Patentability requirements – Useful Requirement

In order to obtain a patent on an idea, that idea must be “useful.”   In other words, the idea must have some useful purpose.  The “useful” patent requirement is a low standard and typically easy to meet.  Typical exceptions to the useful requirement occur in perpetual motion machines, which do not serve a typical “useful” purpose and chemical compounds that have no known use.  Useful rejections are rarely encountered when filing a patent application.