legal ground
patent law of the people's republic of china
Article 67
In a patent infringement dispute, if the accused infringer has evidence to prove that the technology or design he implemented belongs to the existing technology or design, it does not constitute patent infringement.
Article 77
Anyone who uses, promises to sell or sells an infringing patented product for the purpose of production and operation without knowing that it was manufactured and sold without the permission of the patentee shall not be liable for compensation if he can prove the legal source of the product.
Rule 84 of the Implementing Rules of the Patent Law
The following acts belong to the act of counterfeiting patents as stipulated in Article 63 of the Patent Law:
(1) Marking a patent mark on a product or its packaging that has not been granted a patent right, and continuing to mark the patent mark on the product or its packaging after the patent right is declared invalid or terminated, or marking the patent number of others on the product or its packaging without permission;
(2) selling the products mentioned in item (1);
(five) other acts of confusing people and mistaking a technology or design that has not been granted a patent right for a patented technology or design.