Why don't patent specifications state their expiry date?

The Brazilian Patent and Trademark Office, which by the way is completing next year 200 years of patent history in Brazil, does publish the expiry date of the patent at the cover page

Thanks so much, Denis

Good point. Some countries provide an English document that states the effective term of your patent that is granted.  However, the Amercians like to make everything difficult (probably so legal people can charge such high fees to work out simple things). Even the text on the fancy document you get from the USPTO (with the gold stamp) is confusing as to the term of the patent.  It takes a few minutes to figure out what the term really is. 

Thanks Canuckinoz

Soooooo much can happen to a patent after the specification is published. It can lapse, be revoked, be amended or (in the case of pharma and agrichem patents) be extended.  I'd guess that the damage done by erroneously relying on an expire-by date more than outweighs the cost of checking to see whether/when the patent has expired.

Hi Jeremy

Thanks very much.  Couldn't lapse / withdrawal, etc be dealt with by using appropriate (but brief) warning wording alongside the expiry date? 

Also - amendment wouldn't alter expiry and I'm proposing that the front page be re-published if the term is extended.

I'm also very interested to see whether you think it is a good idea or not?  What do you think?

thanks very much

Duncan

Hi Duncan,

Still enjoying your blog. Just posted the answer here:

http://emgill.blogspot.com/

Basically, the actual date the claims will be dedicated to the public at the time of grant is almost always unknown.

Greetings, Duncan -- and thanks for your riposte.

I mentioned amendments because they can affect the duration of the currency of one or more claims. A casual reader of the front cover might be led to assume that an apparently integral claim of the patent was still in existence.  And if a warning notice is in place, the reader still has to do his due diligence to see if the patent is still in force, so he hasn't gained anything.

Hi Jeremy

Thanks very much.

The amendment issue you raise is a good one, but exists whether or not the patent states the expiry date. 

Also, anyone who picks up a patent has to do a lot of due diligence before they know how it affects them - construction of the claims, infringement, validity, and so on.

Have I missed the point you're making?  (Sorry if so - and please do correct me.)

Regards

Duncan

Hi Erin-Michael

Thanks - this seems to me to be the easy way out for patent offices.

Why can't they republish the front page if the term is extended and have a simply worded disclaimer about lapse, withdrawal, etc.?

Cheers

Duncan

This is a great idea.  Clients ask me this all the time and it only serves to make patents more mystifying that they can't tell the time period over which it is effective.

Hi Duncan,

Thanks for comment on my blog. And you are right, it is the easy way out for patent offices.

My only point is that in almost every single case, even if an expected maximum life date is published on the cover, one will still need to check the file history to see if it is abandoned or not.

A newly issued patent in the US will expire 3.5 years after grant if the maintenance fees are not paid. The only way to check is in the file history. 

Even if the office publishes future 3.5, 7.5, 11.5 year dates and the legal maximum date and keeps track of any extensions due to drug approvals, it still can only tell me when the case is going to expire in one instance - only when in that window between 11.5 years and the legal maximum. Even then that assumes the Office would republish each application when it went abandoned to let the community know that it had not been renewed.

If a company is making investment decisions based on when a patent expires, they should likely be checking the file histories anyway. In the end, the work to keep track of and republish all of those patents, probably outweighs the societial benefit.

Thanks Erin-Michael

I see what you mean, but there's no need to republish each time a renewal fee is paid - in many other countries that would be every year.

What we are talking about is the maximum term of the patent, assuming all renewals are paid.

In actual practice, patents are handled in a triaged manner.  The due diligence proceeds by iterations of increasingly detailed analyses to test relevance to the task at hand. 

Patent term is one of the simple ways to test relevance - you won't infringe after this date.  In practice, companies handling large freedom to operate due diligences will proceed from simple analyses such as term and family members, through literal claim scope, non-literal claim scope (DOE in the US, etc), validity, and so on.

How can I learn a patent's expiry date?