Optical sensor element, optical oxygen sensor and method for monitoring the function of an optical oxygen sensor

Abstract

The present invention relates to an optical sensor element, an optical oxygen sensor and a method for monitoring the function of an optical oxygen sensor. The optical chemical sensor element comprises: - a substrate layer having a first substrate side facing a measurement medium and a second substrate side opposite to the first substrate side; - a functional layer arranged on the first substrate side and subdivided into at least two functionally separate functional sections, wherein a first functional section has a second reference dye and a second functional section has an indicator dye, wherein the second reference dye comprises an organic material and is not sensitive to oxygen and is adapted to emit a second luminescence signal upon stimulation with a first stimulation signal, wherein the indicator dye comprises an organic material and is sensitive to oxygen and is adapted to emit a third luminescence signal upon stimulation with the first stimulation signal, wherein the substrate layer is transparent to the stimulation signal and to the second and third luminescence signals.

Description

Technical Field

[0001] This invention relates to an optical sensor element, an optical oxygen sensor, and a method for monitoring the function of the optical oxygen sensor. Background Technology

[0002] In industrial applications such as environmental analysis in food technology, biotechnology, and pharmaceuticals, especially in water management and for highly variable laboratory applications, the concentration of measured variables such as pH, conductivity, or even analytes such as ions or dissolved gases in the gaseous or liquid measurement medium is crucial. For example, these measured variables can be identified and / or monitored using electrochemical sensors such as optical, potential, current, voltammetric, or coulometric sensors, or even conductivity sensors.

[0003] Optical oxygen sensors are sensors based on photochemical reactions with the measurement medium. Typically, these sensors contain a luminescent material suitable for emitting light when the material is stimulated by a light source. This luminescent material is also sensitive to oxygen, such that the light emitted by the luminescent material is affected by the oxygen content of the measurement medium.

[0004] DE 198 29 657 A1 discloses a known method and apparatus for referencing a luminescence intensity signal in oxygen measurements. US Patent 6,602,716 B1 describes a DLR (Dual Lifetime Reference) method for pH measurements.

[0005] Known problems with previous optical oxygen sensors include temperature dependence and low drift stability. Temperature dependence is caused by the measurement medium and can therefore be controlled if the oxygen sensor is only used in a specific application range (e.g., below 80°C). Oxygen sensor drift can be caused, for example, by photobleaching of analyte-sensitive indicator dyes or disinfectants, leading to distortion of the oxygen sensor's measurements. Summary of the Invention

[0006] Therefore, the object of the present invention is to realize an optical oxygen measurement that can be reliably and simply implemented.

[0007] According to the present invention, this objective is achieved by the photochemical sensor element according to claim 1.

[0008] The photochemical sensor element for a photochemical oxygen sensor according to the present invention comprises:

[0009] - A substrate layer having a first substrate side facing the measurement medium and a second substrate side opposite to the first substrate side;

[0010] - A functional layer, disposed on the first substrate side and subdivided into at least two separate functional sections.

[0011] The first functional segment contains a second reference dye, and the second functional segment contains an indicator dye.

[0012] The second reference dye comprises organic materials and is insensitive to oxygen, and is adapted to emit a second luminescent signal when stimulated with a first stimulus signal.

[0013] The indicator dye comprises an organic material and is sensitive to oxygen, and is adapted to emit a third luminescent signal upon stimulation with the first stimulus signal.

[0014] The substrate layer is transparent to the stimulation signal, the second emission signal, and the third emission signal.

[0015] Using the photochemical sensor element according to the invention, the drift of the sensor can be detected and quantified in order to compensate the measurement value determined by the sensor relative to the determined drift. Since the photochemical sensor element has an oxygen-insensitive reference dye, the drift of the indicator dye, for example due to free radicals, such as singlet oxygen, can be detected by comparing the luminescence signal emitted by the reference dye with the luminescence signal of the indicator dye. With the photochemical sensor element according to the invention, the drift of the photochemical oxygen sensor can be checked during continuous operation and the current measurement value can be compensated based on the detected drift. Thus, the photochemical oxygen sensor does not need to be removed from the measurement point to determine the drift of the oxygen sensor using a medium with a known oxygen content. The workload of operating the oxygen sensor is thus minimized, and the quality of the measurement results is maximized simultaneously. The drift caused by photobleaching can be indicated by the reference indicator. The so-called "τ-zero value," i.e., the decay time when no analyte is present in the photochemical sensor, can thus be corrected by in-situ adjustment.

[0016] According to one embodiment of the present invention, the first functional segment further comprises a first reference dye, wherein the first reference dye comprises an inorganic material and is insensitive to oxygen, and is adapted to emit a first luminescent signal when stimulated with the first stimulus signal.

[0017] According to one embodiment of the present invention, the functional layer further includes a third functional segment having a first reference dye, wherein the first reference dye comprises an inorganic material and is insensitive to oxygen, and is adapted to emit a first luminescent signal when stimulated with the first stimulus signal.

[0018] According to one embodiment of the present invention, a comparison layer having a first comparison section is disposed on the second substrate side of the substrate, wherein the first comparison section has the first reference dye, the second reference dye, or the indicator dye.

[0019] According to one embodiment of the present invention, the comparison layer has a plurality of comparison segments, wherein each comparison segment has the first reference dye, the second reference dye, or the indicator dye.

[0020] According to one embodiment of the invention, the functional layer is circular and the functional segment is formed by radial sub-parts of the functional layer, or the functional layer is rectangular and the functional segment is formed by rectangular sub-parts of the functional layer.

[0021] According to one embodiment of the present invention, the functional sections of the functional layer are separated from each other by partition walls.

[0022] According to one embodiment of the invention, the inorganic first reference dye has materials from the following group:

[0023] Titanates, nitrides, gallates, sulfides, sulfates, aluminates, silicates, preferably HAN blue, HAN violet, Egyptian blue, ruby ​​red, aluminum borate, chromated yttrium aluminum borate, gadolinium aluminum borate, manganese(IV) doped magnesium titanate, manganese(IV) activated magnesium fluorogermanate, ruby, emerald green, and / or europium(III) activated yttrium oxide.

[0024] The organic second reference dye has materials from the group consisting of porphyrins and phthalocyanines with H, Mg, or Si as central ions, and the organic indicator dye has materials from the group consisting of porphyrins and phthalocyanines with Pd, Pt, Ir, Ru, La, Fe, Co, Ni, or Cu as central ions.

[0025] According to one embodiment of the present invention, the second reference dye has the same ligand as the indicator dye and a different central ion than the indicator dye.

[0026] The objective of the invention is further achieved by the photochemical oxygen sensor according to item 10.

[0027] The photochemical sensor according to the present invention comprises:

[0028] -A sensor body comprising a light source, a photodetector, and a control unit.

