Diverging Definitions: Is a Range Exclusive or Inclusive of the Endpoints?
A patent drafter has many choices when deciding how to word a phrase that recites a range of values in an application and claims. For example, “between X and Y,” “range of X to Y,” “from X to Y,” and “up to Y,” are just some of the ways that a range of values could be described. While seemingly simple, these phrases may have a significant impact on claim scope and patentability. For example, when a patent claim indicates a range as being “between X and Y,” does that include X and Y, or exclude X and Y?
The Federal Circuit in Athletic Alternatives Inc., v. Prince Manufacturing, Inc., 73 F.3d 1537 (Fed. Cir. 1996), wrestled with this issue and identified two definitions of “between” that result in the endpoint inclusive versus endpoint exclusive debate: “in the space that separates; in the midst of; or surrounded by” and “from one to the other.” “In the space that separates” would not include the endpoints, whereas “from one to the other” would include the endpoints. The result is one word, defined two different ways, possibly leading to two different results. So, which definition is the correct definition to use? One that is inclusive of endpoints, or one that is exclusive of endpoints? As the case law reviewed herein indicates, depending on the context, it can be either. But by the end of this article, we hope to convince you to carefully consider the facts of each case to avoid the risk that an unwanted definition will be chosen and applied against the Patent Owner.
A Range Inclusive of the Endpoints
In CoorsTek, Inc. v. Reiber, 2011 U.S. Dist. LEXIS 47145 (D. Col. May 2, 2011), the claim phrase at issue read:
2. A tip as in claim 1, having a resistance in the range of 105to 1012ohms.
In its analysis on the scope of the range, the Court cited the Federal Circuit opinion in AK Steel, which indicated that in a range “where the endpoint is numeric (e.g., counting up to ten, or seating capacity for up to seven passengers) the endpoint normally would be included in the computation.” AK Steel Corp. v. Sollac and Ugine, 344 F.3d 1234, 1241 (Fed. Cir. 2003).
Accordingly, the Court in this case held that, “the ordinary meaning of the phrase “from number ‘x’ to number ‘z’ would include the endpoint.” The claimed ranged was construed to be “a range having a value at or between 1 × 105ohms and 1 × 1012ohms, inclusive of both the beginning point and the endpoint.” CoorsTek, 2011 U.S. Dist. LEXIS at 66.
The district court in Parker Compound Bows, Inc. v. Hunter’s Mfg. Co., 2016 U.S. Dist. LEXIS 17878 (W.D. Va. Feb. 12, 2016), reached a similar conclusion where a claim read:
2. The crossbow of claim 1, wherein said limb length L1 is between 13 and 14 inches.
In construing the meaning of “between” and the scope of the disclosed range, the court held that “the scope of the term ‘between’ when used to disclose a limb length or power stroke ‘between’ two numerical values, includes the endpoints.” Parker, 2016 U.S. Dist. LEXIS at 39.
Thus, these cases show that a range including numerical value endpoints has been interpreted to be inclusive of the endpoints.
A Range Exclusive of the Endpoints
Despite construing a range “between 1 × 105ohms and 1 × 1012ohms” to be inclusive of the endpoints, the district court in CoorsTek also interpreted a different claimed range to be exclusive of the endpoints. In that instance, the claim phrase at issue read:
1. A tip having a dissipative material for use in wire bonding machines for connecting leads on integrated circuit bonding pads, wherein said dissipative material has a resistance low enough to prevent a discharge to a device being bonded and high enough to avoid current flow large enough to damage said device being bonded.
Rather than having endpoints with numerical values, the endpoints in this range were expressed in functional terms: a dissipative material having a resistance “low enough” to prevent a discharge to a device being bonded, and a dissipative material having a resistance “high enough” to avoid current flow that could cause damage to the device being bonded. In determining whether or not this range was inclusive of the endpoints expressed in function terms, the court in this case again cited to AK Steel which held that a range may include or exclude the endpoint depending on the context. In AK Steel the Federal Circuit indicated that:
when an object of the preposition “up to” is nonnumeric, the most natural meaning is to exclude the object (e.g., painting the wall up to the door).
AK Steel at 1241.
Because the end points of the range at issue were nonnumeric values expressed in functional terms, the district court in this case concluded that the endpoints may be excluded. The court then analyzed the meaning of dissipative in the context of the range and as it was defined and used throughout the application and determined that “[d]issipative means having an electrical resistance in the range between completely insulative and completely conductive, excluding both endpoints.” CoorsTek, 2011 U.S. Dist. LEXIS at 65.
In addition to demonstrating that a range with numerical endpoints has been interpreted as endpoint inclusive, CoorsTek also shows that a range having nonnumerical endpoints or endpoints expressed in function terms has been construed as endpoint exclusive.
Avoiding the Endpoint Inclusive Versus Exclusive Debate
There are ample opportunities for a practitioner to provide meaning and context to “between” and other phrases used to define a range in a patent application. For example, a “range between X and Y” or even the word “between” can be defined as being inclusive or exclusive of the endpoints. This can be in the form of a separate definition, or a follow-up sentence after a range is defined. For example, the specification could say “a range between X and Y’ includes the endpoints X and Y (or excludes the endpoints X and Y were that desired).
Similarly, claims can be written to explicitly include or exclude endpoints when a range is indicated. Such as using phrasing “from X to Y.” Alternatively, while an independent claim may broadly provide a range “between X and Y,” dependent claims may specifically claim X or Y, with the argument that those dependent claims do not improperly broaden the scope of the independent claim, thus “telescoping” the scope of the claims and providing intrinsic evidence that the range is endpoint inclusive. A danger may be that a trier of fact will disagree and rule the dependent claims improper, leaving the independent claim exclusive of X and Y.
If prosecution is complete, a narrower claim may be pursued through a reissue application that explicitly provides the scope of a claimed range. See In re Tanaka, 640 F.3d 1246 (Fed. Cir. 2011). Although a reissue could provide clarity as to the scope of a desired range, a reissue application reopens prosecution of all claims and therefore should be a carefully considered decision. And it is not clear that the reissue claim reciting X or Y would necessarily be narrower than the original claim “between X and Y.” If that were true, the time limits for a broadening reissue would have to be met.
As has been previously discussed on the Prosecution Blog, here, even the seemingly simplest of words can have a great influence on the meaning and interpretation of a sentence or phrase. Practitioners should carefully consider the language used to define a range. Practitioners may ask whether terms defining ranges could be misconstrued by an infringer and consider whether terms should be eliminated or more clearly defined to address any potential ambiguity around whether endpoints are included or excluded. In the end, why leave it open to a highly skilled opposing counsel or a highly skilled USPTO examiner or PTAB judge, to make a call that may be contrary to what the Patent Owner wants?