United States Court of Appeals for the Federal Circuit 

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LG ELECTRONICS, INC., 

Plaintiff-Appellant, 

v. 

BIZCOM ELECTRONICS, INC., 

COMPAL ELECTRONICS, INC., and SCEPTRE TECHNOLOGIES, INC., 

Defendants-Cross Appellants, 

and 

EVEREX SYSTEMS, INC., 

Defendant-Appellee, 

and 

FIRST INTERNATIONAL COMPUTER INC. 

and FIRST INTERNATIONAL COMPUTER OF AMERICA, INC., 

Defendants-Cross Appellants, 

and 

Q-LITY COMPUTER, INC., QUANTA COMPUTER, INC., 

and QUANTA COMPUTER USA, INC., 

Defendants-Cross Appellants. 

Richard G. Taranto, Farr & Taranto, of Washington, DC, argued for plaintiffappellant. On the brief was Michael J. Schaengold, Patton Boggs LLP, of Washington, 

DC. 

William J. Anthony, Jr., Orrick, Herrington & Sutcliffe LLP, of Menlo Park, 

California, argued for defendants-cross appellants Bizcom Electronics, Inc., et al. With 

him on the brief were Eric L. Wesenberg, Kaiwen Tseng, Matthew J. Hult and Rowena Y. 

Young. 
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Joseph L. Strabala, Law offices of Joseph L. Strabala, of San Francisco, California 

for defendant-appellee Everex Systems, Inc., joined in the co-defendants’ briefs. 

Ronald S. Lemieux, Paul, Hastings, Janofsky & Walker LLP, of Palo Alto, 

California for defendants-cross appellants First International Computer, Inc., et al. Of 

counsel on the brief was James M. Smith, Squire, Sanders & Dempsey L.L.P., of Palo 

Alto, California. 

Terry D. Garnett, Paul, Hastings, Janofsky & Walker LLP, of Los Angeles, 

California for defendants-cross appellants Q-Lity Computer, Inc., et al. With him on the 

brief were Vinent K. Yip, Maxwell A. Fox, Peter J. Wied, Sang N. Dang and Jay C. Chiu. 

Of counsel was Jeffrey D. Mills, Fulbright & Jaworski L.L.P., of Austin, Texas. 

Joel E. Lutzker, Schulte Roth & Zabel LLP, of New York, New York, for amicus 

curiae Minebea Co., Ltd. With him on the brief were David H. Kagan and Richard Chern. 

Steven E. Feldman, Welsh & Katz, Ltd., of Chicago, Illinois, for amicus curiae 

Papst Licensing GmbH & Co. KG. 

Appealed from: United States District Court for the Northern District of California 

Judge Claudia Wilken 
United States Court of Appeals for the Federal Circuit 

 

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LG ELECTRONICS, INC., 

 Plaintiff-Appellant, 

v. 

BIZCOM ELECTRONICS, INC., 

COMPAL ELECTRONICS, INC., and SCEPTRE TECHNOLOGIES, INC., 

Defendants-Cross Appellants, 

and 

EVEREX SYSTEMS, INC., 

Defendant-Appellee, 

and 

FIRST INTERNATIONAL COMPUTER INC. 

and FIRST INTERNATIONAL COMPUTER OF AMERICA, INC., 

Defendants-Cross Appellants, 

and 

Q-LITY COMPUTER, INC., QUANTA COMPUTER, INC., 

and QUANTA COMPUTER USA, INC., 

Defendants-Cross Appellants. 

 __________________________ 

 DECIDED: July 7, 2006 

 __________________________ 
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Before MICHEL, Chief Judge, NEWMAN, and MAYER, Circuit Judges. 

MAYER, Circuit Judge. 

 LG Electronics, Inc. (“LGE”) appeals from the final judgment of the United States 

District Court for the Northern District of California, which granted summary judgment of 

noninfringement of U.S. Patent Nos. 4,918,645; 5,077,733; 4,939,641; 5,379,379; and 

5,892,509 in favor of Bizcom Electronics, Inc.; Compal Electronics, Inc.; Sceptre 

Technologies, Inc.; First International Computer, Inc.; First International Computer of 

America, Inc.; Q-Lity Computer, Inc.; Quanta Computer, Inc.; Quanta Computer USA, 

Inc.; and Everex Systems, Inc. (collectively “defendants”). LG Elecs., Inc. v. Ausustek 

Computer, Inc., Nos. C-01-1375, -1552, -1594, -2187 (N.D. Cal. Jan. 31, 2005); LG 

Elecs., Inc. v. Ausustek Computer, Inc., Nos. C-01-1375, -1594, -2187, -1552 (N.D. Cal. 

Nov. 30, 2004); LG Elecs., Inc. v. Ausustek Computer, Inc., 248 F. Supp. 2d 912 (N.D. 

Cal. 2003); LG Elecs., Inc. v. Ausustek Computer, Inc., Nos. C-01-326, -1375, -1594, 

- 2187, -1552 (N.D. Cal. Aug. 20, 2002) (“Intel I”). LGE also appeals and defendants 

cross appeal various claim construction rulings by the trial court. LG Elecs., Inc. v. 

Ausustek Computer, Inc., Nos. C-01-00326, -01375, -01594, -02187, -01552 (N.D. Cal. 

Aug. 20, 2002) (“Claim Construction Order”). Defendants First International Computer, 

Inc.; First International Computer of America, Inc.; Q-Lity Computer, Inc.; Quanta 

Computer, Inc.; and Quanta Computer USA, Inc. also cross appeal the denial of 

summary judgment based on their implied license defense. LG Elecs., Inc., 248 F. 

Supp. 2d 912. 
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Background

LGE is the owner of patents relating to personal computers, including U.S. 

