In addition, from the perspective of patent application review, the application for a patent for invention needs to go through substantive review, that is, patentability review, which is more strict, while the application for a patent for utility model is only a formal review, which does not involve patentability review. In other words, as long as there are no errors (obvious errors) in the document, the patent for utility model will be granted. Judging from the examination cycle, the examination cycle of invention patent application is long, 3 or 5 years is normal, and the examination time of utility model patent application is short, ranging from a few months to a year and a half.
From the point of view of the stability of patent right, the invention is subject to substantive examination, so once the patent right is obtained, its right is relatively stable and not easy to be declared invalid, while the utility model is not subject to substantive examination, even if it is patented, its right is very unstable and easy to be declared invalid.
From the protection period, the protection period of the invention is 20 years, and the utility model is 10 year.
Most of the above are in accordance with China's patent law, while the foreign patent law system is different. For example, in the United States, there is no distinction between inventions and utility models, only inventions and designs plus a plant. Inventions actually include China's inventions and utility models, all of which have been substantially examined.