Source: s3://data.kl3m.ai/documents/govinfo/USCOURTS/USCOURTS-ca13-13-01130/USCOURTS-ca13-13-01130-1/pdf.json

Nature of Suit Code: 830
Nature of Suit: Patent
Cause of Action: 

---

United States Court of Appeals 

for the Federal Circuit ______________________ 

RICHARD A. WILLIAMSON, Trustee for At Home 

Bondholders Liquidating Trust,

Plaintiff-Appellant

v.

CITRIX ONLINE, LLC, CITRIX SYSTEMS, INC., 

MICROSOFT CORPORATION,

ADOBE SYSTEMS, INC.,

Defendants-Appellees

WEBEX COMMUNICATIONS, INC., CISCO WEBEX,

LLC, CISCO SYSTEMS, INC.,

Defendants-Appellees

INTERNATIONAL BUSINESS MACHINES 

CORPORATION,

Defendant-Appellee

______________________ 

2013-1130

______________________ 

Appeal from the United States District Court for the 

Central District of California in No. 11-CV-2409, Judge A. 

Howard Matz.

______________________ 

Decided: June 16, 2015

______________________ 

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2 WILLIAMSON v. CITRIX ONLINE, LLC

BRETT JOHNSTON WILLIAMSON, O’Melveny & Myers 

LLP, Newport Beach, CA, argued for plaintiff-appellant. 

Also represented by TIM D. BYRON; WILLIAM C. NORVELL,

JR., SCOTT DION MARRS, BRIAN T. BAGLEY, Beirne 

Maynard & Parsons, LLP, Houston, TX. 

KURT LOUIS GLITZENSTEIN, Fish & Richardson P.C., 

Boston, MA, argued for all defendants-appellees. Citrix 

Online, LLC, Citrix Systems, Inc., Microsoft Corporation, 

Adobe Systems, Inc., also represented by FRANK 

SCHERKENBACH; INDRANIL MUKERJI, Washington, DC; 

JONATHAN J. LAMBERSON, Redwood City, CA. Defendantappellee Microsoft Corporation also represented by

ISABELLA FU, Microsoft Corporation, Redmond, WA. 

DOUGLAS M. KUBEHL, Baker Botts LLP, Dallas, TX, 

for defendants-appellees Webex Communications, Inc.,

Cisco Webex, LLC, Cisco Systems, Inc. Also represented 

by SAMARA KLINE, BRIAN DOUGLAS JOHNSTON. 

MARK J. ABATE, Goodwin Procter LLP, New York, NY, 

for defendant-appellee International Business Machines 

Corporation. Also represented by CALVIN E. WINGFIELD,

JR.; WILLIAM F. SHEEHAN, Washington, DC. 

______________________ 

Before MOORE, LINN, and REYNA, Circuit Judges.1

Opinion for the court filed by Circuit Judge LINN. 

Opinion concurring in part, dissenting in part, and with 

additional views filed by Circuit Judge REYNA. 

1 The earlier opinion in this case, reported at 770 

F.3d 1371 (Fed. Cir. 2014), is withdrawn, and this opinion 

substituted therefore. Part II.C.1. of this opinion has 

been considered and decided by the court en banc. See

Order in this case issued this date.

 

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WILLIAMSON v. CITRIX ONLINE, LLC 3

PROST, Chief Judge, LOURIE, LINN, DYK, MOORE,

O’MALLEY,REYNA,WALLACH, TARANTO,CHEN, and

HUGHES, Circuit Judges, have joined Part II.C.1. of this 

opinion.

Opinion dissenting from Part II.C.1. filed by Circuit 

Judge NEWMAN. 

LINN, Circuit Judge. 

Richard A. Williamson (“Williamson”), as trustee for 

the At Home Corporation Bondholders’ Liquidating Trust, 

owns U.S. Patent No. 6,155,840 (the “’840 patent”) and 

appeals from the stipulated final judgment in favor of 

defendants Citrix Online, LLC; Citrix Systems, Inc.; 

Microsoft Corporation; Adobe Systems, Inc.; Webex Communications, Inc.; Cisco Webex, LLC; Cisco Systems, Inc.; 

and International Business Machines Corporation (collectively, “Appellees”). Because the district court erroneously construed the limitations “graphical display 

representative of a classroom” and “first graphical display 

comprising . . . a classroom region,” we vacate the judgment of non-infringement of claims 1–7 and 17–24 of 

the ’840 patent. Because the district court correctly 

construed the limitation “distributed learning control 

module,” we affirm the judgment of invalidity of claims 8–

12 of the ’840 patent under 35 U.S.C. § 1122, para. 2. 

Accordingly, we remand.

2 35 U.S.C. § 112 was amended and subsections 

were renamed by the America Invents Act, Pub. L. No. 

112-29 (“AIA”), which took effect on September 16, 2012. 

Because the application resulting in the ’840 patent was 

filed before that date, this opinion refers to the pre-AIA 

version of § 112.

 

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4 WILLIAMSON v. CITRIX ONLINE, LLC

I. BACKGROUND

A. The ’840 Patent

The ’840 patent describes methods and systems for 

“distributed learning” that utilize industry standard 

computer hardware and software linked by a network to 

provide a classroom or auditorium-like metaphor—i.e., a 

“virtual classroom” environment. The objective is to 

connect one or more presenters with geographically 

remote audience members. ’840 patent col.2 ll.10–14. 

The disclosed inventions purport to provide “the benefits 

of classroom interaction without the detrimental effects of 

complicated hardware or software, or the costs and inconvenience of convening in a separate place.” Id. at col.2 

ll.4–7.

There are three main components of the “distributed 

learning” system set forth in the ’840 patent: (1) a presenter computer, (2) audience member computers, and (3) 

a distributed learning server. The distributed learning 

server implements a “virtual classroom” over a computer 

network, such as the Internet, to facilitate communication 

and interaction among the presenter and audience members. The presenter computer is used by the presenter to 

communicate with the audience members and control 

information that appears on the audience member’s 

computer screen. Id. at col.4 l.66–col.5 l.2. An audience 

member’s computer is used to display the presentation 

and can be used to communicate with the presenter and 

other audience members. Id. at col.5 ll.11–14.

The ’840 patent includes the following three independent claims, with disputed terms highlighted:

1. A method of conducting distributed learning 

among a plurality of computer systems coupled to 

a network, the method comprising the steps of:

providing instructions to a first computer system coupled to the network for:

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WILLIAMSON v. CITRIX ONLINE, LLC 5

creating a graphical display representative 

of a classroom; 

creating a graphical display illustrating 

controls for selecting first and second data 

streams;

creating a first window for displaying the 

first selected data stream; and

creating a second window for displaying 

the second selected data stream, wherein

the first and second windows are displayed simultaneously; and

providing instructions to a second computer 

system coupled to the network for:

creating a graphical display representative 

of the classroom; 

creating a third window for displaying the 

first selected data stream; and

creating a fourth window for displaying 

the second selected data stream, wherein

the third and fourth windows are displayed simultaneously.

8. A system for conducting distributed learning 

among a plurality of computer systems coupled to 

a network, the system comprising:

a presenter computer system of the plurality 

of computer systems coupled to the network and 

comprising:

a content selection control for defining at 

least one remote streaming data source and 

for selecting one of the remote streaming data 

sources for viewing; and

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6 WILLIAMSON v. CITRIX ONLINE, LLC

a presenter streaming data viewer for displaying data produced by the selected remote 

streaming data source;

an audience member computer system of the 

plurality of computer systems and coupled to the 

presenter computer system via the network, the 

audience member computer system comprising:

an audience member streaming data 

viewer for displaying the data produced by the 

selected remote streaming data source; and

a distributed learning server remote from the 

presenter and audience member computer systems of the plurality of computer systems and 

coupled to the presenter computer system and the 

audience member computer system via the network and comprising:

a streaming data module for providing the 

streaming data from the remote streaming data source selected with the content selection 

control to the presenter and audience member 

computer systems; and

a distributed learning control module for 

receiving communications transmitted between the presenter and the audience member 

computer systems and for relaying the communications to an intended receiving computer system and for coordinating the operation 

of the streaming data module.

