| 摘要 |
This cranked infrared bifocal optical system fulfils the functions of focus changing (long focal length, short focal length), of temperature focusing and of finite-distance focusing. It consists of three lenses L1, L2, L3 and of a mirror M in order to crank the beam. The lens L2 is tilted about the mirror M in order to switch over the system from long or short focal lengths, whereas the lens L3 is moved translationally for temperature-focusing or finite-distance focusing corrections. The beam can be oriented by means of the mirror M and, additionally, by means of the lens L2. <IMAGE>
|
