(19)

(11)

EP 0 909 401 A1

(12)

(43) Date of publication: 21.04.1999 Bulletin 1999/16 (21) Application number: 97928351.0 (22) Date of filing: 25.06.1997

(51) International Patent Classification (IPC):  G02B 6/ 44( . ) G02B 6/ 48( . ) (86) International application number: PCT/GB1997/001698 (87) International publication number: WO 1998/000742 (08.01.1998 Gazette 1998/01)

(84) Designated Contracting States: ES FR GB IT (30) Priority: 01.07.1996 GB 19960013745 (71) Applicant: BICC Public Limited Company London W1X 5FH (GB)	(72) Inventors: ROWLAND, Simon, Mark Cheshire CW6 0TP (GB) TAHA, Arif, Jameel Chester CH2 3LT (GB) WHITESMITH, Peter, John Tarporley, Cheshire CW6 9PS (GB) (74) Representative: Poole, Michael John  BICC plc Patents and Licensing Department Quantum House Maylands Avenue Hemel Hempstead, Herts. HP2 4SJ Hemel Hempstead, Herts. HP2 4SJ (GB)