Patents Issued in 1981
- December 29, 1981
- December 22, 1981
- December 15, 1981
- December 8, 1981
- December 1, 1981
- November 24, 1981
- November 17, 1981
- November 10, 1981
- November 3, 1981
- October 27, 1981
- October 20, 1981
- October 13, 1981
- October 6, 1981
- September 29, 1981
- September 22, 1981
- September 15, 1981
- September 8, 1981
- September 1, 1981
- August 25, 1981
- August 18, 1981
- August 11, 1981
- August 4, 1981
- July 28, 1981
- July 21, 1981
- July 14, 1981
- July 7, 1981
- June 30, 1981
- June 23, 1981
- June 16, 1981
- June 9, 1981
- June 2, 1981
- May 26, 1981
- May 19, 1981
- May 12, 1981
- May 5, 1981
- April 28, 1981
- April 21, 1981
- April 14, 1981
- April 7, 1981
- March 31, 1981
- March 24, 1981
- March 17, 1981
- March 10, 1981
- March 3, 1981
- February 24, 1981
- February 17, 1981
- February 10, 1981
- February 3, 1981
- January 27, 1981
- January 20, 1981
- January 13, 1981
- January 6, 1981