W.A. Groen (Pim)

Prof. dr. Pim Groen


Faculty of Aerospace Engineering, Room: NB 1.28

Kluyverweg 1
2629 HS Delft, The Netherlands
Tel: +31 (0)15 2781607
Fax. +31 (0)15 2784472
Email: w.a.groen@remove-this.tudelft.nl






In 1987 I graduated at Leiden University on the field of Solid State Chemistry working on crystal structures of perovskites. Hereafter I worked two years as AIO2 also in Leiden. I did my PhD in 1990 in the field of ceramic superconductors. I joined Philips Research in 1987 where I worked in Eindhoven on inorganic materials for electronic applications and later in Philips Forschung Aachen (Germany) on electronic ceramics, including piezoelectric ceramics. When Philips stopped its activities in the field of passive components I joined Morgan Electroceramics as R&D manager in 2002 where I was responsible for projects with customers to implement piezo-technology into their products. Furthermore, I led a project on a new production line for the making of multilayer piezoelectric actuators. From January 2008 until September 2011, I was department head of the group Materials Performance at TNO Science and Industry. Since 2011 I am working at the Holst Centre as programme manager for the programs “Large Area Printing” and “Printed Conductive Structures”. In 2009, I joined the Novel Aerospace Materials (NovAM) group as a visiting scientist starting new activities in the field of Smart Materials & Sensors. Since 2012 I am a part time full Professor at the faculty of Aerospace Engineering on the chair “SMART Materials” next to my work at the Holst Centre.


Current projects

Smart materials 

More information on the facilities within the smart materials portion of the NovAM group can be found here.


Light Touch Matters

February 2013 marked the start of Light.Touch.Matters, in which designers and material researchers join forces to develop a fully-new generation of smart materials that can sense touch and respond with luminescence. The base technologies are novel piezo plastics and flexible OLEDs. Being thin, flexible and formable, these light touch materials promise to revolutionize product interface design by integrating luminescence and touch in such a way that eventually the product becomes the interface. During the project, various technology demonstrators will be developed to demonstrate the potential of such novel interface technologies, principally within the domain of care, although opportunities for spin-off to other domains (e.g. automotive) will also be addressed. Light.Touch.Matters is a unique cooperation between product designers and material scientists, with 17 partners from 9 EU countries. It is funded through a grant in the European Commission’s 7th Framework Programme and will run for 3.5 years until July 2016. See more at: http://www.light-touch-matters-project.eu/ltm-what/#sthash.e9nwc65r.dpuf





Novel concepts for piezoelectric composites in sensor devices and energy harvesting

Piezoelectric sensors offer tremendous benefits for many sensing applications, by being able to convert mechanical energy to electrical energy. Applications range from pressure switches to damage detection systems. In addition piezoelectric materials are well suited as electrical energy generators (power harvesting systems). State-of-the-art piezoelectric materials such as PZT ceramics and PVDF polymers possesses several drawbacks in other areas, which limits their use as successful sensor and energy scavenger materials. Piezoelectric composites have the potential of overcoming many of these drawbacks, but generally suffer from compromised piezoelectric properties, ultimately lowering the output signal. Novel concepts are being explored to exploit the composites advantages, while employing novel techniques to increase piezoelectric signal output from these materials to a higher level. An important topic in the aviation industry is Structural Health Monitoring. Currently, the safety of airplanes is secured by inspections at regular intervals which are optical or by ultrasound. In the ideal case, sensors for SHM will be built into the airframe and connected to a network. In case of difficult to reach places wireless sensors will be incorporated in the structural system. However, the lifetime of such systems is limited by the lifetime of the batteries which are used to power these systems. Solution for this can be found by energy scavenging or harvesting systems. Part of these systems are also based on piezoelectric materials by the application is still very limited. Both energy harvesting systems and sensors for SHM will be part of the new research.  



Visiting Ian Reaney’s group in 2012.




Visiting the Holst Centre in 2014, with NovAM master's students, as part of the course on: Sensor materials (AE4ASM104).



