  United States Court of Appeals
      for the Federal Circuit
                 ______________________

        IN RE: GLOBAL IP HOLDINGS LLC,
                      Appellant
               ______________________

                       2018-1426
                 ______________________

    Appeal from the United States Patent and Trademark
Office, Patent Trial and Appeal Board in No. 14/632,238.
                  ______________________

                  Decided: July 5, 2019
                 ______________________

    FRANK A. ANGILERI, Brooks Kushman PC, Southfield,
MI, argued for appellant. Also represented by ROBERT C.J.
TUTTLE.

   KAKOLI CAPRIHAN, Office of the Solicitor, United States
Patent and Trademark Office, Alexandria, VA, argued for
appellee Andrei Iancu. Also represented by THOMAS W.
KRAUSE, SARAH E. CRAVEN.
                ______________________

    Before MOORE, REYNA, and STOLL, Circuit Judges.
STOLL, Circuit Judge.
     Global IP Holdings, LLC appeals the Patent Trial and
Appeal Board’s decision affirming the examiner’s rejection
of its reissue claims for failure to comply with the written
description requirement. Because the legal standard ap-
plied by the Board conflicts with our precedent, we vacate
2                            IN RE: GLOBAL IP HOLDINGS LLC



the Board’s decision and remand for further proceedings
consistent with this opinion.
                       BACKGROUND
    Global owns U.S. Patent No. 8,690,233, which claims
carpeted automotive vehicle load floors having sandwich-
type composite panels with cellular cores. In one embodi-
ment, the load floor refers to the back-side of a car seat,
which operates as the trunk floor when folded down. See
’233 patent, Fig. 5. Figure 6 of the ’233 patent shows the
composition of the claimed load floor:




The specification discloses that hinged panel 10 is typically
manufactured from a stack of material including “first and
second reinforced thermoplastic skins 16 and 18, respec-
tively, a thermoplastic cellular core 20 disposed between
the skins 16 and 18 and a top layer of a substantially con-
tinuous covering layer generally indicated at 21.” Id.
at col. 4 ll. 35–42.
     Global filed a reissue application, seeking to broaden
its claims in the ’233 patent. In particular, it replaced the
term “thermoplastic” with “plastic” in independent claims
IN RE: GLOBAL IP HOLDINGS LLC                                3


1, 14, and 17. Global’s reissue claim 1 is representative
and reproduced below, with strikeouts indicating the dele-
tions made to the original claim:
    1. A carpeted automotive vehicle load floor com-
    prising:
    a composite panel having first and second rein-
    forced thermoplastic skins and a thermoplastic cel-
    lular core disposed between and bonded to the
    skins, the first skin having a top surface;
    a cover having top and bottom surfaces and spaced
    apart from the composite panel; and
    a substantially continuous top covering layer
    bonded to the top surface of the panel and the top
    surface of the cover to at least partially form a car-
    peted load floor having a carpeted cover, wherein
    an intermediate portion of the top covering layer
    between the cover and the panel is not bonded to
    either the panel or the cover to form a living hinge
    which allows the carpeted cover to pivot between
    different use positions relative to the rest of the
    load floor.
J.A. 40.
    The Patent Office’s rules for reissue applications re-
quire an inventor oath or declaration specifically identify-
ing the error relied on as the basis for the reissue.
37 C.F.R. § 1.175. Here, inventor Darius J. Preisler filed a
declaration explaining that he is the inventor of over fifty
U.S. patents in the field of plastic-molded products and
that, at the time of the invention, he was aware of the use
of plastics other than thermoplastics for the formation of a
sandwich-type composite panel with a cellular core. See
J.A. 213–20 ¶¶ 5–26. He also cited patents and patent ap-
plications, including his own, as well as technical papers
purportedly disclosing the use of thermoset plastics
4                              IN RE: GLOBAL IP HOLDINGS LLC



