JP2003031849A - Light emitting diode and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an LED which can be increased in size as large as a lead frame type LED, while retaining its surface-mounting advantage of effectively using its rear surface when it is mounted on a printed board. SOLUTION: A light emitting diode 50 is equipped with a board 1 provided with a main surface, a light emitting diode chip 3 arranged on the above main surface of the board 1, and a resin unit covering the light emitting diode chip 3. The resin unit is composed of a first part forming a lens 4 on the main surface and a second part coming into contact with the rear of the board 1, and the first part and the second part are jointed together in one piece so as to pinch the board 1 between them.

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 used for an outdoor display panel and the like and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, light emitting diodes (hereinafter referred to as "LEDs") have been widely used for display boards and the like. The LEDs are roughly classified into a surface mount type and a lead frame type.

As an example of the surface mount type LED, L
A plan view of the ED 150 is shown in FIG.
FIG. 11 shows a sectional view taken along the line I of FIG. LED150
Are covered with electrode terminals 113a and 113b so as to cover a part of the surface of the resin substrate 101 and face each other, and a light emitting diode chip (hereinafter referred to as "LED chip") is provided on one end of one electrode terminal 113b. 3) is arranged. The end of the other electrode terminal 113a and the LED chip 3 are connected by a wire 9 made of copper or the like. LED chip 3, whole wire 9 and electrode terminal 1
A resin lens 104 is formed so as to cover a part of 13a and 113b. FIG. 12 shows a surface-mounted LED mounted on a printed circuit board 130. The LED 150 is mounted using cream solder or an adhesive, and the wiring 131 formed on the surface of the printed board 130 and the electrode terminals 113a and 113b.
And are electrically connected. Surface mount type LE
Examples of D are JP-A-6-5926 and JP-A-9-36.
It is also disclosed in Japanese Patent No. 432.

FIG. 13 shows a sectional view of an LED 250 as an example of a lead frame type LED. LED25
In No. 0, several electrode terminals 213 are fixed in the lens-shaped lens 204, and the LED chip 3 is fixed on one of the electrode terminals 213. There is. The electrode terminals 213 and the LED chips 3 are connected by wires 9 made of copper or the like. FIG. 14 shows a case where such a lead frame type LED is mounted on a printed circuit board. An example of a lead frame type LED is disclosed in Patent No. 29.
It is also disclosed in Japanese Patent Application Laid-Open No. Hei 10-4216.

[0005]

Generally, lead frame type LEDs are often used for road display boards and outdoor advertising lights. This is because, in the lead frame type, a silver-plated reflection cup is easily attached due to its shape, so that it is easy to increase the luminous intensity. Further, outdoors, a large lamp having a large volume of transparent resin portion is desired in order to protect the LED chip and enhance reliability. Further, in order to reach the light at a long distance, it is necessary to collect the light, and for that purpose, a large lamp is necessary. On the other hand, the lead frame type is easy to manufacture a large lamp. This is also the reason why lead frame type LEDs are often used for road display boards and outdoor advertising lights.

However, in the lead frame type, since the electrode terminals 213 extend like feet, when mounting on the printed circuit board, a hole is formed in the printed circuit board 130 as shown in FIG. After inserting the electrode terminal 213, the substrate surface opposite to the LED body is soldered by a solder dipping device. Since it is necessary to form a hole in the substrate as described above, and the back surface of the portion where the LEDs are arranged cannot be used for other purposes, the wiring pattern is limited and it is not suitable for miniaturization.
Further, as shown in FIG. 15, the position of the optical axis is easily displaced,
It was difficult to keep the optical axis constant.

On the other hand, in the surface mounting type LED as shown in FIGS. 10 and 11, it is not necessary to make a hole in the substrate for mounting, and therefore the back surface of the substrate can be freely used. Therefore, it is advantageous for miniaturization, and has been mainly used for small mobile devices such as mobile phones and MDs (Mini Disc (registered trademark)). However, in this case, since the transparent resin lens 104 is directly mounted on the substrate 101 as shown in FIG.
When the size is increased, the size of the transparent resin cannot be increased due to the problem that the transparent resin peels off due to the difference in expansion coefficient between the transparent resin and the substrate 101 during reflow soldering. Also,
The surface mount type LED often uses a resin insulating substrate as the substrate 101 and has a large thermal resistance, and thus has a drawback that a large current cannot flow.

