What is patent law?

The three types

• Utility — machines, processes, compositions of matter and improvements. 20 years from filing, with maintenance fees.
• Design — the ornamental appearance of an article. 15 years from grant.
• Plant — new asexually reproduced plant varieties. 20 years from filing.

What is required

The invention must be patentable subject matter, new, useful and non-obvious to a person skilled in the field, and the application must describe it well enough for such a person to make and use it. Abstract ideas, natural phenomena and laws of nature are excluded, a line that Alice v. CLS Bank (2014) made decisive for software claims.

Timing rules that catch inventors out

The US is first-to-file: the filing date, not the invention date, decides priority. A public disclosure, sale or offer for sale starts a 12-month grace period in the US — but most other countries have no grace period at all, so publishing before filing destroys foreign rights immediately. A provisional application secures a filing date for 12 months at low cost and is the standard way to buy time.

Enforcement

Infringement suits are brought in federal court; appeals go to the Federal Circuit. Remedies include damages of at least a reasonable royalty, enhanced damages up to treble for wilful infringement, and injunctions in appropriate cases. Defendants frequently respond by challenging validity at the Patent Trial and Appeal Board through inter partes review, which is faster and cheaper than litigating validity in court.