Second, if there is a patent right in advance, the heir is infringing. Unless the heir has evidence to prove that the patented technology has been implemented or prepared for the implementation of the patented technology before the patent application date, the "right of first use" can be used as a non-infringement defense.
Third, in order to avoid infringement, others can buy patents, pay for them, change product design and avoid patent barriers.
Fourth, there may be many ways to realize the same function, and they are different, so infringement can usually be avoided.
Fifth, more.