JPH0722653A - Molding method of electronic component mounted on substrate - Google Patents

Abstract

PURPOSE:To enable forming high quality resin coated layer for an electronic component, especially an LED chip, mounted on a printed board or a substrate of a display panel or the like. CONSTITUTION:In a molding method of electronic component wherein a resin molding layer 3 is molded so as to surround an electronic component 2 and its substrate rear part in one-body, via through holes 5 of a substrate 1 which are arranged in the vicinity of the electronic component 2 like an LED chip mounted on the substrate 1, the injection gate 7 of a metal mold is arranged to face the surface 1a of the substrate in the vicinity of a cavity 4a on the electronic component mounting side. After the flow of material resin 6 injected from the gate 7 is once made to collide against the surface 1a of the substrate, the resin is made to flow into the cavity 4a on the electronic components mounting side.

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 on the electronic component mounted on the substrate. It is about the method.

[0002]

2. Description of the Related Art Conventionally, there is known a method of integrally molding an electronic component mounted on a substrate with the substrate. As an example of the electronic component, FIG. 2 shows an L mounted on a printed circuit board.
It is sectional drawing which shows the conventional molding method with respect to an ED chip typically. As shown in the figure, according to the conventional molding method, L mounted on one surface 11 a of the printed circuit board 11 is used.
An upper die 4A provided with a pair of through holes 5a and 5b for the printed board 11 near the ED chip 2 and provided with a predetermined lens-shaped cavity 4a for the LED chip 2.
And a lower mold 4B having a cavity 4b corresponding to the cavity 4a on the other surface 11b side and serving as a pool of molten metal.
A method of enclosing the LED chip 2 together with the printed circuit board 11 and injecting the synthetic resin 6 for molding from the cavity 4b side and guiding it through the through hole 5 into the lens-shaped cavity 4a for integral molding. Is.

[0003]

However, according to the conventional molding method, the resin 6 is applied from the back side of the printed circuit board as described above.
Since 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 in the effective part of the lens,
A linear unevenness (weld line) w is generated, which causes problems such as poor light transmission characteristics and poor appearance. Further, in contrast to the above method, when the resin is directly injected from the cavity 4a side, the resin 6 strongly hits the wall surface of the cavity 4a, and the trace of the resin flow (flow mark) that remains linearly in the effective portion of the lens is also obtained. ) Or the material becomes a string and is filled while buckling, and a string-like crushed surface structure (jetting) occurs, which causes the same problem as described above.

An object of the present invention is to solve the above problems and to mount an electronic component mounted on a substrate such as a printed circuit board or a display panel,
In particular, it is 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 thereof are passed through a through hole of the substrate provided near the electronic component such as an LED chip mounted on the substrate. A method of molding an electronic component, comprising molding a resin coating layer 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 flow of the material resin injected from the gate collides with the substrate surface once, the cavity on the electronic component mounting side It is a method characterized in that it is made to flow into.

The present invention will be described in more detail below. Figure 1
FIG. 4 is a cross-sectional view schematically showing a molding method according to the present invention when an LED chip is taken as an example. As shown in the figure, the molding method of the present invention is the LED mounted on the substrate 1.
By the molding method of the LED chip 2 in which the resin coating layer 3 is molded so as to integrally surround the LED chip 2 and the back surface portion 2b of the substrate through the through hole 5 of the substrate 1 provided in the vicinity of the chip 2. Therefore, the injection gate 7 is provided toward the substrate surface 1a in the vicinity of the cavity 4a on the LED chip mounting side, and the flow of the material resin 6 injected from the gate 7 is once collided with the substrate surface 1a. The method is characterized in that it is made to flow into the cavity 4a on the mounting side of No. 2.

As the electronic parts to which the molding method of the present invention is applied, in addition to the above LED chips, coils, resistors,
The present invention can be applied to various LSIs and the like, which can be molded by a single component. 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 protection.

