How to apply the principle of redundant designation in patent infringement cases?

the principle of redundant designation, also known as the principle of unnecessary technical features, is one of the principles for determining patent infringement in China. It refers to the principle that the court divides the technical features of the claim into necessary technical features and unnecessary technical features in patent infringement litigation, and determines the scope of patent protection only by the necessary technical features in the claim when ignoring the unnecessary technical features (redundant features), and determines whether the accused infringing object falls within the scope of protection of the claim. How to apply the principle of redundant designation in patent infringement cases, but the court cannot use this principle lightly in patent infringement cases. All the technical features written in the independent claim are necessary technical features and should be included in the comparison of technical features, and the so-called principle of redundant designation cannot be applied rashly. For the substantial waiver or restriction made by the right holder in the patent authorization and confirmation procedure, it should be forbidden to go back on our word in the infringement lawsuit, and the relevant technical content should not be included in the scope of protection again. To identify equivalent features in strict accordance with the conditions stipulated in judicial interpretation, we must make obvious subjective judgments from the perspective of ordinary technicians in this field on the basis of three basically identical objective judgments. We can properly consider the degree of creativity of the patent, and interpret the claims from a lenient or narrow perspective. It is necessary to carefully examine all kinds of non-infringement defenses and tort liability defenses in accordance with the law, reasonably identify the right of first use, and support the existing technology defenses as appropriate.