  United States Court of Appeals
      for the Federal Circuit
                ______________________

                 CONVOLVE, INC.,
                 Plaintiff-Appellant

      THE MASSACHUSETTS INSTITUTE OF
               TECHNOLOGY,
                  Plaintiff

                          v.

           COMPAQ COMPUTER CORP.,
               Defendant-Appellee

          SEAGATE TECHNOLOGY, INC.,
                   Defendant

          SEAGATE TECHNOLOGY, LLC,
                Defendant-Appellee
              ______________________

                      2014-1732
                ______________________

   Appeal from the United States District Court for the
Southern District of New York in No. 1:00-CV-05141,
Judge George B. Daniels.
                ______________________

              Decided: February 10, 2016
               ______________________

   JOHN THOMAS MOEHRINGER, Cadwalader, Wicker-
sham & Taft LLP, New York, NY, argued for plaintiff-
2                 CONVOLVE, INC.   v. COMPAQ COMPUTER CORP.



appellant. Also represented by GREGORY A. MARKEL,
KEVIN J. MCNAMEE, ROBERT MACAULAY POLLARO.

    CHRISTOPHER LANDGRAFF, Bartlit Beck Herman
Palenchar & Scott LLP, Chicago, IL, argued for defend-
ant-appellee Compaq Computer Corp. Also represented by
MARK FERGUSON, CHRISTOPHER R. HAGALE.

    CARTER GLASGOW PHILLIPS, Sidley Austin LLP, Wash-
ington, DC, argued for defendant-appellee Seagate Tech-
nology, LLC. Also represented by ERIKA MALEY; ROBERT
N. HOCHMAN, Chicago, IL; ERIC W. HAGEN, McDermott,
Will & Emery LLP, Los Angeles, CA.
                ______________________

     Before DYK, TARANTO, and HUGHES, Circuit Judges.
HUGHES, Circuit Judge.
    This case returns to us after a remand to the South-
ern District of New York. In the first appeal, we reversed
the district court’s summary judgment ruling that no
accused products met the patent’s “selected unwanted
frequencies” limitation and remanded for further proceed-
ings. On remand, the district court granted summary
judgment on alternative grounds. Because we agree with
the district court that Seagate’s disk drives do not possess
a user interface, but conclude that the district court erred
by importing limitations into the “command” steps and in
granting summary judgment based on intervening rights,
we again affirm-in-part, vacate-in-part, reverse-in-part,
and remand for further proceedings.
                             I
    As we explained in the first appeal, the technology at
issue relates to improvements in computer hard drives
described in U.S. Patent No. 6,314,473. Convolve, Inc. v.
Compaq Comput. Corp., 527 F. App’x 910, 913 (Fed. Cir.
2013) (Convolve I). Hard drives store data as magnetized
CONVOLVE, INC.   v. COMPAQ COMPUTER CORP.                  3



spots on the surface of disks or “platters” inside the drive.
These spots are arranged in concentric circles, called
tracks, on the surface of the platters. The hard drive also
contains an arm that “seeks” between different “tracks” to
read or write information on those tracks. As relevant to
this appeal, hard drives ordinarily employ two motors to
read and write data: (1) a spindle motor that spins circu-
lar platters, “allowing the head to cover the platters’ area
while traversing over a line or arc;” and (2) “the voice coil
motor . . . that moves the arm across the spinning plat-
ters.” Id. The process of moving the arm across the
platters, called “seeking,” generates vibrations in the arm
and the attached read/write head, which generates acous-
tic noise audible to the user. The specification describes
the inverse relationship between the seek time and the
acoustic noise: the shorter the seek time, the greater the
vibration and the greater the acoustic noise. Although
acoustic noise can be generated from both the spindle
motor and the seek process, the ’473 patent focuses on
methods and apparatuses for improving hard drives by
reducing acoustic noise generated by the movement of the
disk drive’s arm and read/write head, i.e., the seek pro-
cess. The patent describes a technique to minimize the
vibrations of the head as it moves over the rotating hard
disk that requires a “user interface” to control the speed
at which the seek arm operates such that a user could
select a quiet mode, which may have a slower read/write
time but generates less noise.
    Claim 10 is representative, and is reproduced below.
The words added during reexamination are italicized and
the words deleted are in brackets:
    Method for controlling operation of a data storage
    device, comprising:
        providing a user interface for controlling
        one of a seek time of the data storage de-
4                 CONVOLVE, INC.   v. COMPAQ COMPUTER CORP.



