  United States Court of Appeals
      for the Federal Circuit
                ______________________

            INTERVAL LICENSING LLC,
                Plaintiff-Appellant,

                           v.

                      AOL, INC.,
                  Defendant-Appellee,

                         AND

                    APPLE, INC.,
                  Defendant-Appellee,

                         AND

                   GOOGLE, INC.,
                  Defendant-Appellee,

                         AND

                    YAHOO! INC.,
                  Defendant-Appellee.
                ______________________

             2013-1282, -1283, -1284, -1285
                ______________________

   Appeals from the United States District Court for the
Western District of Washington in Nos. 13-CV-0263, 13-
CV-0264, 13-CV-0265 and 13-CV-0266, Judge Marsha J.
Pechman.
                ______________________
2                       INTERVAL LICENSING LLC   v. AOL, INC.




              Decided: September 10, 2014
                ______________________

    THOMAS C. GOLDSTEIN, Goldstein & Russell, PC, of
Washington, DC, argued for plaintiff-appellant. Of coun-
sel on the brief were MICHAEL HEIM, NATHAN J. DAVIS,
and DOUGLAS R. WILSON, Heim, Payne & Chorush LLP, of
Houston, Texas; JUSTIN A. NELSON, Susman Godfrey
L.L.P., of Seattle, Washington, and MAX L. TRIBBLE, JR.,
of Houston, Texas.

     J. MICHAEL JAKES, Finnegan, Henderson, Farabow,
Garrett & Dunner, LLP, of Washington, DC, argued for
all defendants-appellees. With him on the brief were
GERALD F. IVEY, CORTNEY S. ALEXANDER, ROBERT L.
BURNS, II, and ERIK R. PUKNYS, for AOL Inc.; ELIZABETH
DAY, DAVID ALBERTI, and MARC C. BELLOLI, Feinberg Day
Alberti & Thompson LLP, of Menlo Park, California, and
BRIAN BERLINER, O’Melveny & Myers, LLP, of Los Ange-
les, California, for Apple Inc.; WARREN S. HEIT, CARMEN
LO, and WENDI R. SCHEPLER, White & Case LLP, of Palo
Alto, California, and KEVIN MCGANN and DIMITRIOS T.
DRIVAS, of New York, New York, for Google Inc.; and
DEANNE MAYNARD, Morrison & Foerster LLP, of Washing-
ton, DC, and MICHAEL A. JACOBS and MATTHEW I.
KREEGER, of San Francisco, California, for Yahoo! Inc.
                   ______________________

        Before TARANTO and CHEN, Circuit Judges. ∗




    ∗
        Randall R. Rader, who retired from the position of
Circuit Judge on June 30, 2014, did not participate in this
decision.
INTERVAL LICENSING LLC   v. AOL, INC.                     3



CHEN, Circuit Judge.
    Interval Licensing LLC (“Interval”) appeals from four
stipulated final judgment orders of the United States
District Court for the Western District of Washington. 1
Each order granted: (1) final judgment of invalidity of
claims 4–8, 11, 34, and 35 of U.S. Patent 6,034,652 (“the
’652 patent”) and claims 1–4 and 7–15 of U.S. Patent
6,788,314 (“the ’314 patent”), based on the court’s deter-
mination that those claims are indefinite; and (2) final
judgment of non-infringement of claims 15–18 of the ’652
patent, based on the court’s claim construction of the
phrase “during operation of an attention manager.” While
we agree with the court’s indefiniteness determination,
we do not agree with the court’s construction of “attention
manager” and thus modify that construction. Additional-
ly, we modify the court’s construction of the term “instruc-
tions.” For the reasons set forth below, we affirm the
judgments of invalidity, vacate the judgments of non-
infringement, and remand for further proceedings.
                       BACKGROUND
    The ’652 and ’314 patents are directed to an “attention
manager for occupying the peripheral attention of a
person in the vicinity of a display device.” The patents,
which share a common specification, describe a system
that acquires data from a content provider, schedules the
display of the content data, generates images from the
content data, and then displays the images on a device.



   1    Interval sued the four appellees for infringement
in the district court. Due to complicated procedural
reasons not relevant here, the court severed all of the
claims and counterclaims into four cases, issuing separate
final judgment orders of invalidity and non-infringement
for each case. Interval appealed each order, and the four
appeals were consolidated into the present appeal.
4                        INTERVAL LICENSING LLC   v. AOL, INC.



