JPS609663B2 - Method for forming the exterior part of a light emitting diode - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming an exterior part when manufacturing a light emitting diode by packaging a light emitting element with an insulating material.

Conventionally, for light emitting diodes, a light emitting element and a thermosetting epoxy liquid resin were stored in a container, and after the resin was heated and cured, the product was removed from the container. Such a process requiring heat curing treatment has the following drawbacks. [al
Curing of epoxy-based liquid resin requires a long time at room temperature or heating until it is completely cured, resulting in low productivity.
After heating at 12030 for 1.5 hours, further heat at 100qC.
16 hours of heating is required.

{b- Long-term heating during heat curing deteriorates the performance of the light emitting element.

'c' Long-term heating during heat curing causes loss of optical selectivity of the resin container and shortens the life of the container.

'd} Due to the long-term heating during heat curing, the epoxy liquid resin that is the exterior material is burned, making it difficult to finish in vivid colors (red, green, etc.) or transparency. Furthermore, the color tone is not constant due to variations in temperature. [e} The heat during heating and curing causes a difference in the coefficient of linear expansion between the resin material and the metal material, leading to breakage of the lead wire and poor walking performance.

'f) Epoxy materials are generally two-component types that require measuring and mixing, and have a short pot life.

In the present invention, a transparent container is filled with a liquid exterior material that is cured by ultraviolet rays, and the liquid exterior material is cured in a short time by irradiation with UV rays alone or in combination with UV irradiation and short-term heating. The purpose of this invention is to manufacture high-quality light-emitting diodes with extremely high productivity by forming the exterior portion of the light-emitting diode using the same method.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the structure of a COM type light emitting diode.
1 represents a comb, 2 represents a light emitting element, 3 represents an exterior material, and 4 represents a lead wire.

FIG. 2 shows a part of the diode group and comb group separated from the container after a large number of light emitting elements have been cured with resin in the container.

Figure 3 shows the exterior material 3 exposed to ultraviolet light in an ultraviolet irradiation furnace.
The structure of the process of curing is shown.

Here, 5 is a container with high ultraviolet transmittance, 6 is an ultraviolet irradiation lamp, and 7 is a metal plate for fixing the container 5. In the manufacturing method of the present invention, first, a liquid exterior material 3 is injected into a transparent container 5 set on a fixing plate 7, and then a commu with a light emitting element 2 bonded to it and a lead wire connected is inserted into a stereotaxic device. do.

Thereafter, the liquid exterior material is cured by passing through an ultraviolet irradiation oven. At this time, ultraviolet rays are first irradiated from a part other than the closed part of the transparent container having the closed part on the upper surface, for example, from the lower part. By using this irradiation method,
Distortion due to curing shrinkage of the liquid exterior material 3 can be absorbed by the opening side, that is, the end face on the comb 1 side, and a faithful product of the container 5 with less "distortion" can be produced. If the liquid exterior material is cured by irradiating ultraviolet rays from the upper surface, which is the entrance part, the problem may occur that the shape of the exterior part is "distorted" due to rapid curing shrinkage. After curing the liquid exterior material by irradiating it with ultraviolet rays, it is separated from the container to obtain the product. The exterior material used in the present invention is a material that is reactively cured by ultraviolet irradiation, and is a compound having an acryloyl group or a methacryloyl group.

For example, acrylic acid or methacrylic acid; alkyl, cycloalkyl, glycidyl, tetrahydrofurfuryl,
Examples include acrylates such as allyl and hydroxyalkyl; mono- or poly(meth)acrylates such as alkylene glycol, polyoxyalkylene glycol, trimethylolpropylene, bentaerythritol, and the like. Further examples include epoxy (meth)acrylate resin, oligoestel (meth)acrylate, urethane (meth)acrylate resin, and the like. Here, (meth)acrylate represents either acrylate or methacrylate, or both. Next, photopolymerization catalysts such as benzoine, benzoine alkyl ether, Q-substituted penzoin, anthraquinone, alkyl-substituted anthraquinone, benzyl, and benzophenone are used as curing catalysts for these resins.

As a starting point, organic peroxides such as penzoyl peroxide, methyl ethyl ketone peroxide, t-butyl hydroperoxide, cumene hydro'g oxide, dicumyl/g oxide, t-butyl peroxybenzoate, etc. or azobis Examples include azo compounds such as isoptilonitrile. Appropriate materials are selected from these exterior materials and curing catalysts according to each use of the light emitting diode.

