Optical element

An optical element comprising

• a substantially plate-shaped or shell-shaped substrate with a first large surface and a second large surface, wherein one of the large surfaces acts as light entry surface for light incident on the optical element and the other large surface acts as light exit surface for light incident on the optical element,
• a plurality of opaque surfaces near or on the first large surface,
• in a first alternative, a plurality of surfaces near or on the second large surface which are switchable between an opaque state and a transparent state or, in a second alternative, a plurality of chambers in the substrate which are filled with a fluid, wherein the fluid contains up to 30 volume percent of electrophoretically or magnetophoretically movable particles which absorb light of one or more wavelengths or wavelength ranges and which can be localized in at least two different states inside of the respective chambers by a variable electromagnetic field,
• wherein, in the first alternative, a switchable surface lies in each instance above an opaque surface in a projection direction perpendicular to the substrate, and wherein, in the second alternative, a chamber lies in each instance above an opaque surface in a projection direction perpendicular to the substrate,
• so that, in a first state in which, in the first alternative, the switchable surfaces are in the opaque state and in which, in the second alternative, more than one half of all of the particles are located in that one half of the corresponding chambers that is remote of the first large surface, the optical element limits the propagation directions of light which impinges on the light entry surface,
• and so that, in a second state in which, in the first alternative, the switchable surfaces are in the transparent state and in which, in the second alternative, more than one half of all of the particles are located in that one half of the corresponding chambers that faces the first large surface, the optical element does not limit the propagation directions of light impinging on the light entry surface but, rather, merely does not transmit a portion of the light because of the opaque surfaces.