(19)

(11)

EP 0 823 072 A1

(12)

(43) Date of publication: 11.02.1998 Bulletin 1998/07 (21) Application number: 96903148.0 (22) Date of filing: 23.02.1996

(51) International Patent Classification (IPC):  G03F 7/ 20( . ) G03F 7/ 30( . ) (86) International application number: PCT/GB1996/000421 (87) International publication number: WO 1996/026467 (29.08.1996 Gazette 1996/39)

(84) Designated Contracting States: DE GB (71) Applicant: COUNCIL FOR THE CENTRAL LABORATORY OF THE RESEARCH COUNCILS Chilton Didcot, Oxfordshire OX11 0QX (GB)	(72) Inventors: TURCU, Ion, Christian, Edmond Oxfordshire OX12 8HE (GB) MANN, Christopher, Mark Oxfordshire SN7 7H (GB) MADDISON, Brian, James Oxfordshire OX14 1QY (GB) (74) Representative: Perkins, Sarah  Stevens, Hewlett & Perkins 1 Serjeants' Inn Fleet Street London EC4Y 1LL London EC4Y 1LL (GB)