(12) United States Patent
`Wojnarowski et al.
`
`I lllll llllllll Ill lllll lllll lllll lllll lllll 111111111111111111111111111111111
`US006412971Bl
`US 6,412,971 Bl
`Jul. 2, 2002
`
`(10) Patent No.:
`(45) Date of Patent:
`
`(54) LIGHT SOURCE INCLUDING AN ARRAY OF
`LIGHT EMITTING SEMICONDUCTOR
`DEVICES AND CONTROL METHOD
`
`(75)
`
`Inventors: Robert John Wojnarowski, Ballston
`Lake; Barry Scott Whitmore,
`Waterford; William Paul Kornrumpf,
`Albany, all of NY (US)
`
`(73) Assignee: General Electric Company,
`Schenectady, NY (US)
`
`( *) Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 0 days.
`
`(21) Appl. No.: 09/258,935
`
`(22) Filed:
`
`Mar. 1, 1999
`
`Related U.S. Application Data
`
`( 60) Continuation-in-part of application No. 09/217,334, filed on
`Dec. 21, 1998, now Pat. No. 6,002,163, which is a division
`of application No. 09/002,314, filed on Jan. 2, 1998, now
`Pat. No. 5,888,884.
`Int. Cl.7 ................................................ HOlL 33/00
`(51)
`(52) U.S. Cl. ....................... 362/249; 362/252; 362/800;
`313/500; 257/88
`(58) Field of Search ................................. 362/249, 252,
`362/800, 247; 257/88, 13, 81, 93; 313/500
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
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`4,835,704 A
`4,845,405 A *
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`4,984,358 A
`
`2/1973 Anderson ................... 313/500
`5/1989 Eichelberger et al.
`...... 364/490
`7/1989 Yamane et al. ............. 313/500
`6/1990 Nelson ........................ 29/854
`6/1990 Sagawa et al.
`............. 313/500
`1/1991 Nelson ........................ 29/830
`
`4,999,755 A * 3/1991 Lin ............................ 362/800
`5,162,878 A * 11/1992 Sasagawa et al.
`.......... 362/800
`5,300,788 A * 4/1994 Fan et al.
`..................... 257/13
`10/1994 Fillion et al. ................. 29/840
`5,353,498 A
`5,404,282 A * 4/1995 Klinke et al. ............... 362/800
`5,492,586 A
`2/1996 Gorczyca .................... 156/245
`5,497,033 A
`3/1996 Fillion et al. ............... 257/723
`5,504,514 A * 4/1996 Nelson ....................... 362/800
`5,527,741 A
`6/1996 Cole et al. .................. 437/209
`5,567,657 A
`10/1996 Wojnarowski et al. ...... 437/214
`5,679,977 A * 10/1997 Khandros et al. ........... 257/902
`5,793,062 A * 8/1998 Kish, Jr. et al.
`............ 362/800
`5,857,767 A * 1/1999 Hochstein ................... 362/800
`1/2000 Mueller et al.
`6,016,038 A
`6,038,005 A * 3/2000 Handschy ................... 362/800
`
`OTHER PUBLICATIONS
`
`Overton's Trailer Light Brochure, 111 Red Banks Road, PO
`Box 8228, Greenville, NC 27835.
`Wojnarowski, allowed U.S. Application No. 09/002, 314,
`filed Jan. 2, 1998.
`Srivastava et al., U.S. Application No. 09/203,212, filed
`Nov. 30, 1998.
`* cited by examiner
`Primary Examiner-Thomas M. Sember
`(74) Attorney, Agent, or Firm-Ann M. Agosti; Jill M.
`Breedlove
`
`(57)
`
`ABSTRACT
`
`A light source includes a substrate; an array of un-packaged
`light emitting semiconductor devices (LESDs), each of the
`LESDs having at least one surface for emitting light and a
`substrate surface being attached to the substrate; and a
`plurality of electrical connections, each electrical connection
`coupled for providing electrical power to a respective LESD.
