During the term of a utility patent, maintenance fees must be paid in order to sustain the patent. Utility patents are, by far, the most common type of patent issued by the U.S Government. To be eligible design patent, an invention must be novel, non-obvious and ornamental. In other words, the design must no serve a primarily functional purpose. The outward visible feature of a new light fixture, for example, might be the subject of a design patent.
Design patents expire at the conclusion of fourteen from the date of the grant of the patent.
Design patents are no subject to maintenance fee payments. To qualify for this type of patent, the discovery or invention must be novel, distinct, and non-obvious. Plant patents have a duration of twenty years from the date of filling the plant patent application. Patentable Inventions Not all inventions are patentable. An invention must fall within one of four categories provided in the U.S. patent laws.