I filed a patent(provisional) a couple of months ago. The disclosure consist of two parts: 50% description of an underlying technology, and 50% a specific application of this technology. I haven't filed the claims yet. My initial plan is to file claims for the specific application of this technology (that is the real novelty), but not sure whether to claim for the technology itself as I'm aware of similar things, not exactly the same though. I thought to postpone this decision until I get proper advice. I guess I can always file narrow claims for the underlying technology, if that made any sense.

Now I want to file another patent for a different invention that shares the same underlying technology with the first one. The disclosure is again 50% underlying technology and 50% new application. My initial plan is the same as with the first one, in some months time I'll file claims for the specific invention but I'd like to leave open the possibility of claiming the underlying technology if that makes strategic sense.

My questions are, can the second patent claim priority of the first patent, based on the fact that the disclosure is 50% the same (the underlying technology), even if the inventions are very different? If I claim priority but then later on I don't file claims for the underlying technology would that priority claim be a problem? and finally, can priority claims be added or removed by the claimant after first filing?

1 Answer 1


You should get proper advice for your specific situation. This answer is a "how the system works" explanation, not a solution for your case.

If the second filing you are planning to do will also be a provisional application then it can not claim the benefit of the earlier filing. Provisonal applications stand alone and can not get priority from anything else. However there is no requirement for a one-to-one correspondence between provisonal and non-provisonal applications. Except in rare cases, provisionals are not literally "converted" to become a non-provisonal. Rather a distinct non-provisonal application is filed that claims the benefit of one or more provsional applications. And a single provsional can provide benefit to multiple non-provisionals.

You do not get in trouble for stating that a non-provisonal claims the benefit of a provisonal based on the subject matter of the provsional not being claimed in the provisional. It works the other way around. Claims in the non-provisonal that turn out to be fully supported by the provisonal get the benefit of the earlier date. Claims not fully supported do not get the benefit of the earlier date.

And finally, priority claims can be changed without any special consideration up to four months after the filing of the non-provisional application OR sixteen months after the provisional's filing date. If the non-provisional was filed, as many are, on the very last day, then these two times are the same.

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