Case 2:20-cv-00038-JRG Document 1-6 Filed 02/14/20 Page 1 of 10 PageID #: 135
`
`Exhibit 5
`
`

`

`Case 2:20-cv-00038-JRG Document 1-6 Filed 02/14/20 Page 2 of 10 PageID #: 136
`
`USOO968.0068B2
`
`(12) United States Patent
`VO et al.
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 9,680,068 B2
`Jun. 13, 2017
`
`(54) QUANTUM DOT FILMS UTILIZING
`MULT-PHASE RESNS
`
`(71) Applicant: Nanoco Technologies, Ltd., Manchester
`(GB)
`
`(72) Inventors: Cong-Duan Vo, Manchester (GB);
`Imad Naasani, Manchester (GB);
`Amilcar Pillay Narrainen, Manchester
`(GB)
`
`(73) Assignee: Nanaco Technologies Ltd., Manchester
`(GB)
`
`(*) Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 312 days.
`(21) Appl. No.: 14/460,008
`(22) Filed:
`Aug. 14, 2014
`
`(65)
`
`Prior Publication Data
`US 2015/OO47765 A1
`Feb. 19, 2015
`
`O
`
`O
`
`Related U.S. Application Data
`(60) Provisional application No. 61/865,692, filed on Aug.
`14, 2013.
`
`(2011.01)
`(2010.01)
`(2006.01)
`(2006.01)
`(2006.01)
`
`(51) Int. Cl.
`B82. 20/00
`HOIL 33/50
`B32B 37/24
`C09K II/70
`C09K II/02
`(52) U.S. Cl.
`CPC ............ HOIL 33/504 (2013.01); B32B 37/24
`(2013.01); C09K II/02 (2013.01); C09K
`II/703 (2013.01); HOIL 33/502 (2013.01);
`B32B 2037/243 (2013.01); B32B 2307/418
`
`2OO
`
`
`
`(2013.01); B32B 2307/7242 (2013.01); B82Y
`20/00 (2013.01); Y10T 156/10 (2015.01)
`(58) Field of Classification Search
`CPC ...... H01L 33/502: C09K11/703: C09K11/02
`See application file for complete search history.
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`2010, 0123155 A1* 5, 2010 Pickett ................... B82Y 15.00
`
`2011/0068321 A1
`2011/0068322 A1
`2013, OO75692 A1
`
`3f2011 Picket et al.
`3/2011 Pickett et al.
`3/2013 Naasani et al.
`
`257/98
`
`FOREIGN PATENT DOCUMENTS
`
`EP
`
`2028248 A1
`
`2, 2009
`
`OTHER PUBLICATIONS
`
`Ramasamy et al. Materials Science in semiconductor Processing 42
`2016) 334-343.
`SAG. Male, 2007, 19, 6581.*
`Parlak et al. ACS Appl. Mater. Interfaces 2011, 3, 4306-4314.*
`Supporting information of Parlak 2011.*
`Wang et al. Langmuir 2005, 21, 2465-2473.*
`* cited by examiner
`Primary Examiner — Mark Kaucher
`(74) Attorney, Agent, or Firm — Blank Rome LLP
`
`ABSTRACT
`(57)
`Multi-phase polymer films containing quantum dots (QDS)
`are described herein. The films have domains of primarily
`hydrophobic polymer and domains of primarily hydrophilic
`polymer. QDS, being generally more stable within a hydro
`phobic matrix, are dispersed primarily within the hydropho
`bic domains of the films. The hydrophilic domains tend to be
`effective at excluding oxygen.
`
`1 Claim, 4 Drawing Sheets
`
`2O3
`
`

`

`Case 2:20-cv-00038-JRG Document 1-6 Filed 02/14/20 Page 3 of 10 PageID #: 137
`
`U.S. Patent
`
`Jun. 13, 2017
`
`Sheet 1 of 4
`
`US 9,680,068 B2
`
`104
`
`
`
`2O3
`
`

`

`Case 2:20-cv-00038-JRG Document 1-6 Filed 02/14/20 Page 4 of 10 PageID #: 138
`
`U.S. Patent
`
`Jun. 13, 2017
`
`Sheet 2 of 4
`
`US 9,680,068 B2
`
`
`
`008
`
`T08 :
`
`Z98
`
`

