It depends on what time period left to bring the payment up to date that you are talking about. For the remainder of the question I will refer to the 4 year maintenance period in discussion, but the same analysis will apply in 6 month periods to the 8 and 12 year maintenance payments.
If the payment is made within the 3 year to 3 year 6 month period, a surcharge IS NOT due with the payment and the patent is still in force. For this period, the infringer would not have any rights to the use of the patented invention and you would be able to enforce the patent against the infringer.
If the payment is made after 3 years 6 months and at the latest on the 4 year anniversary, a surcharge IS due with the payment and the patent is still in force. For this period, the infringer would not have any rights to the use of the patented invention and you would be able to enforce the patent against the infringer.
If you are attempting to pay the maintenance fee after the 4 year period, you would need to petition the director of the USPTO, have the reason for nonpayment be unavoidable or unintentional, and you would need to pay the surcharge as well as the maintenance fee. In this case, if the infringement began after the expiration of the 4 year period but before the late payment was accepted, the infringer would have intervening rights and would be able to continue the patented invention in the way they did during the period.
Answering of your question is merely general advice and does not constitute legal advice. None of the statements or implications made by this answer creates an attorney-client relationship with the attorney answering the question. The statements made in this answer are not to be solely relied upon and you should meet with a competent attorney to discuss any concerns you may have regarding this answer.
If a patent owner does not pay the maintenance fees on a patent, they may lose their rights as the owner of the patent. Generally, a U.S. patent is good for 20 years from the filing date of the patent. To maintain the patent, the owner must pay “maintenance fees” to the U.S. Patent & Trademark Office at intervals of 3.5 years, 7.5 years and 11.5 years after the issue date of the patent. A patent that expires for failure of payment of the maintenance fees will expire on the 4th year, 8th year, or 12th year anniversary date that the patent was granted.
If the maintenance fees are not paid, the patent will lapse and cannot be enforced, with two exceptions: patents for design or plant patents have no maintenance fees. If a patent has lapsed due to the owner’s failure to pay maintenance fees, the patent may still be revived for up to two years after the lapse, if the delay in paying the fees was unintentional. For later revivals, the USPTO requires proof that the delay in paying the fees was unavoidable, a very high standard to meet.
Third parties, who begin practicing the invention while the patent has lapsed due to the patentee’s failure to pay the required maintenance fees, are permitted to acquire “intervening rights,” an equitable doctrine that permits continued use of the invention even if the patent owner obtains the reinstated patent.
This is a fact specific question you should contact a patent attorney immediately to determine what you can do.
Does this infringer have rights to the patent? No, the patent is still the property of the original patent owner, it does not transfer to the infringer. But if the patent expired anyone can practice the invention.
Will he prevail if he is sued for infringing? If the patent has expired and cannot be revived, the patent holder will not be able to sue for infringement because there is no more patent, the case will be dismissed.
It depends on when the fee was due. There may be no loss of rights or there may be "intervening rights". So, you need to pay at once if you want to minimize intervening rights. A registered patent attorney anywhere in the country can handle this for you easily.
I am not your lawyer and you are not my client. Free advice here is without recourse and any reliance thereupon is at your sole risk. This is done without compensation as a free public service. I am licensed in IL, MO, TX and I am a Reg. Pat. Atty. so advice in any other jurisdiction is strictly general advice and should be confirmed with an attorney licensed in that jurisdiction.
If your maintenance fee is not paid, then the patent is abandoned and not enforceable. Therefore if the patent is infringed during the time when it is abandoned, there likely is no recourse. Under no circumstances, however, does infringer have rights to the patent itself.
Short Answer: It depends. Failure to pay maintenance fees can result in abandonment of the patent, in which case, you can't succeed in an infringement suit because there can be no infringement of an abandoned patent. On the other hand, if the infringement began before the abandonment, then there can be a successful lawsuit for infringement for the period when the patent was "alive." Good Luck.