United States Court of Appeals for the Federal Circuit 

2007-1201, -1239 

SYMANTEC CORPORATION, 

Plaintiff/Counterclaim DefendantAppellant, 

and 

HILGRAEVE, INCORPORATED, 

 Plaintiff/Counterclaim Defendant, 

v. 

COMPUTER ASSOCIATES INTERNATIONAL, INC., 

Defendant/CounterclaimantCross Appellant, 

and 

RICHARD B. LEVIN, 

 

 Counterclaimant-Cross Appellant. 

David A. Nelson, Latham & Watkins LLP, of Chicago, Illinois, argued for 

plaintiff/counterclaim defendant-appellant. With him on the brief was Mark A. Flagel, of 

Los Angeles, California. On the brief were Daniel A. Boehnen, George I. Lee, and 

Jeffrey A. Steck, McDonnell Boehnen Hulbert & Berghoff LLP, of Chicago, Illinois. Of 

counsel on the brief was Joseph Fitzgerald, Symantec Corp., of Cupertino, California. 

 

Michael A. Nicodema, Greenberg Traurig LLP, of New York, New York, argued 

for defendant/counterclaimant-cross appellant. With him on the brief was Gaston 

Kroub. 

Gerry J. Elman, Elman Technology Law, P.C, of Swarthmore, Pennsylvania, for 

counterclaimant-cross-appellant. 

Appealed from: United States District Court for the Eastern District of Michigan 

Chief Judge Bernard A. Friedman 
 

United States Court of Appeals for the Federal Circuit 

 

2007-1201, -1239 

SYMANTEC CORPORATION, 

 Plaintiff/Counterclaim 

Defendant-Appellant, 

and 

HILGRAEVE, INCORPORATED, 

 Plaintiff/Counterclaim Defendant, 

v. 

COMPUTER ASSOCIATES INTERNATIONAL, INC., 

 Defendant/CounterclaimantCross Appellant, 

and 

RICHARD B. LEVIN, 

 Counterclaimant-Cross Appellant. 

Appeals from the United States District Court for the Eastern District of Michigan in case 

no. 02-CV-73740, Chief Judge Bernard A. Friedman. 

 ___________________________ 

 DECIDED: April 11, 2008 

 ___________________________ 

Before GAJARSA, LINN, and DYK, Circuit Judges. 

DYK, Circuit Judge. 

 In this patent infringement suit, appellant Symantec Corporation (“Symantec”) 

appeals from the district court’s grant of summary judgment of non-infringement of 
claims 1-20 of the asserted patent, U.S. Patent No. 5,319,776 (“the ’776 patent”). 

Symantec Corp. v. Computer Assocs. Int’l, Inc., No. 02-CV-73740-DT (E.D. Mich. Aug. 

31, 2006) (reports and recommendations of magistrate judge).1

 Computer Associates 

International, Inc. (“CA”), the accused infringer, cross-appeals from the district court’s 

grant of summary judgment on: (1) the defense of laches; (2) inequitable conduct; (3) 

invalidity over the prior art; and (4) inventorship. Id. Richard B. Levin (“Levin”) crossappeals from the district court’s grant of summary judgment that he was not a coinventor of the ‘776 patent. Id.

Because we find that the district court erred in its construction of the claim terms 

“a method of screening data as it is being transferred,” “destination storage medium,” 

“computer,” and “computer system,” we vacate and remand as to non-infringement and 

invalidity. We dismiss CA’s cross-appeal as to laches as improper, but we treat laches 

as an alternative ground for affirming the judgment. We affirm the district court’s 

decision on laches, inequitable conduct, and inventorship. 

BACKGROUND 

 The ’776 patent is here for the third time. The patent is directed to the “In Transit 

Detection of Computer Virus with Safeguard,” and is described in detail in our earlier 

opinions. See Hilgraeve Corp. v. McAfee Assocs., Inc., 224 F.3d 1349, 1350-52 (Fed. 

Cir. 2000) (“Hilgraeve I”); Hilgraeve Corp. v. Symantec Corp., 265 F.3d 1336, 1338-41 

 1

 The citations are to the reports and recommendations of the magistrate 

judge. The district court adopted these reports and recommendations in their entirety 

by order. Symantec, No. 02-CV-73740-DT (E.D. Mich. Jan. 23, 2007) (order accepting 

and adopting magistrate judge’s reports and recommendations). 

2007-1201, -1239 2 
(Fed. Cir. 2001) (“Hilgraeve II”). Briefly, the ’776 patent discloses a method of scanning 

for and detecting computer viruses embedded in data files that are downloaded or 

copied from a remote server (e.g., via the internet) onto a computer. Critically, the 

claimed virus-scan operates before the downloaded or copied data files are accessible 

to the computer’s operating system, thereby allowing the software to block access to 

those files early enough to prevent the embedded viruses from spreading and infecting 

the computer. The ’776 patent includes claims 1-20, of which claim 1 and claim 18 are 

independent. Claim 1 is representative: 

1. In a system for transferring digital data for storage in a computer 

storage medium, a method of screening the data as it is being transferred

and automatically inhibiting the storage of screened data containing at 

least one predefined sequence, comprising the steps of: 

causing a quantity of digital data resident on a source storage medium to 

be transferred to a computer system having a destination storage medium; 

receiving and screening the transferred digital data prior to storage on the 

destination storage medium to determine if at least one of a plurality of 

predefined sequences are present in the digital data received; and 

in response to said screening step: 

(a) automatically causing the screened digital data to be stored on 

said destination storage medium if none of the plurality of 

predefined sequences are present, and 

(b) automatically inhibiting the screened digital data from being 

stored on said destination storage medium if at least one 

predefined sequence is resent. 

’776 patent, col.17 ll.9-29 (emphases added). 

