(12) Ulllted States Patent
`Liu et al.
`
`(10) Patent N0.:
`(45) Date of Patent:
`
`US 6,593,011 B2
`Jul. 15, 2003
`
`US006593011B2
`
`(54) LIGHT EMITTING DIODE AND METHOD
`FOR MAKING THE SAME
`
`(75)
`
`Inventors: Ru-Shi Liu, Taipei Hsien (TW);
`Chien-Yuan Wang, Taipei Hsien (TW);
`Ting-Shan Chan, Taipei Hsien (TW);
`Jefi'rey Su, Taipei Hsien (TW);
`Michael Hsing, Taipei Hsien (TW)
`
`..... .. 118/716
`3/1992 Simopoulos et al.
`5,094,185 A *
`5,688,318 A * 11/1997 Milstein et al.
`.............. .. 117/1
`6,162,553 A * 12/2000 Ercoli
`...................... .. 428/690
`6,207,077 B1 *
`3/2001 Burnell—J0nes
`...... .. 252/301.36
`
`FOREIGN PATENT DOCUMENTS
`
`JP
`
`06349580
`
`,. 12/1994
`
`(73) Assignee: Lite-On Electronics, Inc., Taipei Hsien
`(TW)
`
`.
`.
`* cited by examiner
`
`( * ) Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 8 days.
`
`(21) Appl. No.: 09/910,891
`
`(22)
`
`Filed:
`
`Jul. 24, 2001
`
`(65)
`
`Prior Publication Data
`
`Us 2003/0099859 A1 May 29> 2003
`Int. Cl.7 ........................ .. H05B 33/14, H05B 33/20
`(51)
`(52) U.S. Cl.
`..................... .. 428/690; 428/917; 313/506;
`313/509; 252/301.4 R; 427/66
`Of Search ............................... ..
`313/506> 509; 252/3014 R; 427/66
`
`(56)
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`.
`.
`.
`Primary Examiner—CYl1lh1a H~ Kelly
`Assistant Examiner—DaWn Garrett
`(74) Attorney, Agent, or Firm—Rosenberg, Klein & Lee
`
`(57)
`
`ABSTRACT
`
`Alight emitting diode and a method for making the same are
`.
`.
`.
`proposed. The LED comprises an inorganic phosphor, a
`silicon compound and an organic glue. The silicon com-
`pound has one side being completely or partially C1-C6
`alkyl oxide reacted With the inorganic phosphor to modify
`the surface property of the inorganic phosphor and another
`Side being a functional grgnp Selected from a group Con-
`sisting of epoxy, C1-C6 alkyl, phenyl, amino. The inorganic
`phosphor with modified surface property can be uniformly
`.
`.
`.
`.
`.
`mixed in the glue and less deposition 1S produced.
`
`4,855,189 A *
`
`8/1989 Simopoulos et al.
`
`..... .. 428/690
`
`10 Claims, 2 Drawing Sheets
`
`Valeo Exhibit 1011_001
`
`Valeo Exhibit 1011_001
`
`

`
`U.S. Patent
`
`Jul. 15, 2003
`
`Sheet 1 012
`
`US 6,593,011 B2
`
`/ 1
`
`3
`
`
`
`
`12
`
`11
`
`
`
`
`122
`
`121
`
`functional group
`
`C 1-0 6 alkyl oxide
`
`inorganic phosphor
`
`FIG.1
`
`Valeo Exhibit 1011_002
`
`Valeo Exhibit 1011_002
`
`

`
`U.S. Patent
`
`Jul. 15, 2003
`
`Sheet 2 of2
`
`US 6,593,011 B2
`
`deposition height (mm)
`
`
`
`0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 time(hour)
`
`FIG.2
`
`Valeo Exhibit 1011_003
`
`Valeo Exhibit 1011_003
`
`

`
`US 6,593,011 B2
`
`1
`LIGHT EMITTING DIODE AND METHOD
`FOR MAKING THE SAME
`
`FIELD OF THE INVENTION
`
`The present invention relates to a light emitting diode and
`the method for making the same, especially to a light
`emitting diode with inorganic phosphor having modified
`surface property to enhance yield.
