Tell the company's patent number directly, and you can search through Zhifuzi patent/tools/pteach.html.
Check the relevant patents, this can prove it.
If you need a formal patent legal document, you can ask China National Intellectual Property Administration to issue a copy of the patent register.
Download and fill in the request for copying documents in the "Service Area and Form Download" on the left side of the homepage of China National Intellectual Property Administration website, and send it by registered mail to the issuing room of the preliminary examination process department of China National Intellectual Property Administration. At present, this program is free.
PS: The patent certificate can only prove the legal status of the patent on the date of authorization, and the subsequent legal status shall be subject to that recorded in the patent register.
Extended data:
The format and content of the copy of the patent certificate and the original patent certificate are actually the same, both of which are composed of the first page of the certificate and the patent brochure. The only difference is that the copy of the patent certificate is manually stamped with the seal of "copy" in the upper right corner of the first page of the certificate.
Patent certificates are issued only once. If it is lost, China National Intellectual Property Administration will not reissue it. If the patent is changed, transferred or mortgaged, it will not be reflected in the patent certificate.
Generally speaking, all the information of a patent, such as the relevant information of the patentee, whether the state of the patent has changed, whether the patent has been declared invalid, etc. , will be recorded in this register. From a legal point of view, when granting a patent right, the contents of the patent register are consistent with those recorded in the patent certificate and have the same legal effect.
Generally speaking, patent-related documents can only be downloaded by the patent licensor himself by logging in his own account to apply for patent-related secret documents. Basically, except downloading patent documents in patent retrieval software, nothing else is allowed. This is also for patent secrecy. Patent certificate is the most important document for the use of patent right, and it needs to be kept by the patentee himself.
References:
Baidu Encyclopedia Patent Certificate