Reassessing How to Draft “Preferred Embodiments” in Patent Applications

Holding

In Howmedica OsteonicsCorp. v. Zimmer, Inc., Nos. 2015-1232, -1234, -1239, slip op. at 15-16 (Fed. Cir. May 12, 2016), the Federal Circuit held that introductory clauses such as “In the preferred embodiment” may “limit only the sentences in which they are located” and not the succeeding sentences in the same paragraph.

Key Facts and Observations

The dispute involves the “essentially midway” construction in U.S. Patent No. 6,475,243 (“’243 patent”) concerning a socket assembly used in prosthetic hip implants.

The patent owner argued that the “essentially midway” language in the written description concerns a preferred embodiment and cannot be used to limit the claims. Slip op., at 15.  Specifically, the patent owner reasoned that introductory clauses such as “In the preferred embodiment” apply not only to the sentences in which they are located, but also to the succeeding sentences in the same paragraph. Id.

The Federal Circuit disagreed, finding that “context reveals that such introductory clauses limit only the sentences in which they are located in this case.” Id. at 15-16. The Federal Circuit also gave little weight to the generalized disclaimers such as “The invention will be understood more fully . . . in the following detailed description of preferred embodiments of the invention” and “It is to be understood that the above detailed description of preferred embodiments of the invention is provided by way of example only.” Id. at 16.

A closer review of the relevant language in the ’243 patent reveals that the Federal Circuit’s holding 

on “preferred embodiments” may not be as far-reaching as it appears. Specifically, the “preferred embodiments” language appears in the middle of a paragraph in the ’243 patent. See, e.g., ’243 patent, col. 6, l. 64 – col. 7, l. 17. Therefore, the Federal Circuit found that “context reveals that such introductory clauses limit only the sentences in which they are located in this case.” Slip op. at 15-16 (emphasis added).

Practice Tips

In light of this opinion, when drafting preferred embodiments, patent attorneys should consider (1) using the “In a preferred embodiment” language in the beginning of a paragraph, and/or (2) adding another generalized disclaimer such as “The discussion of the preferred embodiments herein shall not be construed to limit only the sentences in which introductory clauses such as ‘In a preferred embodiment’ are located.”