WO2008097055A1 - Encapsulation method of light emitting diode - Google Patents

Encapsulation method of light emitting diode Download PDF

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Publication number
WO2008097055A1
WO2008097055A1 PCT/KR2008/000775 KR2008000775W WO2008097055A1 WO 2008097055 A1 WO2008097055 A1 WO 2008097055A1 KR 2008000775 W KR2008000775 W KR 2008000775W WO 2008097055 A1 WO2008097055 A1 WO 2008097055A1
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WO
WIPO (PCT)
Prior art keywords
encapsulating
manufacturing
led lamp
lamp according
hydroxy
Prior art date
Application number
PCT/KR2008/000775
Other languages
French (fr)
Inventor
Yong Hoon Cho
Hao Wang
Original Assignee
Chungbuk National University Industry-Academic Cooperation Foundation
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Filing date
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Publication of WO2008097055A1 publication Critical patent/WO2008097055A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C41/00—Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor
    • B29C41/02—Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor for making articles of definite length, i.e. discrete articles
    • B29C41/14—Dipping a core
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C41/00—Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor
    • B29C41/003—Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor characterised by the choice of material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2011/00—Optical elements, e.g. lenses, prisms
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/4805—Shape
    • H01L2224/4809—Loop shape
    • H01L2224/48091—Arched
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/481—Disposition
    • H01L2224/48151—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
    • H01L2224/48221—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
    • H01L2224/48245—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being metallic
    • H01L2224/48247—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being metallic connecting the wire to a bond pad of the item
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/15—Details of package parts other than the semiconductor or other solid state devices to be connected
    • H01L2924/181—Encapsulation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/48—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
    • H01L33/52—Encapsulations

Definitions

  • the present invention relates to a encapsulation manufacturing method of a light- emitting diode (LED), eliminating the need for mold and heating in a furnace during encapsulation manufacturing process of LED, prompting rapid curing thereof, and thereby enhancing the effectiveness in economizing on fabrication and labor, as well as enhancing production efficiency.
  • LED light- emitting diode
  • a method of encapsulation during the manufacturing process of LED is a manufacturing process to protect the LED in reliability. According to the prior art of manufacturing a LED, the manufacturing process is divided into the following steps:
  • An object of the present invention is to provide a method for the encapsulation of light-emitting diode without an involvement of mold as a solution for the aforementioned problems.
  • Another object of the present invention is to provide a method for the encapsulation of light-emitting diode without heating process and with rapid process time.
  • a method for the encapsulation of LED which comprises the steps of: a) dispensing the photosensitive epoxy; b) immersing the LED chip in the epoxy; c) injecting the current in the LED chip, thereby making the epoxy resins polymerized and forming an encapsulant with specific shape on the LED chip; and d) removing the unpolymerized epoxy from the LED lamp.
  • the photosensitive epoxy is exposed to the light emitted from the LED chip, thereby triggering a free radical polymerization reaction of the photosensitive epoxy, and rapid curing on the chip to form the specific polymerized cap, eliminating the need of mold and for heating process (baking) during encapsulation manufacturing process of LED, and thereby enhancing production efficiency.
  • the photosensitive epoxy composition of this invention comprises two essential ingredients.
  • the first essential ingredient is a photosensitive ethylenically unsaturated monomer selected from the group consisting of aryl acrylates and aryl methacrylates ("aryl acrylate monomers").
  • aryl acrylate monomers are aryl di- acrylates, triacrylates and tetra acrylates as for example di, tri and tetraacrylates based on benzene, naphthalene, bisphenol-A, biphenylene, methane biphenylene, trifluo- romethane biphenylene, phenoxyphenylene and the like.
  • the preferred aryl acrylate monomers are multifunctional aryl acrylates and methacrylates and more preferred aryl acrylate monomers are di, tri and tetra acrylates and methacrylates based on the bisphenol-A structure.
  • Most preferred aryl acrylate monomers are alkoxylated bisphenol-A diacrylates and dimethacrylates such as ethoxylated bisphenol-A di- acrylate and dimethacrylates, propoxylated bisphenol A diacrylates and dimethacrylates and ethoxylated hexafluorobisphenol-A diacrylates and dimethacrylates.
  • the aryl acrylate monomers of choice are ethoxylated bisphenol-A diacrylate and dimethacrylates.
  • the amount of aryl acrylate monomer in the composition may vary widely and amounts normally used in photosensitive epoxy compositions for use in the preparation of photopolymers for use as the light transmissive element of light transmissive devices may be used.
  • the amount of aryl acrylate monomer is usually from about 35 to about 99.9% by weight of the composition, preferably from about 60 to about 98% by weight of the composition and more preferably from about 65 to about 95% by weight of the composition.
  • the photosensitive epoxy includes a photoinitiator system which is activated by actinic radiation to produce activated species which lead to photo polymerization of the aryl acrylate monomer.
