Q: can I copy a patent after the 20 year period

A: In the United States, for utility patents filed on or after June 8, 1995, the term of the patent is 20 years from the earliest filing date of the application on which the patent was granted and any prior U.S. or Patent Cooperation Treaty (PCT) applications from which the patent claims priority. After those 20 years, their rights fall in public domain and you are free to use it.

However, you should check and make sure you wouldn’t be infringing on any continuations, continuation in part, divisionals or other patents.

While it might seem straightforward, if you’re planning on investing time and money on making these amplifiers, I highly recommend speaking with a patent professional to make sure you’re not infringing on anyone’s rights. The attorney can also help you design around what’s currently protected if needed.

A: (Adding to Ms. Gulicks sensible answer.) There is the added complication of Patent Term Adjustment (PTA), this extends the patent term beyond the 20 years from the first non-provisional application in the chain.

The PTO is supposed to meet certain milestones like a first action on the merits by 14 months from filing. If they miss the milestones, the system awards the patent owner a day of extra term for each day that the PTO was late to compensate the patent owner. The PTA process is complicated as there are debits for the applicant missing a target too and some days the PTO is missing more than one milestone and they do not double count the day. Fortunately, the number of days of PTA is listed on the face of the patent (below the assignee). Patent term adjustment can be zero days, just a few days all the way up to several years when the process took much longer than the prescribed rate.

A further complication applies to divisional applications or continuations as they may have their dates linked to the expiration date of an earlier application. So if there is both PTA and a notice of a terminal disclaimer, you should contact a patent attorney to help you sort this out.

There is yet another type of extension to term called Patent Term Extension but that type of extension is more common for items that need government approval. You may want to look at Public PAIR to see if there is any reference to this.

Finally, it is possible that the term was extended by PTA and not clipped by a terminal disclaimer but was ended early for failure to pay a maintenance fee or some other reason. This would be visible in Public PAIR. It is a shame that this simple question leads to such a long answer.

I hope this helps.

Kevin E Flynn