  United States Court of Appeals
      for the Federal Circuit
                ______________________

                 DOME PATENT L.P.,
                  Plaintiff-Appellant

                           v.

MICHELLE K. LEE, DIRECTOR, U.S. PATENT AND
           TRADEMARK OFFICE,
              Defendant-Appellee.
            ______________________

                      2014-1673
                ______________________

    Appeal from the United States District Court for the
District of Columbia in No. 1:07-CV-01695.
                 ______________________

              Decided: September 3, 2015
               ______________________

    JAMES W. DABNEY, Hughes Hubbard & Reed LLP,
New York, NY, argued for plaintiff-appellant. Also repre-
sented by MITCHELL EPNER, STEPHEN S. RABINOWITZ.

    SCOTT WEIDENFELLER, Office of the Solicitor, United
States Patent and Trademark Office, Alexandria, VA,
argued for defendant-appellee.   Also represented by
NATHAN K. KELLEY, WILLIAM LAMARCA.
               ______________________

  Before REYNA, SCHALL, and HUGHES, Circuit Judges.
2                                   DOME PATENT L.P.   v. LEE



HUGHES, Circuit Judge.
    Dome owns a patent for making contact-lens material.
On reexamination, the U.S. Patent and Trademark Office
found that the claimed method at issue was obvious and
therefore unpatentable. The district court agreed with
the Patent Office that the claimed method was unpatent-
able. On appeal, Dome challenges both the standard of
review employed by the district court and the court’s
ultimate conclusion on obviousness. Because we conclude
that the district court applied the proper legal standard
and because its factual findings were not clearly errone-
ous, we affirm.
                             I
    Dome owns U.S. Patent No. 4,306,042, which concerns
the polymer science behind making contact-lens materials
that are rigid and gas permeable. During the relevant
time period, contact-lens makers required contact-lens
materials to be optically clear, sufficiently rigid for ma-
chining and polishing, oxygen permeable, and hydrophilic.
To meet these four requirements, contact-lens makers
used plastic polymers.
    A polymer is a chain or network of molecules called
monomers. The process of synthesizing a polymer from
monomers of a single type is called polymerization. When
two or more different types of monomers are reacted, i.e.,
copolymerized, a copolymer is formed and the constituent
compounds are known as comonomers. Polymers or
copolymers can have many different structures, including
linear chains, branched chains, cross-linked networks,
and mixtures thereof.
    Contact-lens makers can produce materials that have
varying physical properties by varying the types of mon-
omers used and the resulting polymer’s structure. For
example, using one type of cross-linking agent over an-
other may increase the gaps in a polymer’s structure,
DOME PATENT L.P.   v. LEE                               3



affecting oxygen permeability.     Or using hydrophilic
monomers, sometimes referred to as “wetting agents,” in a
linear polymer chain can increase the polymer’s ability to
attract or hold water. By contrast, using hydrophobic
monomers to create a polymer can decrease the polymer’s
affinity for water.
     The first practical plastic contact lens was made of
plexiglass, or polymethyl methacrylate (PMMA). Alt-
hough clear, rigid, and hydrophilic, PMMA was not suffi-
ciently oxygen permeable to allow users to wear the
lenses for extended periods of time. After a few hours, a
user had to remove PMMA lenses to allow the cornea to
absorb ambient oxygen, which is needed to ensure, among
other things, that the eye’s cells and nerves remain
healthy. Given these limitations on PMMA lenses, poly-
mer scientists began exploring other combinations of
monomer types and polymer structures to create a mate-
rial similar to PMMA, but with increased oxygen permea-
bility.
    In the early 1970’s, major advances in polymer science
led to the discovery that silicone could be incorporated
into plastics by mixing siloxane-based compounds with
methyl methacrylate (MMA), a monomer in PMMA. One
particular siloxane-based compound known as “Tris,” or
1,1,1-tris(trimethylsiloxy)methacryloxypropylsilane, was
identified as a strong candidate because, when mixed
with MMA, it led to materials with exceptional oxygen
permeability. A significant drawback to this combination,
however, was that Tris is hydrophobic, and it caused the
polymer to be hydrophobic. To offset this drawback,
polymer scientists in the late 1970’s and the 1980’s would
combine other hydrophilic comonomers, wetting agents,
and cross-linking agents with Tris, hoping to strike an
acceptable balance between oxygen permeability, optical
clarity, rigidity, and hydrophilicity.
4                                   DOME PATENT L.P.   v. LEE