  • Photoinitiator is a compound which decompose the photosensitive epoxy into a free radical when it exposed to the light. The radicals induce polymerize of monomer and free polymer.
  • Preferred initiators are 1-hydroxy-cyclohexyl-phenyl ketone (Irgacurel84), benzoin, benzoin ethyl ether, benzoin isopropyl ether, benzophenone, benzidimethyl ketal (Irgacure 651), ⁇ , ⁇ -diethyloxy acetophenone, ⁇ , ⁇ -dimethyloxy- ⁇ -hydroxy acetophenone (Darocur 1173), l-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-propan-l-one (Darocur 2959), 2-methyl-l-[4-methylthio]phenyl]-2-morpholino-propan-l-one (Irgacure 907), 2-benzyl-2-dimethylamino-l-(4-morpholinophenyl)-butan-l-one (Irgacure 369), poly ⁇ l-[4-(l-
  • the more preferred photoinitiators includes benzidimethyl ketal (Irgacure 651), ⁇ , ⁇ -diethyloxy acetophenone, ⁇ , ⁇ -dimethyloxy- ⁇ -hydroxy acetophenone (Darocur 1173), 1-hydroxy-cyclohexyl-phenyl ketone (Irgacure 184), l-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-propan- 1-one (Darocur 2959), 2-methyl- 1-4- (methylthio)phenyl ⁇ -2-morpholino-propan- 1 -one (Irgacure 907) , 2-benzyl-2-dimethylamino- 1 - (4-morpholinophenyl)butan- 1 -one (Irgacure 369) .
  • the amount of photoinitiator may vary widely and conventional amounts may be used. Usually, the amount of photoinitiator is from about 0.1 to about 10 by weight of the composition. The amount of photoinitiator is preferably from about 0.5 to about 10% by weight, and more preferably from about 0.5 to about 5% by weight based on the total weight of the composition.
  • the purpose of the present invention could be achieved by composing photoinitiator sensitive to at least some of the light wavelength which is emitted from light-emitting diode.
  • the photoinitiator system may contain a photoinitiator and preferably a conventional sensitizer which extends the spectral response into regions having spectral utility, e.g. the near U.V. region and the visible spectral regions where lasers excite.
  • a Saline coupling agent may be added, thereby increasing degree of bonding strength among the materials; 0.01%.about.l5% of ultraviolet absorber agent may be added to increase resistance to ultraviolet light degradation; 0.01%.about.20% of Hindered Amine Light Stabilizer may be added to avoid free radical chemical structure destruction.
  • antioxidant is a substituted phenol selected from the group consisting of l,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl)-4-hydroxybenzyl)benzene; 1 , 1 ,3-tris-(2-methyl-4-hydroxy-5-tert-butylphenyl)butane; 4,4'-butylidene-bis-(6-tert-butyl-3-methylphenol); 4,4'-thiobis-(6-tert-butyl-3-methylphenol); tris- (3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate; cetyl- 3,5-di-tert-butyl-4-hydroxybenzene; 3,5-di-tert-butyl-4-hydroxybenzoic acid; 1 ,3,5-tris-tert-butyl-3-hydroxy-2,6-dimethylbenzyl; stearyl- 3-(3,
  • organic illuminant or mineral illuminant such as various fluorescent materials, semiconductor quantum dot, organic semiconductor
  • organic illuminant or mineral illuminant absorb some of or whole emitted light from the LED chip and re-emit secondary light. Therefore a method for encapsulating a LED emitting light with wide spectrum becomes possible.
  • metal minute particle may be included in the photosensitive epoxy composition.
  • the metal minute particle absorb, diffuse or amplify some of or whole emitted light from the LED.
  • organic illuminant or mineral illuminant such as various fluorescent materials, semiconductor quantum dot, organic semiconductor
  • metal minute particle metal nano/ micro particles
  • the organic illuminant or mineral illuminant absorb some of or whole emitted light from the LED chip and re-emit secondary light.
  • the invention enables us to manufacture a light emitting diode with a quality of multi- wavelength and improved efficiency by including organic illuminant or mineral illuminant and metal minute particle in various ways through the aforementioned method for encapsulating a light emitting diode.
  • the present invention provides effectiveness in economizing on fabrication and labor as well as enhancing productin efficiency by eliminating the need for mold and heating in a furnance during the encapsulation process, whereas in the prior art, the mold is indispensable.
  • FIG. 1 ?? FIG. 4 illustrate a method for the encapsulation of light-emitting diode according to an exemplary embodiment of the present invention.
  • FIG. 5 ?? FIG. 6 illustrate a various types of installation of light-emitting diode chip according to an exemplary embodiment of the present invention.
  • FIG. 7 ⁇ FIG. 8 shows the view before and after the manufacturing process for the encapsulation of light-emitting diode according to an experimental embodiment of the present invention.
