JP3704451B2 - Manufacturing method of light emitting diode lamp - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
This invention relates to a substrate directly attached light emitting diode (LED) lamp, about the particular LED lamps to achieve a reduction in solder failure manufacture how.
[0002]
[Prior art]
The conventional LED lamp manufacturing method is mainly based on casting mold casting. The lead frame on which the LED is mounted is immersed in an epoxy resin full of the case, and the lead frame is molded with the epoxy resin. By doing so, an LED lamp is formed.
[0003]
In that case, when the lead frame is immersed in the epoxy resin, the epoxy resin crawls up to the base of the lead terminal due to surface tension. Therefore, as shown in FIG. 11, a resin swell 5 is necessarily formed at the base of the lead terminal 4 on the bottom surface of the epoxy resin 2 in the molded LED lamp 1.
[0004]
[Problems to be solved by the invention]
However, the conventional LED lamp manufacturing method has the following problems. That is, in the future, it is expected that the number of LED lamps directly attached to the substrate will increase with the progress of automatic mounting. By the way, when the LED lamp is directly attached to the board, the LED lamp 1 is pulled against the board 6 by the lead clinching force as shown in FIG.
[0005]
At that time, the bulge portion 5 of the resin at the base of the lead terminal 4 bites into the through hole 7 of the lead terminal 4 in the substrate 6 and closes the through hole 7. Then, the air in the gap between the through hole 7 of the substrate 6 and the lead terminal 4 is ejected to the solder 8 side due to thermal expansion after the solder bonding, and the blow hole is frequently generated in the solder 8 and the reliability is remarkably impaired. is there. For this reason, there is a problem that it is necessary to rework manually, and extra labor is required.
[0006]
Accordingly, an object of the present invention is to provide a soldering production how the LED lamps that can significantly reduce the failure rate of the blow hole.
[0007]
[Means for Solving the Problems]
To achieve the above object, the present invention is a lead frame L ED is mounted with formed by resin molding, an LED lamp provided with a protrusion on the bottom surface of the mold resin, the LED lamp formed by casting molding method In a manufacturing method, a mold case is used in which notch portions are provided at least at two locations facing each other on the inner wall of the resin injection port, and the mold resin is injected to a height near the lower end of the notch portion in the mold case. The lead frame is immersed in a mold resin in the mold case with a lead terminal positioned in the vicinity of the notch of the mold case.
[0008]
According to the said structure, the notch part is provided in the resin injection inlet inner wall of a mold case, and the surface of the inject | poured mold resin exists in the height of the lower end vicinity of the said notch part. Therefore, on the outer peripheral edge of the bottom surface of the molded resin of the molded LED lamp, a bulge portion and a non-bulge portion are formed on the inner wall surface of the mold case due to a difference in surface tension in the vertical direction acting on the mold resin. Is done.
[0009]
Furthermore, the lead terminal of the lead frame immersed in the mold resin is located in the vicinity of the notch having a weak surface tension in the vertical direction. Accordingly, the height of the mold resin that crawls up to the base of the lead terminal due to surface tension is lower than when the lead terminal is positioned at a location where the notched portion of the mold case is not provided. Therefore, when directly attaching to the substrate, the through hole of the lead terminal in the substrate is more reliably prevented from being sealed by the mold resin that has crawled up to the base of the lead terminal.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.
<First embodiment>
FIG. 1 is a plan view of a mold case used in a casting molding method as a method of manufacturing an LED lamp in the present embodiment. FIG. 2 is a perspective view thereof. The resin inlet at the upper end of the mold case 11 has a radius with a width of 1 mm or more and a depth of 0.3 mm or more at two locations in the vicinity where the lead terminals of the lead frame to be stored later are located and facing each other. A groove 12 penetrating in the direction is provided.
[0011]
When casting molding is performed using the mold case 11 having the above-described configuration, it is performed as follows. That is, epoxy resin is injected up to the bottom surface 12 a of the groove 12 in the mold case 11. In this case, as shown in FIG. 3, the epoxy resin 13 crawls up due to surface tension in the portion of the inner wall surface of the mold case 11 where there is no groove 12, and the surface tension in the vertical direction does not act on the portion where the groove 12 is present. It wo n’t crawl up. As a result, the shape of the liquid surface 13a of the epoxy resin 13 rises from the position of the bottom surface 12a of the groove 12 facing each other to the groove 12 and the groove 12 in the middle.
