| abstract |
In order for an arrangement for the optical measurement of physical quantities as well as substance concentrations, consisting of a light measuring device with at least one radiation source, a monochromator, a light receiver and a display device and at least one space that can be measured by the light measuring device and is delimited by a substance and that is related to the material to be measured contains physical size with a color change reacting indicator substance, to improve the freedom of reaction of the membrane and the measurement object on the measured value, the absorption and the layer thickness of the indicator is chosen such that the penetration depth of the test light is smaller than the thickness of the indicator space. |