| Popis: |
Aspheric surfaces are widely used in aerospace sensing optic instruments. There are numerous reflecting optical system designs that call for oblate elliptical surfaces, such as secondary mirror or tertiary mirror in three mirror anastigmat (TMA). The consequence brought by increase in field of view (FOV) and speed of optical system is the decrease in F/# of aspheric surface which makes its production harder. Due to oblate ellipsoid's stigmatic points are not lined up on the optic axis, null lenses corrector is used more often than the stigmatic null test especially in low F/# aspheric surfaces test. Three types of null lenses tests for an oblate elliptical surface with aperture Φ360mm, F/0.8, conic=0.243 are presented including a new type which is modified by replacing the reference flat and null lens with one lens with reflect surface. Furthermore, sensitivity tolerances for each design are practiced. |
