

FIG. 6 is a front view showing an insulating substrate for taking a large number of chip type light emitting diodes.

[Explanation of symbols]

2 insulating substrate 3 electrodes 4 electrodes 5 LED element 6 Translucent resin 7 Mounting board 8 wiring patterns 9 wiring patterns 10 Solder paste 11 Electrode end face 12 electrode end face 20 chip type light emitting diode 22 Gold plated film 23 Gold plated film

Claims (2)

(57) [Claims] 1. An LED element is mounted on an insulating substrate on which electrodes are formed by plating wiring, the surface of the LED element is sealed with a translucent resin, and soldering is performed on the wiring pattern of the mounting substrate. A chip type light emitting diode in which an end surface of a plated wiring appears on an end surface of the electrode, wherein the end surface of the electrode is plated to cover the end surface of the plated wiring. 2. The chip type light emitting diode, wherein the plated wiring forming the electrode has a base layer of nickel or a layer of copper and nickel and a surface material of gold or silver.