When a patent applicant submits a patent application, the Patent Office will give the application an application number. The three patent application numbers consist of 12 digits, arranged by year, such as 200310100002.x. In the application number, the first to fourth digits indicate the year when the patent application was accepted, and the fifth digit indicates the type of patent application: 1- invention, X. All patent specifications are composed of 7 digits, which are arranged in turn according to their respective serial numbers and accumulated year by year. The starting number is: the publication number of invention patent application starts from CN 103000 1A, the examination number of invention patent application starts from CN 100300 1B, the announcement number of utility model application starts from CN203000 1U, and the announcement number of design application starts from cn303. The first digit indicates the type of patent right: 1- invention, 2- utility model and 3- design. Followed by the legal status code: A and C respectively represent the announcement number of invention patent and the announcement number of invention patent authorization, Y represents the announcement number of utility model patent authorization, and D represents the announcement number of design patent authorization. The patent number is given when the patent certificate is issued, and the numbering system is ZL before the application number, such as ZL2003 10 100002. If you look up foreign patents, you usually use the 7-digit public (approval \ announcement) number, that is, country code (2 digits)+sequence number (7 digits)+legal status code (1 digit). For example, U.S. Pat.No. US5489846A. Therefore, if the fifth digit is 1, it means that the patent is an invention patent. If it is 2, it means that the patent is a utility model patent.