(19)

(11)

EP 0 845 154 A1

(12)

(43) Date of publication: 03.06.1998 Bulletin 1998/23 (21) Application number: 96931379.0 (22) Date of filing: 12.08.1996

(51) International Patent Classification (IPC):  H01J 63/ 06( . ) (86) International application number: PCT/US1996/013091 (87) International publication number: WO 1997/007531 (27.02.1997 Gazette 1997/10)

(84) Designated Contracting States: DE ES FR GB IT (30) Priority: 14.08.1995 US 19950602262 (71) Applicants: E.I. DU PONT DE NEMOURS AND COMPANY Wilmington Delaware 19898 (US) THE REGENTS OF THE UNIVERSITY OF CALIFORNIA Oakland, CA 94612-3550 (US)	(72) Inventors: SILZARS, Aris, Kenneth Issaquah, WA 98029 (US) SPRINGER, Robert, William Los Alamos, NM 87544 (US) (74) Representative: Jones, Alan John  CARPMAELS & RANSFORD 43 Bloomsbury Square London, WC1A 2RA London, WC1A 2RA (GB)