Direct and Spillover Effects of ATP-Funded Photonics Technologies

FIGURE 14.Geographic Distribution of Citations to Displaytech Patents21 Canada31(4)130(3)211 12110(7)6(3)2129(13)Japan15(8)Europe2 TaiwanU.S. Total: 90(30)Note: values indicate number of citations (number of citing organizations).with Displaytech through the University of Colorado. The social network centered on a starresearcher, Clark, who was the mechanism for technology flows, and our analysis shows theflows to those outside Displaytech have yet to create much economic spillover value. Ourconclusion is that patent citations are, at best, a very noisy indicator of technology spillover.One of the questions motivating our study relates to the social and geographic characteristicsof technology diffusion mechanisms. Technology flows through geographically clusteredsocial ties are clearly very strong in the Displaytech case. Figure 14 shows a schematic of thisgeographic clustering among the citing patents by location (region or country) of the assignee.Silicon Valley, California, had the highest number, 31 citations by four groups, followed by theBoulder area and Japan. The U.S. total was 90 citations by 30 groups. The concentration inDisplaytech’s home state of Colorado is consistent with findings by Hicks (2002) that patentsby U.S. companies tend to be more likely to cite in-state public sector science.Yet, as an indicator of geographic clustering or social networks, this picture of patents wouldsend misleading signals. Without detailed case investigation, Gemfire in Silicon Valley, with24 citations, would look like a significant receiver of technological information, as wouldChorum in Texas and InViso in Silicon Valley. Yet Gemfire was not a receiver, and Chorum’slinks actually emerged when it was started in Boulder by researchers associated withDisplaytech 41