Five Common Mistakes of Patent Prosecution from the Enforcement Perspective (Part 2)

Mistake #2: Means-Plus-Function

The second common mistake is improper use of means-plus-function terms in the claims. Means-plus-function elements require that the specification must permit one of ordinary skill in the art to know and understand what structure corresponds to the means limitation. Some improper claims are in means-plus-function form, but the specification does not disclose a corresponding structure. This may seem to be a no-brainer, but you would be surprised how often this happens, especially in software patents.

Examples
• United States Patent No. 5,404,505: “database editing means . . . for generating a hierarchically arranged set of indices… and for embedding said indices in said information database.” And the specification discloses corresponding “software.”

Consequence
• Invalid for lack for definiteness.

Case Study

In Finisar v. DirecTV Group, Inc., 523 F.3d 1323 (Fed. Cir. 2008), the patent at issue is United States Patent No. 5,404,505, and claim 1 recites ““database editing means . . . for generating a hierarchically arranged set of indices… and for embedding said indices in said information database.” The specification discloses corresponding “software.”

The Federal Circuit finds this claim invalid for lack of definiteness. Referring to the part of the specification regarding “software 132,” it found that “[t]his passage provides no description… of structure corresponding to the claimed function” and “software,” without more, is not the requisite structure. Id. at 1340-41.

Solution

Avoid drafting a means-plus-function claim and use alternative approaches. If you have to, always include a corresponding structure.

(TO BE CONTINUED)