`

`Case 2:20-cv-00038-JRG Document 1-6 Filed 02/14/20 Page 5 of 10 PageID #: 139
`
`U.S. Patent
`
`Jun. 13, 2017
`
`Sheet 3 of 4
`
`US 9,680,068 B2
`
`ZOG & ```````
`
`.** **
`
`
`
`*** ** **
`
`*** <<. *** ***
`
`
`
`*** ***
`
`*
`**.
`
`*** **
`
`
`
`&
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`

`

`Case 2:20-cv-00038-JRG Document 1-6 Filed 02/14/20 Page 6 of 10 PageID #: 140
`
`U.S. Patent
`
`Jun. 13, 2017
`
`Sheet 4 of 4
`
`US 9,680,068 B2
`
`on N
`
`8
`
`s
`
`
`
`f i
`
`
`
`g
`8.
`x:
`
`3.
`
`anese: x,
`
`

`

`Case 2:20-cv-00038-JRG Document 1-6 Filed 02/14/20 Page 7 of 10 PageID #: 141
`
`1.
`QUANTUM DOT FILMS UTILIZING
`MULT-PHASE RESNS
`
`US 9,680,068 B2
`
`FIELD OF THE INVENTION
`
`The invention relates to materials comprising light emit
`ting semiconductor quantum dots (QDs), and more specifi
`cally, multi-phase polymer films incorporating QDS.
`
`BACKGROUND
`
`10
`
`15
`
`30
`
`35
`
`Light-emitting diodes (LEDs) are becoming more impor
`tant to modern day life and it is envisaged that they will
`become one of the major applications in many forms of
`lighting such as automobile lights, traffic signals, general
`lighting, liquid crystal display (LCD) backlighting and dis
`play screens. Currently, LED devices are typically made
`from inorganic solid-state semiconductor materials. The
`material used to make the LED determines the color of light
`produced by the LED. Each material emits light with a
`particular wavelength spectrum, i.e., light having a particu
`lar mix of colors. Common materials include AlGaAS (red),
`AlGalnP (orange-yellow-green), and AlGalnN (green-blue).
`LEDs that produce white light, which is a mixture of
`fundamental colors (e.g., red, green and blue) or that pro
`25
`duce light not available using the usual LED semiconductor
`materials are needed for many applications. Currently the
`most usual method of color mixing to produce a required
`color, such as white, is to use a combination of phospho
`rescent materials that are placed on top of the Solid-state
`LED whereby the light from the LED (the “primary light')
`is absorbed by the phosphorescent material and then re
`emitted at a different frequency (the “secondary light'). The
`phosphorescent material “down converts” a portion of the
`primary light.
`Current phosphorescent materials used in down convert
`ing applications typically absorb UV or blue light and
`convert it to light having longer wavelengths, such as red or
`green light. A lighting device having a blue primary light
`Source. Such as a blue-emitting LED, combined with sec
`ondary phosphors that emit red and green light, can be used
`to produce white light.
`The most common phosphor materials are solid-state
`semiconductor materials, such as trivalent rare-earth doped
`oxides or halophosphates. White emission can be obtained
`by blending a blue light-emitting LED with a green phos
`phor such as, SrGaSa:Eu" and a red phosphor such as,
`SrSisNis:Eu" or a UV light-emitting LED plus a yellow
`phosphor such as, Sr.P.O., Eu"; Mu", and a blue-green
`phosphor. White LEDs can also be made by combining a
`blue LED with a yellow phosphor.
`Several problems are associated with solid-state down
`converting phosphors. Color control and color rendering
`may be poor (i.e., color rendering index (CRI)<75), resulting
`in light that is unpleasant under many circumstances. Also,
`it is difficult to adjust the hue of emitted light; because the
`characteristic color emitted by any particular phosphor is a
`function of the material the phosphor is made of. If a suitable
`material does not exist, then certain hues may simply be
`unavailable. There is thus a need in the art for down
