US007939842B2
`
`(12) United States Patent
`Loh et al.
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 7,939,842 B2
`*May 10, 2011
`
`(54) LIGHT EMITTING DEVICE PACKAGES,
`LIGHT EMITTING DIODE (LED) PACKAGES
`AND RELATED METHODS
`
`(75) Inventors: Ban P. Loh, Durham, NC (US); Peter
`Scott Andrews. Durham, NC (US);
`Nicholas W. Medendorp, Jr., Raleigh,
`NC (US)
`(73) Assignee: Cree, Inc., Durham, NC (US)
`(*) Notice:
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 714 days.
`This patent is Subject to a terminal dis
`claimer.
`
`(21) Appl. No.: 11/895,795
`(22) Filed:
`Aug. 27, 2007
`
`(65)
`
`Prior Publication Data
`US 2008/OO54286 A1
`Mar. 6, 2008
`
`Related U.S. Application Data
`(63) Continuation-in-part of application No. 11/044,779,
`filed on Jan. 27, 2005, now Pat. No. 7,326,583.
`
`(51) Int. Cl.
`(2006.01)
`HOIL 29/267
`(2006.01)
`HOIL 2L/00
`(2006.01)
`F2IV 9/16
`(2006.01)
`HOL 5/48
`(52) U.S. Cl. ................ 257/98: 257/81; 257/82; 257/91;
`257/99; 257/E33.056; 257/E33.058; 257/E33.059;
`438/27; 438/29: 362/84; 362/27; 313/318.11
`(58) Field of Classification Search .................... 257/98,
`257/81, 82, 91, 99,436; 438/26, 27; 362/84,
`362/267; 313/318.11
`See application file for complete search history.
`
`OO
`
`(56)
`
`References Cited
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`(Continued)
`Primary Examiner — David A. Zarneke
`(74) Attorney, Agent, or Firm — Jenkins, Wilson, Taylor &
`Hunt, PA.
`
`ABSTRACT
`(57)
`Light emitting device packages, light emitting diode (LED)
`packages and related methods are disclosed. According to one
`aspect, a light emitting device package is provided. The pack
`age includes a mounting pad adapted for attachment of a light
`emitting device. A lens coupler is attached to the mounting
`pad and defines an opening for containing the light emitting
`device and a quantity of encapsulant. The lens coupler
`includes a surface defining a depression which comprises at
`least one edge that shapes an outer Surface of the encapsulant.
`
`25 Claims, 16 Drawing Sheets
`
`
`
`C2-S-2 " .
`
`
`
`
`
`2
`
`Nichia Exhibit 1004
`Page 1
`
`

`

`US 7,939,842 B2
`Page 2
`
`U.S. PATENT DOCUMENTS
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`7, 2006 LOh
`7.210,807 B2 * 5/2007 Sakamoto et al. .............. 362/84
`7,326,583 B2
`2/2008 Andrews
`2001/003O326 A1 10, 2001 Reeh et al.
`2002/0057056 A1
`5, 2002 Okazaki
`2002fOO79837 A1
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`2002/0123164 Al
`9/2002 Slater, Jr. et al.
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`2003. O141510 A1
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`
`3/2004 Loh
`2004/0041222 A1
`3/2004 Slater, Jr. et al.
`2004/0056260 A1
`7, 2004 Loh
`2004/O126913 A1
`2005/0221518 A1 10, 2005 Andrews
`2006/0186423 A1
`8/2006 Blonder et al.
`2006/0278882 Al 12/2006 Leung et al.
`FOREIGN PATENT DOCUMENTS
`
`9, 2000
`1187226
`EP
`2, 1996
`O8032120
`JP
`1, 1997
`O9027643
`JP
`3, 1998
`10065220
`JP
`7, 1998
`10 190065
`JP
`2, 1999
`2000-252523
`JP
`12, 2004
`3604298
`JP
`7/2005
`2005-197369
`JP
`3, 2001
`WOO1/O15242
`WO
`3, 2001
`WO WO 2004/068594
`10/2005
`WO WO 2005. O98975
`10/2005
`WO WO 2005. O98976
`10/2005
`WO WO 2005, O98977
`OTHER PUBLICATIONS
`International Search Report and Written Opinion for PCT/US2005/
`O09779 dated Feb. 28, 2006.
