The field of the invention is the field of art to which the claimed invention pertains. If a patent search has identified the classification (class and subclass) of the invention, then the subclass definition may be paraphrased. This section may also be titled "Technical Field." The statement of the technical field of the invention is placed in the Background of the Invention section of a U.S. patent application.
MPEP 608.01(c) - Background of the Invention