Legal analysis: Within three years from the date of filing, the patent administrative department of the State Council may, according to the request made by the applicant at any time, conduct substantive examination on the application. The request for substantive examination shall be filed within three years from the date of application, and the substantive examination fee shall be paid within this time limit. Because the examination procedure of invention patent is preliminary examination first, and then substantive examination, only after the preliminary examination is qualified can a request for substantive examination be submitted to the Patent Office within three years from the application date (priority date).
Legal basis: Article 35 of the Patent Law of People's Republic of China (PRC) * * * Within three years from the date of filing, the patent administration department of the State Council may examine the application in advance according to the request made by the applicant at any time; If the applicant fails to request substantive examination within the time limit without justifiable reasons, the application shall be deemed to have been withdrawn.