Geographic and Technological Perspectives on "Photovoltaic Cells"; preprint version

Loet Leydesdorff loet at LEYDESDORFF.NET
Tue Jan 14 02:20:21 EST 2014

Geographic and Technological Perspectives on
<> "Photovoltaic Cells:" Patents as
Instruments for Exploring Innovation Dynamics

Loet Leydesdorff, Floortje Alkemade, Gaston Heimeriks, and Rinke Hoekstra


The dynamics of innovation are nonlinear and complex: geographical,
technological, and economic selection environments can be expected to
interact. Can patents provide an analytical lens to this process in terms of
different attributes such as inventor addresses, classification codes,
backward and forward citations, etc.? Two recently developed patent maps
with interactive overlay techniques--Google Maps and maps based on citation
relations among International Patent Classifications (IPC)--are elaborated
into dynamic versions that allow for online animations and comparisons by
using split screens. Various forms of animation are explored. The recently
developed Cooperative Patent Classifications (CPC) of the U.S. Patent and
Trade Office (USPTO) and the European Patent Office (EPO) provide new
options for a precise delineation of samples in both USPTO data and the
worldwide patent database PatStat of EPO. Among the "technologies for the
mitigation of climate change" (class Y02), we zoom in on nine material
technologies for photovoltaic cells; and focus on one of them (CuInSe2) as a
lead case. The longitudinal development of Rao-Stirling diversity in the
IPC-based maps provides a heuristics for studying technological generations
during the period under study (1975-2012). The sequencing of generations
prevails in USPTO data more than in PatStat data because PatStat aggregates
patent information from countries in different stages of technological
development, whereas one can expect USPTO patents to be competitive at the
technological edge. 


Available at

** apologies for cross-postings



Loet Leydesdorff 

Professor, University of Amsterdam
Amsterdam School of Communications Research (ASCoR)

 <mailto:loet at> loet at ;
Honorary Professor,  <> SPRU, University of
Sussex; Visiting Professor,  <>
ISTIC, Beijing;

Visiting Professor,  <> Birkbeck, University of London.


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