For example, when making a transparent exterior material, select an exterior material and a curing catalyst with excellent transparency. When forming a transparent exterior part, it is sufficient to use only a photopolymerization initiator as a curing catalyst since the exterior material can be cured only with ultraviolet rays.
When forming a colored exterior part, it is necessary to blend pigments, dyes, fillers, etc. into the exterior material.

In this case, the exterior material often becomes non-transparent to ultraviolet rays, and therefore sufficient curing cannot be achieved with the photopolymerization initiator alone. Therefore, a photopolymerization initiator and a thermal polymerization initiator are used in combination, and the material is cured by a combination of ultraviolet irradiation and heating. In addition, the container that determines the shape of the exterior part is made of materials that are highly transparent to ultraviolet rays and electron beams, such as acrylic resin, vinyl chloride resin, and methylbentene polymer (TPX).
) is used. Next, the present invention will be specifically explained with reference to Examples.

Example 1 Here, an exterior material with the following composition was used.

Weight% of bisphenol A type epoxy acrylate 6 Weight% of ethylene glycol dimethacrylate 2 Methyl methacrylate 1% by weight Photopolymerization initiator 1% by weight thermal polymerization initiator
A curable resin composition (exterior material) having the above composition of 1% by weight is filled into a transparent container 5 made of TPX material, and the light emitting element 2 is inserted into the orientation calendar inside the exterior material 3. 5 was attached to the metal plate 7 shown in FIG.

A high-pressure mercury lamp 6 of 80 W/skin was used to irradiate ultraviolet rays 4 from the bottom and side surfaces of the container to harden the liquid exterior material.

In this case, curing may be carried out using only a photopolymerization initiator, but by using a thermal polymerization initiator in combination, it acts as an accelerator for the photopolymerization initiator, and the curing reaction can be completed in a short time. If the exterior material 3 is transparent, it can be sufficiently cured by UV irradiation alone, but if the exterior material contains a pigment, dye, or filler as a coloring substance depending on the application of the light emitting diode, It is cured using a combination of ultraviolet light and heat. Note that the ultraviolet light generation source 6 used for ultraviolet irradiation is a normal ultra-high pressure mercury lamp, high pressure mercury lamp, low pressure mercury lamp, metal halide lamp, xenon lamp, chemical lamp, or the like. Further, as a heating source, a hot air nichrome heater wire, an infrared lamp, a far infrared heater, etc. are used. Example 2 Here, an exterior material having the following composition was used.

Bisphenol A type epoxy acrylate 6% by weight Polyester acrylate 4% by weight Pigment
0.5% by weight of these components were uniformly mixed to prepare a curable resin composition.

This resin composition was used in the same manner as in Example 1.

After setting on the metal plate 5, the resin composition was instantly cured using an electron beam accelerator with an output of 500 KV. As is clear from the above explanation, the present invention has many effects shown below. Productivity is high because the exterior material can be cured in a short time, from several seconds to several minutes, by irradiation with ultraviolet rays or electron beams.

'b} By curing the exterior material at a low temperature for a short time, there is no deterioration in the performance of the light emitting element, and the life of the resin mold is also long.

[c} Because the exterior material can be cured at low temperatures in a short period of time, there is no discoloration during curing, resulting in products with stable color tone.

Skin Since the exterior material can be cured at low temperatures, there is no disconnection due to differences in linear expansion coefficients, resulting in a high yield.

{e} As it is a one-component type, there is no need for measuring or mixing, and it has a long pot life, making it easy to work with.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a light emitting diode, Fig. 2 is a partial cross-sectional view showing a number of light emitting diodes connected to a comb, and Fig. 3 is a block diagram schematically showing the apparatus used in this method invention. . 1... Comb, 2... Light emitting element, 3... Exterior material, 4
...Lead wire, 5...Container, 6...
...Ultraviolet irradiation lamp, 7...Metal plate for fixing the container. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. When manufacturing a light-emitting diode that includes at least a light-emitting element and an exterior material that covers the light-emitting element, the liquid exterior material is filled into a container made of a material that is highly transparent to ultraviolet rays or electron beams, and then the light emitting device is emitted. The diode is embedded in the exterior material, and the liquid exterior material is then cured by UV irradiation, electron beam irradiation, or a combination of both and heating, starting from the bottom farthest from the opening of the container. Characteristic method for forming the exterior part of a light emitting diode.