`converting phosphors having greater flexibility and better
`color rendering than presently available.
`
`40
`
`45
`
`50
`
`55
`
`60
`
`SUMMARY
`
`Films containing QDs are described herein. The films may
`be used as components for LED lighting devices, particu
`
`65
`
`2
`larly, as phosphor films for down-converting light emitted
`from a solid-state LED semiconductor material.
`The films are formed from two or more polymer materi
`als, for example, two or more polymer resins. The films at
`least partially phase-separate. Such that some domains
`within a film are primarily one of the polymer materials and
`other domains within the film are primarily the polymer
`material. One of the polymer materials is chosen to be highly
`compatible with the QDs. Another of the polymer materials
`is highly effective at excluding oxygen. As a result, the
`multi-domain films include QD-rich domains of QDs dis
`persed in the QD-compatible polymer, those domains being
`Surrounded by QD-poor domains of the oxygen-excluding
`polymer. Thus, the QDs are suspended in a medium with
`which they are highly compatible and are protected from
`oxygen by the oxygen-excluding domains.
`Methods of making such films are also described herein.
`According to some embodiments, QDS are suspended in a
`Solution of a first polymer resin (i.e., a QD-compatible
`resin). The QD suspension is then added to a solution of the
`second polymer resin (the oxygen-excluding resin), yielding
`an emulsion. A film is formed of the emulsion, which can
`then be cured to form a solid film.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`The foregoing Summary as well as the following detailed
`description will be better understood when read in conjunc
`tion with the appended drawings. For the purpose of illus
`tration only, there is shown in the drawings certain embodi
`ments. It is understood, however, that the inventive concepts
`disclosed herein are not limited to the precise arrangements
`and instrumentalities shown in the drawings.
`FIG. 1 is a schematic illustration of a prior art use of a film
`containing QDs to down-convert light emitted by a LED.
`FIG. 2 is a schematic illustration of a QD-containing
`polymer sandwiched between transparent sheets.
`FIG. 3 is a schematic illustration of a two-phase film
`having a QD-compatible phase and an oxygen-excluding
`phase.
`FIG. 4 is a flowchart illustrating the steps of making a
`two-phase film.
`FIG. 5 is a plot of QD quantum yields in various films.
`FIG. 6 illustrates stability studies of two-phase LMA/
`epoxy films.
`
`DESCRIPTION
`
`There has been substantial interest in exploiting the
`properties of compound semiconductor particles with
`dimensions on the order of 2-50 nm, often referred to as
`quantum dots (QDS) or nanocrystals. These materials are of
`commercial interest due to their size-tunable electronic
`properties that can be exploited in many commercial appli
`cations.
`The most studied of semiconductor materials have been
`the chalcogenides II-VI materials namely ZnS, ZnSe, CdS,
`CdSe, CdTe; especially CdSe due to its tunability over the
`visible region of the spectrum. Reproducible methods for the
`large-scale production of these materials have been devel
`oped from “bottom up' techniques, whereby particles are
`prepared atom-by-atom, i.e., from molecules to clusters to
`particles, using 'wet' chemical procedures.
`Two fundamental factors, both related to the size of the
`individual semiconductor nanoparticles, are responsible for
`their unique properties. The first is the large surface-to
`volume ratio. As particles become smaller, the ratio of the
`
`

