Legal analysis: The method of determining the patent application date is as follows: 1. Directly submit the patent application documents that meet the requirements of the specification to the China National Intellectual Property Administration Patent Office and its established agency, and the date when the accepting department receives the patent application documents shall be the application date; 2. The postmark date of qualified patent application documents shall be the application date through the post office.
Legal basis: Article 28 of the Patent Law of People's Republic of China (PRC). The date when the patent administrative department of the State Council receives the patent application documents is the filing date. If the application documents are mailed, the postmark date of mailing shall be the application date.