    Claim 1 of the ’042 patent covers a method of making
one such combination. The method comprises making
Tris and then copolymerizing it with an ester of acrylic or
methacrylic acid (e.g., MMA), a surface wetting agent,
and an oxygen permeable siloxane-based cross-linking
agent (a multifunctional 1 siloxanyl alkyl ester). Claim 1
recites, in relevant part:
    A method of making an oxygen permeable materi-
    al for the manufacture of contact lens by the syn-
    thesization     of    the     monomer       1,1,1-
    tris(methylsiloxy)methacryloxypropylsilane
    (a siloxanyl alkyl ester) by the following proce-
    dures: . . .
    (f) forming an oxygen permeable contact lens ma-
    terial by copolymerizing from 5% to 90% by
    weight      of   the     1,1,1-tris(trimethylsiloxy)
    methacryloxypropylsilane prepared above; 3% to
    90% by weight of an ester of acrylic or methacrylic
    acid; from 0.05% to 90% by weight of a surface
    wetting agent, from 0.01% to 90% by weight of an
    oxygen permeable crosslinking agent selected
    from the class of multifunctional siloxanyl alkyl
    esters in the presence of a free radical or a photo
    initiator.
’042 patent, col. 5 ll. 38–64.
    In December 1997, Dome filed suit against six makers
of contact lenses for alleged infringement of the ’042
patent. Shortly after, one defendant requested ex parte


    1   Copolymers with cross-linked networks, such as
the types covered by the ’042 patent, can be formed by
employing a “multifunctional” comonomer. Two or more
ends of a multifunctional comonomer have the ability to
join with other comonomers to form a cross-link between
polymer chains, like a rung of a ladder.
DOME PATENT L.P.   v. LEE                                       5



reexamination of the ’042 patent. See 35 U.S.C. § 302
(1994). In June 1999, the Patent Office ordered reexami-
nation and, as a result, the district court stayed litigation
pending a final determination in the reexamination
proceeding. The Patent Office confirmed the patentability
of claims 2, 3, and 4 of the ’042 patent, but it found claim
1 obvious under 35 U.S.C. § 103(a) (2006).
     Dome then filed suit in September 2007 against the
Patent Office in the United States District Court for the
District of Columbia under 35 U.S.C. §§ 145 and 306
(2006), requesting that the district court enjoin the Patent
Office from cancelling claim 1 of the ’042 patent and that
it direct the Patent Office to issue a reexamination certifi-
cate under 35 U.S.C. § 307 (2006). Following a bench
trial, the district court held claim 1 of the ’042 patent
invalid as obvious under 35 U.S.C. § 103 and entered
judgment in favor of the Patent Office.
    The district court concluded that the ’042 patent
would have been obvious to a person of ordinary skill at
the time of filing in view of the prior art, including U.S.
Patent Nos. 4,120,570 (Gaylord), 4,152,508 (Ellis), and
4,235,985 (Tanaka).
    Gaylord discloses a polymer for making rigid, gas-
permeable contact lenses. Gaylord’s disclosures represent
a significant breakthrough in contact-lens materials. It is
one of the first teachings of using siloxane-based mono-
mers, including Tris, with MMA for the purpose of mak-
ing contact lenses. In fact, the record indicates that Tris
and similar siloxane-based compounds became an “indus-
try standard” in the manufacture of contact lenses follow-
ing this breakthrough. J.A. 2085.
    Gaylord teaches that a suitable polymer can be made
by combining Tris, MMA, methacrylic acid as a hydro-
philic wetting agent, and a hydrophilic cross-linking
agent, such as ethylene glycol dimethacrylate. See Gay-
lord col. 1 l. 53 – col. 2 l. 44; col. 3 ll. 63–65; col. 5 ll. 39–
6                                        DOME PATENT L.P.    v. LEE



