From "First-To-Invent" to “First-To-Invent”
On September 16, 2011, the Leahy-Smith America Invents Act, H.R. 1249, became law, resulting in the most sweeping reform of US patent law in 60 years.
On March 16, 2013, the US patent system became a “first-to-file” system, rendering patent rights to the inventor who is the first to file a novel and non-obvious patent application, regardless of the date of invention. Patent applications filed prior to March 16, 2013 will still be examined by the US patent office under the previous “first-to-invent” system, but those filed March 16, 2013 and thereafter will fall under the new “first-to-file” system.
For additional information on the key changes effected by the America Invents Act and the differences between "first-to-file" and "first-to-invent" use the links below:
First-to-File vs. First-to-Invent
America Invents Act - Key Changes