The identification code of the patent application date is 22, because the patent application date is the date of patent application, indicating the date of patent application, and the patent application number is the patent application number given by the patent application. Patent application numbers have a certain arrangement: after 2004, patent application numbers are 12 digits, 1 dot (. ) and a parity bit including four application year numbers and 65438+. The first four digits in the patent application number indicate the year number of the patent application, the fifth digit indicates the type of the patent application, and the 6th-12nd digit (* * * 7th digit) is the serial number of the application, indicating the relative order of accepting the patent application.