After filing a patent application and becoming “patent pending,” a patent is examined by the United States Patent and Trademark Office to ensure the requirements for patentability are met.

This can take a little as six months for simple design patents, to between 12 and 24 months for mechanical utility patents. Complex electronic or pharmaceutical product patents can take even longer.

The U.S. Patent and Trademark Office will normally challenge an application at least once. The inventor or his representative must provide an answer, a legal argument, or an amendment to the application.

Although the Patent Office has a goal of issuing patents within 18 months, this goal is missed as often as it is met. Once a patent is issued, it becomes public knowledge.