17. A distributed learning server for controlling a 

presenter computer system and an audience 

member computer system coupled to the distributed learning server via a network, the distributed learning server comprising:

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WILLIAMSON v. CITRIX ONLINE, LLC 7

a module for providing a first graphical display on the presenter computer system, the first 

graphical display comprising: 

a first presenter content selection control 

for selecting a first source of streaming content representative of graphical information;

a first presenter content display region for 

displaying the graphical information represented by the streaming content from the first 

selected source;

a second presenter content selection control for selecting a second source of streaming 

content representative of graphical information; and

a second presenter content display region 

for displaying the graphical information represented by the streaming content from the 

second selected source, wherein the first and 

second presenter content display regions are 

adapted to display simultaneously; and

a classroom region for representing the 

audience member computer system coupled to 

the distributed learning server; and

a module for providing a second graphical display on the audience member computer system, 

the second graphical display comprising:

a first audience member content display 

region for displaying the graphical information represented by the streaming content 

from the first source selected by the content 

selection control; and

a second audience member content display 

region for displaying the graphical information represented by the streaming content 

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8 WILLIAMSON v. CITRIX ONLINE, LLC

from the second source selected by the content 

selection control, wherein the first and second 

audience member content display regions are 

adapted to display simultaneously.

Id. at col.10 ll.28–52, col.11 ll.26–62, col.12 ll.29–65. 

B. Procedural History

Williamson accused Appellees of infringing the ’840

patent based on their alleged manufacture, sale, offer for 

sale, use, and importation of various systems and methods of online collaboration. On March 22, 2011, Williamson filed suit in the United States District Court for the 

Central District of California specifically asserting infringement of all 24 claims of the ’840 patent. On September 4, 2012, the district court issued a claim 

construction order, construing, inter alia, the following 

limitations of independent claims 1 and 17: “graphical 

display representative of a classroom” and “first graphical 

display comprising . . . a classroom region” (collectively,

the “graphical display” limitations). The district court 

held that these terms require “a pictorial map illustrating 

an at least partially virtual space in which participants 

can interact, and that identifies the presenter(s) and the 

audience member(s) by their locations on the map.”

In its claim construction order, the district court also 

concluded that the limitation of claim 8, “distributed 

learning control module,” was a means-plus-function term 

under 35 U.S.C. § 112, para. 6. The district court then 

evaluated the specification and concluded that it failed to 

disclose the necessary algorithms for performing all of the 

claimed functions. The district court thus held claim 8

and its dependent claims 9–16 invalid as indefinite under 

§ 112, para. 2.

Williamson conceded that under the district court’s 

claim constructions, none of Appellees’ accused products 

infringed independent claims 1 and 17 and their respecCase: 13-1130 Document: 99-2 Page: 8 Filed: 06/16/2015
WILLIAMSON v. CITRIX ONLINE, LLC 9

tive dependent claims 2–7 and 18–24, and that claims 8–

16 were invalid. The parties stipulated to final judgment. 

Williamson appeals the stipulated entry of judgment, 

challenging these claim construction rulings. We have 

jurisdiction pursuant to 28 U.S.C. § 1295(a)(1). 

II. DISCUSSION

A. Standard of Review

Regarding questions of claim construction, including 

whether claim language invokes 35 U.S.C. § 112, para. 6, 

the district court’s determinations based on evidence 

intrinsic to the patent as well as its ultimate interpretations of the patent claims are legal questions that we 

review de novo. Teva Pharm. USA, Inc. v. Sandoz, Inc., 

135 S. Ct. 831, 840-41 (2015). To the extent the district 

court, in construing the claims, makes underlying findings of fact based on extrinsic evidence, we review such 

findings of fact for clear error. Id. Because the district 

court’s claim constructions in this case were based solely 

on the intrinsic record, the Supreme Court’s recent decision in Teva does not require us to review the district 

court’s claim construction any differently than under the 

de novo standard we have long applied. Fenner Invs., Ltd. 

v. Cellco P’ship, 778 F.3d 1320, 1322 (Fed. Cir. 2015) 

(“When the district court reviews only evidence intrinsic 

to the patent . . . , the judge’s determination will amount 

solely to a determination of law, and [we] review that 

construction de novo.” (quoting Teva, 135 S. Ct. at 841)) 

(internal citations removed).

B. The “graphical display” Limitations

Williamson asserts that the district court erred in its 

construction of the graphical display terms by improperly 

importing an extraneous “pictorial map” limitation into 

the claim. Williamson argues that requiring a “map” 

unduly narrows the claims to the preferred embodiment 

disclosed in the written description and that there is no 

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10 WILLIAMSON v. CITRIX ONLINE, LLC

support in the intrinsic record for confining the claims to 

a “pictorial map” that identifies the location of the participants. Williamson alleges that a proper definition must 

require the audience members to be able to interact with 

both the presenter and other audience members. He 

therefore asserts that the proper construction of the 

graphical display terms is “a viewable illustration of an at 

least partially virtual space that allows audience members to interact with both the presenter and other audience members.”

Appellees respond that the district court’s construction correctly limited the claims to a “pictorial map” 

consistent with the teachings of the written description. 

According to Appellees, this construction does not import 

a limitation from the preferred embodiment, but simply 

reflects the functional aspects of a “classroom” in a manner that is consistent with what the patentee invented 

and disclosed. Moreover, according to Appellees, it is 

consistent with the only depiction of a classroom shown in 

the ’840 patent, which shows a pictorial map as a seating 

chart that identifies the presenters and audience members by their locations on the map.

We agree with Williamson. The district court erred in 

construing these terms as requiring a “pictorial map.” 

First, the claim language itself contains no such “pictorial 

map” limitation. “[I]t is the claims, not the written description, which define the scope of the patent right.” 

Laitram Corp. v. NEC Corp., 163 F.3d 1342, 1347 (Fed.

Cir. 1998); see also id. (“[A] court may not import limitations from the written description into the claims.”). 

While the specification discloses examples and embodiments where the virtual classroom is depicted as a “map” 

or “seating chart,” nowhere does the specification limit the 

graphical display to those examples and embodiments. 

This court has repeatedly “cautioned against limiting the 

claimed invention to preferred embodiments or specific 

examples in the specification.” Teleflex, Inc. v. Ficosa N. 

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WILLIAMSON v. CITRIX ONLINE, LLC 11

Am. Corp., 299 F.3d 1313, 1328 (Fed. Cir. 2002) (quoting 

cases) (citations omitted). 

Here, there is no suggestion in the intrinsic record 

that the applicant intended the claims to have the limited 

scope determined by the district court. To the contrary, 

the embodiments and examples in the specification of 

classroom metaphors relating to “maps” are consistently 

described in terms of preference. For example, the specification states that “[t]he classroom metaphor preferably

provides a map of the classroom showing the relative 

relationships among the presenters and audience members.” ’840 patent col.2 ll.37–39 (emphasis added). In 

another example, the graphical display of Figure 6 is 

described as an “exemplary display” on the presenter’s 

computer. Id. at col.7 ll.35–36. That exemplary display 

includes a window that “preferably provides a seating 

chart showing the audience members and presenters in 

the classroom or auditorium.” Id. at col.9 ll.5–7 (emphasis added). 

The ’840 patent defines a classroom as “an at least 

partially virtual space in which participants can interact.” 

Id. at col.6 ll.5–6. Nothing further is required, and no 

greater definition is mandated by the language of the 

claims, the specification, or the prosecution history. As is 

well settled, the claims must “not be read restrictively 

unless the patentee has demonstrated a clear intention to 

limit the claim scope using words or expressions of manifest exclusion or restriction.” Innova/Pure Water, Inc., v. 

Safari Water Filtration Sys., Inc., 381 F.3d 1111, 1117 

(Fed. Cir. 2004) (internal quotations omitted).

For the foregoing reasons, we conclude that the district court incorrectly construed the graphical display 

terms to have a “pictorial map” limitation. We therefore 

vacate the stipulated judgment of non-infringement of 

claims 1–7 and 17–24. The “graphical display” limitations 

in claims 1 and 17 are properly construed as “a graphical 

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12 WILLIAMSON v. CITRIX ONLINE, LLC

representation of an at least partially virtual space in 

which participants can interact.” 

C. The “distributed learning control module” 

Limitation

1. Applicability of 35 U.S.C. § 112, para. 63

Means-plus-function claiming occurs when a claim 

term is drafted in a manner that invokes 35 U.S.C. § 112, 

para. 6, which states:

An element in a claim for a combination may be 

expressed as a means or step for performing a 

specified function without the recital of structure, 

material, or acts in support thereof, and such 

claim shall be construed to cover the corresponding structure, material, or acts described in the 

specification and equivalents thereof.

In enacting this provision, Congress struck a balance in 

allowing patentees to express a claim limitation by reciting a function to be performed rather than by reciting 

structure for performing that function, while placing 

specific constraints on how such a limitation is to be 

construed, namely, by restricting the scope of coverage to 

only the structure, materials, or acts described in the 

specification as corresponding to the claimed function and 

equivalents thereof. See Northrop Grumman Corp. v. 

