NOVELTY - The device has a cap or mirror body (10) formed in a gutter or tub-shape, and including a spherical cross-section. The body directs, deflects or diverts an incident light (L) on a photovoltaic absorber unit (20) e.g. solar cell plate. The absorber unit is arranged asymmetrical relative to a middle axis of the body and in a decentral or lateral region of the body. The body and/or the absorber unit is rotatable or bendable around an angle. An inclination angle or an orientation angle of the body and/or the absorber unit is adjustable based on a seasonal position of the sun.    USE - Concentrating device for use as a disk in an insulating glass system of a multi-glazed insulated glass window, a glass facade element, and a planar roof element of a shed and a winter garden, for concentrating an incident light i.e. sun light (all claimed), to provide glare, view and/or sun protection in inner and outer regions of a building.    ADVANTAGE - The photovoltaic absorber unit is arranged asymmetrical relative to the middle axis of the body and in the decentral or lateral region of the body, thus shadow-freely operating the absorber unit, ensuring simple electrical wiring, and reducing shadowing effects, and hence avoiding influence on a size of a proportion of the incident light by the shadowing effects. The device has a concentrator structure with a high efficiency and a high acceptance and tolerance angle, and ensures ideal alignment of the system for migration of the sun. The device reduces an installation depth below a mirror radius for less than 20 mm, increases a module efficiency and a transparency for more than 50 %, and aligns the acceptance and tolerance angle to sun migration.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a method for concentrating an incident light.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic sectional view of a concentrating device.    Facade (F)    Caustic curve (K)    Incident light (L)    Cap or mirror body (10)    Photovoltaic absorber unit (20)