Courses at TU Delft


AE4ASM002 - Designing materials with aerospace specific properties

AE4ASM104 - Sensor Materials



List of Publications



1.              Jan Holterman and Pim Groen;

                 An Introduction to Piezoelectric Materials and Components,

                 First published June 2012, ISBN 978-90-819361-0-1, NUR 971;

                 Published by: Stichting Applied Piezo, P.O. Box 4176, 7320 AD Apeldoorn, the Netherlands


2.              Jan Holterman and Pim Groen;

                 An Introduction to Piezoelectric Materials and Applications,

                 First published April 2013, ISBN: 978-90-819361-1-8;

                 Published by: Stichting Applied Piezo, P.O. Box 4176, 7320 AD Apeldoorn, the Netherlands


Book chapter

1.              Sybrand van der Zwaag, Daan A. van den Ende and Wilhelm Albert (Pim) Groen,

                 Sensing and Energy Harvesting Novel Polymer Composites (Chapter 16) in Materials Experience;

                 In: Fundamentals of Materials and Design,

                 Edited by Elvin Karana, Owain Pedgley Valentina Rognoli,

                 First published 2014, I Butterworth-Heinemann, Oxford, OX5 1GB, UK, IBN: 978-0-08-099359-1



Academic Publications (peer reviewed journals)

68.           Tamara M. Eggenhuisen, Michiel J.J. Coenen, Thijs W.L. Slaats, Harrie Gorter, Jörgen Sweelssen and Pim Groen,

                “Large Area Inkjet Printing for Organic Solar Cells and OLEDs using on-Halogenated Ink Formulations,"

                Journal of Imaging Science and Technology, submitted 2014.


67.           H. Khanbareh, S. van der Zwaag and W.A. Groen,

               “Effect of dielectrophoretic structuring on piezoelectric and pyroelectric properties of lead titanate-epoxy composites,”

                submitted to J. Appl. Phys.


66.           T. M. Eggenhuisen, Y. Galagan, Erica W.C. Coenen, P. Voorthuijzen, T. Slaats, S. Shanmuganam, M. Coenen, R. Andriessen and W.A. Groen,

                “Large Area Organic Photovoltaic Cells and Modules with Multiple Inkjet Printed Layers,”

                 submitted to Adv. Energy Mater. 2014.


65.           M.J.J. Coenen, M.W.L. Slaats, T.M. Eggenhuisen, H. Gorter and W.A. Groen,

               “Inkjet printing the three organic device layers of two-colored OLEDs,”

                Organic Elec. 2013.submitted.


64.           N. K James, U. Lafont, S. van der Zwaag and W.A. Groen,

               "Piezoelectric and mechanical properties of fatigue resistant, self healing PZT-ionomer composites,"

               submitted Nov. 2013 to Journal of Intelligent Material Systems and Structures .


63.           D.A. van den Ende, H.R. Fischer, W.A. Groen and S. van der Zwaag,

               “Switchable friction of piezoelectric composite-silicon wafer contacts, ”

                Appl. Phys. Lett. 102, 14, 141603, DOI: 10.1063/1.4801459 (2013).


62.           H.J. van de Wiel, Y. Galagan, T.J. van Lammeren, J.F.J. de Riet, J. Gilot, M.G.M. Nagelkerke, R.H.C.A.T. Lelieveld, S. Shanmugam,

                A. Pagudala, D. Hui, W.A. Groen,

               “R2R embedded conductive structures integrated into OPV devices, “

                Nanotechnology 24, 48, 484014.


61.           H. Gorter, M.J.J. Coenen, M.W.L. Slaats, M. Ren, W. Lu, C.J. Kuijpers, W.A. Groen,

               “Large Area Coating via Inkjet Printing for Printed OLED,”

                Thin Solid Films 532, 11-15 (2013).


60.           Nijesh Kunnamkuzhakkal James, Daan A. van den Ende, Ugo Lafont, Sybrand van der Zwaag and Wilhelm A. Groen,

               "Piezoelectric and mechanical properties of structured PZT–epoxy composites,"

                J. Mater. Res. 28 (2013) 635-641.


59.           Robert Abbel, Tim van Lammeren, Rob Hendriks, Jeroen Ploegmakers, Erwin R. Meinders, and Wilhelm A. Groen,

                "Photonic sintering of silver nanoparticle inks – a fast and convenient method for the production of highly conductive structures on foil,"

                MRS Communications (2012), 1 of 6, doi:10.1557/mrc.2012.28.


58            D.A. van den Ende, S.E. van Kempen, X. Wu, W.A. Groen, C.A. Randall, S. van der Zwaag,

               “Dielectrophoretically structured piezoelectric composites with high aspect ratio piezoelectric particles inclusions,”

                J. Appl. Physics 111, 124107 (2012).


57.           D. A. van den Ende, W.A. Groen and S. van der Zwaag,

                “Robust piezoelectric composites for energy harvesting in high strain environments,”

                Journal of Intelligent Material Systems and Structures 2012.


