Prescription for instituting legal proceedings concerning the infringement of patent right is two years counted from the date on which the patentee or any interested party obtains or should have obtained knowledge of the infringing act. If the infringement still exists and the patent right is legal, even the patentee institutes legal proceedings over 2 years, the court shall accept the case. If the defendant is asked to stop the infringement, the imposed fine shall be counted backwards 2 years from the day the patentee institutes legal proceedings.