After a patent application is granted a patent right, if the patentee wants to maintain the validity of the patent right, he/she must pay an annual patent fee to the Patent Office of the China National Intellectual Property Administration every year at the specified time (before the date corresponding to the application date). Otherwise, the Patent Office will consider that he/she has voluntarily abandoned the patent right he/she has obtained. In this way, any unit or individual can use their inventions and creations free of charge.