 In the ’776 patent’s two prior appearances before this court, the central issue was 

whether the accused virus-scanning products scanned incoming data files prior to 

storage. In Hilgraeve I, Hilgraeve, the original assignee of the ’776 patent, brought a 

2007-1201, -1239 3 
patent infringement suit against McAfee Associates (“McAfee”) for its VirusScan 

product. 224 F.3d at 1350. The district court granted summary judgment of noninfringement to McAfee, and Hilgraeve appealed. Id. In that appeal, the parties did not 

dispute the construction of the claim term “storage,” which the district court had 

construed as occurring “when the incoming digital data is sufficiently present on the 

destination storage medium, and accessible by the operating system or other programs, 

so that any viruses contained in the data can spread and infect the computer system.” 

Id. at 1351. 

 In Hilgraeve II, Hilgraeve asserted the same ’776 patent in a separately filed 

action against Symantec. 265 F.3d at 1338. The district court granted summary 

judgment of non-infringement to Symantec, and Hilgraeve appealed. Id. On appeal, 

Hilgraeve challenged the district court’s construction of the term “storage,” which 

differed from the construction in Hilgraeve I because it did not include the “accessible by 

the operating system or other programs” language. Id. at 1341. Symantec argued that 

the term should be construed to occur “when the data become physically present (i.e., 

magnetically recorded) on the storage medium.” Id. We rejected Symantec’s 

construction and adopted Hilgraeve’s construction (which was identical to the district 

court’s construction in Hilgraeve I) of “storage,” holding that “storage” occurred “when 

the incoming digital data [are] sufficiently present on the destination storage medium 

and accessible by the operating system or other programs so that any viruses contained 

in the data can spread and infect the computer system.” Id. at 1342. 

Subsequent to our decision in Hilgraeve II, Symantec settled its dispute with 

Hilgraeve, and, as part of that settlement, purchased Hilgraeve’s interest in the ‘776 

2007-1201, -1239 4 
patent. Hilgraeve had previously filed a new infringement action against CA, alleging 

infringement of claims 1-20 of the ’776 patent. The district court then substituted 

Symantec as the plaintiff. 

CA, the accused infringer here, develops and sells a number of antivirus software 

products. The accused products are: (1) the eTrust EZ and eTrust products (collectively 

“the EAV products”), which employ both an incoming and outgoing scan mode; (2) the 

ARCserve product, which is designed to restore data from a backup media where the 

data had previously been archived; and (3) the Gateway products, which operate as a 

proxy between a user’s personal computer and an unattended gateway computer. 

CA’s initial pleadings denied infringement and asserted affirmative defenses and 

counterclaims for invalidity and non-infringement. Subsequently, CA amended its 

pleadings to add affirmative defenses (including a defense of laches) and counterclaims 

for unenforceability of the ’776 patent due to inequitable conduct, and for invalidity of the 

’776 patent under 35 U.S.C. § 256 for failing to name alleged co-inventor Levin. The 

district court also granted Levin’s motion to intervene as a party and assert a claim for 

co-inventorship of the ’776 patent. 

 As discussed below, the district court construed the terms “a method of 

screening the data as it is being transferred,” “computer system,” and “destination 

storage medium”—the critical claim terms on appeal—in an order dated March 16, 

2005. Based on its constructions of those terms, it granted summary judgment to CA of 

non-infringement on the EAV products and the ARCserve product. Although it did not 

grant summary judgment on the Gateway products, the parties stipulated to noninfringement of the Gateway products under the district court’s claim construction. The 

2007-1201, -1239 5 
district court also granted summary judgment to Symantec on invalidity, holding that the 

’776 patent was not anticipated or obvious in view of several prior art references. 

Finally, in separate orders, the district court granted summary judgment to Symantec 

on: CA’s affirmative defense of laches; CA’s claim that the ’776 patent was 

unenforceable based on inequitable conduct; and CA and Levin’s claim that Levin was a 

joint inventor of the ’776 patent. Symantec timely appealed; CA and Levin timely crossappealed. We have jurisdiction pursuant to 28 U.S.C. § 1295(a)(1), except as to CA’s 

improper cross-appeal on the issue of laches. 

DISCUSSION 

 We review summary judgment decisions without deference, reapplying the 

standard used by the district court. Innogenetics, N.V. v. Abbott Labs., 512 F.3d 1363, 

1378 (Fed. Cir. 2008). “Under that standard, summary judgment must be granted 

when, drawing all reasonable inferences in favor of the non-movant, there is no genuine 

issue as to any material fact and no reasonable jury could return a verdict for the nonmovant.” Id.

I 

A 

Symantec’s primary challenge is to the district court’s determination that the term 

“a method of screening the data as it is being transferred,” appearing in the preambles 

to the claims, was a claim limitation, and its construction of that phrase to mean “a 

method of screening the data while it is being moved or copied and before the data is 

stored to the computer storage medium.” J.A. at 15. These determinations bear 

2007-1201, -1239 6 
directly on the infringement analysis of each of the accused CA products. The dispute 

centers on whether the claims cover methods that do not screen data until after that 

data is written to a storage medium but do conduct screening “prior to storage,” i.e., 

before the data is accessible to the operating system or to other computer programs. 

Under the district court’s construction, antivirus programs that screen data at any 

time after that data is written to the storage medium (e.g., the computer’s hard drive), 

but before it becomes accessible to the operating system or to other computer 

programs, fall outside the scope of the “as it is being transferred” limitation, even if 

screening is completed entirely before the data becomes accessible. This construction, 

Symantec argues, is in direct conflict with our earlier decision in Hilgraeve II, where we 

construed the term “storage” to occur “when the incoming digital data is sufficiently 

present on the destination storage medium and accessible by the operating system or 

other programs so that any viruses contained in the data can spread and infect the 

computer system.” 265 F.3d at 1342. That construction of the term “storage,” 

Symantec argues, would have no meaning if the claim term “a method of screening data 

as it is being transferred” were construed to mean that the virus scanning must occur 

entirely before any data is written to the storage medium. 

