Abstract: In this paper, a circumvention design method which taking patent group as target, function requirement as the basis for circumvention and the extension theory as the theoretical tool was proposed. Firstly, online product reviews were used as requirement acquisition resources, which were transformed into several functional requirements by using natural language processing technology and extension primitive model. Secondly, the target patent group was researched by the keywords from the online reviews and IPC classification code, then the patent group function model was built by analyzing each patent text. Thirdly, the obtained function requirements were matched with the patent group function model to confirm the contents in patent group function model to be circumvented. Fourthly, the function requirements were guided by the extension analysis as the path for circumvention analysis, and the extension transformation was used to express the circumvention solution operation, then the new scheme was determined whether exists the technical features of infringement. Finally, a medicine storage box patent group was taken as case study to confirm the feasibility of the above process of patent group circumvention design. Taking functional requirements as the basis for circumvention can help reduce the influence of subjective judgment in confirming the content to be circumvented in the process of patent group circumvention, and at the same time ensure that the subsequent circumvention solution is carried out in the direction of satisfying users’ function requirements.

Key words: function requirement, patent circumvention, primitive model, extension analysis, extension transformation