[0012]
In that state, by dipping a lead frame (not shown) on which the LED is mounted, as shown in FIG. 4, the epoxy resin 13 in the mold case 11 crawls up to the base of the lead terminal 14 due to surface tension, A raised portion 15 of resin is formed. As a result, as shown in FIG. 5, on the bottom surface of the epoxy resin 17 in the molded LED lamp 16, there is a raised portion 15 at the base of the lead terminal 14, a raised portion 18 at the outer peripheral portion, and both raised portions. A recess 19 between the portions 15 and 18 is formed. In addition, a portion without the raised portion 18 is formed at a position corresponding to the groove 12 on the outer peripheral edge of the bottom surface.
[0013]
As described above, according to the present embodiment, the groove 12 is provided in the resin inlet at the upper end of the mold case 11. Therefore, when casting mold is performed using the mold case 11, the raised portion 18 is formed on the outer peripheral edge of the bottom surface of the obtained LED lamp 16 in the portion where the groove 12 of the mold case 11 is not provided. A protrusion is configured. Further, since the lead terminal 14 is located in the vicinity of the groove 12 where the surface tension in the vertical direction is weak, the height of the epoxy resin 15 that crawls up to the base of the lead terminal 14 due to the surface tension is such that the lead terminal 14 is placed on the mold case 11. Compared to the case where the groove 12 is not provided, the height is lowered.
[0014]
In that case, the width of the groove 12 provided in the mold case 11 is 1 mm or more, and the depth is 0.3 mm or more. Therefore, the groove | channel 12 can exhibit the function of forming the part with the weak surface tension to a perpendicular direction on the inner wall face of the mold case 11 as mentioned above effectively.
[0015]
That is, when the LED lamp 16 formed according to the present embodiment is directly attached to the substrate, when the LED lamp 16 is pulled to the substrate side by the lead clinching force, the raised portion 18 at the outer peripheral edge of the bottom surface contacts the substrate surface. Therefore, the raised portion 15 at the base of the lead terminal 14 is prevented from completely closing the lead terminal through hole of the substrate. As a result, the air in the gap between the lead terminal through hole and the lead terminal 14 can be released to the outside through the recess 19 and the portion of the bottom outer peripheral edge that does not rise. That is, according to the present embodiment, the defective rate of soldering blow holes can be greatly reduced.
[0016]
Furthermore, in the case of a conventional mold case without the groove 12, it is difficult to control the amount of resin during casting. However, according to the mold case 11 of the present embodiment, when the resin amount becomes excessive, it can be discharged naturally from the groove 12 of the mold case 11, and the variation in the resin amount can be reduced.
[0017]
By the way, in the said embodiment, although the height of the liquid level of the epoxy resin inject | poured into the mold case 11 at the time of shaping | molding was demonstrated as the position of the bottom face 12a of the groove | channel 12, the height slightly lower than the position of the bottom face 12a. It does not matter. In short, it is sufficient that the height of the groove 12 is such that the surface tension in the vertical direction is weaker than other portions. When the amount of resin is reduced in a conventional grooveless mold case, the distance between the mold case and the frame terminal of the lead frame is narrow, so that the resin creeps up and does not decrease in height. In addition, since there is no groove in the mold case, the rising portion of the outer peripheral portion is formed around the entire bottom surface of the LED lamp. Therefore, when the substrate is directly attached, there is no air escape path in the outer peripheral portion of the bottom surface of the substrate and the epoxy resin, so that air is confined by pressing with the clinch. For this reason, blow holes are also generated.
[0018]
<Second Embodiment>
FIG. 6 is a plan view of a mold case used in the casting molding method as the LED lamp manufacturing method in the present embodiment. At the upper end portion of the mold case 21, rectangular cutout portions 23 having a predetermined length and a predetermined width are provided at four intervals on the inner peripheral wall 22 in the resin injection port. Using the mold case 21 configured as described above, the epoxy resin was injected to a height slightly beyond the position of the lower end surface 23a of the notch 23, and the lead terminal of the lead frame was positioned in the vicinity of the notch 23. The LED lamp is as shown in FIG.
[0019]
In this case, four protrusions 26 corresponding to the notches 23 of the mold case 21 are formed on the outer peripheral edge of the bottom surface of the epoxy resin 25 in the molded LED lamp 24 as shown in FIG. The cross section of the lower part of the epoxy resin passing through the two lead terminals 27 and 27 is as shown in FIG. In FIG. 8, a protruding portion 28 is formed by forming a raised portion 28 by the surface tension on the inner wall surface of the mold case 21 at the tip portions of the two protruding portions 26, 26 facing each other. Resin bulges 29 and 29 are formed at the bases of the two lead terminals 27 and 27 by surface tension.
