In order to be eligible for patent protection, United States patent law requires that an invention be:

1. New or Novel: The invention must be demonstrably different from publicly available ideas, inventions, or products (so-called "prior art"). This does not mean that every aspect of an invention must be novel. For example, new uses of known processes, machines, compositions of matter and materials are patentable. Incremental improvements on known processes may also be patentable.
2. Useful: The invention must have some application or utility or be an improvement over existing products and/or techniques.
3. Non-Obvious: The invention cannot be obvious to a person of "ordinary skill" in the field; non-obviousness usually is demonstrated by showing that practicing the invention yields surprising, unexpected results.