`International Search Report and Written Opinion for PCT/US2005/
`01.0034 dated Feb. 22, 2006.
`* cited by examiner
`
`Nichia Exhibit 1004
`Page 2
`
`

`

`U.S. Patent
`
`May 10, 2011
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`Sheet 1 of 16
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`US 7,939,842 B2
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`Nichia Exhibit 1004
`Page 3
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`U.S. Patent
`
`May 10, 2011
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`Sheet 2 of 16
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`US 7,939,842 B2
`
`t
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`106
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`Nichia Exhibit 1004
`Page 4
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`U.S. Patent
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`May 10, 2011
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`Sheet 3 of 16
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`US 7,939,842 B2
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`Nichia Exhibit 1004
`Page 5
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`May10, 2011
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`U.S. Patent
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`May 10, 2011
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`Sheet 5 of 16
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`US 7,939,842 B2
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`Nichia Exhibit 1004
`Page 7
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`U.S. Patent
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`May 10, 2011
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`May 10, 2011
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`Sheet 7 of 16
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`Nichia Exhibit 1004
`Page 9
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`U.S. Patent
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`May 10, 2011
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`Sheet 8 of 16
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`US 7,939,842 B2
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`Nichia Exhibit 1004
`Page 10
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`May 10, 2011
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`US 7,939,842 B2
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`Nichia Exhibit 1004
`Page 11
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`U.S. Patent
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`May 10, 2011
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`May10, 2011
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`May10, 2011
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`May 10, 2011
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`May 10, 2011
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`

`

`US 7,939,842 B2
`
`1.
`LIGHT EMITTING DEVICE PACKAGES,
`LIGHT EMITTING DIODE (LED) PACKAGES
`AND RELATED METHODS
`
`2
`Accordingly, there exists a need for light emitting device
`packages, LED packages and related methods that provide
`improvements in the quality of emitted light.
`
`RELATED APPLICATIONS
`
`SUMMARY
`
`This application is a continuation-in-part application of
`U.S. patent application Ser. No. 11/044,779, titled “Reflector
`Packages and Methods for Packaging of a Semiconductor
`Light Emitting Device” and filed Jan. 27, 2005 now U.S. Pat.
`No. 7,326,583; the disclosure of which is incorporated herein
`by reference in its entirety.
`
`TECHNICAL FIELD
`
`10
`
`15
`
`The subject matter described herein relates to semiconduc
`tor device packages. More particularly, the Subject matter
`described herein relates to light emitting device packages,
`light emitting diode packages and related methods.
`
`BACKGROUND
`
`25
`
`30
`
`35
`
`40
`
`Semiconductor light emitting devices, such as a light emit
`ting diode (LED), may be provided in a package for protec
`tion, color selection, focusing, and the like for light emitted
`by the device. An LED package generally includes a Substrate
`member on which an LED is mounted. The LED may include
`a mounting pad attached to the Substrate member with elec
`trical connections being made to the LED for applying an
`electrical bias. LEDs generally comprise an active region of
`semiconductor material sandwiched between two oppositely
`doped layers. When a bias is applied across the doped layers,
`holes and electrons are injected into the active region where
`they recombine to generate light. Light is emitted omnidirec
`tionally from the active layer and from all surfaces of the
`LED. The substrate member may also include traces or metal
`leads for connecting the package to external circuitry and the
`Substrate may also act as a heat sink to conduct heat away
`from the LED during operation.
`An LED package may include a lens positioned for receiv
`ing light emitted by an LED in the package. The lens may
`include optical materials intended to influence or change the
`nature of the light emitted by the LED. Further, the lens may
`be suitably shaped for scattering the light and/or otherwise
`45
`redirecting or influencing the light.
`A lens is typically attached to the LED package by use of
`encapsulant. For example, an LED may be positioned within
`an opening formed by the LED package. The opening may be
`filled with encapsulant, and the lens attached to the top of the
`encapsulantatan open end of the opening. Light generated by
`the LED may pass through the encapsulant for receipt by the
`LED.
