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Abstract
We analyze the spatial diffusion of laser technology research in West Germany from 1960, when this technology began, until 2005. Early adoption of laser technology research was especially prevalent in large agglomerations. While we cannot detect knowledge spillovers from adjacent regions, geographic proximity to the center of initial laser research was conducive to early adoption of laser research; however, the effect is negligibly small. The earlier a region embarked on this type of research, the higher the level of laser research later, indicating the accumulation of knowledge generated in previous periods. Our results highlight the role of a region's absorptive capacity for commencing and conducting research in a new technological field. An interregional transfer of tacit knowledge was largely unimportant for the spatial diffusion of research in this technological field.
Notes
1. This paper is based on the project ‘Emergence and Evolution of a Spatial-Sectoral System of Innovation: Laser Technology in Germany, 1960 to Present’ sponsored by the German Volkswagen Stiftung and jointly conducted by the Friedrich Schiller University Jena, the Max Planck Institute for Economics, Jena, the Technical University Bergakademie Freiberg, and the University of Kassel. We are particularly indebted to our co-workers in this project, Helmuth Albrecht, Guido Bünstorf, Cornelia Fabian, and Matthias Geissler, for their cooperation. Moreover, Wolfgang Ziegler and Sebastian Schmidt of the patent office of the Friedrich Schiller University Jena provided invaluable help in preparing and processing the data. Our analysis of laser patents considerably benefited from the work of Martin Gehlert and Jana Hofmann, as documented in their diploma theses. All errors are, of course, the responsibility of the authors. We gratefully acknowledge helpful comments by Bo Carlsson, Koen Frenken, Steven Klepper, and Raquel Ortega Argilés on earlier versions of this paper, as well as advice on econometric issues from Florian Noseleit. We have particularly benefited from conversations with Dieter Röß who was the first to realize a laser in Germany while working for the Siemens Company. Three anonymous referees provided valuable advice for improving the paper.
2. The most relevant fields of engineering for laser technology research are electrical engineering, high-frequency engineering, as well as information and communication technology.
3. Producers of laser beam sources did indeed conduct a large share of the research and applied for about 53% of German patents in the IPC class H01S. Taking also into account private firms that did not supply laser beam sources, this share amounts to about 78%.
4. One industry that has been of considerable importance for laser applications in the German context was mechanical engineering. Empirically, the distinction between suppliers of laser sources and users in the early stages of the German laser industry is somewhat fuzzy. CitationBuenstorf, Fritsch, and Medrano (2012) provide evidence that most of the producers of laser sources diversified downstream at some time by supplying whole laser systems for certain applications such as mechanical engineering, measurement, etc. Also some of the producers of laser systems that first purchased the laser sources on the market started to develop and manufacture beam sources themselves. A main motivation for such a diversification upstream was that these firms wanted laser sources that were better suited for their specific needs than those available on the market.
5. For considering the patent applications that may have taken the Patent Cooperation Treaty route, we have further consulted the STN database (www.stn-international.de).
6. These sources are the Bibliographische Mitteilungen der Universitätsbibliothek Jena, 1960–1971 (CitationUniversitätsbibliothek Jena 1972).
7. However, for historical reasons, the cities of Bremen/Bremerhaven, and Hamburg are planning regions without surrounding districts.
8. Having functional regions is particularly advantageous for the regional assignment of inventors. As stated above, we locate inventors by their place of residence that is in most cases not where the respective research is performed. At the rather small-scale level of districts to assign inventors to the region where they reside would lead to mistakes if the respective laboratory would be in a different district. At the level of planning regions this problem is negligible. In our analysis, we do not account for any address changes that could be detected in the patent statistics in the case that an inventor has filed another patent at a later point of time for two reasons. First, such a ‘correction’ of the regional knowledge base could only be done for those inventors that have filed other patents. Second, the level of interregional mobility that can be detected from the patent statistics is rather low and the results are in no way sensitive to this kind of mobility.
9. See German CitationFederal Office for Building and Regional Planning (2003) for the definition of planning regions and districts.
10. In 1954, Charles H. Townes, James P. Gordon, and Herbert J. Zeiger presented the ammonia-gas beam oscillator, an important technological breakthrough. Townes coined the term ‘maser’ for this type of amplifier, an acronym for microwave amplification by stimulated emission of radiation (CitationBertolotti 2005; CitationRöss 1969).
11. The information on the early adoption of laser technology research by Siemens is largely based on CitationAlbrecht (1997) and on personal conversation with Dieter Röß, who was the first to realize a laser in Germany.
12. In terms of inhabitants, the Munich region was somewhat smaller than West Berlin but can be regarded as having had better preconditions for laser technology adoption because private firms avoided locating important research facilities in West Berlin due to the city's precarious political-geographic situation. Chiefly for this reason, Siemens relocated its main administrative and research facilities to Munich and to Erlangen after World War II.