[0029] The control unit is connected to the light source and the photodetector, and is adapted to control the light source and evaluate the signal detected by the photodetector;

[0030] - A sensor head having a photochemical sensor element according to the present invention;

[0031] The sensor body and the sensor head are arranged such that the light source is adapted to emit at least one stimulus signal in such a way that the functional layer of the photochemical sensor element is irradiated by the stimulus signal.

[0032] The photodetector is adapted to detect the light emission signal emitted by the functional layer.

[0033] According to one embodiment of the present invention, the photodetector has a stimulation filter unit adapted to filter a first luminescence signal, a second luminescence signal, or a third luminescence signal emitted by the photochemical sensor element.

[0034] According to one embodiment of the present invention, the photochemical oxygen sensor further comprises an optical waveguide including at least two conductive fibers, wherein the light source is adapted to generate at least two independent stimulation signals.

[0035] The first conductor fiber is arranged such that the first stimulation signal is directed to the first functional segment.

[0036] Furthermore, the second conductor fiber is arranged such that the second stimulation signal is directed to the second functional segment.

[0037] According to one embodiment of the present invention, the optical waveguide has a third conductor fiber, wherein a second comparison section is disposed at one end of the third conductor fiber, or wherein the second comparison section is disposed in the optical waveguide or at the interface of the optical waveguide.

[0038] According to one embodiment of the present invention, the photochemical oxygen sensor further comprises a Y-shaped optical waveguide including at least two conductive fibers.

[0039] The two conductor fibers each have a first end, a second end, and a third end, and the light source is connected to the first end, the photochemical sensor element is connected to the second end of the first conductor fiber, and the photodetector is connected to the third end.

[0040] The second comparison section is arranged on the second end of the second conductor fiber.

[0041] The second comparison section includes the first reference dye, the second reference dye, or the indicator dye.

[0042] The object of the invention is also achieved by a method for measuring the oxygen content of a measurement medium using a photochemical oxygen sensor, as described in claim 15.

[0043] The method according to the present invention includes at least the following steps:

[0044] -Provides a photochemical oxygen sensor according to the present invention.

[0045] - By controlling the light source through the control unit, a first stimulation signal is emitted onto the functional layer of the photochemical sensor element to stimulate the second reference dye and indicator dye.

[0046] - The second and third emission signals are detected by a photodetector.

[0047] -The control unit compares the second luminescent signal emitted by the second reference dye with the third luminescent signal emitted by the indicator dye.

[0048] - Determine the signal difference or signal ratio between the second luminous signal and the third luminous signal.

[0049] - The oxygen content of the measurement medium is determined based on the second luminescent signal and the determined signal difference or signal ratio.

[0050] According to one embodiment of the present invention, the first functional segment further comprises a first reference dye, wherein the first reference dye comprises an inorganic material and is insensitive to oxygen, and is adapted to emit a first luminescent signal when stimulated with the first stimulus signal.

[0051] The step of controlling the light source by the control unit is performed in such a manner that a first stimulus signal is emitted onto the photochemical sensor element to stimulate the first reference dye.

[0052] The detection step includes detecting a first emission signal using the photodetector.

[0053] The comparison step further includes comparing the first light-emitting signal with the second light-emitting signal via the control unit.

[0054] The step of determining the signal difference or signal ratio further includes determining a second signal difference or signal ratio between the first emitted signal and the second emitted signal.

[0055] The step of determining the oxygen content of the measurement medium is further based on the first luminescent signal and the determined second signal difference.

[0056] According to one embodiment of the present invention, if the signal difference or the signal ratio exceeds or falls below a predetermined limit value, the control unit outputs a warning message.

[0057] According to one embodiment of the present invention, the photochemical oxygen sensor further comprises an optical waveguide including at least two conductive fibers, and the light source is adapted to generate at least two independent stimulation signals.

[0058] The first conductor fiber is arranged such that the first stimulation signal is directed to the first functional segment of the functional layer.

[0059] Furthermore, the second conductor fiber is arranged such that the second stimulation signal is directed to the second functional segment of the functional layer.

[0060] The step of controlling the light source by the control unit is performed in such a way that the first stimulus signal and the second stimulus signal are emitted in a time-shifted or simultaneous manner. Attached Figure Description

[0061] The invention will be explained in more detail with reference to the following accompanying drawings. The drawings are shown below:

[0062] - Figure 1 : A schematic diagram of the photochemical sensor element according to the present invention;

[0063] - Figure 2 : Figure 1 A schematic diagram of an alternative embodiment of the photochemical sensor element shown;

[0064] - Figure 3 : Figure 1 A schematic diagram of another alternative photochemical sensor element shown;

[0065] - Figure 4 : Figure 1 A schematic diagram of another alternative photochemical sensor element shown;

[0066] - Figure 5 : A schematic diagram of the photochemical oxygen sensor according to the present invention;

[0067] - Figure 6 : Figure 5 A schematic diagram of an alternative embodiment of the photochemical oxygen sensor shown;

[0068] - Figure 7 : Figure 5 A schematic diagram of another alternative embodiment of the photochemical oxygen sensor shown;

[0069] - Figure 8 : Figure 5 A schematic diagram of another embodiment of the photochemical oxygen sensor shown. Detailed Implementation

[0070] Figure 1An exemplary embodiment of a photochemical sensor element 10 for a photochemical oxygen sensor 1 is schematically illustrated. The photochemical sensor element 10 is intended for use in the photochemical oxygen sensor 1 to determine the oxygen content of a measurement medium in contact with the photochemical oxygen sensor 1. The photochemical oxygen sensor 1 is described in detail below in terms of its general structure, i.e., for the photochemical sensor element 10.

[0071] If luminescence or luminescent signal is mentioned below, it means fluorescence or fluorescent signal, and / or phosphorescence or phosphorescent signal.

[0072] The photochemical sensor element 10 includes a substrate layer 20 having a first substrate side 21 and a second substrate side 22. The first substrate side 21 is the side of the substrate layer 20 facing the measurement medium. A functional layer 30 is disposed on the first substrate side 21 (see [link]). Figure 1-7 The functional layer 30 faces the measurement medium and is configured to contact the measurement medium, at least in ion contact. Depending on the embodiment, the comparison layer 60 having at least one first comparison segment 61 may be disposed on the second substrate side 22 (see...). Figure 3-5 (Implementation method). The comparison layer 60 does not face the measurement medium and is designed not to contact the measurement medium. Depending on the implementation, a barrier layer 40 may be additionally arranged on the functional layer 30 such that the functional layer 30 is separated from the measurement medium by the barrier layer 40 (see Implementation Method). Figure 7 Here, "separation" means that barrier layer 40 prevents any ions from migrating to functional layer 30. For example, barrier layer 40 contains silicone or a fluoropolymer.

