How many patents are there in a patent? How to distinguish them?

There are three kinds of patents in China: invention, utility model and design. The object of an invention patent can be either a method or a product; The object of utility model can only be the product, which can only involve the improvement of product structure and function; The object of design protection is the appearance of the product. The invention patent has the longest protection period of 20 years and the highest stability, but the application requirements are relatively strict. The protection period of utility model and appearance patent is 10 year, and its stability is not as good as that of invention patent. In application, the type of application can be determined according to the market demand of the product, so as to achieve the balance between perfect protection and rapid authorization.