 On appeal, CA does not dispute the binding effect of our earlier construction of 

the term “storage” in Hilgraeve II. Instead, CA contends that our earlier panel decision 

did not address the claim term “a method of screening data as it is being transferred,” 

appearing in the preamble, now at issue. That term, it argues, is a separate claim 

limitation that was added independently to overcome prior art virus-detection methods. 

2007-1201, -1239 7 
Claim construction is a question of law that we review without deference. Cybor 

Corp. v. FAS Techs., Inc., 138 F.3d 1448, 1456 (Fed. Cir. 1998) (en banc). 

Because the disputed term appears in the preamble to claim 1, we must first 

determine whether it is in fact a separate limitation. In general, a preamble is construed 

as a limitation “if it recites essential structure or steps, or if it is ‘necessary to give life, 

meaning, and vitality’ to the claim.” Catalina Mktg. Int’l, Inc. v. Coolsavings.com, Inc., 

289 F.3d 801, 808 (Fed. Cir. 2002) (quoting Pitney Bowes, Inc. v. Hewlett-Packard Co., 

182 F.3d 1298, 1305 (Fed. Cir. 1999)). A preamble is not limiting, however, “’where a 

patentee defines a structurally complete invention in the claim body and uses the 

preamble only to state a purpose or intended use for the invention.’” Id. (quoting Rowe 

v. Dror, 112 F.3d 473, 478 (Fed. Cir. 1997)). In Catalina, we identified several 

guideposts to aid in determining whether a preamble should be given limiting weight. 

For example, “clear reliance on the preamble during prosecution to distinguish the 

claimed invention from the prior art transforms the preamble into a claim limitation 

because such reliance indicates use of the preamble to define, in part, the claimed 

invention.” Id. Absent clear reliance on the preamble in the prosecution history, or in 

situations where it is necessary to provide antecedent basis for the body of the claim, 

the preamble “generally is not limiting.” Id. at 809. Thus, in general, the purpose of a 

claim preamble is to give context for what is being described in the body of the claim; if 

it is reasonably susceptible to being construed to be merely duplicative of the limitations 

in the body of the claim (and was not clearly added to overcome a rejection), we do not 

construe it to be a separate limitation. 

2007-1201, -1239 8 
Here, the only basis for the district court’s departure from the general rule was 

the notion that the “as it is being transferred” language was added separately from the 

“prior to storage” limitation to overcome the prior art. However, the district court erred in 

its description of the prosecution history. The prosecution history is clear that both 

terms were added concurrently to overcome the same prior art. The “as it is being 

transferred” language did not have its own independent significance. The prosecution 

history fails to demonstrate “clear reliance on the preamble during prosecution to 

distinguish the claimed invention from the prior art.” See id. at 808.2 

CA argues alternatively that the district court’s construction was nonetheless 

correct because the “as it is being transferred” term and the “prior to storage” term 

cannot have the same meaning—they must each be given a distinct construction. 

Although CA is correct that when construing terms in the body of a claim, the general 

assumption is that different terms have different meanings, Applied Medical Resources 

Corp. v. United States Surgical Corp., 448 F.3d 1324, 1333 n.3 (Fed. Cir. 2006), the 

same generally is not true for terms in the preamble. The use of different language in 

the preamble than in the body of the claims does not suggest that the preamble 

imposes a limitation. Rather it is assumed that the preamble language is duplicative of 

the language found in the body of the claims or merely provides context for the claims, 

 2

 CA also argues that the “prior to storage” requirement was already in the 

claim before amendment because the claim referred to “inhibiting the digital data of said 

transmission from being stored on said destination storage medium if at least one 

predefined sequence is present.” J.A. at 7439. Even if the original claim language could 

be construed to include the “prior to storage” limitation, the applicant chose not to rely 

on that language, and added additional specific “prior to storage” language to overcome 

the prior art. Under these circumstances, we must assume that the additional language 

had significance in distinguishing the prior art. 

2007-1201, -1239 9 
absent any indication to the contrary in the claims, the specification or the prosecution 

history. Here, there is nothing in the claims, the specification or the prosecution history 

that suggests that the preamble language “as it is being transferred” has any different 

meaning than “prior to storage.”3

Indeed, if the term “as it is being transferred” is to be read consistently with our 

prior construction of the term “storage,” the claim term “as it is being transferred” can 

only mean that virus scanning occurs “prior to storage.”4

 Any other construction of that 

term would vitiate the meaning that we previously gave to the term “storage” in 

Hilgraeve I and Hilgraeve II. See Kimberly-Clark Corp. v. Fort Howard Paper Co., 772 

F.2d 860, 863 (Fed. Cir. 1985) (“[S]tatements in opinions of this court must be read 

harmoniously with prior precedent, not in isolation.”). There would simply be no reason 

to construe “storage” to mean that scanning can occur after it is written to the computer 

but before it is accessible to other programs if the term “as it is being transferred” 

requires scanning to occur completely before any data is written to the computer. 

 We conclude that the term “as it is being transferred” simply means “prior to 

storage.” Given our previous construction of the term “storage” in Hilgraeve II, the term 

“as it is being transferred” must mean “before the incoming digital data is sufficiently 

 3

 CA relies on expert testimony that the preamble and the body of the claim 

should be interpreted as requiring separate limitations. That testimony does not, 

however, identify an accepted meaning in the field. To the extent that the testimony 

merely gives the expert’s opinion as to claim construction, we attribute it no weight. See

Sinorgchem Co., Shandong v. Int’l Trade Comm'n, 511 F.3d 1132, 1137 n.3 (Fed. Cir. 

2007). 

4

 This appears to have been our assumption in Hilgraeve I, where we 

stated: “The claimed invention scans a body of data during its transfer, i.e., before 

storage of the data with potential viruses on the destination storage medium.” 224 F.3d 

at 1350. 

2007-1201, -1239 10 
present on the destination storage medium and accessible by the operating system or 

other programs so that any viruses contained in the data can spread and infect the 

computer system.”5 Under these circumstances, the language in the preamble does not 

impose a separate claim limitation. 