51; col. 6 ll. 3–12. But unlike the ’042 patent, Gaylord
does not teach using a hydrophobic, siloxane-based cross-
linking agent. See Gaylord col. 6 ll. 3–12.
     Ellis discloses a “silicone-containing hard contact lens
material” that, like Gaylord, can include Tris, MMA, a
hydrophilic wetting agent, and a hydrophilic cross-linking
agent, including ethylene glycol dimethacrylate. Ellis
col. 1 ll. 1–3; col. 3 ll. 7–24; col. 3 ll. 64–68; col. 4 ll. 24–27;
col. 4 ll. 4–7. Ellis also teaches the inclusion of a fifth
monomer called an itaconate ester, which “gives increased
rigidity, hardness and some degree of wettability.” Ellis
col. 2 ll. 1–3.
    Tanaka discloses a polymer suitable for continuous-
wear contact lenses, and it teaches using a variety of
cross-linking agents. Like Gaylord and Ellis, Tanaka
teaches using a hydrophilic compound, including ethylene
glycol dimethacrylate, as a cross-linking agent. Tanaka
col. 8 ll. 2–6. But Tanaka also teaches, among other
things, that using hydrophobic siloxane-based compounds
are preferably employed as cross-linking agents because
of their ability to enhance oxygen permeability in the
resulting polymer. Tanaka col. 8 ll. 10–46.
     Tanaka differs from Gaylord in that, rather than us-
ing Tris, Tanaka teaches using a different siloxane-based
monomer, containing both hydrophobic alkylsiloxy ester
groups (siloxane-based groups) and internal hydrophilic
glycerol or polyether groups. See Tanaka col. 2 l. 64 –
col. 3 l. 5. Tanaka teaches that this replacement for Tris-
type monomers can be combined with MMA. See Tanaka
col. 2 l. 64 – col. 3 l. 5; col. 7 ll. 39–41. According to
Tanaka, this approach is more effective than using Tris-
type monomers because simply offsetting the hydrophobic
properties of Tris by copolymerizing it with hydrophilic
monomers can lead to an “opaque” product, “a fatal defect
for use as contact lens materials. Therefore, the polymer-
ization ratio of the hydrophilic monomer to the [Tris-type]
DOME PATENT L.P.   v. LEE                                7



monomer is limited to produce a transparent copoly-
mer . . . .” Tanaka col. 3 ll. 35–40; see also Tanaka
col. 3 ll. 6–34. Tanaka suggests that alternatively one
might reduce the number of siloxane-based molecules in
the polymer to reduce hydrophobicity, but then the oxy-
gen permeability of the resulting polymer becomes too
low. Tanaka col. 3 ll. 41–45. Tanaka explains that “[i]n
any case, there cannot be obtained a polymer suited for
preparing a contact lens which can be comfortably worn
continuously for a long period of time” when Tris-type
monomers are employed. Tanaka col. 3 ll. 48–51.
    In the district court action, Dome did not dispute that
the prior art disclosed the compounds recited in claim 1 of
the ’042 patent. The district court found that a person of
ordinary skill would have been motivated to combine the
prior art and that the prior art did not teach away from
the claimed invention, notwithstanding the disclosures in
Tanaka regarding Tris-type monomers. Additionally, the
court found that Dome’s proffered evidence of objective
indicia did not indicate nonobviousness. Accordingly, the
court agreed with the Board’s conclusion that claim 1 is
unpatentable as obvious under 35 U.S.C. § 103. Dome
appeals.      We have jurisdiction under 28 U.S.C.
§ 1295(a)(4)(C).
                            II
    Before reaching Dome’s appeal of the obviousness
conclusion, we first address Dome’s allegation that the
district court erred by only requiring the Patent Office to
show that claim 1 of the ’042 patent is obvious by a pre-
ponderance of the evidence, rather than by clear and
convincing evidence. We conclude that the district court
correctly applied the preponderance of the evidence
standard.
    Dome’s appeal arises from an ex parte reexamination
of the ’042 patent. Ordinarily, the Patent Office in such a
proceeding must establish by a preponderance of the
8                                      DOME PATENT L.P.   v. LEE



