(19)

(11)

EP 0 258 300 A1

(12)

(43) Date of publication: 09.03.1988 Bulletin 1988/10 (21) Application number: 87901074.0 (22) Date of filing: 29.01.1987

(51) International Patent Classification (IPC):  G02B 23/ 08( . ) G09B 9/ 06( . ) (86) International application number: PCT/GB1987/000063 (87) International publication number: WO 1987/004803 (13.08.1987 Gazette 1987/18)

(84) Designated Contracting States: BE DE FR GB IT NL SE (30) Priority: 31.01.1986 GB 19860002428 (71) Applicant: PIR REAL Port Dundas Glasgow G4 0LF (GB)	(72) Inventor: MISSON, Pierre Glasgow G63 9PD (GB) (74) Representative: Pattullo, Norman  Murgitroyd and Company 373 Scotland Street Glasgow G5 8QA Glasgow G5 8QA (GB)