There is a temporary protection system in the patent law:
After the publication of an application for a patent for invention, if the applicant knows that someone has implemented the invention for which he applied for a patent, he can first send a notice to the other party stating that the invention has been patented, and has the right to ask the user to pay an appropriate implementation fee after warning.
If the applicant withdraws the application after the publication of the patent application, or if it is rejected after substantive examination, the applicant loses the right to request the payment of appropriate fees.
If it is used after the date of publication and before the date of authorization, it does not constitute patent infringement. Since the patent right has not been obtained, there is no infringement, and the applicant only enjoys the right to claim appropriate expenses.
To put it simply, patents should be made public first, then examined and then authorized. There is no infringement without authorization, but the applicant can ask for the payment of patent royalties, which must be paid after the patent is authorized.
Temporary protection lasts until authorized. After authorization, it is patent protection. If rejected, you can use it for free.
So,
The time of patent acquisition and the date of publication are not the same day.