The April 2010 edition of Patent Happenings,® written by the author of the Annotated Patent Digest, presents concise summaries of important developments in U.S. patent law occurring during the months of January through March 2010. Developments include:

1) Post Seagate cases show that the failure to obtain an opinion of counsel still weighs heavily in determining whether to enhance damages;

2) Using royalty rates in licenses given to settle infringement actions as evidence of a royalty rate in a hypothetical negotiation;

3) Accused infringer’s failure to challenge scope of a permanent injunction when appealing a final judgment precluded later challenge to the injunction’s scope when defending against a charge of contempt;

4) Federal Circuit overrules PTO’s methodology of calculating patent term adjustments where Period A delays “overlap” Period B delays.