How to inquire the date of publication after patent announcement?

The date of publication refers to the date when the patent department receives the application for a patent for invention, which is considered to be in conformity with the provisions of the Patent Law after preliminary examination, and will be published after 18 months from the date of application. Can be announced as soon as possible at the request of the applicant. Public days are for invention patents, but there are no public days for utility models and designs. The date of authorization announcement refers to the date when the patent department makes a decision to grant a patent right, issues a patent certificate and registers the announcement at the same time. The patent right shall take effect as of the date of announcement. The invention patent was published after preliminary examination without substantive examination. During the period from the date of filing to the date of publication, the applicant may change his patent application, but he has no patent right yet, and can only obtain the patent right after substantive examination and authorization announcement. Utility models and designs do not need substantive examination, but are granted patent rights and announced after preliminary examination, so there is no concept of public day.