(19)

(11)

EP 0 616 693 A1

(12)

(43) Date of publication: 28.09.1994 Bulletin 1994/39 (21) Application number: 92924744.0 (22) Date of filing: 09.12.1992

(51) International Patent Classification (IPC):  G01R 27/ 26( . ) (86) International application number: PCT/FI1992/000334 (87) International publication number: WO 1993/012437 (24.06.1993 Gazette 1993/15)

(84) Designated Contracting States: DE FR GB IT (30) Priority: 10.12.1991 FI 19910005799 (71) Applicant: VALTION TEKNILLINEN TUTKIMUSKESKUS SF-33101 Tampere (FI)	(72) Inventor: HUOVILA, Henrik SF-33210 Tampere (FI) (74) Representative: Joly, Jean-Jacques, et al  Cabinet Beau de Loménie 158, rue de l'Université F-75340 Paris Cédex 07 F-75340 Paris Cédex 07 (FR)