What is the difference between a design and utility patent?
Utility: may be granted to anyone who invents or discovers any new and useful process, machine, article of manufacture, or composition of matter, or any new and useful improvement thereof. It generally permits its owner to exclude others from making, using, or selling the invention for a period of up to twenty years from the date of patent was granted and is subject to the payment of maintenance fees. Approximately 90% of the patent documents issued by the PTO in recent years have been utility patents, also referred to as "patents for invention."
Design: Issued for a new, original, and ornamental design for an article of manufacture, it permits its owner to exclude others from making, using, or selling the design for a period of fourteen years from the date the patent was granted. The design patent protects only the appearance of an article, but not its structural or functional features. Design patents are not subject to the payment of maintenance fees.
For more information, see the Manual of Patent Examining Procedures (MPEP), Section 1502.01