JP2739279B2 - Molding method for electronic components mounted on a substrate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for molding an electronic component mounted on a substrate, and more particularly to a mold capable of forming a high-quality resin coating layer without a weld line or the like on an electronic component mounted on a substrate. It is about the method.

[0002]

2. Description of the Related Art Conventionally, there has been known a method of integrally molding an electronic component mounted on a substrate with the substrate. FIG. 2 shows an example of the electronic component, which is mounted on a printed circuit board.
It is sectional drawing which shows the conventional molding method with respect to ED chip typically. As shown in FIG. 1, the conventional molding method uses an L-mount mounted on one surface 11 a of a printed circuit board 11.
In the vicinity of the ED chip 2, a pair of through holes 5a, 5b is provided for the printed board 11, and an upper die 4A having a predetermined lens-shaped cavity 4a for the LED chip 2.
And a lower mold 4B having a cavity 4b serving as a pool corresponding to the cavity 4a on the other surface 11b side,
The LED chip 2 is surrounded together with the printed circuit board 11, and the synthetic resin 6 for molding is injected from the cavity 4 b side, and the LED chip 2 is guided into the lens-shaped cavity 4 a through the through hole 5 and integrally molded. It is.

[0003]

However, in the conventional molding method, as described above, the resin 6 is removed from the back side of the printed circuit board.
And the resin 6 flows into the lens side cavity 4a through the two through holes 5a and 5b.
As shown in FIG. 3, the resin merges at the effective portion of the lens,
Linear unevenness (weld line) w occurs, which causes problems such as a defect in light transmission characteristics and a defect in appearance. Further, when the resin 6 is directly injected from the lens cavity 4a side, the resin 6 strongly hits the wall surface of the cavity 4a, and the trace of the resin flow (flow mark) which remains in the effective portion of the lens in a linear manner. ) Or the material is string-shaped and buckled and filled, resulting in a string-like crushed surface texture (jetting), which causes the same problem as described above.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide an electronic component mounted on a substrate such as a printed circuit board or a display panel.
In particular, it is an object of the present invention to provide a molding method capable of forming a high quality resin coating layer on an LED chip.

[0005]

According to the method of molding an electronic component of the present invention, the electronic component and the substrate are passed through a through hole of the substrate provided near an electronic component such as an LED chip mounted on the substrate. A method of molding an electronic component in which a resin coating layer is molded so as to integrally surround a back surface portion,
The injection gate of the molding die is provided toward the substrate surface near the cavity on the electronic component mounting side, and after the material resin injected from the gate once collides with the substrate surface, the cavity on the electronic component mounting side is formed. This is a method characterized by flowing into

Hereinafter, the present invention will be described in more detail. FIG.
FIG. 2 is a cross-sectional view schematically illustrating a molding method according to the present invention in the case of taking an LED chip as an example. As shown in the figure, the molding method of the present invention uses the LED mounted on the substrate 1.
A method of molding the LED chip 2 in which the resin coating layer 3 is molded so as to integrally surround the LED chip 2 and the rear surface portion 2b of the substrate through the through hole 5 of the substrate 1 provided near the chip 2. Then, the injection gate 7 is provided toward the substrate surface 1a near the cavity 4a on the LED chip mounting side, and once the flow of the material resin 6 injected from the gate 7 collides with the substrate surface 1a, This method is characterized by flowing the fluid into the cavity 4a on the mounting side of No. 2.

The electronic parts to which the molding method of the present invention is applied include coils, resistors,
The present invention can be applied to all types of LSIs and other components that can be molded alone. Also, for contact parts such as relays, as a mold without cracks on the mounting side,
It can be an effective sealing method for explosion proof.

The position of the gate 7 with respect to the cavity 4a may be any position as long as the resin flow can once collide with the printed board as described above. In consideration of the influence on the road, it is preferable to provide the cavity at least about 1 to 2 mm away from the end of the cavity. In some cases, after filling one cavity, the resin flow path may be extended from that cavity to fill the next cavity.