[0073] exist Figure 1-5 and Figure 7 In the illustrated embodiment, the photochemical sensor element 10 has a layered structure. However, the photochemical sensor element 10 can also be arranged in a ring around the axis X, as shown below. Figure 6 As shown in the embodiment.

[0074] like Figure 1-7 As shown, functional layer 30 is preferably subdivided into different functional segments 31-34. Functional segments 31-34 are separated from each other. This separation can be achieved through spatial distance A, for example, as shown in the diagram. Figure 1 As shown, or achieved through partition wall 35, for example, Figure 2 As shown. The distance A is, for example, between 0.1 μm and 1000 μm. The thickness of the partition wall 35 is, for example, between 0.1 μm and 1000 μm. The spacing or separation of the sections prevents the diffusion of dyes present in the sections.

[0075] exist Figure 1 In the illustrated embodiment, the first functional section 31 has a second reference dye RF2. The second functional section 32 has an indicator dye IF. Figure 2 In the embodiment shown, the first functional section 31 also has a first reference dye RF1.

[0076] like Figure 3-5 As shown, the first comparison segment 61 of the comparison layer 60 has an indicator dye IF, a first reference dye RF1, or a second reference dye RF2. Of course, the comparison layer 60 may also have more than one comparison segment. The comparison segments of the comparison layer 60 and the functional segments of the functional layer 30 are preferably arranged on the first substrate side 21 or the second substrate side 22 in such a way that each comparison segment and each functional segment can be stimulated by the first stimulation signal S1. This is achieved, for example, by ensuring that the comparison segments of the comparison layer 60 are not positioned relative to the functional segments of the functional layer 30 relative to the substrate layer 20 that separates the comparison segments and the functional segments (see [link to documentation]). Figure 3-5 In other words, the comparison segment on the first substrate side 21 and the functional segment on the second substrate side 22 should be avoided from being stimulated by the first stimulus signal in such a way that the light emission signals emitted by the comparison segment and the functional segment overlap.

[0077] Figure 7 Another embodiment is shown in which the second comparison section 70 is disposed on the conductor fiber of the optical waveguide 5 of the photochemical oxygen sensor 1. For example, the second comparison section 70 is arranged in a droplet shape at one end of the optical waveguide. Indicator dye IF and / or first reference dye RF1 and / or second reference dye RF2 are present in the second comparison section 70. The second comparison element 70 may also be disposed in the sensor head to be separated from the measurement medium. The second comparison section 70 is preferably located at the end of the optical path, for example at the end of a glass fiber or a bundle of glass fibers. For example, the second comparison section 70 is applied to the end of the conductor fiber. The second comparison section 70 may be an optically transparent layer disposed in the optical waveguide 5 and emitting constant phosphorescence upon excitation. The second comparison section 70 may also be disposed in front of or within the optical waveguide 5. In this case, the second comparison section 70 is transparent, allowing the emission signal to travel from the photochemical sensor element 10 through the second comparison section 5 to the photodetector 6.

[0078] Below is a table of various possible exemplary embodiments having the photochemical sensor element 10 or the photochemical oxygen sensor 1:

[0079]

[0080]

[0081] Wherein “S.1-V” to “S.6-V” (sections 1-6, front) characterize the functional sections of functional layer 30; “S.1-R” to “S.6-R” (sections 1-6, back) characterize the comparison sections of comparison layer 60; and “S.1-L” to “S.6-L” (sections 1-6, conductor fiber) characterize the second comparison section 70 on the conductor fiber of optical waveguide 5. The terms “IF”, “RF1”, and “RF2” correspond to the abbreviations of the dyes used in this document. “IF*” indicates that the dye is encapsulated, and therefore this is not affected by oxygen present in the medium. “dPHI” indicates a measurement method based on the decay time of one or more emission signals, and “rat.V.” indicates a measurement method based on ratio measurement, i.e., comparison of emission signals. “Detect drift” refers to the purpose of detecting drift caused by singlet oxygen or by photobleaching with the aid of emission signal evaluation in these embodiments. "Separation of effects" refers to the following objective: to detect different effects on the photochemical sensor element 10, particularly chemical effects, oxygen effects, singlet oxygen effects, and photobleaching effects, by evaluating the emission signals of these variant implementations, in order to estimate, for example, the lifetime of the photochemical sensor element 10. For readability, the tables have been separated.

[0082] The first reference dye RF1 is adapted to emit a first luminescent signal L1 when stimulated by a first stimulus signal S1. The first stimulus signal S1 preferably has a wavelength range of 400 nm to 600 nm or 500 nm to 600 nm. The first luminescent signal L1 preferably has a wavelength range of 600 nm to 1100 nm. The first luminescent signal L1 is a phosphorescent signal.

[0083] The first reference dye RF1 comprises inorganic materials. Examples of materials used in the first reference dye RF1 are described below.

[0084] The first reference dye RF1 is insensitive to oxygen. This means that the first luminescence signal L1 emitted by the first reference dye RF1 is independent of the oxygen content of the measurement medium. Therefore, the aging of the first reference dye RF1 caused by singlet oxygen is negligible. The first reference dye RF1 also exhibits resistance to photobleaching. Therefore, the aging of the first reference dye RF1 caused by photobleaching is negligible.

[0085] The second reference dye RF2 is adapted to emit a second luminescent signal L2 when stimulated by the first stimulus signal S1. The second luminescent signal L2 has a wavelength range of 400 nm to 1100 nm. Preferably, the second luminescent signal L2 has a wavelength range of 600 nm to 1100 nm. The second luminescent signal L2 is a fluorescent signal.

[0086] The second reference dye RF2 comprises an organic material and has the same ligands as the indicator dye IF. However, the second reference dye RF2 has a different central ion than the indicator dye IF (Pd, Pt, Ir, ...). For example, the second reference dye RF2 has a central ion (H, Si, Mg). Examples of materials used for the second reference dye RF2 are described below.

[0087] The second reference dye RF2 is insensitive to oxygen and is fluorescent. This means that the second emission signal L2 emitted by the second reference dye RF2 is independent of the oxygen content of the measurement medium. Therefore, the aging of the second reference dye RF2 caused by singlet oxygen is negligible.

[0088] However, due to photobleaching, the second reference dye RF2 is not entirely immune to aging. Photobleaching in the second reference dye RF2 causes a change in the second emission signal L2, i.e., a change in the measured value, which is also known as "drift".

[0089] The phosphorescent indicator dye IF is adapted to emit a third luminescent signal L3 upon stimulation with a first stimulus signal S1. The third luminescent signal L3 is preferably in the wavelength range of 400 nm to 1100 nm. The third luminescent signal L3 preferably has a wavelength range of 600 nm to 1100 nm. The third luminescent signal L3 is a phosphorescent signal.