`LED packages are intended to operate in a wide range of
`environments. Typically, LED packages are expected to oper
`ate over a wide range of varying temperatures. One difficulty
`in current LED packages is that Voids form in encapsulant
`used to attach a lens when operated in varying temperatures.
`The formation of Voids can cause Substantial degradation in
`the quality of light emitted by the LED package. In particular,
`the Void can cause the light passing through the encapsulant to
`appear non-uniform when emitted from the package. It is
`desirable to provide improvements in LED packages and
`techniques used for attaching a lens to an LED package.
`Particularly, it would be beneficial to provide techniques for
`minimizing or preventing the formation of Voids in encapsu
`lant.
`
`50
`
`55
`
`60
`
`65
`
`According to one aspect, the Subject matter described
`herein includes light emitting device packages, light emitting
`diode packages and related methods. According to one
`aspect, a light emitting device packages includes a mounting
`pad adapted for attachment of a light emitting device. The
`package also includes a lens coupler attached to the mounting
`pad. The lens coupler defines an opening for containing the
`light emitting device and a quantity of encapsulant. Further,
`the lens coupler includes a Surface defining a depression
`which comprises at least one edge that shapes an outer Surface
`of the encapsulant.
`According to another aspect, a method of forming a light
`emitting device package includes providing a mounting pad
`adapted for attachment of a light emitting device. Further, a
`lens coupler is attached to the mounting pad. The lens coupler
`defines an opening for containing the light emitting device.
`Further, the lens coupler includes a Surface defining a depres
`sion which comprises at least one edge. An encapsulant is
`deposited in the opening Such that the at least one edge of the
`Surface shapes an outer Surface of the encapsulant. Further, a
`lens is positioned to Substantially enclose the opening and to
`interface with the convex meniscus of the encapsulant.
`According to another aspect, an LED package includes a
`Substrate including a mounting pad. An LED is attached to the
`mounting pad. Further, a lens coupler is attached to the
`mounting pad. The lens coupler defines an opening for con
`taining the LED and a first quantity of encapsulant. The lens
`coupler includes at least one surface defining a first depres
`sion which comprises a first edge that shapes the first quantity
`ofencapsulant. Further, the Surface defines second depression
`which comprises a second edge that Substantially Surrounds
`the first edge and shapes an outer Surface of a second quantity
`of encapsulant. A lens is positioned to Substantially enclose
`the opening and to interface with the first and second encap
`Sulants.
`According to yet another aspect, a method of forming an
`LED package includes providing a substrate including a
`mounting pad. Further, the method includes attaching an LED
`to the mounting pad. A lens coupler is attached to the mount
`ing pad. The lens coupler defines an opening for containing
`the LED. Further, the lens coupler includes at least one sur
`face defining a first depression which comprises a first edge.
`The Surface also defines a second depression which com
`prises a second edge that Substantially Surrounds the first
`edge. A first quantity of encapsulant is deposited in the open
`ing Such that the first edge of the Surface shapes an outer
`Surface of the first quantity of encapsulant. Further, a second
`quantity of encapsulant is deposited on the first quantity of
`encapsulant such that the second edge of the Surface shapes an
`outer Surface of the second quantity of encapsulant. A lens is
`positioned to Substantially enclose the opening and to inter
`face with the second quantity of encapsulant.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`Preferred embodiments of the subject matter described
`herein will now be explained with reference to the accompa
`nying drawings of which:
`FIG. 1 is a top perspective view of a light emitting device
`package according to an embodiment of the Subject matter
`described herein;
`
`Nichia Exhibit 1004
`Page 19
`
`

`

`US 7,939,842 B2
`
`3
`FIG. 2 is a top plan view of the light emitting device
`package shown in FIG. 1;
`FIG. 3 is a side plan view of the light emitting device
`package shown in FIGS. 2 and 3;
`FIG. 4A is a cross-sectional side view of the light emitting
`device package shown in FIGS. 1-3:
`FIG. 4B is a cross-sectional side view of an assembly step
`of the light emitting device package shown in FIG. 4A;
`FIG. 4C is a cross-sectional side view of another assembly
`step of the light emitting device package shown in FIG. 4A;
`FIG. 5 is a top plan view of a substrate, a lens coupler, and
`a light emitting device assembly according to an embodiment
`of the subject matter described herein;
`FIG. 6 is an exploded perspective view of a light emitting
`device package according to an embodiment of the Subject
`matter described herein;
`FIG. 7 is a bottom plan view of a substrate according to an
`embodiment of the subject matter described herein; and
`FIGS. 8A-8G are cross-sectional side view of a light emit
`ting device package showing alternative embodiments of a
`lens coupler.
