Our country’s patent drafting does not advocate the use of functional qualifications, so according to the rules, it is better to use structural qualifications. Functional limitation can only be used when it is difficult to define by structure. However, this functional limitation must be fully supported.
In short, generally speaking, the functional scope may be larger. Is it good or bad to be larger? The good thing is that the scope of protection may be wider, but the bad thing is that it may not be supported by the instructions and the rights are unstable.