111111
`
`1111111111111111111111111111111111111111111111111111111111111
`US007652297B2
`
`c12) United States Patent
`Hon et al.
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 7,652,297 B2
`Jan.26,2010
`
`(54) LIGHT EMITTING DEVICE
`
`(75)
`
`Inventors: Lee Kee Hon, Penang (MY); Tan
`Kheng Leng, Fort Collins, CO (US);
`Lee Chiau Jin, Fort Collins, CO (US);
`Ng Keat Chuan, Fort Collins, CO (US);
`Oon Slang Ling, Fort Collins, CO (US);
`Ong Klam Soon, Fort Collins, CO (US)
`
`(73) Assignee: Avago Technologies ECBU IP
`(Singapore) Pte. Ltd., Singapore (SG)
`
`( *) Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 103 days.
`
`(21) Appl. No.: 11/853,179
`
`(22) Filed:
`
`Sep. 11, 2007
`
`(65)
`
`Prior Publication Data
`
`US 2009/0065793 Al
`
`Mar. 12, 2009
`
`(51)
`
`Int. Cl.
`HOJL 27115
`(2006.01)
`(52) U.S. Cl. ........................... 257/81; 257/99; 257/100;
`257/E33.056; 257/E25.032; 257/98
`
`(58) Field of Classification Search ................... 257/98,
`257/82,91,99, 100, 116, 117,432-437,
`257/749, E33.056-E33.059, E25.032
`See application file for complete search history.
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`2003/0020077 A1 *
`112003 Horiuchi eta!. ............... 257/81
`2006/0278882 A1 * 12/2006 Leung et al ................... 257/98
`2008/0035948 A1 * 2/2008 Shin et al ...................... 257/99
`* cited by examiner
`Primary Examiner-Fernando L Toledo
`Assistant Examiner-Mamadou Diallo
`
`(57)
`
`ABSTRACT
`
`A light emitting device is disclosed herein. An embodiment of
`the light emitting device comprises a substrate and a reflector
`extending from the substrate. The reflector forms a cavity in
`conjunction with the substrate. A light emitter is located in the
`cavity. At least one first recessed portion is located in the
`reflector, the at least one first recessed portion extends sub(cid:173)
`stantially axially around the reflector.
`
`17 Claims, 2 Drawing Sheets
`
`Nichia Exhibit 1001
`Page 1
`
`

`

`-....l = N
`
`\C
`'N
`N
`u.
`0..,
`-....l
`rJl
`d
`
`N
`0 .....
`....
`.....
`rFJ =(cid:173)
`
`('D
`('D
`
`0 ....
`~ = N
`
`~
`
`0
`
`N
`~Cl\
`
`128
`
`12 2
`
`110
`
`114
`
`152
`
`I
`
`FIG. 1
`
`160
`
`112
`
`15 4
`
`140
`
`118
`
`~ = ~
`
`~
`~
`~
`•
`00
`~
`
`/100
`
`Nichia Exhibit 1001
`Page 2
`
`

`

`U.S. Patent
`
`Jan.26,2010
`
`Sheet 2 of2
`
`US 7,652,297 B2
`
`100~
`
`134
`
`12 2
`
`110
`
`112
`
`138
`
`114
`
`FIG. 2
`
`Nichia Exhibit 1001
`Page 3
`
`

