公开(公告)号：US3819940A

公开(公告)日：1974-06-25

申请号：US36772173

申请日：1973-06-07

Applicant: HAWKER SIDDELEY DYNAMICS LTD

Inventor： LAWS A

IPC: G01J1/04 ,  G01J1/42 ,  G01S3/781 ,  G02B6/06 ,  G02B6/08 ,  G02B27/00 ,  G02B5/14

CPC classification number: G02B6/08 ,  G01J1/0209 ,  G01J1/04 ,  G01J1/0411 ,  G01J1/0425 ,  G01J1/4228 ,  G01S3/781 ,  G02B6/06

Abstract: An optical instrument wherein an optical signal is projected on to a sensor array or sensitive medium and angular deflections of the path of the optical signal about an instrument signal source as centre appear as displacements from a datum lying in the general plane of the sensor array or sensitive medium, the instrument having an optical axis passing through said source and normal to said plane, characterized in that, to correct for the tangent law error that would otherwise arise, a correcting optical device is interposed in the signal path and has its surface receiving the signal curved, in the concave sense, about a centre lying on or intersecting the optical axis of the instrument, the curvature being of radius R, where R is greater than the distance t from said instrument signal source to the point in said curved surface that lies on said optical axis, the surface of the correcting optical device facing the sensor array being plane.