Brief Notes

US Patent Marking


This brief note is not legal advice and is for educational purposes only.
Congratulations! – you’ve got an issued patent with a patent number and are now wondering what to do with the patent number, or how to use it.


The grant of a patent now affords you the legal right to do such things as go after infringers, license the patent rather than an application or technology, sell the patent, etc.
If you want to sue someone for infringing your patent then notice must be given. Suits for patent infringement are normally filed under 35 USC § 287 – Limitation on damages and other remedies; marking and notice, which states in part “(a) Patentees, and persons making, offering for sale, or selling within the United States any patented article for or under them, or importing any patented article into the United States, may give notice to the public that the same is patented, either by fixing thereon the word “patent” or the abbreviation “pat.”, together with the number of the patent, or by fixing thereon the word “patent” or the abbreviation “pat.” together with an address of a posting on the Internet, accessible to the public without charge for accessing the address, that associates the patented article with the number of the patent, or when, from the character of the article, this cannot be done, by fixing to it, or to the package wherein one or more of them is contained, a label containing a like notice. In the event of failure so to mark, no damages shall be recovered by the patentee in any action for infringement, except on proof that the infringer was notified of the infringement and continued to infringe thereafter, in which event damages may be recovered only for infringement occurring after such notice. Filing of an action for infringement shall constitute such notice.” (Emphases added.)
So, either mark the product itself with the patent number or provide a web link where someone can look up the patent number. If the product cannot be marked, for example it’s too small to read or would affect the functionality of the product (e.g. a ball bearing) then put the notice, either patent number or web address in the literature or package that ships with the product.
If you fail to mark in this way, notice can be given by filing the infringement lawsuit. Prior notice is generally better and this can also be given by actual notice where, for example, a letter is sent to the alleged infringer (caution is advised here). There is also constructive notice which is where you have marked the product or package as noted above (that is you have not contacted the alleged infringer but you have put the public on notice of your rights).


By marking a product covered by your patent you preserve the right to sue for patent infringement. If your patent is to a method rather than a product – contact an attorney as this can get complicated. Contact an attorney for more details about marking and keeping your patent maintained and in force.

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