(19)

(11)

EP 1 815 294 A2

(12)

(88) Date of publication A3: 22.03.2007 (43) Date of publication: 08.08.2007 Bulletin 2007/32 (21) Application number: 05791381.6 (22) Date of filing: 11.10.2005

(51) International Patent Classification (IPC):  G03F 7/20(2006.01) (86) International application number: PCT/GB2005/003918 (87) International publication number: WO 2006/056730 (01.06.2006 Gazette 2006/22)

(84) Designated Contracting States: AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC NL PL PT RO SE SI SK TR Designated Extension States: AL BA HR MK YU (30) Priority: 26.11.2004 GB 0426036 (71) Applicant: The BOC Group plc Windlesham Surrey GU20 6HJ (GB)	(72) Inventor: GRANT, Robert Bruce Crawley, West Sussex RH10 2LW (GB) (74) Representative: Booth, Andrew Steven  Edwards Limited Manor Royal Crawley West Sussex RH10 2LW Crawley West Sussex RH10 2LW (GB)