  • FIG. 9 ⁇ FIG. 10 illustrates graphs showing beam profile of FIG. 7 and FIG. 8 each.
  • FIG.1 ⁇ FIG4 illustrate a method for the encapsulation of light-emitting diode according to an exemplary embodiment of the present invention.
  • the fluid epoxy 100 is dispensed into a mold (FIG. 1), the LED chips 10 are immersed in the photosensitive epoxy 100 (FIG. 2).
  • the current is injected in the LED chips 10 to make the chip 10 emitting light, the epoxy resins polymerized and forming an encapsulant 20 naturally with specific shape on the LED chip 10 (FIG. 3). That is to say, viscous fluid high molecule weight resin will be hardened and rapid cured on the chip to form the specific polymerized cap. Then the unpolymerized epoxy is removed from the LED lamp 100 (FIG. 4) and perform the cutting, testing and packaging process.
  • the present invention is characterized in having following particular distinctive features:
  • the present invention eliminates the involvement of mold in the encapsulation process by utilizing the light emitted from the LED chips 10.
  • the injected current could be DC or AC current, to obtain the desired LED lamp.
  • the photosensitive epoxy 100 is exposed to the light emitted from the LED chip 10, thereby triggering a free radical polymerization reaction of the photosensitive epoxy 100, and rapid curing on the chip 10 to form the specific polymerized cap 20.
  • the photosensitive epoxy 100 of the high molecule weight resin of the aforementioned encapsulant comprises a photosensitive epoxy constituting at least one of an Oligomer or a reactive Monomer, and a Photoinitiator.
  • the photosensitive epoxy 100 is exposed to light emitted from LED chip 10 for within 1 minute, thereby triggering a free radical polymerization reaction of the fluid photo-sensitive polymer, and rapid curing on the chip to form the specific polymerized cap, eliminating the need of mold and for baking during encapsulation manufacturing process of LED chip 100, and thereby enhancing production efficiency.
  • the present invention utilizes the aforementioned encapsulation manufacturing processes to complete LED finished product, while maintaining characteristics of hardness, curing speed, and resistance to ultraviolet degradation, which are clearly far superior than the LED produced by the other manufacturing process.
  • FIG. 5 ⁇ FIG. 6 illustrate a various types of installation of light-emitting diode chip according to an exemplary embodiment of the present invention.
  • Fig. 5 is illustrating the chip shaped LED.
  • the LED consists of electrode substrate 1 and the LED chip installed in the substrate.
  • the LED chip 2 is installed in the first electrode 3 and connected to the second electrode through wires 7.
  • FIG. 6 is illustrating the lamp shaped LED.
  • the LED ship 12 consists of the first lead terminal 13 including a reflection part at the tip and the second terminal 14 detached from the first lead terminal at some intervals.
  • the LED chip 12 is installed inside of the reflection part of the first lead terminal and the encapsulation is performed in the upper part of the LED chip to protect the LED chip 12.
  • the LED chip 12 is connected to the second lead terminal 14 through wires.
  • FIG. 7 ⁇ FIG. 8 shows the view before and after the manufacturing process for the encapsulation of light-emitting diode according to an experimental embodiment of the present invention.
  • a TO-CAN structure shows an example of a structure with the built-in LED chip.
  • the inserted picture is enlarged cut of the LED chip part.
  • the reflection part and wiring is also shown in the FIG 7.
  • the red scale bar in the inserted picture is the size of 0.1mm.
  • FIG. 8 it is shown that the photosensitive epoxy is exposed to the light emitted from the LED chip, thereby the epoxy is polymerized and form an en- capsulant with specific shape on the LED chip 10.
  • the inserted picture shows the manufacturing process that the LED chip is included inside the encapsulant by the the emitted light.
  • the shape of the substrates in which the LED chip is mounted is different. In this manner, a profile of the light emitted from the LED has a little different aspect if the substrates are a little different in their shape.
  • FIG. 9 and FIG. 10 illustrate graphs showing beam profile of FIG. 7 and FIG. 8 each.
  • the graph shows the change of beam profile when the different current is injected in the structure of FIG. 7.
  • the graph shows the change of beam profile when the different current is injected in the structure of FIG. 8.
  • the beam profile could be controlled by the shape of substrates and could be optimized by the alteration of the shape of encapsulation through the proper control of the beam profile.
  • the shape of encapsulation is altered by the amount of current and injected time in the LED.
  • the shape of encapsulation could be controlled by the current and time in the LED and the shape of substrates.

Abstract

The present invention relates to a encapsulation manufacturing method of a light-emitting diode (LED), which comprises the steps of dispensing the photosensitive epoxy; immersing the LED chip in the epoxy; injecting the current in the LED chip, thereby making the epoxy resins polymerized and forming an encapsulant with specific shape on the LED chip; and removing the unpolymerized epoxy from the LED lamp.

