Abstract: An optical device includes first and second optical elements rotatable with respect to each other around a geometric optical axis of the optical device. The first optical element includes a first surface for modifying a distribution of light exiting the first optical element, and the second optical element includes a second surface facing towards the first surface and for further modifying the distribution of the light. One of the first and second surfaces includes convex areas whereas the other one of these surfaces includes concave areas so that an optical effect of the optical device is changeable by rotating the first and second optical elements with respect to each other. The first and second optical elements include sliding surfaces for mechanically supporting the second optical element with respect to first optical element in radial directions perpendicular to the geometric optical axis.

Abstract: An optical device includes a reflector-section that includes a light-ingress surface for receiving light from a light source, a reflector surface for reflecting the light based on total internal reflection, and a light-egress surface through which the reflected light exits the optical device. When the light source is at a predetermined position with respect to the optical device, an angle of incidence (?i) of the light at the light-egress surface is a polarization angle at which a p-polarized component of the light is transmitted through the light-egress surface without being reflected by the light-egress surface. Thus, unwanted reflections at the light-egress surface can be reduced and thereby unwanted scattering of light is reduced while having good transmitting efficacy.

Abstract: An optical device includes a reflector-section that includes a light-ingress surface for receiving light from a light source, a reflector surface for reflecting the light based on total internal reflection, and a light-egress surface through which the reflected light exits the optical device. When the light source is at a predetermined position with respect to the optical device, an angle of incidence (?i) of the light at the light-egress surface is a polarization angle at which a p-polarized component of the light is transmitted through the light-egress surface without being reflected by the light-egress surface. Thus, unwanted reflections at the light-egress surface can be reduced and thereby unwanted scattering of light is reduced while having good transmitting efficacy.