The patents explain that the term “image” is used “broad-
ly here to mean any sensory stimulus that is produced
from the set of content data, including, for example, visual
imagery (e.g., moving or still pictures, text, or numerical
information) and audio imagery (i.e., sounds).” ’652
patent, 6:60–64. The content data presented in the imag-
es are “virtually limitless,” and may include advertise-
ments, video nature scenes, and radio talk shows. Id. at
7:26–38. As for the users of the attention manager, the
patents contemplate that the system will typically occupy
the attention of human users, but may also be used to
occupy the attention of dogs, cats, and parrots. See id. at
29:32–40. The primary issues raised on appeal center on
the manner in which the patented invention displays
content data—specifically, how the attention manager
displays “images” so as to attract the peripheral attention
of the user.
    To engage the “peripheral attention” of a user in “the
vicinity of a display device,” the attention manager
“[g]enerally . . . makes use of ‘unused capacity’ of the
display device.” Id. at 2:3–9. The specification discloses
two primary approaches to utilizing “unused capacity.”
First, the specification describes a “screen saver embodi-
ment” that displays images “automatically after detection
of an idle period” or after activation of the screen saver by
the user. Id. at 3:19–22, 9:24–36. The patents use screen
savers—typically used for preventing screen burnout and
for “aesthetic or entertainment value”—for the purpose of
“display[ing] content from a remote location via a comput-
er network.” Id. at 1:39–67. The screen saver embodi-
ment may be employed “while a primary interaction is
ongoing, but during inactive periods (i.e., when the user is
not engaged in an intensive interaction with the appa-
ratus).” Id. at 6:35–38.
    Second, the specification describes a wallpaper em-
bodiment. “Wallpaper,” the specification explains, is “a
pattern generated in the background portions on a com-
INTERVAL LICENSING LLC   v. AOL, INC.                     5



puter display screen.” Id. at 1:51–52. The patents’ “wall-
paper embodiment” displays images “while the user is
engaged in a primary interaction with the apparatus,
which primary interaction can result in the display of an
image or images in addition to the image or images gen-
erated from the set of content data.” Id. at 3:25–31. The
wallpaper embodiment makes use of the “unused” spatial
capacity of a screen, displaying information in areas not
used by the user’s primary interaction. Id. at 6:38–51.
    On August 27, 2010, Interval sued AOL Inc., Apple
Inc., Google Inc., and Yahoo! Inc. (the “Defendants”) in the
Western District of Washington, alleging infringement of
four patents, including the ’652 and ’314 patents. Inter-
val’s suit alleged that the Defendants infringe the patents
through products and software that use “pop-up” notifica-
tions to present information to users. In early 2011, two
of the Defendants filed a request for ex parte reexamina-
tion of the ’652 patent, while another defendant filed a
request for inter partes reexamination of the ’314 patent.
The district court stayed the litigation pending the
USPTO’s reexaminations. Examiners found the asserted
claims of both patents to be patentable in view of the cited
prior art. 2 The district court then lifted the stay with
respect to the ’652 and ’314 patents, proceeding to claim
construction.
   Of the twenty-five claims Interval asserted in the ’652
and ’314 patents, all but four contain or depend on the


   2    After the present appeal was argued, the Patent
Trial and Appeal Board reversed the examiner’s decision
of the inter partes reexamination of the ’314 patent. The
Board rejected all of the asserted claims of the ’314 patent
as obvious, anticipated, or both. See Apple, Inc. v. Inter-
val Licensing LLC, No. 2013-005424, 2014 WL 1322685,
at *16 (Patent Tr. & App. Bd. Apr. 1, 2014). Interval has
indicated that it intends to appeal the Board’s decision.
6                       INTERVAL LICENSING LLC   v. AOL, INC.



phrase “in an unobtrusive manner that does not distract a
user.” Claim 1 of the ’314 patent is representative:
    A method for engaging the peripheral attention of
      a person in the vicinity of a display device,
      comprising the steps of:
      providing one or more sets of content data to a
        content display system associated with the
        display device and located entirely in the
        same physical location as the display device;
      providing to the content display system a set of
        instructions for enabling the content display
        system to selectively display, in an unob-
        trusive manner that does not distract a
        user of the display device or an appa-
        ratus associated with the display device
        from a primary interaction with the
        display device or apparatus, an image
        or images generated from a set of con-
        tent data; and
      auditing the display of sets of content data by
        the content display system;
      wherein the one or more sets of content data
        are selected from a plurality of sets of con-
        tent data, each set being provided by an as-
        sociated content provider, wherein each
        associated content provider is located in a
        different physical location than at least one
        other content provider and each content pro-
        vider provides its content data to the content
        display system independently of each other
        content provider and without the content da-
        ta being aggregated at a common physical lo-
        cation remote from the content display
        system prior to being provided to the content
        display system, and wherein for each set the
INTERVAL LICENSING LLC   v. AOL, INC.                      7



         respective content provider may provide
         scheduling instructions tailored to the set of
         content data to control at least one of the du-
         ration, sequencing, and timing of the display
         of said image or images generated from the
         set of content data.
’314 patent, 29:53–30:18 (emphasis added).
    Although all of the asserted claims in the ’314 patent
depend on the “unobtrusive manner” language, four of the
asserted claims in the ’652 patent do not. Representative
claim 15 recites:
   A computer readable medium encoded with one or
     more computer programs for enabling acquisi-
     tion of a set of content data and display of an
     image or images generated from the set of con-
     tent data on a display device during opera-
     tion of an attention manager, comprising:
      acquisition instructions for enabling acquisition
        of a set of content data from a specified in-
        formation source;
      user interface installation instructions for ena-
        bling provision of a user interface that allows
        a person to request the set of content data
        from the specified information source;
      content data scheduling instructions for provid-
        ing temporal constraints on the display of
        the image or images generated from the set
        of content data, wherein the content data
        scheduling instructions further comprise se-
        quencing instructions that specify an order
        in which the images generated from a set of
        content data are displayed; and
8                         INTERVAL LICENSING LLC   v. AOL, INC.



