  United States Court of Appeals
      for the Federal Circuit
               __________________________

      01 COMMUNIQUE LABORATORY, INC.,
              Plaintiff-Appellant,

                            v.
                   LOGMEIN, INC.,
                   Defendant-Appellee.
               __________________________

                       2011-1403
               __________________________

   Appeal from the United States District Court for the
Eastern District of Virginia in Case No. 10-CV-1007, Senior
Judge Claude M. Hilton
              ___________________________

                 Decided: July 31, 2012
              ___________________________

   THOMAS H. SHUNK, Baker Hostetler LLP, of Cleveland,
Ohio, argued for plaintiff-appellant. With him on the brief
were THOMAS D. WARREN, CHRISTINA J. MOSER; and
KENNETH J. SHEEHAN, WILLIAM C. BERGMANN and A. NEAL
SETH, of Washington, DC.

   WAYNE L. STONER, Wilmer Cutler Pickering Hale and
Dorr, LLP, of Boston, Massachusetts, argued for defendant-
appellee. With him on the brief were VINITA FERRERA,
ARTHUR W. COVIELLO and ALEXANDRA W. AMRHEIN.
01 COMMUNIQUE LAB v. LOGMEIN                                       2


                 __________________________

Before RADER, Chief Judge, WALLACH, Circuit Judge, and
               FOGEL, District Judge. *
FOGEL, District Judge.

    Plaintiff-Appellant 01 Communique Laboratory, Inc.
(“01 Communique”) appeals a decision of the United States
District Court for the Eastern District of Virginia granting
summary judgment of noninfringement in favor of Defen-
dant LogMeIn, Inc. (“LogMeIn”). The district court’s deci-
sion was based on the construction of a single claim term –
“location facility” – contained in the patent-in-suit. Be-
cause we conclude that the district court’s construction of
this term was erroneous, we vacate the judgment and
remand for further proceedings.

                                 I.

    01 Communique is the owner of U.S. Patent No.
6,928,479 (“the ’479 Patent” or “the patent”), which relates
to technology that enables one computer to access another
computer remotely via the Internet. The patent contains
five independent claims describing systems, methods, and
products for enabling such remote access, as well as numer-
ous claims dependent therefrom. In broad outline, the
patent discloses use of a “locator server computer” as an
intermediary between a “remote computer” (the computer
seeking access) and a “personal computer” (the computer to
be accessed). See, e.g., ’479 Patent col. 11 ll. 1-3, col. 12 ll.
50-52, col. 13 ll. 23-25, col. 13 l. 64-col. 14 l. 1, col. 14 ll. 41-
43. The locator server computer “includes” software, re-

    *    Honorable Jeremy Fogel, District Judge, United
States District Court for the Northern District of California,
sitting by designation.
3                              01 COMMUNIQUE LAB v. LOGMEIN


ferred to in the patent as a “location facility,” that inter alia
locates the personal computer. See, e.g., id. col. 10 ll. 51-53,
col. 12 ll. 36-37, col. 13 ll. 13-14. Representative claim 1
recites:

    1. A system for providing access to a personal com-
    puter having a location on the Internet defined by a
    dynamic IP address from a remote computer, the
    system comprising:

    (a) a personal computer linked to the Internet, its
    location on the Internet being defined by either (i) a
    dynamic public IP address (publicly addressable), or
    (ii) a dynamic LAN IP address (publicly un-
    addressable), the personal computer being further
    linked to a data communication facility, the data
    communication facility being adapted to create and
    send a communication that includes a then current
    dynamic public IP address (publicly addressable) or
    dynamic LAN IP address (publicly un-addressable)
    of the personal computer;

    (b) a locator server computer linked to the Internet,
    its location on the Internet being defined by a static
    IP address, and including a location facility for lo-
    cating the personal computer; and

