Abstract: A method and device is described for compensating ambient temperature dependent magnification and focus change of a zoom lens system, whereby an ambient temperature compensation structure cooperates with a rotational ring and an optical-element adjusting member such that a phase variation between the rotational ring and the optical-element adjusting member in response to an ambient temperature change is compensated and whereby the phase variation characterizes an optical property of the zoom lens system such as magnification or focus.

Abstract: An optical design is described to be used in a color projection system. The system comprises a white light source (52), a light splitting means to split the white beam into color subbeams, optical components to direct each color subbeam on a light modulating means (56) and a dichroic prism (70). The light splitting means and the optical components are arranged such that each of the images of the color subbeams imaged on the light modulating means (56) has equal size and orientation, i.e. such that the magnification of the color subimage on the light modulating means (56) is equal. This is obtained by providing equal light paths for each color subbeam or by providing optical components such that either all different color images on the screen are inverted or none of the different color images are inverted.

Abstract: A system and method for fixing a projection lens 102 and adjusting the position of a projection lens 102 is provided, which is compact and has a high precision. The projection lens 102 is positioned on a base plate 104. The position of the projection lens can be adjusted by providing possibilities for horizontal and vertical shift in a plane perpendicular to the optical axis of the projection lens 102. This is performed by actuating three points of the base plate 104. Furthermore, by providing further shifting means at the three points of the base plate 104, tilting of the projection lens can be performed, thus providing Scheimpflug correction. In this way, motion of the projection lens in five degrees of freedom is provided by actuating three points at a base plate 104 whereon a projection lens 102 can be easily mounted and removed.