| 摘要 |
An optical instrument is described in which a diffractive element (25) is located at a focal or image plane (3) of the instrument and the diffractive element (25) is effective to produce an array (6) of a plurality of exit pupils at a viewing position for the instrument and thereby to form an enlarged exit pupil for the instrument. The diffractive element is formed to provide a plurality greater than two of optical diffractive gratings each being disposed angularly relative to others of the plurality of optical diffractive gratings. <IMAGE> |
