| 摘要 |
<p>There is provided an apparatus comprising: means (11) for emitting scanning light to impinge on an optical system (7) under investigation; means (17, 47) for directing scanning light from said optical system (7) onto at least two pairs (20,22 and 21,23) of photoelectric converting elements; means (13,15,6) for scanning said scanning light over said optical system (7) and/or said converting elements; and determining means (9) for determining said refractive power or radius of curvature on the basis of the phase differences between the output signals of said converting elements in said pairs (20,22 and 21,23), characterized in that said means (13,15,6) for scanning is arranged to define beams of scanning light elongate in cross section with the elongate cross sections of the beams so defined being inclined at at least two angles of inclination relative to the direction of scanning and in that said apparatus comprises means (19) for providing to said determining means (9) a signal identifying said angle of inclination of the light beam scanning said optical system (7) and/or said converting elements. </p> |
