In a scenario where:

a. NP (of invention "1001") is first filed in a foreign country (non-US Country, on 1 Jan 2017) and then a PCT is filed(on 31 Dec 2017), when will patent life begin for invention "1001" in The US?

b. If NP was filed in The USA itself (of invention "1001", on 1 Jan 2017) and then the application is filed for PCT (on 31-Dec-2017), when does patent life for invention "1001" begin in this case?

As per my understanding,

the normal flow till national phase is this:

Provisional/NonProv -12months->PCT-6months->WO Publication->12 months -> national phase

and, normal NP flow is this:

NP -> 18 months -> Publication(open for objection)-> 18 months ->Patent granted

My scenario then becomes:

a. If my NP was 1st filed in a foreign Country(Non-US), what would be 1st filing date considered for patent life - NP filed in foreign Country or NP filed in the US


b. If my NP was 1st filed in US , then PCT was applied, - will it re-enter a national phase and from that moment wait for 18 months for US publication of my invention? And when will patent lifecycle begin in this case?

Also, my understanding of royalty and patent life is that:

20 years life of an invention begins from the date of it's non-provisional application, but it's royality period begins from its first filing date of PPA, equivalent foreign PPA, given that the PPA/equivalent PPA later gets granted.

Please assist me.

  • What do you mean by "royalty period"? It's not a term I'm familiar with. Do you mean the period over which a patent may be enforced?
    – Maca
    Commented Jan 17, 2017 at 9:01
  • I mean from the time one is eligible to receive any infringement royalty from an infringer, after patent grant.
    – KSR
    Commented Jan 17, 2017 at 9:21

2 Answers 2


I agree with chempatent1981's answer on the expiry. I shall therefore focus on the when damages might be due.

You have used the term "royalty period". However, as far as I know, that is not really a widely used term. Perhaps a more common description would be the period during which actionable infringement may occur.

There are three periods in which "infringing acts" may occur (whether or not they are actionable), which in reverse chronological order are:

  1. After issuance but before expiry.
  2. After filing and publication but before issuance and expiry.
  3. After filing but before publication, issuance and expiry.

I shall touch on each in turn.

1. Infringement after issuance

In the US, the starting point is that anybody who makes, uses, offers to sell, or sells a patented invention infringes the patent (and thus may be liable for damages) (35 USC § 271(a)). A patented invention is an invention claimed in a patent (which is, by definition, issued).

Thus, any acts between issuance of a patent until it expires may give rise to damages.

2. After filing and publication, but before issuance

35 USC § 271(a) requires a patented invention. Before issuance, there is no patented invention. Any "infringing acts" are therefore not infringement, and therefore do not give rise to damages under 35 USC § 271.

However, 35 USC § 154(d) provides for provisional rights. To be clear, provisional rights have nothing to do with a provisional application (and in fact can only ever apply to a non-provisional application, since provisional application are not published).

Provisional rights arise from the date of publication (of either a US non-provisional application or an English version of a PCT application designating the US) until a patent is issued (35 USC § 154(d)(1)).

There are two key prerequisites for provisional rights:

  • the infringer had actual notice of the publication (35 USC § 154(d)(1)(B)); and

  • the invention claimed in the patent is substantially identical to the patent claimed in the published patent application (35 USC § 154(d)(2)).

If this occurs, an infringer will be liable for "a reasonable royalty".

3. After filing but before publication and issuance

There are no rights in this period. 35 USC § 271(a) does not apply because there is no patented invention. 35 USC 154(d) does not apply because there is no publication.

