No Infringement by Equivalents Where Specification Criticized Prior Art Attachment Means
September 12, 2007
Last Month at the Federal Circuit - October 2007
Judges: Newman, Rader, Dyk (author)
[Appealed from: W.D.N.C., Judge Conrad]
In L.B. Plastics, Inc. v. Amerimax Home Products, Inc., No. 06-1465 (Fed. Cir. Sept. 12, 2007), the Federal Circuit affirmed the district court’s claim construction and grant of SJ of noninfringement.
U.S. Patent No. 6,463,700 (“the ’700 patent”) relates to gutter guards, which can be attached to a conventional gutter in order to filter out dirt, leaves, and other debris from the flow of water. During prosecution, independent claim 1 was amended to recite a gutter guard comprising, among other elements, “a continuous heat weld defining an uninterrupted longitudinal weld line.” Claim 1 is representative of the other two independent claims, which both require that the guard panel be welded to the mesh layer and that the resulting “weld line” be “continuous.” The specification of the ’700 patent criticizes prior art attachment means, stating that “[t]he attachment means used in other prior art gutter guards incorporating multiple layers is generally less effective, and more costly, time consuming, and labor intensive.”
L.B. Plastics, Inc. (“L.B. Plastics”) sued Amerimax Home Products, Inc. (“Amerimax”), alleging that Amerimax’s competing gutter guard infringed the ’700 patent. L.B. Plastics argued that Amerimax’s gutter guards literally infringed the ’700 patent because the “continuous heat weld” limitation of the patent was broad enough to encompass the hot glue adhesive used by Amerimax. Alternatively, L.B. Plastics claimed that the “continuous heat weld” limitation of the ’700 patent and Amerimax’s hot glue adhesive were equivalent.
The district court granted Amerimax’s motion for SJ of noninfringement. Regarding literal infringement, the district court determined that the Amerimax products did not involve a “heat weld” or “welding,” as the ’700 patent required. The district court determined that, properly construed, these terms import a requirement that the attachment “fuse” to the guard panel. The district court relied on the specification and standard dictionaries. Because Amerimax’s products did not involve fusing, they did not literally infringe the ’700 patent.
The district court then considered infringement under the DOE and held in favor of Amerimax under two rationales. First, welding and gluing are not equivalent because they accomplish a different result in a different way. Welding allows molecules of two objects to interface, whereas gluing introduces a third substance. Second, prosecution history estoppel precluded L.B. Plastics from invoking the DOE, namely, L.B. Plastics had knowledge of other means of attachment, but limited its claims to “hot weld[ing]” or “welding” the layers of its gutter guard.
On appeal, the Federal Circuit affirmed the district court’s claim construction and grant of SJ of noninfringement, both literally and under the DOE. Because of the scarcity of intrinsic evidence, the Federal Circuit relied on general and technical dictionaries to confirm the claim construction of the term “weld.” Having found that the district court properly construed the term, the Federal Circuit then turned to infringement. The Federal Circuit first affirmed the district court’s grant of SJ regarding literal infringement, citing the district court’s proper claim construction.
Regarding the DOE, the Federal Circuit reiterated its own precedent that held “that when a specification excludes certain prior art alternatives from the literal scope of the claims and criticizes those prior art alternatives, the patentee cannot then use the doctrine of equivalents to capture those alternatives.” Slip op. at 9. Applying that principle to the facts, the Federal Circuit recognized that the specification of the ’700 patent criticizes prior art attachment means, namely, it describes prior art attachment means as “less effective, and more costly, time consuming, and labor intensive.” Moreover, the Court found that “[t]here is no question but that the prior art attachment means included adhesives; thus the specification must be read to criticize the use of adhesives as attachment means.” Id. at 10. Accordingly, L.B. Plastics could not use the DOE to include adhesive attachments. The Federal Circuit thus affirmed the district court’s grant of SJ of noninfringement.