United States Court of Appeals for the Federal Circuit 

05-1018 

ENERGIZER HOLDINGS, INC. and 

EVEREADY BATTERY COMPANY, INC., 

Appellants, 

v. 

INTERNATIONAL TRADE COMMISSION, 

Appellee, 

and 

PT INTERNATIONAL CHEMICAL INDUSTRIAL CO. LTD., 

Intervenor, 

and 

GOLDEN POWER INDUSTRIES, LTD., 

GUANGDONG CHAOAN ZHENGLONG ENTERPRISE CO., LTD., 

GUANGZHOU TIGER HEAD BATTERY GROUP CO., LTD., 

FUJIAN NANPING NANFU BATTERY CO., LTD., 

HI-WATT BATTERY INDUSTRY CO., LTD., NINGBO BAOWANG BATTERY CO., LTD., 

SICHUAN CHANGHONG ELECTRIC CO., LTD., 

ZHEJIANG 3-TURN BATTERY CO., LTD., 

and ZHONGYIN (NINGBO) BATTERY CO., LTD., 

Intervenors. 

Randall G. Litton, Price, Heneveld, Cooper, DeWitt & Litton, LLP, of Grand Rapids, 

Michigan, argued for appellants. With him on the brief were Eugene J. Rath III and Matthew J. 

Gipson; Of counsel on the brief were V. James Adduci II and Maureen F. Browne, Adduci, 

Mastriani & Schaumberg, L.L.P., of Washington, DC. Of counsel were Michael L. Doane, 

David F. Nickel, Sarah E. Hamblin and S. Alex Lasher. 

Wayne W. Herrington, Attorney, Office of the General Counsel, United States 

International Trade Commission, of Washington, DC, argued for appellee. With him on the 

brief was James M. Lyons, General Counsel. Of counsel was Neal J. Reynolds, Attorney. 
-2- 

Kent R. Stevens, of Washington, DC, argued for intervenor PT International Chemical 

Industrial Co., Ltd. 

Steven P. Hollman, Hogan & Hartson L.L.P., of Washington, DC, argued for intervenors 

Golden Power Industries, Ltd., et al. With him on the brief were Christopher T. Handman, 

Susan M. Cook and Jessica L. Ellsworth; Of counsel on the brief were William E. Thomson, 

Jr., Wei-Ning Yang, Yoncha L. Kundupoglu and Olga Berson, of Los Angeles, California. Of 

counsel was Robert B. Wolinsky. 

Appealed from: United States International Trade Commission 
United States Court of Appeals for the Federal Circuit

 05-1018 

ENERGIZER HOLDINGS, INC. and 

EVEREADY BATTERY COMPANY, INC., 

Appellants, 

 v. 

INTERNATIONAL TRADE COMMISSION, 

Appellee, 

 and 

PT INTERNATIONAL CHEMICAL INDUSTRIAL CO. LTD., 

Intervenor, 

 and 

GOLDEN POWER INDUSTRIES, LTD., 

 GUANGDONG CHAOAN ZHENGLONG ENTERPRISE CO., LTD., 

GUANGZHOU TIGER HEAD BATTERY GROUP CO., LTD., 

FUJIAN NANPING NANFU BATTERY CO., LTD., 

HI-WATT BATTERY INDUSTRY CO., LTD., 

NINGBO BAOWANG BATTERY CO., LTD., 

SICHUAN CHANGHONG ELECTRIC CO., LTD., 

ZHEJIANG 3-TURN BATTERY CO., LTD., 

and ZHONGYIN (NINGBO) BATTERY CO., LTD., 

Intervenors. 

__________________________ 

DECIDED: January 25, 2006 

__________________________ 

Before NEWMAN, Circuit Judge, ARCHER, Senior Circuit Judge, and SCHALL, Circuit 

Judge. 

NEWMAN, Circuit Judge. 

