Abstract: In a projection system for projecting a video picture composed of picture points on a screen with at least one light source which emits a light bundle and can be varied in intensity and with a deflecting device which deflects the light bundle to illuminate the picture points on the screen, a transformation optical system having at least two stages is arranged between the deflecting device and the screen and is corrected according to the tangent condition so as to be free of distortion. The transformation optical system has at least two optical stages. The first optical stage produces an intermediate image plane which is imaged on the screen by means of the subsequent optical stage (s).

Abstract: The invention relates to a device for positioning an object relative to a carrier means, particularly for use in digital image conversion where an object has to be accurately positioned relative to the carrier means. This is achieved by tensioning said object by means of two strips and an elongated member to a mounting piece which moved by a displacement means positions said object. The positioning operation is observed through a measuring microscope.