# Thorner v. Sony: The Two Exceptions to Plain and Ordinary Meaning

> Claim terms keep their ordinary meaning unless the patentee is its own lexicographer or clearly disavows scope. Consistent usage alone is not enough.

Topic: Patents  |  Author: Lidiia Levitska  |  Source: Intellectual Property Law (outsideipcounsel.com)
Canonical: https://outsideipcounsel.com/blog/thorner-v-sony-lexicography-disavowal-exceptions/


*Thorner v. Sony Computer Entertainment America LLC*, 669 F.3d 1362 (Fed. Cir. 2012), decided February 1, 2012, is one of the most frequently cited claim-construction opinions of the modern era. It does not announce a new test. Its influence comes from a crisp restatement of an old one: claim terms carry their plain and ordinary meaning to a person of ordinary skill in the art, and there are exactly two ways a patentee can escape that default. The patentee can act as its own lexicographer, or the patentee can disavow claim scope. Both require a clear and explicit statement. Nothing less will do.

That deceptively simple framework, authored for the panel by Judge Moore, has become the reflexive opening move in thousands of *Markman* briefs. When a party argues that a claim term should be read more narrowly than its ordinary meaning, the response begins with *Thorner*: show me the definition, or show me the disavowal.

## At a glance

- **Case:** *Thorner v. Sony Computer Entertainment America LLC*, 669 F.3d 1362 (Fed. Cir. 2012)
- **Decided:** February 1, 2012; opinion by Judge Moore (panel: Chief Judge Rader, Judge Moore, and District Judge Aiken sitting by designation); vacated and remanded
- **Holding:** A claim term keeps its plain and ordinary meaning unless the patentee clearly redefines it (lexicography) or clearly and unmistakably disavows claim scope; consistent description of embodiments is not enough.
- **Significance:** Supplies the day-to-day operating rule beneath *Phillips v. AWH Corp.* and is the standard citation for resisting improper narrowing of claim scope.

## The claims and the dispute

Craig Thorner's U.S. Patent No. 6,422,941 claimed a tactile feedback system for computer video games, the technology that makes a controller vibrate in a player's hands. The infringement suit against Sony turned on two claim terms.

The first was "attached to said pad." The specification described vibration-producing "actuators" that were attached to the exterior of a flexible pad and, separately, actuators that were "embedded" within the pad. The district court read "attached to" narrowly, as covering only external attachment, holding that "the specification redefines 'attached' by implication." On that construction the parties stipulated to a judgment of non-infringement, and Thorner appealed. A second term, "flexible," which the district court had construed to mean "capable of being noticeably flexed with ease," was not the basis of the stipulation but was briefed and decided on appeal anyway.

Sony's argument was intuitive. Throughout the specification, the patentee used "attached" when describing devices on the outside of the pad and "embedded" when describing devices inside it. If the inventor consistently reserved "attached" for external mounting, the argument went, then "attached to said pad" should be limited to external mounting. The district court agreed.

## The doctrinal frame: ordinary meaning and its two exceptions

The Federal Circuit rejected that construction, vacating and remanding, and it used the occasion to state the governing rule with unusual economy. Words of a claim are generally given their ordinary and customary meaning as understood by a person of ordinary skill in the art at the time of the invention. This is the *Phillips v. AWH Corp.*, 415 F.3d 1303 (Fed. Cir. 2005) (en banc), baseline. *Thorner* then identified the only two circumstances that displace it.

First, lexicography. A patentee may act as its own lexicographer and give a claim term a meaning other than its ordinary meaning. To do so, the patentee must "clearly set forth a definition of the disputed claim term" other than its plain and ordinary meaning, language *Thorner* draws from *CCS Fitness, Inc. v. Brunswick Corp.*, 288 F.3d 1359 (Fed. Cir. 2002). It is not enough, the court added, for a patentee to disclose a single embodiment or use a word the same way in all embodiments: the patentee must "clearly express an intent" to redefine the term, quoting *Helmsderfer v. Bobrick Washroom Equipment, Inc.*, 527 F.3d 1379 (Fed. Cir. 2008). The definition must be explicit. It is not enough that the specification uses a term in a particular way or supplies examples consistent with a narrower reading.

Second, disavowal. A patentee may disavow the full ordinary scope of a claim term by making a clear and unmistakable disclaimer, either in the specification or during prosecution. Again the standard is exacting. The specification must contain "expressions of manifest exclusion or restriction, representing a clear disavowal of claim scope," a formulation *Thorner* quotes from *Teleflex, Inc. v. Ficosa North America Corp.*, 299 F.3d 1313 (Fed. Cir. 2002). As the court put it, "[t]o constitute disclaimer, there must be a clear and unmistakable disclaimer."

The court's central point was about the burden these exceptions impose. Both exceptions require the patentee to say something clear. Because the patentee is presumed to intend the ordinary meaning of the words it chose, only an explicit redefinition or an unmistakable disclaimer can overcome that presumption. A court may not narrow a claim term simply because the embodiments in the specification are all narrower than the term's ordinary sweep.

## Why consistent usage lost

Applying that frame, the court rejected Sony's argument. Using "attached" consistently to describe external devices did not "redefine" the word to exclude internal attachment, because the specification never said so. And describing external and internal placement with two different words did not "disclaim" internal attachment from the term "attached," because there was no clear expression of exclusion. At most, the specification distinguished two embodiments. Distinguishing embodiments is not disavowing claim scope.