    (c) a remote computer linked to the Internet, the
    remote computer including a communication facil-
    ity, the communication facility being operable to
    create a request for communication with the per-
    sonal computer, and send the request for communi-
    cation to the locator server computer;

    wherein the data communication facility includes
    data corresponding to the static IP address of the lo-
01 COMMUNIQUE LAB v. LOGMEIN                                  4


    cator server computer, thereby enabling the data
    communication facility to create and send on an in-
    termittent basis one or more communications to the
    locator server computer that include the then cur-
    rent dynamic public IP address or dynamic LAN IP
    address of the personal computer; and

    wherein the locator server computer is operable to
    act as an intermediary between the personal com-
    puter and the remote computer by creating one or
    more communication sessions there between, said
    one or more communication sessions being created
    by the location facility, in response to receipt of the
    request for communication with the personal com-
    puter from the remote computer, by determining the
    then current location of the personal computer and
    creating a communication channel between the re-
    mote computer and the personal computer, the loca-
    tion facility being operable to create such
    communication channel whether the personal com-
    puter is linked to the Internet directly (with a pub-
    licly addressable) dynamic IP address or indirectly
    via an Internet gateway/proxy (with a publicly un-
    addressable dynamic LAN IP address).

’479 Patent col. 10 l. 38-col. 11 l. 15 (emphasis added to the
disputed claim term).

     01 Communique asserts infringement of the patent by
LogMeIn, a company that develops and markets remote
access products. In its order dated May 4, 2011, the district
court determined that all of the allegedly infringed claims of
the ’479 Patent require “a ‘locator server computer’ that
‘includes a location facility.’” See 01 Communique Lab., Inc.
v. LogMeIn, Inc., No. 1:10cv1007, 2011 WL 1740144, at *1
5                            01 COMMUNIQUE LAB v. LOGMEIN


(E.D. Va. May 4, 2011) (“Order”). It then construed “loca-
tion facility” as:

    a component of a locator server computer that itself:
     1) creates communication sessions between a re-
    mote computer and personal computer; 2) receives a
    request for communication with the personal com-
    puter from the remote computer; 3) locates the per-
    sonal computer (and “determines the then location
    of the personal computer”); and 4) creates a com-
    munication channel between a remote computer and
    the personal computer.

Id. at *4.

     The district court concluded that the location facility
must be contained on a single physical computer, relying
primarily upon a perceived disclaimer in the prosecution
history of a construction that would encompass distribution
of the location facility among multiple computers. Because
it determined that “[t]he LogMeIn system does not contain
any component that itself performs all the four functions
required of the location facility under the Court’s construc-
tion of the term,” the district court held as a matter of law
that LogMeIn does not infringe the ’479 Patent. Id. at *6-7.
 01 Communique appeals the district court’s construction of
the term “location facility” and the resulting grant of sum-
mary judgment of noninfringement. We have jurisdiction
under 28 U.S.C. § 1295(a)(1).

                             II.

    “[W]e review a district court’s claim construction de
novo.” Absolute Software, Inc. v. Stealth Signal, Inc., 659
F.3d 1121, 1129 (Fed. Cir. 2011). “To ascertain the scope
and meaning of the asserted claims, we look to the words of
01 COMMUNIQUE LAB v. LOGMEIN                                6


the claims themselves, the specification, the prosecution
history, and, if necessary, any relevant extrinsic evidence.”
Chicago Bd. Options Exch., Inc. v. Int’l Sec. Exch., LLC, 677
F.3d 1361, 1366 (Fed. Cir. 2012) (citing Phillips v. AWH
Corp., 415 F.3d 1303, 1315-17 (Fed. Cir. 2005) (en banc)).

    Infringement is a question of fact. Absolute Software,
659 F.3d at 1129-30. “On appeal from a grant of summary
judgment of non-infringement, we determine whether, after
resolving reasonable factual inferences in favor of the pat-
entee, the district court correctly concluded that no reason-
able jury could find infringement.” Id. at 1130.

                             III.

    Although the district court’s order refers to the location
facility as a “device,” 1 the parties agree that the location
facility is software that runs on the locator server computer.
 There is no indication in the specification that the location
facility is a physical device rather than software. The terms
“facility” and “program” are used interchangeably in the
specification, suggesting that the “facilities” referenced
throughout the patent are software, rather than hardware,
components. See ’479 Patent col. 7 ll. 42-43 (discussing a
“data communication program or facility”); id. col. 10 ll. 11-
12 (referring to “computer program facilities”). As will
become apparent, the district court’s understanding of the
location facility as a “device” may explain its ultimately
erroneous construction of the term.

