What is the preemptive right of patent right?

The right of first use refers to the behavior that the non-patentee has manufactured the same product before the patent application date of the patentee, used the same method or made necessary preparations for manufacturing and using it, and continued to manufacture and use it only within the original scope after the patentee's application is authorized, which is not regarded as infringement of the patent right. The conditions for enjoying the right of first use are: (1) making necessary preparations for manufacture and use. Necessary preparation refers to the completion of product drawing design and process documents, the preparation of special equipment and molds, or the completion of sample trial production; (2) continue to manufacture and use only within the original scope. The original scope refers to the actual production output or production capacity of special production equipment prepared before the patent application. Manufacture and use beyond the original scope constitutes infringement of patent rights. (3) The pre-used product or method should be independently researched by the first user or obtained by legal means, not copied, stolen or obtained by other improper means from the patentee before the patent application date. (4) The prior obligee may not transfer the technology it has implemented, except that it is transferred together with its affiliated enterprises. The sale of products based on the right of first use is not regarded as infringement of patent rights.