The court drew the line it has policed ever since: there is a difference between the meaning of a claim term and the embodiments disclosed in the specification. The specification is used to understand what the inventor meant by a term, not to import the specific examples into the claim as limitations. *Thorner* is, in this sense, an anti-importation decision. Its animating worry is the recurring temptation to read the preferred embodiment into the claims, a move the Federal Circuit has repeatedly warned against.

The court also addressed a related argument that "attached" should be read narrowly because the specification and dependent claim 10 used "embedded" as an alternative. That did not "require a different result." There was nothing inconsistent about an applicant using the narrower term "embedded," whose plain meaning is "attached within," for internal placement, so its presence did not convert "attached" into an external-only term. The court acknowledged that certain pre-*Phillips* cases had treated the use of two terms as alternatives as an implicit redefinition, but held that any "implied" redefinition "must be so clear that it equates to an explicit one." The court added a structural point: the only flexible embodiment disclosed, a semi-rigid foam seat cushion, had actuators embedded within it, so Sony's construction would have excluded the sole flexible embodiment from a claim reciting a "flexible pad." Because the stipulation of non-infringement rested on the erroneous construction, the court vacated and remanded. It separately held that the district court had improperly limited "flexible" to "noticeably flexed with ease," reasoning that the degree of flexibility is part of the infringement analysis, not claim construction.

## What it changed, and what it did not

*Thorner* did not alter the *Phillips* methodology. It sharpened the exception analysis into a two-part checklist that lower courts and litigants now apply almost mechanically. The value of that clarity is real: it disciplines the argument that a specification's examples silently narrow the claims, and it forces the party seeking a narrow construction to point to actual language of definition or disclaimer.

The tension the opinion surfaces is equally real and has never fully resolved. Later panels have found disavowal where the specification repeatedly disparaged the prior art, described "the present invention" in restrictive terms, or characterized a feature as essential. Reconciling those cases with *Thorner*'s demand for a "clear and unmistakable" statement is the recurring work of claim construction. The line between "the specification consistently describes X" (not enough) and "the specification makes clear the invention is X" (disavowal) is drawn case by case.

## Open questions

*Thorner* states the standard but does not, and cannot, resolve every application of it. How much repetition, and how strong a characterization, converts consistent description into an implied disavowal remains contested. Statements that "the present invention" has a particular feature sit uneasily against *Thorner*'s rule that describing embodiments is not disclaiming scope. And the interaction between prosecution-history disavowal, which can be triggered by arguments made to secure allowance, and the specification-based disavowal at issue in *Thorner* continues to generate fact-intensive disputes. The opinion supplies the rule of decision, not a formula for its outcomes.

## Implications for inventors and businesses

- **Draft definitions on purpose, not by accident.** If a term needs a special meaning, define it explicitly. Do not rely on consistent usage across embodiments to do the work of a definition, because *Thorner* says it will not.
- **Watch the "present invention" language.** Statements that characterize the whole invention, or that disparage alternatives, risk being read as disavowals later. If broad claim scope matters, describe embodiments as examples, not as the invention itself.
- **Do not assume a narrower synonym narrows the broad term.** In *Thorner*, using "embedded" elsewhere in the patent did not shrink "attached," because a narrower alternative term is not a redefinition. Still, drafting two terms as alternatives invites exactly that fight, so choose vocabulary with the argument in mind.
- **Litigate ordinary meaning first.** For an accused infringer seeking a narrowing construction, and for a patentee resisting one, *Thorner* frames the battle: absent an explicit definition or a clear disclaimer, ordinary meaning controls.

## Frequently asked questions

**What are the two exceptions to plain and ordinary meaning?** Lexicography and disavowal. A patentee can redefine a term by clearly setting out its own definition, or can narrow a term by clearly and unmistakably disavowing claim scope in the specification or during prosecution. Absent one of the two, the term keeps its ordinary meaning to a skilled artisan.

**Why was the specification's consistent usage not enough?** The specification used "attached" for external devices and "embedded" for internal ones, but the Federal Circuit held that describing embodiments consistently, without a clear statement redefining or disclaiming, does not meet the exacting standard for lexicography or disavowal.

**How does Thorner relate to Phillips v. AWH?** *Phillips* sets the general methodology for reading claims in light of the specification and prosecution history. *Thorner* supplies the operating rule for when the specification actually overrides ordinary meaning, keeping the two exceptions narrow so patentees are held to the words they chose.

## Authorities and sources

- *Thorner v. Sony Computer Entertainment America LLC*, 669 F.3d 1362 (Fed. Cir. 2012) (No. 2011-1114). [Slip opinion, U.S. Court of Appeals for the Federal Circuit](https://cafc.uscourts.gov/opinions-orders/11-1114.pdf).
- *Phillips v. AWH Corp.*, 415 F.3d 1303 (Fed. Cir. 2005) (en banc), the en banc framework for claim construction that *Thorner* operationalizes.
- U.S. Patent No. 6,422,941, "Universal Tactile Feedback System for Computer Video Games and Simulations," [full-text image via USPTO](https://image-ppubs.uspto.gov/dirsearch-public/print/downloadPdf/6422941).
- Patently-O, ["Thorner and the (Not So) Bright Line Rules of Claim Construction"](https://patentlyo.com/patent/2024/11/thorner-bright-construction.html), on the ongoing tension between ordinary meaning and implied disavowal.