        display instructions for enabling display of the
           image or images generated from the set of
           content data.
’652 patent, 32:37–58 (emphasis added).
    In its claim construction order, the district court
found that “the terms ‘in an unobtrusive manner’ and
‘does not distract’ a user, whether used together or sepa-
rately,” 3 are indefinite. Interval Licensing, LLC v. AOL,
Inc., C10-1385MJP, 2013 WL 792791, at *3 (W.D. Wash.
Feb. 28, 2013). After reviewing the claim language, the
written description, and the prosecution history, the
district court offered two primary reasons for holding the
claim language indefinite: (1) “because the patents fail to
provide an objective standard by which to define the scope
of [the ‘unobtrusive manner’ phrase]”; and (2) “because
the determination of whether an accused product would
meet the claim limitations depends on its usage in chang-
ing circumstances.” Id. at *5.
    The district court also construed several disputed
claim terms. Relevant here, the court construed the term
“attention manager” as limited to the specific screensaver
and wallpaper embodiments. See id. at *10–11 (adopting
Defendants’ construction of “a system that displays imag-
es to a user either when the program detects that the user
is not engaged in a primary interaction or as a back-
ground of the computer screen”). The court also adopted



    3   As Interval observes, much of the district court’s
indefiniteness analysis treats “unobtrusive manner” and
“does not distract a user” as distinct claim limitations.
Interval argues that “[b]ecause the phrase is used as a
whole repeatedly throughout the specification and
claims . . . all of the words of the phrase should be con-
strued together.” Appellant’s Br. 28 n.5. We agree and
evaluate the phrase accordingly in this opinion.
INTERVAL LICENSING LLC   v. AOL, INC.                       9



the Defendants’ construction of “instructions,” a term
which appears in many of the asserted claims. See id. at
*15–16 (construing “instructions” as “a statement in a
programming language that specifies a function to be
performed by a system”).
    Based on the claim construction order, the parties
stipulated that twenty-one claims in both patents were
invalid as indefinite, and that claims 15–18 of the ’652
patent were not infringed by the Defendants. On Febru-
ary 18, 2013, the district court issued final judgment
orders to that effect, which Interval timely appeals.
Interval asks us to reverse the district court’s holding that
the claim phrase “in an unobtrusive manner that does not
distract a user” is indefinite, 4 vacate the court’s construc-
tion of “attention manager,” and clarify the court’s con-
struction of “instructions.”




    4    The district court separately addressed independ-
ent claim 4 of the ’652 patent, which uses the “unobtru-
sive manner” phrase in a means-plus-function limitation.
See ’652 patent, 30:29–33 (claiming a “means for selective-
ly displaying on the display device, in an unobtrusive
manner that does not distract a user”). The court held
that claim 4 and its dependent claims were indefinite
because the specification does not disclose an algorithm
that would constitute sufficient structure for accomplish-
ing the recited function. Interval, 2013 WL 792791, at *9.
Interval asks us to reverse that holding. However, be-
cause we affirm the district court’s determination that the
“in an unobtrusive manner that does not distract a user”
phrase is indefinite under 35 U.S.C. § 112, ¶ 2 for the
reasons stated in this opinion, we find it unnecessary to
address the district court’s additional determination that
the means-plus-function claims are indefinite due to a
lack of corresponding structure in the specification.
10                         INTERVAL LICENSING LLC   v. AOL, INC.



    We have      jurisdiction   pursuant    to   28     U.S.C.
§ 1295(a)(1).
                          DISCUSSION
                     I.   Indefiniteness
    A patent must “conclude with one or more claims par-
ticularly pointing out and distinctly claiming the subject
matter which the applicant regards as [the] invention.”
35 U.S.C. § 112, ¶ 2 (2006). 5 A claim fails to satisfy this
statutory requirement and is thus invalid for indefinite-
ness if its language, when read in light of the specification
and the prosecution history, “fail[s] to inform, with rea-
sonable certainty, those skilled in the art about the scope
of the invention.” Nautilus, Inc. v. Biosig Instruments,
Inc., 134 S. Ct. 2120, 2124 (2014). We review the district
court’s indefiniteness determination here de novo. See
Wellman, Inc. v. Eastman Chem. Co., 642 F.3d 1355, 1365
(Fed. Cir. 2011); Young v. Lumenis, Inc., 492 F.3d 1336,
1344 (Fed. Cir. 2007). 6




     5   Paragraph 2 of 35 U.S.C. § 112 was replaced with
newly designated § 112(b) when § 4(c) of the America
Invents Act (“AIA”), Pub. L. No. 112-29, took effect on
September 16, 2012. Because the applications resulting
in the patents at issue in this case were filed before that
date, we will refer to the pre-AIA version of § 112.
    6    We note that the district court’s indefiniteness de-
termination rests only on intrinsic evidence, and that
there are no disputes about underlying questions of fact.
Although the Defendants point to the testimony of Inter-
val’s expert in support of their argument that the “unob-
trusive manner” phrase is indefinite, see Appellee’s Br. 32,
we find it unnecessary to rely on that testimony (or any
other extrinsic evidence) to reach our conclusion. Like the
district court, we find the claims indefinite based on the
INTERVAL LICENSING LLC   v. AOL, INC.                    11