Description

Description
ENCAPSULATION METHOD OF LIGHT EMITTING DIODE
Technical Field
[1] The present invention relates to a encapsulation manufacturing method of a light- emitting diode (LED), eliminating the need for mold and heating in a furnace during encapsulation manufacturing process of LED, prompting rapid curing thereof, and thereby enhancing the effectiveness in economizing on fabrication and labor, as well as enhancing production efficiency. Background Art
[2] A method of encapsulation during the manufacturing process of LED is a manufacturing process to protect the LED in reliability. According to the prior art of manufacturing a LED, the manufacturing process is divided into the following steps:
[3] 1. Encapsulation: Upon injecting a thick, viscous, fluid epoxy resin into a mold, place LED chip into the mold.
[4] 2. Curing: Upon encapsulation, place encapsulant material into a heating furnace and heat it at a high temperature or give the irritation to the epoxy. Then viscous fluid high molecule weight resin will have hardened, thereby completing encapsulation.
[5] 3. Cutting, testing and packaging.
[6] The prior arts of manufacturing a LED are disclosed in U.S. Patent No. 6114090,
6583444, 6958250, 6507049, U.S. Publication Gazette No. 2001/0026011, 200300011140.
[7] However, in the encapsulation processes of the prior arts, since the lamp shape is controlled by the mold, a mold is certainly indispensable. The problem is that high price of the mold results in a cost for the encapsulation process.
[8] Furthermore, because of an enormous discrepancy between thermal expansion coefficients of the epoxy resin and the LED chips, during process of curing, cooling and shrinkage of the epoxy resin, internal stress may occur between the epoxy resin and the LED chips, engendering cracking of the epoxy resin, fracturing of the LED chips, separation of adhesion, shifting or splitting of component connected lead frames, etc. Disclosure of Invention
Technical Problem
[9] An object of the present invention is to provide a method for the encapsulation of light-emitting diode without an involvement of mold as a solution for the aforementioned problems. Another object of the present invention is to provide a method for the encapsulation of light-emitting diode without heating process and with rapid process time. Technical Solution
[10] As a technical solution for the aforementioned problems, according to a first aspect of the present invention, there is provided a method for the encapsulation of LED which comprises the steps of: a) dispensing the photosensitive epoxy; b) immersing the LED chip in the epoxy; c) injecting the current in the LED chip, thereby making the epoxy resins polymerized and forming an encapsulant with specific shape on the LED chip; and d) removing the unpolymerized epoxy from the LED lamp.
[11] The photosensitive epoxy is exposed to the light emitted from the LED chip, thereby triggering a free radical polymerization reaction of the photosensitive epoxy, and rapid curing on the chip to form the specific polymerized cap, eliminating the need of mold and for heating process (baking) during encapsulation manufacturing process of LED, and thereby enhancing production efficiency.
[12] The photosensitive epoxy composition of this invention comprises two essential ingredients. The first essential ingredient is a photosensitive ethylenically unsaturated monomer selected from the group consisting of aryl acrylates and aryl methacrylates ("aryl acrylate monomers"). Illustrative of such aryl acrylate monomers are aryl di- acrylates, triacrylates and tetra acrylates as for example di, tri and tetraacrylates based on benzene, naphthalene, bisphenol-A, biphenylene, methane biphenylene, trifluo- romethane biphenylene, phenoxyphenylene and the like. The preferred aryl acrylate monomers are multifunctional aryl acrylates and methacrylates and more preferred aryl acrylate monomers are di, tri and tetra acrylates and methacrylates based on the bisphenol-A structure. Most preferred aryl acrylate monomers are alkoxylated bisphenol-A diacrylates and dimethacrylates such as ethoxylated bisphenol-A di- acrylate and dimethacrylates, propoxylated bisphenol A diacrylates and dimethacrylates and ethoxylated hexafluorobisphenol-A diacrylates and dimethacrylates. The aryl acrylate monomers of choice are ethoxylated bisphenol-A diacrylate and dimethacrylates.
[13] The amount of aryl acrylate monomer in the composition may vary widely and amounts normally used in photosensitive epoxy compositions for use in the preparation of photopolymers for use as the light transmissive element of light transmissive devices may be used. The amount of aryl acrylate monomer is usually from about 35 to about 99.9% by weight of the composition, preferably from about 60 to about 98% by weight of the composition and more preferably from about 65 to about 95% by weight of the composition.