`

`Case 2:20-cv-00038-JRG Document 1-6 Filed 02/14/20 Page 8 of 10 PageID #: 142
`
`US 9,680,068 B2
`
`10
`
`15
`
`4
`Films containing QDs are described herein. FIG. 1 illus
`trates a prior art embodiment 100, wherein a QD-containing
`film 101 is disposed on a transparent substrate 102. Such a
`film can be useful, for example, to down-convert primary
`light 103 from a primary light source 104 by absorbing
`primary light 103 and emitting secondary light 105. A
`portion 106 of primary light may also be transmitted through
`the film and Substrate so that the total light emanating from
`the film and substrate is a mixture of the primary and
`secondary light.
`QD-containing films, such as film 101 in FIG. 1, may be
`formed by dispersing QDS in a polymer resin material and
`forming films of the material using generally any method of
`preparing polymer films known in the art. It has been found
`that QDs are generally more compatible with hydrophobic
`resins, such as acrylates, compared to more hydrophilic
`resins, such as epoxies. Thus, polymer films made of QDS
`dispersed in acrylates tend to have higher initial quantum
`yields (QYs) than QD films using hydrophilic resins such as
`epoxy resins. However, acrylates tend to be permeable to
`oxygen, while epoxy resin polymers and similar hydrophilic
`polymers tend to be better at excluding oxygen.
`One alternative for achieving high QY associated with
`QD-containing hydrophobic films, while also maintaining
`stability of the QY over time, is to insulate the film from
`oxygen by Sandwiching the film between gas barrier sheets,
`as illustrated in FIG. 2. FIG. 2 illustrates a panel 200 having
`a polymer film 201 contained between gas barrier sheets 202
`and 203. The polymer film 201 contains QDs dispersed
`throughout. Gas barrier sheets 202 and 203 serve to prevent
`oxygen from contacting the dispersed QDS. However, even
`in an embodiment as illustrated in FIG. 2, oxygen can
`permeate into the film at edges 204, resulting in a deterio
`ration of the QY of the film.
`One solution to this problem is to seal edges 204 with an
`oxygen barrier. However, doing so adds cost to the produc
`tion of panel 200. Another option is to use a polymer 201
`that is less permeable to oxygen. But as explained above,
`QDS are generally less compatible with Such polymer resins,
`and therefore the optical properties of devices utilizing such
`polymers are less than ideal.
`Multi-phase films utilizing at least a first phase (phase 1)
`resin that is compatible with the QD material and at least a
`second phase (phase 2) resin that is efficient at rejecting O
`are described herein. FIG. 3 illustrate a plan view of such a
`film 300, wherein QDS 301 are dispersed in a first polymer
`phase 302, which is typically a hydrophobic material such as
`an acrylate resin. Regions of the first polymer phase are
`dispersed throughout a second polymer phase 303, which is
`typically an oxygen-impermeable material Such as epoxy.
`The multi-phase films described herein overcome many of
`the problems described above. The phase 1 resin is compat
`ible with the QDs and therefore allows a high initial QY. The
`phase 2 resin is impermeable to oxygen, and therefore
`protects the QDs from oxidation without the need to seal the
`edges of the panel. As used herein, the term “film' includes,
`not only 2-dimensional (i.e. flat) sheets, as illustrated in
`FIGS. 1-3, but can also include 3-dimensional shapes.
`FIG. 4 is a flowchart illustrating steps of a method of
`preparing multi-phase films as described herein. The QDs
`are dispersed in a solution of the phase 1 resin (or resin
`monomer) 401. As described above, the phase 1 resin is
`generally a hydrophobic resin, such as acrylate resins.
`Examples of Suitable phase 1 resins include, poly(methyl
`(meth)acrylate), poly(ethyl(meth)acrylate), poly(n-propyl
`(meth)acrylate), poly(butyl(meth)acrylate), poly(n-pentyl
