(19)

(11)

EP 0 131 004 A1

(12)

(43) Date of publication: 16.01.1985 Bulletin 1985/03 (21) Application number: 84900094.0 (22) Date of filing: 16.12.1983

(51) International Patent Classification (IPC):  H01L 23/ 12( . ) H01L 23/ 047( . ) H01L 23/ 02( . ) H01L 23/ 66( . ) (86) International application number: PCT/GB1983/000336 (87) International publication number: WO 1984/002612 (05.07.1984 Gazette 1984/16)

(84) Designated Contracting States: AT BE CH DE FR LI LU NL SE (30) Priority: 24.12.1982 GB 19820036783 (71) Applicant: PLESSEY OVERSEAS LIMITED Ilford Essex IG1 4AQ (GB)	(72) Inventor: SPARROW, John, Andrew Nr. Towcester Northampton (GB) (74) Representative: Field, Howard John  The Plessey Company plc Beeston Nottingham, NG9 1LA Nottingham, NG9 1LA (GB)