                              A
    After the present appeal was argued, the Supreme
Court issued its opinion in Nautilus, Inc. v. Biosig In-
struments, Inc., which addressed our use of the expres-
sions “insolubly ambiguous” and “amenable to
construction” in applying § 112, ¶ 2. The Court explained
that the statute’s definiteness requirement calls for a
“delicate balance.” Nautilus, 134 S. Ct. at 2128 (quoting
Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co.,
Ltd., 535 U.S. 722, 731 (2002)). The definiteness standard
“must allow for a modicum of uncertainty” to provide
incentives for innovation, but must also require “clear
notice of what is claimed, thereby appris[ing] the public of
what is still open to them.” Id. at 1228, 1229 (internal
citations omitted). In light of that balance, the Court
characterized our “insolubly ambiguous” and “amenable
to construction” expressions as “more amorphous than the
statutory definiteness requirement allows.” Id. at 2131.
What the statute requires, the Court clarified, “is that a
patent’s claims, viewed in light of the specification and
prosecution history, inform those skilled in the art about
the scope of the invention with reasonable certainty.” Id.
at 2129.
    The key claim language at issue in this appeal in-
cludes a term of degree (“unobtrusive manner”). We do
not understand the Supreme Court to have implied in
Nautilus, and we do not hold today, that terms of degree
are inherently indefinite. Claim language employing
terms of degree has long been found definite where it
provided enough certainty to one of skill in the art when
read in the context of the invention. See, e.g., Eibel Pro-
cess Co. v. Minnesota & Ontario Paper Co., 261 U.S. 45,
65–66 (1923) (finding “substantial pitch” sufficiently


claims, the written description, and the prosecution
history.
12                       INTERVAL LICENSING LLC   v. AOL, INC.



definite because one skilled in the art “had no difficul-
ty . . . in determining what was the substantial pitch
needed” to practice the invention). As the Supreme Court
recognized in Nautilus, “absolute precision” in claim
language is “unattainable.” 134 S. Ct. at 2129; see also
Enzo Biochem, Inc. v. Applera Corp., 599 F.3d 1325, 1335
(Fed. Cir. 2010) (holding that the claim phrase “not inter-
fering substantially” was not indefinite even though the
construction “define[d] the term without reference to a
precise numerical measurement”); Invitrogen Corp. v.
Biocrest Mfg., L.P., 424 F.3d 1374, 1384 (Fed. Cir. 2005)
(“[A] patentee need not define his invention with mathe-
matical precision in order to comply with the definiteness
requirement.”).
    Although absolute or mathematical precision is not
required, it is not enough, as some of the language in our
prior cases may have suggested, to identify “some stand-
ard for measuring the scope of the phrase.” See Appel-
lant’s Br. 31 (quoting Datamize, LLC v. Plumtree
Software, Inc., 417 F.3d 1342, 1351 (Fed. Cir. 2005)). The
Supreme Court explained that a patent does not satisfy
the definiteness requirement of § 112 merely because “a
court can ascribe some meaning to a patent’s claims.”
Nautilus, 134 S. Ct. at 2130. The claims, when read in
light of the specification and the prosecution history, must
provide objective boundaries for those of skill in the art.
See id. at 2130 & n.8 (indicating that there is an indefi-
niteness problem if the claim language “might mean
several different things and ‘no informed and confident
choice is available among the contending definitions’”
(quoting Every Penny Counts, Inc. v. Wells Fargo Bank,
N.A., __ F. Supp. 2d __, 2014 WL 869092, at *4 (M.D. Fla.
Mar. 5, 2014)); see also Halliburton Energy Servs., Inc. v.
M-I LLC, 514 F.3d 1244, 1251 (Fed. Cir. 2008) (“The fact
that [the patent holder] can articulate a definition sup-
ported by the specification . . . does not end the inquiry.
Even if a claim term’s definition can be reduced to words,
INTERVAL LICENSING LLC   v. AOL, INC.                      13



the claim is still indefinite if a person of ordinary skill in
the art cannot translate the definition into meaningfully
precise claim scope.”).
                              B
    The patents’ “unobtrusive manner” phrase is highly
subjective and, on its face, provides little guidance to one
of skill in the art. Although the patented invention is a
system that displays content, the claim language offers no
objective indication of the manner in which content imag-
es are to be displayed to the user. As the district court
observed, “whether something distracts a user from his
primary interaction depends on the preferences of the
particular user and the circumstances under which any
single user interacts with the display.” Interval, 2013 WL
792791, at *4. The lack of objective boundaries in the
claim language is particularly troubling in light of the
patents’ command to read “the term ‘image’ . . . broadly to
mean any sensory stimulus that is produced from the set
of content data,” including sounds and video. ’652 patent,
6:60–64. The patents contemplate a variety of stimuli
that could impact different users in different ways. As we
have explained, a term of degree fails to provide sufficient
notice of its scope if it depends “on the unpredictable
vagaries of any one person’s opinion.” Datamize, 417 F.3d
at 1350.
    Where, as here, we are faced with a “purely subjec-
tive” claim phrase, we must look to the written descrip-
tion for guidance. Id. at 1351; see also Chimie v. PPG
Indus., Inc., 402 F.3d 1371, 1377 (Fed. Cir. 2005). We
find, however, that sufficient guidance is lacking in the
written description of the asserted patents.
                               i
    Interval contends that the “unobtrusive manner”
phrase is sufficiently defined through its relationship to
one of the two primary embodiments. The phrase, Inter-
14                       INTERVAL LICENSING LLC   v. AOL, INC.



