Rain sensor for use in motor vehicle, has waveguide core comprising side region in detecting section, where side region adjoins at material with refractive index, which is larger than another refractive index

摘要

The sensor has a waveguide (4) comprising a waveguide core and two cladding layers, where the cladding layers are provided on two opposite sides of the waveguide core that has a refractive index. The cladding layers have another refractive index, which is smaller than the former refractive index. The waveguide core has a side region in a detecting section (5). The side region adjoins at a material i.e. sol-gel material, with a third refractive index, which is larger than the latter refractive index.