`
`10
`
`15
`
`4
`Further, in accordance with another aspect of the subject
`matter disclosed herein, an LED package is provided. The
`package includes a Substrate including a mounting pad. An
`LED may be attached to the mounting pad. A lens coupler
`may be attached to the mounting pad and define an opening
`for containing the LED and a first quantity of encapsulant.
`The lens coupler includes at least one Surface defining a first
`depression which comprises a first edge that Substantially
`Surrounds an open end of the opening and that shapes the first
`quantity of encapsulant into a first convex meniscus. The
`Surface defines a second depression which comprises a sec
`ond edge that Substantially Surrounds the first edge and
`shapes a second quantity of encapsulant into a second convex
`meniscus. Further, a lens may be positioned to Substantially
`enclose the opening and to interface with the convex menis
`cus of the encapsulant.
`As used herein, the term “light emitting device' may
`include an LED, laser diode, and/or other semiconductor
`device which includes one or more semiconductor layers,
`which may include silicon, silicon carbide, gallium nitride
`and/or other semiconductor materials, a Substrate which may
`include Sapphire, silicon, silicon carbide and/or other micro
`electronic Substrates, and one or more contact layers which
`may include metal and/or other conductive layers. The design
`and fabrication of semiconductor light emitting devices is
`well known to those having skill in the art and need not be
`described in detail herein. For example, the semiconductor
`light emitting device may be gallium nitride-based LEDs or
`lasers fabricated on a silicon carbide Substrate Such as those
`devices manufactured and sold by Cree, Inc. of Durham,
`N.C., although other emitting devices from other material
`systems may also be used.
`As used herein, the term “encapsulant may include any
`Suitable transparent or semitransparent material for adhering
`objects together. For example, an encapsulant can be a liquid
`silicone gel or epoxy-based material. Further, the encapsulant
`may contain one or more of oxide particles, silicates, nano
`particles, light scattering particles, light diffusing particles,
`color filtering material, and phosphors of the same or differ
`ent type.
`FIGS. 1, 2 and 3 area top perspective view, a top plan view,
`and a side plan view, respectively, of a light emitting device
`package, generally designated 100, according to an embodi
`ment of the subject matter described herein. Referring to
`FIGS. 1-3, package 100 includes a substrate 102, a lens 104,
`and a lens coupler 106. Lens coupler 106 can be adapted for
`attachment to substrate 102 and for placement of lens 104 in
`an operable position with respect to a light emitting device,
`which is attached to substrate 102. The operable position can
`include positions at which light emitted by a light emitting
`device attached to substrate 102 can transmit through lens
`104. Particularly, lens coupler 106 can be structured, as
`described in more detail hereinbelow, to align a center of lens
`104 along a vertical axis with the light emitting device.
`Lens 104 may be made from material having high light
`transmissivity Such as, for example only, glass, quartz, high
`temperature and transparent plastic, or a combination of these
`materials. The lens may define a recess in the bottom thereof
`having a curved, hemispherical, or other geometry, which can
`be filled with optical materials intended to influence or
`change the nature of the light emitted by a light emitting
`device in package 100. Examples of one type of optical mate
`rial are luminescence converting phosphors, dyes, fluorescent
`polymers or other materials which absorb some of the light
`emitted by the light emitting device and re-emit light of
`different wavelengths. Examples of another type of optical
`material are light diffusants such as calcium carbonate, scat
`
`DETAILED DESCRIPTION
`
`30
`
`35
`
`40
`
`25
`
`Light emitting device packages, LED packages and related
`methods are described herein with reference to FIGS. 1-8G,
`which illustrate various embodiments. As illustrated in the
`Figures, some sizes of structures or portions may be exagger
`ated relative to other structures or portions for illustrative
`purposes and, thus, are provided to illustrate the general struc
`tures of the subject matter disclosed herein. Further, various
`aspects of the subject matter disclosed herein are described
`with reference to a structure or a portion being formed on
`other structures, portions, or both. As will be appreciated by
`those of skill in the art, references to a structure being formed
`“on” or “above' another structure or portions contemplates
`that additional structure, portion, or both may intervene. Ref
`erences to a structure or a portion being formed “on” another
`structure or portion without an intervening structure or por
`tion are described herein as being formed “directly on the
`structure or portion.