Energizer Holdings, Inc. and Eveready Battery Company, Inc. (collectively "EBC") 

appeal the ruling of the International Trade Commission in an action under section 337 of 

the Tariff Act of 1930 as amended (19 U.S.C. §1337), holding all of the claims of EBC's 
05-1018 2

 

United States Patent No. 5,464,709 ("the '709 Patent") invalid for failure to comply with 35 

U.S.C. §112 ¶2.1

 We reverse the holding of invalidity and remand for further proceedings. 

The Invention

The '709 patent is for an electrolytic alkaline battery cell that is substantially free of 

mercury. Alkaline battery cells typically contain an electrolyte such as potassium 

hydroxide, a metal oxide cathode such as manganese dioxide, and a zinc anode. A 

detrimental characteristic of alkaline cells has been corrosion of the zinc after partial 

discharge, producing hydrogen gas which exerts internal pressure, causing the cell to leak. 

 A widely used corrosion inhibitor in such cells is mercury, which amalgamates with the zinc 

and inhibits hydrogen formation. Mercury, however, is an environmental pollutant, and 

extensive effort has been devoted to reducing or eliminating the mercury content in alkaline 

batteries. 

The '709 patent describes the discovery that a cause of gas-producing corrosion is 

the presence of trace impurities in the zinc used in the anode, and that upon identification 

and elimination of these impurities, the addition of mercury can be eliminated or 

substantially reduced. The electrolytic cells at issue are described as "zero-mercuryadded" batteries. EBC charged the respondents/Intervenors with violation of 19 U.S.C. 

§1337 based on their importation into the United States, sale for importation, and sale 

within the United States, of batteries asserted to infringe the '709 patent. 

1 In re Certain Zero-Mercury-Added Alkaline Batteries, Parts Thereof, and 

Products Containing Same, Inv. No. 337-TA-493 (Int'l Trade Comm'n, June 2, 2004 (Initial 

Determination); October 1, 2004 (Final Determination)). 
05-1018 3

In the Commission proceedings, the Administrative Law Judge construed the patent 

claims and held them valid and infringed. The Commission rejected the ALJ's claim 

construction and held all of the claims invalid for indefiniteness under 35 U.S.C. §112 ¶2, 

on the ground that the claim term "said zinc anode" lacks antecedent basis in the claim, 

and that the claims are unclear or ambiguous. EBC challenges this ruling, arguing that the 

meaning of "said zinc anode" and other usages in the claims, viewed in light of the 

specification, would be readily understood by persons of ordinary skill in the field of the 

invention, and that the absence of antecedent basis is not an invalidating flaw. 

Standard of Review 

We review the Commission's decision on the criteria established by 19 U.S.C. 

§1337(c) and the Administrative Procedure Act. In accordance with the APA, agency 

factual findings are sustained unless they are arbitrary, capricious, or unsupported by 

substantial evidence, and agency rulings of law are reviewed for correctness. 5 U.S.C. 

§706(2)(E). See Jazz Photo Corp. v. Int'l Trade Comm'n, 264 F.3d 1094, 1099 (Fed. Cir. 

2001) (applying the APA to review of decisions of the International Trade Commission). 

An analysis of claim indefiniteness under §112 ¶2 is "inextricably intertwined with 

claim construction." Atmel Corp. v. Information Storage Devices, Inc., 198 F.3d 1374, 1379 

(Fed. Cir. 1999). See Datamize v. Plumtree Software, Inc., 417 F.3d 1342, 1347-48 (Fed. 

Cir. 2005) ("'By finding claims indefinite only if reasonable efforts at claim construction 

prove futile, we accord respect to the statutory presumption of validity and we protect the 

inventive contribution of patentees, even when the drafting of their patents has been less 

than ideal.'") (quoting Exxon Research & Eng'g Co. v United States, 265 F.3d at 1371, 
05-1018 4

1375 (Fed Cir 2001)); Oakley, Inc. v. Sunglass Hut Int'l, 316 F.3d 1331, 1340-41 (Fed. Cir. 

