Description of “The Invention” in Specification Limits Claim Construction

In the Claim Construction Order (dated September 18, 2017) in Gutterglove, Inc. v. American Die and Rollforming (Case 2:16-cf-02408-WHO, EDCA), the Court read a limitation from the specification into the claim construction of the claim element “corrugated with ridges” to match what was described as “this invention” in the patent specification.  Further, the Court held that a claim construction based on the specification’s description of the “this invention” also nullified the Doctrine of Claim Differentiation. This case is another reminder that a description of the “invention” should generally be avoided.

Claims 1 and 2 of US9,021,747 read as follows:

1. A leaf preclusion system for a roof gutter having a gutter lip for keeping leaves and other debris out of the roof gutter while allowing water to pass thereinto, comprising: a sheet of fine mesh material; said sheet of fine mesh material having an upper edge adapted to be located above a lower edge and with said sheet of fine mesh material overlying the roof gutter; said sheet of fine mesh material being corrugated with ridges extending at least part of the way from said upper edge to said lower edge and wherein said lower edge being adjacent the gutter lip when the system is in use, wherein the water is allowed to pass through said sheet of fine mesh material into the roof gutter,

wherein at least one of said ridges extends from at least one of said upper edge and said lower edge.

2. The system of claim 1 wherein said ridges of said sheet of fine mesh material extend substantially perpendicular to said upper edge of said sheet of fine mesh material.

The plaintiff proposed that “corrugated with ridges” be construed according to its plain and ordinary meaning.  The defendant proposed a definition requiring that the ridges extend “perpendicular to a long axis of the gutter.”

The Court held that the specification (specifically, the Summary of the Invention) described that “this invention…includes a filter layer…Strength is provided to the filter member by providing a corrugated form…These corrugations extend perpendicular to a long axis of the gutter and parallel with the direction that water is migrating off of the roof.”  Based on this statement in the specification, the Court interpreted “being corrugated with ridges” to extend “perpendicular to a long axis of the gutter.”  The Court based their reasoning on the following line of cases:

Because the limitation refers to the invention and not just a preferred embodiment, the specification mandates that the corrugated ridges must run parallel, and must extend perpendicular. E.g., Microsoft Corp. v. Multi–Tech Sys., Inc., 357 F.3d 1340, 1351–52 (Fed. Cir. 2004) (construing claim to require feature that was “central to the functioning of the claimed invention”); Alloc, Inc. v. Int'l Trade Comm'n, 342 F.3d 1361, 1369–70 (Fed. Cir. 2003) (construing claim to include limitation because “very character of the invention” required that the limitation be part of every embodiment); Toro Co. v. White Consol. Indus., 199 F.3d 1295, 1300–01 (Fed. Cir. 1999) (construing claim to require a particular configuration where specification described the importance of the configuration and did not disclose others).

Further, since dependent claim 2 specifically claims that the ridges “extend substantially perpendicular to said upper edge of said sheet,” the Plaintiff argued that the Doctrine of Claim Differentiation prevented a claim construction of claim 1 that includes the limitation of dependent claim 2.  However, the Court noted that the Doctrine of Claim Differentiation is only a presumption, and in this case, since the specification characterized “the invention,” this characterization overcame the presumption in favor of claim differentiation. 

This case is another reminder that the use of “patent profanity” should be avoided in patent specifications.  Such terms include “the invention,” as in this case, and also includes terms such as “requires,” “necessary,” “must,” etc.

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