56.           D. A. van den Ende, H. J. van de Wiel, W .A. Groen and S. van der Zwaag,

                “Direct strain energy harvesting in automobile tires using piezoelectric PZT-polymer composites,”

                 Smart Mater. Struct. 21 015011 (2012).


55.           R. Mikkenie, O. Steigelmann, and W.A. Groen,

                "A quick method to determine the capacitance characteristics of thin layer X5R multilayer capacitors,”

                Eur. J. of Ceram 132,167-173 ( 2012).


54.           D.A. van den Ende, W.A. Groen, S. van der Zwaag,

                "The effect of calcining temperature on the properties of 0-3 piezoelectric composites of PZT and a liquid crystalline thermosetting polymer “,

                J. Electroceramics  27, 13-19 (2011).


53.           D.A. van den Ende, W.A. Groen and S. van der Zwaag,

               “Development of temperature stable charge based piezoelectric composite quasi-static pressure sensors“,

                Sensors and Actuators -Physical 163, 25-31 (2010).


52.           D.A. van den Ende, B. Bory, W.A. Groen, S. van der Zwaag,

               “Piezoelectric properties of quasi-1-3 composites by dielectrophoresis,”

                Integrated Ferroelectrics 114, 108-118 (2010).


51.           W.A. Groen, K. Prijs and S. Saeed,

               “Dependence of piezoelectric properties on layer thickness for multilayer actuators”, 

                Integrated Ferroelectrics 115, 132-141 (2010).


50.           R. Mikkenie, W.A. Groen and R. van der Drift,

               “Diffusion of silver during sintering in high permittivity COG dielectrics,” 

                Integrated Ferroelectrics 114, 72-80 (2010).


49.           D.A. van den Ende, B.F. Bory, W.A. Groen, S. van der Zwaag,

               “Improving the d33 and g33 properties of 0-3 piezoelectric composites by dielectrophoresis,”

                J. Appl. Physics 107, 024107 (2010).


48.           D. Irimia, D. Dobrikov, R. Kortekaas, H. Voet, D. A. van den Ende, W. A. Groen and M. H.M. Janssen,

               “A short pulse (7 ¹s FWHM) and high repetition rate (DC-5 kHz) cantilever piezo valve for pulsed atomic and molecular beams,”

                Review of Scientific Instruments 80, 113303 (2009).


47.           D.A. van den Ende, B. Bos, W.A. Groen and L.M.J.G. Dortmans,

               ”Lifetime of piezoelectric multilayer actuators: Interplay of material properties and actuator design,”

                J. Electroceramic 22, 163 (2009).


46.           D.A. van den Ende, B. Bos and W.A. Groen,

               “Non-linear electromechanical behaviour of piezoelectric bimorph actuators: influence on performance and lifetime,”

                J. Electroceramics 22, 185 (2009).


45.           M.D. Snel, W.A. Groen and G. de With,

               “New piezoelectric ceramics in system Bi(Mg0.75W0.25O3 – PbTiO3,”

                J. Europ. Ceram. Soc. 26, 89 (2006).


44.           M.D. Snel, W.A. Groen and G. de With,

                “Investigation of the piezoelectric system (1-x)Bi(Mg1/2Ti1/2)O3 – x PbTiO3,”

                J. Europ. Ceram. Soc. 25, 3229 (2005).


43.           W.A. Groen,  C. Metzmacher, V. Zaspalis,  P. Huppertz  and S. Schuurman ,

                “Aging of NTC Ceramics in the system Mn-Ni-Fe-O,”

                Eur. J. Ceram Soc. 21, 1793 (2001).


42.           H.A.M. van Hal, W.A. Groen, S. Maassen W.C. Keur,

                “Mechanochemical synthesis of BaTiO3, Bi0.5Na0.5TiO3 and Ba2NaNb5O15 dielectric ceramics,”

                J. Europ.Ceram. Soc. 21, 1689 (2001).


41.           W.A. Groen, C. Metzmacher, P. Huppertz  and S. Schuurman,

                “Aging of NTC Ceramics in the system Mn-Ni-Fe-O,”

                Journal of Electroceramics 7, 77 (2001).


40.           C. Metzmacher, W.A. Groen and I.M. Reaney,

                “Microstructure and Electrical properties of Mn-Ni-In Spinels,”

                Phys. Status Solidi (a) 181:2, 369 (2000).


39.           C. Metzmacher, R. Mikkenie and W.A. Groen,

                “Indium containing ceramics with negative temperature coefficient characteristic,”

                Eur. J. Ceram. Soc 20, 997 (2000).


