Indefiniteness has for decades enjoyed a reputation as the Rodney Dangerfield of patent defenses: It gets no respect. The U.S. Supreme Court’s decision to hear an appeal in Nautilus Inc. v. Biosig Instruments Inc. may attract new attention to indefiniteness. But regardless of the outcome, the defense is already catching on when applied to “means-plus-function” terms, especially with respect to computer-implemented inventions, which make up the lion’s share of business-method patents. 715 F.3d 891 (Fed. Cir. 2013), cert. granted, Docket No. 13-369 (U.S. Jan. 10, 2014).
Already, more than 70 percent of patents reviewed under the America Invents Act postgrant review reforms implicate electrical or computer patents. The ax most frequently raised to invalidate such patents is the patentable subject-matter challenge under 35 U.S.C. 101, with prior-art invalidation close behind. The standard for patentable subject-matter under Section 101 has enjoyed considerable attention in recent years, and is set to gain still more when the Supreme Court hears the latest in a recent string of Section 101 cases later this year. Meanwhile, lurking quietly in the claims of many of these patents is a defect that is garnering little attention; namely, indefiniteness due to unsupported means-plus-function claiming.
