Is it patent infringement to improve and innovate on the basis of others' patents? Or a partial quote.

Improvement on the basis of other people's patents depends on how to improve, and then analyze whether it is infringement. Let's take an example to illustrate that if patent A has four innovations of ABCD and protects it, if you find that the products made by ABCD alone are not good enough, adding new innovations to form ABCDE and launch the products will still be infringed. But if you find that innovation C in patent A is not important, you can use ABD to improve it, or change it to Abd. Then it does not constitute infringement. Infringement or not depends on whether the technology used in your product falls within the scope of the other party's claim, and has nothing to do with whether the other party sues.