Legal basis:
According to the provisions of the Patent Law: Article 11 After the patent right for invention and utility model is granted, no unit or individual may exploit its patent without the permission of the patentee, that is, it may not manufacture, use or sell its patented product or use its patented method for production and business purposes, except as provided for in Article 14 of this Law.
Article 63 Any of the following circumstances shall not be regarded as infringement of the patent right:
(1) After the patented product manufactured or imported by the patentee or manufactured or imported with the permission of the patentee or the product directly obtained according to the patented method is sold, the patentee uses, promises to sell or sells the product;
(2) Having manufactured the same product, used the same method or made necessary preparations for its manufacture and use before the patent application date, and continuing to manufacture and use it only within the original scope;
(3) Foreign means of transport temporarily passing through China's territorial waters and airspace use the relevant patents in their devices and equipment for their own needs in accordance with the agreements signed between their countries and China or international treaties to which they are both parties, or on the principle of reciprocity;
(four) the use of relevant patents for scientific research and experiments.
If the use or sale of a patented product that is not known to be manufactured or sold without the permission of the patentee or a product directly obtained by a patented method is used for production and business purposes, it shall not be liable for compensation if it can prove the legal source of the product.
Therefore, patent infringement can be defended without knowing it; Have normal purchase channels, can prove its legal source, and need not bear civil liability for compensation.