38.           W.A. Groen, V. Zaspalis and S. Schuurman,

                “Aging of NTC ceramics investigated by magnetic measurements,”

                J.Mater. Sci. Lett. 18, 1233 (1999).


37.           Wen-Hsi Lee, W.A. Groen, Herbert Schreinemacher and Detlev Hennings,

                “Dysprosium doped dielectric material for sintering in reducing atmosphere,”

                J. of Electroceramics 5, 31 (2000).


36.           M.J. van Bommel, W.A. Groen, H.A.M. van Hal, W.C. Keur and T.N.M. Bernards,

                “The electrical and optical properties of thin layers of nano-sized antimony doped tinoxide particles,”

                J. Mater Sci 34, 4803 (1999).


35.           W.A. Groen, M.J. Kraan, P.F. van Hal, N. Sweegers and G. de With,

                "Preparation and properties of ALCON ceramics,"

                J. Mater. Sci. 30, 475 (1995).              


34.           W.A. Groen, M.J. Kraan, P.F. van Hal and A.E.M. De Veirman,

               "A new diamond related compound in the system Al2O3 Al4C3 AlN,"

               J. Sol. State Chem., 120, 211.


33.           H.T. Hintzen, R.Bruls, A. Kudyba, W.A. Groen and R. Metselaar,

                "Powder preparation and densification of MgSiN2 ,”

                Ceramic Transactions, 51, 585 (1995).


32.           M.A. van Veenendaal, G.A. Sawatzky and W.A. Groen,

               "Electronic structure of Bi2Sr2Ca1 xYxCu2O8+δ: Cu 2p x ray photoelectron spectra and occupied and unoccupied low energy states,"

                Phys. Rev. B49, 1407 (1994).


31.           H.T. Hintzen, W.A. Groen, M.J. Kraan, R. Metselaar,

               "Hot pressing of MgSiN2 ceramics,"

                J. Mater. Sci. Lett. 13, 1314 (1993) .


30.           W.A. Groen, M.J. Kraan and G. de With,

               "New ternary nitride ceramics: CaSiN2," 

                J. Mater. Sci., 29, 3161 (1994).


29.           W.A. Groen, M.J. Kraan and G. de With,

                "Preparation, microstructure and properties of MgSiN2 ceramics,"

                J. Eur. Cer. Soc. 12, 413 (1993).


28.           W.A. Groen and P.F. van Hal,

               "High temperature electrical conductivity of AlN ceramics,"

                Britisch Ceramic Transactions 93, 192 (1994).


27.           T.A.M. Haemers, D.J.W. IJdo, W.A. Groen, H.A.M. van Hal and R.B. Helmholdt,

                "Structure detemination of Praseodymium Hexaaluminate,"

                Mat. Res. Bull. 28, 111 (1993).


26.           W.A. Groen, J.L. van Lierop and A. Roosen,

                "Electrical and thermal conductivity of AlN ceramics doped with beryllium and oxygen,"

                J. Mater. Sci. Lett. 12, 1224 (1993).


25.           W.A. Groen, J.G. van Lierop and J.M. Toonen,

                "Electrical conductivity of AlN ceramics at High Temperatures,"

                J. Eur. Ceram. Soc. 11, 353 (1993).


24.           A.J. Smits, W.J. Elion, W.A. Groen, L.J. de Jongh and J.M. van Ruitenbeek,

               "Transport properties of Bi2Sr2 xLaxCuO6+δ,"

               Physica C199, 276 (1992).


23.           M.A. van Veenendaal, R. Schlatmann, W.A. Groen and G.A. Sawatzky,

                "Doping dependance of the chemical potential in Bi2Sr2Ca1 xYxCu2O8+δ,"

                Phys. Rev. B47 , 446 (1993).


22.           A.J. Smits, W.J. Elion, W.A. Groen, L.J. de Jongh and J.M. van Ruitenbeek,

                "Transport properties of Bi2Sr2 xLaxCuO6+δ,"

                Japanese Journal of Applied Physics, Part 1, 31, 276 (1992).


21.           H.W. Zandbergen, W.A. Groen, A. Smit and G. van Tendeloo,

                "Structure and properties of (Bi,Pb)2Sr2(Ca,Y)Cu2O8+δ,"

                Physica C168, 426 449 (1990).


20.           H.B. Brom, D. Reefman, J.C. Jol, D.M. de Leeuw and W.A.Groen,

                "205Tl NMR in Tl2Ba2CuO6 and the t J model,"

                Phys. Rev. B41, 7261 (1990).