       vice and [an] a seek acoustic noise level of
       the data storage device;
       operating the user interface so as to alter
       settings of one of the seek time and the
       seek acoustic noise level of the data stor-
       age device in inverse relation; and
       outputting commands to the data storage
       device causing the data storage device to
       alter seek trajectory shape by shaping in-
       put signals to the data storage device to
       reduce selected unwanted frequencies
       from a plurality of frequencies in accord-
       ance with the altered settings.
’473C1 patent col. 2 ll. 23–35 (reexamined claim 10).
    Convolve, Inc. (Convolve) filed suit against Seagate
Technology, LLC and Seagate Technology, Inc. (Seagate)
and Compaq Computer Corp. (Compaq) in July 2000,
alleging, among other things, infringement of the ’473
patent. See Convolve I, 527 F. App’x at 916. Seagate’s
accused products are disk drives with an on-board control-
ler that interfaces with a host computer. The controller
uses an industry standard interface, either ATA or SCSI,
and the parties group these together for purposes of this
appeal. The ATA/SCSI interface accepts commands from
the host computer processor to switch between a “quiet”
and a “performance” mode, and translates those com-
mands for the hard drive, instructing it to change seek
speed according to the selected mode. Compaq’s accused
products are computers that contain the F10 BIOS user
interface in combination with a Seagate hard drive. The
F10 BIOS is a graphical user interface that allows a user
to select certain hardware settings, including the seek
speed and acoustic noise of a Seagate hard drive, but does
not itself issue commands that directly change the seek
speed of the disk drives.
CONVOLVE, INC.   v. COMPAQ COMPUTER CORP.                5



    In March 2005, the district court issued a claim con-
struction order, which served the basis for its 2011 order
granting summary judgment. The district court held that
no accused products met the patent’s “selected unwanted
frequencies” limitation. We reversed, finding that issues
of fact precluded summary judgment of no direct or indi-
rect infringement. On remand, at the defendants’ re-
quest, the district court granted summary judgment on
three grounds: (1) Seagate’s ATA and SCSI interfaces do
not meet the “user interface” limitation because they
merely facilitate “[d]evice-to-device communications
involved in the subsequent execution of a user’s selected
mode,” J.A. 36; (2) Compaq’s computers do not meet the
“commands” limitation because the processor generating
the user interface does not itself generate the claimed
“commands,” J.A. 38–43; and, in the alternative, (3)
“patent infringement liability is precluded by intervening
rights arising from [a] December 2, 2008 substantive
amendment to the asserted claims,” J.A. 43. Convolve
appeals. We have jurisdiction under 28 U.S.C.
§ 1295(a)(1).
                             II
    This court reviews a district court’s decision concern-
ing summary judgment under the law of the regional
circuit. Grober v. Mako Prods., Inc., 686 F.3d 1335, 1344
(Fed. Cir. 2012). The Second Circuit reviews the grant or
denial of summary judgment de novo. Major League
Baseball Props., Inc. v. Salvino, Inc., 542 F.3d 290, 309
(2d Cir. 2008). “To prove literal infringement, the patent-
ee must show that the accused device contains each and
every limitation of the asserted claims.” Ericsson, Inc. v.
D-Link Sys., Inc., 773 F.3d 1201, 1215 (Fed. Cir. 2014).
When determining whether a patent is infringed, the
court must first “‘determine[ ] the scope and meaning of
the patent claims asserted,’ and then compare[ ] the
claims ‘to the allegedly infringing devices.’” Grober, 686
F.3d at 1344 (quoting Cybor Corp. v. FAS Techs., Inc., 138
6                  CONVOLVE, INC.   v. COMPAQ COMPUTER CORP.



F.3d 1448, 1454 (Fed. Cir. 1998)). To the extent review of
the district court’s claim construction is necessary, we
review the ultimate determination as to claim meaning de
novo, while giving deference to the district court’s factual
findings as to the claim scope. Teva Pharm. USA, Inc. v.
Sandoz, Inc., 135 S. Ct. 831, 836–38 (2015).
                              A
    The district court did not err in granting summary
judgment of no direct infringement to Seagate because
Seagate’s ATA/SCSI disk drives do not meet the “user
interface” limitation present in the asserted claims.
    In its 2005 Markman order, the district court con-
strued “user interface” as “software, hardware, firmware,
or a combination thereof that allows a person, directly or
indirectly, to alter parameters.” J.A. 96. In construing
the term, the court determined that a “user interface” is
not limited to a graphical user interface or mechanical
switches, which were both disclosed in the specification.
The court rejected a broader construction that would have
stated that the “user interface” “may be accessed via other
software or hardware, e.g., as a jumper, protocol, software
program, keyboard or mouse.” See J.A. 31 n.11. In reject-
ing that construction, the district court explained that
such an interpretation “fails to give meaning to the adjec-
tive ‘user,’ which distinguishes the interface from other
types of interfaces used in the computing field,” such as
“an advanced programming interface (API) which allows
one software program to ‘interface’ with another.”
J.A. 81. For the district court, “[t]he plain meaning of
‘user interface’ requires a user . . . .” Id. By including the
word “indirectly,” the district court intended to avoid
“pedantic arguments” that a graphical user interface is
not a “user interface” because the user must “position[ ]
the cursor on the screen using a mouse,” such that the
“user is interfacing with the mouse, and the mouse is
interfacing with the computer.” J.A. 81.
CONVOLVE, INC.   v. COMPAQ COMPUTER CORP.                   7



