  United States Court of Appeals
      for the Federal Circuit
                ______________________

REGENTS OF THE UNIVERSITY OF MINNESOTA,
             Plaintiff-Appellant,
                           v.
          AGA MEDICAL CORPORATION,
               Defendant-Appellee.
                ______________________

                      2012-1167
                ______________________

    Appeal from the United States District Court for the
District of Minnesota in No. 07-CV-4732, Judge Patrick J.
Schiltz.
                 ______________________

                 Decided: June 3, 2013
                ______________________

    KEVIN D. CONNEELY, Leonard, Street and Deinard
Professional Association, of Minneapolis, Minnesota,
argued for the plaintiff-appellant. With him on the brief
were DAVID D. AXTELL, RUTH A. RIVARD and KATHERINE A.
MOERKE.

    J. DEREK VANDENBURGH, Carlson, Caspers, Vanden-
burgh, Lindquist & Schuman, P.A., of Minneapolis, Min-
nesota, argued for defendant-appellee. With him on the
brief were ALAN G. CARLSON, R.J. ZAYED, and TARA C.
NORGARD.
                 ______________________
2                      REGENTS UNIV OF MINN   v. AGA MEDICAL


    Before RADER, Chief Judge, and DYK and WALLACH,
                     Circuit Judges.
DYK, Circuit Judge.
    Appellant Regents of the University of Minnesota
(“the University”) owns U.S. Patent No. 6,077,281 (“the
’281 patent”) and U.S. Patent No. 6,077,291 (“the ’291
patent”), which are directed to medical devices for repair-
ing heart defects. The University accused AGA Medical
Corporation (“AGA”) of infringing both patents. After
claim construction, the district court granted summary
judgment that the ’291 patent was not infringed and that
the asserted claims of the ’281 patent were invalid as
anticipated. The University appeals, arguing that the
district court erred in its construction of the claims of the
’291 patent, and in finding the ’281 patent anticipated by
a prior art device. We affirm.
                       BACKGROUND
    The ’291 and ’281 patents are directed toward “septal
occluders,” which are medical devices used to block holes
in a thin wall of muscle and tissue (a “septum”) dividing
two chambers of the heart. “Transcatheter” septal oc-
cluders can be delivered to the heart and positioned in a
septal defect using a catheter threaded through a vein. In
1975, King and Mills received a patent on the first
transcatheter septal occluder (“the King device”). U.S.
Pat. No. 3,874,388 (filed Feb. 12, 1973).
    In 1992, the University filed Patent Application No.
07/822,951 (“the ’951 application”) claiming a transcathe-
ter septal occluder invented by Dr. Gladwin Das. Four
patents eventually issued from successive divisions of the
’951 application, including U.S. Patent No. 5,334,217 (“the
’217 patent”), issued in April 1994, another patent not at
issue here, and the ’291 and ’281 patents, which were both
issued in June 2000. The patents have different claims,
 REGENTS UNIV OF MINN   v. AGA MEDICAL                    3
but generally share the same specification. The “Sum-
mary of the Invention” explains that the claimed device
has “first and second occluding disks which are attached
to one another” centrally. ’291 patent col. 3 ll. 7–8; ’281
patent col. 3 ll. 11–12. Each disk comprises a membrane
and a frame, and can be “collapsed” to fit in a catheter.
’291 patent col. 3 ll. 8–12. The device is delivered through
the catheter to the heart, where it is positioned with one
disk on each side of the defective septum. As the catheter
is withdrawn, the disks expand, covering both sides of the
defective septum and blocking the hole. See id. at col. 3 ll.
10–14. The patents’ shared specification acknowledges
prior art septal occluders with expandable membranes,
including the patented King device and a device described
in an article by Dr. James Lock (“the Lock device”). The
Lock and King devices both have “umbrella-like” struc-
tures mounted on radial frames. The specification of the
patents-in-suit disparages prior art radial frame devices
as “mechanically complex and requir[ing] a great deal of
remote manipulation for deployment,” ’291 patent col. 2 ll.
44–45; ’281 patent col. 2 ll. 48–49, and because the “single
point or pivot” connecting the two umbrella structures can
drift within the septal defect, allowing the device to
become decentered. ’291 patent col. 2 ll. 52–56; ’281
patent col. 2 ll. 56–60.
    In 2007, the University filed suit against AGA, alleg-
ing infringement of the ’291 and ’281 patents. AGA’s
accused septal occluders are one-piece devices made from
tubes of wire mesh. The mesh is molded into a preset
shape with two large flat regions separated by a narrow
waist. The device can be compressed into an elongated
shape to fit in a catheter. Upon deployment from the
catheter inside the heart, the device spontaneously
springs back to the preset shape and blocks the septal
defect.
   At the parties’ request, the district court held a
Markman hearing and construed various disputed terms
4                      REGENTS UNIV OF MINN   v. AGA MEDICAL
in the ’291 and ’281 patents. See Regents of the Univ. of
Minn. v. AGA Med. Corp., 660 F. Supp. 2d 1037 (D. Minn.
2009). In January 2011, the court partially granted
AGA’s motion for summary judgment of non-
infringement, ruling that no reasonable jury could find
that AGA’s one-piece mesh device infringed the ’291
patent. Regents of the Univ. of Minn. v. AGA Med. Corp.,
No. 07-CV-4732, 2011 WL 13943, at *9, *15–16 (D. Minn.
Jan. 4, 2011). In December 2011, the court granted AGA’s
motion for summary judgment of invalidity with respect
to asserted claims 1, 4, and 5 of the ’281 patent, Regents of
the Univ. of Minn. v. AGA Med. Corp., 835 F. Supp. 2d
711 (D. Minn. 2011), finding that all three claims were
anticipated by the prior art Lock device, id. at 723–26. 1
The district court dismissed AGA’s remaining counter-
claims as moot. Id. at 713–14. 2 The University timely
appealed, and we have jurisdiction pursuant to 28 U.S.C.
§ 1295(a)(1). Although the patents in this case are relat-