Patents Nos. 4,918,645 (disclosing systems and methods that increase the bandwidth 

efficiency of a computer’s system bus); 5,077,733 (claiming, in relevant part, a method 

that controls the access of a device to a bus shared by multiple devices); 4,939,641 

(claiming, in relevant part, a system for ensuring that outdated data is not retrieved from 

memory); 5,379,379 (claiming a system and method for ensuring that outdated data is 

not retrieved from memory); and 5,892,509 (claiming networked computers capable of 

sharing certain video images). LGE sued defendants alleging infringement of these 

patents. 

Defendants purchase microprocessors and chipsets from Intel or its authorized 

distributors and install them in computers. Intel is authorized to sell these products to 

defendants under an agreement with LGE. However, pursuant to this agreement, Intel 

notified defendants that, although it was licensed to sell the products to them, they were 

not authorized under that agreement to combine the products with non-Intel products. 

LGE brought suit against defendants, asserting that the combination of microprocessors 

or chipsets with other computer components infringes LGE’s patents covering those 

combinations. LGE did not assert patent rights in the microprocessors or chipsets 

themselves. 

After construing the patent claims, the trial court granted summary judgment of 

noninfringement of each patent. It determined that there was no implied license to any 

defendant, but that, with the exception of the ’509 patent, LGE’s rights in any system 

claims were exhausted. The court also found that LGE was contractually barred from 
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asserting infringement of the ’509 patent against defendants. It found the ’645, ’733, 

and ’379 patents not infringed after applying its claim construction to the accused 

methods and devices. We have jurisdiction under 28 U.S.C. § 1295(a)(1). 

Discussion

“We review the trial court's grant of summary judgment without deference, 

reapplying the same standard as the trial court.” Lacavera v. Dudas, 441 F.3d 1380 

(Fed. Cir. 2006) (citing Star Fruits S.N.C. v. United States, 393 F.3d 1277, 1281 (Fed. 

Cir. 2005)). Summary judgment is appropriate “if the pleadings, depositions, answers to 

interrogatories, and admissions on file, together with the affidavits, if any, show that 

there is no genuine issue as to any material fact and that the moving party is entitled to 

a judgment as a matter of law.” Fed. R. Civ. P. 56(c). We review claim construction de 

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

I. Implied License1

“In a suit for patent infringement, the burden of proving the establishment of an 

implied license falls upon the defendant.” Bandag, Inc. v. Al Bolser's Tire Stores, Inc., 

750 F.2d 903, 924 (Fed. Cir. 1984) (citing Bassick Mfg. Co. v. Adams Grease Gun 

Corp., 54 F.2d 285, 286 (2d Cir. 1931)). To prevail, defendants were required to 

establish that the products have no noninfringing uses and that “the circumstances of 

the sale . . . ‘plainly indicate that the grant of a license should be inferred.’” Met-Coil 

 1

 First International Computer, Inc.; First International Computer of America, 

Inc.; Q-Lity Computer, Inc.; Quanta Computer, Inc.; and Quanta Computer USA, 

Inc. are the defendants challenging the trial court’s implied license ruling. 
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Sys. Corp. v. Korners Unlimited, Inc., 803 F.2d 684, 686 (Fed. Cir. 1986) (quoting 

Bandag, Inc., 750 F.2d at 925). The trial court found, and we agree, that Intel’s sales of 

its licensed products to defendants do not warrant the inference of a license with 

respect to the asserted patents. Regardless of any noninfringing uses, Intel expressly 

informed them that Intel’s license agreement with LGE did not extend to any of 

defendants’ products made by combining an Intel product with non-Intel products. In 

light of this express disclaimer, no license can be implied. 

II. Patent Exhaustion

 The patents asserted by LGE do not cover the products licensed to or sold by 

Intel; they cover those products when combined with additional components. The trial 

court, nevertheless, found that the system claims in all patents except the ’509 patent 

were exhausted, but that the exhaustion doctrine did not apply to the method claims. 

We reverse the trial court’s holding with respect to the system claims and affirm with 

respect to the method claims. 

It is axiomatic that the patent exhaustion doctrine, commonly referred to as the 

first sale doctrine, is triggered by an unconditional sale. See Mitchell v. Hawley, 83 U.S. 

544, 547 (1873). “[A]n unconditional sale of a patented device exhausts the patentee's 

right to control the purchaser’s use of the device thereafter. The theory behind this rule 

is that in such a transaction, the patentee has bargained for, and received, an amount 

equal to the full value of the goods. This exhaustion doctrine, however, does not apply 

to an expressly conditional sale or license. In such a transaction, it is more reasonable 

to infer that the parties negotiated a price that reflects only the value of the ‘use’ rights 
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conferred by the patentee.” B. Braun Med. Inc. v. Abbott Labs., 124 F.3d 1419, 1426 

(Fed. Cir. 1997) (discussing Mallinckrodt, Inc. v. Medipart, Inc., 976 F.2d 700, 708 (Fed. 

Cir. 1992)) (emphasis added and citations omitted). 

There are two sales at issue here. First, prior to this litigation, LGE granted Intel 

a license covering its entire portfolio of patents on computer systems and components. 

This transaction constitutes a sale for exhaustion purposes. See United States v. 

Masonite Corp., 316 U.S. 265, 278 (1942). Second, with LGE’s authorization, Intel sold 

its microprocessors and chipsets to each defendant. Notably, this sale involved a 

component of the asserted patented invention, not the entire patented system. 

The trial court issued two orders on patent exhaustion. The first is unclear about 

which sale the court relied upon in holding LGE’s system patent rights exhausted with 

respect to defendants, but we understand it to be LGE’s license to Intel. Intel I at 9-10. 

