(19)

(11)

EP 0 087 411 A1

(12)

(43) Date of publication: 07.09.1983 Bulletin 1983/36 (21) Application number: 81902537.0 (22) Date of filing: 04.09.1981

(51) International Patent Classification (IPC):  C03B 37/ 027( . ) G02B 6/ 028( . ) (86) International application number: PCT/US1981/001184 (87) International publication number: WO 1983/000857 (17.03.1983 Gazette 1983/07)

(84) Designated Contracting States: DE FR GB (71) Applicant: TRW INC. Elk Grove Village Illinois 60007 (US)	(72) Inventor: HODGE, Malcolm Hellyer Wyncote, PA 19095 (US) (74) Representative: Wilson, Nicholas Martin, et al  WITHERS & ROGERS 4 Dyer's Buildings Holborn London EC1N 2JT London EC1N 2JT (GB)