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  • The opinions, commentary and characterizations provided to this online forum by the authors and moderators are provided for encouraging discussion, thought and debate on important post grant issues. These postings are in no way representative of the opinions of Oblon Spivak et al., or its clients.

The Post Grant Magic of Means Plus Function Claims

Posted On: Nov. 3, 2010   By: Scott A. McKeown
magic-hatHedging against post grant invalidity

Would you ever file a patent application without dependent claims?  I wouldn’t….and for obvious reasons. Dependent claims help present more detailed aspects of a claimed invention. In the prosecution context for example, dependent claims present a variation in claim scope to the examiner. Once searched by the patent examiner, in many cases dependent claims are identified as allowable and provide a simple amendment option, often leading to patent issuance. Likewise, once issued as a patent, dependent claims provide more detailed fallback positions that serve as a hedge against an invalidity attack. It is a rare patent indeed that issues without dependent claims.

Yet, there exists another form of claim that also provides a narrowed presentation of inventive features that is increasingly avoided in patent applications; the means plus function claim. Many practitioners now advocate the avoidance of such claims, but why?

Well, for one, litigators prefer broader, non-mpf claims.  Likewise, mpf claims complicate an infringement case due to their unique claim construction rules. Still others will point to recent case law finding such claims indefinite.  Aristocrat Technologies Australia (ATA) v. International Gaming Technology (IGT) (Fed. Cir. 2008)

While these criticisms are valid, lost in the debate is the fact that in many cases such claims are more likely to withstand invalidity challenges, such as during patent reexamination….isn’t that the point in having narrower claims?

Surely, with cases such as Aristocrat exhibiting the pitfalls of poorly drafted specifications, drafting an application that will support mpf claims can be challenging.

Still, as demonstrated in the Funai appeal discussed yesterday, such claims are more likely to survive a challenge due to their relatively narrow interpretation. While Funai was affirmed on some grounds, the detailed analysis of the mpf claims at issue demonstrates the significant difference in claim construction used for mpf claims. In patent reexamination, the broadest reasonable interpretation (BRI) is not available for these more narrow claims. Instead, features of the specification MUST BE imported to these claims.

As 112 issues are not considered in patent reexamination for original claims, the dangers of Aristocrat indefiniteness are non-existent at the USPTO. Likewise, with most patents subject to litigation now being subject to patent reexamination, a hedge against a liberal application of BRI is quite useful.

The level of difficulty in drafting a patent application that will support proper mpf claims should not discourage Patentees from including these valuable claims as a hedge against invalidity. As most patents of mid-1990s vintage now demonstrate in patent reexamination, these claims can be the difference between winning and losing.

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