A recent federal circuit opinion reaffirmed a longstanding rule permitting patent owners to use a reissue proceeding (35 USC §251) in the United States Patent and Trademark Office (USPTO) as a hedge against future invalidity challenges.

In In re Tanaka, __ F.3d __, 2011 U.S. App. LEXIS 7739 (Fed. Cir. Apr. 11, 2011), the patentee filed a reissue application before the USPTO. Originally, the patentee sought to broaden the scope of the patent’s independent claims. However, he later abandoned that attempt, choosing instead to leave the patent’s original claims untouched, instead adding a new claim that was dependent on – and narrower in scope to – existing independent claim 1. The patentee’s declaration stated “because I did not fully appreciate the process of claiming according to U.S. practice, I did not realize that I had claimed more or less than I was entitled to claim.” To the patentee, “more or less” meant he inadvertently failed to include certain dependent claims to which he was rightfully entitled – he was not speaking about the scope of the existing claims.

The USPTO rejected the patentee’s argument, finding that he failed to specify an error that could be properly corrected through reissue. The patentee appealed, and the Board of Patent Appeals and Interferences (BPAI) affirmed. In its opinion, the BPAI held that the reissue statute “disallow[s] reissue applications that simply add narrow claims to the reissue patent when no assertion of inoperativeness or invalidity for the reasons set forth in §251 can be made by the patentee.”1 The BPAI found that the patentee was impermissibly seeking an additional claim on reissue “in order to hedge against the possible invalidity of one or more of the original claims.”2 The patentee appealed to the Federal Circuit.

The court first addressed the rule governing reissue applications. For a reissue to succeed, the court explained that two elements had to be met. First, the original patent had to be “wholly or partly inoperative or invalid.”3 Second, “the defective, inoperative, or invalid patent must have arisen through error without deceptive intent.”4 The court acknowledged that only the first element was at issue.

Citing a half century-old decision, the court stated that adding dependent claims as a hedge against possible invalidity of original claims “is a proper reason for asking that a reissue be granted.”5 The court explained that the term “inoperative” may properly mean “inoperative adequately to protect the invention,” and further that because the “term ‘less’ appears to have been used in the sense of fewer claims than he could properly have made, rather than in the statutory sense of subject matter included within the claims . . . the narrower appealed claims are simply a hedge against possible invalidity of the original claims.”6 This is a proper reason, the court held, for seeking a reissue.

The court reasoned that

[E]ach claim is a separate statement of the patented invention. And each claim of a patent has a purpose that is separate and distinct from the remaining claims. Claims of narrower scope can be useful to clarify the meaning of broader, independent claims under the doctrine of claim differentiation. And dependent claims are also less vulnerable to validity attacks given their more narrow subject matter. Thus, the omission of a narrower claim from a patent can render a patent partly inoperative by failing to protect the disclosed invention to the full extent allowed by law.7

Thus, because the patentee committed an error during prosecution – namely, that he “neglected to seek a narrower dependent claim to which he was entitled” – the patentee may properly apply for a reissue that adds only narrower claims without amending any of the original claims.8 The court reversed the decision of the BPAI and remanded for further proceedings.

In the aftermath of the court’s decision, we will likely see an increase in the number of reissue applications filed in the USPTO. This decision opens the door to patentees who wish to inoculate themselves from invalidity claims (and potentially costly litigation) by seeking a reissue to narrow claims long before such a validity challenge is made. Patentees may also try to use this procedure to claim new commercial embodiments discovered after issuance of the patent and that may not be fully covered by the broader existing claims.