`The LESDs are arranged on the substrate with sufficient
`density and light generating capability to provide a prede(cid:173)
`termined irradiation from the light source.
`
`24 Claims, 16 Drawing Sheets
`
`22 r
`
`23
`
`52
`
`23
`
`21
`
`20
`
`21
`
`IPR PAGE 1
`
`Acuity v. Lynk
`Acuity Ex.
`
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`U.S. Patent
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`Jul. 2, 2002
`
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`IPR PAGE 4
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`

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`U.S. Patent
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`Jul. 2, 2002
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`IPR PAGE 5
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`IPR PAGE 8
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`U.S. Patent
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`Jul. 2, 2002
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`IPR PAGE 9
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`Jul. 2, 2002
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`IPR PAGE 10
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`

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`US 6,412,971 Bl
`
`1
`LIGHT SOURCE INCLUDING AN ARRAY OF
`LIGHT EMITTING SEMICONDUCTOR
`DEVICES AND CONTROL METHOD
`
`This Application is a Continuation-In-Part of Ser. No.
`09/217,334 filed Dec. 21, 1998 now U.S. Pat. No. 6,002,163,
`which is a division of Ser. No. 09/002,314 filed Jan. 2, 1998
`now U.S. Pat. No. 5,888,884. This application claims pri(cid:173)
`ority from U.S. Pat. Nos. 6,002,163 and 5,888,884.
`
`BACKGROUND
`
`The present invention relates generally to light sources.
`Conventional incandescent light bulbs have limited light
`efficiency. Conventional florescent light bulbs include mer(cid:173)
`cury. Pre-packaged light emitting devices have been used in
`trailer lights commercially available from Overton's
`(Greenville, N.C.), for example, but the LED packaging
`presents density problems. There is a need for a light source
`that has long life and high efficiency and that does not create
`environmental concerns.
`
`BRIEF SUMMARY OF THE INVENTION
`
`5
`
`15
`
`2
`DETAILED DESCRIPTION OF THE
`INVENTION
`In FIGS. 1 and 2, one embodiment of the present inven(cid:173)
`tion is embodied in side and top views of a light source 10.
`In FIGS. 1 and 2 light source 10 includes a substrate 16 and
`an array 12 of unpackaged light emitting semiconductor
`devices (LESDs) 14. Each of the LESDs has at least one
`light emitting surface 13 and/or 17 for emitting light and a
`substrate surface 15 attached to the substrate. Each of a
`10 plurality of electrical connections 24 is coupled for provid(cid:173)
`ing electrical power to a respective LESD, and the LESDs
`are arranged on the substrate with sufficient density and light
`generating capability to provide a predetermined or selected
`irradiation from the light source.
`Substrate 16 may comprise any suitable structural mate-
`rial such as a ceramic, a molded plastic material, a flexible
`interconnect structure, or a printed circuit board, for
`example. The substrate may comprise a fiat substrate as
`shown in FIG. 1. As discussed further below, if desired, the
`20 substrate may comprise a curved, conformal, or flexible
`substrate. Substrate 16 may comprise or include a multilayer
`interconnect structure 18. More details on an embodiment
`for multilayer structure 18 are provided below with respect
`to FIG. 6.
`LESDs 14 may comprise light emitting devices such as
`light emitting diodes (LEDs) or laser diodes, for example.
`Conventional LESDs can be used as well as new types of
`light emitting devices as such new types of light emitting
`devices are developed. The term "un-packaged" is meant to
`describe LESDs that are derived from the wafer state and
`may have some electrical connections 24 patterned thereon
`as described below with respect to FIGS. 3-7, for example.
`The un-packaged LESDs may either (a) each have a respec-
`35 tive individual wafer or (b) be situated such that a single
`wafer includes multiple LESDs.
