Crossref Funder ID: http://dx.doi.org/10.13039/501100001691研究費・賞番号:
Eisenman (2013) argues that the importance of design innovation increases in the early and late stages of an industry and is lowest in the middle stage. In response, this study empirically examines her proposition through an examination of mobile phones during the feature phone era (1999–2008) when various types of designs were being generated using design patent data. We analyze the number of mobile phone design patents registered before the current advent of smart phones as well as examining the yearly averages of forward citations (the number of times a particular design patent is cited in later design patents) and backward citations (the number of times a particular design patent cites previous design patents). Further, to shed light on interactions with an accumulation of design-related technology, the study also analyzes the number of design-related patent applications per year. Results reveal that while there was an increase in the number of design patents registered in the late stage of the industry, especially between the years of 2007–2008, the average number of forward citations drops below the average number of backward citations from 2003 onward. In other words, although at the late stages of the industry many design innovations emerged, most of these were incremental changes that followed past designs. In contrast, design-related patent applications reached a peak in 2004 and fell thereafter. It is hypothesized that this trend was influenced by the growing number of design-related patents that facilitated the easy generation of new variations in design. These results show the dilemma: Although design innovations continue to be generated over time by accumulating design-related technology, creating genuinely impactful design innovation becomes more difficult as time progresses. The study therefore demonstrates the difficulty of realizing Eisenman (2013)’s theoretical proposition.