Optical switching device comprising - precisely one polarisation layer, where the polarisation layer linearly polarises light, and - a switching layer arranged parallel to the polarisation layer, comprising a liquid-crystalline material comprising at least one dichroic dye, where the at least one dichroic dye is selected from azo compounds, anthraquinones, benzothiadiazoles, diketopyrrolopyrroles and rylenes and the total proportion of the dichroic dyes in the liquid-crystalline material is 0.1% by weight to 15% by weight, and where the liquid-crystalline material has a clearing point above 80°C and comprises a compound of a formula where R 1 is selected from alkyl groups having 1 to 10 C atoms, where the switching layer has a thickness between 2 μm and 50 μm and a dark switching state having low transmission through the switching layer and a bright switching state having high transmission through the switching layer, where the absorption axis of the polarisation layer in the dark switching state of the switching layer is arranged at an angle of 85° - 95° to the principal axis of absorption of the at least one dichroic dye, where the light transmittance T v, in accordance with the EN410 standard, of the switching layer in the dark switching state of the device for light which is polarised parallel to the principal axis of absorption of the at least one dichroic dye is less than 3%, and where the switching device has the layer sequence - the polarisation layer - substrate layer - electrically conductive transparent layer - alignment layer - the switching layer comprising the liquid-crystalline material comprising the at least one dichroic dye - alignment layer - electrically conductive transparent layer - substrate layer, where the polarisation layer is arranged between a light source and the switching layer. - precisely one polarisation layer, where the polarisation layer linearly polarises light, and - a switching layer arranged parallel to the polarisation layer, comprising a liquid-crystalline material comprising at least one dichroic dye, where the at least one dichroic dye is selected from azo compounds, anthraquinones, benzothiadiazoles, diketopyrrolopyrroles and rylenes and the total proportion of the dichroic dyes in the liquid-crystalline material is 0.1% by weight to 15% by weight, and where the liquid-crystalline material has a clearing point above 80°C and comprises a compound of a formula where R 1 is selected from alkyl groups having 1 to 10 C atoms, where the switching layer has a thickness between 2 μm and 50 μm and a dark switching state having low transmission through the switching layer and a bright switching state having high transmission through the switching layer, where the absorption axis of the polarisation layer in the dark switching state of the switching layer is arranged at an angle of 85° - 95° to the principal axis of absorption of the at least one dichroic dye, where the light transmittance T v, in accordance with the EN410 standard, of the switching layer in the dark switching state of the device for light which is polarised parallel to the principal axis of absorption of the at least one dichroic dye is less than 3%, and where the switching device has the layer sequence where R 1 is selected from alkyl groups having 1 to 10 C atoms, where the switching layer has a thickness between 2 μm and 50 μm and a dark switching state having low transmission through the switching layer and a bright switching state having high transmission through the switching layer, where the absorption axis of the polarisation layer in the dark switching state of the switching layer is arranged at an angle of 85° - 95° to the principal axis of absorption of the at least one dichroic dye, where the light transmittance T v, in accordance with the EN410 standard, of the switching layer in the dark switching state of the device for light which is polarised parallel to the principal axis of absorption of the at least one dichroic dye is less than 3%, and where the switching device has the layer sequence - the polarisation layer - substrate layer - electrically conductive transparent layer - alignment layer - the switching layer comprising the liquid-crystalline material comprising the at least one dichroic dye - alignment layer - electrically conductive transparent layer - substrate layer,