Optical sensor for detecting an analyte in a fluid, comprises a sensor layer as light conductor for light of frequency range, and/or a surface present over the sensor layer and accessibly made as sensitive area of the fluid

The optical sensor for detecting an analyte in a fluid, comprises a sensor layer (11) as light conductor for light of frequency range, and/or a surface (18) present over the sensor layer and accessibly made as sensitive area of fluid. The sensor layer is present on an analyte subjected over the surface and an optical characteristic of the sensor layer is modulatable for light (20) directed in the sensor layer in dependent on the presence of the analyte. The sensor layer comprises a luminescent color material that emits light in named frequency range. The optical sensor for detecting an analyte in a fluid, comprises a sensor layer (11) as light conductor for light of frequency range, and/or a surface (18) present over the sensor layer and accessibly made as sensitive area of fluid. The sensor layer is present on an analyte subjected over the surface and an optical characteristic of the sensor layer is modulatable for light (20) directed in the sensor layer in dependent on the presence of the analyte. The sensor layer comprises a luminescent color material that emits light in named frequency range at lateral radiation of an excitation radiation (21), and/or a radiation surface (19) is provided in an interval to the area of the lateral radiation. On the radiation surface, light directed in the sensor layer is coupled to measuring purposes. The radiation surface is assigned a radiation structure, which radiates the light directed in the sensor layer in the form of a lateral radiation through the radiation surface lying at the side of the sensor. The radiation structure is formed as locally limited layer of a material arranged on the sensor layer. The material scatters the light in the sensor layer for side. A light source that is subjected on a side surface of the sensor, oppositively lies the sensitive area. The light source has a luminous area that immigrates the sensor and is oriented parallel to the sensor layer. The radiating of the excitation radiation is carried out on the side on which the radiation surface lies. The radiation surface lies at a side of the sensor oppositively lying to the sensitive surface. The sensor layer comprises an indicator for the analyte, different from the luminescent color material. The indicator modulates the optical characteristic of the sensor layer in contact with analytes subjected over the surface.