(19)

(11)

EP 0 292 533 A1

(12)

(43) Date of publication: 30.11.1988 Bulletin 1988/48 (21) Application number: 88900032.0 (22) Date of filing: 09.12.1987

(51) International Patent Classification (IPC):  G02B 5/ 08( . ) C30B 23/ 02( . ) G02B 5/ 30( . ) H01L 21/ 203( . ) C23C 14/ 46( . ) G02B 5/ 28( . ) H01L 21/ 20( . ) (86) International application number: PCT/GB1987/000891 (87) International publication number: WO 1988/004332 (16.06.1988 Gazette 1988/13)

(84) Designated Contracting States: CH DE FR LI NL (30) Priority: 09.12.1986 GB 19860029409 (71) Applicant: EVANS, Brian Langley Hampshire RG26 5LA (GB)	(72) Inventor: EVANS, Brian Langley Hampshire RG26 5LA (GB) (74) Representative: Cullis, Roger  Patents Department British Technology Group Ltd 101 Newington Causeway London SE1 6BU London SE1 6BU (GB)