Utility patents apply to inventions and processes and are distinguished from design and plant patents. Under current patent law, the term of a new utility patent is 20 years, during which the patent holder has the right to exclude others from using, making, selling or distributing the invention or process. However, for utility patents based on applications filed on or after December 12, 1980, the 20-year patent term is subject to the payment of maintenance fees.
Patent maintenance fees must be paid 3 and one-half years, 7 and one-half years, and 11 and one-half years from the date the patent is granted. A fee schedule is maintained in the Code of Federal Regulations, and the fee amounts vary depending on whether or not the patent holder is a small entity, which the United States Patent and Trademark Office (USPTO) defines as an independent inventor, a small business concern, or a nonprofit organization. If they are paid within the six-month period preceding the due dates, the maintenance fees may be paid without surcharge. If the maintenance fees are not paid, the patent will expire. However, there is an additional six-month grace period after the due date within which the maintenance fees may be paid, along with a surcharge, in order to keep the patent in force. The USPTO does not remind patent holders when maintenance fees are due; however, if maintenance fees are not paid on time, the USPTO will attempt to remind a patent holder that maintenance fees may still be paid during the grace period along with a surcharge.
If the maintenance fees are not paid by the end of the grace period, the USPTO allows a patent holder to petition the USPTO for the application of an unintentionally or unavoidably delayed payment and for reinstatement of an expired patent. However, during the time from the expiration and reinstatement of the patent, another person or business may establish rights to use, sell, import or distribute the patented invention or process. Depending on the circumstances, a court may allow such use of the patented invention or process to continue even after the patent is reinstated in order to protect the investment of the person or business, which had a right to presume that the patent had been abandoned when it was allowed to expire.