Therefore, the present invention provides an LED and a manufacturing method thereof which can be increased in size like a lead frame type while maintaining the advantage of the surface mounting type that the back surface can be effectively used when mounting on a printed circuit board. The purpose is to

[0009]

To achieve the above object, a light emitting diode according to the present invention comprises a substrate having a main surface, a light emitting diode chip disposed on the main surface side of the substrate, and the light emitting diode. A resin portion covering the chip, the resin portion including a first portion forming a lens on the main surface and a second portion in contact with the back side of the substrate, and the first portion and the The substrate is sandwiched while being integrally connected to the second portion. By adopting this configuration, the resin part is
Since the substrate is sandwiched from both sides by the portion and, even if there is some difference in expansion coefficient between the substrate and the resin, the resin portion can be prevented from peeling off. Therefore, the reliability of the LED can be increased, and the LED
The overall size can be increased.

In the above invention, preferably, a heat dissipation layer is formed on a back surface which is a surface opposite to the main surface of the substrate, and the heat dissipation layer has a mounting area exposed to the main surface side. Including, the light emitting diode chip is mounted in the mounting area. By adopting this configuration, the light emitting diode chip is mounted in the mounting area, and the mounting area is a part of the heat dissipation layer. Therefore, the heat generated from the light emitting diode chip must be quickly dissipated. You can

In the above invention, preferably, the heat dissipation layer is a plate material made of a copper alloy. By adopting this structure, since the copper alloy has good thermal conductivity, it is possible to efficiently dissipate heat.

In the above invention, preferably, a plurality of the light emitting diode chips are mounted in one mounting area. By adopting this configuration, LE
It is possible to color D. Further, by mounting a plurality of light emitting diode chips in one mounting region, they can be arranged close to each other, and color mixing can be improved.

In the above invention, preferably, the heat dissipation layer includes a runner portion which is a groove-shaped portion in which a part of the back surface of the substrate is exposed by opening in a linear shape.
The portion of includes a portion that has entered the inside of the runner portion. By adopting this configuration, even if most of the back surface of the substrate is used as a heat dissipation layer, it is possible to secure the resin portion that sandwiches the substrate due to the presence of the runner portion, and because the runner portion is linear, It is easy to cast and mold, and the back surface can be made flat with the heat dissipation layer.

In order to achieve the above object, a method of manufacturing a light emitting diode according to the present invention includes a substrate having a main surface, a light emitting diode chip arranged on the main surface side of the substrate, and the light emitting diode chip. A heat dissipation layer is formed on a back surface which is a surface opposite to the main surface of the substrate, and a resin portion for covering the back surface of the substrate. A board with a heat dissipation layer provided with a plate-like heat dissipation layer having an opening is manufactured,
The step of manufacturing a substrate with a heat dissipation layer and the groove-shaped runner portion formed by exposing the part of the substrate by the opening are substantially closed by a first die having a flat surface portion. A resin part forming step of forming the resin part by injecting a resin into the runner part. By adopting this method, the groove-shaped runner portion can be filled with resin so as to be flush with the heat dissipation layer. Therefore,
An LED having a flat back surface can be easily manufactured.

In the above invention, preferably, in the resin portion molding step, the first mold has a concave portion in contact with the back surface of the substrate with the heat dissipation layer and having a shape corresponding to a lens covering the light emitting diode chip. The resin is injected while the second mold is in contact with the main surface. By adopting this method, the lens can be molded at the same time, and the portion pressing the back surface of the substrate and the lens can be made of the same material.

In the above invention, preferably, in the resin portion molding step, a step of boring a through hole is previously formed in the substrate with the heat dissipation layer so that the runner portion and the recess are communicated with each other. By adopting this method, the runner portion and the concave portion can be communicated with each other through the through hole, and the resin portion that wraps around both sides of the substrate through the through hole will sandwich both sides of the substrate. The adhesion between the substrate and the substrate is improved.

