Invention patent examination is divided into three stages.
The first stage is the preliminary review, which takes about 3-6 months. After passing the preliminary review, a preliminary review notification will be issued.
The second stage is the substantive examination, which lasts for about 1-2 years (depending on the number of responses to examination opinions). After passing the preliminary examination, you can officially enter the substantive examination stage after paying the substantive examination fee.
The third stage is the authorization stage, that is, your patent passes the substantive examination and an authorization notice is issued. You can receive the invention patent certificate 2 months after you pay the authorization fee (certificate fee, annual fee) .
Therefore, the entire application process (assuming the patent is not rejected) takes between 1 and a half to 3 years.