B 

 Symantec also challenges the district court’s construction of the terms 

“computer” and “computer system.” The district court construed these terms to mean a 

“personal computer or workstation.” In doing so, the district court rejected Symantec’s 

proposed construction that “computer system” meant “any combination of hardware, 

software, documentation, and manual procedures that are combined to perform a 

specific function.” J.A. at 16. Based on the district court’s claim construction, the 

parties stipulated that the Gateway products do not infringe the asserted claims. 

The dispute here centers on whether the term “computer system” is properly 

limited to a single computer, or whether it covers a network of multiple computers. The 

district court explained that its construction limited the term “computer system” to a 

single personal computer or workstation. The district court premised its construction on 

the preferred embodiment’s use of a single computer, which as the court noted, 

“constitutes the complete description of the computer system.” The district court also 

relied on expert testimony that the term “computer system,” as used in the specification, 

referred to a single computer. 

 5

 Although implicit in the requirement that the screening is performed on 

“incoming digital data,” we note that the claims do not cover methods of screening data 

for viruses before that data has left the source storage medium. 

2007-1201, -1239 11 
On appeal, Symantec contends that the district court improperly limited the 

claims to cover only the preferred embodiment. The specification does not limit the 

invention to the preferred embodiment, and the ordinary meaning of the term “computer 

system,” according to Symantec, includes both a single computer and a system of 

multiple, interconnected computers. 

We agree with Symantec that the district court’s construction of the terms 

“computer” and “computer system” unduly limits the scope of the claims to a single 

personal computer. The claims “must be read in view of the specification, of which they 

are a part.” Phillips v. AWH Corp., 415 F.3d 1303, 1315 (Fed. Cir. 2005) (en banc). In 

Phillips, we characterized the specification as “the single best guide to the meaning of a 

disputed term.” Id. We find nothing in the specification that would limit the meaning of 

the term “computer” or “computer system” to a single computer. The terms are not 

expressly defined in the specification, and there is nothing in the specification that 

suggests that it adopted a special definition of those terms.6 Moreover, the expert 

testimony that the district court cites does not support the district court’s construction. 

That testimony simply recites how each expert would construe the term “computer 

system” based on his own reading of the specification. Such expert testimony, which 

does not identify the “accepted meaning in the field” to one skilled in the art, is 

unhelpful. Sinorgchem, 511 F.3d at 1137 n.3 (according little or no weight to expert 

testimony about the meaning of specification terms where the expert failed to present 

 6

 Although the preferred embodiment utilizes a single computer, this is not a 

case where the specification consistently refers to the invention as involving a single 

computer. See Ormco Corp. v. Align Tech., Inc., 498 F.3d 1307, 1313 (Fed. Cir. 2007). 

2007-1201, -1239 12 
evidence of the generally accepted meaning of those terms to persons of ordinary skill 

in the art). 

Because the specification does not reveal any special definition for the terms 

“computer” or “computer system,” we must construe those terms according to their 

ordinary meaning. In Phillips, we explained that “the words of a claim ‘are generally 

given their ordinary and customary meaning.’” 415 F.3d at 1312. We clarified that the 

relevant meaning 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.” Id. at 1313. Dictionaries are “among 

the many tools that can assist the court in determining the meaning of particular 

terminology to those of skill in the art of the invention.” Id. at 1318. Here, it is clear that 

the ordinary meaning of the terms “computer” or “computer system” as understood by a 

person of ordinary skill in the art at the time of the invention is not limited to a single 

computer or workstation. The Dictionary of Computing at that time defined the term 

“system,” in relevant part, as: 

Anything we choose to regard (a) as an entity and (b) as comprising a set 

of related components. In computing the word is widely used with many 

shades of meaning. Most commonly, however, it may refer to a related 

set of hardware units, or programs, or both. The hardware contents of a 

computer room may be spoken of as “the system,” and so may a range of 

manufacturer’s equipment[.] 

Dictionary of Computing 375 (2d ed. 1986). By contrast, the same dictionary defined 

the term “stand-alone” as “[d]enoting a computer system or subsystem that is capable of 

operation without being connected to any other computer system or subsystem.” Id. at 

360. In other words, a stand alone computer is only one type of computer or computer 

system. We therefore conclude that the ordinary meaning of the terms “computer” and 

“computer system” to one of ordinary skill in the art in 1990 was not limited to a single, 

2007-1201, -1239 13 
stand-alone computer or workstation and that the district court erred by unduly limiting 

its construction of those terms. 

Because we find that the terms “computer” and “computer system” are not limited 

to a single computer, we must vacate and remand to the district court on the issue of 

infringement of CA’s Gateway products. Given our construction of these terms, on 

remand, the district court should determine whether the combination of computers used 

in the Gateway system performs all the claimed method steps. 

C 

 Symantec also contends that the district court erred in construing the term 

“destination storage medium” to mean “a computer storage medium that is the target of 

the transfer of data as a result of the causing step.” This construction, when read 

together with the district court’s construction of the terms “computer” and “computer 

system,” which we rejected above, effectively limited the term “destination storage 

medium” to encompass only a storage system residing within a stand-alone computer, 

such as a computer’s hard drive. Such a limitation had the effect of excluding from the 

claim’s scope any peripheral devices, such as floppy drives or thumb drives. 

 The district court reasoned that construing “destination storage medium” to 

include peripheral devices would be inconsistent with its construction of the term 

“computer system,” since such a construction would “permit the invention to operate 

outside of the computer system.” J.A. at 18. Under the correct construction of 

“computer system,” there is no reason that “destination storage medium” must be 

limited to a computer hard drive. Under our construction of “destination storage 

medium,” peripheral devices, such as floppy drives and thumb drives, are properly 

2007-1201, -1239 14 
within the scope of that term. In addition, we note that the inclusion of peripheral 

devices within the scope of the term “destination storage medium” is consistent with the 

broad construction we gave that term in Hilgraeve II: “‘storage medium’ refers to any 

storage medium of the computer system, if the data, when stored on the medium, are 

accessible to the operating system or other programs, such that viruses in the data can 

spread and infect the computer system.” 265 F.3d at 1342 n.1. 

