Abstract: Investigating the temporal attributes of patent knowledge absorption and their impact on patent innovation outcomes can enhance the understanding of time effects in knowledge absorption. By employing patent citation delays, it quantifies the recency and time-span of knowledge absorbed in patents. The analysis covers 2,563,948 citing patents, 6,693,213 cited patents, and 3,978,556 cited papers from 1979 to 2013. It examines the distributions of recency and time-span in the scientific and technological knowledge incorporated into patents and explores how these temporal characteristics relate to the uncertainty of patent impact, as indicated by forward citations. Findings reveal that patents in the field of electrical engineering predominantly rely on recently acquired scientific and technological knowledge, whereas chemistry-related fields depend more on scientific knowledge absorbed over extended periods. Universities and government agencies, as opposed to firms, tend to utilize knowledge with greater recency and time-span. Results from generalized negative binomial regression indicate that higher recency in scientific and technological knowledge and greater time-span in technological knowledge significantly increase the uncertainty in patent influence, while a longer time-span in scientific knowledge decreases it.

Key words: Patent innovation, Knowledge flow, Science-technology, Recency, Time-span, Patent influence