    Convolve takes issue with how the district court ap-
plied its construction in the summary judgment proceed-
ing. In the summary judgment order, the district court
stayed true to its construction, and rejected Convolve’s
attempt to “expand the ‘user’ aspect of the term to the
point of obsolescence.” J.A. 34. The court explained “[t]he
proper interpretation of this Court’s ‘user interface’ con-
struction limits the application of ‘indirectly’ to the man-
ner in which a user alters disk drive parameters by
communicating a command to the computer (through
some combination of software, hardware, and firmware),
and the manner in which the user’s command—once
received by the user interface—is executed.” J.A. 35. In
other words, “‘indirectly’ preserves nothing more than the
true relationship between the user and his actual act of
selection.” J.A. 36.
    We find that both the district court’s construction of
the term “user interface” and its application of that con-
struction were proper. The language of the claims sup-
ports the district court’s construction of “user interface” as
“the site at which a user actually selects an operating
mode.” J.A. 36. The claim term is “user interface,” not
just “interface.” The word “user” therefore must distin-
guish between different kinds of interfaces. In the
claimed method, the only action that a user takes is
selecting an operating mode. The “user interface” is thus
the interface that the user interacts with to select an
operating mode—not subsequent interfaces or compo-
nents that merely execute the user’s selection. As the
district court found, a construction of “user interface” that
includes a subsequent device-to-device interface involved
in the execution of a mode selection “effectively reads the
term ‘user’ out of the claim language.” J.A. 32.
    The specification confirms this reading. The specifica-
tion discloses several embodiments of a “user interface,”
all of which the user interacts with directly to select an
operation mode. The specification discloses five graphical
8                 CONVOLVE, INC.   v. COMPAQ COMPUTER CORP.



user interfaces, shown in the figures as computer screen
images with arrows or a sliding bar that a person manipu-
lates with a mouse to select seek speed. It also describes
a mechanical switch on the hard drive itself that a user
physically pushes to change the operation mode. Alt-
hough the claims are not limited to these particular
embodiments, the nature of these embodiments confirms
that a “user interface” must be the site at which the user
actually selects an operation mode.
     Convolve argues that the prosecution history shows
that it specifically broadened the asserted claims to
include Seagate’s hard drives. According to the file histo-
ry, the original claims recited a “graphical user interface”
or a “controller,” and Convolve amended this term to read
“user interface.” J.A. 1930–42. While these amendments
may be broadening in some sense (including not just
graphical user interfaces but mechanical interfaces, and
not just controllers but software interfaces), they do not
necessarily include the on-board interfaces on Seagate’s
hard drives. The only evidence that these amendments
were meant to encompass Seagate’s product is a declara-
tion by one of the inventors submitted in this litigation.
J.A. 1096, ¶ 96. This post-hoc explanation is not enough
to overcome the language of the claims and the disclo-
sures in the specification.
    Moreover, the district court’s clarified construction is
consistent with its reasoning in the 2005 Markman order.
The district court could not have intended “indirectly” to
bring post-selection interfaces within the scope of “user
interface.” Under this reading, the term “user interface”
would include an interface that facilitates purely device-
to-device communication—such as the ATA/SCSI inter-
face on Seagate’s hard drives. But the district court
specifically excluded device-to-device interfaces when it
declined to adopt Convolve’s proposed construction of
“user” as “a person or device that uses the user interface.”
J.A. 81.
CONVOLVE, INC.   v. COMPAQ COMPUTER CORP.                    9