Intel Corp., 325 F.3d 1346, 1350 (Fed. Cir. 2003). 

3 Because the overruling of prior precedent can only 

be done by the court en banc, see South Corp. v. United 

States, 690 F.2d 1368, 1370 n. 2 (Fed. Cir. 1982) (en banc), 

Part II.C.1. of this opinion has been considered by an en 

banc court formed of PROST, Chief Judge, NEWMAN,

LOURIE, LINN, DYK, MOORE, O’MALLEY, REYNA, WALLACH,

TARANTO,CHEN, and HUGHES, Circuit Judges. 

 

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WILLIAMSON v. CITRIX ONLINE, LLC 13

To determine whether § 112, para. 6 applies to a claim 

limitation, our precedent has long recognized the importance of the presence or absence of the word “means.” 

In Personalized Media Communications, LLC v. International Trade Commission, building upon a line of cases 

interpreting § 112, para. 6,4 we stated that the use of the 

word “means” in a claim element creates a rebuttable 

presumption that § 112, para. 6 applies. 161 F.3d 696, 

703–04 (Fed. Cir. 1998) (citing cases). Applying the 

converse, we stated that the failure to use the word 

“means” also creates a rebuttable presumption—this time 

that § 112, para. 6 does not apply. Id. We have not, 

however, blindly elevated form over substance when 

evaluating whether a claim limitation invokes § 112, 

para. 6:

Merely because a named element of a patent 

claim is followed by the word “means,” however, 

does not automatically make that element a 

“means-plus-function” element under 35 U.S.C. 

§ 112, ¶ 6. . . . The converse is also true; merely 

because an element does not include the word 

“means” does not automatically prevent that element from being construed as a means-plusfunction element.

Cole v. Kimberly-Clark Corp., 102 F.3d 524, 531 (Fed. Cir. 

1996); see also Greenberg v. Ethicon Endo-Surgery, Inc., 

91 F.3d 1580, 1584 (Fed. Cir. 1996) (“We do not mean to 

4 See, e.g., Laitram Corp. v. Rexnord, Inc., 939 F.2d 

1533 (Fed. Cir. 1991); Greenberg v. Ethicon Endo-Surgery, 

Inc., 91 F.3d 1580 (Fed. Cir. 1996); Cole v. Kimberly-Clark 

Corp., 102 F.3d 524 (Fed. Cir. 1997); Mas-Hamilton 

Group v. LaGard, Inc., 156 F.3d 1206 (Fed. Cir. 1998); 

Unidynamics Corp. v. Automatic Prods. Int’l, Ltd., 157 

F.3d 1311 (Fed. Cir. 1998).

 

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14 WILLIAMSON v. CITRIX ONLINE, LLC

suggest that section 112(6) is triggered only if the claim 

uses the word ‘means.’”).

In making the assessment of whether the limitation 

in question is a means-plus-function term subject to the 

strictures of § 112, para. 6, our cases have emphasized 

that the essential inquiry is not merely the presence or 

absence of the word “means” but whether the words of the 

claim are understood by persons of ordinary skill in the 

art to have a sufficiently definite meaning as the name for 

structure. Greenberg, 91 F.3d at 1583 (“What is important is . . . that the term, as the name for structure, 

has a reasonably well understood meaning in the art.”). 

When the claim uses the word “means,” our cases have 

been consistent in looking to the meaning of the language 

of the limitation in assessing whether the presumption is 

overcome. We have also traditionally held that when a 

claim term lacks the word “means,” the presumption can 

be overcome and § 112, para. 6 will apply if the challenger 

demonstrates that the claim term fails to “recite[] sufficiently definite structure” or else recites “function without 

reciting sufficient structure for performing that function.” 

Watts v. XL Sys., Inc., 232 F.3d 877, 880 (Fed. Cir. 2000).

In Lighting World, Inc. v. Birchwood Lighting, Inc., 

382 F.3d 1354, 1358 (Fed. Cir. 2004), we applied for the 

first time a different standard to the presumption flowing 

from the absence of the word “means” and held that “the 

presumption flowing from the absence of the term ‘means’ 

is a strong one that is not readily overcome” (emphasis 

added), citing as examples, Al–Site Corp. v. VSI International, Inc., 174 F.3d 1308, 1318–19 (Fed. Cir. 1999) and 

Personalized Media Communications, 161 F.3d at 703–05. 

A few years later, we reiterated Lighting World’s characterization of the presumption as a “strong one that is not 

readily overcome” in Inventio AG v. ThyssenKrupp Elevator Americas Corp., 649 F.3d 1350, 1358 (Fed. Cir. 2011). 

In Flo Healthcare Solutions, LLC v. Kappos, 697 F.3d 

1367, 1374 (Fed. Cir. 2012), decided just a year after 

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WILLIAMSON v. CITRIX ONLINE, LLC 15

Inventio, we raised the bar even further, declaring that 

“[w]hen the claim drafter has not signaled his intent to 

invoke § 112, ¶ 6 by using the term ‘means,’ we are unwilling to apply that provision without a showing that the 

limitation essentially is devoid of anything that can be 

construed as structure” (emphasis added), citing Masco 

Corp. v. United States, 303 F.3d 1316, 1327 (Fed. Cir.

2002), a case involving the different term “step for” and 

the unusual circumstances in which § 112, para. 6 relates 

to the functional language of a method claim. Recently, in 

Apple Inc. v. Motorola, Inc., 757 F.3d 1286, 1297 (Fed. Cir. 

2014), we yet again observed that this presumption is

“‘strong’ and ‘not readily overcome’” and noted that, as 

such, we have “‘seldom’ held that a limitation without 

recitation of ‘means’ is a means-plus-function limitation,”

citing Lighting World, 382 F.3d at 1358, 1362, Inventio,

649 F.3d at 1356, and Flo Healthcare, 697 F.3d at 1374. 

Our opinions in Lighting World, Inventio, Flo Healthcare

and Apple have thus established a heightened bar to 

overcoming the presumption that a limitation expressed 

in functional language without using the word “means” is 

not subject to § 112, para. 6.

Our consideration of this case has led us to conclude 

that such a heightened burden is unjustified and that we 

should abandon characterizing as “strong” the presumption that a limitation lacking the word “means” is not 

subject to § 112, para. 6. That characterization is unwarranted, is uncertain in meaning and application, and has 

the inappropriate practical effect of placing a thumb on 

what should otherwise be a balanced analytical scale. It 

has shifted the balance struck by Congress in passing 

§ 112, para. 6 and has resulted in a proliferation of functional claiming untethered to § 112, para. 6 and free of 

the strictures set forth in the statute. Henceforth, we will 

apply the presumption as we have done prior to Lighting 

World, without requiring any heightened evidentiary 

showing and expressly overrule the characterization of 

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16 WILLIAMSON v. CITRIX ONLINE, LLC

that presumption as “strong.” We also overrule the strict 

requirement of “a showing that the limitation essentially 

is devoid of anything that can be construed as structure.” 

The standard is whether the words of the claim are 

understood by persons of ordinary skill in the art to have 

a sufficiently definite meaning as the name for structure. 

Greenberg, 91 F.3d at 1583. When a claim term lacks the 

word “means,” the presumption can be overcome and 

§ 112, para. 6 will apply if the challenger demonstrates 

that the claim term fails to “recite sufficiently definite 

structure” or else recites “function without reciting sufficient structure for performing that function.” Watts, 232 

F.3d at 880. The converse presumption remains unaffected: “use of the word ‘means’ creates a presumption that 

§ 112, ¶ 6 applies.” Personalized Media, 161 F.3d at 703.

2. Functional Nature of the Limitation

On appeal, Williamson argues that the district court 

erred in construing the term “distributed learning control 

module” as being governed by 35 U.S.C. § 112, para. 6. 

Williamson contends that the district court failed to give 

appropriate weight to the “strong” presumption against 

means-plus-function claiming that attaches to claim 

terms that do not recite the word “means.” Williamson 

also argues that the district court wrongly focused its 

analysis on the word “module” instead of the full term, 

ignored the detailed support provided in the written 

description, and misapplied our law by failing to view the 

term from the perspective of one of ordinary skill in the 

art. 

Appellees respond that the district court properly construed “distributed learning control module” as a meansplus-function claim term despite the absence of the word 

“means.” Appellees assert that the presumption against 

means-plus-function claiming was rebutted because 

“distributed learning control module” does not have a well 

understood structural meaning in the computer technoloCase: 13-1130 Document: 99-2 Page: 16 Filed: 06/16/2015
WILLIAMSON v. CITRIX ONLINE, LLC 17

gy field. Appellees note that the “distributed learning 

control module” limitation is drafted in the same format 

as a traditional means-plus-function limitation, and 

merely replaces the term “means” with “nonce” word 

“module,” thereby connoting a generic “black box” for 

performing the recited computer-implemented functions. 