`Furthermore, relative terms such as “on” or "above' are
`used herein to describe one structure's or portion’s relation
`ship to another structure or portion as illustrated in the Fig
`ures. It will be understood that relative terms such as “on” or
`45
`“above' are intended to encompass different orientations of
`the device in addition to the orientation depicted in the Fig
`ures. For example, if the device in the Figures is turned over,
`structure or portion described as “above other structures or
`portions would now be oriented “below the other structures
`or portions. Likewise, if the device in the Figures is rotated
`along an axis, structure orportion described as "above other
`structures orportions would now be oriented “next to” or “left
`of the other structures orportions. Like numbers refer to like
`elements throughout.
`According to one aspect of the Subject matter disclosed
`herein, a light emitting device package is provided. The pack
`age includes a mounting pad adapted for attachment of a light
`emitting device. A lens coupler is attached to the mounting
`pad and defines an opening for containing the light emitting
`device and a quantity of at least partially cured encapsulant.
`The lens coupler includes a Surface defining a depression
`which comprises at least one edge that Substantially Sur
`rounds an open end of the opening and that shapes the encap
`Sulant into a convex meniscus. The package may include a
`lens positioned to Substantially enclose the opening and to
`interface with the convex meniscus of the encapsulant.
`
`50
`
`55
`
`60
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`65
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`Nichia Exhibit 1004
`Page 20
`
`

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`US 7,939,842 B2
`
`5
`tering particles (such as titanium oxides) or Voids which
`disperse or scatter light. Any single or combination of the
`above materials can be applied on the lens to obtain certain
`spectral luminous performance.
`Substrate 102 may be formed of many different materials,
`including electrically insulating materials. Suitable Substrate
`materials include, but are not limited to, ceramic materials
`Such as aluminum nitride (AIN) and alumina (Al2O).
`Dimensions of substrate 102 can vary widely depending on
`application and processes used to manufacture package 100.
`For example, in the illustrated embodiment, substrate 102
`may have dimensions ranging from fractions of millimeters
`(mm) to tens of millimeters.
`Lens coupler 106 may be disk-shaped or any other suitable
`shape and formed of a durable, high melting temperature
`material that can withstand Subsequent packaging manufac
`turing steps and the heat generated by the package during
`operation. Many different materials can be used, including
`plastics, such as a Novella resin, or liquid crystal polymers.
`Lens coupler 106 may be made of a material that reflects
`and/or scatters light.
`FIG. 4A is a cross-sectional side view of package 100
`shown in FIGS. 1-3. Referring to FIG. 4A, a semiconductor
`light emitting device assembly, generally designated 108, is
`mounted on a mounting pad 109 attached to the top of sub
`strate 102. Assembly 108 can include an LED 110, which may
`be mounted to a mounting pad 109. Mounting pad 109 may be
`mounted to substrate 102 with electrical connections being
`made to LED 110 for applying an electrical bias. A top surface
`of LED 110 may be connected to electrical connections via
`one or more conductive bond wires 112.
`Lens coupler 106 can include reflective surfaces positioned
`to reflect light generated by LED 110. Particularly, the reflec
`tive surfaces can be positioned for directing the light
`upwardly and away from package 100 so that it can contribute
`to useful light emission of package 100. Further, lens coupler
`106 can have many different shapes and sizes and to enhance
`its reflectivity, may include a reflective element covering
`different portions of the coupler surface around LED 110.
`Alternatively, lens coupler 106 can be made of a reflective
`material such that light from LED 110 directed toward the
`surfaces of coupler 106 is reflected to contribute to package
`emission.
