Federal Circuit Rules on Internal Contradiction in Patent Application

The Federal Circuit has vacated an indefiniteness determination by a district court, distinguishing an indefinite patent claim with contradictory claim limitations from a patent claim having a second limitation that narrows the first limitation.

The case is Maxell v. Amperex.

As the court explains,

Maxell, Ltd. owns U.S. Patent No. 9,077,035, which describes and claims a rechargeable lithium-ion battery. Amperex Technology Limited is a manufacturer of lithium-ion batteries. In two now-consolidated actions, Maxell asserted infringement, and Amperex challenged the validity of claims of the ’035 patent. The ’035 patent’s claims require at least two lithium-containing transition metal oxides, represented by formulas that include a transition metal element M1, and, as relevant here, two limitations of the claims state requirements for that element. The district court held the claim language defining M1 to be indefinite on the ground that the two limitations contradicted each other…

Under 35 U.S.C. § 112, a 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.”

Patent claims that fail to meet the “particularly pointing out and distinctly claiming” requirement are invalid for indefiniteness. Also, when “claims, read in light of the specification delineating the patent, and the prosecution history, fail to inform, with reasonable certainty, those skilled in the art about the scope of the invention,” they are indefinite.

In this case, the district court based its indefiniteness conclusion on its determination that

the plain language of [claim 1] recites a contradiction” in that “[t]he first part of the claim recites a Markush group where [cobalt] is not necessarily required to be in the claimed compound while the second part of the claim recites that [cobalt] is necessarily required. For an element to simultaneously be optional and required is a contradiction on its face.

As the US Patent and Trademark Office (USPTO) explains, “A “Markush” claim recites a list of alternatively useable members” -- for example

at least one unit selected from the group consisting of (i) a dialysate-preparation unit, (ii) a dialysate-circulation unit, (iii) an ultrafiltrate-removal unit, and (iv) a dialysate-monitoring unit and a user/machine interface operably connected thereto…

A Markush grouping is proper if the members of a group share a single structural similarity and a common use.

According to the District Court, “For an element to simultaneously be optional and required is a contradiction on its face.”

The Federal Circuit disagreed, “not because a contradiction in a claim cannot produce indefiniteness,” but because “there is no contradiction in the claim language at issue in this case.”

Explained the court,

The first of the two limitations at issue regarding M1– limitation [c]—states one requirement a transition metal element must meet to come within the claim: It must contain cobalt, nickel, or manganese. The second limitation at issue—limitation [f]—states a second requirement: The transition metal element must contain cobalt at a content of 30% to 100% by mole. It is perfectly possible for a transition metal element to meet both requirements. The two limitations are, therefore, not contradictory.

Thus, the court reversed the ruling on indefiniteness and remanded the matter for further proceedings.