Rain sensor for motor vehicle, has optical waveguide with coupling units, which are formed by layer-shaped pieces made of photopolymer, in which volume holograms are incorporated, where pieces are arranged between waveguide core and casing

摘要

The sensor has an optical waveguide (22), which can be arranged in a pane and includes a waveguide core (1), a waveguide casing (2) and planar holographic coupling units (3) for injecting and extracting radiation. The coupling units are formed by layer-shaped pieces made of photopolymer, in which volume holograms are incorporated. The photopolymer pieces are arranged between the core and casing. The photopolymer comprises a polymer matrix made of polymethyl methacrylate. Independent claims are also included for the following: (1) a method of creating a coupling unit for a rain sensor (2) a method of manufacturing a rain sensor.