`(meth)acrylate),
`poly(n-hexyl(meth)acrylate),
`poly
`
`3
`number of Surface atoms to those in the interior increases.
`This leads to the Surface properties playing an important role
`in the overall properties of the material. The second factor is
`a change in the electronic properties of the material when the
`material is very small in size. At extremely small sizes
`quantum confinement causes the materials band gap to
`gradually increase as the size of the particles decrease. This
`effect is a consequence of the confinement of an electron in
`a box giving rise to discrete energy levels similar to those
`observed in atoms and molecule rather than a continuous
`band as observed in the corresponding bulk semiconductor
`material. Thus, the “electron and hole' produced by the
`absorption of electromagnetic radiation are closer together
`than they would be in the corresponding macrocrystalline
`material. This leads to a narrow bandwidth emission that
`depends upon the particle size and composition of the
`nanoparticle material. QDs therefore have higher kinetic
`energy than the corresponding macrocrystalline material and
`consequently the first excitonic transition (band gap)
`increases in energy with decreasing particle diameter.
`QD nanoparticles of a single semiconductor material tend
`to have relatively low quantum efficiencies due to electron
`hole recombination occurring at defects and dangling bonds
`situated on the nanoparticle Surface, which may lead to
`non-radiative electron-hole recombinations. One method to
`eliminate Such defects and dangling bonds on the inorganic
`Surface of the QD is to grow a second inorganic material,
`having a wider band-gap and Small lattice mismatch to that
`of the core material, epitaxially on the surface of the core
`particle, producing a “core-shell particle. Core-shell par
`ticles separate any carriers confined in the core from surface
`states that would otherwise act as non-radiative recombina
`tion centers. One example is QDS having a ZnS shell grown
`on the surface of a CdSe core.
`Rudimentary QD-based light-emitting devices have been
`made by embedding colloidally produced QDs in an opti
`cally clear LED encapsulation medium, typically a silicone
`or an acrylate, which is then placed on top of a Solid-state
`LED. The use of QDs potentially has some significant
`advantages over the use of the more conventional phos
`phors, such as the ability to tune the emission wavelength,
`strong absorption properties, improved color rendering, and
`low scattering.
`For the commercial application of QDS in next-generation
`light-emitting devices, the QDS are preferably incorporated
`into the LED encapsulating material while remaining as
`fully mono-dispersed as possible and without significant
`loss of quantum efficiency. The methods developed to date
`are problematic, not least because of the nature of current
`LED encapsulants. QDS can agglomerate when formulated
`into current LED encapsulants, thereby reducing the optical
`performance of the QDs. Moreover, once the QDs are
`incorporated into the LED encapsulant, oxygen can migrate
`through the encapsulant to the surfaces of the QDs, which
`can lead to photo-oxidation and, as a result, a drop in
`quantum yield (QY).
`One way of addressing the problem of oxygen migration
`to the QDs has been to incorporate the QDs into a medium
`with low oxygen permeability to form “beads of such a
`material containing QDs dispersed within the bead. The
`QD-containing beads can then be dispersed within an LED
`encapsulant. Examples of such systems are described in U.S.
`patent application Ser. No. 12/888,982, filed Sep. 23, 2010
`(Pub. No.: 2011/0068322) and Ser. No. 12/622,012, filed
`Nov. 19, 2009 (Pub. No.: 2010/0123155), the entire contents
`of which are incorporated herein by reference.
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`