[0020]
Further, the lead terminal 27 is positioned in the vicinity of the notch 23, and the epoxy resin is injected to a height slightly beyond the position of the lower end surface 23a of the notch 23. In that case, when the height of the surface of the epoxy resin beyond the lower end surface 23a of the notch 23 is low, the surface tension of the epoxy resin in the vertical direction at the notch 23 is low. Therefore, the height of the raised portion 29 of the resin at the base of the lead terminal 27 is lower than that when the lead terminal 27 is positioned at a portion where the notch 23 of the mold case 21 is not present.
[0021]
Therefore, when the LED lamp 24 is directly attached to the substrate, as shown in FIG. 8, when the LED lamp 24 is pulled to the substrate side by the lead clinching force, the raised portions 28 at the tips of the projections 26 and 26 are formed on the substrate. Because of the contact with the surface, the raised portion 29 at the base of the lead terminal 27 does not completely block the through hole 31 of the lead terminal 27 in the substrate 30. As a result, the air in the gap between the through hole 31 and the lead terminal 27 can be released to the outside. That is, according to the present embodiment, it is possible to prevent the formation of blow holes in the solder 32 and to greatly reduce the defect rate of soldering blow holes.
[0022]
In the above embodiment, the height of the liquid level of the epoxy resin injected into the mold case 21 at the time of molding has been described as being slightly higher than the position of the lower end surface 23a of the notch 23. The height may be slightly lower than the position of 23a or the position of the lower end surface 23a. In that case, the notch 23 functions exactly the same as the groove 12 in the first embodiment, and the height of the raised portion 29 at the base of the lead terminal 27 is reduced.
[0023]
As in each of the above embodiments, in the casting molding method, the groove 12 or the notch 23 is formed at the upper end of the mold case 11, 21, and the surface tension is applied to the outer periphery of the bottom surface of the molded LED lamps 16, 24. The protrusion part which consists of the rising parts 18 and 28 by is formed. Further, the lead terminals 14 and 27 are positioned in the vicinity of the groove 12 or the notch 23 at the time of molding so that the heights of the swelled portions 15 and 29 of the resin at the bases of the lead terminals 14 and 27 are reduced. Therefore, when the substrate is directly attached, the bulging portions 15 and 29 at the roots of the lead terminals 14 and 27 can be prevented from completely closing the lead terminal through holes of the substrate, and the formation of blow holes can be prevented. It is.
[0024]
<Third Embodiment>
FIG. 9 is a perspective view of an LED lamp 41 formed by a transfer molding method as a manufacturing method of the LED lamp in the present embodiment. The lower surface 42 a of the epoxy resin 42 in the LED lamp 41 is provided with a through groove 44 that passes through the projecting positions of the two lead terminals 43, 43 and extends in the arrangement direction of the lead terminals 43. The protrusions are formed on both sides. The through groove 44 is formed by deforming the shape of a lamp bottom mold (not shown).
[0025]
Thus, in this embodiment, the through groove 44 that passes through the protruding positions of the two lead terminals 43, 43 is provided on the lower surface 42 a of the LED lamp 41. Therefore, when the LED lamp 41 is directly attached to the substrate, even if the LED lamp 41 is pulled by the lead clinching force and pressed against the substrate, the gap between the through hole of the lead terminal 43 and the lead terminal 43 in the substrate is as follows. It is open to the outside through the through groove 44. Therefore, it is possible to ensure an air escape path between the through hole of the substrate and the lead terminal 43. That is, according to the present embodiment, when the LED lamp 41 formed by the transfer molding method is directly attached to the substrate, the defective rate of the soldering blowhole can be greatly reduced.
[0026]
In the present embodiment, a through groove 44 that passes through the protruding positions of the two lead terminals 43 and 43 is provided in the lower surface 42 a of the LED lamp 41. However, the present embodiment is not limited to this, and two grooves communicating individually from the roots of the two lead terminals 43 and 43 to the outer peripheral edge may be provided. In the present embodiment, the through groove 44 is formed by a transfer molding method, but may be formed by an injection molding method.
[0027]
<Fourth embodiment>
FIG. 10 is a perspective view of the LED lamp 51 formed by the injection molding method as the LED lamp manufacturing method in the present embodiment. On the lower surface 52a of the epoxy resin 52 in the LED lamp 51, V-shaped grooves 53, 53,... Arranged in one direction are provided. The V-shaped groove 53 is formed by deforming the shape of a lamp bottom mold (not shown).