However, the second order, which reaffirmed the first, clearly relied on Intel’s sale of its 

microprocessors and chipsets to defendants as the exhausting sale. LG Elecs., Inc., 

248 F. Supp. 2d at 917. In finding the unconditional sale requirement satisfied, the 

court concluded that although “LGE is entitled to impose conditions on the sale of the 

essential components of its patented products does not mean that it actually did so 

here. To the contrary, defendants’ purchase of the microprocessors and chipsets from 

Intel was unconditional, in that defendants’ purchase of the microprocessors and 

chipsets from Intel was in no way conditioned on their agreement not to combine the 

Intel microprocessors and chipsets with other non-Intel parts and then sell the resultant 

products.” Id. at 916-17. We disagree. 
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The LGE-Intel license expressly disclaims granting a license allowing computer 

system manufacturers to combine Intel’s licensed parts with other non-Intel 

components. Moreover, this conditional agreement required Intel to notify its customers 

of the limited scope of the license, which it did. Although Intel was free to sell its 

microprocessors and chipsets, those sales were conditional, and Intel’s customers were 

expressly prohibited from infringing LGE’s combination patents. Cf. N.Y. U.C.C. Law 

§ 2-202 (allowing contracts to be supplemented by consistent additional terms unless 

the writing is intended to be complete and exclusive). The “exhaustion doctrine . . . 

does not apply to an expressly conditional sale or license,” B. Braun Med. Inc., 124 F.3d 

at 1426, so LGE’s rights in asserting infringement of its system claims were not 

exhausted. 

 Conversely, the trial court declined to find LGE’s asserted method claims 

exhausted. Several defendants contest this ruling on cross-appeal, and we reject their 

challenge. Based on the above reasoning, even if the exhaustion doctrine were 

applicable to method claims, it would not apply here because there was no 

unconditional sale. However, the sale of a device does not exhaust a patentee’s rights 

in its method claims. Glass Equip. Dev., Inc. v. Besten, Inc., 174 F.3d 1337, 1341 n.1 

(Fed. Cir. 1999) (citing Bandag, Inc., 750 F.2d 903, 924 (Fed. Cir. 1984)). The court 

was correct. 

III. ’509 Patent

 The ’509 patent discloses a system of networked computers capable of sharing 

video images. The trial court’s exhaustion ruling did not extend to the ’509 patent; 
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instead it granted summary judgment of noninfringement on the ground that LGE was 

contractually barred from asserting infringement of the ‘509 patent claims against 

defendants. This conclusion was based on a non-assertion provision in a contract 

between LGE and Microsoft, which barred LGE from suing “[Microsoft], its suppliers, 

their subsidiaries, or their licensees.”2

 The court concluded that defendants were 

included within this class of parties. Because a genuine issue of material fact exists as 

to whether defendants fall within the protection of this contract provision, we reverse the 

trial court’s grant of summary judgment of noninfringement. 

In determining whether LGE is barred under the LGE-Microsoft agreement from 

suing defendants for infringement, the dispositive issue is whether each defendant is a 

Microsoft licensee. Defendants are third-party installers (“TPIs”) that assemble 

computers for original equipment manufacturers (“OEMs”). The OEMs have licenses 

with Microsoft, and it is undisputed that defendants were authorized to install Microsoft’s 

products on the systems they manufacture. It is unclear, however, whether defendants’ 

authorization was under “have made” rights of the OEMs’ agreements with Microsoft, 

whereby the OEM would be authorized to use a third party for completing work on its 

2 The relevant contract provision provides: 

{As partial consideration for the rights granted to 

[[LGE] under the License Agreement(s), [LGE] agrees 

not to (A) sue, or (B) bring, prosecute, assist or 

participate in any judicial, administrative or other 

proceedings of any kind against [Microsoft], its 

Suppliers, their subsidiaries, or their licensees 

(including without limitation [original equipment 

manufacturer] customers and end users) for 

infringement of [LGE’s] Patents . . . which occurs 

during the Immunity period . . . on account of the 

manufacture, use, sale, or distribution of . . . [the 

product’s licensed to LGE by Microsoft].}
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behalf, or whether such authorization was as a sublicensee. If the work was authorized 

solely by an OEM’s have made rights, and if that OEM were not authorized to grant 

sublicenses under its agreement with Microsoft, then defendants may not be “licensees” 

protected by the LGE-Microsoft non-assertion provision. Cf. Cyrix Corp. v. Intel Corp., 

77 F.3d 1381, 1388 (Fed. Cir. 1996) (distinguishing “have made rights” from 

sublicenses). A genuine issue of material fact exists as to each defendant’s status. 

On remand, defendants must establish that LGE is contractually barred from 

pursuing infringement claims against them. See McCoy v. Mitsuboshi Cutlery, Inc., 67 

F.3d 917, 920 (Fed. Cir. 1995). Although the parties have relied on the LGE-Microsoft 

agreement in arguing whether or not defendants are Microsoft licensees, that 

agreement is not the proper focus. It is the agreements between each OEM and each 

defendant, and those between Microsoft and the OEM hiring each defendant that 

matter. 

The record indicates that FIC was both a TPI and an OEM. As an OEM, it had a 

license from Microsoft, and therefore falls squarely within the scope of protected parties 

under the non-assertion provision. However, the contract provision only bars suit 

against Microsoft licensees for infringement “on account of” the manufacture, use, sale, 

or distribution of Microsoft’s products. LGE does not dispute that there is no 

infringement absent the Microsoft software in the accused devices, since the software 

satisfies some, but not all, limitations of the ’509 patent claims. However, LGE argues 

that any infringement was not “on account of” the use of Microsoft products. The trial 

court rejected this argument, essentially reading the “on account of language” as a “but 

for” requirement. 
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The “on account of” language, however, is not susceptible of only one 

interpretation. According to the Supreme Court in construing this phrase in an unrelated 

statute, “the phrase ‘on account of’ does not unambiguously define itself.” O’Gilvie v. 