evidence that the reexamined claims are not patentable.
Rambus Inc. v. Rea, 731 F.3d 1248, 1255 (Fed. Cir. 2013).
If an ex parte reexamination results in the claims being
rejected as unpatentable, the decision can be appealed
directly to this court. See 35 U.S.C. § 141.
    Alternatively, for ex parte reexaminations filed before
November 29, 1999, a complaint can be filed in district
court against the Patent Office. See 37 C.F.R. § 1.303(a)
(2012); 35 U.S.C. § 145 (“The [district] court may adjudge
that such applicant is entitled to receive a patent for his
invention, . . . and such adjudication shall authorize the
Director to issue such patent . . . .”). “The thrust of such a
complaint is that the decision of the board is erroneous on
the facts, the law, or both. Indeed, the board’s decision is
the jurisdictional base for the suit. . . . [I]t is in essence a
suit to set aside the final decision of the board.” Fregeau
v. Mossinghoff, 776 F.2d 1034, 1036–37 (Fed. Cir. 1985).
    Accordingly, if the Patent Office decides after an ex
parte reexamination that a preponderance of the evidence
establishes the claimed subject matter is not patentable,
§ 145 authorizes the district court to review whether that
final decision is correct. The § 145 action in such a case
does not concern the different question of whether, as part
of a defense to an infringement action, clear and convinc-
ing evidence establishes that an issued and asserted
patent should be held invalid. See id. at 1037 (“it cannot
seriously be contended that a § 145 action is other than
one to overturn the board’s decision”).
    Citing 35 U.S.C. § 282 and Microsoft Corp. v. i4i Ltd.
Partnership, 131 S. Ct. 2238 (2011), Dome argues that the
district court erred by refusing to hold the Patent Office to
the clear and convincing evidence standard of proof.
According to Dome, the presumption of validity in § 282
applies to its claimed invention because the district court
action concerns a claim that the Patent Office previously
allowed to be patented. Accordingly, Dome argues the
DOME PATENT L.P.   v. LEE                                    9



Supreme Court’s holding that “§ 282 requires an invalidi-
ty defense to be proved by clear and convincing evidence,”
131 S. Ct. at 2242, also applies in Dome’s § 145 action.
    The § 145 action before the district court did not in-
volve a defense to a charge of infringement of an issued
patent. Section 282 therefore does not apply in this
instance. See 35 U.S.C. § 282. The district court here was
reviewing the Patent Office’s reexamination of claimed
subject matter, and its final determination that the
subject matter is not patentable, to ascertain whether
Dome was entitled to receive a patent. Only if the district
court found in favor of Dome would the Patent Office be
authorized to issue a patent. See 35 U.S.C. § 145. And
only after the patent issued would it be entitled to the
presumption of validity under § 282 and, consequently,
could not be held invalid absent clear and convincing
evidence.
    The clear and convincing evidence standard in the lit-
igation context “stems from our suggestion that the party
challenging a patent in court ‘bears the added burden of
overcoming the deference that is due to a qualified gov-
ernment agency presumed to have done its job.’” Sciele
Pharma Inc. v. Lupin Ltd., 684 F.3d 1253, 1260 (Fed. Cir.
2012) (quoting PharmaStem Therapeutics, Inc. v. ViaCell,
Inc., 491 F.3d 1342, 1366 (Fed. Cir. 2007)). But “[i]n
reexamination proceedings, ‘a preponderance of the
evidence must show nonpatentability before the [Patent
Office] may reject the claims of a patent application.’”
Rambus, 731 F.3d at 1255 (quoting Ethicon, Inc. v. Quigg,
849 F.2d 1422, 1427 (Fed. Cir. 1988)). This standard is
“substantially lower than in a civil case, . . . [and] there is
no presumption of validity.” In re Swanson, 540 F.3d
1368, 1377 (Fed. Cir. 2008) (citations omitted).
    “[A]n examiner is not attacking the validity of a pa-
tent, but is conducting a subjective examination of claims
in the light of prior art.” In re Etter, 756 F.2d 852, 857–58
10                                  DOME PATENT L.P.   v. LEE