In Appellees’ view, since the term should be treated as a 

means-plus-function claim term and there is no algorithmic structure for implementing the claimed functions in 

the written description, the finding of indefiniteness 

should be affirmed. 

We begin with the observation that the claim limitation in question is not merely the introductory phrase 

“distributed learning control module,” but the entire 

passage “distributed learning control module for receiving 

communications transmitted between the presenter and 

the audience member computer systems and for relaying 

the communications to an intended receiving computer 

system and for coordinating the operation of the streaming data module.” This passage, as lengthy as it is, is 

nonetheless in a format consistent with traditional 

means-plus-function claim limitations. It replaces the 

term “means” with the term “module” and recites three 

functions performed by the “distributed learning control 

module.” 

“Module” is a well-known nonce word that can operate 

as a substitute for “means” in the context of § 112, para. 6. 

As the district court found, “‘module’ is simply a generic 

description for software or hardware that performs a 

specified function.” J.A. 31. Generic terms such as 

“mechanism,” “element,” “device,” and other nonce words 

that reflect nothing more than verbal constructs may be 

used in a claim in a manner that is tantamount to using 

the word “means” because they “typically do not connote 

sufficiently definite structure” and therefore may invoke 

§ 112, para. 6. Mass. Inst. of Tech. & Elecs. for Imaging, 

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18 WILLIAMSON v. CITRIX ONLINE, LLC

Inc. v. Abacus Software, 462 F.3d 1344, 1354 (Fed. Cir. 

2006); see generally M.P.E.P. § 2181.

Here, the word “module” does not provide any indication of structure because it sets forth the same black box 

recitation of structure for providing the same specified 

function as if the term “means” had been used.5 Indeed, 

Williamson himself acknowledges that “the term ‘module,’ 

standing alone is capable of operating as a ‘nonce word’ 

substitute for ‘means.’” Op. Br. at 43. 

The prefix “distributed learning control” does not impart structure into the term “module.” These words do 

not describe a sufficiently definite structure. Although 

the “distributed learning control module” is described in a 

certain level of detail in the written description, the 

written description fails to impart any structural significance to the term. At bottom, we find nothing in the 

specification or prosecution history that might lead us to 

5 We have addressed the use of the word “module” 

in a means-plus-function dispute in the unpublished 

decision Ranpak Corp. v. Storopack, Inc., 168 F.3d 1316, 

No. 98-1009, 1998 WL 513598 (Fed. Cir. July 15, 1998) 

(unpublished). In Ranpak, we were presented with two 

closely related claim terms, a “settable control means,” 

which indisputably invoked means-plus-function claiming, and a “settable control module.” Id. at *2. In the 

context of the patent at issue, we found that the word 

“module” in the term “settable control module” did not 

connote structure. Id. We came to this conclusion because “module” merely sets forth “the same black box 

without recitation of structure for providing the same 

specified function” as did “means.” Id. Since there was no 

difference in the structural implications of the terms, we 

held that the presumption against means-plus-function 

claiming was rebutted and the “settable control module” 

was properly construed as a means-plus-function term.

 

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WILLIAMSON v. CITRIX ONLINE, LLC 19

construe that expression as the name of a sufficiently 

definite structure as to take the overall claim limitation 

out of the ambit of § 112, para. 6. While Williamson is 

correct that the presence of modifiers can change the 

meaning of “module,” the presence of these particular 

terms does not provide any structural significance to the 

term “module” in this case.

While portions of the claim do describe certain inputs 

and outputs at a very high level (e.g., communications 

between the presenter and audience member computer 

systems), the claim does not describe how the “distributed 

learning control module” interacts with other components 

in the distributed learning control server in a way that 

might inform the structural character of the limitation-inquestion or otherwise impart structure to the “distributed 

learning control module” as recited in the claim. 

Williamson also points to the declaration of Dr. Shukri Souri to show that one of ordinary skill in the art would 

understand the term “distributed learning control module” to connote structure. The district court did not 

discuss Dr. Souri’s testimony in its claim construction 

ruling. We have considered it but do not find it persuasive. Dr. Souri’s declaration, like the claim language and 

portions of the written description Williamson identifies, 

fails to describe how the distributed learning control 

module, by its interaction with the other components in 

the distributed learning control server, is understood as 

the name for structure. Dr. Souri also testified that, “as 

one of ordinary skill in the art, reading the specification, I 

would know exactly how to program” a computer to perform the recited functions and further testified that 

structure “could be in software or it could be in hardware.” J.A. 1391 (256:12–258:16). But the fact that one 

of skill in the art could program a computer to perform 

the recited functions cannot create structure where none 

otherwise is disclosed. See Function Media, L.L.C. v. 

Google, Inc., 708 F.3d 1310, 1319 (Fed. Cir. 2013). 

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20 WILLIAMSON v. CITRIX ONLINE, LLC

For the foregoing reasons, we conclude that the “distributed learning control module” limitation fails to recite 

sufficiently definite structure and that the presumption 

against means-plus-function claiming is rebutted. We 

therefore agree with the district court that this limitation 

is subject to the provisions of 35 U.S.C. § 112, para. 6. 

3. Disclosure of Corresponding Structure

Having found that the “distributed learning control 

module” is subject to application of § 112, para. 6, we next 

determine whether the specification discloses sufficient 

structure that corresponds to the claimed function. We 

conclude that it does not. 

Construing a means-plus-function claim term is a 

two-step process. The court must first identify the 

claimed function. Noah Sys., Inc. v. Intuit Inc., 675 F.3d 

1302, 1311 (Fed. Cir. 2012). Then, the court must determine what structure, if any, disclosed in the specification 

corresponds to the claimed function. Where there are 

multiple claimed functions, as we have here, the patentee 

must disclose adequate corresponding structure to perform all of the claimed functions. Id. at 1318–19. If the 

patentee fails to disclose adequate corresponding structure, the claim is indefinite. Id. at 1311–12.

The district court identified three claimed functions 

associated with the “distributed learning control module” 

term: (1) receiving communications transmitted between 

the presenter and the audience member computer systems; (2) relaying the communications to an intended 

receiving computer system; and (3) coordinating the 

operation of the streaming data module. The district 

court then found that the specification fails to disclose 

structure corresponding to the “coordinating” function. 

On appeal, it is undisputed that the claimed “coordinating” function is associated with the “distributed learning 

control module.” Thus, we must ascertain whether adeCase: 13-1130 Document: 99-2 Page: 20 Filed: 06/16/2015
WILLIAMSON v. CITRIX ONLINE, LLC 21

quate structure corresponding to this function is disclosed 

in the specification. Id. at 1311.

Structure disclosed in the specification qualifies as 

“corresponding structure” if the intrinsic evidence clearly 

links or associates that structure to the function recited in 

the claim. Id. (citing B. Braun Med., Inc. v. Abbott Labs., 

124 F.3d 1419, 1424 (Fed. Cir. 1997)). Even if the specification discloses corresponding structure, the disclosure 

must be of “adequate” corresponding structure to achieve 

the claimed function. Id. at 1311–12 (citing In re Donaldson Co., 16 F.3d 1189, 1195 (Fed. Cir. 1994) (en banc)). 

Under 35 U.S.C. § 112, paras. 2 and 6, therefore, if a 

person of ordinary skill in the art would be unable to 

recognize the structure in the specification and associate 

it with the corresponding function in the claim, a meansplus-function clause is indefinite. Id. at 1312 (citing 

AllVoice Computing PLC v. Nuance Commc’ns, Inc., 504 

F.3d 1236, 1241 (Fed. Cir. 2007)).

The district court was correct that the specification of 

the ’840 patent fails to disclose corresponding structure. 

The written description of the ’840 patent makes clear 

that the distributed learning control module cannot be 

implemented in a general purpose computer, but instead 

must be implemented in a special purpose computer—a 

general purpose computer programmed to perform particular functions pursuant to instructions from program 

software. A special purpose computer is required because 

the distributed learning control module has specialized 

functions as outlined in the written description. See, 

e.g., ’840 patent col.5 ll.48–64. In cases such as this, 

involving a claim limitation that is subject to § 112, 

para. 6 that must be implemented in a special purpose 

computer, this court has consistently required that the 

structure disclosed in the specification be more than 

simply a general purpose computer or microprocessor. 

