Legal analysis: The Patent Reexamination Board shall send a copy of the request for invalidation of the patent right and relevant documents to the patentee, asking him to state his opinions within a specified time limit. Therefore, when the patent is invalid, the time limit for the patentee to provide evidence should be based on the requirements of the Patent Reexamination Board.
legal basis: article 68 of the detailed rules for the implementation of the patent law of the people's Republic of China, the patent reexamination board shall send a copy of the request for invalidation of the patent right and relevant documents to the patentee, requesting him to state his opinions within a specified time limit. The patentee and the claimant for invalidation shall reply to the notice of transferring documents or the notice of examining the request for invalidation issued by the Patent Reexamination Board within a specified time limit; Failure to reply within the time limit shall not affect the trial of the Patent Reexamination Board.