(Fed. Cir. 1985); see also id. at 857 (“litigation and reex-
amination are distinct proceedings, with distinct parties,
purposes, procedures, and outcomes”). When the Patent
Office institutes ex parte reexamination, it reopens prose-
cution to determine whether the claimed subject matter
should have been allowed in the first place. At that point,
there is no need to presume that the Patent Office had
“done its job” in the previous examination. Accordingly,
the presumption of validity is no longer applicable.
    Our conclusion aligns with the purpose of the reexam-
ination process, which includes allowing the Patent Office
to take a second look at “patents thought ‘doubtful.’” In re
Etter, 756 F.2d at 857 (quoting H.R. Rep. No. 66-1307, at
3–4 (1980), reprinted in 1980 U.S.C.C.A.N. 6460, 6462).
“In a very real sense, the intent underlying reexamination
is to ‘start over’” in the Patent Office. Id. We would
hinder this intent if we required the district court here to
presume that the reexamined claim is valid because of the
Patent Office’s previous determination and, consequently,
to impose a burden to defend its own subsequent reexam-
ination decision by clear and convincing evidence. Thus,
the district court did not err by requiring the Patent
Office to show by a preponderance of the evidence that the
reexamined claim is obvious.
                            III
    We now address the district court’s obviousness de-
terminations. A patent may not issue “if the differences
between the subject matter sought to be patented and the
prior art are such that the subject matter as a whole
would have been obvious at the time the invention was
made to a person having ordinary skill in the art.” 35
U.S.C. § 103(a) (2006). 2 Obviousness is a question of law



     2   Because the application for the ’042 patent was
filed before March 16, 2013, the pre-Leahy-Smith America
DOME PATENT L.P.   v. LEE                                 11



based on underlying factual findings, including: “(1) the
scope and content of prior art; (2) differences between
prior art and claims; (3) the level of ordinary skill in the
art; and (4) objective indicia of nonobviousness.” Par
Pharm., Inc. v. TWI Pharm., Inc., 773 F.3d 1186, 1193
(Fed. Cir. 2014) (citing Graham v. John Deere Co., 383
U.S. 1, 17–18 (1966)). We review the ultimate conclusion
of obviousness de novo and the underlying factual find-
ings for clear error. Medichem, S.A. v. Rolabo, S.L., 437
F.3d 1157, 1164 (Fed. Cir. 2006).
                             A
    If all elements of a claim are found in the prior art, as
is the case here, the factfinder must further consider the
factual questions of whether a person of ordinary skill in
the art would be motivated to combine those references,
and whether in making that combination, a person of
ordinary skill would have had a reasonable expectation of
success. Id. at 1164. The Supreme Court has cautioned,
however, that an obviousness determination cannot be
confined by formalistic rules. KSR Int’l Co. v. Teleflex
Inc., 550 U.S. 398, 419 (2007). Rather, courts must take
an “expansive and flexible approach” to the question of
obviousness. Id. at 415.
    Evidence of a motivation to combine prior art refer-
ences may flow from “‘the nature of the problem to be
solved.’” Tokai Corp. v. Easton Enters., Inc., 632 F.3d
1358, 1371 (Fed. Cir. 2011) (quoting Ruiz v. A.B. Chance
Co., 357 F.3d 1270, 1276 (Fed. Cir. 2004)). Here, the
record supports the district court’s finding that a person
of ordinary skill understood that high oxygen permeabil-
ity in contact-lens materials was desirable. And this
understanding would have motivated a person of ordinary