val maintains, is tied exclusively to the wallpaper embod-
iment, thus informing those of skill in the art that “unob-
trusive” has only a spatial meaning in the context of the
patents. “Because the district court failed to appreciate
that the language describing display ‘in an unobtrusive
manner that does not distract a user’ is tied to specific
type of display described in the specification,” Interval
argues, the district court “improperly divorced its analysis
from the context of the written description and incorrectly
focused on irrelevant hypotheticals . . . .” Appellant’s Br.
23.
    We do not agree with Interval that it is reasonably
clear that the “unobtrusive manner” language is tied to a
specific type of display. Although Interval identifies
portions of the specification that appear to use the “unob-
trusive manner” phrase in conjunction with the wallpaper
embodiment, see ’652 patent, 2:12–19, 13:11–14, other
portions of the specification suggest that the phrase may
also be tied to the screen saver embodiment.
     According to one aspect of the invention, an atten-
     tion manager engages the peripheral attention of
     a person in the vicinity of a display device of an
     apparatus by acquiring one or more sets of con-
     tent data from a content providing system and se-
     lectively displaying on the display device, in an
     unobtrusive manner that does not distract a
     user of the apparatus from a primary inter-
     action with the apparatus, an image or images
     generated from the set of content data. Accord-
     ing to a further aspect of the invention, the
     selective display of the image or images be-
     gins automatically after detection of an idle
     period of predetermined duration (the
     “screen saver embodiment”). This aspect can
     be implemented, for example, using the screen
     saver API (application program interface) that is
     part of many operating systems. According to
INTERVAL LICENSING LLC   v. AOL, INC.                    15



   another further aspect of the invention, the
   selective display of an image or images oc-
   curs while the user is engaged in a primary
   interaction with the apparatus, which pri-
   mary interaction can result in the display of
   an image or images in addition to the image
   or images generated from the set of content
   data (the “wallpaper embodiment”).
Id. at 3:11–31 (emphases added).
    The specification here suggests that possibly both the
screen saver and wallpaper embodiments are “further
aspects” of an attention manager that displays content “in
an unobtrusive manner that does not distract a user of
the apparatus from a primary interaction with the appa-
ratus.” Although Interval disputes this reading, we find
that the specification is at best muddled, leaving one
unsure of whether the “unobtrusive manner” phrase has
temporal dimensions as well as spatial dimensions. The
hazy relationship between the claims and the written
description fails to provide the clarity that the subjective
claim language needs. See Datamize, 417 F.3d at 1352
(holding claim term “aesthetically pleasing” indefinite
because, even though the preferred embodiment provided
“examples of aesthetic features of screen displays that can
be controlled by the authoring system,” the specification
did not indicate “what selection of these features would be
‘aesthetically pleasing’”); In re Hammack, 427 F.2d 1378,
1381–82 (C.C.P.A. 1970) (finding claims invalid for indef-
initeness where claims “serv[ed] as a shadowy framework
upon which are located words lacking in precise referents
in the specification” (internal quotations omitted)).
    The prosecution history further illustrates the diffi-
culty in pinning down the relationship between the writ-
ten description and the “in an unobtrusive manner that
does not distract the user” claim phrase. The statements
of Interval, and the responses of the USPTO, reflect
16                      INTERVAL LICENSING LLC   v. AOL, INC.



considerable uncertainty about which embodiments were
tied to the “unobtrusive manner” language. During
prosecution in 1998, Interval relied on a different reading
than the one it offers now, stating that “[t]he display of
images in an unobtrusive manner in a system as recited
in Claim 1 can be implemented by, for example, display-
ing images during an inactive period (e.g., when the user
has not interacted with the apparatus for a predeter-
mined period of time) of a primary interaction with the
apparatus (the ‘screensaver embodiment’).” J.A. 985.
Interval points out, however, that the examiner appeared
not to share Interval’s initial understanding: later in the
prosecution, the examiner discussed the “unobtrusive
manner” limitation in conjunction with the wallpaper
embodiment but not the screen saver embodiment. J.A.
1073.
    The USPTO expressed a similar understanding dur-
ing reexaminations of the ’652 and ’314 patents, with
examiners finding that the specification links the “unob-
trusive manner” language to the wallpaper embodiment,
excluding the screensaver embodiment. See J.A. 1090–91,
1311. But in a recent decision addressing the scope and
validity of the ’314 patent, the Patent Trial and Appeal
Board disagreed with the examiner. Apple, Inc. v. Inter-
val Licensing LLC, No. 2013-005424, 2014 WL 1322685
(Patent Tr. & App. Bd. Apr. 1, 2014). 7 The Board con-