United States, 519 U.S. 79, 82 (1996) (construing 26 U.S.C. § 7405(b)). Here, too, the 

degree of causation required by this contract term is unclear. Because proper 

construction requires factual considerations, we reverse the trial court’s grant of 

summary judgment. Scott Galvanizing, Inc. v. Nw. EnviroServices, Inc., 844 P.2d 428, 

433 (Wash. 1993); see also BNC Mortgage, Inc. v. Tax Pros, Inc., 46 P.3d 812, 819-820 

(Wash. Ct. App. 2002) (“If the contract's written words have two or more reasonable 

meanings (i.e., are ‘ambiguous’) when read in context, a court may not grant summary 

judgment or direct a verdict; instead, it must put the case to a trier of fact.”) (citations 

omitted). 

The parties also dispute the trial court’s construction of several claim terms in the 

’509 patent. Claim 35, from which asserted claims 45 and 51 depend, contains the 

limitation of “a control unit for controlling the communication unit, wherein the control 

unit comprises a [central processing unit (“CPU”)] and a partitioned memory system.” 

LGE contends that the trial court erroneously construed the term “control unit” as a 

means-plus-function limitation. 

“‘[A] claim term that does not use ‘means’ will trigger the rebuttable presumption 

that § 112 ¶ 6 does not apply.’” Lighting World, Inc. v. Birchwood Lighting, Inc., 382 

F.3d 1354, 1358 (Fed. Cir. 2004) (quoting CCS Fitness, Inc. v. Brunswick Corp., 288 

F.3d 1359, 1369 (Fed. Cir. 2002)). This presumption can be rebutted “by showing that 

the claim element recite[s] a function without reciting sufficient structure for performing 
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that function.” Watts v. XL Sys., 232 F.3d 877, 880 (Fed. Cir. 2000) (citing Rodime PLC 

v. Seagate Tech., Inc., 174 F.3d 1294, 1302 (Fed. Cir. 1999)). However, the 

presumption “is a strong one that is not readily overcome.” Lighting World, Inc., 382 

F.3d at 1358. 

Here, the claim limitation at issue does not use the term “means,” and the 

presumption against means-plus-function treatment is not overcome. The claim itself 

provides sufficient structure, namely “a CPU and a partitioned memory system,” for 

performing the stated function, “controlling the communication unit.” See id. at 1359-60. 

Thus, the proper construction of “control unit” is “a combination comprising a CPU and a 

partitioned memory system capable of controlling the communication unit.” 

 Defendants contend on cross appeal that the trial court also misconstrued claim 

35 by not requiring multiple displays. In particular, they contend that the preamble term 

“image processing system” requires multiple displays in light of the prosecution history. 

However, the claim language does not include this limitation, and the trial court properly 

refused to read it into the claim. Moreover, the body of the claim provides for “a 

display.” KCJ Corp. v. Kinetic Concepts, Inc., 223 F.3d 1351, 1356 (Fed. Cir. 2000) 

(“This court has repeatedly emphasized that an indefinite article ‘a’ or ‘an’ in patent 

parlance carries the meaning of ‘one or more’ in open-ended claims containing the 

transitional phrase ‘comprising.’”) (citations omitted). Claim differentiation also supports 

the trial court’s construction because dependent claim 38 adds the limitation of the 

“image processing system further compris[ing] at least first and second displays coupled 

to the CPU of the image processing system.” See Phillips v. AWH Corp., 415 F.3d 

1303, 1314 (Fed. Cir. 2005) (“Differences among claims can also be a useful guide in 
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understanding the meaning of particular claim terms.” (citing Laitram Corp. v. Rexnord, 

Inc., 939 F.2d 1533, 1538 (Fed. Cir. 1991))). 

The prosecution history relied upon by defendants does not compel a different 

construction. The patentee made arguments during prosecution to distinguish claims in 

the parent application to the ’509 patent, which expressly required multiple displays, 

over the prior art. These arguments, however, do not compel reading a multiple display 

limitation into the ’509 patent, which does not expressly require multiple displays. See

Elkay Mfg. Co. v. Ebco Mfg. Co., 192 F.3d 973, 980 (Fed. Cir. 1999) (“When multiple 

patents derive from the same initial application, the prosecution history regarding a 

claim limitation in any patent that has issued applies with equal force to subsequently 

issued patents that contain the same claim limitation.” (emphasis added)). 

 

IV. ’645 patent

The ’645 patent discloses a digital computer system that has devices called 

agents that are interconnected by a system bus. The claimed system and 

corresponding method require one agent, the requesting agent, to request access to a 

memory stored on another agent, called the replying agent. The requested data is 

organized as a matrix of memory cells, having column and row coordinates. The 

“memory controller” of the replying agent processes the request from the requesting 

agent by asserting a plurality of memory address control signals, including at least one 

row address strobe (“RAS”) signal and one column address strobe (“CAS”) signal. This 

“page mode memory access” operates by the assertion of an entire row of data followed 

by the assertion and deassertion of multiple column addresses. By the RAS signal 
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accessing an entire row followed by the assertion and deassertion of particular column 

addresses, this page mode memory access differs from the conventional memory 

access, which separately accessed each memory cell by asserting its individual row 

address and column address. In the claimed invention, after the data is accessed, it is 

then transferred to the requesting agent over the system bus. 

LGE alleged infringement of system claims 1-4 and 6 and method claims 12-15 

and 17. The trial court granted summary judgment of noninfringement of all asserted 

claims, concluding that the RAS/CAS signals in defendants’ devices did not travel over 

the system bus. However, the ’645 patent claims do not contain a limitation requiring 

that the strobe signals travel over the system bus. Moreover, the specification does not 

suggest that the strobe signals must travel over the system bus. To the contrary, Figure 

5 shows an embodiment of the invention in which the strobe signals travel only 

internally within the replying agent, not across the system bus. 

