(19)

(11)

EP 0 471 015 A1

(12)

(43) Date of publication: 19.02.1992 Bulletin 1992/08 (21) Application number: 90907870.0 (22) Date of filing: 26.04.1990

(51) International Patent Classification (IPC):  G01J 9/ 00( . ) G01J 1/ 42( . ) (86) International application number: PCT/US1990/002198 (87) International publication number: WO 1990/012999 (01.11.1990 Gazette 1990/25)

(84) Designated Contracting States: CH DE FR GB IT LI (30) Priority: 27.04.1989 US 19890344890 (71) Applicant: Coherent, Inc. Palo Alto California 94304 (US)	(72) Inventors: JOHNSTON, Thomas, F., Jr. Auburn, CA 95603 (US) SASNETT, Michael, W. Los Altos, CA 94022 (US) DEWEY, David, A. Sunnyvale, CA 94086 (US) WILLIAMS, Gerald, H. Meadow Vista, CA 95722 (US) (74) Representative: Jackson, David Spence, et al  REDDIE & GROSE 16, Theobalds Road London, WC1X 8PL London, WC1X 8PL (GB)