     7  The Board’s decision was a response to an appeal
from an inter partes reexamination. Per 37 C.F.R.
§ 1.906, the Board was limited to the question of whether
the challenged claims should be rejected on the basis of
prior art patents or printed publications. Neither the
examiner nor the Board could address claim definiteness.
The claims were given “their broadest reasonable con-
struction” during reexamination. In re Am. Acad. Of Sci.
Tech Ctr., 367 F.3d 1359, 1364 (Fed. Cir. 2004).
INTERVAL LICENSING LLC   v. AOL, INC.                      17



cluded that, in light of “the ambiguous nature” of the
specification, “the claim term ‘unobtrusive manner’ in-
cludes the screensaver embodiment.” Id. at *7. 8
    After reviewing the specification and prosecution his-
tory, we find that the “unobtrusive manner” phrase has
too uncertain a relationship to the patents’ embodiments.
Contrary to Interval’s suggestion, the wallpaper embodi-
ment does not provide a reasonably clear and exclusive
definition, leaving the facially subjective claim language
without an objective boundary.
                               ii
    In the alternative, Interval suggests that if we are not
persuaded that the wallpaper embodiment defines the
“unobtrusive manner” phrase, then we must at least
adopt a “narrow example” from the specification. That
example lies in the Summary of the Invention, which
explains that information can be presented “in an unob-
trusive manner that does not distract the user from the
primary interaction with the apparatus (e.g., the infor-
mation is presented in areas of a display screen that are
not used by displayed information associated with the
primary interaction with the apparatus).” ’652 patent,
2:15–19 (emphasis added).
   We recognize that a patent which defines a claim
phrase through examples may satisfy the definiteness
requirement. See, e.g., Enzo Biochem, 599 F.3d at 1336


    8   At the hearing before the Board, counsel for In-
terval acknowledged the lack of clarity in column 3 of the
specification: “I would say in this summary location
within the specification [the drafters] were a little bit less
precise, a little bit sloppy here . . . it might seem less
precise or even possibly contradictory. . . . My point is
simply that at best it’s ambiguous.” Id. at *6 (internal
citations omitted).
18                       INTERVAL LICENSING LLC   v. AOL, INC.



(holding that “not interfering substantially” is sufficiently
definite because one of skill in the art could use “the
examples in the specification to determine whether inter-
ference with hybridization is substantial”). In this case,
however, we decline to cull out a single “e.g.” phrase from
a lengthy written description to serve as the exclusive
definition of a facially subjective claim term. See Nauti-
lus, 134 S. Ct. at 2130 (disfavoring “post hoc” efforts to
“ascribe some meaning to a patent’s claims”).

    Had the phrase been cast as a definition instead of as
an example—if the phrase had been preceded by “i.e.”
instead of “e.g.”—then it would help provide the clarity
that the specification lacks. But as the specification is
written, we agree with the district court that a person of
ordinary skill in the art would not understand the “e.g.”
phrase to constitute an exclusive definition of “unobtru-
sive manner that does not distract a user.” See Interval,
2013 WL 792791, at *4. With this lone example, a skilled
artisan is still left to wonder what other forms of display
are unobtrusive and non-distracting. What if a displayed
image takes up 20% of the screen space occupied by the
primary application with which the user is interacting? Is
the image unobtrusive? The specification offers no indica-
tion, thus leaving the skilled artisan to consult the “un-
predictable vagaries of any one person’s opinion.” See
Datamize, 417 F.3d at 1350. Such ambiguity falls within
“the innovation-discouraging ‘zone of uncertainty’ against
which [the Supreme Court] has warned.” Nautilus, 134
S. Ct. at 2130 (internal citation omitted).
    In sum, the “unobtrusive manner that does not dis-
tract a user” phrase, when viewed in light of the specifica-
tion and prosecution history, fails to “inform those skilled
in the art about the scope of the invention with reasona-
ble certainty.” See id. at 2129. The claims that depend on
that phrase are thus invalid for indefiniteness.
INTERVAL LICENSING LLC   v. AOL, INC.                   19



                 II. Claim Construction
    We review claim construction de novo. Lighting Bal-
last Control LLC v. Philips Elecs. N. Am. Corp., 744 F.3d
1272, 1276–77 (Fed. Cir. 2014) (en banc); Cybor Corp. v.
FAS Techs., Inc., 138 F.3d 1448, 1451 (Fed. Cir. 1998) (en
banc). The words of a claim “are generally given their
ordinary and customary meaning,” which 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.” Phillips
v. AWH Corp., 415 F.3d 1303, 1312–13 (Fed. Cir. 2005)
(en banc) (internal citations omitted). Claim language
must be viewed in light of the specification, which is “the
single best guide to the meaning of a disputed term.” Id.
at 1315 (quoting Vitronics Corp. v. Conceptronic, Inc., 90
F.3d 1576, 1582 (Fed. Cir. 1996)). In addition to consult-
ing the specification, we may also consider the prosecu-
tion history and any relevant extrinsic evidence. Id. at
1315–17.
        A. Construction of “Attention Manager”
    As discussed in the Background, supra, the phrase
“attention manager” appears in claims 15–18 of the ’652
patent. In its claim construction order, the district court
adopted the Defendants’ proposed construction: “a system
that displays images to a user either when the program
detects that the user is not engaged in a primary interac-
tion or as a background of the computer screen.” Interval,
2013 WL 792791, at *11. The court explained that it
relied on “the only description in the specification that
gives objective boundaries to the scope of this limitation:
the ‘screensaver’ and ‘wallpaper’ embodiments.” Id.
    In contrast to the “in an unobtrusive manner that
does not distract a user” phrase, there is no uncertainty
about the definitional relationship between the claim
term “attention manager” and the written description.
The patented invention is a self-coined “attention manag-
er.” No one disputes that the “attention manager” is
20                        INTERVAL LICENSING LLC   v. AOL, INC.



