Thorner and the (Not So) Bright Line Rules of Claim Construction

by Dennis Crouch

The Federal Circuit’s 2012 decision in Thorner v. Sony Computer Entertainment America LLC, 669 F.3d 1362 (Fed. Cir. 2012) has become one of the court’s most cited cases from the past 15 years.  In fact, the decision has over 9,000 citations since being released 12 years ago (according to Westlaw search).  The case did not really make new ground, but is most often cited for Judge Moore’s statement of the clear boundaries for when courts can permissibly deviate from the “plain and ordinary meaning” of claim terms. While the decision presents these as bright-line rules, I would argue that the reality is much more nuanced.

Thorner’s patent (US 6,422,941) covered a “tactile feedback system” for video games – think vibrating controllers. The key dispute centered on two claim terms: whether actuators “attached to” a pad included both internal and external attachments. The district court had limited “attached” to only external attachments, based upon consistent usage of that language in the specification.  However, the appellant thought that the term should be more broadly defined.

Judge Moore’s decision begins by reiterating the fundamental principle that claim terms receive their “ordinary and customary meaning as understood by a person of ordinary skill in the art when read in the context of the specification and prosecution history.” Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Cir. 2005) (en banc).  But she then presents what appears to be a clear binary choice – there are “only two exceptions to this general rule”:

1. Lexicography: “when a patentee sets out a definition and acts as his own lexicographer”
2. Disavowal: “when the patentee disavows the full scope of a claim term either in the specification or during prosecution”

The court emphasizes that acting as lexicographer requires explicit clarity: “To act as its own lexicographer, a patentee must clearly set forth a definition of the disputed claim term other than its plain and ordinary meaning.” quoting CCS Fitness, Inc. v. Brunswick Corp., 288 F.3d 1359 (Fed.Cir. 2002).  Importantly, for the lexicography exception to apply, consistent usage or single embodiment is insufficient: “It is not enough for a patentee to simply disclose a single embodiment or use a word in the same manner in all embodiments, the patentee must clearly express an intent to redefine the term.”

Similarly, disavowal has an equally demanding standard: “The standard for disavowal of claim scope is similarly exacting.” Even direct criticism of an embodiment might not rise to the level of disavowal. Instead, there must be “expressions of manifest exclusion or restriction, representing a clear disavowal of claim scope.”

In the case, the specification consistently used the term “attached” when referring to external attachments and “embedded” for internal components. But the court found this consistency insufficient to redefine the claimed “attached” — holding that consistent usage alone does not demonstrate clear intent to redefine. In rejecting the district court’s narrow claim construction, the court also looked to language in the specification that referenced attachment “to [an] outer surface,” which the court found important — if attachments were always external then there would have been no need to specify “outer.”

The Reality: A False Dichotomy? While Thorner presents lexicography and disavowal as strict exceptions to ordinary meaning, in my view, this framework somewhat misses the mark. The “ordinary meaning” itself is heavily influenced by the specification and prosecution history. As the court notes, we determine ordinary meaning “when read in the context of the specification and prosecution history.” The specification and prosecution history shows how the inventor used the term, what problems they were trying to solve, and the technological context. This shapes our understanding of ordinary meaning before we ever get to asking about the two “exceptions.”  This might have been less true pre-Phillips when the intrinsic evidence was given secondary consideration, but today it is the starting place for claim construction, and the result is that all of this becomes much more of a flexible continuum.

The Federal Circuit’s 2016 decision in Profectus Technology LLC v. Huawei Technologies Co., 823 F.3d 1375 (Fed. Cir. 2016) illustrates how the specification shapes claim meaning even absent formal lexicography or disclaimer. There, the court confronted whether “mountable” in a patent for digital picture frames meant merely “capable of being mounted” (its ordinary dictionary meaning) or required “having a feature for mounting.” The court chose the latter, narrower construction based primarily on how the specification described mounting in every embodiment – each had specific mounting features. Notably, the court did this without finding either of Thorner‘s exceptions. There was no explicit redefinition of “mountable” nor clear disclaimer of designs lacking mounting features. Instead, the court simply concluded that when read “in view of the specification,” the claims did not “permit the expansive construction” proposed by the patentee. This case is one of many demonstrating how the specification’s teachings inevitably color the “ordinary meaning” itself, rather than operating solely through the formal exceptions of lexicography and disclaimer.

Despite my quibbles with the framework, Thorner‘s emphasis on clarity serves important notice functions — and the case also highlights several instances of how stray words in the specification or prosecution history can dramatically shift the claim construction outcome later in litigation.