What are the different series of U.S. patents?

The different series of U.S. patents include:

• X-Series: Approximately 10,000 patents issued between 1790 and July 4, 1836.
• 1836 Series: Mechanical, electrical, and chemical patents issued since 1836, often called “utility” patents.
• Reissue Series: Reissue patents, numbered with “Re.” prefix.
• A.I. Series: Patents for Additional Improvements issued from 1838 to 1861.
• Plant Patent Series: Patents for certain types of plants, numbered with “P.P.” prefix.
• Design Patents: Patents for designs, numbered with “D.” prefix.

As stated in the MPEP, “The date of patenting given on the face of each copy is the publication date and is the one usually cited. The filing date, in most instances also given on the face of the patent, is ordinarily the effective date as a reference.“

To learn more:

• U.S. patents
• patent series
• X-Series
• 1836 Series
• Reissue Series
• A.I. Series
• Plant Patent Series
• Design Patents