`

`Case 2:20-cv-00038-JRG Document 1-6 Filed 02/14/20 Page 9 of 10 PageID #: 143
`
`US 9,680,068 B2
`
`6
`are incorporated herein by reference. The QDs were added
`to a degassed vial, the toluene evaporated, and the resultant
`Solid QD re-dispersed in degassed lauryl methacrylate
`(LMA, 2.64 mL) containing IRG819/IRG651 (Igracure(R)
`photoinitiators (9/18 mg). Trimethylolpropane trimethacry
`late (TMPTM) crosslinker (0.32 mL) was added. The mix
`ture was further stirred for 30 min under nitrogen affording
`phase 1 resin. Films of QDs in phase 1 resin were laminated
`between 3M gas barrier layers on an area limited by a 19
`mmx 14 mmx0.051 mm plastic spacer. The film was cured
`with a Mercury lamp for 1 min. Stability testing of the QY
`of the QDS in phase 1 resin is represented by square data
`points in the plot illustrated in FIG. 5.
`Example 1B
`
`Two-phase resin was prepared by mixing 148 microliters
`of the phase 1 resin with 0.5 mL degassed epoxy (Epotek,
`OG142) and the mixture was mechanically stirred for 3 min
`at 100 rpm under nitrogen. 60 Microliters of the two-phase
`resin was then laminated between 3M gas barrier layers on
`an area limited by a 19 mmx 14 mmx0.051 mm plastic
`spacer. The film was cured with a Mercury lamp for 1 min.
`Stability testing of the QY of the QDs in two-phase resin
`comprising acrylate (phase 1) and epoxy (Epotek OG142,
`phase 2) is represented by diamond-shaped data points in the
`plot illustrated in FIG. 5.
`Example 2
`
`Green InP/ZnS QDs (120 Optical Density (OD)) were
`prepared as described in U.S. patent application Ser. No.
`13/624,632, filed Sep. 23, 2011. The QDs were added to a
`degassed vial and dispersed in degassed lauryl methacrylate
`(LMA, 2.64 mL) containing IRG819/IRG651 photoinitia
`tors (9/18 mg). TMPTM crosslinker (0.32 mL) was added.
`The mixture was further stirred for 30 min under nitrogen
`affording phase 1 resin. Two-phase resin was prepared by
`mixing 148 microliters of the phase 1 resin with 0.5 mL
`degassed polyurethane acrylate (Dymax OP4-4-26032) and
`the mixture was mechanically stirred for 3 min at 100 rpm
`under nitrogen. 60 Microliters of the two-phase resin was
`then laminated between 3M gas barrier layers on an area
`limited by a 19 mmx14 mmx0.051 mm plastic spacer. The
`film was cured with a Mercury lamp for 1-5 min. Stability
`testing of the QY of the QDs in two-phase resin comprising
`acrylate (phase 1) and polyurethane acrylate (Dymax OP-4-
`26032, phase 2) is represented by triangle-shaped data
`points in the plot illustrated in FIG. 5.
`Example 3
`
`Green InP/ZnS QDs (120 Optical Density (OD)) were
`prepared as described in U.S. patent application Ser. No.
`13/624,632, filed Sep. 23, 2011. The QDs were re-dispersed
`in degassed lauryl methacrylate (LMA, 1.2 mL) by Stirring
`under nitrogen overnight. IRG819 photoinitiator (3 mg) was
`dissolved in 0.6 mL of the QD dispersion in LMA. TMPTM
`crosslinker (0.073 mL) was then added. The mixture was
`further stirred for 30 min under nitrogen, affording phase 1
`resin with QD concentration at 89.2 OD/mL. Two-phase
`resin was obtained by mixing 67 microliters of phase 1 resin
`with 0.43 mL degassed epoxy (Epotek, OG142), upon which
`the mixture was mechanically stirred for 3 min at 100 rpm
`under nitrogen. 60 Microliters of the two-phase resin was
`then laminated between 3M gas barrier layers on an area
`
`5
`hexyl(meth)
`poly(2-ethyl
`(cyclohexyl(meth)acrylate),