     Turning to the application of the district court’s con-
struction to the facts of this case, we are not persuaded
that the district court erred in finding that Convolve
failed to raise an issue of material fact. ATA and SCSI
are both device-to-device interfaces that connect the disk
drive with the host computer processor.             See, e.g.,
J.A. 2176 ¶ 25; J.A. 4686 (ATA and SCSI are interfaces
“between host system and storage devices”). Indeed,
Convolve’s expert conceded that he could not change a
Seagate disk drive’s mode without “install[ing] it in a
computer” and using “some other tool that would facilitate
[him] or facilitate [his] communication with the drive to
alter settings.” J.A. 4181–82; J.A. 2176 ¶ 29. While it is
true that the user can interact through a series of inter-
mediaries, that is not the “pedantic-type” argument ruled
out by the district court’s original claim construction.
Convolve’s arguments on appeal collapse into a challenge
of the district court’s claim construction, and fail to identi-
fy an error in the court’s application of its correct con-
struction to the facts of the case. 1
     Lastly, our decision in Convolve I does not preclude
the district court’s construction of “user interface.” As an
initial matter, Convolve waived this argument by not
raising it below. See Golden Bridge Tech., Inc. v. Nokia,
Inc., 527 F.3d 1318, 1322 (Fed. Cir. 2008). To the extent
that the argument was implicitly raised below, we inter-
pret our own mandate de novo, Retractable Tech., Inc. v.
Becton Dickinson & Co., 757 F.3d 1366, 1369 (Fed. Cir
2014), and conclude that the prior mandate does not
control the claim construction at issue here. In Convolve
I, this court vacated summary judgment of non-



    1  A jury determination in a parallel proceeding in
the Eastern District of Texas applying a different claim
construction does not compel a different result. Cf. J.A.
5051–52; J.A. 5063–65.
10                 CONVOLVE, INC.   v. COMPAQ COMPUTER CORP.



infringement under an inducement theory, because con-
trary to the district court’s conclusion, the panel found
some evidence that Compaq and Seagate’s customers
operated their products in an infringing manner. Specifi-
cally, there was evidence that Compaq and Seagate
provided “specific tools, with attendant instructions, on
how to use the drives in an infringing way.” Convolve I,
527 F. App’x at 929. Convolve argues that the panel
essentially held that Seagate’s devices could meet the
“user interface” limitation by finding they could directly
infringe. But the panel did not address this precise
question. Moreover, it construed only one claim term, and
specified that “[n]o other claim construction is relevant to
the district court’s ruling on the claims of the ’473 patent.”
Id. at 926. This court’s opinion in Convolve I is not con-
trolling of the claim construction and summary judgment
issues here.
                              B
    The district court erred by granting summary judg-
ment that Compaq’s F10 BIOS interface does not meet
the “commands” limitation of the asserted claim. In its
summary judgment ruling, the district court treated all
asserted claims as having the same scope, and concluded
that the recited “commands” must be “shaped when
issued from the processor in order to satisfy the claim
limitation[s],” J.A. 42, and therefore Compaq’s F10 BIOS
interface cannot infringe because it itself does not issue
shaped commands. Implicit in this ruling is a claim
interpretation that requires a singular processor associat-
ed with the user interface that issues commands, and
excludes the existence of a second processor capable of
issuing those commands, such as one integrated into the
data storage device. This overlooks the differences among
the asserted claims.
    The parties agree that the accused Compaq F10 BIOS
interface issues generic commands, not “shaped com-
CONVOLVE, INC.   v. COMPAQ COMPUTER CORP.                 11



mands” as required by the claims. Neither party contest-
ed, at the district court or on appeal, the district court’s
2005 construction of “data storage device” as including a
device that “receives shaped commands from processor
which may be integrated into the drive.” J.A. 85. Like-
wise, neither party contests the district court’s construc-
tion of the term “outputting commands to the data storage
device” to encompass a situation where the command
originates from the device itself. J.A. 86. Consistent with
the specification’s disclosure of an embodiment where the
actuator seeks “in accordance with control signals re-
ceived from processor 73,” which may be a “‘separate
controller’ dedicated to the disk drive,” ’473 patent col. 10
ll. 6–14, these constructions together cover a disk drive
that receives the required “shaped commands” from an
on-board interface, rather than a separate computer
processor.
     Turning to the specifics of the claims, we look to three
groups. Claims 7, 8, and 10–14 do not plainly require the
“user interface” to perform the “outputting commands”
function. These claims require three core steps: “provid-
ing” a user interface, “operating” the user interface, and
“outputting commands.” See, e.g., ’473C1 patent col. 2 ll.
23–35 (reexamined claim 10). Although a user interface
component is the object of the first two steps, the third
step simply recites “outputting commands to the data
storage device,” without tying that outputting to a partic-
ular processor or to the antecedent user interface. See id.
The language of these claims does not, as the district
court assumed, require the user interface to issue the
“shaped commands” recited in the claims. This is con-
sistent with the court’s interpretation of the other claim
elements, and with the specification, which discloses an
embodiment where the shaped command originates from
the device itself, J.A. 86. Thus, it was error for the dis-
trict court to grant summary judgment for these claims.
12                 CONVOLVE, INC.   v. COMPAQ COMPUTER CORP.