Invents Act, Pub. L. No. 112-29, 125 Stat. 284 (2011),
version of 35 U.S.C. § 103 applies.
12                                   DOME PATENT L.P.   v. LEE



skill to combine the Tris monomer disclosed in Gaylord
with the Tris-type cross-linking agent disclosed in Tanaka
to increase the oxygen permeability of a contact lens.
     Gaylord, for example, teaches that the previously
used contact-lens material, PMMA, is rigid and durable
but relatively impermeable to oxygen. Gaylord col. 1
ll. 24–30. Gaylord explained it would be “highly desira-
ble” to provide a contact-lens material that has “increased
oxygen permeability, is wettable,” and has improved
mechanical properties. Gaylord col. 1 ll. 39–44. To meet
that need, Gaylord discloses using siloxane-based com-
pounds, including Tris-type monomers. See Gaylord col. 1
ll. 44–51; col. 2 ll. 32–44. Similarly, Ellis teaches that
oxygen permeability is “directly related” to the silicone
content in contact lenses. Ellis col. 1 ll. 29–30. And
Tanaka explains that contact lenses with poor oxygen
permeability would make it “impossible to wear them
continuously for a long period of time.” Tanaka col. 1 ll.
30–32. Tanaka therefore “preferably employed” siloxane-
based cross-linking agents, including some that are
hydrophobic, because the oxygen permeabilities of the
obtained cross-linked copolymers are high. Tanaka col. 8
ll. 10–46.
    The testimonies from Dome’s experts also support the
district court’s conclusion. Dr. Mark Melamed testified
that “it’s essential that there be an adequate flow of
oxygen either through the lens or around the lens.” J.A.
1805; see also J.A. 1804–05 (“it’s essential that there be a
constant flow of oxygen to the entry surface of the cornea
in order for a contact lens to be worn safely for a period of
time”). A “chief” issue during Dr. Melamed’s practice was
“the ability to get oxygen across a contact lens,” while
“maintaining a nice even tear film over the contact lens
and over the cornea,” i.e., hydrophilicity, was considered a
“secondary problem” related to contact lens comfort levels.
J.A. 1807. And another of Dome’s experts, Dr. Timothy
Long, testified that those in the field were turning to
DOME PATENT L.P.   v. LEE                                 13



siloxane-based compounds to enhance a polymer’s oxygen
permeability. See J.A. 1746 (“It has great oxygen perme-
ability. It’s one of the big driving forces for people in the
contact lens field to use it.”). Accordingly, the district
court did not clearly err in finding that the evidence
disclosed a motivation to combine the prior art.
                             B
    Dome argues that a person of ordinary skill would not
have been motivated to combine Gaylord with Tanaka
because the prior art teaches away from using Tris with
siloxane-based cross-linking agents. To improve Gay-
lord’s disclosures, Dome asserts, a person of ordinary skill
would have been inclined to introduce hydrophilic cross-
linking agents, instead of hydrophobic siloxane-based
cross-linking agents, to offset the hydrophobicity of Tris,
but Tanaka warned against this approach. As an alterna-
tive, Tanaka suggested designing a new amphiphilic or
hydrophilic monomer to replace Tris altogether.
    “[W]hen the prior art teaches away from combining
certain known elements, discovery of a successful means
of combining them is more likely to be nonobvious.” KSR,
550 U.S. at 416. A reference teaches away from a claimed
invention when a person of ordinary skill, “upon reading
the reference, would be discouraged from following the
path set out in the reference, or would be led in a direc-
tion divergent from the path that was taken by the appli-
cant.” In re Gurley, 27 F.3d 551, 553 (Fed. Cir. 1994).
But “[t]he degree of teaching away will of course depend
on the particular facts.” Id.; see also id. (“A known or
obvious composition does not become patentable simply
because it has been described as somewhat inferior to
some other product for the same use.”). And “there is no
rule that a single reference that teaches away will man-
date a finding of nonobviousness.” Medichem, 437 F.3d at
1165; see also KSR, 550 U.S. at 421 (“Rigid preventative
rules that deny factfinders recourse to common sense . . .
14                                        DOME PATENT L.P.    v. LEE