[14] As another essential component, the photosensitive epoxy includes a photoinitiator system which is activated by actinic radiation to produce activated species which lead to photo polymerization of the aryl acrylate monomer. Photoinitiator is a compound which decompose the photosensitive epoxy into a free radical when it exposed to the light. The radicals induce polymerize of monomer and free polymer. There are two kinds of photoinitiator which are free radical and ionic photoinitiator. Preferred initiators are 1-hydroxy-cyclohexyl-phenyl ketone (Irgacurel84), benzoin, benzoin ethyl ether, benzoin isopropyl ether, benzophenone, benzidimethyl ketal (Irgacure 651), α, α-diethyloxy acetophenone, α, α-dimethyloxy-α-hydroxy acetophenone (Darocur 1173), l-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-propan-l-one (Darocur 2959), 2-methyl-l-[4-methylthio]phenyl]-2-morpholino-propan-l-one (Irgacure 907), 2-benzyl-2-dimethylamino-l-(4-morpholinophenyl)-butan-l-one (Irgacure 369), poly{ l-[4-(l-methylvinyl)phenyll-2-hydroxy-2-methyl-propan-l-one] (Esacure KIP), [4-(4-methylphenylthio)-phenyl]phenylmethanone (Quantacure BMS), di-campherquinone. The more preferred photoinitiators includes benzidimethyl ketal (Irgacure 651), α, α-diethyloxy acetophenone, α, α-dimethyloxy-α-hydroxy acetophenone (Darocur 1173), 1-hydroxy-cyclohexyl-phenyl ketone (Irgacure 184), l-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-propan- 1-one (Darocur 2959), 2-methyl- 1-4- (methylthio)phenyl } -2-morpholino-propan- 1 -one (Irgacure 907) , 2-benzyl-2-dimethylamino- 1 - (4-morpholinophenyl)butan- 1 -one (Irgacure 369) .
[15] The amount of photoinitiator may vary widely and conventional amounts may be used. Usually, the amount of photoinitiator is from about 0.1 to about 10 by weight of the composition. The amount of photoinitiator is preferably from about 0.5 to about 10% by weight, and more preferably from about 0.5 to about 5% by weight based on the total weight of the composition.
[16] The purpose of the present invention could be achieved by composing photoinitiator sensitive to at least some of the light wavelength which is emitted from light-emitting diode. Also the photoinitiator system may contain a photoinitiator and preferably a conventional sensitizer which extends the spectral response into regions having spectral utility, e.g. the near U.V. region and the visible spectral regions where lasers excite.
[17] In addition, when implementing the present invention, 0. l%.about.20% of a Saline coupling agent may be added, thereby increasing degree of bonding strength among the materials; 0.01%.about.l5% of ultraviolet absorber agent may be added to increase resistance to ultraviolet light degradation; 0.01%.about.20% of Hindered Amine Light Stabilizer may be added to avoid free radical chemical structure destruction.
[18] Preferably, antioxidant may be added, antioxidant is a substituted phenol selected from the group consisting of l,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl)-4-hydroxybenzyl)benzene; 1 , 1 ,3-tris-(2-methyl-4-hydroxy-5-tert-butylphenyl)butane; 4,4'-butylidene-bis-(6-tert-butyl-3-methylphenol); 4,4'-thiobis-(6-tert-butyl-3-methylphenol); tris- (3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate; cetyl- 3,5-di-tert-butyl-4-hydroxybenzene; 3,5-di-tert-butyl-4-hydroxybenzoic acid; 1 ,3,5-tris-tert-butyl-3-hydroxy-2,6-dimethylbenzyl; stearyl- 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate; pentaerythritol- tetrabis(3,5-di-tert-butyl-4-hydroxyphenyl); and thiodiethylene- bis-(3,5-di-tert-butyl-4-hydroxy)hydrocinnamate.
[19] On the one hand, singular or plural organic illuminant or mineral illuminant (such as various fluorescent materials, semiconductor quantum dot, organic semiconductor) may be included in the photosensitive epoxy composition. The above organic illuminant or mineral illuminant absorb some of or whole emitted light from the LED chip and re-emit secondary light. Therefore a method for encapsulating a LED emitting light with wide spectrum becomes possible.
[20] On the other hand, singular or plural metal minute particle (metal nano/ micro particles) may be included in the photosensitive epoxy composition. The metal minute particle absorb, diffuse or amplify some of or whole emitted light from the LED.
[21] Also, singular or plural organic illuminant or mineral illuminant (such as various fluorescent materials, semiconductor quantum dot, organic semiconductor) and metal minute particle (metal nano/ micro particles) may be included in the photosensitive epoxy composition. The organic illuminant or mineral illuminant absorb some of or whole emitted light from the LED chip and re-emit secondary light.
[22] Therefore, the invention enables us to manufacture a light emitting diode with a quality of multi- wavelength and improved efficiency by including organic illuminant or mineral illuminant and metal minute particle in various ways through the aforementioned method for encapsulating a light emitting diode.
