Can a reissue application add new matter to the original patent?

No, a reissue application cannot add new matter to the original patent. This is a fundamental principle in patent reissue law. According to MPEP 1412.01:

No new matter may be introduced into an application for reissue.

This means that all aspects of the reissue claims must be supported by the disclosure in the original patent. Any attempt to introduce new subject matter that was not described in the original patent will be rejected under 35 U.S.C. 251.

To learn more:

• reissue application
• new matter
• patent law
• 35 U.S.C. 251