This paper sets out to explore the patterns of technological change and knowledge spillover in the field of flat panel display (FPD) technology, along with the catching-up behavior of latecomers, through the analysis of US patents and patent citations between 1976 and 2005. Our results show that: (i) the catching-up by FPD technology latecomers began at the transition stage (1987-1996) when the dominant design became established in areas with high ‘revealed technology advantage’ (RTA); (ii) there is no apparent localization of knowledge spillover amongst FPD technology latecomers; instead, higher citation frequencies of forerunners’ patents were found in latecomers’ FPD patents during the transition (1987–1996) and post-dominant design (1997–2005) stages and; and (iii) a few extraordinary peaks were found in the citation frequency of forerunners’ patents at long citation lags in latecomers’ FPD patents, particularly during the transition stage (1987–1996), indicative of the knowledge threshold which latecomers need to cross in order to catch up with forerunners.