`acrylate), poly(octyl(meth)acrylate), poly(isooctyl(meth)
`acrylate), poly(n-decyl(meth)acrylate), poly(isodecyl(meth)
`acrylate), poly(lauryl(meth)acrylate), poly(hexadecyl(meth)
`acrylate), poly(octadecyl(meth)acrylate), poly(isobornyl 5
`(meth)acrylate), poly(isobutylene), polystyrene, poly
`(divinyl benzene), polyvinyl acetate, polyisoprene,
`polycarbonate, polyacrylonitrile, hydrophobic cellulose
`based polymers like ethyl cellulose, silicone resins, poly
`(dimethyl siloxane), poly(vinyl ethers), polyesters or any 10
`hydrophobic host material Such as wax, paraffin, vegetable
`oil, fatty acids and fatty acid esters.
`Generally, the phase 1 resin can be any resin that is
`compatible with the QDs. The phase 1 resin may or may not
`be cross-linked or cross-linkable. The phase 1 resin may be 15
`a curable resin, for example, curable using UV light. In
`addition to the QDS and phase 1 resin (or resin monomer),
`the solution of 401 may further include one or more of a
`photoinitiator, a cross-linking agent, a polymerization cata
`lyst, a refractive index modifier (either inorganic one such as 20
`ZnS nanoparticles or organic one Such as high refractive
`index monomers or poly(propylene Sulfide)), a filler Such as
`fumed silica, a scattering agent Such as barium sulfate, a
`Viscosity modifier, a Surfactant or emulsifying agent, or the
`like.
`The QD-phase 1 resin dispersion can then be mixed with
`a solution of the phase 2 resin (or resin monomer) 402. As
`explained above, the phase 2 resin is a better oxygen barrier
`than the phase 1 resin. The phase 2 resin is generally a
`hydrophilic resin. The phase 2 resin may or may not be 30
`cross-linkable. The phase 2 resin may be a curable resin, for
`example, curable using UV light. Examples of phase 2 resins
`include epoxy-based resins, polyurethanes-based resins,
`hydrophilic (meth)acrylate polymers, polyvinyl alcohol,
`poly(ethylene-co-vinyl alcohol), polyvinyl dichloride, sili- 35
`cones, polyimides, polyesters, polyvinyls, polyamides,
`enphenolics, cyanoacrylates, gelatin, water glass (sodium
`silicate), PVP (Kollidon). The solution of phase 2 resin may
`also include one or more of a photoinitiator, a cross-linking
`agent, a polymerization catalyst, a Surfactant or emulsifying 40
`agent, or the like.
`According to some embodiments, the phase 1-phase 2
`mixture forms an emulsion 403, typically and emulsion of
`phase 1 resin Suspended in phase 2 resin. The emulsion
`composition can be adjusted by adjusting the relative con- 45
`centrations of phase 1 and phase 2 resins, the rate of Stirring
`of the mixture, the relative hydrophobicity of the resins, and
`the like. One or more emulsifying agents, Surfactants, or
`other compounds useful for Supporting stable emulsions
`may be used.
`According to certain embodiments, such as the embodi
`ment illustrated in FIG. 2, the resin mixture is laminated
`between gas barrier films 404. Examples of gas barrier films
`include FTB3-50 (available from 3M, St. Paul, Minn.) and
`GX50W or GX25W (available from Toppan Printing Co., 55
`LT, Japan). Upon curing 405, the laminated resin film yields
`a polymer film having regions of phase 1 polymer, contain
`ing QDS, dispersed throughout phase 2 polymer, as illus
`trated in FIG. 3.
`
`25
`
`50
`
`EXAMPLES
`
`Example 1A
`
`60
`
`Green InP/ZnS QDs (120 Optical Density (OD)) were 65
`prepared as described in U.S. patent application Ser. No.
`13/624,632, filed Sep. 23, 2011, the entire contents of which
`
`