II 

 Next, Symantec argues that the district court improperly granted summary 

judgment of non-infringement on the EAV products based on a finding that CA does not 

induce infringement of the ‘776 patent. The district court held that the EAV products 

failed to meet both the “as it is being transferred” claim limitation and the “causing a 

quantity of digital data resident on a source storage medium to be transferred” claim 

limitation. As we have already found that the former was based on an erroneous claim 

construction, we now need only address the latter claim limitation. 

 Before the district court, there was no dispute that the EAV products do not 

“cause[] a quantity of digital data resident on a source storage medium to be 

transferred,” as required by claim 1. Instead, as the district court found, the EAV 

products work in conjunction with a downloading or copying program, such as an 

internet browser. The EAV products perform the anti-virus scanning; the downloading 

program performs the downloading. Symantec argued that CA induces its customers to 

infringe the ‘776 patent by promoting its EAV products to be used in an infringing 

manner in conjunction with a downloading program. The district court rejected this 

2007-1201, -1239 15 
argument. It held that Symantec could not establish active inducement because it did 

not show that any third party directly infringed the ‘776 patent using the EAV products. 

35 U.S.C. § 271(b) provides that “[w]hoever actively induces infringement of a 

patent shall be liable as an infringer.” “In order to succeed on a claim of inducement, 

the patentee must show, first that there has been direct infringement,” and “second, that 

the alleged infringer knowingly induced infringement and possessed specific intent to 

encourage another's infringement.” MEMC Elec. Materials, Inc. v. Mitsubishi Materials 

Silicon Corp., 420 F.3d 1369, 1378 (Fed. Cir. 2005) (quoting Minn. Mining & Mfg. Co. v. 

Chemque, Inc., 303 F.3d 1294, 1304-05 (Fed. Cir. 2002)). We recently clarified en 

banc that the specific intent necessary to induce infringement “requires more than just 

intent to cause the acts that produce direct infringement. . . . [T]he inducer must have an 

affirmative intent to cause direct infringement.” DSU Med. Corp. v. JMS Co., 471 F.3d 

1293, 1306 (Fed. Cir. 2006) relevant section (en banc). Thus, “inducement requires 

evidence of culpable conduct, directed to encouraging another's infringement, not 

merely that the inducer had knowledge of the direct infringer's activities.” Id. 

On appeal, Symantec asserts that it produced ample evidence to establish that 

the EAV products have no utility apart from screening downloaded or copied data files. 

That is, the EAV products operate only when a user downloads or copies a file onto his 

computer, and the downloading or copying must happen via a downloading or copying 

software program. In particular, Symantec points out that the EAV product manual 

establishes that CA promotes its use of the EAV product in combination with a 

downloading program in an infringing manner. The manual states that “[t]he Realtime 

Monitor scans programs on a workstation or server each time a file is executed, 

2007-1201, -1239 16 
accessed, or opened.” J.A. at 6213. In its discussion of the internet, the manual states 

that “[t]he newest source of infections is the Internet. . . . This feature works with 

browsers from Netscape and Microsoft.” Id. at 6214. In response, CA maintains that 

Symantec has not shown any evidence of direct infringement because it has not shown 

that any CA customer actually performs all of the claimed method steps. Absent such a 

showing, CA contends that the district court properly granted summary judgment. 

We find that there are genuine issues of material fact as to whether CA induced 

its customers to infringe the ‘776 patent. We agree with Symantec that CA encouraged 

customers to engage in direct infringement by using the EAV products in conjunction 

with a downloading program. This is not a case where the customers may be using the 

product in either an infringing way or a non-infringing way; CA’s customers can only use 

the EAV products in an infringing way. Under these circumstances, Symantec has 

produced sufficient circumstantial evidence of direct infringement to create a genuine 

issue of material fact, even though Symantec has not produced evidence that any 

particular customer has directly infringed the ‘776 patent. Direct evidence of 

infringement, as opposed to circumstantial evidence, is not necessary. See

Chiuminatta Concrete Concepts, Inc. v. Cardinal Indus., Inc., 145 F.3d 1303, 1312 (Fed. 

Cir. 1998) (finding that Cardinal's advertisements conceded the ability of the accused 

device to practice the claimed method, and encouraged such use); Moleculon Research 

Corp. v. CBS, Inc., 793 F.2d 1261, 1272 (Fed. Cir. 1986) (rejecting the argument that 

“proof of inducing infringement or direct infringement requires direct, as opposed to 

circumstantial evidence”). 

2007-1201, -1239 17 
We therefore vacate and remand the district court’s summary judgment finding of 

non-infringement with respect to the EAV products.7 On remand, the district court 

should consider whether the specific intent requirement set forth in DSU, which was 

decided after the grant of summary judgment in this case, was met. 

III 

On cross-appeal, CA challenges the district court’s summary judgment finding 

that the doctrine of laches does not bar Symantec’s recovery for CA’s alleged patent 

infringement prior to the filing of suit. At the outset, we dismiss CA’s laches claim as an 

improper cross-appeal. “A party may cross-appeal if adversely affected by the 

appealed judgment in some particular which it seeks to have modified.” TypeRight 

Keyboard Corp. v. Microsoft Corp., 374 F.3d 1151, 1156 (Fed. Cir. 2004) (internal 

quotation marks omitted). A cross-appeal may only be filed “when a party seeks to 

enlarge its own rights under the judgment or to lessen the rights of its adversary under 

the judgment.” Bailey v. Dart Container Corp., 292 F.3d 1360, 1362 (Fed. Cir. 2002). 