According to the present invention, a resin flow path (hereinafter referred to as a “runner”) 8 formed between the gate and the cavity may be left as a product on the substrate or may be removed. There may be. The runner 8 preferably has a mode in which the substrate surface 1a is part of the wall of the runner and is directed toward the cavity along the substrate surface. However, depending on the purpose, the runner 8 separates from the substrate after collision with the substrate. Is also good. The path from the gate of the runner 8 to the cavity is preferably formed so as to have the shortest course except for bypassing an obstacle such as a circuit on the substrate. In consideration of such a problem, a simple straight path may be avoided, and a runner path may be bent a desired number of times. The cross-sectional shape of the runner 8 may be a known shape such as a semicircle or a trapezoid having the substrate as the bottom surface when the substrate normally contacts the substrate, or a circular shape as necessary. The cross-sectional area in the radial direction of the runner 8 depends on various conditions such as the type of the material resin, the resin temperature, the mold temperature, the injection pressure, the injection speed, the injection time, and the like, and the appearance when the product remains as a product. Although the optimum value is determined, the cross-sectional area may be continuously changed from the gate to the cavity to control the flow rate, the pressure, and the like. The position where the runner 8 merges with the cavity is preferably determined in consideration of the positional relationship with the through hole so that the resin flow in the cavity flows into the back surface after filling the mounting side. . Further, as a special example other than the above, a runner that coats a part or the whole of the mounting-side substrate surface without providing a runner of a specific path may be used.

[0010]

According to the molding method of the present invention, when a resin coating layer is formed on an electronic component mounted on a substrate, the flow of material resin injected into the cavity is first applied to the substrate surface on the LED chip mounting side. By injecting the resin into the cavity on the mounting side after the collision, it is possible to reduce only the impact force when the material resin flows into the cavity while keeping the injection pressure in the cavity.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments. It goes without saying that the present invention is not limited to this. In this example, an LED chip was mounted on a substrate serving as a display panel, and a resin coating layer was formed on the substrate using the molding method of the present invention, and the quality of the effective portion of the lens was confirmed. As shown in FIG. 1, polycarbonate is used as a material resin for molding, and as shown in FIG. 1, the above material resin is injected from a gate 7 provided between two cavities C1 and C2 at an outlet pressure of an extruder of 1500 kgf / cm ² . Then, the LED chip 2 and the rear surface portion of the substrate were integrally molded through the through hole 5 to obtain an LED lighting device having a colorless and transparent lens covering layer. When the quality of the lens portion of the LED lighting device obtained by this experiment was evaluated, no effective weld line, flow mark, jetting, etc. were found in the effective portion, and 100% of both sides were filled. It was confirmed that the quality was good. By the above experiments, the molding method of the present invention is a method of molding an electronic component mounted on a substrate, in particular,
It was confirmed that it was effective for forming a lens of an LED chip.

[0012]

As described above, according to the molding method of the present invention, when molding an electronic component mounted on a substrate,
In order to reduce the impact force when the material resin flows into the cavity on the mounting side and to inject the material resin from the component mounting side, weld lines, flow marks, A high-quality resin coating layer can be obtained without forming defects such as jetting. The molding method of the present invention is particularly effective for molding an LED chip mounted on a substrate, and can provide an LED lighting device excellent in light transmission and appearance on a lens surface.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing a molding method according to the present invention when an LED chip is used as an example.

FIG. 2 is a cross-sectional view schematically showing a conventional molding method for an LED chip mounted on a printed board.

FIG. 3 is a cross-sectional view schematically showing a molding defect occurring in a coating layer on a mounting side in a conventional molding method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 LED chip 3 Resin coating layer 4a Mounting side cavity 4b Backside cavity 5 Through hole 6 Material resin 7 Gate 8 Runner

Claims (2)

(57) [Claims] 1. An electronic device, comprising: a resin coating layer formed so as to integrally surround the electronic component and a rear surface portion of the component through a through hole of the substrate provided near the electronic component mounted on the substrate. A method of molding a component, wherein an injection gate of a molding die is provided toward a substrate surface near a cavity on an electronic component mounting side, and after a flow of a material resin injected from the gate once collides with a substrate surface, And molding the electronic component into a cavity on the electronic component mounting side. 2. The electronic component is an LED chip.
The molding method as described above.