defined by all of the disclosed embodiments. What is in
dispute, and what we must consider in reviewing the
construction of “attention manager,” is whether the
district court read the embodiments too narrowly and
thus improperly limited the scope of the claim term.
     Interval proposes modifying the claim construction as
follows:
     a system that displays images to a user either
     when the program detects that the user is not en-
     gaged in a primary interaction or as a background
     of the computer screen an area of the display
     screen that is not substantially used by the
     user’s primary activity.
See Appellant’s Br. 53.
    With regard to the first proposed modification—the
removal of “the program detects that” phrase—Interval
argues that the district court mistakenly limited the
screen saver to a single mode of operation. Interval notes
that the specification describes two ways of activating the
screen saver: (1) through the detection of an idle period
or, alternatively, (2) through direct user activation. See
’652 patent, 9:21–36. In response, the Defendants suggest
that the system still “detects” user activation even in the
alternative embodiment, and that the district court’s
inclusion of “detects” is thus consistent with the patents’
description of the screen saver. Although the Defendants’
reading is plausible, we think that Interval’s reading
better conforms to the distinction drawn between “detec-
tion” and “user-activation” in the written description. We
therefore agree with Interval that the phrase “the pro-
gram detects that” should be removed from the construc-
tion.
    With regard to the second proposed modification—the
replacement of “a background of the computer screen”
with “as an area of the display screen that is not substan-
INTERVAL LICENSING LLC   v. AOL, INC.                    21



tially used by the user’s primary activity”—Interval
argues that its change is faithful to a “lexicographical
definition” in the specification of the ’652 patent. Appel-
lant’s Br. 53 (citing Phillips, 415 F.3d at 1321). Interval
faults the district court for basing its construction on a
general definition of “wallpaper” in the specification. See
’652 patent, 1:50–52 (describing wallpaper as “a pattern
generated in the background portions on a computer
display”). Instead, Interval urges, the construction should
be based on an express definition of “wallpaper embodi-
ment”:
    According to another further aspect of the inven-
    tion, the selective display of an image or images
    occurs while the user is engaged in a primary in-
    teraction with the apparatus, which primary in-
    teraction can result in the display of an image or
    images in addition to the image or images gener-
    ated from the set of content data (the “wallpaper
    embodiment”).
Id. at 3:25–31.
    We agree with Interval that the wallpaper embodi-
ment of the attention manager should not be strictly
limited to the “background” of a computer screen, and we
agree that the specification’s description of the embodi-
ment should inform our construction. The district court’s
construction suggests that displayed images must be
integrated into the background display, similar to the
“patterns” of the traditional wallpaper described in the
background of the invention. See id. at 1:50–52. But the
patents’ description of the wallpaper embodiment sup-
ports a broader reading. The patent describes the embod-
iment as making use of unused spatial capacity—that is,
space in the display not used by the user’s primary inter-
action. See id. at 3:25–31, 6:45–51. The specification does
not indicate that the images must be displayed as part of
the background of the display device.
22                        INTERVAL LICENSING LLC   v. AOL, INC.



    We note, however, that Interval’s proposed modifica-
tion (“an area of the display screen that is not substantial-
ly used by the user’s primary activity”) is not taken
directly from the cited “lexicography.” Rather, the pro-
posed language appears to be Interval’s interpretation of
where the images will be displayed while the user is
engaged in a primary interaction. Based on our reading
of the specification, the attention manager is better
construed as displaying images in areas “not used”—
instead of “not substantially used”—by the user’s primary
activity. The specification consistently describes how the
attention manager makes use of “unused capacity.”
Moreover, the specification twice contrasts a user’s “pri-
mary interaction with the apparatus” with the display of
information in areas “not used” by the information associ-
ated with the primary interaction. See id. at 2:15–19,
6:43–45. The phrase “not substantially used,” by contrast,
appears nowhere in the specification.
    In sum, with the exception of the addition of the word
“substantially,” we agree with Interval’s proposed con-
struction of “attention manager.” Accordingly, we adopt
the following construction: “a system that displays imag-
es to a user either when the user is not engaged in a
primary interaction or in an area of the display screen
that is not used by the user’s primary activity.”
             B. Construction of “Instructions”
    The district court construed “instructions” as “a
statement in a programming language that specifies a
function to be performed by a system.” Interval, 2013 WL
792791, at *15–16. Although the district court’s construc-
tion of “instructions” was not dispositive with respect to
the final judgment of invalidity and non-infringement,
Interval asks us to review that construction now. Specifi-
cally, Interval asks us to clarify that “instructions,” in the
context of the patents, “may encompass ‘data’” and “need
INTERVAL LICENSING LLC   v. AOL, INC.                      23



