Addressing the issues of adequacy of notice under § 287(a) and application of doctrine of equivalents to claims having numerical ranges, the U.S. Court of Appeals for the Federal Circuit relaxed the strict requirement that § 287 notice be sent by the patent owner and held that a claimed recitation of a numerical range does not foreclose equivalents. U.S. Philips Corp. v. Iwasaki Elec. Co., Ltd., Case No. 07-1117 (Fed. Cir., Nov. 2, 2007) (Linn, J.).

The plaintiff, U.S. Philips, is the assignee of a patent claiming a high-pressure mercury vapor discharge lamps filled with a gaseous mixture in which "at least one of the halogens Cl, Br or I is present in a quantity between 10-6 and 10 -4 µmol/mm3." Mr. Rolfes, the patent portfolio manager of Philips International B.V., sent Iwasaki a letter on his Philips International B.V. letterhead. That stationery did not identify U.S. Philips as the patent owner and did not disclose the corporate relationship between U.S. Philips and Philips International B.V., an IP holding company. It did identify Mr. Rolfes as "Patent Portfolio Manager" speaking for "Corporate Intellectual Property, Philips International B.V." U.S. Philips later filed an infringement suit against Iwasaki alleging infringement of the patent and seeking damages back to the date of the notice letter.

The district court found that Rolfes' letter, though it identified "U.S. Philips Corporation, New York, N.Y.", as the patent assignee, did not constitute adequate notice for triggering damages as it did not come from the actual patent owner. The Federal Circuit reversed, noting that the information printed on the patent (attached to the letter) was enough to put an accused infringer on notice of the patent owner's identity, even though the assignment information printed on the face of a patent is not a conclusive indication of the patent's current ownership. Thus, the Court found the notice requirement, as explained by the Federal Circuit in Lans v. Digital Equipment, was satisfied since the patent owner was in fact identified, and the letter was sent as an invitation to contact B.V., the party having ultimate responsibility for licensing and enforcement of the patent.

On claim construction, the district court's construed the claim term, "a quantity between 10-6 and 10 -4 µmol/mm3," to be a range between, but not including either bound, i.e., 10-6 and 10 -4 µmol/mm3. Specifically the district court found that the range was not bounded by an order of magnitude or an approximation. The Federal Circuit affirmed, dismissing U.S. Philips' argument that a number such as 10 -4 means something different and less precise than 1 x10 -4.

However, the Federal Circuit reversed the district court's holding that infringement of the recited numerical range under the doctrine of equivalents would vitiate the claim limitation and that resort to the doctrine of equivalents was therefore foreclosed as a matter of law. Rather the Court found that the recitation of a numerical range does not preclude reliance or the doctrine of equivalents (distinguishing its holding in Moore v. Standard Register that the "qualitative" term "majority" could never encompass less than 50 percent) and remanded the matter to district court to consider, on a case-by-case basis and based on a Festo estoppel analysis, whether any of Iwasaki's lamps infringe under the doctrine equivalents.

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