Advantageous Effects
[23] The present invention provides effectiveness in economizing on fabrication and labor as well as enhancing productin efficiency by eliminating the need for mold and heating in a furnance during the encapsulation process, whereas in the prior art, the mold is indispensable.
Brief Description of the Drawings [24] FIG. 1 ~ FIG. 4 illustrate a method for the encapsulation of light-emitting diode according to an exemplary embodiment of the present invention. [25] FIG. 5 ~ FIG. 6 illustrate a various types of installation of light-emitting diode chip according to an exemplary embodiment of the present invention. [26] FIG. 7 ~ FIG. 8 shows the view before and after the manufacturing process for the encapsulation of light-emitting diode according to an experimental embodiment of the present invention.
[27] FIG. 9 ~ FIG. 10 illustrates graphs showing beam profile of FIG. 7 and FIG. 8 each.
Mode for the Invention
[28] FIG.1 ~ FIG4 illustrate a method for the encapsulation of light-emitting diode according to an exemplary embodiment of the present invention.
[29] First, the fluid epoxy 100 is dispensed into a mold (FIG. 1), the LED chips 10 are immersed in the photosensitive epoxy 100 (FIG. 2).
[30] Next, the current is injected in the LED chips 10 to make the chip 10 emitting light, the epoxy resins polymerized and forming an encapsulant 20 naturally with specific shape on the LED chip 10 (FIG. 3). That is to say, viscous fluid high molecule weight resin will be hardened and rapid cured on the chip to form the specific polymerized cap. Then the unpolymerized epoxy is removed from the LED lamp 100 (FIG. 4) and perform the cutting, testing and packaging process.
[31] The present invention is characterized in having following particular distinctive features: The present invention eliminates the involvement of mold in the encapsulation process by utilizing the light emitted from the LED chips 10. The injected current could be DC or AC current, to obtain the desired LED lamp.
[32] In the present invention, the photosensitive epoxy 100 is exposed to the light emitted from the LED chip 10, thereby triggering a free radical polymerization reaction of the photosensitive epoxy 100, and rapid curing on the chip 10 to form the specific polymerized cap 20.
[33] The photosensitive epoxy 100 of the high molecule weight resin of the aforementioned encapsulant comprises a photosensitive epoxy constituting at least one of an Oligomer or a reactive Monomer, and a Photoinitiator.
[34] After a LED chip encapsulation, the photosensitive epoxy 100 is exposed to light emitted from LED chip 10 for within 1 minute, thereby triggering a free radical polymerization reaction of the fluid photo-sensitive polymer, and rapid curing on the chip to form the specific polymerized cap, eliminating the need of mold and for baking during encapsulation manufacturing process of LED chip 100, and thereby enhancing production efficiency.
[35] The present invention utilizes the aforementioned encapsulation manufacturing processes to complete LED finished product, while maintaining characteristics of hardness, curing speed, and resistance to ultraviolet degradation, which are clearly far superior than the LED produced by the other manufacturing process.
[36] Of primary note is in the manufacturing process as disclosed in the present invention, whereby, during the encapsulation, the fluid photosensitive epoxy resin only requires exposure to light emitted from LED chip for within 1 minute without the need of mold, whereupon prompt curing occurs under room temperature. Whereas, in the popular manufacturing process, there is a requirement for mold and heating in furnace during the encapsulation. Clearly, the present invention has achieved effectiveness in economizing on fabrication and labor, as well as enhancing production efficiency.
[37] FIG. 5 ~ FIG. 6 illustrate a various types of installation of light-emitting diode chip according to an exemplary embodiment of the present invention.
[38] Fig. 5 is illustrating the chip shaped LED. The LED consists of electrode substrate 1 and the LED chip installed in the substrate. The LED chip 2 is installed in the first electrode 3 and connected to the second electrode through wires 7. In the upper part of the LED chip 2 there is a necessity of encapsulation as mentioned above to protect the LED chip 2.
[39] FIG. 6 is illustrating the lamp shaped LED. The LED ship 12 consists of the first lead terminal 13 including a reflection part at the tip and the second terminal 14 detached from the first lead terminal at some intervals. The LED chip 12 is installed inside of the reflection part of the first lead terminal and the encapsulation is performed in the upper part of the LED chip to protect the LED chip 12. The LED chip 12 is connected to the second lead terminal 14 through wires.
[40] FIG. 7 ~ FIG. 8 shows the view before and after the manufacturing process for the encapsulation of light-emitting diode according to an experimental embodiment of the present invention.
[41] Referring to the FIG. 7, a TO-CAN structure shows an example of a structure with the built-in LED chip. The inserted picture is enlarged cut of the LED chip part. The reflection part and wiring is also shown in the FIG 7. The red scale bar in the inserted picture is the size of 0.1mm.