    1   AGA had also requested ex parte reexamination of
claims 1, 4 and 5 of the ’281 patent. In 2011, the Patent
and Trademark Office (“PTO”) examiner issued a final
office action rejecting all three claims as anticipated by
King and Lock. See Office Action in Ex Parte Reexamina-
tion, No. 90/011,290 (PTO June 27, 2011). An appeal of
the final office action is pending before the Patent Trial
and Appeal Board. See Order Withdrawing Remand and
Re-Docketing Appeal, PTAB Appeal No. 2012-010628
(PTAB Dec. 7, 2012).
    2   The district court also determined that the ’281
patent was invalid because claim 1, the only independent
claim, was indefinite. Regents, 835 F. Supp. 2d at 730–31.
Because we agree that the asserted claims of the ’281
patent are invalid as anticipated, we do not reach the
question of indefiniteness.
 REGENTS UNIV OF MINN   v. AGA MEDICAL                  5
ed, they present distinct legal issues on appeal, so we
discuss them separately.
                        DISCUSSION
                    I. The ’291 Patent
                  A. Claim construction
    The dispute as to the ’291 patent turns almost entire-
ly on claim construction. Claim construction is a question
of law, Markman v. Westview Instruments, Inc., 52 F.3d
967, 976–80 (Fed. Cir. 1995) (en banc), aff’d, 517 U.S. 370
(1996), which we review without deference, Cybor Corp. v.
FAS Techs., Inc., 138 F.3d 1448, 1454–55 (Fed. Cir. 1998)
(en banc).
    Representative claim 1 of the ’291 patent describes a
septal occluder with two occluding disks “affixed” to one
another at their centers, to “define a conjoint disk”:
   1. A septal defect closure device comprising first
   and second occluding disks, each disk comprising
   a flexible, biologically compatible membrane ca-
   pable of being collapsed for passage through a
   catheter and elastically returning to a predeter-
   mined shape for tautly holding a portion of the
   membrane against a septum; a central portion of
   the membrane of the first disk being affixed to a
   central portion of the membrane of the second disk
   to define a conjoint disk . . . .
’291 patent col. 17 ll. 54–61 (emphases added).
     As shown in Figures 3 and 4, a preferred embodiment
of the claimed invention comprises two membrane disks
(20, 30), each having a jointed pentagonal frame (24)
“attached to and desirably extend[ing] substantially
around the periphery of the membrane.” ’291 patent col.
5 ll. 5–6. The flexible frames can be compressed to allow
the device to pass through a catheter for delivery to the
heart. As the catheter is withdrawn and the device is
6                      REGENTS UNIV OF MINN   v. AGA MEDICAL
released, the frames expand to pull the membrane disks
taut. Figure 3 depicts a side view of the device with the
two membrane disks fully expanded (22, 32) and the
smaller “conjoint disk” (40) between them:




’291 patent figs. 3,4. Figure 4 illustrates how, in this
preferred embodiment, the two membrane disks are
“sewn to one another . . . with the stitching defining the
shape and size of the conjoint disk” (40). ’291 patent col. 7
ll. 55–57. An appropriately sized conjoint disk is posi-
tioned inside the septal defect, while the expanded frames
(which are larger than the defect) rest against either side
of the septum to hold the device in place.
    With respect to the ’291 patent, one issue of claim
construction is disputed on appeal: whether the district
court correctly construed the patent to require two dis-
crete disks. All independent claims of the ’291 patent
relate to a device with “first and second disks” or “first
and second occluding disks.” Regents, 660 F. Supp. 2d at
1042. The two disks are described as “affixed” (claims 1,
 REGENTS UNIV OF MINN   v. AGA MEDICAL                    7
4, 23, 24, 30), “joined” (claims 17, 24, 25), or “connected”
(claim 28) to one another, forming a “conjoint” structure
(claims 1–5, 9, 11, 12, 14, 15, 23, 25–27). As the district
court noted, “[t]he parties . . . agreed to treat the terms
‘affixed,’ ‘joined,’ and ‘connected’ as essentially synony-
mous.” Id. at 1041. Nor does either party dispute that
throughout the ’291 patent, the term “conjoint” is used to
denote the affixed, joined, or connected portions of the
disks. The district court concluded that “a person of
ordinary skill in the art . . . would read the ’291 patent as
covering only a device made up of two physically separate
disks that are attached to one another,” and therefore
construed the phrase “first and second [occluding] disks”
to mean “physically distinct and separate disks.” Id. at
1045. The court reasoned that “one does not ordinarily
speak of the parts of a unitary structure as being ‘affixed’
or ‘joined’ or ‘connected’ to each other,” id. at 1044, and
concluded that this “clear implication . . . should be made
explicit” in its claim construction by requiring that the
disks had been originally separate, id. at 1043. The court
“reached this decision in part based on how the phrase
‘conjoint disk’ is used throughout the patent,” that is, to
describe a structure formed by affixing, joining, or con-
necting the two disks. Id. at 1044; see also id. at 1056. A
subsequent order elaborated that “[t]he word ‘disks’ in the
phrases ‘first and second occluding disks’ and ‘first and
second disks’ means ‘disks that, before being affixed,
joined, or connected, exist separately as individual, physi-
cally distinct disks.’” Regents, 2011 WL 13943, at *2. It is
undisputed that this construction excludes AGA’s device,
which is molded from a single tubular piece of mesh.
    On appeal, the University argues that the district
court’s construction improperly imported limitations from
outside the claims, and is unsupported by the specifica-
tion or prosecution history. We disagree.
   The claim language fully supports a requirement of
separateness. Independent claim 1 explains that the
8                      REGENTS UNIV OF MINN   v. AGA MEDICAL
“conjoint disk” is formed by “affix[ing]” the membranes of
the “first and second occluding disks” to one another. ’291
patent col. 17 ll. 54–64. Dependent method claim 23
describes the occluder as having “a central portion of the
flexible structure of the first disk being affixed directly to
a central portion of the flexible structure of the second
disk to define [a] conjoint disk.” Id. at col. 19 ll. 16–19.
Both dependent claims 11 and 12 describe a “conjoint
disk” “compris[ing] a piece of another material disposed
between the first and second disks,” further supporting
the conclusion that the two disks must be discrete struc-
tures. 3 Id. at col. 18 ll. 23–29.
    The separateness requirement is also fully supported
by the specification, which is “the single best guide to the
meaning of a disputed term.” Phillips v. AWH Corp., 415
F.3d 1303, 1315 (Fed. Cir. 2005) (en banc) (quoting Vitri-
onics Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1582 (Fed.
Cir. 1996)). The ’291 specification never teaches an
embodiment constructed as a single piece. Quite the
opposite: “every single embodiment disclosed in the ’291
patent’s drawings and its written description is made up
of two separate disks.” Regents, 660 F. Supp. 2d at 1044.
The ’291 patent explains that
    [t]he present invention provides a simple, reliable
    device for effectively occluding a septal defect. The
    instant closure device includes first and second
    occluding disks which are attached to one another.
    . . . A central portion of the membrane of each disk
    is affixed to a corresponding portion of the mem-