`In the past, light colors for LEDs, in particular, were
`typically red, blue, yellow, or green. Recently, white LEDs
`have become commercially available. A useful light emitting
`40 device with a phosphor composition for providing white
`light is disclosed, for example, in commonly assigned
`Srivastava et al., U.S. application Ser. No. 09/203,212, filed
`Nov. 30, 1998. LESDs can be attached to the substrate by
`any of a number of techniques including, for example,
`45 adhesive (not shown) or solder (shown in FIG. 6).
`LESDs are typically small in active light area. For
`example, active areas typically range from about 50
`micrometers to about 100 micrometers. A number of LESDs
`(which varies according to the light source design and the
`50 desired light output) are positioned to produce a useful light
`output consistent with conventional light bulb technologies.
`As technology progresses and LESDs increase in light
`output capabilities, a smaller number of LESDs than at
`present will be needed to produce a comparable light power
`density.
`Array 12 may comprise one or more arrays, shown in FIG.
`2 as arrays 12 and 112, for example, which can be situated
`on a common substrate or situated in sub-modules on
`separate substrates. Applications for such arrays include, but
`60 are not limited to: ceiling lighting, back-lit liquid crystal
`display lap top computers, locomotive displays, photoresist
`exposure systems, television screens, wall sized light, pho(cid:173)
`tographic display arrays, as well as focused light sources
`such as head lights and flash lights, for example.
`Electrical connections 24, shown in FIG. 2 as extending
`on side surface 17 of each LESD, are for purposes of
`example only. Wire bond connections 68 such as shown in
`
`Briefly, according to one embodiment of the invention, a
`light source includes a substrate; an array of un-packaged
`light emitting semiconductor devices (LESDs , each of the
`)
`LESDs having at least one surface for emitting light and a
`substrate surface being attached to the substrate; and a
`plurality of electrical connections, each electrical connection
`coupled for providing electrical power to a respective LESD.
`The LESDs are arranged on the substrate with sufficient 30
`density and light generating capability to provide a prede(cid:173)
`termined irradiation from the light source.
`
`25
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`The features of the invention believed to be novel are set
`forth with particularity in the appended claims. The inven(cid:173)
`tion itself, however, both as to organization and method of
`operation, together with further objects and advantages
`thereof, may best be understood by reference to the follow(cid:173)
`ing description taken in conjunction with the accompanying
`drawings, where like numerals represent like components, in
`which:
`FIGS. 1 and 2 are side and top views of one embodiment
`of a of a light source of the present invention.
`FIGS. 3 and 4 are top and bottom views of different
`embodiments of light emitting semiconductor devices
`(LESDs) for use in the embodiments of FIGS. 1 and 2.
`FIGS. 5-7 are side views of different embodiments of
`LESDs for use in the embodiments of FIGS. 1 and 2.
`FIGS. 8 and 9 are side views showing embodiments of the
`present invention wherein a flexible or curved substrate is
`included.
`FIGS. 10-13 are side views of different embodiments of
`reradiative components for use with the present invention. 55
`FIGS. 14--20 are views of different embodiments of
`reflector components for use with the present invention.
`FIG. 21 is a view of one embodiment of the present
`invention wherein the light source is in the shape of a
`conventional incandescent light bulb.
`FIGS. 22 and 23 are circuit diagrams of example LESD
`array interconnections.
`FIGS. 24-26 are simplified block diagrams of example
`control systems for use with the present invention.
`FIG. 27 is a side view of another reflector component
`embodiment for use with the present invention.
`
`65
`
`IPR PAGE 18
`
`

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`US 6,412,971 Bl
`
`15
`
`3
`FIG. 17 or other types of electrical connections such as
`solder bump techniques, can alternatively be used.
`If LESDs 14 have substrate surface 15 (FIG. 1) contact
`pads (shown as pads 34 in FIG. 6, for example), the LESDs
`can be attached by solder, ball grid array, or micro ball grid 5
`array techniques (represented by element 54 in FIGS. 6 and
`14) for example, for aiding in alignment of the LESDs. If the
`LESDs do not have metallization on substrate surfaces 15,
`then an adhesive such as a thermally conductive epoxy is
`useful for attachment purposes.