2003) (determination of claim definiteness "requires a construction of the claims according 

to the familiar canons of claim construction"). Accordingly, we give de novo review to the 

Commission's ruling of patent invalidity for claim indefiniteness. 

35 U.S.C. §112 ¶2 requires that the patent specification shall "conclude with one or 

more claims particularly pointing out and distinctly claiming the subject matter which the 

applicant regards as his invention." This provision both facilitates examination during the 

patent application stage, and upon grant serves to notify the public of what is patented. 

The reviewing tribunal must determine whether a person experienced in the field of the 

invention would understand the scope of the claim when read in light of the specification. 

See Howmedica Osteonics Corp. v. Tranquil Prospects, Ltd., 401 F.3d 1367, 1371 (Fed. 

Cir. 2005) (claim not indefinite due to ambiguity when meaning readily ascertained from the 

description in the specification); Personalized Media Communications, LLC v. Int'l Trade 

Comm'n, 161 F.3d 696, 705 (Fed. Cir. 1998). See generally Phillips v. AWH Corp., 415 

F.3d 1303, 1313 (Fed. Cir. 2005) (en banc) (claims are construed in the context of the 

specification and prosecution history, as they would be understood by persons in the same 

field of endeavor). 

The Commission's Decision

The Commission held invalid independent claim 1 and dependent claims 2-7, for the 

claims all contain the usage to which the Commission objected. Claim 1 is as follows, with 

emphasis added to the term that was the focus of the Commission's decision: 

1. An electrochemical cell comprising an alkaline electrolyte, a cathode 

comprising manganese dioxide as an active cathode component, and an 
05-1018 5

anode gel comprised of zinc as the active anode component, wherein the cell 

contains less than 50 parts of mercury per million parts by weight of the cell 

and said zinc anode has a gel expansion of less than 25% after being 

discharged for 161 minutes to 15% depth of discharge at 2.88A. 

The Commission held the claim invalid because "said zinc anode" does not have an 

antecedent basis, the Commission explaining that "the term 'zinc anode' does not appear in 

the claim prior to the term 'said zinc anode.'" Final Det. at 22. The Commission also held 

that even if "said zinc anode" is construed to have as antecedent the "anode gel comprised 

of zinc as the active anode component" recited earlier in the claim, the claim would still be 

indefinite because, as written, it requires that the anode of every cell has been "discharged 

for 161 minutes to 15% depth of discharge at 2.88A." The Commission reasoned that since 

it appears that these discharge parameters are intended to apply only to a test cell, and not 

that every cell must be discharged, this unclear and ambiguous claim drafting renders the 

claim "indefinite as a matter of law." The Commission also held that EBC's proffer of 

alternative constructions of "said zinc anode" was an admission of indefiniteness. 

 DISCUSSION 

The Commission held the claim invalid because the term "said zinc anode" lacked 

an antecedent basis, and because of the claim's imprecise statement of the role of the test 

parameters. EBC argues that these flaws do not render the claim "insolubly ambiguous," in 

the words of Marley Mouldings, Ltd. v Mikron Industries, 417 F.3d 1356, 1361 (Fed. Cir. 

2005), which held that when a claim "is not insolubly ambiguous, it is not invalid for 

indefiniteness." See also Bancorp Servs., L.L.C. v Hartford Life Ins. Co., 359 F.3d 1367, 

1371 (Fed. Cir. 2004) ("We have held that a claim is not indefinite merely because it poses 
05-1018 6

a difficult issue of claim construction; if the claim is subject to construction, i.e., it is not 

insolubly ambiguous, it is not invalid for indefiniteness."). 

EBC argues that a person of ordinary skill in this field would readily understand the 

claim despite imperfect drafting, for the specification makes clear that the test parameters 

included in the claim do not mean that every cell must be discharged for 161 minutes. EBC 

points out that the '709 patent is directed to a standard electrolytic alkaline cell, and that the 

specification clearly states that the purpose of the test is to identify zinc anode material 

used in the invention. 

