There is no clear legal provision on how long it takes for a patent to be issued from application. From application to certification, there are five stages: acceptance, preliminary examination, publication, actual examination and authorization. The law only stipulates that the time for publishing the preliminary examination is eighteen months from the date of application, and the time for applying for substantive examination is three years from the date of application. If no reason for rejection is found after substantive examination, a certificate may be issued.