    Claims 9 and 15 pose a greater challenge, however,
because they recite an apparatus comprising “a processor”
that executes certain process steps “to generate a user
interface,” “to alter settings in the user interface,” and “to
output commands to the data storage device.” See, e.g.,
’473C1 patent col 2 ll. 7–22 (reexamined claim 9). This
court has “repeatedly emphasized that an indefinite
article ‘a’ or ‘an’ in patent parlance carries the meaning of
‘one or more’ in open-ended claims containing the transi-
tional phrase ‘comprising.’” KCJ Corp. v. Kinetic Con-
cepts, Inc., 223 F.3d 1351, 1356 (Fed. Cir. 2000). 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). Thus, absent a clear intent in the
claims themselves, the specification, or the prosecution
history, we interpret “a processor” as “one or more proces-
sors.”
    Here, we find no such evidence clearly limiting “a pro-
cessor” to a singular processor. While it is true that the
patentee recited other claim terms in the plural, e.g.,
“output commands,” “alter settings,” or “input signals,”
this does not compel a departure from our general rule
that “a” means “one or more” when following the open-
ended term “comprising.” Such a conclusion is bolstered
by the specification’s plain disclosure of an embodiment
where “seeks” are controlled by a “separate controller
dedicated to the disk drive.” ’473 patent col. 10 ll. 6–14.
Thus, it was error for the district court to grant summary
judgment for these claims.
     Claims 1, 3, and 5, likewise, recite “a processor,” but
do so in the context of reciting the function of the “user
interface.” Specifically, claim 1 recites a “[u]ser interface
for . . . working with a processor . . . comprising:” a means
for controlling seek time on a data storage device, and a
“means for causing the processor to output commands to
the data storage device.” ’473C1 patent col. 1 ll. 22–37
CONVOLVE, INC.   v. COMPAQ COMPUTER CORP.               13



(reexamined claim 1). Here, unlike claims 9 and 15, the
language and structure of claim 1 demonstrate a clear
intent to tie the processor that “output[s] commands to
the data storage device” to the “user interface.” Specifi-
cally, claim 1 recites “a processor” in the preamble before
recitation of “comprising,” and the claim body uses the
definite article “the” to refer to the “processor.” This
reference to “the processor,” referring back to the “a
processor” recited in preamble, supports a conclusion that
the recited user interface is “operatively working with”
the same processor to perform all of the recited steps. In
other words, the claim language requires a processor
associated with the user interface to issue the shaped
commands of the claims. Given this claim language,
which contrasts with the claims described above that
allow for multiple processors, we conclude that claims 1,
3, and 5 require the user interface to work with a single
processor in performing all of the claim steps. Under this
construction, the Compaq computers do not meet each
limitation of the claims, because the “user interface”
processor does not send shaped commands to the hard
drive.
    On appeal, Compaq argues that in a 2008 reexamina-
tion, Convolve disclaimed a system in which a processor
other than the “user interface” processor performs the
“outputting commands” function. According to Compaq,
Convolve traversed an anticipation rejection based on the
“Ray Thesis” by arguing that, unlike the claimed inven-
tion, “the commands of Ray did not originate from a host
computer user interface.” J.A. 4218–19. We disagree.
The prosecution history does not clearly disclaim a system
in which a processor other than the “user interface”
processor issues the shaped commands. In the face of an
anticipation rejection based on the Ray Thesis, the pa-
tentee argued that the prior art does not disclose a host
processor at all, J.A. 5020, or a user interface that is in
any way involved in the “outputting commands” step—not
14                CONVOLVE, INC.   v. COMPAQ COMPUTER CORP.