Thus, a properly filed cross-appeal requires that, upon acceptance of appellee’s 

argument, our determination would result in a reversal or modification of the judgment 

rather than an affirmance. See id. Here, the district court granted summary judgment 

of non-infringement on CA’s EAV products. CA argues on appeal that the doctrine of 

laches precludes Symantec from recovering damages on those products for any period 

before the filing of suit. Thus, even if we were to agree with CA that laches precludes 

Symantec’s recovery over the EAV products, our determination would have no effect on 

 

7

 We note that the district court appeared to confuse the test for inducement 

with the test for the doctrine of equivalents. The two concepts are not related. 

2007-1201, -1239 18 
the district court’s judgment. We therefore dismiss as improperly filed CA’s laches 

cross-appeal.8 

However, we may consider CA’s laches arguments as an alternative ground for 

sustaining the judgment of non-infringement. TypeRight Keyboard, 374 F.3d at 1160 

(“Even though we lack jurisdiction over the cross-appeal, [the appellee] may still defend 

the judgment on other grounds.”). We find that the district court did not err in dismissing 

CA’s laches defense on summary judgment. 

A defendant, in order to invoke the defense of laches, must prove: “(1) [that] the 

plaintiff delayed filing suit for an unreasonable and inexcusable length of time from the 

time the plaintiff knew or reasonably should have known of its claim against the 

defendant, and (2) [that] the delay operated to the prejudice or injury of the defendant.” 

A.C. Aukerman Co. v. R.L. Chaides Constr. Co., 960 F.2d 1020, 1032 (Fed. Cir. 1992) 

(en banc). A presumption of laches arises “upon proof that the patentee delayed filing 

suit for more than six years after actual or constructive knowledge of the defendant’s 

alleged infringing activity.” Id. at 1035-36. We review a district court's determination on 

the issue of laches for an abuse of discretion. Id. at 1039. 

 The ‘776 patent issued to Hilgraeve on June 7, 1994. In June 1995, an 

independent software company called Cheyenne Software began marketing a real-time 

antivirus software product called Inoculan. Hilgraeve sent a warning letter to Cheyenne 

dated October 5, 1996, regarding possible infringement. On November 6, 1996, CA 

 8

 CA’s other cross-appeals, directed to inequitable conduct, invalidity over 

the prior art, and inventorship, are proper because they would expand the scope of the 

judgment. In TypeRight Keyboard, we explained that “where the appellee urges 

invalidity as a new ground on which to support a judgment of non-infringement . . . a 

2007-1201, -1239 19 
acquired Cheyenne Software, and thereafter allegedly “re-branded” the Inoculan 

product into one of its eTrust antivirus products. Hilgraeve filed the present suit against 

CA on September 18, 2002, and, as discussed above, Symantec later acquired 

Hilgraeve’s interest in the ‘776 patent and was substituted as the plaintiff in the present 

suit. 

 Before the district court, CA argued that Symantec should be charged with the 

period of delay attributable to Hilgraeve when it stepped in as the plaintiff in the present 

suit. CA asserted that Cheyenne’s open and notorious marketing of Inoculan in June 

1995 established Hilgraeve’s constructive knowledge of Cheyenne’s infringing use, and 

that, regardless, the October 5, 1996, warning letter established Hilgraeve’s actual 

knowledge of Cheyenne’s infringing use. Finally, CA argued that by establishing 

Hilgraeve’s knowledge of Cheyenne’s alleged infringement, it was also establishing 

Hilgraeve’s knowledge with respect to the accused CA products at issue here, since CA 

“re-branded” the Inoculan product into one of its own. 

The district court held that Hilgraeve’s alleged knowledge of Inoculan, either 

constructive or actual, was insufficient as a matter of law to establish Hilgraeve’s 

knowledge of the alleged infringing CA products. In doing so, it did not reach the 

question of whether Symantec should be charged with Hilgraeve’s knowledge. Rather, 

it concluded that CA had failed to show evidence establishing that Inoculan was the 

same or similar to the products in suit. We agree that laches would only apply if the 

products were the same or similar, see Watkins v. Northwestern Ohio Tractor Pullers 

Association, Inc., 630 F.2d 1155, 1164 (6th Cir. 1980), and that CA has presented 

 

cross-appeal is necessary since a judgment of invalidity is broader than a judgment of 

2007-1201, -1239 20 
insufficient evidence that Inoculan is the same or similar to any of the products in suit.9

 

On appeal, CA does not point to any such evidence but contends that Symantec’s 

October 5, 1996, warning letter to CA, urging that it had committed willful infringement, 

must be interpreted as an admission that Inoculan was a precursor to one of the CA 

products at issue here. We cannot agree. Willful infringement requires an objective 

showing that the alleged actions constituted infringement of a valid patent, “determined 

by the record developed in the infringement proceeding.” In re Seagate Tech., LLC, 

497 F.3d 1360, 1371 (Fed. Cir. 2007). An allegation of willful infringement does not 

assume any similarity between Inoculan and the products in suit. We therefore find that 

the district court did not err in granting summary judgment to Symantec on CA’s laches 

defense. 

IV 

Levin (and CA) asserts that he is an omitted co-inventor of the ‘776 patent.10 To 

show co-inventorship, Levin is required to prove his contribution to the conception of the 

claims by clear and convincing evidence. See Ethicon, Inc. v. U.S. Surgical Corp., 135 

F.3d 1456, 1461 (Fed. Cir. 1998). An alleged co-inventor’s testimony, standing alone, 

cannot rise to the level of clear and convincing evidence; he must supply evidence to 

corroborate his testimony. Id. In Gemstar-TV Guide International, Inc. v. International 

Trade Commission, 383 F.3d 1352 (Fed. Cir. 2004), we explained that “[w]hether the 

 

non-infringement.” 374 F.3d at 1157 n.4. 

9

 Relying on an expert’s affidavit, CA asserts that the latest products at 

issue here utilize the same “antivirus engine technology” as that used in the original 

Inoculan product. This is hardly the same as demonstrating that the earlier product 

embodied the same claimed features as the accused product. 