    1   See Order at *6 (stating that “nothing in LogMeIn’s
accused products is a location facility as required by all of
01’s asserted claims: a device that itself receives a request
for communication with a personal computer, locates the
personal computer, and creates a communication channel
between a remote computer and a personal computer”)
(emphasis added).
7                             01 COMMUNIQUE LAB v. LOGMEIN


    The parties also agree that the location facility performs
the four functions enumerated in the district court’s claim
construction. See ’479 Patent col. 11 ll. 3-10. 01 Commu-
nique argues that because those functions are set forth
expressly in the claim, it would be “redundant and unneces-
sary” to incorporate them into the construction of “location
facility.” However, 01 Communique has not cited, and we
have not discovered, any authority for the proposition that
construction of a particular claim term may not incorporate
claim language circumscribing the meaning of the term.
The claim language makes clear that the location facility in
fact does perform the functions in question. The district
court correctly incorporated those functions into its claim
construction.

    Having addressed these preliminary matters, we now
take up the issue upon which this appeal turns – whether
the location facility must be contained entirely on a single
locator server computer as held by the district court and
asserted by LogMeIn, or whether it may be distributed
among multiple locator server computers as asserted by 01
Communique. LogMeIn argues that the district court’s
construction is supported by the fact that the claims refer to
the locator server computer in the singular. It points to
language such as the following: “a locator server computer
linked to the Internet, its location on the Internet being
defined by a static IP address.” ’479 Patent col. 10 ll. 51-53
(emphasis added); see also id. col. 10 ll. 61-62 (“the data
communication facility includes data corresponding to the
static IP address of the locator server computer”) (emphasis
added). LogMeIn asserts that “because ‘its’ and ‘the’ are
singular terms, the claimed ‘location facility’ must be a
software component that is included within a single locator
server computer.”
01 COMMUNIQUE LAB v. LOGMEIN                                  8


     LogMeIn’s argument is at odds with our well-
established precedent. “As a general rule, the words ‘a’ or
‘an’ in a patent claim carry the meaning of ‘one or more.’”
TiVo, Inc. v. EchoStar Commc’ns Corp., 516 F.3d 1290, 1303
(Fed. Cir. 2008). “The exceptions to this rule are extremely
limited: a patentee must evince a clear intent to limit ‘a’ or
‘an’ to ‘one.’” Baldwin Graphic Sys., Inc. v. Siebert, Inc., 512
F.3d 1338, 1342 (Fed. Cir. 2008) (internal quotation marks
and citation omitted). “The subsequent use of definite
articles ‘the’ or ‘said’ in a claim to refer back to the same
claim term does not change the general plural rule, but
simply reinvokes that non-singular meaning.” Id. An
exception to the general rule arises only “where the lan-
guage of the claims themselves, the specification, or the
prosecution history necessitate a departure from the rule.”
Id. at 1342-43.

    Here, nothing in the claim language or the specification
compels a departure from the general rule. The patent’s use
of words such as “a,” “its,” and “the” in the claims is insuffi-
cient to limit the meaning of “locator server computer” to a
single physical computer. LogMeIn claims that such a
limitation is supported by the specification, noting that
some figures show the location facility 6 as part of a single
locator server computer 12. See ’479 Patent Figs. 1-2.
However, the fact that a locator server computer is repre-
sented by a single box in some of the figures does not “ne-
cessitate” a departure from the general rule that “a” locator
server computer may mean “one or more” locator server
computers. More to the point, the specification also dis-
closes expressly that “Server Computer 12 may comprise
one or more computers, as is well known.” Id. col. 5 ll. 24-
25.

    LogMeIn contends that this language is not sufficiently
particular to show how the location facility would operate on
9                             01 COMMUNIQUE LAB v. LOGMEIN


more than one computer. The specification discloses that “a
number of computer program facilities are described in this
invention as separate facilities for the sake of describing the
invention. However, it should be understood that . . . such
facilities can be sub-divided into separate facilities.” ’479
Patent col. 10 ll. 11-16. Read together, the disclosures that
facilities may be subdivided and that the locator server
computer may comprise multiple computers support a
construction that the location facility may be distributed
among multiple physical computers. Even if we were to
conclude that the specification is ambiguous on this point,
such ambiguity hardly is evidence of the clear intent neces-
sary to overcome the effect of the general rule of claim
construction applicable here.