In an attempt to impose this limitation on the claims, defendants rely on the 

prosecution history. While the prosecution history is relevant to claim construction, “it 

often lacks the clarity of the specification and thus is less useful for claim construction 

purposes.” Phillips, 415 F.3d at 1317 (citations omitted). Here, defendants point to 

statements in the prosecution history that the prior art does not teach “a page mode 

type of access over a system bus from a requesting agent to a replying agent.” While 

we agree that this and other statements in the prosecution history lack ideal clarity, we 

do not find that they rise to the level of disclaiming or limiting the scope of the express 

claim language. Therefore, the trial court erred in construing the ’645 claims to require 

the RAS and CAS signals to travel over the system bus. In addition, there is a genuine 
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issue of material fact as to whether the accused devices and methods utilize strobe 

signals. LGE’s expert submitted an affidavit that the accused devices employ strobe 

signals, which precludes summary judgment. 

In the alternative, defendants contend that LGE failed to present evidence of an 

“end of access signal.” This signal, which is required by the claims, is generated by the 

requesting agent and received by a detecting means coupled to the memory address 

control signal asserting means. When the detection means receives this end of access 

signal, the operation is halted. Defendants contend that LGE failed to establish the 

existence of a genuine issue of material fact as to whether the accused devices contain 

this limitation. However, the trial court did not consider this argument, and we will not 

address this factual issue in the first instance. 

LGE also argues that the trial court’s construction of the “requesting agent” claim 

limitation was in error. The court construed this term as “a device coupled to the system 

bus that requests access to a memory located on a replying agent.” Claim Construction 

Order at 6-9. LGE contends that an industry standard, which was incorporated into the 

specification by reference, provides the proper claim construction of this term. ’645 

patent col. 3 ll. 51-56.3

 The incorporated standard explicitly defines the term 

 3

 The specification provides: 

Although the method and apparatus of the 

invention will be described herein in the context of a 

Multibus II environment, it should be appreciated that 

the invention may be practiced in many digital 

computer systems having a bus for transferring data 

between at least two agents interconnected upon the 

bus. 

The operating characteristics of the Multibus II 

are described in a document entitled “High 
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“requesting agent” as “an agent that has entered into the arbitration function for bus 

access.” Defendants contend, however, that the patentee did not act as its own 

lexicographer by incorporating this industry standard by reference. The trial court did 

not accept LGE’s proposed construction, concluding that it was a preferred embodiment 

and did not limit the claimed invention. The difference in the two constructions is 

temporal: LGE’s proposed construction defines an agent as a requesting agent only 

when it is engaged in arbitration for bus access, whereas the trial court’s construction 

defines a requesting agent regardless of whether it is actively engaged in arbitration. 

We have recognized that the “[i]nterpretation of descriptive statements in a 

patent's written description is a difficult task, as an inherent tension exists as to whether 

a statement is a clear lexicographic definition or a description of a preferred 

embodiment.” E-Pass Techs., Inc. v. 3COM Corp., 343 F.3d 1364, 1369 (Fed. Cir. 

2003). “Thus in determining whether a statement by a patentee was intended to be 

lexicographic, it is important to determine whether the statement was designed to define 

the claim term or to describe a preferred embodiment.” Id. We agree with the trial court 

and defendants that the patentee did not act as its own lexicographer here. Instead, the 

industry standard was incorporated as a preferred embodiment. The specification 

makes this clear by explaining that “[a]lthough the method and apparatus of the 

invention will be described herein in the context of a Multibus II environment, it should 

 

Performance 32-Bit Bus Standard P1296” which was 

produced by the IEEE microprocessor standards 

committee P1296 working group, Jun. 20, 1986, draft 

2.0, the disclosure of which is incorporated herein in 

its entirety. 

’645 patent col. 3 ll. 45-56.
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be appreciated that the invention may be practiced in many digital computer systems 

having a bus for transferring data between at least two agents interconnected upon the 

bus.” ’645 patent col. 3 ll. 45-49. 

Chimie v. PPG Industries, Inc., 402 F.3d 1371 (Fed. Cir. 2005), does not compel 

a different result. In Chimie, we were confronted with the claim terms “dust-free and 

non-dusting.” After concluding that these terms were relative and could only be 

understood by comparison with the prior art, we concluded that only one standard was 

disclosed in the specification for making such a comparison. We limited these claim 

terms to the disclosed standard. Here, however, there is no relative term that cannot be 

understood without reference to an industry standard. 

But, this does not end our inquiry. The proper claim construction is “the ordinary 

and customary meaning . . . that the term would have to a person of ordinary skill in the 

art in question at the time of the invention, i.e., as of the effective filing date of the patent 

application.” Phillips, 415 F.3d at 1313 (citations omitted). “When prior art that sheds 

light on the meaning of a term is cited by the patentee, it can have particular value as a 

guide to the proper construction of the term, because it may indicate not only the 

meaning of the term to persons skilled in the art, but also that the patentee intended to 

adopt that meaning.” Arthur A. Collins, Inc. v. N. Telecom Ltd., 216 F.3d 1042, 1045 

(Fed. Cir. 2000). Although we have concluded that the patentee did not expressly adopt 

the definition of “requesting agent” in the incorporated industry standard, that standard 

remains relevant in determining the meaning of the claim term to one of ordinary skill in 

the art at the time the patent application was filed, and it is treated as intrinsic evidence 

for claim construction purposes, see V-Formation, Inc. v. Benetton Group SpA, 401 
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F.3d 1307, 1311 (Fed. Cir. 2005) (“This court has established that ‘prior art cited in a 

patent or cited in the prosecution history of the patent constitutes intrinsic evidence.’”) 

(citations omitted). 

Here, the trial court erred by failing to give proper weight to the incorporated 

industry standard; it failed to consider the standard as intrinsic evidence of the meaning 

to one of ordinary skill in the art as of the filing date. After considering the standard, in 

addition to the patent claims and specification, we conclude that LGE’s proffered 

definition based on the standard is correct. Thus, we construe “requesting agent” as 

“an agent that has entered into the arbitration function for bus access.” This 

construction is entirely consistent with the specification, which provides that “at one time 

in the operation of the system . . . the requesting agent 12 may be a replying agent, and 

that the replying agent 16 may at that time be a requesting agent.” ’645 patent col.4 ll. 