10 Levin licensed any interest he may have in the ’776 patent to CA. 

2007-1201, -1239 21 
co-inventor's testimony has been sufficiently corroborated is evaluated under a ‘rule of 

reason analysis,’ which requires that an ‘evaluation of all pertinent evidence must be 

made so that a sound determination of the credibility of the inventor's story may be 

reached.’” Id. at 1382 (quoting Price v. Symsek, 988 F.2d 1187, 1195 (Fed. Cir. 1993)). 

Corroborating evidence may be in the form of “records made contemporaneously with 

the inventive process,” “[c]ircumstantial evidence of an independent nature,” or “oral 

testimony from someone other than the alleged inventor.” Id. 

 Before the district court, Levin submitted a declaration stating that he gave 

Matthew H. Gray (“Gray”), one of the named inventors of the ‘776 patent, the idea for 

the in-transit virus scan method in a February 12, 1990, telephone call. To corroborate 

his declaration, Levin submitted Gray’s day planner, which reflected Gray’s notes 

confirming that the disputed telephone call took place. Levin points out that Gray 

testified that the day planner entry that reflected his conversation with Levin was 

“relat[ed] to the ’776 patent.” J.A. at 10,064. In addition, Levin relied on the lack of 

evidence showing Gray’s conception of the in-transit virus scan invention, which he 

argued further corroborated his own testimony. 

The district court found that the day planner entry was insufficient as 

corroborating evidence. That entry, according to the district court, “at most shows only 

that [Levin and Gray] discussed the then-current state of the art”; it “fail[ed] to explicitly 

identify [Levin’s] contribution.” J.A. at 87-88. We agree with the district court that, at 

most, the day planner entry establishes that Gray and Levin spoke about the thencurrent state of anti-virus programs; it does not establish that Levin contributed to the 

idea. That entry, listing an “IBM SCAN program,” a “Computer Virus Handbook,” “Jim 

2007-1201, -1239 22 
McAffey’s Virus Scan,” and “Levin’s Checkup Antivirus System,” J.A. at 1841, suggests 

only that Gray simply called Levin to discuss the state of the prior art. 

The district court also found that any evidence tending to call into question Gray’s 

contribution to the invention was irrelevant to the question of whether Levin made any 

contribution. Again, we agree with the district court that the evidence regarding Gray’s 

contribution was not relevant to the question of Levin’s contribution. This is particularly 

so because Gray was not the sole inventor here; even though he may have lacked 

technical expertise, there is no suggestion that his co-inventors also lacked any 

technical expertise. This case is thus distinguishable from Ethicon, where we held that 

a sole inventor’s lack of technical expertise corroborated another’s claim of coinventorship. 135 F.3d at 1464-65. 

Levin’s declaration itself is insufficient because it lacks corroboration. We 

therefore affirm the district court’s conclusion that Levin has failed to establish a 

genuine issue of material fact that he was a co-inventor of the ’776 patent. 

V 

CA appeals the district court’s summary judgment determination that Hilgraeve 

did not commit inequitable conduct before the Patent Office in procuring the ’776 patent. 

CA alleges that Hilgraeve made three separate false and material misrepresentations to 

the Patent Office: (1) Gray’s April 18, 1990, declaration that he was an inventor of the 

’776 patent; (2) Gray’s August 12, 1990, declaration to overcome prior art; and (3) coinventor Donald Wakelin’s April 18, 1990, declaration that he understood the claims of 

the patent application. 

2007-1201, -1239 23 
Patent applicants “have a duty to prosecute patent applications in the Patent 

Office with candor, good faith, and honesty.” Honeywell Int’l Inc. v. Universal Avionics 

Sys. Corp., 488 F.3d 982, 999 (Fed. Cir. 2007). A breach of this duty constitutes 

inequitable conduct and renders the entire patent unenforceable. Id. In order to 

establish inequitable conduct, the party challenging the patent is required to establish by 

clear and convincing evidence that the patent applicant “(1) either made an affirmative 

misrepresentation of material fact, failed to disclose material information, or submitted 

false material information, and (2) intended to deceive the U.S. Patent and Trademark 

Office.” Cargill, Inc. v. Canbra Foods, Ltd., 476 F.3d 1359, 1363 (Fed. Cir. 2007). 

“Once threshold findings of materiality and intent are established, the trial court must 

weigh them to determine whether the equities warrant a conclusion that inequitable 

conduct occurred.” Purdue Pharma L.P. v. Endo Pharmaceuticals Inc., 438 F.3d 1123, 

1128 (Fed. Cir. 2006). 

Information is material when “a reasonable examiner would consider it important 

in deciding whether to allow the application to issue as a patent.” eSpeed, Inc. v. 

BrokerTec USA, L.L.C., 480 F.3d 1129, 1136 (Fed. Cir. 2007) (quoting A.B. Dick Co. v. 

Burroughs Corp., 798 F.2d 1392, 1397 (Fed. Cir. 1986)). Moreover, we have found that 

“[f]alse statements are more likely material when embodied in declarations or affidavits 

submitted to the PTO.” Id. 

CA’s first inequitable conduct claim arises out of the April 18, 1990, declaration 

that Gray signed and submitted with the patent application that led to the ‘776 patent. In 

the declaration, Gray submitted that he was “an original, first and joint inventor . . . of 

the subject matter which is claimed and for which a patent is sought.” J.A. at 1828-30. 

2007-1201, -1239 24 
CA asserts that Gray’s declaration was a false statement because the idea for the in 

transit virus-detection method was Levin’s. Even if Levin somehow contributed to the 

invention (which, as noted above, has not been established), that fact alone would not 

establish that Gray did not also contribute to the invention. CA also relies on Gray’s 

inability at trial to identify with specificity the contribution that he made to the invention. 

We agree with the district court that Gray’s inability to identify with precision his 

contribution, nearly fourteen years later, does not show anything more than that Gray 

simply could not recall, particularly since Gray and a co-inventor, John Hile, both 

testified in general terms that Gray came up with the idea.11 Finally, CA contends that 

Gray’s lack of technical expertise establishes that Gray was not an inventor. We 

disagree. Gray was not the sole inventor of the claimed method. Indeed, Gray worked 

with the other inventors who did have technical expertise to design the invention. For 

these reasons, we find that the district court did not err in granting summary judgment 

that CA has failed to present a genuine issue of material fact that Gray was not the 

inventor. 

