US 12,405,221 B2
Optochemical sensor and method for measured value correction
Andreas Löbbert, Waldheim (DE)
Assigned to Endress+Hauser Conducta GmbH+Co. KG, Gerlingen (DE)
Filed by Endress+Hauser Conducta GmbH+Co. KG, Gerlingen (DE)
Filed on Apr. 16, 2024, as Appl. No. 18/636,691.
Application 18/636,691 is a continuation of application No. 17/225,210, filed on Apr. 8, 2021, granted, now 11,971,360.
Claims priority of application No. 10 2020 109 901.0 (DE), filed on Apr. 8, 2020.
Prior Publication US 2024/0264086 A1, Aug. 8, 2024
This patent is subject to a terminal disclaimer.
Int. Cl. G01N 21/77 (2006.01); G01N 21/27 (2006.01); G01N 21/64 (2006.01)
CPC G01N 21/77 (2013.01) [G01N 21/274 (2013.01); G01N 21/6428 (2013.01); G01N 21/645 (2013.01); G01N 2021/6432 (2013.01); G01N 2021/6439 (2013.01); G01N 2021/6484 (2013.01); G01N 2021/772 (2013.01)] 16 Claims
OG exemplary drawing
 
1. An optochemical sensor for determining a measurement signal that correlates with a physical or chemical measurand of a measuring fluid, the sensor comprising:
a housing including at least one immersion region configured to be immersed in the measuring fluid;
a removable sensor cap including a sensor spot,
wherein the sensor cap is disposed in the immersion region of the housing, and
wherein the sensor spot is disposed on a lateral surface of the sensor cap and comprises:
an analyte-sensitive indicator dye, a luminescence of which is affected by an analyte in the measuring fluid;
a hydrophobic matrix; and
a state description indicator contained within the hydrophobic matrix,
wherein the state description indicator is selected to absorb a polar solvent of the measuring fluid and to undergo a change of luminescence decay behavior or phase angle or a change of absorption and/or emission bands in presence of the polar solvent such that, when the polar solvent is absorbed into the hydrophobic matrix via cracks in the hydrophobic matrix, the cracks are detectable, wherein the cracks reflect an aging state of the sensor spot;
at least one radiation source disposed in the housing and configured to radiate excitation radiation onto the sensor spot, to excite the luminescence of the indicator dye, and to excite a luminescence of the state description indicator;
a first radiation receiver configured to receive reception radiation emitted by the sensor spot;
a second radiation receiver configured to receive excitation radiation from the at least one radiation source after passing through the sensor spot; and
a sensor circuit disposed in the housing and electrically connected to the at least one radiation source and the first and second radiation receivers, wherein the sensor circuit is configured to:
control the at least one radiation source;
generate, based on an intensity of luminescence and/or a phase angle of luminescence of the indicator dye detected by the first radiation receiver, a measurement signal representing the physical or chemical measurand in the measuring fluid in contact with the sensor spot; and
based on the change of luminescence decay behavior or phase angle or the change of absorption and/or emission bands of the state description indicator in the presence of the polar solvent, detect the cracks in the hydrophobic matrix and thereby determine the aging state of the sensor spot.