In the above invention, preferably, in the drilling step, an injection hole and a discharge hole are drilled as the through holes, and in the resin portion molding step, the resin is passed from the runner portion through the injection hole. Enter the above recess,
Flow from the concave portion through the discharge hole to enter the runner portion. By adopting this method, the flow of resin can be regulated in a fixed direction, and the runner portion and the recess can be surely filled with resin.

In the above invention, preferably, in the step of manufacturing the substrate with the heat dissipation layer, the substrate with the heat dissipation layer is
It has a longitudinal shape in which unit plate-shaped portions to be included in one light emitting diode are arranged in a line and connected to each other, and in each of the unit plate-shaped portions, the runner portion has a width substantially perpendicular to the longitudinal direction of the longitudinal shape. It is manufactured as a pre-divided substrate provided along the direction, and in the resin part molding step, resin is independently poured into each of the runner parts. By adopting this method, the heat shrinkage of the resin mainly acts in the width direction of the substrate with the heat dissipation layer, and the warp of the substrate with the heat dissipation layer in the longitudinal direction can be suppressed.

In the above invention, preferably, a plate material made of a copper alloy is used as the heat dissipation layer. By adopting this method, a heat dissipation layer having good thermal conductivity can be obtained.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION (Embodiment 1) (Structure) Referring to FIGS. 1 to 6, an LED according to Embodiment 1 of the present invention will be described. This LED5
As shown in FIG. 1, 0 has a structure in which a bullet-shaped lens 4 similar to the bullet-shaped lens included in the conventional lead frame type LED is formed on the upper surface of the substrate 1. The lens 4 is formed of a transparent resin so as to cover the LED chip 3 and the wires 9 together. The transparent resin forming the lens 4 also wraps around the lower side of the substrate 1 through the through holes 7a and 7b and fills the runner portions 11a and 11b. A copper alloy layer 2 is provided on the lower surface of the substrate 1 as a heat dissipation layer.

A top view of the LED 50 is shown in FIG. 2 assuming that the lens 4 is completely transparent and the problem of refractive index can be ignored. When the substrate 1 is viewed from above, there is an opening in the center and a part of the copper alloy layer 2 is exposed, and the mounting area 1
It is 5. The LED chip 3 is mounted in the mounting area 15 and is electrically connected to the wiring pattern 12 stretched on the upper surface of the substrate 1 by the wire 9. The substrate 1 has a substantially square shape, and electrode terminals 13 are formed at the four corners. A wiring pattern 12 is laid from the electrode terminals 13 at the four corners so as to crawl on the upper surface of the substrate 1. One of them is connected to the base of the mounting area 15, and the other three are the mounting area. Wires 9 are respectively connected to the three LED chips 3 arranged in 15. Although the number of the LED chips 3 is three in this example, it may be one. Further, the number may be two or four or more, if necessary. By mounting a plurality of LED chips 3, it is possible to colorize the LEDs.

A sectional view taken along the line III-III in FIG. 2 is shown in FIG. 3, and a sectional view taken along the line IV-IV is shown in FIG. It can be seen that a part of the copper alloy layer 2 stretched on the back surface of the substrate 1 is the base of the mounting region 15. That is, one of the wiring patterns 12 connected to the base of the mounting region 15 brings the entire copper alloy layer 2 to the same potential. Further, on the lower side of the substrate 1, a resist film 16 covers the surface of the copper alloy layer 2.

According to FIG. 4, the transparent resin forming the lens 5 is the runner portions 11a, 11 on the lower side of the substrate 1 as they are.
It can be seen more clearly that the substrate 1 is sandwiched between the substrates 1 and b.

FIG. 5 shows the LED 50 as viewed from below. Further, FIG. 6 shows a state where only the arrangement of the copper alloy layer 2 is extracted on the surface visible in FIG. Copper alloy layer 2
Are divided into four corresponding to the electrode terminals 13 at the four corners. As shown in FIG. 5, only portions of the copper alloy layer 2 necessary for the electrode terminals 13 are exposed and the other portions are covered with a resist film 16.