are neither necessary under our case law nor consistent
with it.”). Additionally, just because “better alternatives”
may exist in the prior art “does not mean that an inferior
combination is inapt for obviousness purposes.” In re
Mouttet, 686 F.3d 1322, 1334 (Fed. Cir. 2012) (citing
Gurley, 27 F.3d at 553).
    Here, Tanaka discloses potential disadvantages asso-
ciated with using Tris-type monomers. It explains that,
outside of certain unspecified limits, if hydrophilic mono-
mers are copolymerized with hydrophobic Tris-type
monomers to offset hydrophobicity, the copolymer “is
liable to become opaque.” Tanaka col. 3 ll. 6–36. Tanaka
explains that opacity is a “fatal defect” for the copolymer’s
use as a material for contact lenses, and thus offsetting
hydrophobic Tris-type monomers with hydrophilic mono-
mers “is limited.” Tanaka col. 3 ll. 36–41. Tanaka does
not further identify the mentioned limits, but it goes on to
disclose an alternative for Tris-type monomers. See
Tanaka col. 3 ll. 52–59.
    The record, however, supports the district court’s find-
ing that other prior art references disclose roadmaps on
how to offset the disadvantages associated with using
Tris-type monomers to obtain a material suitable for
contact lenses.
     Ellis acknowledges that “[i]t has been difficult to ob-
tain high oxygen permeability while still maintaining
other properties . . . when oxygen permeability is derived
from the silicone content” in a polymer. Ellis col. 1 ll. 30–
34. Ellis then teaches how to effectively overcome this
difficulty without compromising the resulting material’s
clarity. Ellis teaches several examples of using Tris with
hydrophilic monomers in varying concentrations and
concludes that “[i]n all cases, the polymers are optically
clear and meet required standards of contact lenses.”
Ellis col. 7 ll. 15–17; see also id. col. 5 l. 50 – col. 7 l. 13; id.
col. 7 ll. 19–21. Ellis also discloses that “many variations
DOME PATENT L.P.   v. LEE                                  15



are possible within the scope of keeping the physical
properties,” stating that “[f]or example, two or more
siloxanyl alkyl ester monomers can be used instead of a
single such monomer for that component of the system.”
Ellis col. 7 ll. 30–36.
     Gaylord similarly acknowledges the issues identified
by Tanaka and then sets out a solution, one that does not
compromise the resulting polymer’s use as a material for
contact lenses. Gaylord teaches that “[w]hile some of the
copolymers are inherently wettable by human tears, it
may be necessary to improve the wettability of others.”
Gaylord col. 5 ll. 39–41. For example, “wettability can be
imparted to the copolymer by the addition of from about
0.1% to about 10% by weight of one or more hydrophilic
monomers to the copolymerization mixture” or by other
treatments, including corona discharge, oxidizing, or
soaking in aqueous solutions. Id. col. 5 ll. 42–58. Gaylord
also lists examples “illustrat[ing] the preparation and
properties of copolymers containing varying proportions of
a siloxanyl monomer, [MMA], and a hydrophilic monomer
(hydroxyethyl methacrylate).” Gaylord col. 9 l. 67 –
col. 10 l. 2. Many of these examples resulted in “trans-
parent” materials. See Ellis col. 9 l. 66 – col. 10 l. 24.
    The district court found that while Tanaka warns that
constructing a lens with Tris-type materials can be diffi-
cult, the other two references plainly teach that Tris could
be used effectively to make contact lenses. Accordingly,
the district court concluded that a person of ordinary skill
would not have been dissuaded from combining the prior
art, particularly in light of Gaylord and Ellis. The record
supports these factual findings.
    While Dome’s argument that the claimed subject mat-
ter would not have been obvious in light of Tanaka’s
disclosures is plausible, “[t]he burden of overcoming the
district court’s factual findings is, as it should be, a heavy
one.” Polaroid Corp. v. Eastman Kodak Co., 789 F.2d
16                                    DOME PATENT L.P.   v. LEE



