Can A Diaper Pail Become An Important Part Of Patent Law?

Readers might be familiar with a product called a Diaper Genie diaper pail which forms a plastic wrap around a soiled diaper inserted into it, providing benefits of improving hygiene and the aroma around a diaper pail.  It happens that the product is subject to multiple patents and the patent holders sued for infringement.

Commonly in a patent lawsuit, there is a need to construe or define, terminology in the claims.  This process is referred to as a Markman Hearing in which disputed claim terms (phrases or individual words) are defined, usually by the judge after the parties offer possible definitions.  The terms are to be defined as they are used in the claims and the specification.  Extrinsic, or outside evidence, is relied upon only when necessary.  It is often the situation that the outcome of the case rests on the selected definitions.  Importantly, any particular word or phrase generally can only have one definition – that is, however, it is defined, it is to be defined that way consistently, whenever the term is used in the claims or in the specification.

In the diaper pail case (Edgewell Personal Care Brands v. Munchkin, Inc.), a dispute centered on whether a clearance was required between an annular wall and the pail itself when a cassette was installed in the pail.  The claims were directed to the insertable cassette, and the patent application described multiple clearances – including when the cassette was inserted and when it was not.  “Clearance” was a disputed term.  But the application apparently was consistent when using the term “clearance”, despite there being different clearances in different contexts or parts of the diaper pail system.  In a Markman Hearing, the District Court construed the word “clearance” in the claim term “the annular receptacle includes a clearance in a bottom portion of the central opening” as “the space around [interfering] members that remains (if there is any), not the space where the interfering member of cassette is itself located upon insertion” and granted the defendant summary judgment of non-infringement, presumably for not having such a clearance as defined in the Markman Hearing.

On appeal, the Court of Appeals for the Federal Circuit (CAFC) vacated this holding and remanded based on the approach used by the District Court in construing the term.  In reviewing the record at the District Court, the CAFC found that the District Court construed “clearance” more than once, with one of the constructions limiting the construction above to a “‘clearance’ which cannot be filled by an unclaimed interfering member”.  That is, in its holding, the Court used a more narrow definition than the definition determined in the Markman Hearing, and the newly selected definition was neither consistent with the Markman Hearing result nor all the uses of “clearance” in the application, including those not applied in the claims.  In other words, the CAFC determined that the District Court had erred by narrowing the term to not include how it would be used in an unclaimed structure (outside the claims) and had applied this definition, not the one identified in the Markman Hearing, as the reasoning for non-infringement.

Why is this holding important?  First, this case highlights the significance of word precision in patent litigation (and, of course, in authoring a patent application) and how words, even seemingly self-evident words, can hold the difference between winning and losing.

Next, this case illustrates that the author of a patent needs to be diligent in making sure that terms used in the application are used as intended and consistently.  If the terms are used inconsistently, an undesired definition could ensue.  Additionally, because a patent author can be his/her own lexicographer, it can be helpful to explicitly define terms in the application, especially if a term has potential to be disputed. This also illustrates the importance of the patent author and the inventors working closely together to assure the application covers the inventors’ intent.  While the patent holder can succeed in such a dispute, the expense in dollars and time can be substantial.

Also, it is important to recognize that even simple words like “clearance” need to be well defined and consistently used so as to avoid adverse circumstances.  Of course, an applicant wants to have the broadest possible claims, so an applicant is permitted to use a very broad definition.  However, if the definition is too broad, it could result in rejection at the U.S. Patent and Trademark Office during the application’s prosecution.  Again, it is necessary to not only be broad but careful in defining terms.

Finally, something comparatively simple, like a clearance in a diaper pail, can become the subject of a significant issue in determining infringement.  Even seemingly simple patent applications require diligence in crafting.