not be written ‘in a programming language.’” Appellant’s
Br. 61–62.
    In the interest of judicial economy, we have the dis-
cretion to review a non-dispositive claim construction if
we believe that the construction may become important
on remand. See Deere & Co. v. Bush Hog, LLC, 703 F.3d
1349, 1357 (Fed. Cir. 2012); Advanced Software Design
Corp. v. Fiserv, Inc., 641 F.3d 1368, 1378 (Fed. Cir. 2011).
Because we are vacating the judgment of non-
infringement as to claims 15–18 of the ’652 patent, and
because those claims include the term “instructions,” we
take this opportunity to address the claim construction of
that term.
    During claim construction, Interval argued that “in-
structions” should be construed to cover “data related to
the accomplishment of a function.” J.A. 27. Relying
principally on the distinction between “instructions” and
“data” in the specification, the district court refused to
adopt Interval’s construction. See Interval, 2013 WL
792791, at *15–16. We share the district court’s reading.
     Interval notes that the specification refers to certain
“instructions” as “functional components,” ’652 patent,
14:49–53, which may be represented by “data.” Id. at
14:53–57 (“Each of the functional components are repre-
sented by a set of instructions and/or data. In particular,
each of the instructions may include, if appropriate, data
related to accomplishment of the functions associated
with the set of instructions . . . .”). Although Interval
reads the cited portion of the specification as showing that
data alone can constitute an “instruction,” we read the
specification as maintaining a distinction between “in-
structions” and “data.” An instruction “may . . . include
data,” not consist of data; the instruction is not the data
itself. As the district court observed, “[i]f ‘data’ is a type
of ‘instructions,’ then the phrase ‘instructions and/or data’
would not make sense.” Interval, 2013 WL 792791, at
24                      INTERVAL LICENSING LLC   v. AOL, INC.



*16. Moreover, the district court’s reading is consistent
with extrinsic evidence suggesting that the distinction
between “instructions” and “data” is widely recognized in
the field of art. See J.A. 845 (“The distinction between
program (instructions) and data is a fundamental one in
computing.” (quoting Oxford Dictionary of Computing)).
For these reasons, we decline Interval’s invitation to call
into question the distinction between “instructions” and
“data” in the district court’s construction.
    As for Interval’s concerns regarding the “in a pro-
gramming language” phrase, we find that a modification
to the construction is necessary. Although the district
court carefully explained why the intrinsic evidence
supported the exclusion of the word “data” from its con-
struction, the court offered no direct explanation for its
inclusion of the “in a programming language” limitation.
The patents’ specification does not indicate that instruc-
tions must take the form of programming language
statements. The source of that limitation is the IEEE
Standard Dictionary of Electrical and Electronics Terms
(6th ed. 1996) (“IEEE Dictionary”), which the Defendants
relied on for their proposed construction. See J.A. 419,
484.
    The IEEE Dictionary includes five different defini-
tions of “computer instruction,” with two definitions
specifically directed towards “software” computer instruc-
tions. The Defendants based their construction on one of
those two definitions: “A statement in a programming
language, specifying an operation to be performed by a
computer and the addresses or values of the associated
operands; for example, Move A to B.” Id. at 484. The
second definition, which the Defendants did not reference,
reads: “Loosely, any executable statement in a computer
program.” Id.
    We have recognized that technical dictionaries “can
assist the court in determining the meaning of particular
INTERVAL LICENSING LLC   v. AOL, INC.                    25



terminology to those of skill in the art of the invention.”
Phillips, 415 F.3d at 1318. At the same time, we have
cautioned against relying on dictionary definitions at the
expense of a fair reading of the claims, which must be
understood in light of the specification. See id. at 1321–
22. Here, considering that the patents’ specification does
not use “instructions” in relation to “programming lan-
guage statements,” we find that the broader dictionary
definition (“any executable statement in a computer
program”) is preferable.
    Moreover, we share Interval’s concern that the “in a
programming language” limitation will breed unnecessary
uncertainty about whether “instructions” may take the
form of object code. As Interval notes, one could argue
that object code—which may consist of strings of 1’s and
0’s—is not a “programming language.” The IEEE Dic-
tionary, however, defines “object code” as “[c]omputer
instructions and data definitions in a form output by an
assembler or a compiler.”
    In sum, the extrinsic source on which the district
court relied suggests a broader construction of “instruc-
tions” than the court adopted. We conclude that a con-
struction without the “in a programming language”
phrase is both simpler and more accurate. Accordingly,
we adopt the following construction: “a statement that
specifies a function to be performed by a system.”
                         CONCLUSION
    We hold that the claim phrase “in an unobtrusive
manner that does not distract a user” is indefinite under
35 U.S.C. § 112, ¶ 2. Therefore, the district court correct-
ly granted judgments of invalidity as to claims 4–8, 11,
34, and 35 of the ’652 patent and claims 1–4 and 7–15 of
the ’314 patent. However, the district court erred in
granting judgments of non-infringement as to claims 15–
18 of the ’652 patent based on the erroneous claim con-
struction of “attention manager.” We therefore affirm the
26                        INTERVAL LICENSING LLC   v. AOL, INC.



judgments of invalidity, vacate the judgments of non-
infringement, and remand to the district court for further
proceedings consistent with this opinion.
 AFFIRMED–IN–PART, VACATED–IN–PART, AND
               REMANDED
                           COSTS
     Each party shall bear its own costs.