[0090] Indicator dyes IF contain organic materials. Examples of materials used in indicator dyes IF are further described below.

[0091] The indicator dye IF is sensitive to oxygen. This means that the third luminescence signal L3 depends on the oxygen content of the measurement medium. Therefore, the intensity and / or decay time of the third luminescence signal L3 depend on the oxygen content of the measurement medium. Consequently, there is aging of the indicator dye IF caused by singlet oxygen. The aging of the indicator dye IF leads to changes in the third luminescence signal L3, resulting in continuous changes in the measured value, also known as "drift".

[0092] Due to photobleaching, the indicator dye IF cannot be protected from aging. Photobleaching in the indicator dye IF causes a change in the third luminescent signal L3, i.e., a change in the measured value, which is also known as "drift".

[0093] The substrate layer 20 is preferably transparent to the stimulation signal S1 and the light emission signals L1, L2, L3.

[0094] Figure 1 An embodiment of a photochemical sensor element 10 with a functional layer 30 is shown, the functional layer 30 having two functional segments 31, 32. Of course, the functional layer 30 can be subdivided into more than two functional segments.

[0095] By dividing the functional layer 30 into multiple functional segments, predetermined regions of the photochemical sensor element 10, namely the first functional segment 31 and the second functional segment 32, can be stimulated with different stimulation signals S1 and S2 emitted at different times, for example, with different wavelengths and / or at different times. Through the separate arrangement of the functional segments, the emission signals of dyes arranged in the functional segments can also be detected separately.

[0096] By dividing dyes RF1, RF2, and IF into separate functional segments 31, 32, and 33, or into different comparison segments 61, dyes RF1, RF2, and IF can be stimulated with different stimulation signals S1, S2, and S3, and / or the emission signals of dyes RF1, RF2, and IF arranged in the functional segments or comparison segments can be detected separately. For this purpose, for example, an optical waveguide with glass fiber bundles can be used to assign each functional segment or comparison segment to a fiber or glass fiber bundle so as to stimulate the dyes in the functional segments or comparison segments separately and detect the emission signals emitted from the dyes separately.

[0097] Of course, the functional layer 30 can be subdivided into more than three functional segments so that, for example, dye combinations of the first reference dye RF1 and / or the second reference dye RF2 and / or the indicator dye IF can be arranged for ratio measurement in other functional segments.

[0098] The functional layer 30 of the photochemical sensor element 10 is, for example, circular. If the circular functional layer 30 has functional segments 31, 32, 33, they are formed through radial sub-sections of the functional layer 30.

[0099] The functional layer 30 of the photochemical sensor element 10 can also have a rectangular shape. In this case, functional segments 31, 32, 33, and 34 are formed by rectangular sub-sections of the functional layer 30. It is naturally understood that other shapes of the functional layer 30 and the functional segments are also possible.

[0100] In an embodiment compatible with the above embodiments, the functional layer 30 has a matrix. In this case, the first inorganic reference dye RF1 and / or the organic indicator dye IF and / or the second organic reference dye RF2 are uniformly arranged in the matrix.

[0101] The uniform arrangement of dyes RF1, RF2, and IF in the matrix prevents crosstalk / energy transfer between excited and non-excited dyes.

[0102] By introducing materials with large surface areas and covalent bonds onto the surface of matrices such as sol-gels, fluoropolymers, or silicone resins, a best drift-stable photochemical sensor element 10 with optimal low load is produced.

[0103] In embodiments compatible with the above embodiments, the photochemical sensor element 10 further includes a barrier layer 40 (see [link to embodiment]). Figure 7 A barrier layer 40 is disposed on the side of the functional layer 30 opposite to the substrate layer 20. The barrier layer 40 is adapted to retain certain analytes in the measurement medium. This means preventing ions from migrating into the functional layer 30. The barrier layer 40 is oxygen-permeable. The barrier layer 40 can also serve as a protective layer for the functional layer 30. The barrier layer 40 ensures that no ions reach the photochemical element 10. However, it cannot isolate gases. Therefore, the barrier layer 40 is a protective layer against corrosive media such as fuming nitric acid.

[0104] In embodiments compatible with the above embodiments, the photochemical sensor element 10 has at least one additional layer. This additional layer is disposed on the substrate layer 20 and / or the functional layer 30 and / or the barrier layer 40 (not shown). The additional layer is, for example, a protective layer, a darkening layer, a support layer, or another barrier layer.

[0105] Preferably, functional sections 31, 32, and 33 are in contact with the substrate layer 20 or another layer via their first side surfaces. Functional sections 31, 32, and 33 are preferably in contact with the barrier layer 40 or another layer or the measuring medium via their second side surfaces, opposite to the first side surfaces (see [link to documentation]). Figure 7 ).

[0106] In embodiments compatible with the above embodiments, the first reference dye RF1 has materials from the group consisting of: titanates, nitrides, gallates, sulfides, sulfates, aluminates, silicates, preferably HAN blue, HAN violet, Egyptian blue, ruby ​​red, aluminum borate, chromium yttrium aluminum borate, gadolinium aluminum borate, manganese (IV) (doped) activated magnesium titanate, manganese (IV) activated magnesium fluorogermanate, ruby, emerald green and / or europium (III) activated yttrium oxide.

[0107] In embodiments compatible with the above embodiments, the indicator dye IF has materials from the group consisting of: halogenated BODIPY (dipyrrole methylene boron difluoride) and aza-BODIPY derivatives, porphyrins, phthalocyanines, cyanine, diketopyrrolopyrrole (DPP), quinacridone (QD), azadioxane-trigoneneonium (ADOTA) and its derivatives or mixtures.

[0108] Two examples of indicator dyes are as follows:

[0109]

[0110] An example of the second reference dye RF2 is as follows:

[0111]

[0112] Figure 5-7An exemplary embodiment of the photochemical oxygen sensor 1 according to the present invention is shown.

[0113] The photochemical oxygen sensor 1 is described below.

[0114] The photochemical oxygen sensor 1 has a sensor body 2 and a sensor head 3. The sensor head 3 is preferably detachably fastened to the sensor body 2. The term "sensor head" is also equivalent to the term "sensor cap." The advantage of a detachable sensor head 3 is that if it needs to be replaced, it can be done without discarding the sensor body 2. Therefore, the photochemical oxygen sensor 1 is also suitable for applications requiring, for example, a disposable sensor head.

[0115] The sensor head 3 includes the photochemical sensor element 10 described above according to the present invention.