    3   Although the University suggests that language
in unasserted claims is not relevant, our precedent estab-
lishes that “both asserted and unasserted” claims are
valuable to “illuminate the meaning of the same term in
other claims.” Phillips v. AWH Corp., 415 F.3d 1303,
1314 (Fed. Cir. 2005) (en banc).
 REGENTS UNIV OF MINN    v. AGA MEDICAL                       9
    brane of the other disk, thereby attaching the two
    disks directly to one another at their centers. The
    affixed central portion of the two membranes de-
    fine[] a central “conjoint disk” of the device . . . .
’291 patent col. 3 ll. 5–20. “When a patent thus describes
the features of the ‘present invention’ as a whole, this
description limits the scope of the invention.” Verizon
Servs. Corp. v. Vonage Holdings Corp., 503 F.3d 1295,
1308 (Fed. Cir. 2007); see also TiVo, Inc. v. EchoStar
Commc’ns Corp., 516 F.3d 1290, 1300 (Fed. Cir. 2008).
     The specification discloses various methods of affixing
the two disks to one another, including gluing, bonding,
fusing, and sewing. It warns that “[t]he adhesion between
the two central membrane portions should be strong
enough to ensure that the two disks will not become
separated from one another,” ’291 patent col. 7 ll. 50–53,
indicating that the membrane disks forming the conjoint
disk are structurally distinct (and thus prone to “sepa-
rate,” rather than “tear”). All conjoint disks described or
pictured in the specification are structurally consistent
with two discrete surfaces adhered together in various
ways. See, e.g., ’291 patent fig.12; col. 9 ll. 15–20; col. 7 ll.
62–66; col. 8 ll. 60–63. Moreover, the specification dis-
closes that “the conjoint disk may include another piece of
material” that is “desirably disposed between the two
membranes and sewn or otherwise bonded to the two
membranes in defining the conjoint disk”—a configura-
tion that can only make sense if the disk membranes are
separate, physically distinct structures. ’291 patent col. 7
ll. 62–67. In other words, a device formed by attaching
two disks together “is not just the preferred embodiment
of the invention; it is the only one described.” Gen. Am.
Transp. Corp. v. Cryo-Trans, Inc., 93 F.3d 766, 770 (Fed.
Cir. 1996).
    The district court’s construction is further buttressed
by the prosecution history. During the prosecution of the
10                    REGENTS UNIV OF MINN   v. AGA MEDICAL
’951 application, the predecessor to the ’291 patent, 4 the
PTO examiner rejected the relevant claims as anticipated
by King’s prior art septal occluder, which also possessed
two flexible occluding disks. The King device comprised
two membranes supported by umbrella-like radial frames,
which were individually delivered through a catheter.
Once inside the heart, they were connected at a central
“hub,” and the umbrellas were opened to block the septal
defect. J.A. 1671. The University, in its response to the
PTO’s office action, argued that King’s umbrella-like
structures had to be “attached to one another after they
are deployed in a patient’s beating heart” using a “com-
plex multi-component hub,” while the “two disks” of the
University’s device, “each formed of a membrane and a
frame,” were advantageously assembled prior to insertion
in the catheter, and the assembly was simplified by
“attach[ing] the membranes of the two disks essentially
directly to one another” to form a “conjoint disk.” J.A.
1706–08.
     Although the ’951 application was abandoned, a divi-
sion of that application produced the predecessor ’217
patent. Like the ’951 application, the ’217 patent requires
“a central portion of the membrane of the first disk being
affixed to a central portion of the membrane of the second
disk to define a central conjoint disk,” ’217 patent col. 18
ll. 37–39; J.A. 5227, which is claim language substantially
identical to that of the ’291 patent. The Examiner’s
Supplemental Notice of Allowability indicated that “[t]he

     4 The ’291 patent issued from Application No.
08/756,776 (filed Nov. 26, 1996), which is a division of
Application No. 08/284,766 (filed Aug. 2, 1994) (issued as
U.S. Pat. No. 5,578,045), which is a division of Application
No. 08/062,095 (filed May 14, 1993) (issued as U.S. Pat.
No. 5,334,217), which is a division of Application No.
07/822,951 (filed Jan. 21, 1992) (“the ’951 application”).
The ’951 application was abandoned.
 REGENTS UNIV OF MINN    v. AGA MEDICAL                         11
primary reason for the allowance of the [’217 patent’s]
claims [wa]s the inclusion, in all the claims, of the limita-
tion that . . . a first membrane is connected to a central
portion of a second membrane to form a conjoint disk.”
J.A. 5274 (emphasis added). 5 Thus, the prosecution
history supports the district court’s construction of the
claims.
    Finally, the district court’s construction is faithful to
the ordinary meaning of the language of claim 1. Accord-
ing to dictionaries predating the 1996 filing of the ’291
patent, the word “affix” means:
    1. to fasten, join or attach (usually fol. by to): to af-
    fix stamps to a letter. 2: to put or add on; append:
    to affix a signature to a contract. 3: to impress (a
    seal or stamp). 4. to attach (blame, reproach, ridi-
    cule, etc.).



