Patent invalidity is when a prior art surfaced similar to the invention being applied for patent. Patent invalidity does not automatically happen if there are patents similar to the invention; however it is difficult to obtain a patent if there are identical patents to their invention.

Patent search could help prevent patent invalidity of an invention. Patent invalidity could be avoided by doing a thorough patent search in the database records of prior patents and publications of Patent Search Office. It is the patent counsel’s job to compare a collection of prior patents, printed publications, journals or other technical articles with the invention. But before doing so, he or she must examine each of these “references” in order to ensure that they are valid. Finally, the patent opinion discloses the likelihood that a patent will be granted on the proposed invention.This is where the patent counsel proceeds to apply for a patent.