It is very difficult to invent Patent examiners and take out a number of cases from the patent pool.

According to the communication with examiners, the retrieved documents are generally reduced to dozens or hundreds by restrictions, and then browsed, and some obviously irrelevant ones are eliminated for further research. It usually takes half a day to search. Of course, sometimes the examiner will work overtime. For foreign language documents that are difficult to search or have many documents, the search time may reach three days.