JPH05145121A - Packaging structure of light emitting diode - Google Patents

Abstract

PURPOSE:To reduce packaging cost of light emitting diodes, and also, enhance emission efficiency of light emitting devices. CONSTITUTION:An MCB base 10, where a chip mounting recessed part 11 is formed, is injection-molded with thermoplastics. A wiring pattern 12 and an LED bare chip 13 formed on the top of the base 10 are die-bonded substantially in the central part of the recessed par 11 by way of Ag paste or the like. An Au wire 14 which connects the LED chip 13 to the wiring pattern 12, transparent sealing resin 15 and the like are formed in the shape of a convex lens by injecting resin whose quantity exceeds the volume of the chip mounting recessed part 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting diode mounting structure.

[0002]

2. Description of the Related Art Conventionally, a light emitting diode (LED) is mounted on a printed wiring board by using a pre-packaged one, which is inserted into a through hole of the board or soldered on the surface depending on its form. I was doing it.

FIG. 2 shows a packaged light emitting diode, in which 1 is an LED chip, 2 is a stem, 3 is an Au wire, 4 is a lead terminal, and 5 is a transparent resin. FIG. 3 shows a state in which such a light emitting diode is mounted on the printed wiring board 6, and the lead terminal 4 is soldered to the conductor 7.

Further, in a recent example, as shown in FIG.
The ED bare chip 1 is directly die-bonded to the printed wiring board 6, the Au wire 3 is bonded, and then the transparent resin 5
Some are sealed with. Note that FIG. 7A shows the case where the sealing frame 8 is used, and FIG. 8B shows the case where the sealing frame is not used.

[0005]

However, the LED
For the device shown in Figure 2, the package cost is
If the bare chip cost is more than doubled and the bare chip is directly mounted on the printed wiring board, then FIG.
As shown in FIG. 5, it is necessary to provide the sealing frame 8 for preventing resin flow, and in any case, there is a problem in reducing the LED mounting cost.

When the LED is directly mounted on the printed wiring board, the luminous efficiency is poor because the reflector is not provided.
As shown in (b), there is a case where a thixotropic property of the resin 5 is used to maintain the sealing shape without providing a sealing frame, and a convex lens is configured to have directivity to increase the apparent light amount. In this case, in order to keep the shape of the resin 5 constant, it is necessary to control not only the amount of resin but also the coating position and temperature.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a mounting structure capable of reducing the mounting cost of an LED and improving the luminous efficiency of the LED. is there.

[0008]

In order to solve the above problems, the present invention has a structure in which a bare chip of a light emitting diode is directly mounted on a molded circuit board (hereinafter abbreviated as MCB) using a thermoplastic resin. And the MCB
In addition to forming a chip mounting recessed portion in advance, a wiring pattern is formed on the entire surface of the recessed portion except for insulating required portions, and a bare chip of a light-emitting diode is die-bonded and wire-bonded to the wiring pattern, and the recessed portion has a volume greater than that of the recessed portion. It is characterized in that a large amount of transparent resin is injected to make the upper surface a convex lens shape.

[0009] Here, MCB (mold interconnection device; MI) using a thermoplastic resin is used.
(Also called D) is used as a structural member in recent years for the purpose of downsizing and thinning electronic circuit application products and cost reduction. For example, the case of the product itself is composed of MCB, At the same time, an electric path is formed inside so that the case and the printed wiring board can be integrated.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the present invention. In the figure, 10 is an MC in which a chip mounting recess 11 is formed.
The base of B is injection molded with a thermoplastic resin. The resin used in this example is called liquid crystal polymer and is Vectra C810 (manufactured by Polyplastics Co., Ltd.). Reference numeral 12 denotes a wiring pattern formed on the upper surface of the base 10 (usually Cu plating), which is Ni-plated or Au-plated for wire bonding in a later step. Reference numeral 13 is a bare LED chip, which is the recess 11
It is die-bonded at approximately the center of the substrate with Ag paste or the like. An Au wire 14 connects the LED chip 13 and the wiring pattern 12. Reference numeral 15 is a transparent sealing resin, which is filled with a resin amount larger than the volume of the chip mounting recess 11 to form a convex lens shape on the upper surface.

With this configuration, the wiring pattern 12 serves as a reflection plate of the LED chip 13, and the convex lens effect of the sealing resin 15 makes it possible to increase the apparent light amount of the LED. Further, since the chip mounting recess 11 is formed in advance, the resin flow preventing sealing frame 8 as shown in FIG. 3 (a) becomes unnecessary, and the cost can be reduced.

[0012]

As described above, according to the present invention, a chip mounting recess is formed in the MCB in advance, and a wiring pattern is formed on the entire surface of the recess except for a necessary insulating portion, and a bare chip of a light emitting diode is formed on the wiring pattern. By die-bonding and wire-bonding, and by injecting a transparent resin in an amount larger than the volume of the concave portion into the concave portion to form a convex lens shape on the upper surface, the LED mounting cost can be reduced, and moreover,
It is possible to provide a mounting structure that can improve the luminous efficiency of the LED.

[Brief description of drawings]

1A and 1B show an embodiment of the present invention, in which FIG. 1A is a top view and FIG. 1B is a sectional view.

FIG. 2 is a perspective view showing a conventional packaged light emitting diode.

FIG. 3 is a partial cross-sectional front view showing a state in which the light emitting diode is mounted on a printed wiring board.

FIG. 4 shows a conventional example in which an LED bare chip is mounted on a printed wiring board, (a) shows a case where a sealing frame is used, and (b) shows a case where the sealing frame is not used.

[Explanation of symbols]

 10 Base of Molded Circuit Board 11 Recess for Chip Mounting 12 Wiring Pattern 13 LED Bare Chip 14 Au Wire 15 Transparent Resin

Claims (1)

[Claims] 1. A structure in which a bare chip of a light emitting diode is directly mounted on a molded circuit board using a thermoplastic resin, wherein a recess for mounting a chip is formed in advance on the molded circuit board and the entire surface of the recess is formed. A wiring pattern is formed on the wiring pattern except for a necessary insulating portion, a bare chip of a light emitting diode is die-bonded to the wiring pattern and wire bonding is performed, and a transparent resin in an amount larger than the concave portion volume is injected into the concave portion to form a convex lens shape on the upper surface. A mounting structure of a light-emitting diode characterized by the above.