I still can't able to understand how priority date works.

Let's say I filed a provisional patent in Jan 2019. That specification contains nearly 95% of the real invention.

In Jun 2019, I filed one more provisional patent, it adds another 3% of the invention. We are at 98% now.

Finally, I file a non-provisional in Dec 2019 and it contains, all 100% of the invention.

Now when claiming priority, I would obviously go for the Jan 2019 date. But what happens to the 3% content disclosed in Jun 2019 and 2% content disclosed in Dec 2019. Just to be clear, these 5% of the content will be claimed in claims.

Do they all have Jan 2019 date as priority?


In the first sentence of the non-provisional you claim priority to both of the provisionals. During the prosecution of the application and any divisionals or continuations you will have specific claims that will, most probably, meet with rejections based on "prior art" cited by the examiner. The examiner initially views anything prior to your non-provisional filing date as legitimate prior art. Say one of the references was dated after one of your provisionals. This is when it becomes relevant that you filed the provisional at all.

It will be your job to show, in your response to the rejection, that the relevant information/teaching that was contained in the cited reference was sufficiently covered in your provisional. If so, the cited reference is excluded as a prior art.

  • Thanks for the neat explanation :-) – Giri Jul 12 at 19:36
  • Can you fix the typo? prosection => prosecution – Giri 2 days ago

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