Looks for unexpired patents with claims that may bar you from making, using, or selling a product. Patent infringement is “the unauthorized practicing of a patented invention”. As with a patentability search, an infringement search is concerned with novelty and prior art, but for different reasons. An infringement search is carried out specifically with the idea of determining whether or you can make, use, or sell an invention “without infringing the unexpired patents of others”. The infringement search is intended “to insure that the subject matter you are acquiring is not covered by other patents”. An infringement search is also sometimes carried out as part of an effort to prevent others from making, using, or selling the invention claimed in your patent.