1556, 1559 (Fed. Cir. 1986). Our standard of review
requires that we uphold the district court’s factual find-
ings on this point, rather than revisiting them de novo. In
this case, the district court did not clearly err in finding a
person of ordinary skill would have been motivated to
combine the identified prior art to arrive at the claimed
invention, notwithstanding Tanaka’s disclosures regard-
ing Tris-type compounds.
                              C
    Dome also challenges the district court’s handling of
evidence relating to objective indicia of nonobviousness.
Dome argues first that the district court erred by improp-
erly shifting the burden onto Dome to prove nonobvious-
ness once the Patent Office established a prima facie case
of obviousness.
    While we have held that a district court has erred “by
making its finding that the patents in suit were obvious
before it considered the objective considerations and by
shifting the burden of persuasion to [the patentee],” In re
Cyclobenzaprine Hydrochloride Extended-Release Capsule
Patent Litig., 676 F.3d 1063, 1075 (Fed. Cir. 2012), the
legal framework used by the district court in this case was
not improper.
    Before reaching its ultimate conclusion of obvious-
ness, the district court first considered whether the Pa-
tent Office had demonstrated that a person of ordinary
skill would have been motivated to combine the com-
pounds recited in claim 1 of the ’042 patent and that there
would have been a reasonable expectation of success. The
court also considered whether the prior art taught away
from the claimed invention. After finding in favor of the
Patent Office on these points, the court agreed with Dome
that a product, the Boston IV contact lens, embodies claim
1 of the ’042 patent and that the Boston IV contact lens
achieved some commercial success. Nevertheless, the
court found that the evidence relating to the Boston IV
DOME PATENT L.P.   v. LEE                               17



contact lens was not particularly strong. Next, after
considering the parties’ arguments and making the rele-
vant findings of fact, the court concluded that claim 1 of
the ’042 patent is obvious as a matter of law. Indeed, the
court’s opinion, when read as a whole, shows that the
court considered and made factual findings on all evi-
dence relating to objective indicia before reaching its
ultimate conclusion on obviousness.
    Dome also argues that the district court erred by re-
fusing to consider Dome’s proffer of evidence relating to
objective indicia of nonobviousness. We have consistently
stated that “all evidence pertaining to the objective indi-
cia of nonobviousness must be considered before reaching
an obviousness conclusion.” Plantronics, Inc. v. Aliph,
Inc.,724 F.3d 1343, 1355 (Fed. Cir. 2013). The district
court here did not refuse to consider Dome’s evidence.
Rather, the court found that Dome was entitled to a
presumption that the commercial success of the Boston IV
contact lens relates to the claimed invention. Nonethe-
less, the court found that the evidence was “not particu-
larly strong.” J.A. 57. The court also gave “little weight”
to testimony relating to the reasons for the Boston IV
contact lens’s commercial success. J.A. 6 n.4. Moreover,
the court found that Dome’s own expert testified that the
commercial success of the Boston IV contact lens was in
part due to other economic and commercial factors not
related to the allegedly novel aspects of the claimed
invention. Dome does not challenge these findings.
    After having accepted all evidence relating to the four
Graham factors—including evidence relating to commer-
cial success—the district weighed the evidence and then
made findings of fact. Only after considering all of the
evidence did the court reach its obviousness conclusion.
Thus, we conclude that the court did not err in its consid-
eration of the evidence relating to objective indicia of
nonobviousness.
18                                 DOME PATENT L.P.   v. LEE



                           IV
    We have considered Dome’s remaining arguments and
find them unpersuasive. Because the district court did
not commit reversible error in its determination that the
claimed subject matter would have been obvious to a
person of ordinary skill during the relevant time period,
we affirm.
                      AFFIRMED
