Patent ID: 9599596
Date: 2017-03-21
CPC Classifications: G01N

Claim:
1. An optical sensor element comprising: at least one indicator composed of a luminescence-active agent; and at least one indicator protector, characterized in that the element comprises at least one indicator-bearing layer and at least one indicator protector-bearing layer, with the at least one indicator protector arranged in a layer of the element that faces towards a medium and the at least one indicator arranged in at least one different layer that is mounted facing away from the medium, wherein the element comprises i) an opaque first layer in contact with the medium, which is substantially free of indicators, ii) a second layer comprising the at least one indicator protector-bearing layer, which iia) is mounted on the side of the first layer that faces away from the medium, iib) contains indicator protectors, and iic) is substantially free of indicators, iii) a third layer comprising the at least one indicator-bearing layer, which iiia) is mounted on the side of the second layer that faces away from the medium, iiib) contains the indicators, and iiic) is substantially free of indicator protectors, wherein the indicator protectors are selected from a) reducing agents and/ or catalysts for the reduction of strong oxidants, b) adsorbents for chemisorption or physisorption of strong oxidants, or c) a combination of a) and b).