What is the substantive examination of national invention patents?

The substantive examination of the invention patent refers to the examination of the novelty, creativity, practicality and other substantive contents of the invention for which the patent is applied by the State Patent Office. Legal basis: Article 35 of the Patent Law of People's Republic of China (PRC). Within three years from the date of filing, the administrative department for patent in the State Council may, upon the request of the applicant at any time, make a substantive examination of the application. If the applicant fails to request substantive examination within the time limit without justifiable reasons, the application shall be deemed to have been withdrawn. The patent administrative department of the State Council may, when it deems it necessary, examine the application for a patent for invention on its own. For the substantive examination that has been applied for, some can take the form of written examination, that is, through the statement of the application materials to understand the relevant situation and conduct the examination, but some substantive examinations need to be verified on the spot to confirm the real situation.