19.           D.M. de Leeuw, W.A. Groen, L.F. Feiner and E.E. Havinga,

               "Correlation between the superconducting transition temperature and the crystal structure of high Tc cuprate compounds,"

                Physica C166, 133 (1990).


18.           W.A. Groen, D.M. de Leeuw and G.P.J. Geelen,

                "Hole concentration and Tc in Bi2Sr2CuO6+δ,"

                Physica C165, 305 (1990).


17.           D.M. de Leeuw, W.A. Groen, J.C. Jol, H.B. Brom and H.W. Zandbergen,

                "Hole doping in Tl2Ba2CuO6+δ  (Tc=0 80K) investigated by 205Tl nuclear magnetic resonance,"

                Physica C166, 349 (1990).


16.           H.W. Zandbergen and W.A. Groen,

                "New superstructures in as synthezised and in situ heated (Bi,Pb)2Sr2YCu2O8+δ,"

                Physica C166, 282 (1990).


15.           W.A Groen, D.M. de Leeuw and L.F. Feiner,

                "Hole concentration and Tc in Bi2Sr2CaCu2O8+δ,"

                Physica C165, 55 (1990).


14.           W.A. Groen, D.M. de Leeuw and G.M. Stollman,

                "Oxygen content, lattice constants and Tc of Bi2Sr2 xLaxCuO6+δ with 0.0 < x < 1.0,"

                Sol. State Comm. 72, 697 (1989).


13.           W.A. Groen and D.M. de Leeuw,

               "Oxygen content, lattice constants and Tc of Bi2Sr2CaCu2O8+δ,"

                Physica C159, 417 (1989).


12.           H.W. Zandbergen, W.A. Groen, G. van Tendeloo and S. Amelinckx,

                "High resolution electron microscopy and electron diffraction on Bi2Sr2 xLaxCanCu1+nO6+2n+δ,"

                Appl. Phys. A48, 305 (1989).


11.           W.A. Groen, R. Steens, H.W. Zandbergen, M.W. Dirken, F.M. Mulder and R.C. Thiel,

                "Substitution of calcium by rare earth elements in the high Tc superconductor Bi2Sr2CaCu2O8+δ,"

                J. of the Less Common Metals 155, 133 (1989).


10.           S. Olivier, W.A. Groen, C. van der Beek and H.W. Zandbergen,

                "On the solid solutions in the systems Bi2Sr2Ca1 xYxCu2O8+δ, Bi2Sr2 xLaxCaCu2O8+δ and Bi2Sr2Y1 xCexCu2O8+δ,"

                Physica C157, 531 (1989).


9.              H.W. Zandbergen, W.A. Groen, F.C. Mijlhoff, G. van Tendeloo and S. Amelinckx,

                 "Models for the modulation in A2B2CanCu1+nO6+2n, A, B=Bi,Sr or Tl, Ba and n=0,1,2,"

                 Physica C156, 325 (1988).


8.              W.A. Groen and H. W. Zandbergen,

                 "A study of Bi2Sr2 xLaxCuO6+δ with X ray and electron diffraction,"

                 Sol. State Comm. 68, 527 (1988).


7.              R.A. Zacher, H.W. Zandbergen, J. van den Berg, W.A. Groen, A.A. Menovsky, P.H. Kes and J.A. Mydosh,

                 "Properties and structure of the new high temperature superconductor: Ca Sr Bi Cu O,"

                 Bull. of the Am. Phys. Soc. 33, 1370 (1988).


6.              W.A. Groen and D.J.W. IJdo,

                 "Distrontium Diantimonate (V). A Rietveld Refinement of Neutron Powder Diffraction Data,"

                 Acta. Cryst. C44, 782 (1988).


5.              H.W.Zandbergen, P.Groen, G.vanTendeloo,J. van Landuyt and S.Amelinckx,

                 "Electron diffraction and electron microscopy of the high Tc superconductive phase in the Bi Ca Sr Cu O system,"

                 Sol. State. Comm. 66, 397(1988).


4.              W.A. Groen, F.P.F. van Berkel and D.J.W. IJdo,

                 "Trineodynium Ruthenate (V). A Rietveld Refinement of Neutron Powder Diffraction Data,"

                 Acta. Cryst. C43, 2262 (1987).


3.              P.A. Seinen, F.P.F. van Berkel, W.A. Groen and D.J.W. IJdo,

                 "The ordered perovskite system Ln2NiRuO6,"

                 Mat. Res. Bull. 22, 535 (1987).


