(19)

(11)

EP 0 636 253 A1

(12)

(43) Date of publication: 01.02.1995 Bulletin 1995/05 (21) Application number: 94906337.0 (22) Date of filing: 16.02.1994

(51) International Patent Classification (IPC):  G02B 6/ 42( . ) (86) International application number: PCT/GB1994/000313 (87) International publication number: WO 1994/019718 (01.09.1994 Gazette 1994/20)

(84) Designated Contracting States: DE GB (30) Priority: 17.02.1993 GB 19930003169 (71) Applicant: BT&D TECHNOLOGIES LTD. Bracknell, Berkshire RG12 1HN (GB)	(72) Inventor: MEADOWCROFT, Simon, George, Preston Suffolk IP14 1TU (GB) (74) Representative: Webster, Denise Mary  Hewlett-Packard Ltd, IP Section, Building 2, Filton Road, Stoke Gifford Bristol BS12 6QZ Bristol BS12 6QZ (GB)