    5     During prosecution of the European counterpart
to the patents-in-suit, the University distinguished a
prior art Russian device by asserting that a device “made
in one piece with a tubular part . . . does not comprise two
disks with a central portion of a first disk being affixed to
a central portion of the second disk.” Regents, 660 F.
Supp. 2d at 1045. The University contends that its posi-
tion on appeal is not inconsistent with those representa-
tions, because “[i]t was the absence of occluding disks
joined (i.e., affixed) in the area of their respective central
portions—not the unitary or non-unitary construc-
tion . . . that was being discussed.” Appellant’s Br. 29.
While we do not find it necessary to rely on the European
proceedings, the position taken by the University in those
proceedings only supports the conclusion that, as a matter
of common sense, a device defined as two disks affixed
together to form a conjoint disk cannot also be a one-piece,
tubular structure.
12                      REGENTS UNIV OF MINN   v. AGA MEDICAL
Random House Unabridged Dictionary 34 (2d ed. 1993),
or:
     1: to attach physically (as by nails or glue):
     FASTEN . . . 2: to attach in any way: connect
     with: ADD, SUBJOIN . . . 3: IMPRESS . . . .
Webster’s Third New International Dictionary 36 (1993).
The ordinary meaning of “conjoint” is “joined together;
united; combined; associated,” or “pertaining to or formed
by two or more in combination; joint,” Random House
Unabridged Dictionary 430 (emphasis added), and accord-
ing to the note on synonyms of “join” in Webster’s Third,
“CONJOIN usu[ally] emphasizes both the togetherness of
a joining and the separateness of the things joined.”
Webster’s Third New International Dictionary 1219 (em-
phasis added). As further explained by Webster’s Third,
     [a]lthough they are used to signify a more specific
     union, LINK, CONNECT, JOIN, and CONJOIN
     in their nonphysical application may suggest a
     bringing or coming together as general and un-
     specified as that implied by RELATE or
     ASSOCIATE but tend more, esp[ecially] in physi-
     cal application, to signify a junction of some kind,
     often an inseparable junction as by a chain or by
     bonding. CONNECT is the most general of these
     four and suggests a loose attachment, esp[ecially]
     one that preserves the identity of the elements and
     the evidence of the connection . . . LINK suggests a
     slightly closer coupling[,] esp[ecially] in the physi-
     cal application of the word in which is implied in-
     separability but of still clearly identifiably
     separate elements . . . JOIN usu[ally] suggests
     strongly the idea of physical or moral contact or
     junction or the making of a continuity of two or
     more things . . . .
Id. (emphases added). The dictionary definitions support
the conclusion that when a physical object is described as
 REGENTS UNIV OF MINN    v. AGA MEDICAL                      13
having been “affixed,” “joined,” “connected,” or “con-
join[ed]” to another object, it means that those objects
were previously separate.
     The University argues that the district court improp-
erly imported process limitations into the construed
claims. We disagree. Words like “affixed” or “conjoint,”
which when “read in context, describe[] the product more
by its structure than by the process used to obtain it,” are
product limitations, not process limitations, see, e.g.,
Hazani v. U.S. Int’l Trade Comm’n, 126 F.3d 1473, 1479
(Fed. Cir. 1997) (citing In re Moore, 439 F.2d 1232, 1236
(CCPA 1971)), and are “commonly and by default inter-
preted in their structural sense,” 3M Innovative Props.
Co. v. Avery Dennison Corp., 350 F.3d 1365, 1371 (Fed.
Cir. 2003); see also In re Garnero, 412 F.2d 276, 278–79
(CCPA 1969) (“‘[I]ntermixed,’ ‘ground in place,’ ‘press
fitted,’ ‘etched,’ and ‘welded,’ all . . . at one time or another
have been separately held capable of construction as
structural, rather than process, limitations.”). When a
patentee chooses to use these words, they should be given
their ordinary meanings with respect to the claimed
product’s structure. See, e.g., Vanguard Prods. Corp. v.
Parker Hannefin Corp., 234 F.3d 1370, 1372–73 (Fed. Cir.
2000); Hazani, 126 F.3d at 1479. In Miken Composites,
L.L.C. v. Wilson Sporting Goods Co., 515 F.3d 1331, 1337
(Fed. Cir. 2008), we rejected the patentee’s contention
that the district court impermissibly imported a process
limitation into a product claim, concluding that the ordi-
nary meaning of the word “insert” required a particular
relationship between the “insert” and a surrounding
frame:
    To contend . . . that it does not matter whether an
    insert is placed into a pre-existing frame or
    whether a frame is built around it ignores that
    ordinary and customary meaning. . . . As for [the
    patentee’s] contention that the district court im-
    permissibly imported a process limitation into a
14                    REGENTS UNIV OF MINN   v. AGA MEDICAL
     product claim, we disagree. As we have discussed,
     the district court merely adopted an ordinary
     meaning of the term ‘insert.’
Id. Similarly, in Vanguard, we “agree[d] with the district
court that the word ‘integral’ describes the relationship
between the elastomeric layers, not the means of joining
them,” and held that “‘integral’ is used here in its ordi-
nary sense to mean formed as a unit with another part,”
because “the term was used to describe the product, and
not as a designation of a specific manufacturing process.”
234 F.3d at 1371–72. Our reading of the ’291 patent is
fully consistent with the approach used in our previous
cases.
    In sum, the ’291 patent’s claims “consistently use the
term[s]” affixed and conjoint “in the sense of [their] ordi-
nary meaning[s],” Miken, 515 F.3d at 1337, indicating
that the disks are discrete structures. The specification,
“the single best guide to the meaning of a disputed term,”
Vitronics, 90 F.3d at 1582, “comports with the plain
language of the claims, fully supporting the conclusion”
that the disks are separate, see Becton, Dickinson & Co. v.
Tyco Healthcare Grp., 616 F.3d 1249, 1255 (Fed. Cir.
2010). Finally, the prosecution history shows that the
University described the innovative aspect of the claimed
device as an improved way of connecting the two disks.
We conclude that the district court properly construed the
’291 patent as requiring two physically separate disks.
                     B. Infringement
    On appeal, the University argues that AGA’s mesh
tube devices infringe even under the district court’s claim
construction, because AGA’s sales literature describes
them as having two “disks.” However, AGA’s sales de-
scriptions neither expand the ’291 patent nor bring AGA’s
device within its scope. It is undisputed that AGA’s
accused occluders are not constructed from two physically
separate disks. Regents, 2011 WL 13943, at *9. AGA’s
 REGENTS UNIV OF MINN   v. AGA MEDICAL                    15
devices are made from lengths of mesh tubing; the tubing
is molded into two flattened end portions separated by a
narrow waist. The wires of the mesh run continuously
from one end of the device to the other. At no point are
two halves of the tube “affixed” to one another, and no
structure resembling a “conjoint disk” is present between
them. The district court thus correctly determined that
no reasonable jury could find that AGA’s devices infringe
the ’291 patent. Id. We therefore affirm the district
court’s grant of summary judgment of non-infringement to
AGA with respect to the ’291 patent.
                   II. The ’281 Patent
    Like the ’291 patent, the ’281 patent is directed to a
transcatheter septal occluder device. Claim 1 of the ’281
patent describes the device as comprising two “members,”
each having a “self-expanding structure”:
   1. A septal defect closure device comprising a first
   member and a second member each comprising a
   self-expanding structure exhibiting a spring-like
   behavioural component for moving the member be-
   tween a compressed orientation for passage
   through a medical instrument having an inner di-
   ameter and an expanded orientation having an
   enlarged diameter for tautly holding at least a
   portion of the closure device against a septum, the
   enlarged diameter of the member being greater
   than the inner diameter of the medical instru-
   ment; each of the first and second members also
   including a central portion, at least a substantial
   portion of the central portion of the second member
   being in communication with at least a substantial
   portion of the central portion of the first member.
’281 patent col. 18 ll. 11–24 (emphases added). The
specifications of the two patents are generally the same,
including the description of the preferred embodiment
16                     REGENTS UNIV OF MINN   v. AGA MEDICAL
with a jointed wire frame, which was discussed above.
See ’281 patent figs. 3, 4.
    The district court held that the ’281 claims’ reference