2.              W.A. Groen and D.J.W. IJdo,

                 "The Monoclinic Perovskites Sr2CaUO6 and Ba2SrUO6. A Rietveld Refinement of Neutron Powder Diffraction Data,"

                 Acta. Cryst. C43, 1033 (1987).


1.              W.A. Groen, F.P.F. van Berkel and D.J.W. IJdo,

                 "Dineodynium Magnesium Titanate(IV). A Rietveld Refinement of Neutron Powder Diffraction Data,"

                 Acta. Cryst. C42, 1472 (1986).




1)              W.A. Groen, M.J. Kraan en G. de With,

                 “Magnesium silicium nitride ceramics”.

                  DE69407832, EP611739, JP6263543, US5411924


2)              W.A. Groen, M.J. Kraan P.F. van Hal en G. de With,

                 “Al-O-C-N substrate for Si-technology”.

                  DE69503472T2 , EP743929, JP9509394, US5635429, US5571757


3)              W.A. Groen,

                 “Indiumhaltiger oxidkeramischer Thermistor”.

                  DE19622112, EP810612, JP10092609 , US5976421


4)              W.A. Groen,

                 “Selten-erd-metallhaltiger hoch temperatur-thermistor“.

                 DE19621934 , EP0810611B1 , JP10092609, US05955937


5)              W.A. Groen and V.R.C.M.J. Sillen,

                 ”Schaltungsanordnung mit einem SMD-bauelement, insbesondere Temperatursensor und Verfahren zur Herstellung eines Temperatur


                 DE19736855, EP899550, JP11148873, US6515572


6)              S. Kordic, K. Mutsaers, M. Klee and W.A. Groen,

                 “Semiconductor device and method for manufacturing such a device”.

                 EP0968529, US6201291


7)              C.R. Ronda, C.J.M. Denissen, V. Weiler and W.A. Groen,

                 “Low pressure mercury vapor discharge lamp with electrode shield”.

                  DE69915966, EP995222, JP20025156352, US6274981


8)              A. Nellissen, P. van Oppen, H. Loebl, M. Klee, W.A. Groen and N. van Veen,

                 “Thin film capacitor”.

                  EP98204217.8, US6337790


9)              G. Greuel, W.A. Groen and S. Schuurman,

                 “Widerstandelement mit Widerstandschichten“.



10)           K. Albertsen and W.A. Groen,

                “Passives Bauelement mit Verbundstoff“.             

                 DE19939483, EP1259968, JP2003516619, US6721164


11)          A. Kraus, B. Rausenberger, W.A. Groen and H. Dannert,

               “Niederdruck-Gasentladungslampe mit hoher Leuchtdichte“.

                DE10014407, EP1137050, JP2001291492, US6858985, US2001024090


12)           W.A. Groen, P. Huppertz, K. Albertsen and B. Rausenberger,

                “Dielektrische keramische Zusammensetzung“.

                 DE10155593, EP1256971, JP2002352773, US6744204


13)           W.A. Groen, B. Rausenberger and K Albertsen,

                “Liquid crystal picture screen with improved backlighting”.

                 DE10126958, EP1263021, JP2003036816, US6713946


14)           Norbert Braun, W.A. Groen, A. Kraus, B. Rausenberger, B. Roulevink, J.A. Vorachen,

               “Gas discharge lamp and method of its manufacture”.

                DE10128139, EP1265264, JP2003068193 , US20030034735


15)           W.A. Groen and J. Pankert,

                “Gas discharge lamp”.



16)           D. Hennings, W.A. Groen, P Schmidt, R. Mauczok, P. Huppertz and B. Schreinemacher, 

                “Dielektrische keramische Zusammensetzung“.

                DE10155593, EP1036777, US5011804.


17)           H. Bechtelt, Y. Martynov, W. Busselt, W.A. Groen, P. Huppertz,

                “Display comprising a varistor layer”.

                DE10251583, EP1563715, US20060033856, JP2006505904, AU2003274450.                  


18)           D.A. van de Ende and W.A. Groen,

                “Method for manufacturing a mainly film shaped piezoelectric element”.

                WO2010229261; EP2264802-A1; WO2010147470-A1; EP2443678-A1


19)           D.A. van de Ende and W.A. Groen,

                "Piezoelectric Structure (short fiber based piezoelectric energyscavenger)."

                EP2466661-A1; WO2012087118-A1. 



Naam auteur: D.B. Deutz
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