`Lens 104 may be attached to substrate 102 and lens coupler
`106 by use of an encapsulant 111. In particular, encapsulant
`111 may be deposited in a space 400 defined between sub
`strate 102, lens 104, and/or lens coupler 106. Encapsulant 111
`may be any Suitable type of resin material Such as a silicone or
`epoxy-based material. The Volume of encapsulant 111 may
`be kept at a minimum such that assembly 108 is positioned
`within space 400 and such that lens 104 is securely attached to
`substrate 102. Further, the distance of the spacing between
`substrate 102 and lens 104 may be kept at a minimum such
`that the vertical movement of lens 104 is at a minimum over
`the operating temperature ranges of package 100. In one
`example, if the distance between substrate 102 and lens 104 is
`about 100 um, lens 104 only moves up by a few microns at a
`high operating temperature. Further, the distance between
`substrate 102 and lens 104 can be less than about 100 um.
`Lens 104 can be placed on top of and adhere to encapsulant
`111. Lens 104 is not rigidly bonded to lens coupler 106. This
`“floating lens' design will ensure that encapsulant 111 can
`expand and contract under high and low temperature condi
`tions without problem. For instance, when package 100 is
`operating or being Subjected to a high temperature environ
`ment, encapsulant 111 experiences greater Volumetric expan
`sion than the cavity space that contains it. By allowing lens
`
`40
`
`45
`
`6
`104 to float somewhat freely on top of encapsulant 104, no
`encapsulant will be squeezed out of its cavity space. Like
`wise, when package is subjected to cold temperature, encap
`sulant 111 will contract more than the other components that
`make up the cavity space for encapsulant 111. Lens 104 will
`float freely on top of encapsulant 111 as the latter shrinks and
`its level drops. Hence, the reliability of package 100 is main
`tained over a relatively large temperature range as the thermal
`stresses induced on its encapsulant 111 is reduced by the
`floating lens design.
`During assembly of package 100, lens coupler 106 is
`bonded to substrate 102. Subsequently, lens 104 is attached to
`lens coupler 106 and substrate 102 by use of encapsulant 111.
`Initially, a first quantity of encapsulant is deposited within an
`opening defined by the attachment of lens coupler 106 to
`mounting pad 109. FIG. 4B is a cross-sectional side view of
`package 100 at an assembly step when a first quantity of
`encapsulant 111A is deposited within an opening, generally
`designated 402, defined by the attachment of lens coupler 106
`to mounting pad 109. Referring to FIG. 4B, encapsulant 111A
`is deposited in an opening 402. Opening 402 can include an
`open end into which encapsulant 111A is deposited. The open
`end of opening 402 is defined by ledge surface 404 of lens
`coupler 106, which surrounds the open end of opening 402.
`Lens coupler 106 includes a ledge surface 404 that sub
`stantially surrounds the open end of opening 402. Ledge
`surface 404 defines first and second depressions 406 and 408,
`which substantially surround the open end. Depressions 406
`and 408 include edges 410 formed at an interface of surface
`404 and the depressions. Opening 402 is filled with encapsu
`lant 111A until the encapsulant 111A forms a convex menis
`cus, which is formed by an edge of depression 406. Depres
`sion 406 can entirely or at least substantially surround the
`open end of opening 402 (see also FIGS. 5 and 6). Further,
`edges 410 of depression 406 can entirely or at least substan
`tially Surround the open end of opening 402. Subsequent to
`forming the convex meniscus, encapsulant 111A can be par
`tially or fully cured. For example, the encapsulant may be
`cured to about 50%.
`Depressions 406 and 408 can have any suitable size and
`shape for forming an outer Surface of encapsulant 111A. For
`example, the depression can have Substantially vertical walls
`Such that a convex meniscus is formed by encapsulant 111A
`when opening 402 is filled with encapsulant 111A. In one
`example, a vertical wall of depressions 406 and 408 can be
`about 90° with respect to ledge surface 404. Further, a wall of
`depressions 406 and 408 can be inclined in the range of
`between about 60° and about 90° with respect to ledge surface
`404. The width and depth of depressions 406 and 408 can
`range between 5 and 10 mils, although the depressions may
`have any other suitable depth or width.
`FIG. 4C is a cross-sectional side view of package 100 at an
`assembly step when a second quantity of encapsulant 111B is
`deposited within opening 402. Referring to FIG. 4C, encap
`sulant 111B can be deposited directly on encapsulant 111A.