[0116] The sensor body 2 and sensor head 3 extend, for example, along the axis X. The photochemical sensor element 10 preferably extends laterally relative to the axis X (see...). Figure 5 ) or extending circumferentially relative to axis X (see Figure 6 If the photochemical sensor element 10 extends laterally relative to the axis X, then the layers of the photochemical sensor element 10 are traversed by the axis X. If the photochemical sensor element 10 extends circumferentially relative to the axis X, then, for example, the layers of the photochemical sensor element 10 are arranged concentrically around the axis X.

[0117] like Figure 5 and Figure 6 As shown in the example, the sensor body 2 includes a light source 4, a photodetector 6, and a control unit 7.

[0118] The light source 4 is adapted to emit at least one stimulation signal S1, S2, S3 in such a manner that the functional layer 30 is illuminated by the stimulation signal S1. The light source 4 is, for example, an LED or an LED array. For example, the stimulation signals are guided onto the functional layer 30 via an optical waveguide 5 (see [link to relevant documentation]). Figure 5-7 ).

[0119] The photodetector 6 is suitable for detecting the light emission signals L1, L2, and L3 emitted by the functional layer 30. The photodetector 6 is, for example, a spectrometer, a CCD camera, or other detector.

[0120] Control unit 7 is connected to light source 4 and photodetector 6. Control unit 7 is adapted to control light source 4 and evaluate the signal detected by photodetector 6. If the emission signals L1, L2, L3 have different wavelengths, control unit 7 is adapted, for example, to filter the emission signals L1, L2, L3 detected by photodetector 6.

[0121] exist Figure 5 and Figure 6In the illustrated embodiment, the photochemical oxygen sensor 1 further comprises a stimulation filter unit 8 and a detection filter unit 9. The stimulation filter unit 8 is adapted to filter the stimulation signals generated by the light source 4 in such a manner that a first stimulation signal S1, a second stimulation signal S2, and / or a third stimulation signal S3, each having a different wavelength, are generated. If the light source 4 is adapted to generate different stimulation signals with different wavelengths, the stimulation filter unit 8 is not absolutely necessary. The stimulation filter unit 8 can generate different stimulation signals simultaneously or sequentially.

[0122] The detection filter unit 9 is adapted to filter superimposed emission signals with different wavelengths. If the emission signals illuminate the photodetector 6 in a time-shifted manner, i.e., they do not overlap, then the detection filter unit 9 is not absolutely necessary. If the photodetector 6 can quantize the detected superimposed emission signals of different wavelengths according to the wavelength of the detected emission signal, then the detection filter unit 9 is also not absolutely necessary, for example, for a spectrometer.

[0123] exist Figure 5 and Figure 6 In the embodiment shown, the photodetector 6 has a detection filter unit 9, which is adapted to filter the first light emission signal L1 emitted by the first reference dye RF1, the second light emission signal L2 emitted by the second reference dye RF2, and the third light emission signal L3 emitted by the indicator dye IF.

[0124] exist Figure 7 In the illustrated embodiment, the optical waveguide 5 comprises four conductor fibers 51, 52, 53, and 54. This allows for the generation of four independent stimulation signals S1, S2, S3, and S4, for example, via an LED array. Individual conductor fibers can also be enclosed by diaphragms (so-called "masks"), so that a single light source transmits stimulation signals only within predetermined conductor fibers. The first conductor fiber 51 is arranged such that the first stimulation signal S1 is directed to the first functional segment 31; the second conductor fiber 52 is arranged such that the second stimulation signal S2 is directed to the second functional segment 32; the third conductor fiber 53 is arranged such that the third stimulation signal S3 is directed to the third functional segment 33; and the fourth conductor fiber 54 is arranged such that the fourth stimulation signal S4 is directed to the fourth functional segment 34.

[0125] Figure 7The optical waveguide 5 shown is, for example, a Y-shaped optical waveguide 5. This means that each conductor fiber 51, 52, 53, 54 has a junction. One branch of the junction extends to the light source 4 (shown as a dashed line), and the other branch of the junction extends to the photodetector 6. The common portion of the Y-shaped optical waveguide 5 extends to a dedicated functional section or a comparison section. Thus, for example, a first stimulation signal S1 can be guided to a fourth functional section 34 via the first conductor fiber 51, and a first emission signal L1 can be guided to the photodetector 6 via the first conductor fiber 51. The optical waveguide 5 has the same structure in all the other conductor fibers 52, 53, and 54.

[0126] like Figure 7 As can be seen, the photochemical sensor element 10 is circular, and the functional segments 31, 32, 33, and 34 are defined by the radial sub-sections of the functional layer 30. The functional layer 30 is coated on the first substrate side 21 of the substrate layer 20. A selector layer 40 is mounted on the functional layer 30 such that the selector layer 40 is adapted to contact the measurement medium.

[0127] Figure 6 An embodiment of the photochemical oxygen sensor 1 is shown, wherein the photochemical sensor element 10 extends radially relative to an axis X defined by the sensor body 2 and the sensor head 3. The photochemical sensor element 10 is arranged, for example, annularly within the sensor head 3. For example, the sensor head 3 is sleeve-shaped, and the photochemical sensor element 10 is disposed on the inner surface of the sensor head 3. In this embodiment, the optical waveguide 5 includes corresponding guide portions 56 to facilitate the conduction of the stimulation signal from the light source 4 to the functional layer 30, and the conduction of the emission signal from the functional layer 30 to the photodetector 6. The radial arrangement of the functional layer 30 has the advantage that sensor spot subunits, such as functional segments, can be manufactured more easily using conventional methods such as scraping and spraying. Crosstalk between emission signals generated by functional segments or comparison segments is prevented by the clear separation of the individual functional segments or comparison segments. Individual detection of different emission signals enables simplified processing of the corresponding emission signals. Here, simpler processing means that simpler formulas can be used to evaluate signal measurements. The simpler formulas result in less computation and less memory requirements (because fewer memory locations are needed for parameters, coefficients, modulation frequencies, etc.).

[0128] The method for measuring oxygen content using the aforementioned photochemical oxygen sensor 1 is discussed below.

[0129] In the first step, a photochemical oxygen sensor 1 is provided. This means that the photochemical oxygen sensor 1 is functional and in contact with the measurement medium.

[0130] Subsequently, the light source 4 is activated by the control unit 7, causing the light source 4 to emit a first stimulation signal S1 onto the functional layer 30. The first stimulation signal S1 preferably has a wavelength in the range of 200 nm to 700 nm, more preferably 400 nm to 700 nm.

[0131] The second reference dye RF2 and the indicator dye IF are stimulated by the first stimulus signal S1, i.e., they are excited and emit light signals. Therefore, the stimulation of dyes RF2 and IF occurs simultaneously. Figure 1 As illustrated in the example, the second reference dye RF2 emits a second luminescent signal L2, and the indicator dye IF emits a third luminescent signal L3. Preferably, the luminescent signals have different wavelengths.

