Structural Equivalence Need not Be in Written Description

In Freeman, et al. v. Gerber Products Company, et al. (Fed. Cir. January 6, 2005, non-precedential) the lower court had found the figures of the ’347 patent insufficient to disclose structure corresponding to a means-plus-function limitation, reasoning that the structure must be identified in the language of the written description or the prosecution history. The lower court therefore determined that these claims were indefinite in scope and therefore invalid as a matter of law under 35 U.S.C. § 112, ¶ 2. The Federal Circuit disagreed:

In each of the cases relied upon by Gerber, the patent specification
disclosed multiple structures potentially capable of performing the recited function, but the specification expressly discussed and thus clearly linked only a subset of those structures to the recited function. Most importantly, none of these cases states that the patent drawings may not be consulted in determining whether there is adequate disclosure of structure for performing a function recited in a means-plus-function claim. On the contrary, our cases make it clear that patent drawings may be consulted.

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Thus, in this case, the only structure disclosed in the specification of the ’347 patent that is capable of performing the function of "selectively maintaining said closure in covering relation with said container," is the structure disclosed in Figures 2 and 5. That structure consists of the configuration of the closure (10) with the container (11), as represented in Figures 2 and 5. Likewise, the only structure disclosed in the ’347 patent that is capable of performing the function of "attaching the thin membrane to an inner surface of the closure," is the structure disclosed in Figure 2. That structure consists of the configuration of the membrane (13) and the inner spout (12), as represented in Figure 2. We therefore conclude that the district court erred in ruling that the specification lacks disclosure of structure which one skilled in the art would understand as being adequate to
perform the functions of "selectively maintaining said closure in covering relation with said container" and "attaching the thin membrane to an inner surface of the closure." It was this ruling which formed the basis for the court’s determination that the claims asserted by Freeman against Gerber Products were indefinite.

The Federal Circuit remanded the case to the district court for further proceedings "beginning with the construction of the asserted claims."