Arrangement for fluorescence-optical measurement of concentrations of substances contained in a sample
First Claim
1. An arrangement for fluorescence-optical measurement of concentrations of substances contained in a sample, said arrangement being used in a surrounding ambient medium, comprising a light source for excitation radiation, a sensor element fluorescing upon excitation in accordance with substance concentration to be determined, and a detector for emission radiation, said sensor element comprising a carrier element which comprises at least two parallel surfaces and which is transparent for said excitation radiation and said emission radiation, said sensor element having a refractive index n1 that is higher than the refractive index n3 of a prevailing ambient medium, at least part of one of said surfaces of said carrier element being covered with a layer of an indicator substance of a given refractive index n2, whose side facing away from said carrier element is in contact with said sample during the process of measurement, said excitation radiation having angles of incidence α
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1, measured from the normal on the boundary surface between said carrier element and said ambient medium, which are bigger than α
G.sbsb.1,3 =arc sin n3 /n1, so that said excitation radiation is propagated in said carrier element by total reflection and wherein said excitation radiation has angles α
1 smaller than α
G.sbsb.1,2 =arc sin n2 /n1 in that area of said carrier element which is in contact with said sample via the indicator layer.
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Accused Products
Abstract
An arrangement for the fluorescence-optical measurement of concentrations of substances contained in a sample includes a detector, a light source and a sensor element that includes a carrier element, the carrier element having an indicator layer on a portion thereof and an indicator-free surface, the carrier element being transparent to the radiation used, and having a refractive index which is greater than that of the ambient medium at the indicator-free surface, the light space being positioned such that the transmission of light from the light source to the indicator layer, and from there to the detector, is achieved, at least partially, by total reflection in the carrier element.
23 Citations
13 Claims
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1. An arrangement for fluorescence-optical measurement of concentrations of substances contained in a sample, said arrangement being used in a surrounding ambient medium, comprising a light source for excitation radiation, a sensor element fluorescing upon excitation in accordance with substance concentration to be determined, and a detector for emission radiation, said sensor element comprising a carrier element which comprises at least two parallel surfaces and which is transparent for said excitation radiation and said emission radiation, said sensor element having a refractive index n1 that is higher than the refractive index n3 of a prevailing ambient medium, at least part of one of said surfaces of said carrier element being covered with a layer of an indicator substance of a given refractive index n2, whose side facing away from said carrier element is in contact with said sample during the process of measurement, said excitation radiation having angles of incidence α
-
1, measured from the normal on the boundary surface between said carrier element and said ambient medium, which are bigger than α
G.sbsb.1,3 =arc sin n3 /n1, so that said excitation radiation is propagated in said carrier element by total reflection and wherein said excitation radiation has angles α
1 smaller than α
G.sbsb.1,2 =arc sin n2 /n1 in that area of said carrier element which is in contact with said sample via the indicator layer. - View Dependent Claims (2, 3)
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1, measured from the normal on the boundary surface between said carrier element and said ambient medium, which are bigger than α
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4. An arrangement for fluorescence-optical measurement of concentrations of substances contained in a sample, said arrangement being used in a surrounding ambient medium, comprising a light source for excitation radiation, a sensor element fluorescing upon excitation in accordance with substance concentration to be determined, and a detector for emission radiation, said sensor element comprising a carrier element which comprises at least two parallel surfaces and which is transparent for said excitation and said emission radiation, said sensor element having a refractive index n1 that is higher than the refractive index n3 of a prevailing ambient medium, at least part of one of said surfaces of said carrier element being covered with a layer of an indicator substance of a given refractive index n2, whose side facing away from said carrier element is in contact with said sample during the process of measurement, said excitation radiation having angles of incidence α
-
1, measured from the normal on the boundary surface between said carrier element and said indicator substance, which are smaller than α
G.sbsb.1,2 =arc sin n2 /n1 in that area of said carrier element which is in contact with said sample via the indicator layer and wherein said emission radiation reaching said detector has angles α
1 bigger than α
G.sbsb.1,3 =arc sin n3 /n1, so that said emission radiation is propagated in said carrier element by total reflection. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12, 13)
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1, measured from the normal on the boundary surface between said carrier element and said indicator substance, which are smaller than α
Specification