`In particular, encapsulant 111B can cover encapsulant 111B
`and form a convex meniscus. The convex meniscus of encap
`sulant 111B can be formed by one of the edges of depression
`408. Depression 408 can entirely or at least substantially
`surround the open end of opening 402 (see also FIGS. 5 and
`6). Further, edges 410 of depression 408 can entirely or at
`least Substantially surround the open end of opening 402.
`Encapsulant 111B may be uncured or partially cured. Encap
`sulant 111B can be deposited in an amount such that the
`encapsulant does not overflow guide Surfaces 407 of opening
`402 when a lens is positioned on top of the encapsulant.
`Surfaces 404 and 407 may be reflective for reflecting light
`
`10
`
`15
`
`25
`
`30
`
`35
`
`50
`
`55
`
`60
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`65
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`Nichia Exhibit 1004
`Page 21
`
`

`

`7
`generated by LED 110 in a substantially upward direction.
`Alternatively, surfaces 404 and 407 may be non-reflective.
`Together, encapsulant 111A and 111B can form encapsu
`lant 111 shown in FIG. 4A. Encapsulant 111A is substantially
`or entirely cured such that it remains in a form with a convex
`meniscus even after placement of lens 104. Lens 104 includes
`a concave surface 113 in the bottom thereofthat substantially
`conforms to a Surface of the convex meniscus of encapsulant
`111A. Encapsulant 111B is left uncured or only partially
`cured such that lens 104 “rests’ or “floats’ on encapsulant
`111B after placement. As shown in FIG. 4A, encapsulant
`111B spreads laterally and over ledge surface 404 after place
`ment of lens 104.
`In an alternative embodiment, lens 104 may include a flat
`surface 115 (shown to be coplanar with the top surface of
`encapsulant 111B) that is positioned to face the encapsulant
`and LED 110. Lens 104 is substantially hemispherical in
`shape, and the flat surface of lens 104 is facing the encapsu
`lant and LED 110. Further, in this embodiment, at least a
`portion of the top surface of encapsulant 111A may substan
`tially conform to flat surface 115. As a result, the top surface
`of encapsulant 111A is lower than the position indicated by
`reference numeral 111A and at the position indicated by
`reference numeral 111C.
`The forming separate forming of encapsulant portions
`111A and 111B as described herein serves to minimize or
`prevent the formation of voids within encapsulant 111. Par
`ticularly, the formation of voids is minimized or prevented by
`placement of lens 104 onto encapsulant portions 111A and
`111B. A bottom surface of lens 104 is positioned to interface
`with the top surface of encapsulant 111A. As lens 104 is
`positioned onto encapsulant 111A, encapsulant 111B is
`forced from between lens 104 and encapsulant 111A to rest
`on top of ledge Surface 404 along the outer edge of encapsu
`lant 111A. The outside edge of lens 104 interfaces with
`encapsulant 111B. Because encapsulant 111B is forced from
`between lens 104 and encapsulant 111A, bubble formation is
`minimized or prevented in the areas where light passes
`through encapsulant 111. As a result of reduced bubbles in
`these areas, the quality of light produced by light emitting
`device package 100 is improved.
`Lens coupler 106 may be adapted to precisely align lens
`104 with LED 110 during assembly. Lens coupler 106 may
`include one or more top surfaces that are shaped to Substan
`tially fit to a bottom portion of lens 104 and function as a guide
`for aligning lens 104 into its operational position with respect
`to LED 110. Particularly, ledge surface 404 may substantially
`fit to an outside edge of a bottom surface of lens 104. When
`lens 104 is fitted to lens coupler 106 in this way, LED 110 is
`substantially aligned with lens 104. Further, lens coupler 106
`may include one or more guide surfaces 407 adapted for
`guiding the movement of lens 104 into its operational position
`during assembly. Guide surface 407 can be substantially fun
`nel shaped for precisely positioning the outside edge of bot
`tom Surface 404 against ledge Surface 404.
`FIG. 5 is a top plan view of substrate 102, lens coupler 106,
`and light emitting device assembly 108. Referring to FIG.