[Purpose/significance] The meanings of potential technology opportunities become more explicit by identifying novel patents rather than patent vacancies that are usually represented as a simple set of keywords. [Method/process] We proposed an approach to detect novel patents based on systematic processes and quantitative outcomes. Density-Based Local Outlier (DLOF) algorithm was used to identify novel patents. Then, we used the scope of technology index and the number of similar patents index to structure an anomaly-portfolio patent map. [Result/conclusion] Research results show that novelty-focused patent mapping for the technology opportunity analysis can accurately identify the novel patents and provide a reference for the technology research and development.