Infringement, Patent Litigation, Patents

Patent holders can prove infringement by showing that each element of a claim is literally present in an accused infringer’s product or that those elements which are missing have an “equivalent.” The latter approach is permitted under what is known as the “doctrine of “equivalents.”

There is something of a conundrum in the way the courts apply the doctrine of equivalents which was discussed but not resolved by the Federal Circuit in Deere & Co. v. Bush Hog, LLC this past week. A copy of the opinion can be obtained here.

In 1997 the Supreme Court addressed the doctrine of equivalents in the Warner-Jenkinson decision and explained that the doctrine must be applied on an element-by-element basis.  In other words, it is not enough to show that an accused product is equivalent to a patent claim overall. Instead, the doctrine must be applied to individual elements of the claim and cannot be applied so as to “effectively eliminate an element in its entirety.” The application of the doctrine of equivalents in a way that would eliminate a claim element in its entirety is often referred to as “vitiation”.  In other words, the doctrine of equivalents may not be applied so as to “vitiate” or “write-out” a claim element.

The doctrine of vitiation is important in patent infringement cases because vitiation it allows courts to preclude patent holders from arguing infringement under the doctrine of equivalents to the jury.  However, by definition the doctrine of equivalents only comes into play when a claim element is “missing.”  In some sense, there is always an aspect of a claim that is necessarily “vitiated” when the doctrine of equivalents is applied.  So, how can courts apply vitiation without allowing it to effectively swallow the entire doctrine of equivalents?

In Deere the Federal Circuit acknowledged this problem and then did little to solve it.  The patent claim at issue involved a “rotary cutter deck” that required two portions of an “upper deck wall” to come “into engagement with” a lower deck wall. The trial court held that “engagement” required “direct contact,” and therefore, that the accused product did not literally infringe the claim.  Having held that “direct contact” was required, the trial court further held that applying the doctrine of equivalents to an accused product lacking such “direct contact” would improperly vitiate the requirement of direct contact.  Based on this holding, the trial court granted summary judgment of non-infringement in favor of the accused infringer.  The Federal Circuit noted that if taken at face value, the trial court’s reasoning would convert vitiation into the proverbial exception that swallows the rule and effectively foreclose the application of the doctrine of equivalents under any circumstances.

The Deere court considered the trial court’s application of vitiation to reflect a “common misperception” and held that vitiation is “not an exception to the doctrine of equivalents.”  Instead of applying vitiation as its own doctrine or exception, Deere instructs trial courts to simply consider the equivalence issue using the standard applicable to summary judgment motions, i.e., to determine whether “no reasonable jury” could find equivalence.

Despite having offered this instruction to trial courts, Deere cites with approval cases that precluded the application of the doctrine of equivalents “where the accused device contains the antithesis of the claimed structure.”  However, this formulation again seems to be one that swallows the doctrine of equivalents.  In many (or all) cases, an alleged equivalent can be characterize as something that is “not” the actual claim limitation.  For example, “indirect contact” could be characterized as the opposite or antithesis of “direct contact.”  In one of the cases cited in Deere, “before” was deemed to be the antithesis of “after.”

One distinction that may be helpful is the distinction between a claim element and a property of a claim element. In Deere the claim at issue required a lower deck wall, an upper deck wall, “front and rear portions” and “right and left-hand end wall structures.”  In Deere there was no dispute that these elements were present in the accused product.  Instead, the parties disputed only whether the elements interacted in the manner called for by the claim.  Thus, Deere seems to reflect a distinction between whether the accused product includes structures that could potentially correspond to those that are claimed versus particular properties of those structures.  Of course, this distinction begs the question of what defines a “structure” and how a “structure” can be distinguished from its properties, but it may be a distinction that is helpful for litigants in some circumstances.

Unfortunately, Deere provides little insight into whether and under what circumstances courts should find that an equivalence argument improperly writes out a claim limitation.  If anything, Deere appears to diminish the applicability of the vitiation doctrine and may make it easier for patent holders to get to the jury with an infringement case that relies on the doctrine of equivalents.