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 circuit board as described above. In consideration of the influence on the passage, it is preferable to provide it at a position at least about 1 to 2 mm away from the end of the cavity. In some cases, the structure may be such that after filling one cavity, the resin flow path is extended from that cavity and the adjacent cavity is filled.

According to the present invention, the resin flow path 8 (hereinafter, this resin flow path is referred to as "runner") 8 generated between the gate and the cavity may be left on the substrate as a product or may be removed. It may be. The runner 8 preferably faces the cavity along the surface of the substrate with the substrate surface 1a as a part of the wall of the runner, but may be separated from the substrate after the collision with the substrate depending on the purpose. Good. The route from the gate of the runner 8 to the cavity is preferably formed so as to have the shortest course except that it bypasses an obstacle such as a circuit on the substrate. However, due to shrinkage of the resin or deformation of the lens due to sink marks, etc. In consideration of such a problem, a simple straight route may be avoided, and a runner route may be bent as many times as desired. The cross-sectional shape of the runner 8 may be a known shape such as a semicircle having the substrate as the bottom surface, a trapezoid, or the like, if necessary, or a circle, if necessary. The radial cross-sectional area of the runner 8 depends on various conditions such as the type of 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. Although the optimum value is determined, the cross-sectional area may be continuously changed from the gate toward the cavity to control the flow velocity, 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 side after filling the mounting side. . In addition, as a special example other than the above, a runner that does not provide a runner for a specific path and coats a part or the whole of the surface of the mounting-side board may be used.

[0010]

According to the molding method of the present invention, when the resin coating layer is molded on the electronic component mounted on the substrate, the flow of the material resin to be injected into the cavity is first set on the substrate surface on the LED chip mounting side. By injecting 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 maintaining the injection pressure into the cavity.

[0011]

EXAMPLES The present invention will be specifically described below based on examples. Needless to say, the present invention is not limited to this. In this example, an LED chip was mounted on a substrate that became a display panel, and a resin coating layer was formed using the molding method of the present invention, and the quality of the effective portion of the lens was confirmed. Polycarbonate is used as a material resin for molding, and as shown in FIG. 1, the material resin is injected from a gate 7 provided between the two cavities C1 and C2 at an exit pressure of the extruder of 1500 kgf / cm ² . Then, the LED chip 2 and the back surface portion of the substrate thereof were integrally molded through the penetrating item 5 to obtain an LED lighting device having a colorless and transparent lens coating layer. When the quality of the lens part of the LED lighting device obtained by this experiment was evaluated, no weld lines, flow marks, jetting, etc. were found in the effective part, and both the front and back sides were 100% filled. It was confirmed that the quality was good. By the above experiment, the molding method of the present invention, the molding of the electronic component mounted on the substrate, in particular,
It was confirmed that it is effective for forming the lens of the LED chip.

[0012]

As described above, according to the molding method of the present invention, when an electronic component mounted on a substrate is molded,
Since the impact force when the material resin flows into the cavity of the mounting side is relaxed and the material resin is injected from the component mounting side, the weld line, the flow mark, A high-quality resin coating layer can be obtained without forming defects such as jetting. INDUSTRIAL APPLICABILITY The molding method of the present invention is particularly effective for molding an LED chip mounted on a substrate, and can provide an LED illuminator with excellent light-transmitting properties and appearance on the lens surface.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing a molding method according to the present invention when an LED chip is taken 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 that occurs in the mounting-side coating layer in the conventional molding method.

[Explanation of symbols]

 1 substrate 2 LED chip 3 resin coating layer 4a mounting side cavity 4b back side cavity 5 through hole 6 material resin 7 gate 8 runner

Claims (2)

[Claims] 1. An electronic device in which a resin coating layer is formed so as to integrally surround the electronic component and the back surface portion of the substrate of the component through a through hole of the substrate provided in the vicinity of 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 in the vicinity of a cavity on an electronic component mounting side, and a flow of a material resin injected from the gate is temporarily collided with the substrate surface. And a method of molding an electronic component, characterized in that it is made to flow into a cavity on the electronic component mounting side. 2. The electronic component is an LED chip.
The described molding method.