(19)

(11)

EP 4 158 158 A1

(12)

(43) Date of publication: 05.04.2023 Bulletin 2023/14 (21) Application number: 21729910.6 (22) Date of filing: 26.05.2021

(51) International Patent Classification (IPC):  E21F 17/18(2006.01) E02F 9/26(2006.01) (52) Cooperative Patent Classification (CPC): E02F 9/264; E21F 17/185 (86) International application number: PCT/FI2021/050377 (87) International publication number: WO 2021/240063 (02.12.2021 Gazette 2021/48)

(84) Designated Contracting States: AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR Designated Extension States: BA ME Designated Validation States: KH MA MD TN (30) Priority: 26.05.2020 FI 20205536 (71) Applicant: Aalto University Foundation sr 00076 Aalto (FI)	(72) Inventor: UOTINEN, Lauri 02660 Espoo (FI) (74) Representative: Berggren Oy  P.O. Box 16 Eteläinen Rautatiekatu 10A 00101 Helsinki 00101 Helsinki (FI)