 CA’s second inequitable conduct claim arises from an August 12, 1992, 

declaration submitted by Gray to the PTO in response to an office action. Gray’s 

declaration was submitted together with a number of prior art references. In the 

declaration, Gray described the state of the prior art with specific reference to the 

attached publications and identified the “significant advantages over the existing virus 

 11 CA appears to argue that Gray testified that the notes in the day planner 

described the invention, and that, since the notes summarized the Levin telephone call, 

the idea must have originated with Levin. Gray’s testimony, however, was that the day 

planner entry was evidence of the date of conception, and not of the idea itself. 

2007-1201, -1239 25 
scanning, detecting and eliminating software” that his invention achieved. J.A. at 3866. 

In paragraph 1 of the declaration, Gray stated that he “ha[d] practiced in the field of 

computer software and, more particularly, in the area of computer communications 

software for 10 years . . . [and that a]s a consequence, [Gray had] become intimately 

familiar with the state of the art as it relates to computer viruses, computer virus 

detection, and computer virus prevention.” Id. at 3863. CA claims that this declaration 

was false and misleading, because Gray was a marketing person, not a software 

person with technical expertise. 

 CA does not assert that the substance of the declaration itself was either false or 

misleading. The sole argument is that Gray’s description of his own qualifications is 

misleading. The district court found that Gray’s lack of technical expertise alone was 

insufficient to establish that his declaration was a misrepresentation. We agree. There 

is nothing in the record that indicates that Gray was not “intimately familiar with the state 

of the art,” and the mere fact that he was not a technical person does nothing to refute 

that.12

CA also relies on paragraph 4 of that declaration, where Gray stated that he “set 

out to develop an algorithm which would determine whether a file was infected with a 

virus during [a] transfer and to stop the transfer before the virus was copied into the 

system.” Id. at 3864. CA asserts that this claim was also false and misleading, since 

 12 When questioned as to whether “[s]itting here today, [Gray had] any 

knowledge concerning the state of the art in connection with computer software design 

and development,” Gray stated: “I don’t believe there’s any point in time when I would 

have been so bold as to claim I had knowledge of the state of the art of anything.” J.A. 

at 9993. We do not read that statement as contradicting the statement he made in the 

declaration concerning his earlier knowledge of virus screening technology, but rather to 

relate to his lack of knowledge of computer software design and development generally. 

2007-1201, -1239 26 
Gray later testified that he did not develop the mathematical algorithm, but rather that 

one of the co-inventors, Donald Wakelin, developed the algorithm. Gray’s assertion that 

he “set out to develop an algorithm” is not the same as asserting that he actually 

developed the algorithm himself. Again, we see no basis for a misrepresentation claim. 

We conclude that CA has not established a genuine question of material fact that Gray’s 

August 12, 1992, declaration was false or misleading. 

 CA’s final inequitable conduct claim arises from Wakelin’s April 18, 1990, 

declaration submitted with the original application, where he stated that he had 

“reviewed and underst[ood] the contents of the . . . specification, including the 

claims . . . .” Id. at 1828. That declaration, according to CA, was false and misleading 

because Wakelin allegedly did not understand the claims of the patent. Instead, 

Wakelin testified that he only understood the claims in general terms, that “the 

statements in claim one are so vague as to be practically unintelligible,” id. at 10006, 

and that he didn’t “really understand what these claims are saying.” Id. at 10007. The 

district court found that, even if Wakelin did not fully understand the claims of the patent, 

that alone was not sufficient to establish a threshold level of materiality. We agree. As 

the district court stated, “Wakelin’s failure to fully understand the language of the claim 

contents should not be confused for failure to understand the meaning of the claims, 

which would likely be considered material by a ‘reasonable examiner.’” Id. at 124. 

VI 

Finally, we must address CA’s counterclaims for invalidity. Our constructions of 

the terms “computer,” “computer system,” and “destination storage medium” require us 

to vacate and remand the district court’s summary judgment finding that the Photonix 

2007-1201, -1239 27 
and the Mac prior art references did not render the claims invalid. This is because the 

same construction governs for validity determinations as for infringement 

determinations. Yoon Ja Kim v. ConAgra Foods, Inc., 465 F.3d 1312, 1324 (Fed. Cir. 

2006). Here, the district court distinguished the ’776 patent claims over Photonix and 

the Mac prior art based on the conclusion that both of these antivirus programs ran on 

an Apple II GS computer, which itself only used peripheral devices (i.e., a floppy drive) 

because it did not include a hard drive.13 The district court also concluded, with respect 

to the invalidity of the claims based on the Mac prior art, that “the Macintosh programs 

do not store the actual screened digital data after screening, but only a reference to the 

screened data,” and therefore did not meet the claim limitation “automatically store the 

transferred digital data.” J.A. at 184-85. The district court’s decision in this respect is 

somewhat unclear as are the parties’ briefs on this point. The district court’s holding 

may well be intertwined with its holding that the Apple II GS computer, on which the 

Mac programs operated, did not have a destination storage medium. Under the 

circumstances, we decline to address the issue at this time. Hopefully the nature of the 

district court’s decision will be clarified on remand. 

CONCLUSION 

 We hold that the district court erred in its construction of the claim terms “a 

method of screening data as it is being transferred,” “destination storage medium,” 

“computer,” and “computer system.” We therefore vacate and remand as to noninfringement and invalidity. We affirm the district court’s decision on laches, inequitable 

conduct, and inventorship. 

 13 The district court appeared not to address claims 18-20, and on remand 

2007-1201, -1239 28 
2007-1201, -1239 29 

 

The judgment of the district court is AFFIRMED-IN-PART and VACATED-INPART and REMANDED. 

No costs. 

should treat them separately.