| abstract |
A focusing-device for the radiation from a light source ( 2 ) is provided with a collector mirror ( 1, 1 ′) which is arranged in a mount ( 24 ) and collects the light, in virtual or real terms, from the light source ( 2 ) at the second focus ( 200 ). The collector mirror ( 1, 1 ′) is displaceably connected to the mount ( 24 ) via a bearing in such a way that its optical properties remain at least approximately the same even in the event of temperature changes. |