Why don’t patent specifications state their expiry date?

Duncan Bucknell’s site updates:

I was speaking to a friend the other day about freedom to operate clearances and she raised an incredibly good point:

Why don’t patent specifications quote the patent’s expiry date on their front cover? This is one of the most important facts about a patent, yet no patent office publishes this on the document.

Why not?

  • If the patent office is concerned about getting it wrong, then there’s an even bigger issue at stake;
  • If its because the expiry date is simple to work out - then that’s probably not so simple. Many North American patents are still under the old 17 years from grant system, and Divisionals / Continuations etc take their term from the date of filing the original parent - which is not always evident from the specification (and nor is the priority date always available on the front page).

The system would be even better if any…


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