What is the date of invention?
The patent invalidity search attempts to locate prior art patents or nonpatent publications that predate a critical date that corresponds to the date of invention of the target patent. The date of invention can differ depending on whether a particular country’s patent system uses first-to-invent or first-to-file scheme. In a first-to-invent country such as the U.S., when an inventor conceives an invention and diligently reduces it to practice, the date of invention will be the date of conception. Thus, in a first-to-invent country where the inventor diligently reduced the invention to practice , a prior art search attempts to locate references that precede the date of conception. In a first-to-file country, the date of invention is deemed to be the date the patent application is filed. In such a country, a prior art search attempts to locate references that precede the date the patent application was filed. Note that even in a first-to-file country the date of invention will be the pat
