公开(公告)号：EP1518095A1

公开(公告)日：2005-03-30

申请号：EP03732738.4

申请日：2003-06-19

Applicant: Qinetiq Limited

Inventor： BEALE,J.E.PQinetiQ,Malvern Tech.Cen.Bldg.KXRM.9 ,  HARVEY,A.RSchool of Engineering&Physical Sciences ,  FLETCHER-HOLMES,D.W.School of Eng.&Phys.Sciences

IPC: G01J3/28 ,  G01J3/453

CPC classification number: G01J3/4537 ,  G01J3/0205 ,  G01J3/2823

Abstract: The present invention relates to an imaging apparatus and comprises input and output polarisers (20,28), a first polarising beam splitter (22) and at least one additional polarising beam splitter (24), a light sensitive detector (30) and focussing means (26) arranged on an axis. The input polariser (20) resolves incident light into a single linear polarisation state. The first polarising beam splitter (22) receives light from the input polarises (20), and resolves it into equal magnitude orthogonally polarised rays which are mutually spaced and have a path difference therebetween. The or each additional polarising beam splitter (24) is arranged to receive light from the first polarising beam splitter (22). The transmission axis of the output polariser (28) is parallel to or perpendicular to the transmission axis of the input polarises (20) to resolve the orthogonally polarised light rays having past through the or each additional polarising beam splitter (24) into the same or perpendicular polarisation state as light resolved by the, first polariser (20). The first polarising beam splitter (22), the or each additional polarising beam splitter (24) and the focussing means (26) are mutually spaced such that said mutually spaced rays are brought to coincidence whereby interference fringes are produced, the detector (30) being arranged to detect the interference fringes. One beam splitter (24) is mounted for movement perpendicular to said axis, whereas the other beam splitter(s) (22) is/are rigidly mounted against movement.