                             IV.

    “When the patentee makes clear and unmistakable
prosecution arguments limiting the meaning of a claim term
in order to overcome a rejection, the courts limit the rele-
vant claim term to exclude the disclaimed matter.” SanDisk
Corp. v. Memorex Prods., Inc., 415 F.3d 1278, 1286 (Fed.
Cir. 2005). “A patentee’s statements during reexamination
can be considered during claim construction, in keeping
with the doctrine of prosecution disclaimer.” Krippelz v.
Ford Motor Co., 667 F.3d 1261, 1266 (Fed. Cir. 2012). “An
ambiguous disclaimer, however, does not advance the
patent’s notice function or justify public reliance, and the
court will not use it to limit a claim term’s ordinary mean-
ing.” Sandisk, 415 F.3d at 1287. “There is no ‘clear and
unmistakable’ disclaimer if a prosecution argument is
subject to more than one reasonable interpretation, one of
which is consistent with a proffered meaning of the disputed
term.” Id.
01 COMMUNIQUE LAB v. LOGMEIN                               10


    In 2007, third party Citrix Systems (“Citrix”) requested
inter partes reexamination of the ’479 Patent. On reexami-
nation, the U.S. Patent and Trademark Office initially
rejected all of the patent’s claims as unpatentable over prior
art, but on July 6, 2010, it issued a Right of Appeal Notice
withdrawing the rejections as to the particular claims at
issue here. The district court concluded that “[d]uring the
re-examination of the ’479 Patent, 01 clearly and ambigu-
ously [sic] disclaimed having more than one device perform
the functions of the location facility.” Order at *4 (emphasis
in original). It appears that the district court understood
this to mean that 01 Communique disclaimed a system,
method, or product in which the location facility is distrib-
uted among multiple locator server computers. This conclu-
sion is not supported by the record.

    The district court relied upon statements made by 01
Communique’s expert, Dr. Gregory Ganger, during the
reexamination process. Dr. Ganger opined that in the
patented invention the location facility creates a communi-
cation channel between the remote computer and the per-
sonal computer, and that this “create” limitation would not
be satisfied by a location facility “that is simply used by
some other component that creates the communication
channel.” Joint Appendix (“JA”) 18002. Dr. Ganger empha-
sized that “the location facility, itself, [must] create the
communication channel.” Id. The district court apparently
read these statements to disclaim distribution of the loca-
tion facility among multiple computers. See Order at *4.
However, Dr. Ganger’s statements addressed another point
entirely – he was differentiating between technology in
which the location facility itself creates the communication
channel and technology in which some component other
than the location facility creates the communication chan-
nel. JA 18002-03. Dr. Ganger then distinguished the
patented invention – in which the location facility creates
11                           01 COMMUNIQUE LAB v. LOGMEIN


the communication channel – from prior art in which an-
other component, such as the remote computer or personal
computer, uses the location facility to create the communi-
cation channel. JA 18008-09, 18015. Dr. Ganger did not
address whether the location facility must be contained on a
single locator server computer or may be distributed among
multiple locator server computers.

    LogMeIn asserts that 01 Communique disclaimed dis-
tribution of the location facility among multiple computers
in order to avoid rejection based upon two prior art refer-
ences, referred to herein collectively as “Crichton.” 2 Dr.
Ganger described Crichton as disclosing technology in which
three separate components – a “middle proxy” sandwiched
between two “end proxies” – establish the connection be-
tween the remote computer and the personal computer. JA
18006-07. Dr. Ganger opined that the middle proxy of
Crichton corresponds to the location facility of the ’479
Patent. Id. However, he also concluded that the middle
proxy does not determine the location of the personal com-
puter, as is taught by the ’479 Patent, but instead deter-
mines the location of an end proxy, which then determines
the location of the personal computer. JA 18007. The
examiner agreed, JA 27677-78, 27692, and found the subject
claims patentable over Crichton and other prior art of
record on the basis that, “the prior art fails to teach or
suggest that the location facility determines the then cur-
rent location of the personal computer and creates a com-
munication channel between the remote computer and the
personal computer,” JA 27696. Nothing in the record sug-
gests a disclaimer based upon Dr. Ganger’s statements. As


     2The patents comprising the Crichton reference are
U.S. Patent No. 6,104,716 A and U.K. Patent No.
GB2323757. JA 27671. They are not included in the record.
01 COMMUNIQUE LAB v. LOGMEIN                               12


noted earlier, the district court’s understanding of the
location facility as a “device” may have led to its erroneous
conclusion to the contrary.

