Patent ID: 7293886

Claim:
A device for an optical system ( 1 ) that works with an intermediate image and comprises: a stop ( 5 ) with an associated aperture ( 6 ) through which light passes completely through the device, a light-reducing or light-absorbing arrangement located along a side of the aperture ( 6 ), said arrangement being arranged to reduce considerably or eliminate completely light ( 11 , 18 ) incident to the side of the aperture, and thereby reduce or eliminate stray light and reflections, characterized in that in the case with the reflection of the light, a surface arrangement is arranged with its surfaces at an angle to each other that results in reflection in a controlled direction or directions, characterized in that the surface arrangement comprises at least two different surfaces or surface arrangements arranged to produce at least two or three reflections of the light ( 11 , 18 ) incident to the side of the aperture ( 6 ), characterized in that the light-reflecting or light-absorbing arrangement comprises a first part ( 20 ) that is arranged with the said aperture ( 6 ) and with one or more external first light-reflecting surfaces ( 14 ′) an a second part ( 21 ) that has one or more internal second light-reflecting surfaces ( 13 ′), and characterized in that one or more first light-reflecting surfaces are in the shape of outer cones and one or more second light-reflecting surfaces are in the shape of inner cones, the half cone angles for the surfaces being unequal.