(Operation / Effect) In the above-mentioned LED, since the transparent resin portion also wraps around the back side of the substrate 1 through the through holes 7a and 7b to sandwich the substrate from both sides, even if it is transparent to the substrate 1. Even if there is a slight difference in coefficient of expansion with the resin, it is possible to prevent the transparent resin portion from peeling off as in the conventional surface mount type LED. Therefore, the size of the entire LED can be increased. Since the size can be increased, it is possible to increase the axial luminous intensity. Also, for the heat generated from the LED chip 3,
Since the copper alloy layer 2 is stretched on the back surface of the substrate 1 and the LED chip 3 is directly grounded to a part of the copper alloy layer 2, heat dissipation can be sufficiently performed. In addition, since peeling is less likely to occur between the transparent resin portion and the substrate, the LED can have high reliability.

Further, unlike the conventional lead frame type, the electrode terminals do not project to the back surface and the back surface is flat, so that it can be mounted as it is on a printed circuit board, etc. Since it can be effectively used for applications, it can contribute to high integration of the entire printed circuit board. In addition, since it can be mounted by using a flat electrode, it is possible to prevent optical axis deviation.

(Second Embodiment) (Manufacturing Method) With reference to FIGS. 5 to 9, an LED manufacturing method according to a second embodiment of the present invention will be described. First, as a material of the substrate 1, a substrate made of an insulating material such as glass epoxy resin and having a copper foil stretched on one surface is prepared. For example, a copper foil having a thickness of 17 μm can be used. This copper foil will later become the wiring pattern 12. 25 on the side without the copper foil
A copper alloy plate having a thickness of about 0 to 350 μm is attached with an adhesive. This surface is the lower surface in FIGS. 3 and 4, and is hereinafter referred to as “back surface”. This copper alloy plate will later become the copper alloy layer 2.

Next, holes for forming the through holes 7a and 7b and holes to be circular arcs at the four corners of FIG. 5 are drilled. Copper plating is applied to the holes, and the copper parts on both sides are electrically connected. A resist film is formed on both front and back surfaces and copper is etched. On the surface on which the copper foil is stretched, the wiring pattern 12 is formed by this etching. On the back surface, grooves are formed by this etching, and individual L
The copper alloy layer 2 corresponding to ED has a pattern as shown in FIG. Runner portions 11a and 11b which are portions without the copper alloy layer 2 are formed so as to be connected to the through holes 7a and 7b. As a whole, the substrate 20 with a heat dissipation layer is formed as shown in FIG. In FIG. 7, the through holes 7a,
Only 7b and runners 11a and 11b are shown, and others are omitted. The part of the circle indicated by the two-dot chain line is the individual L
This is the position where the lens 4 of the ED is arranged. However,
Since the back surface is visible, the lens 4 is formed on the opposite surface. The substrate 20 with the heat dissipation layer has a strip shape in which the portions to be the individual LEDs are arranged in a row and connected, and the runner portions 11a and 11b are provided in parallel to the short sides thereof.

Further, nickel and gold are plated on the exposed copper portions on both the front and back surfaces. After that, as shown in FIG. 5, a predetermined portion of the back surface is covered with the resist film 16. LEDs on the mounting area 5 of the substrate 20 with the heat dissipation layer
Attach chip 3. This attachment can be done by die bonding with silver paste. Next, the LED chip 3 and the predetermined position of the wiring pattern 12 are connected by the wire 9.

This heat-dissipating layer-equipped substrate 20 is fitted into the recess of the lower mold 22 as shown in the plan view of FIG. 8 (b), and the upper mold 21 as shown in the sectional view of FIG. 8 (a). Cover from above. Grooves are formed in the upper mold 21 as main runners 24a and 24b, and a groove as a sub-runner 25 is formed so as to branch from the main runner 24a. The sub-runner 25 is arranged so as to be connected to the runner portion 11 a of the substrate 20 with the heat dissipation layer via the groove provided in the lower mold 22. On the other hand, a groove as an air vent 26 is formed in the lower mold 22 so as to be connected to each of the main runners 24b, and the air vent 26 is arranged so as to be connected to the runner portion 11b. Figure 8 (a)
As shown in, the lower mold 22 is provided with a recess 23 corresponding to the shape of the lens 4. Directly above the substrate 20 with the heat dissipation layer, the surface of the upper mold 21 is flat.

