Four statutes decide whether an invention can be patented

Patentability comes down to four questions, each from a different section of Title 35 of the US Code. Each one is applied to your claims, the numbered statements at the end of a patent that define what it covers.

Section 101: is it the right kind of thing?

Patents cover any "new and useful process, machine, manufacture, or composition of matter" (35 U.S.C. § 101). The next lesson covers what falls outside that list.

Section 102: is it new?

Your invention is compared with prior art, the earlier work the law counts against you. The current version of this section applies to applications filed on or after March 16, 2013 (MPEP 2159). The test date is your effective filing date, which is set claim by claim (35 U.S.C. § 100(i)). Prior art is anything "patented, described in a printed publication, or in public use, on sale, or otherwise available to the public" before that date, plus earlier-filed US patents and published applications naming another inventor, subject to the exceptions in section 102(b) (35 U.S.C. § 102).

Section 103: is it more than obvious?

A claim can be new and still be too small a step. Graham looks at the prior art, the differences from it and the level of skill in the field, along with secondary considerations such as commercial success, long-felt need and failure of others.

KSR rejected a rigid test. An improvement must be "more than the predictable use of prior art elements according to their established functions." Yet a claim "is not proved obvious merely by demonstrating that each of its elements was, independently, known."

Section 112: did you teach it?

The application must describe the invention, enable others to make and use it, and end in definite claims (35 U.S.C. § 112). Definiteness means the claims tell skilled readers their scope with "reasonable certainty" (Nautilus), a standard that replaced "insolubly ambiguous." Best mode, the inventor's preferred way of carrying out the invention, remains a requirement but is no longer a ground of invalidity (35 U.S.C. § 282).

Two different readers

Your claims will meet two audiences. The patent examiner gives them their broadest reasonable interpretation, and courts construe them differently (MPEP 2173). In our judgment, you should write for both.