to “members” did not require separateness, and thus a
reasonable jury could conclude the claims were infringed
by AGA’s devices. Regents, 2011 WL 13943, at *9. How-
ever, the court held that the asserted claims of the ’281
patent were anticipated. Regents, 835 F. Supp. 2d at 723–
26. Like an infringement analysis, an anticipation analy-
sis has two parts: first, the disputed claim terms are
construed, then the construed claims are compared to the
prior art. In re Aoyama, 656 F.3d 1293, 1296 (Fed. Cir.
2011). A patented invention is anticipated by a prior art
reference if that reference discloses all elements of the
claimed invention, including means-plus-function struc-
tures or their equivalents. See, e.g., Kegel Co. v. AMF
Bowling, 127 F.3d 1420, 1430 (Fed. Cir. 1997). “While
anticipation is a question of fact, ‘it may be decided on
summary judgment if the record reveals no genuine
dispute of material fact,’” a decision that we review de
novo. Leggett & Platt, Inc. v. VUTEk, Inc., 537 F.3d 1349,
1352 (Fed. Cir. 2008) (quoting Golden Bridge Tech., Inc. v.
Nokia, Inc., 527 F.3d 1318, 1321 (Fed. Cir. 2008)).
Whether the prosecution history imposes a limitation on
the range of equivalents is a legal determination reviewed
de novo. J&M Corp. v. Harley-Davidson, Inc., 269 F.3d
1360, 1366 (Fed. Cir. 2001).
     In this case, the question is whether the prior art de-
vice described in the Lock article anticipated claims 1, 4,
and 5 of the ’281 patent. Independent claim 1, set forth in
full above, states in relevant part:
     1. A septal defect closure device comprising a first
     member and a second member each comprising a
     self-expanding structure exhibiting a spring-like
     behavioural component for moving the member be-
     tween a compressed orientation . . . and an ex-
 REGENTS UNIV OF MINN   v. AGA MEDICAL                       17
    panded orientation . . . , at least a substantial por-
    tion of the central portion of the second member be-
    ing in communication with at least a substantial
    portion of the central portion of the first member.
’281 patent col. 18 ll. 11–24 (emphasis added). Dependent
claim 4 states:
    4. The device of claim 1, wherein the first member
    in its compressed orientation extends primarily
    distally from the second member and the second
    member in its compressed orientation extends
    primarily proximally from the first member, each
    member in its expanded orientation extending
    primarily radially outward from its central por-
    tion.
Id. at col. 18 ll. 31–36. Dependent claim 5 states:
    5. The device of claim 1, wherein each of the first
    and second members comprises a flexible fabric
    disk.
Id. at col. 18 ll. 37–38. The district court determined that
although the prior art King device anticipated claims 1
and 5, King did not satisfy claim 4, because of the orienta-
tion of its umbrella-like radial frames. Regents, 835 F.
Supp. 2d at 717–22. However, the district court deter-
mined that all three claims were anticipated by the Lock
device, which, like King, used umbrella-like radial frames.
Id. at 723–26. The University agrees that the Lock device
has all the limitations of the three asserted claims, with
the exception of the following two elements: (1) a struc-
ture satisfying the means-plus-function limitation, and (2)
structures “in communication with” each other, and
having “at least substantial portions of the[ir] central
portion[s]” in communication with one another.
18                     REGENTS UNIV OF MINN   v. AGA MEDICAL
           A. The means-plus-function limitation
     Although claim 1 of the ’281 patent was not drafted in
standard means-plus-function language, the court deter-
mined, and the parties now agree, that the portion read-
ing:
     a self-expanding structure exhibiting a spring-like
     behavioural component for moving the member
     between a compressed orientation . . . and an ex-
     panded orientation
is a means-plus-function element, ’281 patent col. 18 ll.
11–16, with the function of “moving the member from a
compressed orientation to an expanded orientation,”
Regents, 660 F. Supp. 2d at 1051. Under section 112 ¶ 6,
now recodified as 35 U.S.C. section 112(f), a means-plus-
function claim limitation includes both the corresponding
structures disclosed by the specification as means of
performing the function, and the equivalents of those
structures. See Mettler-Toledo, Inc. v. B-Tek Scales, LLC,
671 F.3d 1291, 1296 (Fed. Cir. 2012). Here, the district
court concluded that the specification disclosed two corre-
sponding structures: “a frameless membrane made of a
thin piece of a superelastic material,” and “a flexible,
elastically deformable frame carried around the periphery
of the member” (the “peripheral frame structure”). Re-
gents, 660 F. Supp. 2d at 1050–52. The parties do not
dispute the identification of these structures.
    Neither party argues that the Lock device has a
frameless superelastic membrane or a peripheral frame.
However, the district court concluded that Lock’s radial,
umbrella-like frame was an equivalent of the peripheral
frame structure in the claimed device. For purposes of
section 112(f), an equivalent of the disclosed structure
performs the same function as the disclosed structure, in
substantially the same way, with substantially the same
result. See, e.g., JVW Enters. v. Interact Accessories, Inc.,
424 F.3d 1324, 1333 (Fed. Cir. 2005). AGA presented
 REGENTS UNIV OF MINN   v. AGA MEDICAL                   19
expert evidence, accepted by the district court, that Lock’s
“springy” radial frame performed the same function as the
peripheral frame structure—“mov[ing] [the device] from a
compressed to an expanded orientation”—in substantially
the same way, with substantially the same result. Re-
gents, 835 F. Supp. 2d at 720.
     The University argues that the district court was
wrong to treat this issue as undisputed, because there
was conflicting expert testimony as to equivalence. The
district court disagreed, determining that there was no
conflicting expert testimony, because “on the question of
equivalence, [the University’s expert] O’Laughlin . . .
fail[ed] to offer any evidence or analysis.” Id. at 725. The
district court correctly found O’Laughlin’s testimony on
equivalence to be “a conclusion supported by no explana-
tion or reasoning,” and therefore inadequate. Id. at 720.
“Conclusory expert assertions cannot raise triable issues
of material fact on summary judgment.”             Sitrick v.
Dreamworks, LLC, 516 F.3d 993, 1001 (Fed. Cir. 2008)
(citing Dynacore Holdings Corp. v. U.S. Philips Corp., 363
F.3d 1263, 1278 (Fed. Cir. 2004)).
    This leads us to the University’s primary argument:
that during prosecution it disclaimed the use of a radial
frame as an equivalent of the peripheral frame. The
University argues that this disclaimer took place during
prosecution of the ’951 application, which was the prede-
cessor to the patents-in-suit. Independent claim 1 of the
’951 application stated:
    1. A septal defect closure device comprising first
    and second occluding disks, each disk comprising
    a flexible, biologically compatible membrane hav-
    ing a periphery, and an elastically deformable
    frame carried about the periphery of the mem-
    brane. . . .
J.A. 1625 (emphasis added). The claim did not include a
means-plus-function element. The PTO examiner rejected
20                     REGENTS UNIV OF MINN   v. AGA MEDICAL
the claim as anticipated by King, explaining that King
disclosed features including “occluding disks” and “frames
carried about the periphery of the disks by sutures.” J.A.
1671.
    The University criticized and distinguished King, ar-
guing, inter alia, that unlike King, the claimed device did
not have an umbrella-like radial frame, but rather a
frame “extend[ing] along the periphery of the membrane”
of each disk. J.A. 1706–08. The University also submit-
ted an amendment which it described as expressly limit-
ing the claim language to “a frame which extends along
the periphery of the disk, something which King’s radial
arms simply do not do.” J.A. 1707. The amendment
replaced “carried about” with “extending along and at-
tached adjacent to.” J.A. 1698, 1707. After the amend-
ment, the ’951 claim language read:
     1. A septal defect closure device comprising first
     and second occluding disks, each disk comprising
     a flexible, biologically compatible membrane hav-
     ing a periphery and an elastically deformable
     frame extending along and attached adjacent to
     the periphery of the membrane . . .
See J.A. 1625 (original language); J.A. 1698, 1707 (ex-
plaining the relevant substitution in language) (emphasis
added). (The University and examiner apparently never
discussed the Lock device in connection with any of the
patents in the family, although Lock was mentioned in
the specification, and at least one article describing the
Lock device was before the examiner). Claim 1 was
subsequently allowed. 6



