(19)

(11)

EP 0 363 427 A1

(12)

(43) Date of publication: 18.04.1990 Bulletin 1990/16 (21) Application number: 88906286.0 (22) Date of filing: 26.05.1988

(51) International Patent Classification (IPC):  G01N 27/ 49( . ) (86) International application number: PCT/US1988/001772 (87) International publication number: WO 1988/009500 (01.12.1988 Gazette 1988/26)

(84) Designated Contracting States: DE FR GB (30) Priority: 26.05.1987 US 19870053705 (71) Applicant: TRANSDUCER RESEARCH, INC. Naperville, IL 60540 (US)	(72) Inventors: STETTER, Joseph, R. Naperville, IL 60540 (US) MACLAY, G., Jordan Maywood, IL 60153 (US) (74) Representative: Fort, Jacques  CABINET PLASSERAUD 84, rue d'Amsterdam F-75009 Paris F-75009 Paris (FR)