E.g., Aristocrat Techs. Austl. Pty Ltd. v. Int’l Game Tech., 

521 F.3d 1328, 1333 (Fed. Cir. 2008) (citing WMS GamCase: 13-1130 Document: 99-2 Page: 21 Filed: 06/16/2015
22 WILLIAMSON v. CITRIX ONLINE, LLC

ing, Inc. v. Int’l Game Tech., 184 F.3d 1339 (Fed. Cir. 

1999)). We require that the specification disclose an 

algorithm for performing the claimed function. Net MoneyIN, Inc. v. VeriSign, Inc., 545 F.3d 1359, 1367 (Fed. Cir. 

2008). The algorithm may be expressed as a mathematical formula, in prose, or as a flow chart, or in any other 

manner that provides sufficient structure. Noah, 675 

F.3d at 1312 (citing Finisar Corp. v. DirecTV Grp., Inc., 

523 F.3d 1323, 1340 (Fed. Cir. 2008)).

Williamson points to certain disclosures in the specification that, it claims, meet the § 112, para. 6 requirements. Williamson argues that the “distributed learning 

control module” controls communications among the 

various computer systems and that the “coordinating” 

function provides a presenter with streaming media 

selection functionality. These disclosures, however, are 

merely functions of the “distributed learning control 

module.” The specification does not set forth an algorithm 

for performing the claimed functions.

Williamson argues that figures 4 and 5 disclose the 

required algorithm. This is not the case. Figure 4 is a 

representative display from the presenter computer 

system under the direction of the “distributed learning 

control module.” ’840 patent col.7 ll.1–3. 

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WILLIAMSON v. CITRIX ONLINE, LLC 23

Id. figure 4. This display includes an address or uniform 

resource locator or URL field, a channel field, an “add this 

node” button, and a “back” link. Id. col.7 ll.5–7, 13–15, 

18–19. This is not a disclosure of an algorithm corresponding to the claimed “coordinating” function; it is a 

description of a presenter display interface.

Figure 5 similarly fails to disclose an algorithm, as it

is another representative display on the presenter computer system. Id. col.7 ll.20–24. This display allows the 

presenter to preview data before presenting it to the 

audience. Id. col.7 ll.32–34.

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24 WILLIAMSON v. CITRIX ONLINE, LLC

Id. figure 5. This figure contains a box listing the sources 

of data and a media window that displays the current feed 

received from the source of data selected in the list box. 

Id. col.7 ll.24–28. Again, this figure is a description of a 

presenter display interface; it is not a disclosure of an 

algorithm corresponding to the claimed functions. Williamson has failed to point to an adequate disclosure of 

corresponding structure in the specification.

Williamson points to the declaration of Dr. Souri to 

show that the ’840 patent discloses structure. The testimony of one of ordinary skill in the art cannot supplant 

the total absence of structure from the specification. 

Noah, 675 F.3d at 1312 (quoting Default Proof Credit 

Card Sys., Inc. v. Home Depot U.S.A., Inc., 412 F.3d 1291, 

1302 (Fed. Cir. 2005)). The prohibition against using 

expert testimony to create structure where none otherwise exists is a direct consequence of the requirement that 

the specification adequately disclose corresponding structure. Id. (quoting AllVoice Computing, 504 F.3d at 1240). 

Case: 13-1130 Document: 99-2 Page: 24 Filed: 06/16/2015
WILLIAMSON v. CITRIX ONLINE, LLC 25

Thus, the testimony of Dr. Souri cannot create structure 

where none otherwise exists.

Because the ’840 patent fails to disclose any structure 

corresponding to the “coordinating” function of the “distributed learning control module,” we affirm the judgment 

that claims 8–16 are invalid for indefiniteness under 35 

U.S.C. § 112, para. 2.

CONCLUSION

The district court erred in construing the “graphical 

display representative of a classroom” terms in claims 1–7 

and 17–24. The district court did not err in construing 

the term “distributed learning control module” in claims 

8–16 of the ’840 patent as a means-plus-function claim 

term lacking corresponding structure. We therefore 

vacate the final judgment of non-infringement with respect to claims 1–7 and 17–24 and affirm the final judgment of invalidity of claims 8–16. We remand for further 

proceedings consistent with this opinion. 

AFFIRMED-IN-PART, VACATED-IN-PART, AND 

REMANDED

COSTS

Each party shall bear its own costs for this appeal.

Case: 13-1130 Document: 99-2 Page: 25 Filed: 06/16/2015
United States Court of Appeals 

for the Federal Circuit ______________________ 

RICHARD A. WILLIAMSON, Trustee for At Home 

Bondholders Liquidating Trust,

Plaintiff-Appellant

v.

CITRIX ONLINE, LLC, CITRIX SYSTEMS, INC., 

MICROSOFT CORPORATION,

ADOBE SYSTEMS, INC.,

Defendants-Appellees

WEBEX COMMUNICATIONS, INC., CISCO WEBEX,

LLC, CISCO SYSTEMS, INC.,

Defendants-Appellees

INTERNATIONAL BUSINESS MACHINES 

CORPORATION,

Defendant-Appellee

______________________ 

2013-1130

______________________ 

Appeal from the United States District Court for the 

Central District of California in No. 11-CV-2409, Judge A. 

Howard Matz.

______________________ 

Case: 13-1130 Document: 99-2 Page: 26 Filed: 06/16/2015
2 WILLIAMSON v. CITRIX ONLINE, LLC

REYNA, Circuit Judge, concurring-in-part, dissenting-inpart, and additional views. 

This is the second time around for this case. In the 

first, Williamson I, I dissented from the majority conclusion that the “distributed learning control module” term

of claim 8 of the ’840 patent recites sufficient structure to 

keep the claim limitation “distributed learning control 

module” outside of the purview of 35 U.S.C. § 112, paragraph 6.1 

In this second time around, Williamson II, the majority reverses itself to conclude that the “distributed learning control module” term does not recite sufficient 

structure, is governed by 35 U.S.C. § 112, paragraph 6, 

and is indefinite under paragraph 2. Because this conclusion is the correct result, I concur. To explain my 

concurrence, I rely on the reasons I laid out in my dissent 

in Williamson I. 

The majority, however, continues to ignore critical evidence showing that an image of a visually depicted 

virtual classroom is required by claim 8 of the ‘840 patent. 

I dissent from that portion of this opinion. 

In addition, the majority embraces this case as an opportune vehicle to overrule as improper certain adjectives 

used in prior opinions in describing the § 112, paragraph 

6 presumption. See e.g., Inventio AG v. ThyssenKrupp 

Elevator Americas Corp., 649 F.3d 1350, 1360 (Fed. Cir. 

2011) (describing a “strong” presumption in favor of § 112, 

paragraph 6 application where a claim recites “means”). 

I cannot say that I disagree with those statements, but I 

question whether those statements sidestep underlying 

fundamental issues involving the development of func1 Williamson v. Citrix Online, LLC, 770 F.3d 1371, 

1380 (Fed. Cir. 2014)

 

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WILLIAMSON v. CITRIX ONLINE, LLC 3

tional claiming law since 1952 when 35 U.S.C. § 112, 

paragraph 6 was passed. 

For these and the reasons set forth below, 

I respectfully concur-in-part, dissent in part, and provide 

certain comments concerning means-plus-function claiming. 

I. The “Graphical Display” Limitations. 

The majority reverses the district court’s conclusion 

that the “graphical display representative of a classroom” 

terms require a pictorial map and construes the terms as 

“a graphical representation of an at least partially virtual 

space in which participants can interact.” While the 

majority is correct that the claims of the ’840 patent do 

not require a pictorial map, the majority’s construction 

ignores a critical limitation. As reviewed below, the 

specification and prosecution history make clear that the 

“graphical display representative of a classroom” terms 

are properly construed as requiring a visually depicted 

virtual classroom. 

During prosecution, the applicant explained that the 

invention is distinct from the prior art because the patent 

requires a “visual virtual classroom” displayed on both a 

first and second computer system:

Additionally, [the prior art] does not disclose the 

claimed feature of “creating a graphical display 

representative of the classroom” on a second computer system coupled to the network. The present 

invention allows both a first computer system (for 

example, the presenter computer system) and a 

second computer system (for example, an audience 

member) to view a graphical display of the classroom. This claimed feature of the present invention allows the audience members to interact in a 

visual virtual classroom environment with both 

the presenter and other audience members. 