`FIG. 1 additionally illustrates a control device 20 situated
`in substrate 16. The control device can be coupled to the
`LESD array by any appropriate connection technique. As
`discussed below with respect to FIGS. 24-26, this can be
`useful for controlling the operation of the LESDs.
`Additionally, FIG. 1 illustrates a heat transfer device 76
`which, in one embodiment as shown for purposes of
`example, is coupled to surface 19 of substrate 16 for
`optimizing thermal management of the array. In embodi(cid:173)
`ments wherein a heat transfer device is used, a thermally
`conductive substrate such as sapphire, aluminum nitride,
`aluminum silicon carbide, diamond, or thermally conductive
`ceramic blends, for example, is useful. Cooling becomes
`important as the density and intensity of the emitted light 25
`increases. The heat transfer device may comprise a heat sink
`or a coolant assembly, for example. In one embodiment, the
`heat transfer device comprises a heat sink material such as
`aluminum silicon carbide, aluminum, aluminum nitride, or
`beryllium oxide. In another embodiment, thermoelectric 30
`cooling can be used. In still another embodiment, copper foil
`interconnections (not shown) can be used to route heat away
`from the LESDs. Another technique for thermal cooling is to
`selectively control lighting output of different LESDs of the
`light source. An associated control system is discussed with 35
`respect to FIGS. 24--26.
`FIGS. 3 and 4 are top and bottom views and FIGS. 5-7 are
`side views of different embodiments of LESDs for use in the
`embodiments of FIGS. 1 and 2. In these embodiments, each
`electrical connection 24 includes metallization 26 patterned 40
`over a portion of at least one side surface 17 of a respective
`LESD 14. These embodiments are useful because surfaces
`13 of LESDs 14 are not encumbered and allow easy appli(cid:173)
`cation of optional phosphors, reradiative components or
`reflector components (shown in FIGS. 10--20). Furthermore, 45
`in these embodiments, light emissions are not blocked by
`wire bonds.
`Electrical connections 24 can be fabricated in a similar
`manner as disclosed in commonly assigned Wojnarowski,
`now U.S. Pat. No. 5,888,884 U.S. application Ser. No.
`09/002,314, filed Jan. 2, 1998, where, in one embodiment, a
`semiconductor wafer includes a plurality of device active
`regions 22 separated by scribe lanes. Holes 30 are formed
`through the wafer within the scribe lanes. To prevent elec(cid:173)
`trical short circuits, an electrically insulating layer 28 is
`formed over all exposed surfaces of the wafer, front and
`back, including within the holes, and openings 27 are made
`in the insulating layer for access to top interconnection pads
`32. The wafer and holes are metallized and patterned to form
`bottom interconnection pads (in FIG. 4 shown as 34, 38, and
`42) on a bottom (substrate) surface electrically connected to
`corresponding top interconnection pads by metallization 26
`extending within the holes and metallization 31 on an active
`(first) surface of the wafer. Finally, a dicing saw is employed
`having a kerf width less than the diameter of the holes to 65
`separate the individual devices. Since the saw kerf width is
`less than the hole diameter, at each hole location a portion
`
`4
`of the metallized hole remains on each side of the cut,
`forming electrically conductive channels on the device
`edges extending top to bottom. This technique results in
`LESDs that can be positioned substantially edge-to-edge.
`Although the above paragraph describes one example of
`a method for forming electrical connections, other embodi(cid:173)
`ments can be used in the present invention. For example, if
`metallization 31 is appropriately plated over the top surface,
`it is not necessary that an LESD have a first surface
`10 interconnection pad 32. In another embodiment, a connec(cid:173)
`tion could be made through an insulated and metallized
`through hole situated within the device (preferably not on a
`location overlapping the active area) rather than on a side-
`wall. Contact pads on the bottom surfaces of the LESDs may
`be preformed or formed by the above discussed metalliza(cid:173)
`tion process and may comprise any desired form.
