JPH0653553A - Resin sealed structure for led - Google Patents

Abstract

PURPOSE:To retard exfoliation of epoxy resin from a printed board. CONSTITUTION:A printed board 11 is fixed to the back face side of a light reflecting case 10 having a hole 10a for fixing an LED element and 8 pair of bonding pads 12, 13 are provided on the substrate 11 in the hole 10a while a LED element 14 is fixed to the pad 12. The LED element 14 and the pad 13 are connected through a wire 15 and the hole 10a is sealed with epoxy resin 16 thus providing the pads 12, 13 with a complex pattern for increasing adhesion area between the epoxy resin 16 and an exposed face 11a of the substrate.

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 resin-sealed structure in which a light emitting diode element is sealed with a resin.

[0002]

2. Description of the Related Art As a resin-sealed structure for a light-emitting diode, there are, for example, those shown in FIG. 5 (plan view) and FIG. 6 (cross-sectional view taken along the line CC in FIG. 5). In this structure,
Light-emitting diode element (LED element) in the light reflection case 30
A mounting hole 30a is formed so as to penetrate therethrough, and in this example, the hole 30a has a truncated quadrangular pyramid shape and one side (back side).
To the other side (front side) in a radial manner. A printed circuit board 31 is fixed to the back side of the light reflection case 30 so as to close one opening of the hole 30a.
A pair of square-shaped bonding pads 32 and 33 are formed on the printed circuit board 31 in a.

The pads 32 and 33 are gold-plated to improve the light reflectivity, and the pads 32 and 33 are provided with holes 30 to improve the reflection efficiency of the light from the LED element 34.
It is formed on almost all surfaces of the printed circuit board 31 appearing in a. The LED element 34 is die-bonded to the pad 32, and the LED element 34 and the pad 33 are bonded.
Are wire-bonded with wires 35. The hole 30 a including the pads 32 and 33, the LED element 34, and the wire 35 is sealed with an epoxy resin 36.

In this structure, the light from the LED element 34 is emitted from the surface of the hole 30a of the light reflection case 30 and the pads 32 and 3.
It is reflected by 3 and emitted from the hole 30a.

[0005]

However, in the above structure, the epoxy resin 36 and the printed circuit board 3 are used.
Since the contact area with 1 is small, that is, the surface 31a of the printed circuit board 31 is only slightly exposed between the pads 32 and 33 as shown by the intersecting line in FIG.
No. 6 has poor adhesion to the substrate surface 31a, and the substrate surface 31a
Easy to peel from Moreover, pad 3 with gold plating
Since the adhesiveness between 2, 33 and the epoxy resin 36 is not good, when the epoxy resin 36 is peeled from the substrate surface 31a, it is also immediately peeled from the pads 32 and 33. If the epoxy resin 36 is severely peeled off, the wire 35 is separated (wire open) from the LED element 34 and the pad 33, which causes a problem that the LED element 34 does not emit light.

Therefore, an object of the present invention is to provide a resin-sealed structure for a light-emitting diode in which the epoxy resin is difficult to peel off from the printed circuit board.

[0007]

In order to achieve the above object, a resin-sealed structure for a light-emitting diode according to the present invention has a complicated structure in which a contact area between an epoxy resin and a substrate is large in the conventional structure. The bonding pad has a different pattern. As a result, the exposed area of the substrate in the hole of the light reflection case is increased, the adhesion between the epoxy resin and the substrate is increased, and the epoxy resin is less likely to be peeled off from the substrate.

The pattern of the bonding pad is
Any pattern may be used as long as the contact area between the epoxy resin and the substrate is large, but a complicated pattern is preferable as much as possible in order to strongly adhere the epoxy resin to the substrate. However, the larger the exposed area of the substrate, the smaller the area of the bonding pad with light reflectivity,
Since the light reflection efficiency decreases, the light extraction efficiency with respect to the LED element deteriorates, and another problem such as light leakage occurs. Therefore, it is important to form the bonding pad in a pattern having an appropriate shape and size in consideration of adhesion and light reflectivity.

