What is the duration of patent protection of intellectual property rights?

The term of the invention patent right is 20 years, and the term of the utility model patent right and the design patent right is 10 years, both counting from the date of application. The starting point of the patent protection period is not the patent announcement date, but the patent announcement date is the starting point for the patentee to obtain the patent right. The filing date of all kinds of patents is earlier than the announcement date, which means that the patent protection period enjoyed by the invention patentee is less than 20 years, and the patent protection period enjoyed by the utility model patentee and the design patentee is less than 10 years. For the patentee, the patent that exceeds the protection period becomes public technology, and everyone can use it for free. This patent has no selling point in the commodity market. Therefore, we should pay attention to the application date when purchasing patents, which will affect the consideration of patent transfer. It should also be noted that China's patent law stipulates that the transfer of patent application right or patent right shall take effect from the date of registration. Therefore, the patent "buyer" should remember to register the patent transfer with the relevant departments in China National Intellectual Property Administration to prevent others from infringing and ensure the maximization of his patent right.