U.S. patents are divided into two types: invention patents and appearance patents. It is divided into large and small entity enterprises, with an invention patent protection of RMB 5.5 (for a large entity) and RMB 50,000 (for a small entity) for 20 years. Design protection for 14 years, RMB 27,000 (large entity), RMB 22,000 (small entity). U.S. patents are subject to substantive examination, and there are uncertain factors in the later period, such as defense, corrections, and additional fees