Among the many techniques used by registered patent practitioners to benefit their clients is the minimization of prosecution history estoppel. They know that whatever you say to the patent office can be used against you, typically to unfavorably narrow your claim scope. Beware, however, that the use of this technique must be used judiciously, as it often increases the difficulty and associated cost to get the patent issued. In this regard, a recent Federal Circuit case In re Google Technology Holdings LLC presents an interesting lesson.

The applicant's specification arguably contained definitions for certain key claim terms that could have been relied on to distinguish the claims from the art cited by the examiner. In responding to the examiner and appealing to the Board, the applicant chose instead to argue merely that the cited art's teachings failed to satisfy the claim limitations. After the Board affirmed the examiner's rejections, applicant appealed to the Federal Circuit, arguing the PTO's construction of the claim terms was inconsistent with the aforementioned definitions in the specification. The Federal Circuit held (not for the first time) that the applicant forfeited those arguments by failing to make them to the PTO when they had the chance.

Of course, hindsight is 20/20 and the applicant couldn't have known ahead of time that the Board would side with the examiner. But when reaching the appeals stage we need to put our prosecution history estoppel concerns in perspective, cognizant that whatever arguments we might choose to omit will be forfeit if we lose.

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