Case: 13-1130 Document: 99-2 Page: 28 Filed: 06/16/2015
4 WILLIAMSON v. CITRIX ONLINE, LLC

By contrast, [the prior art] merely discloses “[as] 

the students log in, their seating locations in the 

classroom are shown by a highlighted icon in the 

classroom map on the teacher’s screen.” . . . [The 

prior art] does not teach or suggest displaying a 

graphical display representative of a classroom on 

a student’s screen. 

J.A. 1267-68 (original emphasis removed and emphases 

added). These statements in conjunction with the patent’s claim terms confirm the significance of displaying 

visually depicted virtual classroom. 

The “classroom metaphor” is used extensively in 

characterizing the operation, and touting the benefits, of 

the inventions embodied in the ’840 patent. The Abstract 

teaches that “[t]he classroom environment module provides a classroom metaphor having a podium and rows of 

seats to the presenter and audience computer systems.” 

’840 patent Abstract. The Summary of the Invention 

states that the drawbacks of the prior art are overcome 

“by a distributed learning system that uses industrystandard computer hardware and software linked by a 

network like the Internet to provide a classroom- or 

auditorium-like metaphor to at least one presenter and at 

least one audience member.” Id. col. 2 ll. 10-14. The 

patent further teaches that a “feedback region” on the 

presenter’s computer “preferably displays a graphical 

representation of the classroom” and the “classroom 

environment module” is used to provide “a classroom- or 

auditorium-like metaphor to the presenter and audience 

members.” Id. col. 3 ll. 11-13, col. 5 l. 67-col. 6 l. 1.

The repeated mention of the classroom metaphor 

within the context of the invention and the importance of 

a visually depicted virtual classroom in the prosecution 

history indicate that the “graphical display representative 

of a classroom” terms require a visually depicted virtual 

classroom. The construction derived by the majority 

Case: 13-1130 Document: 99-2 Page: 29 Filed: 06/16/2015
WILLIAMSON v. CITRIX ONLINE, LLC 5

reads out this important limitation that distinguishes the 

invention from the prior art. See Callicrate v. Wadsworth 

Mfg., Inc., 427 F.3d 1361, 1369 (Fed. Cir. 2005) (holding 

that it was error for the district court to read out a limitation clearly required by the claim language and specification). It is error to read a claim too broadly, as it is to 

read a claim too narrowly. See, e.g., Phillips v. AWH 

Corp., 415 F.3d 1303, 1321 (Fed. Cir. 2005). In reading 

out this important limitation on the “graphical display 

representative of a classroom” terms, the majority sidesteps our well established rules of claim construction, 

causing them to reach an erroneous result. 

II. Functional Claiming

The majority switches course from its prior decision, 

Williamson I, and now affirms the district court’s conclusion that the term “distributed learning control module” is 

governed by § 112 para. 6 and is indefinite under § 112 

para. 2 because the specification of the ’840 patent fails to 

disclose corresponding structure. The majority goes on to 

explicitly “overrule the characterization of th[e] presumption [that § 112 para. 6 does not apply when the term 

“means” is not used] as ‘strong.’” Maj. Op. at 15–16. 

While I agree with that conclusion, we stop short of 

addressing other equally fundamental concerns about 

functional claiming. 

Our use of § 112, para. 6 presumptions relies on a rigid framework, where a flexible one is arguably more apt. 

A “presumption” is a procedural tool that shifts the burden of proof on a substantive issue: if a basic fact is established, a court accepts a conclusion on the issue unless the 

presumption is rebutted with evidence that meets the 

presumption’s associated standard of proof. 1-301 WeinCase: 13-1130 Document: 99-2 Page: 30 Filed: 06/16/2015
6 WILLIAMSON v. CITRIX ONLINE, LLC

stein’s Federal Evidence § 301.02 (2015).2 Our § 112 

para. 6 presumptions come from the notion that, all else 

being equal, it is more likely that a party is covered by a 

statute when it uses the words of the statute. The use of 

formal presumptions, the argument goes, takes this 

concept to the extreme, supplying one substantive test for 

a claim that recites “means” and another for a claim that 

recites other non-structural terms like “module.” The 

statute admits no such variation, supplying only one test: 

is the element “expressed as a means or step for performing a specified function without the recital of structure, 

material, or acts in support thereof.” What arguably

changes is the weight we attach to different recitations in 

meeting this test: “means” weighs heavily, non-structural 

terms like “module” weigh a little less, and, at the other 

end of the spectrum, purely structural terms weigh heavily in the opposite direction. 

A related concern is, assuming that a presumption is 

the right tool to analyze the statute, should a presumption arise based on the word “means.” Almost twenty 

years ago, this court adopted a presumption that a claim 

term that recites “means” invokes § 112, para. 6. York 

2 One familiar presumption is the presumption of 

patent validity. Under this presumption, a court accepts 

the conclusion that an issued patent is valid absent clear 

and convincing evidence negating that presumption, i.e., 

evidence showing that the patent is invalid. Microsoft 

Corp. v. i4i Ltd. P'ship, 131 S. Ct. 2238, 2242 (2011); 

Commil USA, LLC v. Cisco Systems, Inc., No. 13-896, slip 

op. at 10–11 (U.S. May 26, 2015). I note that the majority 

opinion does not provide an associated standard of proof 

for the § 112 para. 6 presumptions. Indeed, I remain 

unconvinced that this court has applied a different standard of proof dependent on how the presumption is labeled 

or characterized. 

 

Case: 13-1130 Document: 99-2 Page: 31 Filed: 06/16/2015
WILLIAMSON v. CITRIX ONLINE, LLC 7

Products, Inc. v. Central Tractor Farm & Family Center, 

99 F.3d 1568 (Fed. Cir. 1996); Greenberg v. Ethicon EndoSurgery, Inc., 91 F.3d 1580 (Fed. Cir. 1996). Appellees’ 

petition for rehearing en banc argues that § 112 para. 6 

provides no basis for adopting a presumption that a claim 

term is governed by this statute when the term “means” is 

used. Appellees argue that “[w]hat started out as a 

straightforward issue of substance. . . has morphed into 

an issue of form.” Appellee’s Petition for Rehearing En 

Banc at 6. Appellees argue that “the text of [§ 112 para. 

6], the Supreme Court authority leading to it, and its 

legislative history universally confirm that [the statute] 

applies to all claims that do not recite sufficient structure 

for performing the recited function—regardless of whether the word ‘means’ is used.” Id. at 11. Moreover, the fact 

that the statute uses both terms—“means” and “step”—

would suggest that any presumption should apply to the

use of either word. Yet, it is arguably not clear to what 

extent this court attaches a presumption to the word 

“step.” 

Finally, it is generally accepted that § 112, para. 6

was passed in response to the Supreme Court’s decision in 

Halliburton Oil Well Cementing Co. v. Walker, 329 U.S. 1 

(1946). See Warner-Jenkinson Co., Inc. v. Hilton Davis 

Chem. Co., 520 U.S. 17, 27 (1997) (collecting cases); 

Technitrol, Inc. v. Control Data Corp., 550 F.2d 992, 998 

n. 5 (4th Cir. 1977). In Halliburton, the Supreme Court 

made the following observations in holding certain claims 

that recite “means” language invalid:

The language of the claim . . . describes this . . . 

element in the ‘new’ combination in terms of what 

it will do rather than in terms of its own physical 

characteristics or its arrangement in the new 

combination apparatus. We have held that a claim 

with such a description of a product is invalid . . . .

Id. at 8.

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8 WILLIAMSON v. CITRIX ONLINE, LLC

Arguably, this rationale applies to functional claiming 

generally, not just to claims that recite “means.” Indeed, 

the Halliburton Court relied on precedent invalidating 

functional claims that did not recite the term “means.” 

Id. at 9 (citing Holland Furniture Co. v. Perkins Glue Co., 

277 U.S. 245, 256–57 (1928).) The continued viability of 

this rationale, and its impact on how this Court applies 

§ 112, para. 6 merits attention. 

In sum, my view is that perhaps we need to revisit our 

judicially-created § 112, para. 6 presumptions. 

Case: 13-1130 Document: 99-2 Page: 33 Filed: 06/16/2015
United States Court of Appeals 

for the Federal Circuit ______________________ 

RICHARD A. WILLIAMSON, Trustee for At Home 

Bondholders Liquidating Trust,

Plaintiff-Appellant

v.

CITRIX ONLINE, LLC, CITRIX SYSTEMS, INC., 

MICROSOFT CORPORATION,

ADOBE SYSTEMS, INC.,

Defendants-Appellee

WEBEX COMMUNICATIONS, INC., CISCO WEBEX,

LLC, CISCO SYSTEMS, INC.,

Defendants-Appellees

INTERNATIONAL BUSINESS MACHINES 

CORPORATION,

Defendant-Appellee

______________________ 

2013-1130

______________________ 

Appeal from the United States District Court for the 

Central District of California in No. 11-CV-2409, Judge A. 