that the Ray method lacks a user interface that itself
issues “outputting commands,” see J.A. 5021. And the
examiner agreed that “Ray does not disclose a host pro-
cessor running a user interface . . . .” J.A. 4219.
    To the extent the examiner suggested in a later office
action that “the user interface runs on the processor of the
host computer, but not on the processor of the disk drive,”
the applicant objected and argued that the ’473 patent
discloses that “the user interface can run (i) on the pro-
cessor of the host computer, (ii) on the processor of the
disk drive, (iii) or both.” J.A. 5046. The examiner subse-
quently allowed the claims. Although there is some
evidence that the examiner also understood the claims to
require that all functions occur on a user interface “run-
ning on the processor external to the data storage device,”
J.A. 4218–19, it is not clear from the record that allow-
ance was based on this understanding, or that the patent-
ee disclaimed this claim scope. Thus, we conclude that
the district court did not err in granting summary judg-
ment that Compaq’s F10 BIOS does not meet the “com-
mands” limitation in claims 1, 3, and 5. But, we find the
district court erred by interpreting the remaining assert-
ed claims as requiring the processor associated with the
user interface to also generate the claimed commands.
                             III
    Having concluded that the district court erred in
granting summary judgment of non-infringement with
respect to the “commands” limitation, we turn to the
intervening rights inquiry. “A patentee of a patent that
survives reexamination is only entitled to infringement
damages for the time period between the date of issuance
of the original claims and the date of the reexamined
claims if the original and the reexamined claims are
‘substantially identical.’” R & L Carriers, Inc. v. Qual-
comm, Inc., 801 F.3d 1346, 1351 (Fed. Cir. 2015) (quoting
35 U.S.C. § 252 (2012)). “[I]t is the scope of the claim that
CONVOLVE, INC.   v. COMPAQ COMPUTER CORP.                 15



must be identical, not that identical words must be used.”
Slimfold Mfg. Co., Inc. v. Kinkead Indus., Inc., 810 F.2d
1113, 1116 (Fed. Cir. 1987). As a result, amendments
made during reexamination do not necessarily compel a
conclusion that the scope of the claims has been substan-
tively changed. See, e.g., Bloom Eng’g Co., 129 F.3d at
1250 (“There is no absolute rule for determining whether
an amended claim is legally identical to an original
claim.”). This is true even where the claims at issue were
amended during reexamination after a rejection based on
prior art. Laitram Corp. v. NEC Corp., 952 F.2d 1357,
1362–63 (Fed. Cir. 1991) (“Laitram I”); see also R&L
Carriers, 801 F.3d at 1350–51 (emphasizing that the
reasoning for the amendment does not matter; the focus is
on the scope of the claims). Rather, “[t]o determine
whether a claim change is substantive it is necessary to
analyze the claims of the original and the reexamined
patents in light of the particular facts, including the prior
art, the prosecution history, other claims, and any other
pertinent information.” Laitram I, 952 F.2d at 1362–63.
    In determining the scope of the claims, we apply the
traditional claim construction principles of Phillips v.
AWH Corp., 415 F.3d 1303 (Fed. Cir. 2005) (en banc),
paying particular attention to the “examiner’s focus in
allowing the claims” after amendment. R & L Carriers,
801 F.3d at 1351; see also Laitram Corp. v. NEC Corp.,
163 F.3d 1342, 1348 (Fed. Cir. 1998) (Laitram IV) (When
an amendment is made during the reexamination pro-
ceedings to overcome a prior art rejection, that is a “high-
ly influential piece of prosecution history.”). On appeal,
we “review the district court’s subsidiary factual findings
on the scope of the reexamined and original claims for
clear error, but the ultimate conclusion regarding the
scope of the claims de novo.” R & L Carriers, 801 F.3d at
1350 (citing Teva, 135 S. Ct. at 841–42).
    In this case, the patentee added the modifier “seek” in
front of “acoustic noise” during the 2008 reexamination
16                 CONVOLVE, INC.   v. COMPAQ COMPUTER CORP.



proceedings after a prior art rejection. Our task, there-
fore, is to determine whether the pre-2008 reexamination
claims are limited to “seek acoustic noise” or whether the
original claims cover both seek and spindle acoustic noise.
Applying the Phillips framework, we conclude that the
claims were originally limited to seek acoustic noise, and
the addition of the word “seek” did not alter the scope of
the claims.
                              A
    The proper claim construction is “the meaning that
the term would have to a person of ordinary skill in the
art in question at the time of the invention, i.e., as of the
effective filing date of the patent application.” Phillips,
415 F.3d at 1313. The specification “is the single best
guide to the meaning of a disputed term” and is usually
“dispositive.” Id. at 1315 (citation omitted). On their
face, the original claims recite only “acoustic noise,” which
could encompass any manner of acoustic noise, including
that generated from the spindle. But when read in con-
junction with the remaining claim limitations and in light
of the specification and prosecution history, a person of
ordinary skill in the art would understand the claims to
be limited to seek acoustic noise.
     The specification does not use the term “seek acoustic
noise” or expressly exclude acoustic noise generated by
spindle rotation, and, at some points, it teaches that
acoustic noise can arise from more than one type of vibra-
tion. See, e.g., ’473 patent col. 2 ll. 5–10; id. at col. 9 ll.
60–67. However, the focus of the specification is on the
seek process and the noise it generates. For example, the
specification states that “the present invention” is di-
rected to employing a “dynamic system” to “reduc[e]
unwanted vibrations, which, if unchecked, could lead to
disk read/write errors or excessive noise.” Id. at col. 1
ll. 15–20. And the only vibrations and noise described in
the Background section are those caused by the move-
CONVOLVE, INC.   v. COMPAQ COMPUTER CORP.                   17



