What is patent law?

The bargain behind patents

The Constitution gives Congress the power to grant inventors exclusive rights “for limited times” to promote progress. The inventor gets a temporary monopoly; the public gets a full description of the invention, which anyone may use once the patent expires. A patent does not give its owner the right to make the invention — other patents or regulations may still stand in the way — only the right to stop others.

The three types

• Utility — machines, processes, manufactured articles, compositions of matter and improvements to any of them. 20 years from filing, with maintenance fees due at 3.5, 7.5 and 11.5 years.
• Design — the ornamental appearance of an article, such as the shape of a bottle or a phone's screen layout. 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 and business-method claims. Only a human can be named as an inventor; the Federal Circuit confirmed in 2022 that an AI system cannot be, though inventions made with AI assistance can be patented if a person contributed significantly.

The application process

An application includes a detailed description, drawings and claims — numbered sentences that define exactly what is protected. A patent examiner searches earlier patents and publications (“prior art”) and usually rejects some claims at first; the applicant responds by arguing or narrowing them. The process commonly takes two to three years. Total cost for a utility patent, including attorney fees, often runs from about $10,000 for a simple invention to much more for complex technology. Small and micro entities pay reduced USPTO fees.

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Timing rules that catch inventors out

The US is first-inventor-to-file: the filing date, not the date of invention, generally decides priority. A public disclosure, sale or offer for sale by the inventor starts a 12-month grace period in the US — but most other countries have no such grace period, so publishing before filing can destroy foreign rights immediately. A provisional application secures a filing date for 12 months at low cost and is the standard way to buy time; the full application must be filed within that year. International protection usually runs through a Patent Cooperation Treaty application.

Ownership

Patents belong to the inventor unless assigned. Most employers require employees to assign inventions made on the job, and contractors should sign written assignments. Co-inventors each own the whole patent and can use or license it without the others' consent, which is why agreements among co-inventors matter.

Enforcement

Infringement suits are brought in federal court; appeals go to the Court of Appeals for the Federal Circuit. Remedies include damages of at least a reasonable royalty, lost profits where provable, enhanced damages up to treble for willful infringement, attorney fees in exceptional cases, and injunctions in appropriate cases. Defendants frequently challenge validity at the Patent Trial and Appeal Board through inter partes review, which is faster and cheaper than litigating validity in court. Imports can also be blocked through the International Trade Commission.

Patent vs. trade secret

Some inventions — a manufacturing process, a formula — can be kept secret indefinitely instead of patented. Secrecy lasts longer if it holds, but offers no protection against independent invention or reverse engineering. Patents are better for products that reveal how they work once sold.

Practical first steps

Keep dated records of development, avoid public disclosure before filing, use non-disclosure agreements when discussing the invention, and consult a registered patent attorney or agent — only they may represent applicants before the USPTO.

A free USPTO search of existing patents before investing heavily can save a failed application.