| 摘要 |
PURPOSE:To detect rainfall, dew condensation, water drop scattering, etc. without being influenced by the presence of ionic materials by utilizing the variation in the reflectivity and transmissivity or the color tone of light at dried and wetted times of a hydrophilic porous film. CONSTITUTION:A hydrophilic porous film is opaque at drying time, but clarified from the opaque state by wetting. Light is emitted to said film by utilizing said property thereof to detect the adhered water drops due to the variation in light reflectivity and transmissivity or the color tone. Said film is formed so that water drops are diffused into the film in wide ranges by a capillary phenomenon in case the water drops are adhered on the surface thereof. <=75 deg. contact angle with water is preferable. As instances of said film, various materials such as hydrophobic polymer subjected to surface treatment by a surfactant, polymer having hydrophilic properties by sulfonation of polystylene, etc. are listed up. |
