Whether a "comprising" claim, in which the bottom side of a crate merges with the bottom edge of the crate's front wall, can encompass a crate in which the bottom side merges with the top AND bottom edges of the front wall, when the inventors, during reexamination, have overcome prior art (a crate wherein the bottom side merges with the TOP edge of the front wall) by limiting the reexamined claims to merger of the bottom side with the BOTTOM edge of the front wall.
No. The term "comprising" cannot be used in this manner as it would effectively change the scope of the claim, thereby regaining ground expressly given up to overcome prior art during reexamination.
Spectrum brought suit against Sterilite for alleged direct infringement and infringement under the doctrine of equivalents of Spectrum's U.S. Patent No. 4,971,202 "Stackable Recycling Crate" (the '202 patent). The '202 patent issued November 20, 1990, and again after reexamination on May 27, 1997. During reexamination, Spectrum overcame the examiner's prior art rejection based on the DePutter patent (U.S. Patent No. 3,682,351, disclosing a crate wherein the bottom side merged with the TOP edge of the front wall of the crate) by including the limitation that "the bottom side of the crate merge with at least a substantial portion of the bottom edge of the central portion of the crate's front wall." Spectrum, para. 5, referring to '202 patent at Col. 5, lines 24-26; Col. 6, lines 4-7. The commercial embodiment of Spectrum Corp. shows this configuration, whereas Sterilite's allegedly infringing crate has no commonly recognizable "central portion of the crate's front wall"; rather, this region is only as tall as the thickness of the crate material as provided by the bottom projecting to the front of the crate, thereby causing a merger of any "top" and "bottom" that there may be in the front wall. The lower court held that as a matter of law there was no literal infringement or infringement under the doctrine of equivalents on the ground that Sterilite's crate lacks a front wall altogether and therefore lacked all of the enumerated elements of the '202 patent claims at issue. The Federal Circuit upheld the District Court decision, but on different grounds.
On appeal, Spectrum argued that the claim term "comprising" permitted inclusion of the Sterilite product, because its claim could be interpreted to include a crate wherein the bottom side merged with the top edge AND the bottom edge of the central portion of the front wall of the crate. In constructing the claims as a matter of law, the Court stated that the "explicit statements made by a patent applicant during prosecution to distinguish a claimed invention over prior art may serve to narrow the scope of a claim." Spectrum, para. 18 (citation omitted). The Court then found that Spectrum's claims had been so narrowed during reexamination of the '202 patent when overcoming the DePutter patent. Quoting Moleculon Research Corp. v. CBS, Inc. 793 F.2d 1261, 1271, 229 USPQ 805, 812 (Fed. Cir. 1986), the court restated that "comprising . . . does not exclude unrecited elements," but may not be used to "alter the scope of the particular claim at issue." Spectrum, para. 22. Having interpreted the claims in this manner, the Court held as a matter of law that Sterilite neither literally infringed, because it lacked a recited element of the claims, nor infringed under the doctrine of equivalents due to prosecution history estoppel.