[42] Referring to the FIG. 8, it is shown that the photosensitive epoxy is exposed to the light emitted from the LED chip, thereby the epoxy is polymerized and form an en- capsulant with specific shape on the LED chip 10. The inserted picture shows the manufacturing process that the LED chip is included inside the encapsulant by the the emitted light.
[43] In the FIG. 7 and FIG. 8, the shape of the substrates in which the LED chip is mounted is different. In this manner, a profile of the light emitted from the LED has a little different aspect if the substrates are a little different in their shape.
[44] FIG. 9 and FIG. 10 illustrate graphs showing beam profile of FIG. 7 and FIG. 8 each.
[45] Referring to the FIG. 9, the graph shows the change of beam profile when the different current is injected in the structure of FIG. 7. Referring to the FIG. 10, the graph shows the change of beam profile when the different current is injected in the structure of FIG. 8. [46] According to the FIG. 9 and FIG. 10, the beam profile could be controlled by the shape of substrates and could be optimized by the alteration of the shape of encapsulation through the proper control of the beam profile. The shape of encapsulation is altered by the amount of current and injected time in the LED.
[47] Accordingly, the shape of encapsulation could be controlled by the current and time in the LED and the shape of substrates.
[48] The present invention is alterable without escape from the idea and range of the present invention. Accordingly, the above explanation of an exemplary embodiment of the present invention will be provided only for purpose of illustration, not be provided for the purpose of limitation of the present invention limited by the attached claims and their equivalent.

Claims

Claims
[1] A manufacturing method for encapsulating a LED lamp, which comprises the steps of a) dispensing the photosensitive epoxy; b) immersing the LED chip in the epoxy; c) injecting the current in the LED chip, thereby making the epoxy resins polymerized and forming an encapsulant with specific shape on the LED chip; and d) removing the unpolymerized epoxy from the LED lamp
[2] A manufacturing method for encapsulating a LED lamp according to claim 1, wherein the photosensitive epoxy resins includes an Oligomer and a Pho- toinitiator.
[3] A manufacturing method for encapsulating a LED lamp according to claim 1, wherein the photosensitive epoxy resins includes a reactive Monomer, and a Photoinitiator.
[4] A manufacturing method for encapsulating a LED lamp according to claim 1, wherein the photoinitiator is sensitive to the light wavelength emitted from the LED chip.
[5] A manufacturing method for encapsulating a LED lamp according to claim 1, wherein the photosensitive epoxy comprises a sensitizer expanding the spectrum reaction of the photosensitive epoxy.
[6] A manufacturing method for encapsulating a LED lamp according to claim 1, wherein the photosensitive epoxy includes at least one selected from the group consisting of between 0.1% and 20% of a Silane coupling agent, 0.01% and 15% of an ultraviolet absorber agent, and between 0.01% and 20% of a Hindered Amine Light Stabilizer.
[7] A manufacturing method for encapsulating a LED lamp according to claim 1, wherein the photosensitive epoxy composition comprising one or more unsaturated monomers selected from the group consisting of 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, ethoxylated trimethylolpropane triacrylate, glyceryl, propoxylated triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate and di(trimethylolpropane) tetraacrylate, and at least one photoinitiator capable of activating polymerization of said monomers when said photopolymerizable composition is exposed to actinic radiation the method comprising incorporating into said photopolymerizable composition from about 35% to about 99.9% by weight of the photopolymerizable composition of at least one ethylenically unsaturated monomer selected from the group consisting of ethoxylated bisphenol A diacrylate, ethoxylated hexafluorobisphenol.
[8] A manufacturing method for encapsulating a LED lamp according to claim 1, wherein said photoinitiator is a photoinitiator selected from the group consisting of benzidimethyl ketal; α, α-dimethyloxy-α-hydroxy acetophenone; 1-hydroxy-cyclohexyl-phenyl ketone; l-[4-(2-hydroxyethoxy)phenyl] - 2-hydroxy-2-methyl-propan-l-one; benzophenone; benzoin; benzoin ethyl ether; benzoin isopropyl ether; α, α-diethyloxy acetophenone; 2-methyl- 1 - [4-methylthio]phenyl] -2-morpholino-propan- 1 -one; 2-benzyl-2-dimethylamino- 1 -(4-morpholinophenyl)-butan- 1 -one; poly { 1 - [4-( 1 -methyl vinyl)phenyl] 2-methyl-propan- 1 -one; [4-(4-methylphenylthio)-phenyl]phenylmethanonone; and di-campherquinone.
[9] A manufacturing method for encapsulating a LED lamp according to claim 1, wherein said photoinitiator is a photoinitiator selected from the group consisting of benzidimethyl ketal; α, α-dimethyloxy-α-hydroxy acetophenone; 1-hydroxy-cyclohexyl-phenyl ketone; l-[4-(2-hydroxyethoxy)phenyl] - 2-hydroxy-2-methyl-propan-l-one; benzophenone; benzoin; benzoin ethyl ether; benzoin isopropyl ether; α, α-diethyloxy acetophenone; 2-methyl- 1 - [4-methylthio]phenyl] -2-morpholino-propan- 1 -one; 2-benzyl-2-dimethylamino- 1 - (4-morpholinophenyl)-butan- 1 -one.
