(19)

(11)

EP 0 349 630 A1

(12)

(43) Date of publication: 10.01.1990 Bulletin 1990/02 (21) Application number: 89901363.0 (22) Date of filing: 14.12.1988

(51) International Patent Classification (IPC):  G09G 5/ 36( . ) G09G 5/ 393( . ) G06T 11/ 20( . ) (86) International application number: PCT/US1988/004417 (87) International publication number: WO 1989/006031 (29.06.1989 Gazette 1989/14)

(84) Designated Contracting States: DE FR GB (30) Priority: 18.12.1987 US 19870134773 (71) Applicant: DIGITAL EQUIPMENT CORPORATION Maynard Massachusetts 01754-1418 (US)	(72) Inventors: KELLEHER, Brian Mountain View, CA 94041 (US) FURLONG, Thomas, C. Half Moon Bay, CA 94019 (US) (74) Representative: Goodman, Christopher, et al  Eric Potter & Clarkson St. Mary's Court St. Mary's Gate Nottingham NG1 1LE Nottingham NG1 1LE (GB)