Federal Circuit Finds Lack Of Antecedent Basis Does Not Automatically Render Claim Indefinite Without Evidence Of Confusion As To Claim Scope

In Energizer Holdings, Inc. v. International Trade Commission, Energizer Holdings brought an action under 19 U.S.C. §1337 to prevent the importation of alkaline battery cells which Energizer asserted infringed claim 1 of Energizer’s U.S. Patent No. 5,464,709.  Claim 1 recites as follows:

1. An electrochemical cell comprising an alkaline electrolyte, a cathode comprising manganese dioxide as an active cathode component, and an 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.

After the proceedings, the Administrative Law Judge initially found that claim 1 was valid and infringed by the importation.  However, the International Trade Commission overruled the Administrative Law Judge and found claim 1 invalid under 35 U.S.C. §112, paragraph 2, for being indefinite to the since claim 1 did not previously recite an zinc anode prior to reciting “said” zinc anode.  

On appeal, the Federal Circuit reviewed the International Trade Commission’s finding of invalidity de novo since the issue is strongly intertwined with claim construction.  The Federal Circuit also noted that, while the lack of antecedent basis can cause indefiniteness, invalidity based upon indefiniteness must be based on the totality of the claim as read in the context of the specification by one skilled in the art.  According to the Federal Circuit, “[w]hen 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.'” As such, the Federal Circuit held that the requirement of antecedent basis is “a rule of patent drafting, administered during patent examination,” and is not an automatic grounds for invalidity.

Based upon this test, the Federal Circuit that there is no evidence that the scope of the claim was not understood by one of ordinary skill in the art, and that “the Commission nor the Intervenors argued that they did not understand the intended scope because of the absence of an antecedent.”  Further, the Federal Circuit noted that the Examiner, during prosecution, made several other rejections but also did not make a rejection regarding a lack of antecedent basis, which evidenced that the scope of the claim was understandable and definite.  Thus, the Federal Circuit held that the International Trade Commission erred in finding claim 1 invalid under 35 U.S.C. §112, and reversed and remanded the case for further proceedings. 

A copy of the case can be found at Energizer Holdings, Inc. v. International Trade Commission, 435 F.3d 1366; 77 U.S.P.Q.2D 1625 (Fed. Cir. 2006).


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