2. The patent application accepted in the preliminary examination stage will automatically enter the preliminary examination stage if the application fee is paid in accordance with the regulations. Before the preliminary examination, the application for a patent for invention must be examined in secrecy, and if confidentiality is necessary, it shall be handled in accordance with the confidentiality procedures. During the preliminary examination, it is necessary to examine whether there are obvious deficiencies in the application, mainly including whether the contents of the examination fall within the scope of the patent law of People's Republic of China (PRC), whether the obviously lacking technical contents cannot constitute a technical scheme, whether there is a lack of oneness, whether the application documents are complete and whether the format meets the requirements;