Legal Definitions - prior-use bar

The prior-use bar, more formally known as the prior commercial use defense in U.S. patent law, is a legal principle that protects individuals or entities who have been commercially using an invention *before* someone else files a patent application for that same invention. It allows the prior user to continue their specific commercial use of the invention without being found to infringe the later-granted patent.

This defense is personal to the prior user and does not invalidate the patent for others. Its purpose is to protect established businesses or individuals who independently developed and used an invention in good faith before someone else patented it, preventing a patent holder from stopping a long-standing, independent commercial activity.

• Example 1: Manufacturing Process

  Imagine a company, InnovateTech Inc., that has been using a unique, proprietary method to cure composite materials for their aerospace components since 2010. They kept this process a trade secret. In 2015, another company, AeroPatent Corp., independently developed and patented a very similar curing method.

  If AeroPatent Corp. later attempts to sue InnovateTech Inc. for patent infringement, InnovateTech Inc. can invoke the prior-use bar. Because they were commercially using the method for several years *before* AeroPatent Corp. filed its patent application, InnovateTech Inc. can continue using their specific curing process without infringing AeroPatent Corp.'s patent.

• Example 2: Software Algorithm

  Consider DataStream Solutions, a software company that developed and implemented a novel data compression algorithm in their internal server infrastructure in 2018 to optimize storage. They never sought a patent for it. In 2021, CompresSoft Inc. obtained a patent for a nearly identical data compression algorithm.

  If CompresSoft Inc. discovers DataStream Solutions' use and attempts to assert their patent rights, DataStream Solutions can raise the prior-use bar. Their established commercial use of the algorithm *before* CompresSoft Inc.'s patent filing date allows them to continue using their existing system without infringing CompresSoft Inc.'s patent.

• Example 3: Business Method

  Suppose Local Eats Delivery started a unique subscription service in 2017 where customers pay a monthly fee for unlimited food deliveries from partner restaurants within a specific radius. In 2020, Global Grub Holdings patented a very similar subscription-based food delivery business model.

  Should Global Grub Holdings try to stop Local Eats Delivery from operating, Local Eats Delivery could assert the prior-use bar. Their continuous commercial operation of the subscription service *before* Global Grub Holdings filed its patent application means they can continue offering their service without infringing Global Grub Holdings' patent.