8-11. This language makes clear that the classification of an agent depends upon the 

function the agent is performing at any given time, i.e., whether it is engaged in 

arbitration at a given moment. 

 

V. ’733 patent

The ’733 patent discloses a rotating priority system that provides multiple 

computer devices alternating access to a system bus, which is the pathway over which 

the various components of a computer system transmit data. This system addresses 

the problem of “hogging,” in which one component of a computer system monopolizes 
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access to the system bus. The asserted claims of the ’733 patent, method claims 15-

19,4

 establish a rotating priority system that limits each device’s access to the bus. In 

particular, claim 15 sets forth two steps of the method as “counting a number of 

accesses by the device to the bus” and then “in response to a predetermined number of 

accesses to the bus, giving another [device] the highest priority.” The trial court granted 

summary judgment of noninfringement of the ’733 patent, holding that the claim 

limitation of “counting a number of accesses by the device to the bus” was not practiced 

in the accused method. 

The court construed the claim limitation “counting a number of accesses” as 

“counting the number of times a device gains use of the bus.” Claim Construction Order

at 38-41. The parties do not directly challenge this construction, but LGE argues that a 

genuine issue of material fact exists as to whether the accused method performed this 

step. LGE argues that the master latency timer (“MLT”) in defendants’ accused devices 

performs this step. MLTs count clock signals when an anchor node has possession of 

 4

 Claim 15, the only independent claim at issue, provides: 

A method for determining priority of access to a bus among 

a set of devices coupled to the bus, each device being 

represented for priority purposes by a node in a group of 

nodes and each node having a priority relative to a single 

node currently having the highest priority, the method 

comprising the steps of: 

receiving an access request in a node from a 

represented device; 

determining whether any node with a higher priority 

has received an access request; 

if no such node has received an access request, 

permitting the device to access the bus; 

counting a number of accesses by the device to the 

bus; and 

in response to predetermined number of accesses to 

the bus, giving another node the highest priority. 
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the bus. Defendants contend that although an MLT limits the time duration of bus 

access by a device, it does not count the number of accesses by the device. 

Defendants also contend that, in some instances, the MLTs continue counting when 

clock signals pass even if no access to the bus is taking place, such as during WAIT 

periods when no data is being placed on the bus. 

LGE responds that the bus is accessed even during WAIT periods, regardless of 

whether any data is placed on the bus, because the device has access to the bus. LGE 

points out that the purpose of the invention is to eliminate “hogging” the bus, and that 

the bus is “being hogged” even during WAIT periods. Further, LGE argues that, under 

the trial court’s construction, a device still has “use of the bus” during a wait period. 

LGE points to the discussion in the ’733 patent relating to Figure 8. ’733 patent col. 21. 

In this preferred embodiment, the description includes a programmable node grant 

counter NGCNT 720. The description explains that when certain conditions are met, an 

enable count input is asserted and during a bus access cycle a transition of a clock 

signal causes NGCNT 720(1) to increment by one count. Therefore, when certain 

criteria are met, a clock signal can create an access count. 

There is a genuine issue of material fact as to whether the accused devices 

count the number of accesses. See Ranbaxy Pharms., Inc. v. Apotex, Inc., 350 F.3d 

1235, 1240 (Fed. Cir. 2003) (“Infringement, both literal and under the doctrine of 

equivalents, is a question of fact.” (citing Insituform Techs., Inc. v. Cat Contracting, Inc., 

161 F.3d 688, 692 (Fed. Cir. 1998))). The central issue is whether the bus is accessed 

on each clock signal so that the clock signals, in effect, count the number of accesses to 

the bus. The trial court agreed that LGE’s argument is consistent with its claim 
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construction, but found that it failed to present evidence supporting its position. To the 

contrary LGE presented sufficient expert testimony on this issue to avoid summary 

judgment. LGE’s expert testified that some type of signal is asserted with each clock 

signal, and, if proven, this would in effect make the MLTs count accesses. The 

summary judgment is vacated. 

VI. ’641 patent

The ’641 patent discloses a system for ensuring that the most current data is 

retrieved from the main memory. Because individual devices can update data in their 

own local cache memory without immediately writing the new data back to the main 

memory, data in the main memory can be “stale.” Therefore, the system claimed in the 

’641 patent monitors the data being transferred over the bus, and if data stored in the 

cache matches the address of the data being transferred, a hold signal is asserted. 

Then, the data being transferred is compared with the data on the cache. If there is a 

difference, the data stored on the cache, which is the most recent data, is also 

transferred. 

The trial court concluded the ’641 patent claims asserted were not infringed 

based on its patent exhaustion holding, which we reverse above. However, LGE 

contends that the trial court also improperly construed claims 1, 5, and 14. In particular, 

LGE disputes the trial court’s construction of “cache memory means” (in claims 1 and 5) 

and “cache memory” (in claim 14), which were construed as “one of at least two high 

speed memories located close to the CPU of a computer to give the CPU faster access 

to blocks of data than could be taken directly from the larger, slower main memory and 
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never using valid/invalid bits.” Claim Construction Order at 18-22. LGE contends that 

the trial court improperly read claims 1 and 14 as requiring at least two caches. It also 

contends that the trial court improperly read in the limitation that neither cache uses 

valid/invalid bits. 

We agree with LGE that the trial court erred in reading the limitation of at least 

two high speed memories into claims 1 and 14. Unlike claim 5, which expressly 

requires at least two cache memory means, claims 1 and 14 have no such express 

limitation. Cf. Phillips, 415 F.3d at 1314 (“Differences among claims can also be a 

useful guide in understanding the meaning of particular claim terms.” (citing Laitram 

Corp. v. Rexnord, Inc., 939 F.2d 1533, 1538 (Fed. Cir. 1991))). To the contrary, claims 

1 and 14 only require one or more CPUs and a cache memory coupled between the 

CPU and the bus. Because the claims expressly cover one central processing unit, 

they logically also cover systems with only one cache coupled between that single 

central processing unit and the bus. Defendants rely on the fact that the written 

description describes a system with multiple caches. However, as we explain in more 

detail below, the patent application initially described two inventions, and these 

statements relate to the other invention that is not claimed in the ’641 patent. 