[0028]
Thus, in the present embodiment, a plurality of V-shaped grooves 53, 53,... Are provided on the lower surface 52a of the LED lamp 51. Therefore, when the LED lamp 51 is directly attached to the substrate, even if the LED lamp 51 is pulled by the lead clinching force and pressed against the substrate, the gap between the through hole of the lead terminal 54 and the lead terminal 54 in the substrate is as follows. It is open to the outside through a V-shaped groove 53. Therefore, it is possible to secure an air escape path in the gap between the through hole of the substrate and the lead terminal 54. That is, according to the present embodiment, when the LED lamp 51 formed by the injection molding method is directly attached to the substrate, the defect rate of the soldering blowhole can be greatly reduced.
[0029]
In the present embodiment, V-shaped grooves 53 having a V-shaped cross section are arranged on the entire lower surface 52 a of the LED lamp 51. However, the present embodiment is not limited to this, and in short, it is only necessary to create an uneven structure on the lower surface 52a. Therefore, the cross-sectional shape of the concavo-convex structure may be other than the V-shaped cross section, and the concavo-convex structure may be formed only on a part of the lower surface 52a. In the present embodiment, the V-shaped groove 53 is formed by the injection molding method, but may be formed by the transfer molding method.
[0030]
【The invention's effect】
As apparent from the above, the production method of L ED lamp of the present invention, a lead frame LED is mounted with formed by resin molding, an LED lamp provided with a protrusion on the bottom surface of the mold resin, casting molding method Injecting mold resin to a height near the lower end of the notch provided on the inner wall of the resin inlet of the mold case, and positioning the lead terminal in the vicinity of the notch In the molded resin, the lead frame is immersed in the outer peripheral edge of the bottom surface of the molded resin in the molded LED lamp due to the difference in vertical surface tension acting on the mold resin on the inner wall surface of the mold case. A portion having a raised portion and a portion having no raised portion of the resin can be formed.
[0031]
Further, since the lead terminal is positioned in the vicinity of the notch provided in the mold case, the height of the mold resin that rises up to the root of the lead terminal due to surface tension is positioned at a place where the notch is not present. Can be lower than if Therefore, when the mold resin is pulled by the lead clinching force when directly attaching to the substrate, it is possible to reliably prevent the through hole of the lead terminal in the substrate from being completely blocked.
[Brief description of the drawings]
FIG. 1 is a plan view of a mold case used in a casting molding method as an LED lamp manufacturing method according to the present invention.
FIG. 2 is a perspective view of the mold case shown in FIG.
FIG. 3 is a side view showing a liquid surface shape of an epoxy resin in the mold case shown in FIG. 1;
4 is a side view showing a state in which a lead frame is immersed in the mold case shown in FIG. 3; FIG.
FIG. 5 is a side view of an LED lamp molded using the mold case shown in FIG. 1;
6 is a plan view of a mold case different from FIG. 1. FIG.
7 is a perspective view of an LED lamp molded using the mold case shown in FIG. 6. FIG.
FIG. 8 is a side view showing a state where the LED lamp shown in FIG. 7 is directly attached to a substrate.
FIG. 9 is a perspective view of an LED lamp molded by a transfer molding method as a manufacturing method of the LED lamp of the present invention.
FIG. 10 is a perspective view of an LED lamp molded by an injection molding method as an LED lamp manufacturing method of the present invention.
FIG. 11 is a side view of an LED lamp molded by a conventional casting molding method.
12 is a view showing a state where the LED lamp shown in FIG. 11 is directly attached to a substrate.
[Explanation of symbols]
11, 21 ... Mold case,
12 ... groove,
13, 17, 25, 42, 52 ... epoxy resin,
14, 27, 43, 54 ... lead terminals,
15, 29 ... Swelling part of the lead terminal,
18, 28 ... the raised part of the outer peripheral edge of the bottom surface,
16, 24, 41, 51 ... LED lamps,
19 ...
22 ... Inner wall,
23 ... notch,
26 ... protrusions,
30 ... substrate,
31 ... through hole,
32 ... Solder,
44 ... through groove,
53 ... V-shaped groove.

Claims (1)

A method of manufacturing a light-emitting diode lamp , which is formed by resin molding a lead frame on which a light-emitting diode is mounted, and forming a light- emitting diode lamp having a protrusion on the bottom surface of the mold resin by a casting molding method ,
Using a mold case provided with notches at least at two locations facing each other on the inner wall of the resin injection port,
Injecting mold resin to a height near the lower end of the notch in the mold case,
A method of manufacturing a light-emitting diode lamp , wherein a lead terminal is positioned in the vicinity of a notch portion of the mold case, and the lead frame is immersed in a mold resin in the mold case .

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