Howard Matz.

______________________ 

Case: 13-1130 Document: 99-2 Page: 34 Filed: 06/16/2015
2 WILLIAMSON v. CITRIX ONLINE, LLC

NEWMAN, Circuit Judge, dissenting.

I respectfully dissent from the en banc ruling that is 

inserted into this panel opinion at Section II.C.1. The 

court en banc changes the law and practice of 35 U.S.C. 

§ 112 paragraph 6, by eliminating the statutory signal of 

the word “means.” The purpose of this change, the benefit, is obscure. The result, however, is clear: additional 

uncertainty of the patent grant, confusion in its interpretation, invitation to litigation, and disincentive to patentbased innovation.

Curiously, the court acknowledges that it “has long 

recognized the importance of the presence or absence of 

the word ‘means.’” Maj. Op. at 13. Nonetheless, the court 

rejects the meaning and usage of “means” to signal 

means-plus-function claim construction. The court now 

overrules dozens of cases referring to a “strong presumption” of means-plus-function usage, and goes to the opposite extreme, holding that this court will create such 

usage from “[g]eneric terms such as ‘mechanism,’ ‘element,’ ‘device,’ and other nonce words.” Maj. Op. at 17. 

In the case before us, the so-called “nonce” word is “module.” Thus the court erases the statutory text, and holds 

that no one will know whether a patentee intended 

means-plus-function claiming until this court tells us.

I dissent from the majority’s reasoning and the majority’s holding that “distributed learning control module” 

falls under paragraph 6. I express no opinion on the 

ultimate validity of the claim; the claim must stand or fall 

on its merit, but does not fall under paragraph 6.

I urge the court to recognize that it is the applicant’s 

choice during prosecution whether or not to invoke paragraph 6, and the court’s job is to hold the patentee to his 

or her choice. This approach is clear, easy to administer 

by the USPTO in examination and the courts in litigation, 

and does no harm, for patent applicants know how to 

invoke paragraph 6 if they choose.

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WILLIAMSON v. CITRIX ONLINE, LLC 3

The statute is clear

When the statute is clear, judicial interpretation is 

unnecessary. See Sebelius v. Cloer, 133 S. Ct. 1886, 1896 

(2013) (“[R]ules of thumb give way when the words of a 

statute are unambiguous . . .”) (internal quotations omitted); Arlington Cent. Sch. Dist. Bd. of Educ. v. Murphy, 

548 U.S. 291, 296 (2006) (“When the statutory ‘language 

is plain, the sole function of the courts—at least where the 

disposition required by the text is not absurd—is to 

enforce it according to its terms.’”) (quoting Hartford 

Underwriters Ins. Co. v. Union Planters Bank, N.A., 530 

U.S. 1, 6 (2000)); Hughes Aircraft Co. v. Jacobson, 525 

U.S. 432, 438 (1999) (“As in any case of statutory construction, our analysis begins with the language of the 

statute. And where the statutory language provides a 

clear answer, it ends there as well.”) (internal citations 

and quotations omitted); Estate of Cowart v. Nicklos 

Drilling Co., 505 U.S. 469, 475 (1992) (“[W]hen a statute 

speaks with clarity to an issue judicial inquiry into the 

statute's meaning, in all but the most extraordinary 

circumstance, is finished.”).

35 U.S.C. § 112 paragraph 6 authorizes and limits the

claiming of a function:

¶ 6 An element in a claim for a combination may 

be expressed as a means or step for performing 

a specified function without the recital of structure, material, or acts in support thereof, and such 

claim shall be construed to cover the corresponding structure, material, or acts described in 

the specification and equivalents thereof.

(Boldface added. Paragraph 6 was redesignated paragraph “f” in 2012 – I retain the earlier designation here, 

for concordance with precedent.).

The statute is clear. To claim an element by the function performed, the element is “expressed as” a “means 

Case: 13-1130 Document: 99-2 Page: 36 Filed: 06/16/2015
4 WILLIAMSON v. CITRIX ONLINE, LLC

for,” as the statute provides. The court’s holding that 

“distributed learning control module” is “a means-plusfunction claim term despite the absence of the word 

‘means’,” maj. op. at 16, is not only unclear – it also violates the statute.

The signal “means for” is clear – and is clearly 

understood 

When the statutory signal “means for” is given, the 

entire patent-concerned community: the patent attorney, 

the patent examiner, the competitor, the infringer, the 

inventor, and the judge, know “the subject matter which 

the applicant regards as his invention,” 35 U.S.C. § 112 

¶ 2, and know how the means-plus-function term is 

required to be construed. When an applicant claims a 

“means for” performing a function, the statute limits the 

scope of the claim to the structure in the specification and 

its equivalents. With today’s en banc change of law, as 

the case sub judice illustrates, everyone must guess 

whether the claimed “module” is claimed as a function or 

an apparatus or something else, and whether it is to be 

limited by the “structure, material, or acts described in 

the specification and equivalents thereof.” 35 U.S.C. 

§ 112, ¶ 6.

Until today, the signal “means for” instructed the 

claim interpretation. There was no ambiguity about how 

the claim was to be interpreted. I discern no groundswell 

for this change in the law of claiming – indeed, the public 

voice has been silent. I know of no legal or public interest 

served by introducing this uncertainty into claim construction. I urge the court to restore this claim construction to its clear and effective role.

Legislation by footnote

An unheralded footnote, announcing en banc change 

of law, without notice to and participation of the interested public, is not the optimum judicial path. There is 

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indeed a need for judicial consistency concerning the 

construction of means-plus-function claims. The answer 

is not to strain the statute and reject consistency, but to 

enforce the statute as it is written.

We should act en banc to correct this departure from 

statute. If the statute is to be changed, that is not the 

judicial prerogative. Indeed, it is noteworthy that in eight 

years of congressional study of proposals for legislative 

change, culminating in the America Invents Act of 2012, 

the legislative record shows no proposal to depart from 

the “strong presumption” embodied in section 112 paragraph 6 and the statutory signal “means for.”

The burden is on the applicant, not the judge

The burden of determining whether paragraph 6 applies to a particular element is on the applicant, not the 

court. As the Faber/Landis treatise states: “To be sure you 

are under section 112, paragraph 6, use the pure ‘means 

for . . .’ Other words lead to ambiguity and the need for 

the court to decide. Use of clear structure words avoids 

ambiguity.” ROBERT C. FABER, LANDIS ON MECHANICS OF 

PATENT CLAIM DRAFTING at 3-201 (5th ed. 2008).

The Donner treatise teaches by example:

For example, suppose an invention relates to a 

new television set. The television set includes a 

new transistor-based picture tube, as well as other 

new features. The picture tube can be recited two 

ways in the claim for the television:

Standard claim element format:

A television, comprising:

A picture tube; . . .

Means-plus-function format:

A television comprising:

Picture tube means for displaying a television picture; . . .

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IRAH H. DONNER, PATENT PROSECUTION: PRACTICE AND 

PROCEDURE BEFORE THE U.S. PATENT AND TRADEMARK 

OFFICE at 46-47 (2d ed. 1999).

My colleagues protest that the statutory presumption 

of “means” “has resulted in a proliferation of functional 

claiming untethered to § 112, para. 6 and free of the 

strictures set forth in the statute.” Maj. Op. at 15. This is 

an indictment of the court’s fidelity to the statute, not a 

flaw in the statute itself. The court’s reasoning today that 

there is no “algorithm” for “module” in the specification,

and the word “module” is a “nonce word” for “means,” and 

thus the claim is written in accordance with paragraph 6, 

is not easy to fathom.

The enactment in 1952

This paragraph was enacted to overturn several Supreme Court rulings rejecting “functional” claiming. The 

statute authorizes claiming a function or step in a combination, while safeguarding against the Court’s stated 

concerns. P.J. Federico’s Commentary explains:

The last paragraph of section 112 relating to socalled functional claims is new. It provides that 

an element of a claim for a combination (and a 

combination may be not only a combination of mechanical elements, but also a combination of substances in a composition claim, or steps in a 

process claim) may be expressed as a means or 

step for performing a specified function, without 

the recital of structure, material or acts in support 

thereof. 