13. Analytical knowledge is largely based on formal models and codified science so that its communication requires much less transfer of related tacid knowledge as is the case for ‘synthetic’ knowledge that is more based on experience. See CitationAsheim and Gertler (2005) for a more detailed description of the two types of knowledge base.
14. The number of patent applications is restricted to former West Germany. The Berlin region is excluded because information on this region is not comparable over time due to the change of definition of this region after German Unification in 1990.
15. In the first three years (1961–1964), Siemens’ share of all German patent applications in the field of laser technology amounted to about 72%.
16. This includes 13 ‘star scientists’ who are named on 10 or more patent applications. Dieter Röß is named as an inventor in 95 patent applications, Günter Zeidler in 27, Eberhard Groschwitz in 26, and Karl Gürs in 25; all of them were at that time working for Siemens in its Munich laboratory.
17. Identifying inventors in the patent applications who are affiliated with academic institutions is problematic because, until the year 2002, German professors had the privilege of filing inventions as their own. Hence, patent applications by universities are rather rare in the 1960–2002 period and many university scientists may be classified as independent inventors. In the case where the invention emerged due to cooperation between a university and a private-sector firm, the university inventors may be assigned to an industry. By matching names of inventors from patent statistics with authors of publications for whom we know their affiliations, we are able to identify patents of inventors working in academic institutions. On the basis of this information, we can assign 2.6% of the inventors in the 1961–1970 period to universities. The share of inventors from public research organizations in which university professors were not permitted to patents in their own names is also small (3.25%) during that period.
18. For the development of the German market for laser beam sources, see CitationBuenstorf (2007).
19. In 1978, Siemens finalized its acquisition of the Osram company, which in the 1990s begun to conduct research on laser beam sources in Regensburg and also became a producer.
20. That we approximate the regional diffusion of research by the event of patent applications leads to certain limitations that are well recognized in the literature (see, CitationGriliches 1990). Six regions did not have any patent application until 2005 but may have patented afterwards.
21. The reason we could not estimate the Cox proportional hazard model with time dummies is probably that this type of model already accounts for the time dimension by the unspecified baseline hazard rate, so that the inclusion of time dummies creates redundant variables that add unnecessary complexity to the model with regard to the number of observations.
22. We also tested the impact of three other measures of distance. Instead of distance to Munich, we included distance to Stuttgart, a region that also played a leading role with respect to the number of laser patents. This led to results similar to those achieved with distance to Munich variable. Including the distance to Aachen, a region with a leading technical university but no early adoption of laser technology, showed no statistically significant effect, whereas the distance to Hamburg, a region located far from Munich and a late adoption of laser research, showed a significantly positive effect, indicating that the longer the distance to Hamburg, the lower the likelihood of adopting laser research. Several extensions of the models, including interaction terms, were tested, but the main results did not change.
23. Running models with one of the two variables only, we find a considerably stronger effect for the number of population.
24. For instance, if a region had its first patent application in 1971, it is assigned the value of 35. If a region has its first patent in 2005, the value is 1. In the case of no patent applications at all, the value is 0.
25. If a patent has several inventors located in different regions, the patent is divided by the number of inventors and assigned to the region of inventor residence with the respective share of that patent. In the event, this procedure leads to numbers of regional patent applications that are not whole numbers, the numbers are rounded up.
26. For a more detailed description of these estimation methods, see also Greene (Citation2008, 909–912).
27. For fixed effects estimations, see in Appendix 1.
28. The share of zero cases is 73% of all observations.
29. Note that West Germany consists of 10 Federal States. Estimations including dummies for each planning region were not feasible given the increased number of independent variables in the model.
30. Unfortunately, data about industry structure of the regional firm population are not available for the period under inspection so that the effect of related variety cannot be tested systematically here.
31. There are several firms in more remote locations that engaged in laser technology research at a rather early date. One such example is Haas, a mid-sized and in the 1960s well-established producer of clocks and other fine mechanical products located in a small town in the Black Forest. Haas, together with the Batelle Institute in Frankfurt (Main) located more than 200 km away, developed applications of laser technology (welding) for its own production purposes as early as the late 1960s. It then started to produce this type of equipment for other firms and became a producer of laser beam sources in 1975. Haas filed its first patent application in the IPC H01S in the year 1973.
32. Public policy did not play any significant role in the early development stages of laser technology in Germany. For a detailed assessment of innovation policy in the field of laser technology in Germany, see CitationAlbrecht (1997) and CitationFabian (2012).
33. Specifically, when obsolescence is the same across different fields and diffusion is allowed to vary, the estimated value of β1 is 0.104. When the diffusion is taken as similar for different technological fields and depreciation is allowed to vary, their estimate of β2 is of 0.436 (CitationHall, Jaffe, and Trajtenberg 2002, 445).
34. Such conditions are also present in a former study from CitationJaffe and Trajtenberg (1999) that uses a much larger of covariates including also the geographical information of both the potentially cited patent and the potentially citing patent.