                       Types of Patents

    The U.S. Patent and Trademark Office (PTO) issues several

    different types of patent documents offering different kinds

    of protection and covering different types of subject matter.

    A recently issued PTO patent document is one of six types,

    generally described below. See U.S. Code Title 35 - Patents, for

    a full description of patents and patent laws.

        *     Utility Patent-  Issued for the invention of a new and

              useful process, machine, manufacture, or composition of

              matter, or a 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 application

              filing ++, 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 Patent-  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 of patent grant.  Design patents are not

              subject to the payment of maintenance fees.

        *     Plant Patent-  Issued for a new and distinct, invented

              or discovered asexually reproduced plant including

              cultivated sports, mutants, hybrids, and newly found

              seedlings, other than a tuber propagated plant or a

              plant found in an uncultivated state, it permits its

              owner to exclude others from making, using, or selling

              the plant for a period of up to twenty years from the

              date of patent application filing ++.  Plant patents

              are not subject to the payment of maintenance fees.

        *     Reissue Patent-  Issued to correct an error in an

              already issued utility, design, or plant patent, it

              does not affect the period of protection offered by the

              original patent.

        *     Defensive Publication (DEF)-  Issued instead of a

              regular utility, design, or plant patent, it offers

              limited protection, defensive in nature, to prevent

              others from patenting an invention, design, or plant.

              The Defensive Publication was replaced by the Statutory

              Invention Registration in 1985-86.

        *     Statutory Invention Registration (SIR)-  This document

              replaced the Defensive Publication in 1985-86 and

              offers similar protection.

    ++   Although, the length of utility and plant patent protection

    (patent term) was previously seventeen years from the date of

    patent grant, utility and plant patents filed after June 8, 1995

    now have a patent term of up to twenty years from the date of

    filing of the earliest related patent application. Utility and

    plant patents which were applied for prior to June 8, 1995, and

    which were or will be in force after June 8, 1995, now have a

    patent term of seventeen years from the date of patent grant or

    twenty years from the date of filing of the earliest related

    patent application, whichever is longer.  Utility patents are

    subject to the payment of periodic maintenance fees to keep the

    patent in force. Patent terms can be extended under some specific

    circumstances.  See the U.S. Code Title 35 - Patents for a full

    description of patent laws.

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    Questions regarding this web page should be directed to:

    (address as of 6/2000)

                 U.S. Patent and Trademark Office

                 Information Products Division

                 Technology Assessment and Forecast Branch

                 PK3-Suite 441

                 Washington, DC  20231

                 tel (703) 306-2600

                 FAX (703) 306-2737

    _______________________________________________________________________________________

    SOURCE:   U.S. PATENT AND TRADEMARK OFFICE

              Technology Assessment and Forecast data base    (1 June 2000)