 We also agree with LGE that the trial court improperly read the limitation of never 

using valid/invalid bits into the claims. The patent’s background section suggests that 

valid/invalid bits were used to manage data in systems with more than one cache. In 

particular, it explains that the purpose of the invalid bit is to redirect a processor 

attempting to access an address in its cache to another cache with a more updated 

memory associated with that address. ’641 patent col. 1 ll. 44-52. The claims at issue 
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do not themselves expressly include or exclude the use of valid/invalid bits. 

Defendants, however, contend that the trial court’s construction is supported by the 

specification and prosecution history. The specification states that “a further object of 

this invention [is] to provide a cache memory system wherein the use of valid/invalid 

data indicators are avoided.” ’641 patent col. 1 ll. 65-67. It further states that “[i]t should 

be kept in mind during the following description, that the invention maintains data 

integrity by assuring that cache data is always the most up-to-date in the system. Thus, 

there never is a ‘valid’ or ‘invalid’ indication with respect to any cache data as it is 

always assured that if data is provided by a cache, that it invariably is valid (i.e. most 

up-to-date).” Id. col. 3 ll. 27-33. 

Defendants are correct that reviewing the specification in construing claims is 

appropriate, Phillips, 415 F.3d at 1315-17, but such review need not be done in the 

abstract. Here, as noted above, the original patent application disclosed two inventions. 

As the examiner observed, one invention was “drawn to a cache system for updating 

each copy of the data stored in a plurality of caches when the data is modified,” and the 

other was drawn to “a cache system for sending the most current data to a requestor by 

monitoring the address of a data on a data bus for detecting whether the [data] is stored 

and modified in the cache.” The patent examiner concluded that these two inventions 

were distinct and required the applicant to elect one invention. The applicant ultimately 

limited the original application to the latter group of claims, which issued as the ’641 

patent, and the other claim group was separated into a different application, which 

ultimately issued as U.S. Patent No. 5,097,409. 
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Here, the discussion of valid/invalid bits in the specification was relevant to multicache systems, because the patent’s background provides that “[s]o long as a write 

back cache is utilized with only one processor, data management is straight forward. 

However, when more than one central processor uses the same main memory, data 

management problems multiply.” ’641 patent col. 1 ll. 39-43. The patent explains that 

the data management problems in multiple CPU systems are a result, at least in part, of 

their containing more than one cache memory. Managing data in multiple cache 

systems was the subject of the invention not elected during prosecution and, therefore, 

the statements in the specification referring to valid/invalid bits are not relevant to the 

invention ultimately claimed in the ’641 patent. Cf. Pitney Bowes, Inc. v. HewlettPackard Co., 182 F.3d 1298, 1311 (Fed. Cir. 1999) (observing that a written description 

describing multiple inventions may not be relevant “in toto” to each of those inventions). 

Indeed, the unelected claims expressly contained the limitation that the “cache memory 

means hav[e] no provisions for indicating the invalidity of said data units,” whereas the 

elected claims contained no such limitation. 

For the same reasons, we do not find that the patentee disavowed the use of 

valid/invalid bits under the doctrine of specification disclaimer. “[T]he specification may 

reveal an intentional disclaimer, or disavowal, of claim scope by an inventor. In that 

instance, . . . the inventor has dictated the correct claim scope, and the inventor’s 

intention, as expressed in the specification, is regarded as dispositive.” Phillips, at 

1316; see also SciMed Life Sys. v. Advanced Cardiovascular Sys., 242 F.3d 1337, 1341 

(Fed. Cir. 2001). However, because the statements relied upon by defendants relate to 
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the invention not elected during prosecution, there is no clear disavowal with respect to 

the invention actually claimed in the ’641 patent. 

VII. ’379 patent

Like the ’641 patent, the ’379 patent claims a system and method for ensuring 

that the most current data, as opposed to “stale” data, is retrieved from memory. The 

claimed invention relates to how a memory controller coordinates requests to read data 

from the memory and requests to write data to the memory. Generally, when a read 

request is asserted that corresponds to a buffered write request, the write request must 

go first to ensure that what is read from memory is the most current data. The invention 

disclosed in the ’379 patent does this by comparing the address of each read request to 

the buffered write requests, noting any matches, halting read execution when there is a 

match, and executing the buffered write requests. 

LGE contends that the trial court erred in construing system claims 1 and 23 as 

requiring all write requests to be executed after a match is detected, as opposed to 

executing any number of write requests until the write request corresponding to the 

matching read request is executed. We agree. The claim language does not require all 

write requests to be executed after a match is detected. Moreover, claim 2, which 

depends from claim 1, expressly requires the execution of all write requests, as does 

independent method claim 7. See Phillips, 415 F.3d at 1314 (recognizing the utility of 

claim differentiation). In addition, the claim limitation at issue is written in means-plus 

function-claim language (“means for . . . causing an execution of buffered write 

requests”). Because the recited function is clear on its face, it was improper to 
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incorporate the additional functional limitation of executing “all” buffered write requests. 

Smiths Indus. Med. Sys., Inc. v. Vital Signs, Inc., 183 F.3d 1347, 1357 (Fed. Cir. 1999); 

see also Wenger Mfg., Inc. v. Coating Mach. Sys., Inc., 239 F.3d 1225, 1233 (Fed. Cir. 

2001) (“[A] court may not import functional limitations that are not recited in the claim 

. . . .”). 