      Finally, LogMeIn contends that 01 Communique’s can-
cellation of claim 49 following its rejection by the examiner
effectively disclaimed a subdivided location facility that is
distributed among multiple computers. During reexamina-
tion, 01 Communique proposed several new claims (includ-
ing claim 49) that defined “locator server computer” to
encompass multiple computers. JA 6102-06. The record
does not include all pages of the August 19, 2009 Action
Closing Prosecution in which those claims were rejected.
However, it appears that all of the claims that disclosed
multiple locator server computers depended from claims
47 3 , 52, 58, 63, and 69, which recited a limitation that the
locator server computer verifies the personal computer’s
Internet connection. JA 28151. Because the specification
disclosed that the personal computer verifies its own Inter-
net connection, the examiner concluded that claims 47, 52,
58, 63, and 69, and claims dependent therefrom, failed to
comply with the written description requirement of 35
U.S.C. § 112. Id.

    The examiner found that there was an additional basis
to conclude that claims 49, 54, 60, 65, 71, and 75 – compris-
ing some, but not all, of the claims disclosing multiple
locator server computers – failed to comply with the written
description requirement. JA 28151. Those claims recited a
limitation that the second locator server computer facili-
tates one or more communication sessions between the


    3   The examiner indicated that claims 49-51 depended
from claim 48. JA 28151. Claim 48 depended from claim
47. JA 6104.
13                             01 COMMUNIQUE LAB v. LOGMEIN


remote computer and the personal computer but does not
locate the personal computer. Id. The examiner found that
the specification failed to suggest that the second locator
server computer does not perform the locate function. Id.
However, the examiner stated expressly that other claims
disclosing multiple locator server computers – in particular,
claims 48, 53, 59, 64, 70, and 74 – “are fully supported by
the specification of the ’479 Patent.” JA 28161. Specifically,
the examiner concluded that, “the disclosure of the ’479
Patent has never defined that the locator server computer or
server computer comprises a singular component,” and that
to the contrary, “the specification of the ’479 Patent clearly
defines that the server computer comprises one or more
computers at col. 5, lines 24-25.” JA 28159. This record
does not support LogMeIn’s position as to the effect of 01
Communique’s cancellation of claim 49.

     Accordingly, we construe the term “location facility” as4 :

     Software on a locator server computer that: (1) re-
     ceives a request for communication with the per-
     sonal computer from the remote computer; (2)
     determines the then current location of the personal
     computer; (3) creates a communication channel be-
     tween the remote computer and the personal com-

     4   This construction includes the same four functions
enumerated by the district court, although the functions
have been rephrased to track the claim language more
closely, and have been listed in a different order. However,
the construction omits the word “itself,” which the district
court imported from Dr. Ganger’s discussion of the location
facility’s “create” function. We believe that the word is
unnecessary to construction of the term “location facility,”
and that use of a singular pronoun might suggest mislead-
ingly that all of the functions of the location facility must be
performed on a single computer, despite our explicit con-
struction to the contrary.
01 COMMUNIQUE LAB v. LOGMEIN                              14


    puter; and (4) creates one or more communication
    sessions between the remote computer and the per-
    sonal computer. The locator server computer may
    comprise one or more computers, and the location
    facility may be distributed among one or more loca-
    tor server computers.

                             V.

    The district court found that LogMeIn’s accused prod-
ucts use multiple server computers, and that no single one
of those computers performs all of the functions of the
location facility. Order at *6-7. It therefore concluded that
LogMeIn’s products could not infringe the ’479 patent under
its claim construction, which required that the location
facility be contained on a single computer. Because the
district court’s ruling was based upon an erroneous claim
construction, we vacate the summary judgment of nonin-
fringement.

             VACATED and REMANDED.

    Each party shall bear its own costs.