(instead of thermoplastics) in vehicle load floors.         See
J.A. 216–220 ¶¶ 8–26.
     The examiner rejected Global’s reissue claims 1–21 for
failing to comply with the written description requirement
of 35 U.S.C. § 112, first paragraph. See J.A. 366–67. The
examiner noted that “the specification indicates that the
first and second skins and core are only described as being
formed from thermoplastic materials and are not described
as being formed generally from plastic materials.” J.A. 367
(citing ’233 patent col. 1 ll. 25–28, col. 2 ll. 30–32, 59–60,
col. 3 ll. 3–6, 28–29, col. 4 ll. 35–40, 42–45, col. 5 ll. 9–14,
19–21, 37–39). After finding that “the specification only
supports thermoplastics,” the examiner determined that
Global “cannot claim the full range of plastics, which would
include thermosetting as well as thermoplastics.” Id. Ac-
cording to the examiner, by changing the term “thermo-
plastic” to “plastic,” Global introduced new matter. See id.
     The Board affirmed the examiner’s rejection of reissue
claims 1–21 under § 112, first paragraph. Ex Parte Preis-
ler, No. 2018-000871, 2017 WL 6882664, at *1 (P.T.A.B.
Dec. 29, 2017) (“Decision”). Global argued before the Board
that, because the type of plastic used is not critical to the
invention and plastics other than thermoplastics were pre-
dictable options, the disclosure of thermoplastics (species)
supports the claiming of plastics (genus). See id. at *2–3.
Global also cited the inventor declaration, see id. at *2,
which explained that multiple types of plastics other than
thermoplastics were known for use in automotive load
floors and that the specific type of plastic from which the
skins and core of the panels are fabricated is not critical to
the claimed invention. See J.A. 217–20 ¶¶ 15, 21, 24–26,
28. The Board rejected Global’s arguments. It agreed with
the examiner that the specification only describes the skins
and core of the claimed load floor as being formed from
thermoplastic materials. See Decision, 2017 WL 6882664,
at *3. The Board explained that “regardless of the predict-
ability of results of substituting alternatives, or the actual
IN RE: GLOBAL IP HOLDINGS LLC                                5


criticality of thermoplastics in the overall invention,
[Global’s] Specification, as a whole, indicates to one skilled
in the art that the inventors had possession only of the
skins and core comprising specifically thermoplastic.” Id.
    Global appeals the Board’s decision. We have jurisdic-
tion pursuant to 28 U.S.C. § 1295(a)(4)(A).
                        DISCUSSION
    We review the Board’s legal conclusions de novo and its
fact findings for substantial evidence. Belden Inc. v. Berk-
Tek LLC, 805 F.3d 1064, 1073 (Fed. Cir. 2015). A finding
is supported by substantial evidence if a reasonable mind
might accept the evidence as sufficient to support the find-
ing. See Consol. Edison Co. v. NLRB, 305 U.S. 197, 229
(1938).
    Section 112 of the patent statute provides in relevant
part:
    The specification shall contain a written descrip-
    tion of the invention, and of the manner and pro-
    cess of making and using it, in such full, clear,
    concise, and exact terms as to enable any person
    skilled in the art to which it pertains, or with which
    it is most nearly connected, to make and use the
    same . . . .
35 U.S.C. § 112, ¶ 1 (2006). 1 This written description re-
quirement is met when the specification clearly allows



    1    Paragraph 1 of 35 U.S.C. § 112 was replaced with
newly designated § 112(a) by section 4(c) of the Leahy-
Smith America Invents Act (“AIA”), Pub. L. No. 112–29,
sec. 4(c), 125 Stat. 284, 296 (2011). Section 4(e) of the AIA
applied that change “to any patent application that is filed
on or after” September 16, 2012. Id. sec. 4(e), 125 Stat.
at 297. Because the application resulting in the ’233 patent
6                              IN RE: GLOBAL IP HOLDINGS LLC



