Legal analysis: The time to request a patent invalidation is any time after the patent is granted.
Legal basis: "Patent Law of the People's Republic of China" Article 45 From the date when the patent administration department of the State Council announces the grant of a patent right, any unit or individual believes that the grant of the patent right is inappropriate. If it complies with the relevant provisions of this Law, it may request the Patent Reexamination Board to declare the patent right invalid.