Although the patent application process weeds out most fraudulent applications sometimes patents are granted to the wrong person by mistake. This may be the result of a misunderstanding or someone acting with a bad motive. In either case, inventors who feel that that a patent was granted incorrectly may bring an action in court to invalidate it.
A plaintiff who brings a trial for invalidation of the patent, if successful, will be able to invalidate the patent as if it never existed. Trademarks, utility models and design rights may also be invalidated in this way.
At the trial for invalidation, the plaintiff must show that the patent was granted improperly. This can include a variety of reasons, from the original patent being based on fraud or deceit to the patented invention already having been invented by someone else. If the trial declares the patent was improperly granted, the patent will be considered invalid retroactively, all the way back to when it was granted.
The JPO requires a representative from within Japan, such as an attorney, to conduct all procedures with the JPO. Having a local representative is especially important for complicated matters such as invalidating a patent. If you have any questions about patent law in Japan, please contact our office for a legal consultation.