Patent ID: 7860355

Claim:
An ATR-probe, comprising: a housing having an inner space with a media opening opening to outside of said housing, wherein said media opening is surrounded by an annular sealing surface; a transparent radiation guiding body closing said media opening and having two planparallel surfaces, between which light can be guided by means of total reflection, at least one sensitive section of a first surface of said planparallel surfaces is positioned in alignment with said media opening and can be contacted through said media opening with a medium to be measured, wherein said at least one sensitive section of said first surface is bordered by a sealing ring, which is arranged between said first surface and said sealing surface, wherein said transparent radiation guiding body is supported from said inner space by a support body; transmission light conductors, which extend in said inner space of said housing; and receiving light conductors, which extend in said inner space of said housing, wherein: light from said transmission light conductors can be coupled into said transparent radiation guiding body from the side of said transparent radiation guiding body facing away from said at least one sensitive section; adjoining said surface of said first planparallel surfaces, a first inclined deflection surface is provided, on which light coupled into said transparent radiation guiding body is deflected by total reflection in such a manner, that it hits first on a second surface of said planparallel surfaces, and can be guided in said radiation guiding body between said two planparallel surfaces by means of further total reflections; adjoining said first surface, opposite to said first inclined deflection surface, a second inclined deflection surface is provided, on which light guided between said two planparallel surfaces by means of total reflection impinges and is deflected by total reflection in such a manner, that it can then, on the side of said transparent radiation guiding body facing away from said at least one sensitive section, be coupled out of said transparent radiation guiding body and into said receiving light conductors; said first and said second inclined deflection surfaces are arranged in said inner space of said housing outside of the region surrounded by said sealing ring; the coupled light is not collimated; and the effective area of said transmission light conductors, from which light is coupled into said transparent radiation guiding body, is smaller than the effective area of said receiving light conductors, into which light from said transparent radiation guiding body is coupled.