[10] A manufacturing method for encapsulating a LED lamp according to claim 1, wherein said photoinitiator is selected from the group consisting of benzidimethyl ketal; α, α-diethyloxy acetophenone; α, α-dimethyloxy-α-hydroxy acetopheneone; 1-hydroxy-cyclohexyl-phenyl ketone; l-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-propan-l-one; benzophenone.
[11] A manufacturing method for encapsulating a LED lamp according to claim 1, A manufacturing process for encapsulating a LED lamp according to claim 1, wherein said photosensitive epoxy composition further comprises an additional aliphatic ethylenically unsaturated monomer.
[12] A manufacturing method for encapsulating a LED lamp according to claim 11, wherein said aliphatic ethylenically unsaturated monomer is selected from the group consisting of aliphatic acrylate monomers and aliphatic methacrylate monomers.
[13] A manufacturing method for encapsulating a LED lamp according to claim 11, wherein said aliphatic ethylenically unsaturated monomer is selected from the group consisting of aliphatic diacrylates, aliphatic triacrylates, aliphatic tetraacrylates, aliphatic dimethacrylates, aliphatic trimethacrylates, and aliphatic tetramethacrylates .
[14] A manufacturing method for encapsulating a LED lamp according to claim 1, wherein said antioxidant is a substituted phenol selected from the group consisting of l,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl)-4-hydroxybenzyl)benzene; 1 , 1 ,3-tris-(2-methyl-4-hydroxy-5-tert-butylphenyl)butane; 4,4'-butylidene-bis-(6-tert-butyl-3-methylphenol); 4,4'-thiobis-(6-tert-butyl-3-methylphenol); tris- (3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate; cetyl- 3,5-di-tert-butyl-4-hydroxybenzene; 3,5-di-tert-butyl-4-hydroxybenzoic acid; 1 ,3,5-tris-tert-butyl-3-hydroxy-2,6-dimethylbenzyl; stearyl- 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate; pentaerythritol- tetrabis(3,5-di-tert-butyl-4-hydroxyphenyl); and thiodiethylene- bis-(3,5-di-tert-butyl-4-hydroxy)hydrocinnamate
[15] A manufacturing method for encapsulating a LED lamp according to claim 1, wherein a LED emits light with various wavelength and wide spectrum by including singular or plural organic illuminant or mineral illuminant in the photosensitive epoxy composition therefore some of or whole emitted light from the light emitting diode chip is absorbed and the above organic illuminant or mineral illuminant re-emit secondary light.
[16] A manufacturing method for encapsulating a LED lamp according to claim 1, wherein metal minute particle absorb, diffuse or amplify some of or whole emitted light from the LED by including singular or plural metal minute particle (metal nano/ micro particles) in the photosensitive epoxy composition.
[17] A manufacturing method for encapsulating a LED lamp according to claim 1, wherein organic illuminant or mineral illuminant absorb some of or whole emitted light from the LED chip and re-emit secondary light, then the some of or whole emitted light from the LED chip and organic illuminant or mineral illuminant absorb, diffuse or amplify re-emitted light by including singular or plural organic illuminant or mineral illuminant and metal minute particle in the photosensitive epoxy composition.
PCT/KR2008/000775 2007-02-08 2008-02-11 Encapsulation method of light emitting diode WO2008097055A1 (en)

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US9647200B1 (en) 2015-12-07 2017-05-09 International Business Machines Corporation Encapsulation of magnetic tunnel junction structures in organic photopatternable dielectric material

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06232458A (en) * 1993-02-08 1994-08-19 Sharp Corp Manufacture of light-emitting diode
US6018167A (en) * 1996-12-27 2000-01-25 Sharp Kabushiki Kaisha Light-emitting device
US6114090A (en) * 1993-07-01 2000-09-05 Corning Incorporated Thermally-stable photopolymer composition and light transmissive device
US6958250B2 (en) * 2003-08-26 2005-10-25 Yung-Shu Yang Light-emitting diode encapsulation material and manufacturing process

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06232458A (en) * 1993-02-08 1994-08-19 Sharp Corp Manufacture of light-emitting diode
US6114090A (en) * 1993-07-01 2000-09-05 Corning Incorporated Thermally-stable photopolymer composition and light transmissive device
US6018167A (en) * 1996-12-27 2000-01-25 Sharp Kabushiki Kaisha Light-emitting device
US6958250B2 (en) * 2003-08-26 2005-10-25 Yung-Shu Yang Light-emitting diode encapsulation material and manufacturing process

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