There are a number of requirements that must be met for an
invention to be patentable. The invention must be novel (unique)
and nonobvious (i.e., a person skilled in the field of the
invention would not have found the invention obvious based on the
existing knowledge in the field). In addition, the patent
application must meet other requirements, including written
description (the application must contain a detailed, clear, and
definite written description of the invention) and enablement (the
application must describe how to make and use the invention). If
the patent application satisfies all of the requirements, a patent
is issued.
A third party can challenge an issued patent on several
different grounds, either in litigation or in the Patent and
Trademark Office's Patent Trial and Appeal Board (PTAB). If the
challenge is successful, some or all of the patent's claims
will be invalidated. If only some of the claims are invalidated,
those claims will be canceled
