As a result of looking beyond the claims, however, some words and phrases, when used in the patent specification or in communications with the U.S. Patent and Trademark Office (USPTO), can inadvertently lead a court to attach an unintended (and sometimes unfavorable) meaning to a claim term.  While perfectly appropriate for day-to-day conversations, when used in a patent specification, these words and phrases are considered “patent profanity.”  Using “patent profanity” opens the door for reading limitations into patent claims and limiting the range of protection afforded by the patent.

Accused infringers can use instances of “patent profanity” in the asserted patent to suggest a narrow claim scope to the court.  For example, T-Mobile USA, Inc. (T-Mobile) escaped an infringement verdict due to its opponent’s use of the phrase “very important feature” in its patent.  In that case, the patentee described a direct parallel bus interface of its invention as a “very important feature” in the patent specification.  This allowed T-Mobile to argue that because its product did not contain this “very important feature,” it did not infringe the patent-at-issue.  Persuaded by T-Mobile’s arguments, the court limited the scope afforded by the patent’s claims to include direct parallel bus interfaces and found in favor of T-Mobile.  Inpro II Licensing, S.A.R.L. v. T-Mobile USA, Inc., 450 F.3d 1350 (Fed. Cir. 2006).

Courts can also look to communications with the USPTO to interpret claim scope.  In a recent case, Mylan Pharmaceuticals, Inc. (Mylan) persuaded the court to limit Pharmacia & Upjohn Company’s (Upjohn) claim scope based on Upjohn’s use of “patent profanity” in a communication with the USPTO.  Mylan pointed out that in a response to a prior art rejection, Upjohn argued that “the use of spray-dried lactose is a critical feature of the present invention,” and that “the key feature of the present invention is the particular type of lactose employed in the composition.”  After considering Mylan’s arguments for a narrow reading of the claims due to Upjohn’s use of the terms “critical feature” and “key feature,” the court interpreted Upjohn’s claim to require spray-dried lactose.  Because Mylan’s product lacked this “key feature,” the court found no infringement on Mylan’s behalf.  Pharmacia & Upjohn Co. v. Mylan Pharm., Inc., 170 F.3d 1373 (Fed. Cir. 1999).

Another recent case demonstrates that care must be taken when amending patent claims.  Upon amending its claims, Biovail Corporation International (Biovail) included the term “necessarily” in its associated remarks to the USPTO.  Biovail’s opponent, Andrx Pharmaceuticals, Inc. (Andrx), capitalized on the use of the term “necessarily” to argue for a narrow claim construction.  Andrx argued that Biovail’s patent should be limited based on an argument made in response to a rejection that a bead produced by the claimed extrusion-spheronization process “is necessarily a homogeneous bead composition.”  The court agreed with Andrx, causing Biovail to lose priority for a later-filed application and allowing Andrx to escape infringement.  Biovail Corp. Int’l v. Andrx Pharm., Inc., 239 F.3d 1297 (Fed. Cir. 2001).

The Federal Circuit once again highlighted the effects of “patent profanity” in Research Corp. Technologies, Inc. v. Microsoft Corp., 627 F.3d 859 (Fed. Cir. 2010).  In this recent case, Research Corporation Technologies, Inc. (Research Corp.) filed a patent seeking to claim priority of earlier-filed parent applications.  However, Microsoft Corporation (Microsoft) argued that Research Corp.’s use of the characterizations “the present invention” and the “objects of the invention” in the specification of the parent applications strongly suggested that the claimed invention is limited in scope.  Because of these assertions, the court sided with Microsoft and read the claims narrowly.

The ultimate goal in patent drafting and prosecution is to afford inventors an opportunity to realize the full scope of protection for their intellectual property.  The use of “patent profanity” during application drafting and prosecution, however, can undermine that opportunity by leading to narrow interpretations of claim terms.  To prevent some of the outcomes described above, patent drafters and prosecutors should minimize the use of words of characterization when describing the invention.  These types of words include, but are not limited to, chief, majority, critical, essential, necessary, solely, only, main, significant, principal, important, fundamental, and vital.  Doing so will help to prevent future unintentionally narrow interpretations of claims.