[0132] Then, the second emission signal L2 and the third emission signal L3 are detected by the photodetector 6. The photodetector 6 is adapted, for example, to analyze the spectrum of the detected radiation, so that emission signals of different wavelengths can be detected and filtered by the control unit 7.

[0133] In the next step, the detected emission signals L2 and L3 are evaluated by the control unit 7. This step includes, for example, filtering various emission signals by the control unit 7 so that emission signals L2 and L3 exist independently. However, if, for example, an optical waveguide 5 with dedicated conductor fibers 51 and 52 is used to conduct the emission signals from the functional section or comparison section to the photodetector 6, filtering the emission signals is not absolutely necessary.

[0134] Control unit 7 analyzes the second light emission signal L2 and the third light emission signal L3. The analysis of the light emission signals includes, for example, comparing or subtracting the amplitude (or phase difference / decay time) or integral of the signals of the second light emission signal L2 and the third light emission signal L3.

[0135] In the following text, signal difference, measurement signal difference, or reference signal difference is understood to refer to the time signal difference, amplitude difference, or ratio difference of the individual emission signals. Whether it means time / amplitude / ratio difference depends on the measurement method used (see the table above).

[0136] Then, the signal difference between the second emission signal L2 emitted by the second reference dye RF2 and the third emission signal L3 emitted by the indicator dye is determined. This signal difference can also be referred to as the measurement signal difference. Since only the indicator dye emitting the third emission signal L3 is oxygen-dependent, this signal difference can be used to detect drift caused by aging, for example, by singlet oxygen generated by photo-oxidation. These method steps are particularly useful in cases where the first reference dye RF1 is absent, such as... Figure 1 The example provided.

[0137] In the presence of a first reference dye RF1 in the photochemical sensor element 10, for example... Figure 2 As shown, the reference dye RF1 is also stimulated together with the second reference dye RF2 and the indicator dye IF in the above-described stimulation step, causing the first reference dye RF1 to emit a first emission signal L1. In the aforementioned detection step, the photodetector 6 also detects the first emission signal L1 and filters it if necessary.

[0138] Next, if the first reference dye RF1 is present in the photochemical oxygen sensor 1, for example... Figure 2 As shown, a second signal difference is determined between the first emission signal L1 emitted by the first reference dye RF1 and the second emission signal L2 emitted by the second reference dye RF2. This second signal difference can also be called the reference signal difference. This second signal difference is independent of the oxygen content of the measurement medium. Therefore, the drift of the second reference dye RF2 caused by photobleaching can be detected and quantified by the difference between the first reference dye RF1 and the second reference dye RF2, since the first reference dye RF1 is not exposed to drift.

[0139] To detect photobleaching, the first luminescence signal L1 from the first reference dye RF1 can be compared with the third luminescence signal L3 from the indicator dye IF.

[0140] This inherently leads to the ability to compare the emission signal ratios to detect, for example, photobleaching. Thus, for example, comparing the third emission signal L3 with the superimposed signal from the first emission signal L1 and the third emission signal L3 can also provide information about the presence of photobleaching in the dye (i.e., the indicator dye or the second reference dye RF2).

[0141] When the photochemical sensor element 10 undergoes drift, for example due to aging, the measurement signal difference and the resulting oxygen content of the measurement medium become distorted, requiring drift compensation. This corrects the determined or output oxygen content. This drift compensation is possible using the determined measurement signal difference.

[0142] For example, if the photochemical sensor element 10 does not drift, the difference between the measured signal and the reference signal will be zero. In this case, since drift does not need to be considered, the output oxygen content is not corrected.

[0143] However, if there is drift in the photochemical sensor element 10, the measurement signal difference will not be zero if the drift is caused by singlet oxygen, and the reference signal difference will not be zero if the drift is caused by photobleaching. In this case, the output oxygen content must be corrected to take the corresponding drift into account.

[0144] Thus, drift of the indicator dye IF and / or the second reference dye RF2 was detected.

[0145] Through drift compensation, the photochemical oxygen sensor 1 can be used even when drift exists in the photochemical sensor element 10, and the reliable oxygen content of the measurement medium can be determined. Therefore, the photochemical oxygen sensor 1 can be used for a longer time, is more reliable, and can perform more accurate oxygen content measurement of the measurement medium than conventional sensors.

[0146] In one embodiment, the method further includes the step of the control unit 7 outputting a warning message when the signal difference or signal ratio exceeds or falls below a limit value. This informs the user that drift exists and has been compensated for. Depending on the strength of the drift, for example, if it exceeds a limit value, a request to replace the sensor head 3 may also be issued. For this purpose, for example, changes in the measured value are measured at time intervals at a defined temperature. The control unit 7 is adapted to store the measurement data and / or improve the measurement data based on the identified drift. By replacing the sensor head 3, the photochemical sensor element 10 can be replaced along with the aged functional layer 30.

[0147] In an alternative embodiment, the photodetector 6 has an integrated detection filter to filter the emission signals L1, L2, L3. In this case, the photodetector 6 preferably has multiple detection regions, such as different pixels or pixel regions. The detection filter is preferably arranged such that a particular detection filter is upstream of a particular detection region, so that each detection region is suitable for detecting different emission signals.

[0148] In an alternative embodiment, the photodetector 6 has a detection filter unit 9 preceding the photodetector 6 (see [link]). Figure 5 and Figure 6 The detection filter unit 9 makes it possible to separate different light emission signals.

[0149] In an alternative embodiment, the light source 4 emits at least three different stimulation signals, each with a different wavelength. The light source 4 emits the stimulation signals simultaneously or sequentially.

[0150] In an alternative embodiment, the light source 4 is configured as an array of multiple LEDs and emits time-shifted stimulus signals using different LEDs.

[0151] Depending on whether the light source 4 has multiple independently activatable LEDs, the control of the light source 4 can be adapted to emit one or more stimulus signals simultaneously or independently of each other.

[0152] Depending on whether the photodetector 6 has multiple detection areas, the detection of the light emission signal by the photodetector 6 can be adapted by the control of the detection filter unit 9 and the light source 4, so that the light emission signal can be processed individually.

[0153] In one embodiment, the photochemical sensor element 10 includes a functional layer 30 having a single functional segment.

[0154] Functional layer 30 is manufactured as follows:

[0155] Using methods known to those skilled in the art, such as spin coating, blade coating, stencil printing, screen printing, spraying, inkjet printing, microdot coating, etc., segmented coatings are applied to a carrier (e.g., borosilicate glass) or a flexible substrate (e.g., PET).

