I have a question concerning US reissue patent RE43748 E1 (based upon US 6787544 B2). The status in PAIR is "Patented Case", it is Continuation-in-part of application No. PCT/JP99/04429, filed on Aug. 18, 1999. No PTA/PTE. As far as I can see the application should be expired since August 18, 2019. So Google Patents

2019-08-18 Anticipated Expiration, Status: Expired - Lifetime

Fees: Window 11.5 Year, Status Closed, Fees Paid, Last Day to Pay 09/07/2016.

Is the application still alive or expired?

Best regards from Karlsruhe, Germany


1 Answer 1


First off, if you are being threatened with a legal action, you really need to consult with a lawyer. That said, I looked up RE43748 on the US Public Pair site. Select "Patent" and enter RE43748. It claims priority from PCT/JP99/04429 which has a filing date of 08-18-1999. There were no patent term adjustments so the patent should have expired by now.

So if you were selling or manufacturing a product in the United States before 08-18-2019, you might have infringed the patent. A US patent is not enforceable in any other country. In any case, I am not a lawyer so this isn't legal advice. As I said, if you are being threatened with a lawsuit, you really need to consult with an attorney and not rely on internet Q&A sites.

  • Thanks for your answer. My field of activity is patent documentation, so my question was more theoretical. Sometimes it's hard to tell if a US patent is still alive or not, e.g., US patent application 09/068,151, filed on 05/14/1998, PCT date is 03/02/1998, no PTA/PTE, but US Public PAIR status is "Patented Case" Commented Apr 24, 2020 at 5:01
  • Although Google Patents is fast and easy, for US patents, checking the US Public Pair is necessary to get authoritative results.
    – Eric S
    Commented Apr 24, 2020 at 14:24

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