Patentability

Within the context of a national or multilateral body of law, an invention is patentable if it meets the relevant legal conditions to be granted a patent. By extension, patentability also refers to the substantive conditions that must be met for a patent to be held valid.

Requirements

The patent laws usually require that, for an invention to be patentable, it must be:

Patentable subject matter, i.e., a kind of subject-matter eligible for patent protection (also called "statutory patentable subject-matter")

Novel (i.e. at least some aspect of it must be new)

Non-obvious (in United States patent law) or involve an inventive step (in European patent law and under the Patent Cooperation Treaty)

Useful (in U.S. patent law) or be susceptible of industrial application (in European patent law)

Usually the term "patentability" only refers to the four aforementioned "substantive" conditions, and does not refer to formal conditions such as the "sufficiency of disclosure", the "unity of invention" or the "best mode requirement".

Judging patentability is one aspect of the official examination of a patent application performed by a patent examiner and may be tested in post-grant patent litigation.

Prior to filing a patent application, inventors sometimes obtain a patentability opinion from a patent agent or patent attorney regarding whether an invention satisfies the substantive conditions of patentability.

Opposition and reexamination

Many national and regional patent offices provide procedures for reconsidering whether or not a given patent is valid after grant. Under the European Patent Convention, any person can file an opposition provided they act promptly after the patent is granted. In the United States, members of the public can initiate reexamination proceedings. Japan provides similar options.