[0156] Example 1:

[0157] For this purpose, for example in spraying, a mask is used to cover the unsprayed sections of the photochemical sensor element, but the mask exposes specific sections so that they can be sprayed. In a first step, for example, only one encapsulated or unencapsulated indicator dye from the silicone precursor material and an alkane from hexane are sprayed onto the first section and crosslinked.

[0158] In the second step, the encapsulated or unencapsulated organic second reference dye RF2 is then sprayed onto the second segment, i.e., the functional segment or reference segment, together with the silicone precursor in hexane, and cured if necessary. (The first segment and possibly other non-sprayed segments, naturally except the second segment, are again covered by a mask here).

[0159] In the third step, the inorganic first reference dye RF1 in the silicone precursor in hexane is sprayed onto the third segment and cured. (Of course, here the third segment is then exposed and all other segments are covered by a mask.)

[0160] Example 2:

[0161] For this purpose, a mask is used during the coating process to cover the area, leaving only specific regions (i.e., segments) exposed. In a first step, for example, only one encapsulated or unencapsulated indicator dye from the silicone precursor material is coated onto the first segment and crosslinked. The mask covering the coated surface (i.e., the first segment) is then reapplied.

[0162] In the second step, the encapsulated or unencapsulated organic second reference dye RF2 and inorganic first reference dye RF1, together with the silicone resin precursor, are then applied to the second segment by scraping and cured.

[0163] In the third step, the black silicone precursor is scraped and cured onto the cured coating of the first and second sections.

[0164] Oxygen concentration was calculated using the extended Stern-Volmer equation:

[0165]

[0166]

[0167] in:

[0168] τ0 = decay time in nitrogen

[0169] τ = decay time in the oxygen-nitrogen mixture

[0170] I0 = Intensity of nitrogen (or other non-sensitive gas / gas mixture)

[0171] I = Intensity in the residual oxygen gas mixture

[0172] α = Distribution coefficient

[0173] K SV1 = Stern-Volmer constant of the first field

[0174] K SV2 = Stern-Volmer constant of the first field

[0175] pO2 = oxygen partial pressure

[0176] f = factor

[0177] D I (T,t) = the change in the intensity of analyte dependence as a function of T,t

[0178] I S = Background Intensity

[0179] D Ksv (T,t) = the change of KSV as a function of T,t

[0180] The aforementioned ratio measurement method is discussed below. In this method, the emission signals L1-L3 emitted by the dyes (first reference dye RF1, second reference dye RF2, and indicator dye IF) are compared with each other. Specifically, the amplitude of the emission signal and the time curve of the emission signal are compared with each other. Thus, the reference signal ratio is obtained. If the ratio is equal to 1, there is no drift. If the ratio is less than or greater than 1, drift exists.

[0181] The determined oxygen content is corrected based on the drift determined by the ratio measurement method.

[0182] Some mathematical equations for the ratio measurement method are shown below:

[0183] I s (T,t0)=I S (T,t)

[0184]

[0185]

[0186] in:

[0187] K sv (T)=kq(T)xα(T)xτ0(T)

[0188] kQ0 = Bimolecular quenching constant

[0189] α = Oxygen solubility coefficient (according to Henry)

[0190]

[0191]

[0192]

[0193] An example of a change in the ratio of intensity (amplitude).

[0194]

[0195]

[0196] Examples of changes in time measurements

[0197] D1, D2 = drift as a) reference material, b) reference material and time.

[0198] dt = time period.

[0199] As an alternative to the ratio measurement method, the so-called "dual lifetime reference" (DLR) can also be applied.

[0200] Drift correction can be performed on both a single parameter and an overall term. This depends on the dye choice. In some cases, coefficients dependent on temperature and salinity (see dual lifetime references, as illustrated in the publications cited above) can also be included in the correction. It does not necessarily need to be a linear function as shown in the formula. Alternatively, a polynomial function or e^(-π / ... x function.

[0201] The emission signals L1, L2, and L3 detected by the photodetector 6 can also be evaluated by assessing the phase angle shift between the stimulus signals S1, S2, and S3 and the detected emission signals L1, L2, and L3.

[0202] Figure 8An embodiment of the photochemical oxygen sensor 1 is shown, further comprising a Y-shaped optical waveguide 5 having at least two conductor fibers 51 and 52. The two conductor fibers 51 and 52 each have first ends 511 and 521, second ends 512 and 522, and third ends 513 and 523. A light source 4 is connected to the first ends 511 and 521. A photochemical sensor element 10 is connected to the second end 512 of the first conductor fiber 51, and a photodetector 6 is connected to the third ends 513 and 523. A second comparison section 70 is disposed on the second end 522 of the second conductor fiber 52. The second comparison section 70 has a first reference dye RF1, a second reference dye RF2, or an indicator dye IF.