     6  The prosecution history establishes unequivocally
that the University understood the amendment to claim 1
to have effectively traversed the rejection over King. In
response to the next Office Action, which rejected claims
 REGENTS UNIV OF MINN   v. AGA MEDICAL                    21
    When an applicant tells the PTO that a prior art ref-
erence lies outside the scope of his claim, he is bound by
that argument. Southwall Techs., Inc. v. Cardinal IG Co.,
54 F.3d 1570, 1579–80 (Fed. Cir. 1995). In this case, no
one disputes that the University effected a clear and
unambiguous disclaimer of King’s radial frame with
respect to the language describing the “elastically de-
formable frame” in amended claim 1 of the ’951 applica-
tion.    Nor is there any apparent dispute that the
University’s disclaimer of King’s radial frame is also
applicable to the similar radial frame disclosed by Lock.
The question is whether the University’s disclaimer
carries forward to the means-plus-function language used
in claim 1 of the ’281 patent.


18 and 27 as anticipated by King, the University amended
those claims in the same way as it had amended claim 1:
   As noted above, applicant has . . . amended claims
   18 and 27 to replace the phrase “carried about the
   periphery” with “extending along and attached ad-
   jacent to the periphery”. Aside from a myriad of
   other distinctions in the use and structure of these
   devices, applicant respectfully submits that the
   radially extending arms employed by King do not
   extend about the periphery of the “membrane”
   taught therein. Accordingly, applicant respectful-
   ly submits that these claims are readily distin-
   guishable from King’s teachings and therefore are
   not anticipated by this reference.
Applicant’s Oct. 20, 1992 Response to July 20, 1992 Office
Action at 25, Regents of the Univ. of Minn. v. AGA Med.
Corp., No. 07-CV-4732 (D. Minn. Mar. 6, 2009), ECF No.
70-25. The ’951 application was eventually abandoned,
but amended claim 1 eventually issued from a division of
that application as claim 1 of the ’217 patent. See ’217
patent col. 18 ll. 29–34.
22                     REGENTS UNIV OF MINN   v. AGA MEDICAL
    Our law makes clear that “[j]ust as prosecution histo-
ry estoppel may act to estop an equivalence argument
under the doctrine of equivalents, positions taken before
the PTO may bar an inconsistent position on claim con-
struction under § 112, ¶ 6.” Alpex Computer Corp. v.
Nintendo Co., 102 F.3d 1214, 1221 (Fed. Cir. 1996). Thus,
prosecution history disclaimer may limit the range of
equivalent structures that fall within the scope of a
means-plus-function limitation. See, e.g., J&M, 269 F.3d
at 1367. We have also held that a disclaimer made during
the prosecution of a patent application may operate as a
disclaimer with respect to later patents of the same
family. Verizon, 503 F.3d at 1306.
    The problem for the University is that this limitation
of the ’951 application was not carried forward to the ’281
patent. After the ’951 application was abandoned in 1993,
successive divisions produced the ’281 patent, which
issued in 2000. 7 Over the course of four divisional appli-
cations (and seven years of prosecution) the amended
claim limitations disappeared from the ’281 patent, to be
replaced with the means-plus-function limitation:
     1. A septal defect closure device comprising a first
     member and a second member each comprising a
     self-expanding structure exhibiting a spring-like
     behavioural component for moving the member be-


