| 摘要 |
An arrangement for an optical instrument comprises two mirrors (11, 12) which co-act in illuminating an object or detecting light rays reflected by or emitted from the object. One mirror (11) is positioned adjacent the pupil of the instrument and the other (12) of the two mirrors is located in a position for directing transmitted light directly onto the first mentioned mirror (11) or a position for receiving directly light reflected by or emitted by the first mentioned mirror (11). The arrangement may have the form of a scanning device, in which case the first mentioned mirror (11) rotates about an axis (13) which is perpendicular to the symmetry axis (15) of the instrument, and the other (12) of the mirrors is arranged to rotate about an axis (14) which is perpendicular to the first mentioned axis. The distance (R) between the two mutually intersecting axes (13, 14) is equal to the mean distance between the centres of respective mirrors. The first mentioned mirror (11) moves at a frequency within the range of 25-50 Hz, whereas the other mirror (12) moves at a frequency within the range of 0.1-0.3 Hz. |