[0009]

EXAMPLES A resin-sealed structure for a light emitting diode according to the present invention will be described below based on examples. FIG. 1 is a plan view of a structure according to the embodiment, and FIG. 2 is a sectional view taken along line AA of FIG. This structure has basically the same structure as the conventional structure shown in FIGS. 5 and 6, but the pattern of the bonding pad is different. That is, the light reflection case 1
A pair of bonding pads 12 and 13 having a complicated pattern as shown in the drawing are formed on the portion of the printed circuit board 11 that appears in the LED element mounting hole 10a of 0.

An LED element 14 is die-bonded to one pad 12, and the LED element 14 is wire-bonded to the other pad 13 with a wire 15. Similarly, the hole 10a is sealed with the epoxy resin 16. It should be noted that the exposed surface (see the intersecting line portion in FIG. 1) 11a of the printed circuit board 11 which is not covered with the pads 12 and 13 is not provided with solder resist in order to improve the adhesion of the epoxy resin 16.

The printed circuit board 11 is generally made of an epoxy resin base material, for example, an epoxy resin containing a glass cloth base material having good adhesion to the epoxy resin 16, and therefore the pads 12, 13 having a complicated pattern as shown in the drawing. In this case, the adhesion between the widened exposed surface 11a of the printed board 11 and the epoxy resin 16 is improved, and the epoxy resin 16 is less likely to peel off from the board exposed surface 11a. Therefore, the open state of the wire 15 due to the peeling of the epoxy resin 16 does not occur, and the problem of non-light emission of the LED element 14 hardly occurs.

FIG. 3 is a plan view of a structure according to another embodiment.
A cross-sectional view taken along the line BB of FIG. 3 is shown in FIG. In this structure, since the pair of bonding pads 22 and 23 has an extremely small square shape,
The exposed surface 21a of the printed board 21 is considerably widened, and the adhesion between the epoxy resin 26 and the exposed board surface 21a is significantly improved. However, since the total area of the light-reflecting pads 22 and 23 is reduced, the reflection efficiency of the light from the LED element 24 is reduced, and the light emitted from the hole 20a becomes dark. From this, although it is excellent in preventing peeling of the epoxy resin, as an actual bonding pad,
The bonding pad having the pattern of complicated shape and size disclosed in the above embodiment is preferable.

[0013]

As described above, the resin-encapsulated structure for a light-emitting diode according to the present invention has a complicated pattern in which the bonding area between the epoxy resin and the substrate is large. Adhesion with the substrate is improved, the epoxy resin is difficult to peel from the substrate,
Defects such as non-emission of the LED element due to wire opening are reduced.

[Brief description of drawings]

FIG. 1 is a plan view of a structure according to an embodiment of the present invention.

2 is a cross-sectional view taken along line AA of the structure shown in FIG.

FIG. 3 is a plan view of a structure according to another embodiment of the present invention.

4 is a cross-sectional view of the structure shown in FIG. 3 taken along the line BB.

FIG. 5 is a plan view of a structure according to a conventional example.

6 is a cross-sectional view of the structure shown in FIG. 5 taken along the line C-C.

[Explanation of symbols]

 10, 20 Light reflection case 10a, 20a Hole 11, 21 Printed circuit board 11a, 21a Substrate exposed surface 12, 13, 22, 23 Bonding pad 14, 24 LED element 15, 25 Wire 16, 26 Epoxy resin

Claims (1)

[Claims] 1. A substrate is mounted on one side of a light reflection case having a hole for mounting a light emitting diode element, a pair of bonding pads is provided on the substrate in the hole, and a light emitting diode element is mounted on one bonding pad. In a resin-sealed structure of a light-emitting diode in which a light-emitting diode element and another bonding pad are wire-bonded and a hole is sealed with an epoxy resin, the bonding pad has a large contact area between the epoxy resin and the substrate. A resin-sealed structure for a light-emitting diode, which has such a complicated pattern.