In order for an invention to be patented, it must be new, useful and non-obvious. New means that the invention must not have ever been patented before, even if the patent has expired. Useful means that the patent must do what it claims to do, and that this must be possible. For example, you may not patent a perpetual motion machine. Non-obvious means that the invention should not be something that anyone could just figure out on their own.

Basic Types of Patents

Utility

  • Issued for the invention of a new and useful process, machine, manufacture, or composition of matter, or a new and useful improvement.
  • Approximately 90% of all patents in this category.
  • Term is 20 years.

Design

  • Issued for a new, original and ornamental design.
  • Term is 14 years.

Plant

  • Issued for a new and distinct, invented or discovered asexually reproduced plant.
  • Term is 20 years.

Provisional Patents

From USPTO web site (http://www.uspto.gov/patents/resources/types/provapp.jsp):

"[Filing a provisional patent application]... allows filing without a formal patent claim, oath or declaration, or any information disclosure (prior art) statement. It provides the means to establish an early effective filing date in a non-provisional patent application filed under 35 U.S.C. §111(a). It also allows the term "Patent Pending" to be applied.

A provisional application for patent (provisional application) has a pendency lasting 12 months from the date the provisional application is filed. The 12-month pendency period cannot be extended. Therefore, an applicant who files a provisional application must file a corresponding non-provisional application for patent (non-provisional application) during the 12-month pendency period of the provisional application in order to benefit from the earlier filing of the provisional application. In accordance with 35 U.S.C. §119(e), the corresponding non-provisional application must contain or be amended to contain a specific reference to the provisional application."

In other words, you might wish to consider submitting a provisional patent application, as it allows the term "Patent Pending" to be applied to the invention for one year, and is less expensive than a conventional patent. Just remember that since it a provisional patent expires after one year, the preliminary application must be replaced with a conventional patent application within a year.