Owens Corning v. Fast Felt (Fed. Cir. 2017) illustrates an example of how the broadest reasonable interpretation (BRI) standard increases the chances that an obviousness argument could successfully invalidate a patent claim during a post grant patent review proceeding; and make it more difficult to overcome an obviousness rejection during patent prosecution. It also illustrates how broadening a claimed invention’s field of use could be detrimental to the claim’s validity and make it harder to overcome an obviousness rejection.