and Mathew Evans
● a lower current electricity
● a small carbonized filament, and
● an improved vacuum inside the
● The invention is new (i.e., novel),
● Non-obvious (i.e., not trivial or common
● Capable of Industrial Application
● An improvement made to an existing patented device.
● Improvements have to be new and nonobvious.
● The new improved product must be exceptionally better
than the original.
Types of Improvement Patents
Addition inventions - requires that new
components be added to the existing
Substitution inventions - can be issued to
devices that have had major component or
material changes which result in a better
Relationship Between Basic and Improvement
● Whether the improvement patent can be practiced without
infringing the basic patent?
● Whether the differences between the improvement and the
disclosure of the basic patent are obvious at the time the
invention was made.
● In considering the patentability of an improvement
over a prior patent, compare the complete disclosure of
the prior patent to determine what it would teach one
skilled in the art and then compare that teaching with the
● In evaluating infringement, focus on the claims of the
prior patent and compare them with the improvements.
● The analysis between a basic patent and an improvement
patent, therefore, involves an initial inquiry as to whether
the issue is one of patentability over the basic patent or
infringement of the basic patent.
● The factual determinations and legal evaluations are
different depending upon which type of evaluation is being
● In evaluating patentability in comparing a basic patent with
an improvement patent, not only the technology involved
but also the identity of the inventors can be important.
● If there is common ownership or if a license has been
granted by the owner of the basic patent to the owner of the
improvement, infringement would not be a problem.