Legal analysis: there is no problem with the validity of well-known trademarks. There is no accurate concept of the term of protection of well-known trademarks, because the validity period of a trademark after registration is 10 years, and even a well-known trademark needs to be renewed after 10 years.

Legal basis: Article 14 of the Trademark Law of People's Republic of China (PRC) shall, at the request of the parties concerned, identify well-known trademarks as facts that need to be identified in handling trademark cases. The following factors should be considered when identifying a well-known trademark: (1) the awareness of the trademark by the relevant public; (2) the term of use of the trademark; (3) the duration, degree and geographical scope of any publicity work of the trademark; (4) The record that the trademark is protected as a well-known trademark; (5) Other factors that make the trademark famous.