ment of the disk drive’s seek arm—nowhere in the Back-
ground or elsewhere in the specification is mention made
of noise caused by spindle motor operation or any other
form of acoustic noise. See, e.g., ’473 patent col. 1 ll. 28–
36; id. at col. 19 ll. 6–32 (describing vibration and acoustic
noise caused by movement of the seek arm).
    This understanding is reinforced by other claim limi-
tations. For example, the claims expressly tie “acoustic
noise” to “seek time” by reciting settings for “seek time”
and “acoustic noise” “in inverse relation.” See, e.g., J.A.
154 (claim 10). Although not explicit in the claims, the
specification makes clear that changes in “seek time”
result only from increasing or decreasing the speed at
which the arm in the hard drive moves from track-to-
track. See ’473 patent col. 1 ll. 39–43 (“The drive’s seek
time comprises the time it takes for the drive’s head to
come to rest at a position where the head can perform a
read/write operation on a particular track.”); see also id.
at col. 6 l. 65–col. 7 l. 3 (“Disk drive noise level and seek
time vary inversely along the continuum, meaning that,
as the noise level of the disk drive progressively increases,
the seek time of the disk drive progressively decreases.
Likewise, as the noise level of the disk drive progressively
decreases, the seek time of the disk drive progressively
increases.”); id. at col. 7 ll. 31–35 (“[T]here is an effective
trade-off between seek time and noise level, meaning that
as seek time increases, noise level decreases and vice
versa.”). To be sure, changes in spindle rotation speed,
which generate acoustic noise, may affect the time needed
to read the storage device. But read time is a separate
concept from seek time. There is no evidence in the
record from which we can conclude that a reduction in
spindle speed is in any way connected to seek speed.
Seagate thus cannot show that there is any relation
between “seek time” and acoustic noise other than the
noise generated by the movement of the seek arm.
18                CONVOLVE, INC.   v. COMPAQ COMPUTER CORP.



    Lastly, the “outputting commands” step of the claimed
method further suggests that the claims are limited to
seek acoustic noise. This step requires outputting com-
mands that “alter seek trajectory shape . . . to reduce
unwanted frequencies . . . in accordance with the altered
settings.” In other words, one means of reducing the
claimed “acoustic noise” is specifically directed to the seek
process (seek trajectory shape) and the “unwanted fre-
quencies” associated with that process.
                             B
    While the specification, in and of itself, may not re-
quire the “seek acoustic noise” construction, the prosecu-
tion history of the ’473 patent before the 2008
reexamination demonstrates that acoustic noise is limited
to “seek” acoustic noise. In an office action dated March
26, 2001, the Patent Office rejected several of the claims
as anticipated or obvious in light of two prior art refer-
ences: Rowan and Koizumi. The Patent Office determined
that Rowan teaches a mechanism for controlling seek
time and both electrical noise and acoustic noise from the
spindle motor, J.A. 1893, and that Koizumi teaches
“reduc[ing] the spindle speed to achieve the quiet mode,”
J.A. 1896. In response, on April 2, 2001, the patentee
amended the claims “to state explicitly that the noise to
be controlled is acoustic noise as opposed to electrical
noise.” J.A. 1909. In explaining the reasoning for the
amendment, the applicant went further and made clear
that the acoustic noise problems addressed by the claims
and the specification are limited to those generated by the
seek function, not the spindle motor. See J.A. 1910 (ex-
plaining that “as now claimed, it is the acoustic noise level
of the data storage device that is controlled by changing
seek trajectory shape to reduce unwanted frequencies by
shaping input signals to the data storage device”). The
applicant also emphasized that “the acoustic noise reduc-
tion taught by Rowan deals only with control of the spin-
dle motor, not with control of seek.” J.A. 1910. As for the
CONVOLVE, INC.   v. COMPAQ COMPUTER CORP.                19



