It has nothing to do with the expiration date. After the design and utility model are authorized, their technical contents will be made public, and the technical contents will be made public within 6-8 months after the invention application. These technical contents can be directly inquired through the network platform.
For example, China National Intellectual Property Administration's search platform /sipo2008/zljs/ can search all published patents or patent applications by keyword combination according to the technical problems or products you are concerned about.