`Depending on the device, an input/output, bias, or cooling
`pad 35, shown in FIG. 5 may additionally be present or
`patterned on substrate surface 15 of an LESD. FIG. 5
`20 additionally illustrates an embodiment wherein rather than
`having metallization 26 extend to or form bottom contact
`pads, metallization 26 has a sufficient area to be electrically
`coupled to substrate contact pads 49.
`In one embodiment of the present invention, as shown in
`FIG. 6, substrate surface 15 of each LESD includes at least
`one substrate surface contact pad 34 and the substrate
`includes substrate contact pads 49, wherein metallization 26
`extends to the at least one substrate surface contact pad, and
`wherein the at least one substrate surface contact pad is
`aligned with at least one of the substrate contact pads.
`Substrate surface contact 34 may comprise a portion of
`metallization 26 or a separate contact pad to which metal(cid:173)
`lization 26 is electrically coupled. FIG. 6 additionally illus(cid:173)
`trates an optional phosphor coating 23 which can be applied
`as disclosed in aforementioned Srivastava et al., U.S. appli-
`cation Ser. No. 09/203,212.
`FIG. 6 additionally illustrates the use of alignment pins 52
`for LESD 14 and a multilayer interconnect structure 18. As
`discussed in aforementioned Wojnarowski, U.S. application
`Ser. No. 09/002,314, now U.S. Pat. No. 5,888,884 alignment
`pins can be used to properly align devices. In one
`embodiment, multilayer interconnect structure comprises a
`high density interconnect structure which is useful for
`coupling substrate surface contact pads 34 to device contact
`pads 21 of control device 20. In one embodiment control
`device 20 can by coupled to surface pads 23 by electrically
`conductive through posts 25, for example. Solder, electri(cid:173)
`cally conductive epoxy, or ball grid array material 54 is used
`50 in one embodiment to couple substrate contact pads 34 and
`substrate contact pads 49. Multilayer interconnect structure
`18, in one embodiment comprises a dielectric layer 46 such
`as a polymer attached to substrate 16 with an adhesive 44
`and having openings 50 extending to surface pads 23.
`55 Patterned metallization 48 then is formed and patterned to
`extend to surface pads 23 and form the substrate contact
`pads 49. Techniques for applying dielectric layers, forming
`openings, and applying and patterning metallization are
`described, for example, in Eichelberger et al., U.S. Pat. No.
`60 4,835,704.
`FIG. 7 illustrates an embodiment wherein the substrate on
`which substrate surfaces 15 of LESDs 14 rest is itself a
`multilayer interconnect structure 116 which may comprise
`layers of dielectric material and metallization. This embodi(cid:173)
`ment is useful for reducing potential stresses that can result
`from differing substrate and LESD coefficients of thermal
`expansion. If more structural support is desired, molding
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`material 58 can be formed around LESDs 14 with an
`optional mold frame 56. Molding techniques and techniques
`for coupling multilayer structures to electronic devices are
`described in Fillion et al., U.S. Pat. No. 5,353,498,
`Gorczyca, U.S. Pat. No. 5,492,586, Cole et al., U.S. Pat. No. 5
`5,527,741, and Wojnarowski et al., U.S. Pat. No. 5,567,657,
`for example.
`FIGS. 8 and 9 are side views showing embodiments of the
`present invention wherein a flexible and/or curved substrate
`216, 316 is included. The term "flexible" is intended to
`encompass substrates that are capable of being bent under
`normal conditions or substrates that can have their shapes
`altered by processes such as heat forming. In some
`situations, bending is facilitated by bonding or conforming
`a substrate to a curved surface (not shown). The degree of 15
`flexibility will depend on the material properties and the
`thickness of the substrate (which can be reduced by tech(cid:173)
`niques such as grinding, for example) and, to a limited
`extent, on the properties of LESDs 14. Flexible substrates
`are useful for providing light sources according to the
`present invention that are conformal to airplane cockpits and
`automobile dashboards, for example.
