2. Log in to Intellectual Property Publishing House and use the "legal status inquiry" function to inquire whether the patent has expired.
3. Inquire whether the patent has expired in the invalid patent database of China officially released by Intellectual Property Press.
Methods of inquiring foreign invalid patents;
1. From the protection period, it can be inferred whether the patent naturally terminates as invalid due to the expiration of the protection period.
2. Determine the legal status by consulting the patent register of the national patent office.
3. You can directly go to the official websites of patent offices in various countries or the website of the European Patent Office for free inquiry and download the original text, or you can enter the inquiry through the related link "Major Foreign Intellectual Property Websites" on the website of China National Intellectual Property Administration.