  • so, considering case 3: Had inventor filed for a PPA and then filed for NP, the inventor was eligible to receive infringement damages, after filing PPA (and before publication - publication of NP claiming PPA); given that the infringer's invention is identical to patent claimed? Also, inventor would be eligible for infringement damages only after patent grant for the infringement which occurred after PPA was filed but not yet published(post-NP filing)?
    – KSR
    Commented Jan 18, 2017 at 4:11
  • @reindeer Not quite. There are no damages for acts performed before publication. Since a provisional is not published (at least before a non-provisional is published), it doesn't matter what a provisional discloses: a provisional can never give rise to any kind of damages.
    – Maca
    Commented Jan 18, 2017 at 4:15
  • so, If I filed my PPA on Jan-01-2017, filed for NP on Dec-31-2017 and had my NP published on May-30-2018, and an infringer infringes my application on April-01-2018. On Dec-31-2019 I have my patent granted. Will I then be eligible for infringement damage, after 31-Dec-2019 for the infrigement made on April-01-2018.
    – KSR
    Commented Jan 18, 2017 at 5:14
  • @reindeer No. You may have provisional rights for acts that occur from publication (30 May 2018) until issuance (31 Dec 2019), then it would be regular infringement for acts that occur after issuance (from 31 Dec 2019 until expiry). The act on 1 Apr 2018 is before publication, and therefore you cannot do anything about it.
    – Maca
    Commented Jan 18, 2017 at 5:17
  • then what is the use of provisional from date priority perspective? I understand that for PPA, I do not have to have a test scenario filed for my invention, neither do I have to have claims written. So can I conclude that to file an application without any test cases and without getting into invention claims and too much description, I file a PPA, so that 12 months from then I can further file for PCT or NP, but that still incurs me no benefit from receiving infringement damage till NP application publishing date or WO publishing date?
    – KSR
    Commented Jan 18, 2017 at 5:29

a. The US filing date is the PCT filing date. You can find this stated clearly in this useful web page http://www.bpmlegal.com/howtoterm.html (1st asterisk). 20 year life time starts from the filing date, so the clock starts ticking at 31.12.2017.

b. You have not specified if you are using the US filing as a priority or as normal US filing. You have two options: You can use the US filing of 01.01.2017 to start a normal US prosecution and at the SAME TIME use it as priority to file a PCT (at 31.12.2017). This is of course not very smart, because the US patent will expire on 01.01.2037 while the PCT-stemming national patents will have a filing date of 31.12.2017, hence they will expire 31.12.2037. Can you see the 20+1 game here? OR you can use the US filing (US provisional this time) as a priority document and file a PCT application on 31.12.2017. The provisional will be abandoned, after surving its purpose. You can use the PCT application for US entry and normal national patent. The only thing you gain this way is establishing an earlier date, even though, probably, your invention has not been fully developed. Is it more clear now?

The publication date is only making it more complex, leave it outside for the purpose of understanding how filing and expiration dates work. But if you want to clarify this further, I'll be happy to try and help you!

I am not familiar with royalties, but I am sure someone will fill the gap here.

  • do you mean filing date when you mention 'filling date'?
    – KSR
    Commented Jan 17, 2017 at 7:10
  • patents.stackexchange.com/a/17059/18033 This seems to say different, saying the first filing date counts for the 20yrs. I'm not sure which is right though.
    – user18033
    Commented Jan 17, 2017 at 7:17
  • also, my scenario 'a.' is specific about a NP filed in a foreign Country(non-US country), then how can filing date of NP and US filing date be same? my understanding is this: Provisional/NonProv -12months->PCT-6months->WO Publication->12 months -> national phase;
    – KSR
    Commented Jan 17, 2017 at 7:26
  • It's only after 30 months of 1st filing date, that the application enters national phase, and from there it is considered a NP and it follows the same NP cycle phase: US NP -> 18 months -> Publication(open for objection)-> 18 months ->Patent granted ; My question is, patent lifecycle in this case is granted from NP filed internationally or from US NP filing date.
    – KSR
    Commented Jan 17, 2017 at 7:26
  • Sorry for mispelling, I never noticed that until today (not native english speaker obviously). I alse changed the answer to scenario b, I hope I explained it better now. Commented Jan 17, 2017 at 9:10

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