Anticipate This!™ | Patent and Trademark Law Blog

Are You Sure You Want Six Paragraphs?

Posted in Statute Commentary by Jake Ward on May 23, 2006

For a variety of reasons, many practitioners don’t.  35 U.S.C. § 112, sixth paragraph, has been a subject of contentious debate in patent practice.  The AIPLA has previously passed a Resolution to amend Section 112, sixth paragraph.  See AIPLA Bulletin, October-November-December 1994, 137-138.  Additionally, the ABA had previously considered a Resolution to delete the paragraph altogether.  See ABA Intellectual Property Law Section Proposed Resolution 152-3, Deletion of Sixth Paragraph of 35 U.S.C. Sect. 112. 

Why, you may ask?  Well let me explain. 

The sixth paragraph of Section 112 states:  “An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.”

The PTO, in making a determination of patentability used to interpret a “means or step plus function” limitation by giving it the “broadest reasonable interpretation.” Under the former practice, a limitation was interpreted as reading on any prior art means or step which performed the function specified in the claim without regard for whether the prior art means or step was equivalent to the corresponding structure, material or acts described in the specification. 

Those days are long gone, however, and the PTO currently interprets means-plus-function language in accordance with the CAFC rulings in In re Donaldson, 16 F.3d 1189 (Fed. Cir. 1994) and In re Dossel, 115 F.3d 942 (Fed. Cir. 1997).  According to the guidelines at MPEP 2181, the PTO interprets means-plus-function claims in accordance with the corresponding structures, materials, or acts describe in the specification, and equivalents thereof.  Means-plus-function elements are therefore limited to what is disclosed in the written description and equivalents.

Well, you many notice that the PTO guidelines for interpreting means-plus-function language can result in some interesting and problematic situations.  For instance, it is technically possible for patents covering different inventions to issue with identical claims, since the claims are distinguished during prosecution through incorporation of “corresponding structures” from the specification! Furthermore, these guidelines can constrain the scope of the claims to no more than the preferred embodiment regardless of the actual scope of the invention!  There is also serious risk of indefiniteness related to the questions of what disclosure and how much of the disclosure should be incorporated.

As far as I am aware, these issues continue to be relevant. Although I am not in favor of completely removing the paragraph, since the section could be very useful in providing the true scope of an applicant’s invention (without the need for listing a multitude of alternatives in the specification), the paragraph needs some well-planned revising to avoid the aforementioned problems.   

As a potential topic for discussion or future posts, I’m curious whether the proposed Patent Reform Act of 2005 or other patent legislation affects this issue?

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