(19)

(11)

EP 0 857 317 A1

(12)

(43) Date of publication: 12.08.1998 Bulletin 1998/33 (21) Application number: 96932703.0 (22) Date of filing: 04.10.1996

(51) International Patent Classification (IPC):  G02B 27/ 22( . ) G02B 27/ 60( . ) (86) International application number: PCT/GB1996/002417 (87) International publication number: WO 1997/014988 (24.04.1997 Gazette 1997/18)

(84) Designated Contracting States: DE FR GB NL (30) Priority: 17.10.1995 GB 19950021263 08.01.1996 GB 19960000292 (71) Applicant: CENTRAL RESEARCH LABORATORIES LIMITED Hayes, Middlesex, UB3 1HH (GB)	(72) Inventor: MARMAROPOLOUS, George Hayes Middlesex UB3 1HH (GB) (74) Representative: Leaman, Keith, et al  QED Patents Limited, Dawley Road Hayes, Middlesex UB3 1HH Hayes, Middlesex UB3 1HH (GB)