     7  The ’281 patent issued from Application No.
09/271,762 (filed Apr. 22, 1999), which is a division of
Application No. 08/756,776 (filed Nov. 26, 1996), which is
a division of Application No. 08/284,766 (filed Aug. 2,
1994) (issued as U.S. Pat. No. 5,578,045), which is a
division of Application No. 08/062,095 (filed May 14, 1993)
(issued as U.S. Pat. No. 5,334,217), which is a division of
the ’951 application (filed Jan. 21, 1992).
 REGENTS UNIV OF MINN   v. AGA MEDICAL                  23
   tween a compressed orientation . . . and an ex-
   panded orientation . . . .
 ’281 patent col. 18 ll. 11–24 (emphasis added). There is
no mention of a frame, peripheral or otherwise, in any
claim of the ’281 patent.
    We have explained that “[w]hen the purported dis-
claimers [made during prosecution] are directed to specif-
ic claim terms that have been omitted or materially
altered in subsequent applications (rather than to the
invention itself), those disclaimers do not apply.” Saun-
ders Grp., Inc. v. Comfortrac, Inc., 492 F.3d 1326, 1333
(Fed. Cir. 2007). In general, a prosecution disclaimer will
only apply to a subsequent patent if that patent contains
the same claim limitation as its predecessor. See, e.g.,
Ventana Med. Sys. v. Biogenix Labs., Inc., 473 F.3d 1173,
1182 (Fed. Cir. 2006) (“[P]rosecution disclaimer generally
does not apply when the claim term in the descendent
patent uses different language.”); Invitrogen Corp. v.
Clontech Labs, Inc., 429 F.3d 1052, 1078 (Fed. Cir. 2005)
(“[T]he prosecution of one claim term in a parent applica-
tion will generally not limit different claim language in a
continuation application.”); ResQNet.com, Inc. v. Lansa,
Inc., 346 F.3d 1374, 1383 (Fed. Cir. 2003) (“Prosecution
history is irrelevant to the meaning of [a] limitation [if]
the two patents do not share the same claim language.”);
Biogen, Inc. v. Berlex Labs., Inc., 318 F.3d 1132, 1141
(Fed. Cir. 2003) (“When the applicant is seeking different
claims in a divisional application, estoppel generally does
not arise from the prosecution of the parent.”). 8


   8    The sole exception is when the disclaimer is di-
rected to the scope of the invention as a whole, not a
particular claim. See, e.g., Ormco Corp. v. Align Tech.,
Inc., 498 F.3d 1307, 1314–15 (Fed. Cir. 2007) (the patent-
ee’s statements “w[ere] not associated with particular
language from [the] claims” but were instead directed to
24                     REGENTS UNIV OF MINN   v. AGA MEDICAL
    Thus, our cases establish that the two patents must
have the same or closely related claim limitation lan-
guage. If the language of the later limitation is signifi-
cantly different, the disclaimer will not apply. For
example, this court recently concluded in Digital-Vending
that an inventor’s arguments with respect to certain claim
limitations in a parent should not apply to significantly
different claim limitations in a divisional application.
Digital-Vending Servs. Int’l, LLC v. Univ. of Phoenix, Inc.,
672 F.3d 1270, 1277 (Fed. Cir. 2012). The court explained
that “in light of the language of the later issued claims,”
and the fact that “the inventors never argued” that the
disclaimer applied “when pursuing the divisional applica-
tion that gave rise to the [patent-in-suit],” application of
the disclaimer to the divisional’s claims would be improp-
er. Id.
    Although the ’281 patent’s claims do not include a pe-
ripheral frame limitation, the University argues that the
peripheral frame structure described in the specification
satisfies the same language requirement. As amended,
claim 1 of the ’951 application required “an elastically
deformable frame extending along and attached adjacent
to the periphery of the membrane.” See J.A. 1698 (em-