`

`US 7,652,297 B2
`
`1
`LIGHT EMITTING DEVICE
`
`BACKGROUND
`
`2
`Opposite the upper portion of the outer circumferal wall
`122 is a first inner wall126 that extends toward the substrate
`110 from the upper edge 124. A first platform 128 extends
`from the first inner wall126. A second inner wall13 0 extends
`from the first platform 128.
`The combination of the first inner wall126, the first plat(cid:173)
`form 128 and the second inner wall 130 forms a first notch
`134. The first notch 134 extends axially around the reflector
`114. As described in greater detail below, the first notch 134
`serves to hold the encapsulant within the cavity 118. In addi(cid:173)
`tion, the first notch 134 limits the extent of delamination that
`may occur should delamination start.
`A second platform 138 extends from the second inner wall
`130. A slanted wall 140 extends from the second platform
`15 138. In the embodiment of the light-emitting device described
`herein, the slanted wall 140 is at an angle relative to the
`substrate 110 so that light emitted from the light-emitting
`device 100 has a specified beam pattern associated therewith.
`A second notch 146 is located between the slanted wall140
`20 and a third platform 148. The second notch 146 may extend
`along and around the reflector 114 as shown in FIG. 2. As with
`other portions of the cavity 118, the second notch 146 may be
`filled with the encapsulant. As described in greater detail
`below, the second notch 146 serves to stop delamination
`25 between the reflector 114 and the encapsulant. In the embodi(cid:173)
`ment described herein, the third platform 148 is located pro xi(cid:173)
`mate the substrate 110.
`The reflector 114 has been described above as having well
`defined walls and platforms. In some embodiments, the tran-
`30 sitions between the walls and platforms are relatively smooth,
`so there are few, if any, edges between the transitions.
`In the embodiment of the light-emitting device 100
`described herein, a gap 152 exists between the reflector 114
`and the LED 112. The gap 152 may contain contacts used to
`35 supply power to the LED 112. For illustration purposes, a
`single wire bond 154 is shown extending between the gap 152
`and the LED 112. The wire bond 154 may supply power or
`electrical signals to the LED 112. Other embodiments of the
`light emitting device 100 may have more wires connected
`40 between the LED 112 and the substrate 110.
`Conventional light emitting devices do not have either the
`first notch or the second notch. Delamination between the
`reflector and the encapsulant may start near the top of the
`reflector and continue down the reflector toward the substrate.
`Delamination near the top of the light emitting device will
`adversely affect the brightness and beam pattern of the light
`emitting device. Delamination may also commence at the
`junction of the reflector and the substrate. In either situation,
`delamination may spread to the LED and cause the LED to
`separate from the substrate. In other situations, the wire bonds
`between the LED and the substrate may break.
`The reflector 114 described herein serves to prevent
`delamination or stop delamination after it has started. If
`delamination starts proximate the top or upper edge 124 of the
`reflector 114, the delamination may progress down the first
`inner wall126, but it will be stopped by the first notch 134.
`Therefore, the delamination will not be able to proceed down
`the slanted wall140. The first notch 134 also serves to anchor
`the encapsulant to the reflector 114, which further serves to
`60 prevent delamination. The same occurs with the second notch
`146.
`The reflector 114 has been described herein with two
`notches 134 and 146, the first notch 134 and the second notch