As a result, as shown by the arrow in FIG. 8 (b), if the melted resin is poured from the main runner 24a, it flows through the sub-runner 25 into the runner portion 11a, and as shown in FIG. 8 (a). The recess 2 of the lower mold 22 as shown by the arrow
3 and can flow to the air vent 26. The air pushed out of these spaces by the inflow of the resin can pass through the air vent 26 and escape to the main runner 24b. The cross section of the substrate 20 with the heat dissipation layer is enlarged to show the resin flow in FIG. Runner section 11
The resin from a enters the recess 23 through the through hole 7a, and further through the through hole 7b.
You can escape to. Pour the resin in this way,
The lens 4 is formed by molding, and at the same time, the resin portion that fills the runner portions 11a and 11b is also formed so as to be connected to the lens 4. A transparent epoxy resin can be used as the resin. Next, the substrate 20 with the heat dissipation layer is cut by a dicing machine and divided into individual LEDs. Thus, the LED (see FIGS.
(See FIG. 4) is obtained.

(Operation / Effect) According to the above manufacturing method,
A highly reliable LED that prevents peeling of the transparent resin part,
Can be mass-produced efficiently. In addition, it is possible to cope with an increase in size of the LED. Furthermore, since the flat surface of the upper mold 21 defines the back surface of the LED, it is possible to obtain an LED having a high back surface flatness.

At the time of resin molding, a resin flow path is formed separately for each individual LED, and since the resin flow path is provided perpendicularly to the longitudinal direction of the substrate 20 with the heat dissipation layer, The heat shrinkage of the resin mainly acts in the direction parallel to the short side of the substrate 20 with the heat dissipation layer, and the warp of the substrate 20 with the heat dissipation layer in the longitudinal direction can be suppressed.

The above-described embodiment disclosed this time is illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description but by the scope of the claims, and includes meaning equivalent to the scope of the claims and all modifications within the scope.

[0035]

According to the present invention, since the resin portion sandwiches the substrate from both sides by the first portion forming the lens on the main surface of the substrate and the second portion contacting the back side of the substrate, Even if there is a slight difference in expansion coefficient between the substrate and the resin, the resin portion can be prevented from peeling off. Therefore, the reliability of the LED can be improved and the LE
It is possible to increase the size of D. Further, since the light emitting diode chip is directly mounted on the mounting area, which is a part where the heat dissipation layer is partially exposed, the heat generated from the light emitting diode chip can be quickly dissipated.

[Brief description of drawings]

FIG. 1 is a front view of a light emitting diode according to a first embodiment of the present invention.

FIG. 2 is a plan view of the light emitting diode according to the first embodiment of the present invention.

FIG. 3 is a sectional view taken along the line III-III in FIG.

4 is a cross-sectional view taken along the line IV-IV in FIG.

FIG. 5 is a rear view of the light emitting diode according to the first embodiment of the present invention.

FIG. 6 is a plan view showing only the arrangement of copper alloy layers of the light emitting diode according to the first embodiment of the present invention.

FIG. 7 is a plan view of a substrate with a heat dissipation layer used in a method for manufacturing a light emitting diode according to a second embodiment of the present invention.

8A and 8B are explanatory views showing a state in which upper and lower molds are combined in a method for manufacturing a light emitting diode according to a second embodiment of the present invention. In addition, (a) is a cross-sectional view and (b) is a plan view of a state where a substrate with a heat dissipation layer is installed in a lower mold.

FIG. 9 is an explanatory diagram showing a resin flow path in a portion to be an LED in the method for manufacturing a light-emitting diode according to the second embodiment of the present invention.

FIG. 10 is a plan view of a surface mount type light emitting diode according to the prior art.

11 is a cross-sectional view taken along line XI-XI in FIG.

FIG. 12 is a cross-sectional view showing a mounted state of a surface mount type light emitting diode based on a conventional technique.

FIG. 13 is a cross-sectional view of a lead frame type light emitting diode according to the related art.