persons of ordinary skill to recognize that the inventor “in-
vented what is claimed.” Ariad Pharm., Inc. v. Eli Lilly &
Co., 598 F.3d 1336, 1351 (Fed. Cir. 2010) (en banc) (quot-
ing Vas–Cath Inc. v. Mahurkar, 935 F.2d 1555, 1563
(Fed. Cir. 1991)). In other words, the test for sufficiency is
whether the specification “reasonably conveys to those
skilled in the art that the inventor had possession of the
claimed subject matter as of the filing date.” Id. This test
involves an inquiry into the four corners of the specification
from the perspective of a person of ordinary skill. Id. De-
termining whether a patent complies with the written de-
scription requirement is a question of fact that necessarily
varies depending on the context. Id. “[T]he level of detail
required to satisfy the written description requirement
varies depending on the nature and scope of the claims and
on the complexity and predictability of the relevant tech-
nology.” Id.
     We hold that the Board legally erred in its analysis of
whether the ’233 patent complies with the written descrip-
tion requirement under § 112, first paragraph. The Board
found that the ’233 patent’s specification was insufficient
“regardless of the predictability of results of substituting al-
ternatives, or the actual criticality of thermoplastics in the
overall invention.” Decision, 2017 WL 6882664, at *3 (em-
phasis added). This statement conflicts with Ariad, which
instructs that “the level of detail required to satisfy the
written description requirement varies depending on the
nature and scope of the claims and on the complexity and
predictability of the relevant technology.” 598 F.3d at 1351
(emphasis added). Contrary to the Board’s statement, the
predictability of substituting generic plastics for thermo-
plastics in the skins and cellular cores of vehicle load floors
is relevant to the written description inquiry.



was filed before that date, we refer to the pre-AIA version
of § 112.
IN RE: GLOBAL IP HOLDINGS LLC                                7


     In addition to predictability, we have held that the crit-
icality or importance of an unclaimed limitation to the in-
vention can be relevant to the written description inquiry.
See In re Peters, 723 F.2d 891, 893–94 (Fed. Cir. 1983). In
Peters, the original claims required, among other things, a
metal tip having a tapered shape. Id. at 892. The patent
owner filed a reissue application seeking to broaden the
claims to cover both tapered and non-tapered tips. Id. The
Board held that the broadened claims sought by the reissue
application were not supported by the original disclosure
because the only tips disclosed were tapered. Id. at 893.
We disagreed, holding that “[t]he broadened claims merely
omit an unnecessary limitation that had restricted one el-
ement of the invention to the exact and non-critical shape
disclosed in the original patent.” Id. We reasoned that the
disclosed tip configuration was not critical because no prior
art was overcome based on the tip shape and “one skilled
in the art would readily understand that in practicing the
invention it is unimportant whether the tips are tapered.”
Id.
    We see nothing in Ariad rejecting the analysis in Pe-
ters. In Ariad, we identified a number of factors that bear
on whether a written description disclosing a species sup-
ports generic claims, including “the existing knowledge in
a particular field, the extent and content of the prior art,
the maturity of the science or technology, [and] the predict-
ability of the aspect at issue.” Ariad, 598 F.3d at 1351
(quoting Capon v. Eshhar, 418 F.3d 1349, 1359 (Fed. Cir.
2005)). Ariad did not present an exhaustive list of relevant
factors, and we hold that, in some cases, the criticality or
importance of the expressly disclosed species may be rele-
vant to whether an inventor had possession of a claimed
genus.
    Global requests that we reverse, arguing that “there is
no evidence in the record to support any finding that the
‘plastic’ limitation is critical.” Appellant Br. 12. We de-
cline to decide this factual question in the first instance.
8                            IN RE: GLOBAL IP HOLDINGS LLC



We thus vacate the Board’s decision. On remand, the
Board should address the relevant factors, including pre-
dictability and criticality, based on the record evidence and
determine whether the written description requirement
has been satisfied under the proper legal standard.
             VACATED AND REMANDED
                           COSTS
    Costs to Appellant.