`In the embodiments of FIGS. 8 and 9, substrates 216 and
`316 have curved shapes and the arrays of LESDs form a
`curved arrays. In FIG. 8 the curved shape of substrate 216 25
`creates a convergent light pattern focusing to point 62,
`whereas in FIG. 9 the curved shape creates a divergent light
`pattern. Such patterns can be useful for directing light to
`desired locations. For example, convergent light is useful for
`a solid state flashlight or headlight.
`FIGS. 10-13 are side views of different embodiments of
`reradiative components 64, 78, 80, and 86 for use with the
`present invention. The optional use of reradiative compo(cid:173)
`nents and/or reflector components (shown in FIGS. 14-20)
`cost-effectively minimizes misdirected light that can be 35
`emitted from tops and sides of LESDs.
`In one embodiment, as shown in FIG. 10, the reradiative
`component comprises a plurality of lenses 64 with each lens
`being situated over a respective one of the LESDs. In one
`embodiment, lenses 64 are attached by a bonding glue (not 40
`shown), for example. In another embodiment, a droplet of a
`liquid lensing material can be deposited on each LESD
`which, when dried, forms a natural curvature lens due to
`surface tension or properties of the material. Solid lensing
`material can alternatively be placed on the die and heat 45
`refiowed and melted into shape. A laser or other cutting or
`etching device can be used to form one or more cuts or
`otherwise create one or more specific patterns 65 in the
`lenses to aid in focusing and light distribution control.
`In another embodiment, as shown in FIGS. 11-13, the 50
`reradiative component comprises a reradiative panel 78, 80,
`or 86. In the embodiment of FIG. 11, the reradiative panel
`comprises a fiat plate 78 that can be tinted to create a change
`in color of light emitted from LESDs 14, for example. In one
`embodiment the fiat plate comprises quartz, polymethyl- 55
`methacrylate (PMMA), or polyetherimide, for example,
`coated on either side by phosphors or layers of phosphors to
`provide a specific colored light. In the embodiments of
`FIGS. 12 and 13, the reradiative panel comprises a patterned
`sheet 80 or 86. Sheet 80 includes areas 82 including etched 60
`lines 84 which form focusing patterns for respective LESDs
`and operate in a similar manner as Frenel lenses. Patterned
`sheet 86 includes teeth portions 88 to aid in focusing. The
`reradiative panels can be placed adjacent or spaced apart
`from the LESDs. For patterned sheets, the patterned portion 65
`can be facing towards or away from the LESDs and may
`have optional phosphor layers patterned on either surface.
`
`30
`
`6
`Any of the above discussed reradiative components may
`be tinted or otherwise adapted to change the color of the
`light emitted by the LESDs. For example, the reradiative
`components can change infrared light to visible light or visa
`versa by the use of dyes or phosphors.
`FIGS. 14-20 and 27 are views of different embodiments
`of optional reflector components 66 or 166 for use with the
`present invention with each reflector component being situ(cid:173)
`ated to reflect light from a respective one of the LESDs 14.
`The reflector components are shaped to re-direct the maxi(cid:173)
`mum light emitted at odd angles from the LESDs so that
`such light is not lost and can be effectively used. Reflector
`components can be used with or without reradiative panels.
`Although the reflector components are shown as parabolic
`for purposes of example, other optimized reflector compo(cid:173)
`nent shapes can alternatively be used. As one example, using
`a stepped profile or a geometric profile can aide in forming
`a specific pattern of light.
`In one embodiment, as shown in FIGS. 14 and 15, a
`plurality of reflector components 66 and 166 are situated to
`reflect light from a respective one of the LESDs 14.