LGE also disputes the trial court’s grant of summary judgment of noninfringment 

of method claim 7.5 This claim explicitly requires the step of buffering “each” read 

 5

 Claim 7 provides: 

In an information processing system having a system bus for 

coupling together a plurality of bus connections, one of the 

bus connections being a memory control unit coupled to one 

or more memory units, the memory control unit being 

responsive to address and data signal lines of the system 

bus for writing information units to and for reading 

information units from the memory units, a method of 

reading and writing the information units comprising the 

steps of: 

buffering write requests, including write addresses, as 

they are received from the system bus; 

buffering read requests, including read addresses, as 

they are received from the system bus; comparing 

when received each read address against buffered 

write addresses, if any, to determine if a received 

read address has an address value within a 

predetermined range of address values of a buffered 

write address; 

if a received address is determined not to be within 

the predetermined range of addresses of any buffered 

write addresses then: 

first executing in sequence all buffered read 

requests; and then executing in sequence all 

buffered write requests; 

else if a received address is determined to have an 

address value within the predetermined range of 

address values of any buffered write address: 

first executing in sequence all buffered read requests 

up to but not including the received read request 
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request and then comparing that read request to the buffered write addresses. If the 

read request matches a write request, then the claim provides for the following steps: 

executing all buffered read requests up to the matching request; then executing “all 

buffered write requests;” and then executing the matching read request. If, however, 

the comparison of the read request does not yield a match to a buffered write request, 

then all read requests are executed. Defendants contend, and LGE does not appear to 

dispute, that the accused devices do not operate in this manner. Instead, they contend 

that when a buffered read request matches a buffered write request, their devices do 

not execute “all” write requests before executing the matching read request, but instead 

only execute the write requests up to the one matching the read request, and then 

execute the matching read request. 

The trial court concluded, and we agree, that there was no literal infringement of 

this claim. The claimed method requires handling each read address in one of two 

ways depending on whether the read request matches a write request. The second 

way, which applies when the pending read request matches a pending write request, is 

to execute all write requests before executing the read request. LGE contends that 

when the matching write request happens to be the last in the buffer, all write requests 

are in fact executed before the matching read request. Although LGE correctly asserts 

that any practice of the claimed method would be infringement, Bell Commc’ns 

Research, Inc. v. Vitalink Commc’ns Corp., 55 F.3d 615, 622 (Fed. Cir. 1995), the claim 

 

which was determined to be within the predetermined 

range; 

then executing all buffered write requests; and 

then executing the buffered read request which 

was determined to be within the predetermined range. 
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must be considered in its entirety. Here, the claim requires each read request to be 

compared with the buffered write requests, and then one of two alternatives be followed. 

Because the claim was drafted with this limitation, the fact that the accused device 

occasionally operates in such a manner does not amount to literal infringement of claim 

7. For infringement to be found, the claim requires the accused device to operate in this 

manner in response to “each” read request. 

The trial court also found, as a matter of law, that there was no infringement 

under the doctrine of equivalents. In doing so, it rejected LGE’s argument that 

performing all of the write requests up to (and including) the one matching the read 

request is an insubstantial difference from the claim limitation of performing all write 

requests before executing the incoming read request. The trial court reasoned that 

LGE’s equivalence theory would vitiate the claim limitation of performing “all” write 

requests before an incoming read request matching a write request. 

The doctrine of equivalents operates under the “all limitations rule,” whereby 

“equivalence [is] assessed on a limitation-by-limitation basis, as opposed to from the 

perspective of the invention as a whole.” Freedman Seating Co. v. Am. Seating Co., 

420 F.3d 1350, 1358 (Fed. Cir. 2005) (citing Warner-Jenkinson Co. v. Hilton Davis 

Chem. Co., 520 U.S. 17, 29 (1997)). This doctrine, by its very nature, extends beyond 

the patent’s literal claim scope, because otherwise a finding of no literal infringement 

would be a foreordained conclusion of no infringement at all. Ethicon Endo-Surgery v. 

U.S. Surgical Corp., 149 F.3d 1309, 1317 (Fed. Cir. 1998). At the same time, however, 

“[i]f our case law on the doctrine of equivalents makes anything clear, it is that all claim 
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limitations are not entitled to an equal scope of equivalents.” Moore U.S.A., Inc. v. 

Standard Register Co., 229 F.3d 1091, 1106 (Fed. Cir. 2000). 

“There is no set formula for determining whether a finding of equivalence would 

vitiate a claim limitation, and thereby violate the all limitations rule. Rather, courts must 

consider the totality of the circumstances of each case and determine whether the 

alleged equivalent can be fairly characterized as an insubstantial change from the 

claimed subject matter without rendering the pertinent limitation meaningless.” 

Freedman Seating Co., 420 F.3d at 1359 (citations omitted). LGE contends that 

performing some of the write requests is a permissible equivalent to performing all write 

requests, and that while performing no write requests may vitiate the claim language, 

performing some does not. As discussed above, there is inevitably a range of 

equivalents for performing all write requests, even if that range is narrow. See Ethicon 

Endo-Surgery, 149 F.3d at 1317. If substantially all or nearly all write requests are 

performed by the accused devices before each matching read request, then the 

doctrine of equivalents would be fully applicable without vitiating the claim language. 

Although such scope would be outside of the claim’s literal scope, which is true in any 

doctrine of equivalents analysis, it would not be inconsistent with the language of the 

claim. Therefore, a genuine issue of material fact exists as to whether the accused 

device can function within the narrow range of equivalents that we have described 

above, and we vacate the trial court’s grant of summary judgment of noninfringement on 

this ground. 
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Conclusion

 Accordingly, the judgment of the United States District Court for the Northern 

District of California is affirmed in-part, reversed in-part, and vacated in-part. The case 

is remanded for further proceedings in accordance with this opinion. 

COSTS 

 LGE shall have its costs. 

AFFIRMED-IN-PART, REVERSED-IN-PART, VACATED-IN-PART, AND REMANDED