(19)

(11)

EP 0 876 678 A1

(12)

(43) Date of publication: 11.11.1998 Bulletin 1998/46 (21) Application number: 96901061.0 (22) Date of filing: 25.01.1996

(51) International Patent Classification (IPC):  H01J 43/ 04( . ) (86) International application number: PCT/GB1996/000178 (87) International publication number: WO 1997/027615 (31.07.1997 Gazette 1997/33)

(84) Designated Contracting States: AT BE CH DE DK ES FR GB GR IE IT LI NL PT SE (71) Applicant: ERA PATENTS LIMITED Leatherhead Surrey KT22 7SA (GB)	(72) Inventors: WESTLAND, Duncan James Woking, Surrey GU21 4UF (GB) SKARDA, Vladimir Ashtead, Surrey KT21 1NW (GB) (74) Representative: Rackham, Stephen Neil  GILL JENNINGS & EVERY, Broadgate House, 7 Eldon Street London EC2M 7LH London EC2M 7LH (GB)