`

`Case 2:20-cv-00038-JRG Document 1-6 Filed 02/14/20 Page 10 of 10 PageID #: 144
`
`7
`limited by a 19 mm x 14 mmx0.051 mm plastic spacer. The
`films were cured with a Mercury lamp for 1 min.
`
`US 9,680,068 B2
`
`8
`
`Effect of Refractive Index of Phase
`2 Resin (RI of phase 1 resin = 1.47).
`
`Example 4
`
`5
`
`Sam
`ple
`
`Initial Initial Phase 2
`QY EQE Resin
`
`10
`
`15
`
`25
`
`30
`
`35
`
`Green InP/ZnS QDs (120 Optical Density (OD)) were
`prepared as described in U.S. patent application Ser. No.
`13/624,632, filed Sep. 23, 2011. The QDs were dispersed in
`degassed lauryl methacrylate (LMA, 2.64 mL) containing
`IRG819/IRG651 photoinitiators (9/18 mg) by stirring under
`nitrogen overnight. TMPTM crosslinker (0.32 mL) was
`added. The mixture was further stirred for 30 min under
`nitrogen affording phase 1 resin. Non-crosslinkable, non
`Viscous acrylate phase 2 resin was prepared by dissolving
`10.1 mg IRG819 in deoxygenated glycidyl methacrylate
`(GMA, 1 mL). Non-crosslinkable, viscous acrylate phase 2
`resin was prepared by dissolving polyvinylidene chloride
`(PVDC, Saran F310, 1.5 g) in deoxygenated GMA/IRG819/
`IRG651 (8.5 mL/57.5 mg/115.3 mg) solution. Two-phase
`resin was obtained by mixing 148 microliters of the phase 1
`resin with 0.5 mL degassed phase 2 resin and the mixture
`was mechanically stirred for 3 min at 100 rpm under
`nitrogen. 60 microliters of the two-phase resin was then
`either added to the well of a 19 mmx14 mm glass plate or
`laminated between 3M gas barrier layers on an area limited
`by a 19 mmx14mmx0.051 mm plastic spacer. The film was
`finally cured with Mercury lamp for 5 min.
`Stability of Resin Films
`FIG. 5 is a plot illustrating the quantum yield of resin
`films of QDs upon exposure to a blue backlight unit (BLU)
`for amounts of time (time, in days, denoted on the X-axis).
`The QY of green QDs in a single-phase LMA resin, as
`prepared in Example la above, is represented by Square data
`points 501. The single-phase resin film has an initial QY of
`about 60%, but the QY drops substantially during the first
`week of exposure.
`Diamond-shaped data points 502 represent the QY of a
`two-phase film of LMA/epoxy resin containing QDS pre
`pared as describe in Example 1b above. The initial QY of the
`LMA/epoxy two-phase film is also about 60%, but unlike
`that of the single-phase film, the QY of the two-phase film
`remains constant over the time period of the experiment. The
`stability of the QY indicates that the two-phase film effec
`tively prevents oxidation of the QDs.
`Triangle-shaped data points 503 represent QY a two
`phase film of QDs in LMA/polyurethane acrylate, as pre
`pared in Example 2 above. The initial QY of the LMA/
`50
`polyurethane acrylate film is about 45% and remains stable
`for over three months. FIG. 6 illustrates stability studies of
`the two-phase LMA/epoxy film prepared in Example 1b.
`LED intensity 601, efficacy 602, photoluminescence inten
`sity 603, QD/LED ratio 604, and % EQE 605 remain stable
`and above T70 606 for at least 2000 hours.
`Effect of Refractive Index of Phase 2 Resin
`The phase 1 LMA resin used in the above Examples has
`a refractive index (RI) of 1.47. Table 1 illustrates the effect
`of the RI of the phase 2 resin effects the optical properties
`of the two-phase films.
`
`40
`
`45
`
`55
`
`60
`
`RI of cured
`Phase 2 Resin
`
`2-phase 2-phase
`QY
`EQE
`
`1.47
`
`60
`
`72
`
`1.55
`
`S4
`
`59
`
`1.58
`
`59
`
`58
`
`1
`
`60
`
`69
`
`69 Urethane
`acrylate (OP4
`4-20639)
`Urethane
`acrylate
`(Dymax OP4
`4-26032)
`Epoxy
`(Epotek
`OG142)
`
`69
`
`As shown in Table 1, when the RI of the first phase and
`that of the second phase are matched, the initial QY and
`EQE of the film is maximized. When there is mismatch
`between the RIs of the first and second phase resins, the
`initial QY and EQE of the film is reduced. Thus, it is
`beneficial, where possible, to use first and second phase
`resins that have closely matched RIs. According to some
`embodiments, the RIs of the two resins differ by less than
`about 5%. According to some embodiments, the RIs of the
`two resins differ by less than about 1%.
`Accordingly, additives such as Surfactants, viscosity
`modifiers, monomers, light scattering agents, and other
`inorganic Surface tension modifiers may be used to adjust the
`RI of one or both phases so that the RIs match. Such
`additives may also be used to minimize chemical interaction
`between the phases. Moreover, chemical anti-oxidants (di
`laurylthiodipropionate, octadecylsulfide, octadecanethiol,
`cholesteryl palmitate, Zinvisible, ascorbic acid palmitate,
`alpha tocopherol, BHA, BHT, octane thiol, lipoic acid,
`gluthathion, sodium metabisulfite, trioctyl phosphine (TOP),
`tetradecylphosphonic acids, polyphenols) may be added to
`one or both phases to minimize the degradation of QDS
`around the edges of the two-phase/gas barrier encapsulated
`QD films.
`The inventive concepts set forth herein are not limited in
`their application to the construction details or component
`arrangements set forth in the above description or illustrated
`in the drawings. It should be understood that the phraseology
`and terminology employed herein are merely for descriptive
`purposes and should not be considered limiting. It should
`further be understood that any one of the described features
`may be used separately or in combination with other fea
`tures. Other invented Systems, methods, features, and advan
`tages will be or become apparent to one with skill in the art
`upon examining the drawings and the detailed description
`herein. It is intended that all such additional systems,
`methods, features, and advantages be protected by the
`accompanying claims.
`What is claimed is:
`1. A method of preparing a film, the method comprising:
`forming an emulsion comprising a first phase that com
`prises a first polymer and quantum dots and a second
`phase that comprises a second polymer;
`depositing the emulsion between gas barrier sheets to
`form a film; and
`curing the first and second polymers.
`
`k
`
`k
`
`k
`
`k
`
`k
`
`