`146. Some embodiments of the reflector 114 may have only
`one of the notches 134 and 146. Other embodiments may have
`more notches located therein that serve to further anchor the
`encapsulant and stop delamination.
`
`Light emitting devices typically include a light emitting 5
`diode (LED) located in a cavity. The walls of the cavity may
`be reflective in order to increase the efficiency of the light(cid:173)
`emitting device. The cavity is filled with an encapsulate, such
`as silicone, in order to protect the LED and the reflector.
`Encapsulants tend to delaminate or pull away from the 10
`reflector walls. Once the delamination has started on a small
`section of the wall, the delamination typically continues rap(cid:173)
`idly. The delaminated areas may enable contaminants to enter
`the light-emitting device and either cause failure or a reduc(cid:173)
`tion in the efficience of the light-emitting device. The delami(cid:173)
`nation may also adversely affect the light pattern proximate
`the delaminated wall, which may reduce or diffract the emit(cid:173)
`ted light. Eventually, the delamination may spread to the
`LED, which may cause damage to the LED and failure of the
`light-emitting device.
`
`BRIEF DESCRIPTION OF DRAWINGS
`
`FIG. 1 is a side cut away view of an embodiment of a
`light-emitting device.
`FIG. 2 is a top plan view of the light-emitting device of
`FIG. 1.
`
`DETAILED DESCRIPTION
`
`A side cut away view of an embodiment of a light-emitting
`device 100 is shown in FIG. 1. As described in greater detail
`below, the light-emitting device 100 described herein uses
`devices and methods to reduce the probability that an encap(cid:173)
`sulant used in the light-emitting device 100 will delaminate or
`peel from components within the light-emitting device 100.
`In addition, devices and methods are described herein to
`reduce the probability that components within the light-emit(cid:173)
`ting device 100 become dislodged.
`The light-emitting device 100 includes a substrate 110 on
`which a Light Emitting Diode (LED) 112 and a reflector 114
`are mounted. The LED 112 may be electrically connected to
`the substrate 110. The portion of the reflector 114 located
`proximate the substrate 110 is sometimes referred to as the
`lower portion. It is noted that the LED 112 is used for illus(cid:173)
`tration and that light emitters other than LEDs may be used in 45
`conjunction with the light emitting device 100 described
`herein. The combination of the substrate 110 and the reflector
`114 forms a cavity 118 in which the LED 112 is located. An
`encapsulant, such as silicone, is located in and fills or sub(cid:173)
`stantially fills the cavity 118. As described in greater detail 50
`below, the encapsulant adheres to the reflector 114, the sub(cid:173)
`strate 110, and the LED 112. The encapsulant serves to keep
`contaminants out of the cavity 118.
`With additional reference to FIG. 2, which is a top plan
`view of the light-emitting device 100 of FIG. 1, the reflector 55
`114 has many recessed portions and the like that secure the
`encapsulant. These recessed portions also reduce delamina(cid:173)
`tion and the probability of delamination between the reflector
`114 and the encapsulant. The reflector 114 has an outer cir(cid:173)
`cumferal wall122 that may form the outer wall of the light(cid:173)
`emitting device 100. An upper edge 124 extends around the
`circumference of the reflector 114 and may form the highest
`point of the light-emitting device 100. The portion of the
`reflector 114 proximate the upper edge 124 is sometimes
`referred to as the upper portion. Light emitted from the light- 65
`emitting device exits the opening in the reflector 114located
`proximate the upper portion.
`
`Nichia Exhibit 1001
`Page 4
`
`