Claim definiteness is analyzed "not in a vacuum, but always in light of the teachings 

of the prior art and of the particular application disclosure as it would be interpreted by one 

possessing the ordinary level of skill in the pertinent art." In re Moore, 439 F.2d 1232, 1235 

(CCPA 1971). The definiteness inquiry "focuses on whether those skilled in the art would 

understand the scope of the claim when the claim is read in light of the rest of the 

specification." Union Pac. Res. Co. v. Chesapeake Energy Corp., 236 F.3d 684, 692 (Fed. 

Cir. 2001). Although neither the Commission nor the courts can rewrite claims to correct 

material errors, the issue here is not correction of error, but understanding of what the claim 

covers. When the meaning of the claim would reasonably be understood by persons of 

ordinary skill when read in light of the specification, the claim is not subject to invalidity 

upon departure from the protocol of "antecedent basis." 

The requirement of antecedent basis is a rule of patent drafting, administered during 

patent examination. The Manual of Patent Examining Procedure states that "[o]bviously, 

however, the failure to provide explicit antecedent basis for terms does not always render a 

claim indefinite." MPEP §2173.05(e) (8th ed. Rev. 2, May, 2004). In Slimfold 
05-1018 7

Manufacturing Co. v. Kinkead Industries, Inc., 810 F.2d 1113, 1117 (Fed. Cir. 1987) the 

court held that "the missing antecedent clause, the absence of which was not observed by 

the examiner of the original patent or by Kinkead in its reissue protest documents, did not 

fail to inform the public during the life of the ['274] patent of the limits of the monopoly 

asserted." The Slimfold court held that addition of the missing antecedent basis during 

reissue was not a substantive change. 

Whether this claim, despite lack of explicit antecedent basis for "said zinc anode," 

nonetheless has a reasonably ascertainable meaning must be decided in context. In 

prosecuting the '709 patent, the examiner made several objections to the claims, but the 

claims were not rejected or objected to on the ground of lack of antecedent basis. In Bose 

Corp. v. JBL, Inc., 274 F.3d 1354, 1359 (Fed. Cir. 2001) the court held that despite the 

absence of explicit antecedent basis, "If the scope of a claim would be reasonably 

ascertainable by those skilled in the art, then the claim is not indefinite." Moreover, we 

noted in Slimfold that an antecedent basis can be present by implication. Slimfold, 810 

F.2d at 1116. See Cross Medical Products v. Medtronic Sofamor Danek, 424 F.3d 1293, 

1319 (Fed. Cir. 2005). 

Neither the Commission nor the Intervenors argued that they did not understand the 

intended scope because of the absence of an antecedent. The Commission erred in 

holding that the need to construe a claim, or the proffer of alternative constructions, renders 

the claim indefinite. A claim that is amenable to construction is not invalid on the ground of 

indefiniteness. In Exxon Research & Engineering, 265 F.3d at 1375, the court stated that 

"if the meaning of the claim is discernible, even though the task may be formidable and the 

conclusion may be one over which reasonable persons will disagree, we have held the 
05-1018 8

claim sufficiently clear to avoid invalidity on indefiniteness grounds." See also Novo Indus., 

L.P. v. Micro Molds Corp., 350 F.3d 1348, 1353 (Fed. Cir. 2003) (determining whether 

claim is "amenable to construction"); Honeywell Int’l, Inc. v. Int'l Trade Comm'n, 341 F.3d 

1332, 1338 (Fed. Cir. 2003) (a claim is not indefinite because it is hard to construe). Here, 

it is apparent that the claim can be construed. In that regard, we conclude that "anode gel" 

is by implication the antecedent basis for "said zinc anode." The Commission's holding of 

invalidity on the ground of indefiniteness is reversed. 

No other issues of validity and infringement are before us on appeal. The case is 

remanded for further proceedings. 

REVERSED and REMANDED