combination of Rowan and Koizumi, the applicant argued
that the combination fails to render obvious the claimed
invention because “the acoustic noise reduction technique
of Rowan . . . involves altering control of only the spindle
motor to reduce acoustic noise.” J.A. 1911. And there
would be no motivation to combine Koizumi, which “re-
duced the spindle speed to achieve the quiet mode,” “with
a reference that modifies the seek operation as opposed to
spindle speed to reduce noise.” J.A. 1912.
    To the extent the specification alone does not limit the
claims to seek acoustic noise, these prosecution history
statements show a clear intent to limit the scope of the
claims to seek acoustic noise—i.e., acoustic noise generat-
ed by the movement of the drive’s arm and read/write
head during the seek process. We note further that the
appellees themselves submitted a proposed construction
for the term “acoustic noise level of the data storage
device” that expressly excluded “audible noise emanating
from the spindle motor of the ‘data storage device.’” J.A.
656.
                             C
    The prosecution history of the 2008 reexamination—a
“highly influential” piece of evidence in the intervening
rights inquiry, Laitram IV, 163 F.3d at 1348—does not
compel a different result. Applying the broadest reasona-
ble interpretation, the examiner focused exclusively on
the language of the claims at the expense of the clear
language in the specification and prior examination
history. Indeed, the examiner stated that under the
broadest reasonable interpretation standard “limitations
are not read into the claims” and expressly rejected the
patentee’s attempt to interpret the claims in light of the
specification. See, e.g., J.A. 4932 (“In summary, the
examiner submits that Patent owners have set forth
narrow arguments, and relying largely on elements found
20                CONVOLVE, INC.   v. COMPAQ COMPUTER CORP.



only in the ’473 specification, that are more specific than
required by the broad limitations of the claims.”).
     In the intervening rights analysis, our task is to in-
terpret the scope of the claims per the Phillips standard,
see Laitram IV, 163 F.3d at 1346–47, and under the
correct standard, the specification “is the single best guide
to the meaning of the disputed term,” and is usually
dispositive, Phillips, 415 F.3d at 1313. “In addition to
consulting the specification, we have held that a court
should also consider the patent’s prosecution history, if it
is in evidence.” Id. at 1317 (citations and internal quota-
tion marks omitted). Thus, the examiner’s finding under
the broadest reasonable interpretation that the claims are
not limited to “seek acoustic noise” cannot be dispositive.
To the extent that the district court adopted this reason-
ing wholesale without accounting for the differences
between the broadest reasonable interpretation standard
and Phillips, the court erred.
     In sum, we conclude that the addition of the term
“seek” before “acoustic noise” did not alter the scope of the
claim. In so concluding, we decline to give significant
weight to the patentee’s and the examiner’s use of the
term “clarify” or “clarifying” in describing the amendment
in prosecution. The inquiry must focus on a case-by-case
analysis of the scope of the claims before and after claim
amendment, which gives rise to the intervening rights
challenge. See Laitram I, 952 F.2d at 1360–61 (rejecting
a per se rule and emphasizing that each case is decided on
its facts). Here, the language of the claims, read in light
of the specification and prosecution history, especially the
applicant’s 2001 remarks and amendment, compel a
conclusion that the claims as originally drafted were
limited to seek acoustic noise despite the lack of an ex-
press recitation in the claims.
CONVOLVE, INC.   v. COMPAQ COMPUTER CORP.                  21



                             IV
    In Convolve I, Compaq argued that the accused prod-
ucts do not maintain an inverse relationship between seek
time and acoustic noise for all seeks, regardless of length,
as required by the claims. We declined to reach that
argument and left “those questions . . . to the trial court in
the first instance.” Convolve I, 527 F. App’x at 932.
Compaq again raised the argument below, and again the
district court declined to reach it. J.A. 24–25. And again
on appeal, Compaq asks this court to rule in the first
instance on its “inverse relationship” argument. But for
the same reasons articulated in Convolve I, we decline to
do so. The district court may consider this issue on re-
mand.
                              V
    For the reasons discussed above, we affirm the district
court’s grant of summary judgment that Seagate’s
ATA/SCSI hard drives do not infringe the asserted claims
because they do not meet the user interface limitation of
the claims. Likewise, we affirm the district court’s grant
of summary judgment of non-infringement by Compaq’s
accused products as to claims 1, 3, and 5 because Com-
paq’s F10 BIOS does not meet the “commands” limitation
of those claims. But we vacate the court’s grant of sum-
mary judgment of non-infringement by Compaq’s accused
products as to claims 7–15 because the F10 BIOS does
meet the “commands” limitation. Finally, because the
addition of the term “seek” in reexamination did not alter
the scope of the claims, we reverse the district court’s
grant of summary judgment of non-infringement based on
its determination that liability is precluded by interven-
ing rights.
     AFFIRMED-IN-PART, VACATED-IN-PART,
      REVERSED-IN-PART, AND REMANDED
    No costs.