the “present invention” and the “overall method” claimed).
In circumstances closely analogous to this case, this court
has held that “the alleged disclaimer distinguishing the
prior art focused on a particular claim limitation . . . and
was not directed to the invention as a whole.” Saunders
Grp., 492 F.3d at 1333. In this case, the University’s
statements and amendments were directed to specific
claims pertaining to the framed embodiments, not to the
overall invention. The University does not contend that
its representations restricted the scope of its invention “as
a whole.”
 REGENTS UNIV OF MINN   v. AGA MEDICAL                  25
phasis added). The structure corresponding to the means-
plus-function limitation in claim 1 of the ’281 patent has
“[a] frame . . . [that] is attached to and desirably extends
substantially around the periphery of the membrane.”
’281 patent col. 5 ll. 7–8 (emphasis added).
    The University is mistaken. The proper inquiry is
whether the scope of the claim limitation is substantially
the same in the subsequent application as it was in the
earlier application. See, e.g., Advanced Cardiovascular
Sys., Inc. v. Medtronic, Inc., 265 F.3d 1294, 1305 (Fed Cir.
2001) (prosecution history may be relevant if “it addresses
a limitation in common with the patent in suit”); Elkay
Mfg. Co. v. Ebco Mfg. Co., 192 F.3d 973, 980 (Fed. Cir.
1999) (“[T]he prosecution history regarding a claim limi-
tation . . . applies with equal force to subsequently issued
patents that contain the same limitation.”). In disclaim-
ing claim coverage in light of certain prior art, the appli-
cant does not thereby act as a lexicographer, redefining
individual words. The appropriate focus is on the scope of
the claim element, not the meaning of particular words in
isolation. This is why our cases evaluate the similarity
between the earlier and later claim limitations, carrying
disclaimer forward if there are only immaterial differ-
ences, see, e.g., Elkay, 192 F.3d at 979–80 (carrying dis-
claimer forward where “[t]he relevant portion of claim 1 of
the [later] patent is identical to the above-quoted limita-
tion in claim 1 of the [first] patent,” except for a single
word); see also Invitrogen, 429 F.3d at 1078 (amendment
“to a related limitation in the parent application” is
relevant to “a later (though differently worded) limita-
tion”), and declining to extend disclaimer to a subsequent
limitation that contained “materially” different claim
language, see Saunders Grp., 492 F.3d at 1333; see also
Medtronic, 248 F.3d at 1315 (“[N]one of the claims of the
[earlier] patent contain the same limitation that we are
construing from the [later] patent,” and “[a]ccordingly, we
decline . . . to consider the [earlier] patent’s prosecution
26                     REGENTS UNIV OF MINN   v. AGA MEDICAL
history for the purpose of construing the limitation in
question.”).
    Our requirement that the patents share “limitations
in common” is not a mere technicality: it is necessary to
support the inference that the patentee’s earlier argu-
ments are also applicable to the claim limitations of the
patent-in-suit. See, e.g., Digital-Vending, 672 F.3d at
1277. Without claim language that makes that linkage
clear, neither the PTO examiner nor the patentee’s com-
petitors would be on notice as to the true scope of the later
patent’s claims. We have held that it is permissible for a
patentee to take a different approach to claiming an
invention in subsequent patents, either by adding limita-
tions or by altering the claims’ format. When the patent-
ee does so, however, we cannot rely on the dubious
argument that dissimilar claims present equivalent issues
of validity, or that the applicant’s disclaimer with respect
to one claim would be equally applicable to another claim.
     Here, the basis for distinguishing prior art in the sec-
ond application is not the same as in the first. The
amended ’951 claim language, “[a] septal defect closure
device comprising first and second occluding disks, each
disk comprising . . . an elastically deformable frame
extending along and attached adjacent to the periphery of
the membrane,” see J.A. 1625, 1698, 1707, was not carried
over to the later application which gave rise to the ’281
patent. The later application instead used the language
“[a] septal defect closure device comprising a first member
and a second member each comprising a self-expanding
structure,” ’281 patent col. 18 ll. 11–24, and disclosed two
corresponding structures in the specification, one of which
contained a peripheral frame structure. The scope of
claim 1 in the second application is plainly not the same
as it was in the first application, and it would be inappro-
priate to import the first application’s limitations into the
different context of the second application. “Although
statements in a file history may of course be used to
 REGENTS UNIV OF MINN   v. AGA MEDICAL                  27
explain and potentially limit the meaning of claim limita-
tions,” they “cannot be used to add an entirely new limita-
tion to the claim.” Serrano v. Telular Corp., 111 F.3d
1578, 1584 (Fed. Cir. 1997); see also Markman, 52 F.3d at
980 (“Although the prosecution history can and should be
used to understand the language used in the claims, it . . .
cannot ‘enlarge, diminish, or vary’ the limitations in the
claims.”). It is likewise inappropriate to apply a narrow-
ing disclaimer to limitations that are materially different
from the limitation to which it originally applied.
    In other words, claim 1 of the ’281 patent contains a
different claim limitation than its predecessors and
captures different subject matter. From the examiner’s
perspective, prior art devices like King and Lock are
relevant in different ways to the ’951 application’s literal
“frame carried about the periphery” requirement, and the
’281 claim’s functional “self-expanding structure” re-
quirement. During the prosecution of the first applica-
tion, the University never told the PTO examiner that a
radial frame was ineffective at expanding a device’s
occluding disks; instead, the University criticized the
King device as being too difficult to assemble and keep in
position. It does not follow that the University found the
radial frame unacceptable for use in performing the
claimed expanding function in the redrafted ’281 patent.
Thus, the original disclaimer does not carry over to limit
the range of equivalents here, and does not negate the
district court’s anticipation finding. 9

   9     The University also argues that the specification
of the ’281 patent disclaims Lock’s radial frame. But the
’281 specification only expresses concern about using
radial arms to hold the expanded device in place against
the septum of the beating heart. It does not disavow the
use of a radial frame to move the device from a com-
pressed orientation to an expanded orientation upon
deployment.
28                     REGENTS UNIV OF MINN   v. AGA MEDICAL
 B. “In communication with” and “at least a substantial
                       portion”
     The University’s remaining two challenges to the dis-
trict court’s anticipation analysis pertain to the require-
ment that “at least a substantial portion of the central
portion of the first member” be “in communication with at
least a substantial portion of the second member.” See
Regents, 835 F. Supp. 2d at 716. The district court con-
strued this claim to require that substantial portions of
the central portions of the members communicated
“movement.” See id. at 721. The University styles its
arguments as challenges to the district court’s application
of this claim construction, but they are essentially indirect
objections to the claim construction itself, which the
University did not raise to the district court.
    First, the University contends that the district court
wrongly allowed translational movement communicated
between Lock’s members to satisfy the claim limitation.
The University argues that the members are required to
communicate expansion or contraction movement, not
translational movement. But the district court correctly
stated that its claim construction placed no restriction
whatsoever on the type of movement required by the
claim. Id. (“[T]he Court’s claim construction says nothing
about ‘expansion or contraction movement’; it refers to
‘movement,’ plain and simple.”). We agree with the
district court that the University’s interpretation of the
claim limitation is inconsistent with the district court’s
construction. If the University objected to that construc-
tion, it should have presented its objection and its alter-
native construction to the district court.        But the
University’s claim construction briefs, including supple-
mental briefs directed specifically to the phrase “in com-
munication with,” never argued that the correct
construction required a particular type of movement. The
University has therefore waived any objection to this
aspect of the district court’s construction, and cannot
 REGENTS UNIV OF MINN   v. AGA MEDICAL                  29
advance a new reading of the claim language indirectly on
appeal. See, e.g., Digital-Vending, 672 F.3d at 1273.
     The University’s second argument fares no better.
The University’s argument appears to be that the “central
portion” of each member must fill the septal defect, and
that Lock’s hub does not satisfy this requirement. How-
ever, the plain language of the asserted claims does not
support this reading, and the district court’s claim con-
struction does not require it. Despite multiple opportuni-
ties to offer briefing on this limitation, the University
never objected to this aspect of the district court’s con-
struction or argued for an alternative construction includ-
ing this requirement; it is therefore barred from making
this argument on appeal. 10 We conclude that the district
court did not err in finding that the Lock device satisfied
all limitations of the asserted claims.
    Because the district court properly concluded that
Lock anticipates the asserted claims 1, 4 and 5 of the ’281
patent, we affirm the district court’s grant of summary
judgment of invalidity to AGA with respect to those
claims.
                        AFFIRMED



   10   The University also seems to suggest that in the
Lock device, the area of attachment between the two
members is too small to be a “substantial portion.” But
the district court rightly rejected this argument because
the claim construction only requires that the members
“transmit movement[]between a substantial portion of
their central portions,” and “a reasonable jury would have
to find that [Lock’s] umbrellas communicate (by way of
their central attachment point) over a substantial portion
of their central portions.” Regents, 835 F. Supp. 2d at
726.