`
`BACKGROUND OF THE INVENTION
`
`The white light LED developed by Nichia company is
`composed of a blue LED generally made of InGaN and a
`yellow inorganic phosphor made of YAG (yttrium aluminum
`garnet). The yellow inorganic phosphor is excited by blue
`light from the blue LED and emits yellow light, which is
`mixed with the blue light to generate white light. The white
`light LED typically shows a color temperature of 8000 K at
`a forward current of 20 mA. The color rendering index (CRI)
`of the white light LED is comparable with the fluorescent
`lamp and the efficiency of the white light LED is comparable
`with light bulb (5-10 lm/W) and fluorescent lamp (10-30
`lm/W).
`In comparison with the LED set composed of three
`primitive colors (red, green and blue), the white light LED
`using yellow phosphor has advantages of simple structure
`and low cost. The color degradation probability due to
`failure of LED of respective color can be reduced. The white
`light LED is a light source with high directiveness and can
`be used for vehicle panel lighting, backlight of LCD, room
`lightening, notebook computer display, scanner, FAX, pro-
`jector and cellulous phone.
`The white light LED also has the advantages of
`compactness,
`long life,
`low current/voltage, no thermal
`radiation, and power saving and is expected as light source
`replacement for conventional light bulb.
`The yellow YAG phosphor in the white light LED of
`Nichia company is firstly mixed with resin with suitable
`ratio and is then packaged with a blue LED. The yellow
`YAG phosphor is an inorganic compound, which is hard to
`mix with the organic resin. Moreover, the weight ratio of the
`yellow YAG phosphor and the organic resin is also large
`such that it is hard for the yellow YAG phosphor powder to
`suspend in the organic resin.
`To overcome above problem, resin of high viscosity or
`other type of glue are used to mix with the YAG phosphor.
`The glue can be classified into two types, inorganic and
`organic. For example silicone is an inorganic glue with high
`viscosity. However, the transparency is only 80% and the
`applicability thereof is limited. For organic glue such as
`epoxy resin, the epoxy resin with high viscosity is commer-
`cially available with lower price. However, the allowable
`processing time is short.
`The above-mentioned glues with high viscosity can pre-
`vent the phosphor powder from deposition. However, the
`above-mentioned glues have following drawbacks:
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`2
`
`(1) The glues with high viscosity cannot be mixed uni-
`formly with the phosphor powder.
`(2) For the glues with high viscosity, the amount thereof
`is hard to control and the yield is influenced.
`
`SUMMARY OF THE INVENTION
`
`It is the object of the present invention to provide an LED
`to overcome above problems and having enhanced yield and
`brightness.
`To achieve above object, the present invention provides
`an LED comprising an inorganic phosphor, a silicon com-
`pound and an organic glue. The silicon compound has one
`side being completely or partially C1-C6 alkyl oxide reacted
`with the inorganic phosphor to modify the surface property
`of the inorganic phosphor and another side being a func-
`tional group selected from a group consisting of epoxy,
`C1-C6 alkyl, phenyl, amino. The inorganic phosphor with
`modified surface property can be uniformly mixed in the
`glue and less deposition is produced.
`The various objects and advantages of the present inven-
`tion will be more readily understood from the following
`detailed description when read in conjunction with the
`appended drawing, in which:
`
`BRIEF DESCRIPTION OF DRAWINGS
`
`FIG. 1 shows the structure of the present invention; and
`FIG. 2 shows the deposition height comparison for the
`present invention.
