There is no clear legal provision on how long to conduct preliminary examination after patent acceptance. The law only stipulates that the publication time of a patent that has passed the preliminary examination is eighteen months from the date of application, and the substantive examination time is three years from the date of application according to the examination request put forward by the parties.
Legal objectivity:
Article 40 In the Patent Law, if the application for a patent for utility model or design is not found rejected after preliminary examination, the administrative department for patent in the State Council shall make a decision to grant the patent right for utility model or design, issue the corresponding patent certificate, and register and announce it at the same time. The patent right for utility model and the patent right for design shall take effect as of the date of announcement.