Can anyone tell me when the 5971475 patent expires?

2 Answers 2


The patent issued on 10/26/99. The patent was filed on 12/4/97, but has a priority date of 12/5/96 due to the benefit of prior filed Provisional Application Ser. No. 60/032,110.

Based on 2701 Patent Term


this patent falls under the "on or after 6/8/95 rule" which is 20 years from the priority date. So that would be 12/5/16.

If the priority date had been prior to 6/8/95, then its expiration would have been the later of the 20 years from the priority date or 17 years from the date of issuance. So this would be the later of 12/5/16 or 10/26/16 so would still end up being 12/5/16 in this situation.

There are other reasons the patent could expire, such as not paying maintenance fees, but this patent appears to have had its maintenance fees paid in a timely manner (according to Google Patents "legal events" section).

George, is there something tricky about this patent or its history? You know this stuff much better than I so I'm sure I'm missing something.

  • Is that middle-endian date format?
    – TRiG
    Mar 18, 2014 at 22:18
  • The 20 years is measured from the oldest non-provisional filing date.
    – George White
    Mar 18, 2014 at 23:55
  • Thanks George. I did notice in the following link: uspto.gov/web/offices/pac/mpep/mpep-9015-appx-l.html#d0e302921 where section 35 U.S.C. 119(e) says that a provisional patent application CAN be used for the priority date IF a non-provisional patent application is filed within 12 months AND it contains or is amended to contain a specific reference to the provisional application. The nearly one year to the day difference between the provisional application and the non-provisional application looks like they intentionally did this to keep the patent private for as long as possible.
    – user4028
    Mar 26, 2014 at 3:08

The expiry date for the Patent US5971475A is 2017-12-04


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