`
`DETAILED DESCRIPTION OF THE PRESENT
`INVENTION
`
`With reference now to FIG. 1, the LED according to the
`present invention comprises an inorganic phosphor 11, a
`silicon compound 12 and an organic glue 13. The inorganic
`phosphor 11 can be selected from the group consisting of
`YAG, oxide, sulfide, and phosphate. The inorganic phosphor
`11 has one side 121 being completely or partially C1-C6
`alkyl oxide reacted with the inorganic phosphor 11 to modify
`the surface property of the inorganic phosphor 11. The
`C1-C6 alkyl oxide can be either methoxy or ethyloxy and
`preferably be methoxy. The inorganic phosphor 11 has
`another side 122 being a functional group 122 reacted with
`the organic glue 13. The functional group can be selected
`from a group consisting of epoxy, C1-C6 alkyl, phenyl,
`amino and is preferably epoxy. The inorganic phosphor 11
`with modified surface can be uniformly distributed in the
`glue 13 and not easily deposited. The process is stable to
`enhance yield. The glue 13 can be selected from a group
`consisting epoxy resin, phenolic resin, polyurethane resin,
`amino resin and polyester resin.
`Table 1 shows the preferred embodiment of the present
`invention, the inorganic phosphor 11 is a YAG phosphor 11,
`the silicon compound 12 is a alkyl oxide containing silicon,
`such as y-glycidoxypropyl (dimethoxy) methylsilane, and
`the glue 13 is an epoxy resin.
`
`Valeo Exhibit 1011_004
`
`Valeo Exhibit 1011_004
`
`

`
`US 6,593,011 B2
`
`TABLE 1
`
`_
`-CH30
`H’
`_H+
`
`H
`
`O
`
`H
`
`H
`
`H
`H
`
`O
`
`H
`H
`
`H
`
`H
`
`H
`H
`
`H
`
`H
`.
`/s1%<
`0
`H H\
`
`0
`
`H
`
`H
`H
`s1
`s1
`/ Y \
`o
`0
`H
`
`H
`
`1
`
`\
`
`1
`
`/
`
`1
`
`O/Y\O/A \OZY\O/A \O/Y\O/A \OH
`
`H
`
`H
`
`H
`
`O
`H
`
`0
`
`H
`
`H
`
`H
`
`H
`
`H
`
`H
`
`H
`
`H
`
`H
`
`0
`
`H
`
`H
`
`H
`
`H
`
`H
`
`O
`
`H
`
`H
`
`H
`
`H
`
`The outer surface of the YAG phosphor 11 is in contact
`with the water molecule in air and hydroxyl is present on the
`outer surface thereof. The hydroxyl on the outer surface of
`the YAG phosphor 11 is reacted with the silicon alkyl oxide
`such that the alkyl oxide is divagated and the oxygen in the
`hydroxyl is reacted with silicon to form a compound with Y
`(or Al)—O—Si binding. The binding is a covalent binding
`with strong binding force such that the YAG phosphor 11 is
`firmly attached with the silicon compound 12.
`In above-mentioned surface modifying process, 2 g of
`YAG phosphor and 0.15 g of alkyl oxide containing silicon
`are mixed in 100 ml of 95% alcoholic solution. The mixed
`solution is supersonic shocked for 10 min and heated at 70°
`C. for 1 hr. The precipitation of the solution is removed by
`sifting and washed by ethyl alcohol. The solution is then
`dried at 85° C.
`to obtain YAG phosphor powder with
`modified surface.
`
`Another side of the silicon alkyl oxide 12 is a functional
`group resoluble in organic solution. The silicon alkyl oxide
`12 with modified surface can be easily reacted with epoxy
`resin and the link reaction between the silicon alkyl oxide 12
`and the epoxy resin enhances the stability of YAG phosphor
`resolved in the epoxy resin and reduces deposit. The YAG
`phosphor can be uniformly mixed in the epoxy resin to
`enhance yield.
`For comparison, 2 g of YAG phosphor with surface
`treatment and 2 g of YAG phosphor without surface treat-
`ment are mixed with 10 g of epoxy resin, respectively and
`the timing diagram for deposition height is shown in FIG. 2.
`As shown in this figure, after 6.5 hours, the deposition height
`of the YAG phosphor with surface treatment is 1 mm as
`indicated by solid line, and the deposition height of the YAG
`phosphor without surface treatment is 2 mm as indicated by
`dashed line. The deposition height is an index for non-
`uniform mixing. Therefore, the YAG phosphor with surface
`treatment proposed by the present invention can be uni-
`formly mixed with epoxy resin.