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P.J. Federico, Commentary on the New Patent Act, in 35 

U.S.C.A. 1, 25 (West 1954), reprinted in 75 J. PAT. &

TRADEMARK OFF. SOC’Y 161 (1993).1

The Commentary made clear that the statute was 

intended to overrule some Court decisions:

It is unquestionable that some measure of greater 

liberality in the use of functional expressions in 

combination claims is authorized than had been 

permitted by some court decisions and that decisions such as that in Halliburton Oil Well Cementing Co. v. Walker, 67 S.Ct. 6, 329 U.S. 1, 91 L. Ed. 

3 (1946), are modified or rendered obsolete, but 

the exact limits of the enlargement remain to be 

determined.

Id. Federico explained that paragraph 6 enlarges the 

opportunity to claim a function, but limits how that 

function is supported and construed:

The paragraph ends by stating that such a claim 

shall be construed to cover the corresponding 

structure, material, or acts described in the specification and equivalents thereof. This relates 

primarily to the construction of such claims for 

the purpose of determining when the claim is infringed (note the use of the word “cover”), and 

1 See Giles S. Rich, Congressional Intent—or, Who 

wrote the Patent Act of 1952?, in PATENT PROCUREMENT 

AND EXPLOITATION 61, 66 (BNA Inc., 1963) (“Mr. Federico 

received a letter . . . saying the [House] committee requested him to undertake the preparation of ‘an overall 

patent revision bill’ at his earliest convenience. . . .”); see 

also Louis S. Zarfas, Notes from the Editor, J. PAT. &

TRADEMARK OFF. SOC’Y 160 (1993) (“Examiner-in-Chief 

Federico was the primary author of the Patent Act of 

1952.”).

 

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would not appear to have much, if any, applicability in determining the patentability of such claims 

over the prior art, that is, the Patent Office is not 

authorized to allow a claim which “reads on” the 

prior art.

Id. at 26.

Thus this paragraph of the 1952 Act overruled the 

Halliburton case, which had been supported by earlier 

precedent, as the Court discussed. Halliburton, 329 U.S. 

at 10 (citing General Elec. Co. v. Wabash Appliance Corp., 

304 U.S. 364, 371 (1938) for the proposition that claims 

are indefinite for using “conveniently functional language 

at the exact point of novelty.”).

This paragraph established that an inventor could 

claim a function, and the “means for” signal entered the 

patent lexicon, where it has reposed ever since, as a 

universally understood signal of a functional claim.

The Examination Guidelines

The PTO Examination Guidelines instruct examiners 

and practitioners in accordance with law. The 2000 

Guidelines dealt with means-plus-function claiming as 

follows:

The PTO must apply 35 U.S.C. 112 ¶6 in appropriate cases, and give claims their broadest reasonable interpretation, in light of and consistent

with the written description of the invention in 

the application. [2] Thus, a claim limitation will 

be interpreted to invoke 35 U.S.C. 112 ¶ 6 if it 

meets the following 3-prong analysis:

(1) The claim limitations must use the 

phrase “means for” or “step for;”

(2) the “means for” or “step for” must be 

modified by functional language; and 

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(3) the phrase “means for” or “step for” 

must not be modified by structure, material or 

acts for achieving the specified function.

Supplemental Examination Guidelines for Determining 

the Applicability of 35 U.S.C. 112 ¶ 6, 65 Fed. Reg. 38510, 

38514 (June 21, 2000). Endnote 2 cites In re Donaldson

for “stating that 35 U.S.C. 112 ¶ 6 sets a limit on how 

broadly the PTO may construe means-plus-function 

language under the rubric of ‘reasonable interpretation’.” 

Id. at 38515. The Guidelines further explained:

With respect to the first prong of this analysis, a 

claim element that does not include the phrase 

“means for” or “step for” will not be considered to 

invoke 35 U.S.C. 112 ¶ 6. If an applicant wishes 

to have the claim limitation treated under 35 

U.S.C. 112 ¶ 6, applicant must either: (1) Amend 

the claim to include the phrase “means for” or 

“step for” in accordance with these interim guidelines; or (2) show that even though the phrase 

“means for” or “step for” is not used, the claim limitation is written as a function to be performed 

and does not provide any structure, material, or 

acts which would preclude application of 35 U.S.C. 

112 ¶ 6.

Id. at 38514.

The 2000 Guidelines place the burden for invoking 

paragraph 6 on the applicant by way of the “means” 

signal. Id. at 38514 (citing Notice, Means or Step Plus 

Function Limitation under 35 U.S.C. 112, ¶6, 1162 

OFFICIAL GAZETTE U.S. PAT. OFF. 59 (May 17, 1994)). The 

Revised Examination Guidelines in 2011 attempted to 

incorporate this court’s intervening decisions, for the 

Federal Circuit had begun its retreat from clarity. See

Supplementary Examination Guidelines for Determining 

Compliance With 35 U.S.C. 112 and for Treatment of 

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Related Issues in Patent Applications, 76 Fed. Reg. 7162 

(Feb. 9, 2011).

Examiners are now instructed to scrutinize claims for 

“a nonce word or verbal construct that is not recognized as 

the name of a structure.” Id. at 7167 (citing Lighting 

World, 382 F.3d at 1360). The examiner is instructed to 

“determine whether the claim limitation uses a nonstructural term (a term that is simply a substitute for the 

term “means for”).” Id. (citing Welker Bearing Co. v. PHD, 

Inc., 550 F.3d 1090, 1096 (Fed. Cir. 2008). The examiner 

must guess whether the term is intended as a meansplus-function term, now that the court holds that the 

signal “means for” need not be used. Paragraph 6 has 

morphed from a clear legal instruction into a litigator’s 

delight.

Federal Circuit precedent, on and off

This court has recognized that the absence of “means 

for” signals the patentee’s intent not to invoke section 

112, para. 6, and that this intent should not be rejected 

lightly. E.g., Apple Inc. v. Motorola, Inc., 757 F.3d 1286, 

1297 (Fed. Cir. 2014) (“We have repeatedly characterized 

this presumption as ‘strong’ and ‘not readily overcome’ 

and, as such, have ‘seldom’ held that a limitation without 

recitation of “means” is a means-plus-function limitation.”); Flo Healthcare Solutions, LLC v. Kappos, 697 F.3d 

1367, 1374 (Fed. Cir. 2012) (“Our cases make clear ... that 

the presumption flowing from the absence of the term 

‘means' is a strong one that is not readily overcome.”) 

(quoting Lighting World, Inc. v. Birchwood Lighting, Inc., 

382 F.3d 1354, 1358 (Fed. Cir. 2004)); Inventio AG v. 

ThyssenKrupp Elevator Americas Corp., 649 F.3d 1350, 

1356 (Fed. Cir. 2011) (“Thus, the presumption flowing 

from the absence of the term “means” is a strong one that 

is not readily overcome”); Al–Site Corp. v. VSI International, Inc., 174 F.3d 1308, 1318 (Fed. Cir. 1999) (“[W]hen 

an element of a claim does not use the term “means,” 

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treatment as a means-plus-function claim element is 

generally not appropriate.”); Personalized Media Communications, LLC v. International Trade Commission, 161 

F.3d 696, 704 (Fed. Cir. 1998) (“failure to use the word 

“means” creates a presumption that § 112, ¶ 6 does not 

apply.”). On this weighty precedent, the court’s en banc 

rejection of this simple signal is not readily understood.

The en banc court still permits use of the “means” signal, although without a “strong presumption” of significance. The result is fresh uncertainty, for the judge can 

invoke paragraph 6 although the patentee chose otherwise and wrote the specification and claims on a different 

legal standard.

All claims must meet the requirements of patentability

The court states its concern with overly broad interpretation of software claims. The court is not powerless to 

require software claims to comply with the statutory 

requirements of description, enablement, definiteness, 

unobviousness, etc. If there have been abuses, as the 

majority states, the remedy is not to eliminate the statute, but to apply the statute.

Today’s ruling is an example. The court holds that 

the clause “distributed learning control module” is subject 

to paragraph 6 because “module” is a “nonce word.” The 

court then finds no “algorithm” for “module” in the specification, and invalidates the claim for failing to comply with 

paragraph 6. However, contrary to the apparent belief of 

the majority, the presence or absence of the paragraph 6 

signal does not affect the requirements of patentability.

All claims must meet the requirements of patentability. Paragraph 6 is a statute of authorization and limitation; it does not annul the other provisions of the statute. 

The problem with today’s ruling is that the court has 

rejected the rigor and simplicity of paragraph 6 and the 

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patentee’s intent, replacing it with arbitrary judicial

subjectivity.

CONCLUSION

Paragraph 6 was designed to authorize and provide 

the rules for claiming a functional element or step. No 

purpose is served by discarding the statutory signal. The 

result is further inroad into stability of claim construction. I respectfully dissent.

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