(19)

(11)

EP 0 550 427 A1

(12)

(43) Date of publication: 14.07.1993 Bulletin 1993/28 (21) Application number: 90911629.0 (22) Date of filing: 03.08.1990

(51) International Patent Classification (IPC):  G06F 15/ 80( . ) (86) International application number: PCT/GB1990/001209 (87) International publication number: WO 1992/002882 (20.02.1992 Gazette 1992/05)

(84) Designated Contracting States: DE GB (71) Applicant: DU PONT PIXEL SYSTEMS LIMITED Stevenage Hertfordshire SG1 4QN (GB)	(72) Inventors: NEAVE, John Walter Dorking, Surrey RH5 5EX (GB) TREVETT, Neil Francis Kingston-Upon-Thames, Surrey KT13 0RJ (GB) (74) Representative: Targett, Kenneth Stanley  D. Young & Co., 21 New Fetter Lane London EC4A 1DA London EC4A 1DA (GB)