`Although there can be one reflector per LESD in one
`embodiment, in other embodiments, some LESDs have
`reflector components whereas other LESDs do not and/or
`some LEDs share a common reflector component. These
`reflector components can be useful for the LESD density for
`large area panel or wall or ceiling lighting technologies. As
`shown in FIGS. 14 and 15, the specific positioning of the
`reflector components is not critical. In FIG. 14 reflector
`components 66 extend to sides of the LESDs, whereas in
`FIG. 15 reflector components 166 extend to surfaces 13 of
`the LESDs. For LESDs that emit light form side surfaces 17
`in addition to or instead of top surfaces 13, it is useful to
`have a reflector component which reflects and does not
`block such side emitted light.
`FIGS. 16 and 17 illustrate embodiments wherein the
`reflector components 166 are used without reradiative com(cid:173)
`ponents. FIG. 17 further illustrates an embodiment wherein
`electrical connections 68 are used to provide electrical
`power to a respective LESD 14 comprises wire bonds. Wire
`bonds, although not providing the advantage of edge to edge
`placement of LESDs and limiting some types of applications
`of reflector components and reradiative components, may
`provide sufficient light in some applications, particularly
`with the use of reradiative components and/or reflector
`components.
`In the embodiments of FIGS. 18-20, the plurality of
`reflector components comprise an integral reflector compo(cid:173)
`nent assembly 70 having reflector portions 166. This
`embodiment is useful because the reflector components can
`be positioned simultaneously. In one embodiment, a layer of
`adhesive 72 comprising a material such as epoxy,
`polyethylene, or polytetrafiuoroethylene, for example, can
`be applied to the surfaces of substrate 16 or multilayer
`interconnection structure 18 if such structure forms part of
`substrate 16, and the reflector component assembly can be
`affixed to the adhesive.
`In one embodiment the reflector component assembly is
`fabricated by injection molding a plastic material and coat(cid:173)
`ing the injection molded material 167 with reflector portions
`166 comprising reflective material. Preferably injection
`molded material 167 comprises a material that can be
`molded to result in a smooth surface. Useful materials, for
`example, include polytetrafiuoroethylene, epoxy, or
`polyester, for example. The injection molded material may
`further comprise optional filler material such as glass or
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`ceramic particles, for example. After injection molding,
`reflector portions 166 can be applied over the surfaces. In
`one embodiment, reflector portions 166 comprise an adhe(cid:173)
`sion promoting material such as titanium covered by a
`reflective material such as aluminum or gold, for example.
`To prevent the reflective coating from extending to the
`substrate or along side surfaces of LESDs 14, spacers (one
`spacer 169 which is shown in FIG. 18 for purposes of
`example) can be used during the application of the reflective
`coating).
`FIG. 27 is a side view of another reflector component
`embodiment for use with the present invention. In this
`embodiment substrate 716 includes reflector component
`assembly 770 either as an integral or pre-attached assembly.
`Reflector portions 766 can be formed as discussed above 15
`with respect to reflector portions 166. LESDs 14 are then
`attached to the substrate/reflector component assembly com(cid:173)
`bination.
`In one embodiment, as shown in FIG. 27, the LESDs 14
`have non active area chip pads 34, and reflector portions 766
`and 866 serve both as light reflectors and as electrical
`couplers for coupling the LESDs. In this embodiment, area
`767 of curved surface 765 is not coated with reflective
`material (the reflective material can be blanketdeposited and
`then removed from areas 767 by etching), and the chip pads
`are coupled to reflector portions 766 and 866 with a bond
`780 comprising solder or a conductive adhesive, for
`example. FIG. 27 additionally shows a reflector component
`782 which has stepped portions 784 and angled portions
`786. Combinations of reflector components (which may 30
`have different profiles from steps, angles, and/or curves, for
`example, than adjacent reflector components) can be used to
`form virtually any desired light energy distribution
`(irradiance ).
`FIG. 21 is a view of one embodiment of the present
`invention wherein light source 100 has a light-bulb-shap