`For comparison, the YAG phosphor with surface treat-
`ment and the YAG phosphor without surface treatment are
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`mixed with epoxy resin, respectively and then packaged
`with a blue LED to assemble a white LED. The brightness
`for the white LED composed YAG phosphor with surface
`treatment is enhanced over the white LED composed YAG
`phosphor without surface treatment by 4—6%.
`To sum up, YAG phosphor 11 with surface treatment can
`be uniformly mixed in glue 13 and the link reaction ther-
`ebetween enhance compactness. The deposition is reduced
`and the yield is enhanced.
`Although the present invention has been described with
`reference to the preferred embodiment thereof, it will be
`understood that the invention is not limited to the details
`
`thereof. Various substitutions and modifications have sug-
`gested in the foregoing description, and other will occur to
`those of ordinary skill in the art. Therefore, all such substi-
`tutions and modifications are intended to be embraced
`
`within the scope of the invention as defined in the appended
`claims.
`We claim:
`
`1. A light emitting diode, comprising:
`an inorganic phosphor;
`a silicon compound having one side being at least par-
`tially C1-C6 alkyl oxide reacted with the inorganic
`phosphor to modify the surface property of the inor-
`ganic phosphor, and another side including a functional
`group selected from a group consisting of epoxy,
`C1-C6 alkyl, phenyl, and amino; and
`an organic glue reacted with the functional group;
`the phosphor and the silicon compound forming an ultra-
`sonically induced chemical bond one with the other;
`whereby the inorganic phosphor with modified surface
`property can be uniformly combined with the glue.
`2. The light emitting diode as in claim 1, wherein the
`inorganic phosphor can be selected from the group consist-
`ing of YAG (yttrium aluminum garnet), an oxide, a sulfide,
`and a phosphate.
`3. The light emitting diode as in claim 1, wherein the
`C1-C6 alkyl oxide can be either methoxy or ethyloxy.
`
`Valeo Exhibit 1011_005
`
`Valeo Exhibit 1011_005
`
`

`
`US 6,593,011 B2
`
`5
`4. The light emitting diode as in claim 1, wherein the glue
`can be selected from a group consisting of epoxy resin,
`phenolic resin, polyurethane resin, amino resin and polyester
`resin.
`
`5. A manufacturing method for light emitting diode,
`comprising the steps of:
`(a) preparing an inorganic phosphor;
`(b) mixing the inorganic phosphor with a silicon com-
`pound in an alcoholic solution to form a mixed solu-
`tion;
`
`(c) ultrasonically shocking and thereafter heating the
`mixed solution, the inorganic phosphor being respon-
`siVely reacted with a silicon alkyl oxide to form a
`surface modified phosphor;
`(d) mixing the surface modified phosphor with an organic
`glue, the phosphor being thereby uniformly suspended
`within the organic glue.
`6. The manufacturing method for light emitting diode as
`in claim 5, wherein in step (a) the inorganic phosphor can be
`selected from the group consisting of YAG (yttrium alumi-
`num garnet), an oxide, a sulfide, and a phosphate.
`
`6
`7. The manufacturing method for light emitting diode as
`in claim 5, wherein in step (b) the silicon compound has one
`side being at least partially C1-C6 alkyl oxide reacted with
`the inorganic phosphor to modify the surface property of the
`inorganic phosphor, and another side including a functional
`group selected from a group consisting of epoxy, C1-C6
`alkyl, phenyl, and amino.
`8. The manufacturing method for light emitting diode as
`in claim 7, wherein the C1-C6 alkyl oxide can be either
`methoxy or ethyloxy.
`9. The manufacturing method for light emitting diode as
`in claim 5, wherein in step (c), the glue can be selected from
`a group consisting epoxy resin, phenolic resin, polyurethane
`resin, amino resin and polyester resin.
`10. The manufacturing method for light emitting diode as
`in claim 7, wherein the inorganic phosphor is chemically
`bonded at the side of the silicon compound with C1-C6
`alkyl oxide.
`
`10
`
`15
`
`20
`
`Valeo Exhibit 1011_006
`
`Valeo Exhibit 1011_006