`

`US 7,652,297 B2
`
`3
`The reflector 114 described above serves to prevent
`delamination of the encapsulant. In addition, the LED 112
`may be more firmly secured to the substrate 110 to prevent it
`from lifting from the substrate 110. In conventional light
`emitting devices, the LEDs may separate from the substrate if
`delamination occurs adjacent the LEDs. In addition, thermal
`stresses may weaken the bond between the substrate and the
`LED. The light-emitting device 100 described herein serves
`to overcome these problems by more securely fastening the 10
`LED 112 to the substrate 110.
`In order to more securely attach the LED 112 to the sub(cid:173)
`strate 110, the substrate 110 has at least one recessed portion
`for holding an adhesive located under the LED 112. In the
`embodiment described herein, the substrate has two recessed 15
`portions 160 or dimples. The recessed portions 160 serve to
`hold the adhesive used to adhere the LED 112 to the substrate
`110. This extra adhesion serves to prevent the LED 112 from
`becoming dislodged from the substrate 110. Therefore, if 20
`delamination spreads to the LED 112, the LED 112 has a
`lower probability of becoming dislodged from the substrate
`110.
`It is noted that other recessed portions may be included
`under the LED 112. For example, a single ring may be used. 25
`In another example, a single recessed portion may be pro(cid:173)
`vided.
`It is also noted that the light-emitting device 100 may be
`virtually any shape. For example, rather than being substan(cid:173)
`tially round as shown in FIG. 2, the light-emitting device 110
`and the reflector may be shaped as a rectangle, rhombus,
`square, or ellipse.
`
`What is claimed is:
`1. A light emitting device comprising:
`a substrate;
`a reflector extending from said substrate, said reflector
`forming a cavity in conjunction with said substrate;
`a light emitter located in said cavity; and
`at least one first notch located in said reflector, said at least
`one first notch extending substantially axially around
`said reflector, said at least one first notch being formed
`by a first wall and a second wall wherein said first wall
`and said second wall extend substantially perpendicular
`to said substrate.
`2. The light emitting device of claim 1 and further com(cid:173)
`prising an encapsulant located in said cavity, wherein said
`encapsulant is also located in said at least one first notch.
`3. The light emitting device of claim 1, wherein said reflec(cid:173)
`tor has an upper portion and a lower portion, said lower
`portion being located proximate said substrate, said at least
`one first notch being located proximate said upper portion.
`4. The light emitting device of claim 1, wherein said reflec(cid:173)
`tor has an upper portion and a lower portion, said lower
`portion being located proximate said substrate, said at least
`one first notch being located proximate said lower portion.
`5. The light emitting device of claim 1, wherein said light
`emitter is electrically connected to said substrate.
`6. The light emitting device of claim 1, wherein said reflec(cid:173)
`tor comprises a slanted portion that intersects a platform,
`wherein said platform is located proximate said substrate; and 65
`wherein said at least one notch is located at the intersection of
`said slanted portion and said platform.
`
`4
`7. The light emitting device of claim 1, wherein said sub(cid:173)
`strate comprises at least one recessed portion and wherein
`said light emitter is located on said at least one recessed
`portion.
`8. The light emitting device of claim 7 and further com(cid:173)
`prising an adhesive located in said at least one recessed por(cid:173)
`tion, said adhesive serving to bond said light emitter to said
`substrate.
`9. The light emitting device of claim 1, wherein said reflec(cid:173)
`tor comprises:
`a first wall extending substantially perpendicular to said
`substrate;
`a first platform extending from said first wall;
`a second wall extending from said first platform and facing
`said first wall, the space between said first wall and said
`second wall constituting one of said at least one notch;
`a second platform extending from said second wall toward
`the center of said light emitting device;
`a slanted portion extending from said second platform
`toward said substrate; and
`a third platform located on said substrate and intersecting
`said slanted portion;
`wherein a second of said at least one notch is located at the
`intersection of said third platform and said slanted por(cid:173)
`tion.
`10. A light emitting device comprising: a substrate; a
`reflector extending from said substrate, said reflector forming
`30 a cavity in conjunction with said substrate; a light emitter
`located in said cavity; at least one first notch located in said
`reflector, said at least one first notch extending substantially
`axially around said reflector said at least one first notch being
`formed by a first wall and a second wall wherein said first wall
`35 and said second wall are substantially parallel to each other
`wherein said first wall and said second wall extend substan(cid:173)
`tially perpendicular to said substrate; and at least one second
`recessed portion located in said substrate proximate said light
`emitter.
`11. The light emitting device of claim 10 and further com(cid:173)
`prising an adhesive located in said at least one recessed por(cid:173)
`tion, said adhesive serving to bond said light emitter to said
`substrate.
`12. The light emitting device of claim 10 and further com-
`prising an encapsulant located in said cavity, wherein said
`encapsulant is also located in said at least one first notch.
`13. The light emitting device of claim 10, wherein said
`reflector has an upper portion and a lower portion, said lower
`50 portion being located proximate said substrate, said at least
`one first notch being located proximate said upper portion.
`14. The light emitting device of claim 10, wherein said
`reflector has an upper portion and a lower portion, said lower
`portion being located proximate said substrate, said at least
`55 one first notch being located proximate said lower portion.
`15. A light emitting device comprising:
`a substrate;
`a reflector extending from said substrate, said reflector
`forming a cavity in conjunction with said substrate, said
`reflector comprising:
`a first wall extending substantially perpendicular to said
`substrate;
`a first platform extending from said first wall;
`a second wall extending from said first platform and facing
`said first wall, the space between said first wall and said
`second wall constituting a first notch;
`
`60
`
`40
`
`45
`
`Nichia Exhibit 1001
`Page 5
`
`

`

`US 7,652,297 B2
`
`5
`a second platform extending from said second wall toward
`the center of said light emitting device;
`a slanted portion extending from said second platform
`toward said substrate; and
`a third platform located on said substrate and intersecting
`said slanted portion;
`wherein a second notch is located at the intersection of said
`third platform and said slanted portion;
`a light emitter located in said cavity; and
`
`6
`at least one recessed portion located in said substrate pro xi(cid:173)
`mate said light emitter.
`16. The light emitting device of claim 15 and further com(cid:173)
`prising an adhesive located in said at least one recessed por(cid:173)
`tion, said adhesive serving to bond said light emitter to said
`substrate.
`17. The light emitting device of claim 15 and further com(cid:173)
`prising an encapsulant located in said cavity.
`
`* * * * *
`
`Nichia Exhibit 1001
`Page 6
`
`