FIG. 14 is a sectional view showing a state in which a lead frame type light emitting diode based on a conventional technique is mounted.

FIG. 15 is an explanatory diagram of a problem of a lead frame type light emitting diode based on a conventional technique.

[Explanation of symbols]

1,101 substrate, 2 copper alloy layer, 3 LED chip,
4,104,204 lens, 7a, 7b through hole, 9 wire, 11a, 11b runner part, 12
Wiring pattern, 13, 113a, 113b, 213 Electrode terminal, 15 mounting area, 16 resist film, 20 substrate with heat dissipation layer, 21 upper mold, 22 lower mold, 23 recess, 24a, 24b main runner, 25 sub runner ,
26 air vents, 50, 150, 250 LEDs, 1
30 printed circuit boards, 131 wiring.

Claims (11)

[Claims] 1. A substrate having a main surface, a light emitting diode chip arranged on the main surface side of the substrate, and a resin portion covering the light emitting diode chip, wherein the resin portion is provided on the main surface. Including a first portion forming a lens and a second portion in contact with the back side of the substrate,
The light-emitting diode, wherein the first portion and the second portion sandwich the substrate while being integrally connected. 2. A heat dissipation layer is formed on a back surface which is a surface opposite to the main surface of the substrate, and the heat dissipation layer includes a mounting region exposed to the main surface side, and the light emitting layer is provided. The light emitting diode according to claim 1, wherein a diode chip is mounted on the mounting area. 3. The light emitting diode according to claim 2, wherein the heat dissipation layer is a plate material made of a copper alloy. 4. A plurality of the light emitting diode chips,
The light emitting diode according to claim 2, which is mounted in one of the mounting areas. 5. The heat dissipation layer includes a runner portion which is a groove-like portion in which a part of the back surface of the substrate is exposed by opening in a linear shape, and the second portion includes a runner portion of the runner portion. The light emitting diode according to any one of claims 2 to 4, which includes a portion that penetrates inside. 6. A substrate having a main surface, a light emitting diode chip arranged on the main surface side of the substrate, and a resin portion covering the light emitting diode chip, the substrate being on the opposite side of the main surface of the substrate. A method for manufacturing a light emitting diode, wherein a heat dissipation layer is formed on a back surface, which is a surface, wherein a board with a heat dissipation layer is provided on the back surface of the substrate, wherein a plate-like heat dissipation layer having a linear opening is provided. And a step of manufacturing a substrate with a heat dissipation layer, and a state in which a groove-shaped runner portion formed by exposing a part of the substrate by the opening is substantially closed by a first die having a planar portion. And a step of forming a resin portion by injecting a resin into the runner portion to form a resin portion. 7. In the resin part molding step, the second mold is in contact with the back surface of the substrate with the heat dissipation layer, and has a second metal mold having a concave portion having a shape corresponding to a lens covering the light emitting diode chip. The method for manufacturing a light-emitting diode according to claim 6, wherein the resin is injected while a mold is in contact with the main surface. 8. The method of manufacturing a light emitting diode according to claim 7, further comprising a step of boring a through hole in the substrate with the heat dissipation layer in advance so that the runner portion and the recess are communicated with each other in the resin portion molding step. Method. 9. In the drilling step, an injection hole and a discharge hole are drilled as the through holes, and in the resin part molding step, the resin enters the recess from the runner part through the injection hole. 9. The method for manufacturing a light emitting diode according to claim 8, wherein the light is supplied from the recess through the discharge hole to enter the runner portion. 10. In the step of manufacturing a substrate with a heat dissipation layer, the substrate with a heat dissipation layer has a longitudinal shape in which unit plate-shaped portions to be included in one light emitting diode are arranged in a line and connected to each other. In each of the unit plate-shaped portions, the runner portion is manufactured as a pre-division substrate provided along a width direction that is substantially perpendicular to the longitudinal direction of the longitudinal shape, and in the resin portion molding step, each of the runner portions is individually formed. The method for manufacturing a light-emitting diode according to claim 6, wherein the resin is poured independently. 11. The method of manufacturing a light emitting diode according to claim 6, wherein a plate material made of a copper alloy is used as the heat dissipation layer.