[0203] List of labels

[0204] 1. Photochemical Oxygen Sensor

[0205] 2. Sensor body

[0206] 3. Sensor head

[0207] 4. Light source

[0208] 5. Optical waveguide

[0209] 6. Photodetector

[0210] 7 Control Unit

[0211] 8. Stimulation Filter

[0212] 9. Detection Filter

[0213] 10 Photochemical Sensor Elements

[0214] 20 Substrate layer

[0215] 21 First substrate side

[0216] 22 Second substrate side

[0217] 30 Functional Layer

[0218] 31 First Functional Section

[0219] 32 Second Functional Section

[0220] 33 Third Functional Section

[0221] 34. Fourth Functional Section

[0222] 35. Partition wall

[0223] 40 barrier layers

[0224] 51 First Conductor Fiber

[0225] 52 Second Conductor Fiber

[0226] 53 Third conductor fiber

[0227] 54 Fourth Conductor Fiber

[0228] 56. Airflow guide

[0229] 60 Comparison Layer

[0230] 61 First comparison section

[0231] 70 Second comparison section

[0232] S1 First Stimulation Signal

[0233] S2 Second Stimulus Signal

[0234] S3 Third Stimulus Signal

[0235] L1 First Light Signal

[0236] L2 Second Light Signal

[0237] L3 Third Light Signal

[0238] RF1 First Reference Dye

[0239] RF2 Second Reference Dye

[0240] IF indicator dye

[0241] X-axis

Claims

1. A photochemical sensor element (10) for a photochemical oxygen sensor (1), comprising: - Substrate layer (20) has a first substrate side (21) facing the measurement medium and a second substrate side (22) opposite to the first substrate side (21); - A functional layer (30) is disposed on the first substrate side (21) and subdivided into at least two separate first functional segments (31) and second functional segments (32). The first functional section (31) has a second reference dye (RF2) and the second functional section (32) has an indicator dye (IF). The second reference dye (RF2) comprises organic materials and is insensitive to oxygen, and is adapted to emit a second luminescent signal (L2) upon stimulation with a first stimulus signal (S1). The indicator dye (IF) comprises an organic material and is sensitive to oxygen, and is adapted to emit a third luminescent signal (L3) upon stimulation with the first stimulus signal (S1). The substrate layer (20) is transparent to the first stimulus signal (S1), the first emission signal (L1), the second emission signal (L2), and the third emission signal (L3). The first functional segment (31) further comprises a first reference dye (RF1), wherein the first reference dye (RF1) comprises an inorganic material, is resistant to photobleaching, is insensitive to oxygen, and is adapted to emit a first luminescent signal (L1) when stimulated by the first stimulus signal (S1). The first reference dye (RF1) comprises materials from the group consisting of titanates, nitrides, gallates, sulfides, sulfates, aluminates, or silicates. The second reference dye (RF2) comprises materials from the following group: porphyrins or phthalocyanines with H, Mg, or Si as central ions, and The indicator dye (IF) has materials from the group consisting of porphyrins or phthalocyanines with Pd, Pt, Ir, Ru, La, Fe, Co, Ni, or Cu as the central ion. The aging of the second reference dye (RF2) is detected based on the first emission signal (L1) and the second emission signal (L2). The aging of the indicator dye (IF) is detected based on the first luminescence signal (L1) and the third luminescence signal (L3), or the second luminescence signal (L2) and the third luminescence signal (L3).

2. The photochemical sensor element (10) according to claim 1, wherein the first reference dye (RF1) has a material from the group consisting of: HAN blue, HAN violet, Egyptian blue, ruby ​​red, aluminum borate, chromium yttrium aluminum borate, gadolinium aluminum borate, manganese (IV) doped magnesium titanate, manganese (IV) activated magnesium fluorogermanate, ruby, emerald green and / or europium (III) activated yttrium oxide.

3. The photochemical sensor element (10) according to claim 1, wherein the functional layer (30) further comprises a third functional segment (33) having a first reference dye (RF1), wherein the first reference dye (RF1) comprises an inorganic material and is insensitive to oxygen, and is adapted to emit a first luminescent signal (L1) when stimulated with the first stimulus signal (S1).

4. The photochemical sensor element (10) according to any one of claims 1 to 3, wherein a comparison layer (60) having a first comparison section (61) is disposed on the second substrate side (22) of the substrate layer (20), wherein the first comparison section (61) has the first reference dye (RF1), the second reference dye (RF2) or the indicator dye (IF).

5. The photochemical sensor element (10) according to claim 4, wherein the comparison layer (60) has a plurality of comparison segments, wherein each comparison segment has the first reference dye (RF1), the second reference dye (RF2) or the indicator dye (IF).

6. The photochemical sensor element (10) according to any one of claims 1 to 3, wherein the functional layer (30) is circular and the first functional segment (31) and the second functional segment (32) are formed by radial sub-parts of the functional layer (30), or wherein the functional layer (30) is rectangular and the first functional segment (31) and the second functional segment (32) are formed by rectangular sub-parts of the functional layer (30).

7. The photochemical sensor element (10) according to any one of claims 1 to 3, wherein the first functional segment (31) and the second functional segment (32) of the functional layer (30) are separated from each other by a partition wall (35).

8. The photochemical sensor element (10) according to any one of claims 1 to 3, wherein the second reference dye (RF2) has the same ligand as the indicator dye (IF) and a different central ion than the indicator dye (IF).

9. A photochemical oxygen sensor (1), comprising: -A sensor body (2) comprising a light source (4), a photodetector (6), and a control unit (7), The control unit (7) is connected to the light source (4) and the photodetector (6), and is adapted to control the light source (4) and evaluate the signal detected by the photodetector (6); -A sensor head (3) having a photochemical sensor element (10) according to claim 1; The sensor body (2) and the sensor head (3) are arranged such that the light source (4) is adapted to emit at least one stimulation signal in such a way that the functional layer (30) of the photochemical sensor element (10) is irradiated by the stimulation signal. The photodetector (6) is adapted to detect the first light emission signal (L1), the second light emission signal (L2), and the third light emission signal (L3) emitted by the functional layer (30).

10. The photochemical oxygen sensor (1) according to claim 9, wherein the photodetector (6) has a stimulation filter unit (8) adapted to filter a first luminescence signal (L1), a second luminescence signal (L2) or a third luminescence signal (L3) emitted by the photochemical sensor element (10).

11. The photochemical oxygen sensor (1) according to claim 9 or 10, wherein the photochemical oxygen sensor (1) further comprises an optical waveguide (5) including at least two conductive fibers, wherein the light source (4) is adapted to generate at least two independent stimulation signals. The first conductor fiber (51) is arranged such that the first stimulation signal (S1) is directed to the first functional segment (31). Furthermore, the second conductor fiber (52) is arranged such that the second stimulation signal (S2) is directed onto the second functional segment (32).

12. The photochemical oxygen sensor (1) according to claim 11, wherein the optical waveguide (5) has a third conductor fiber (53) and a second comparison section (70) is disposed at one end of the third conductor fiber (53), or wherein the second comparison section (70) is disposed in the optical waveguide (5) or at the interface of the optical waveguide (5).

13. The photochemical oxygen sensor (1) according to claim 9, wherein the photochemical oxygen sensor (1) further comprises a Y-shaped optical waveguide including at least two conductive fibers. The two conductor fibers have a first end, a second end, and a third end, respectively, and the light source (4) is connected to the first end, the photochemical sensor element (10) is connected to the second end (512) of the first conductor fiber (51), and the photodetector (6) is connected to the third end. The second comparison section (70) is arranged on the second end (522) of the second conductor fiber (52). The second comparison section (70) has the first reference dye (RF1), the second reference dye (RF2), or the indicator dye (IF).

14. A method for measuring the oxygen content of a measuring medium, the method comprising at least the following steps: - Provides a photochemical oxygen sensor (1) according to claim 9, - The light source (4) is controlled by the control unit (7) so that the first stimulation signal (S1) is emitted onto the functional layer (30) of the photochemical sensor element (10) to stimulate the second reference dye (RF2) and the indicator dye (IF). - The second emission signal (L2) and the third emission signal (L3) are detected by photodetector (6). - The control unit (7) compares the second luminescent signal (L2) emitted by the second reference dye (RF2) with the third luminescent signal (L3) emitted by the indicator dye (IF). - Determine the signal difference or signal ratio between the second luminous signal (L2) and the third luminous signal (L3). - The oxygen content of the measurement medium is determined based on the second luminescent signal (L2) and the determined signal difference or signal ratio.

15. The method of claim 14, wherein the first functional segment (31) further comprises a first reference dye (RF1), wherein the first reference dye (RF1) comprises an inorganic material and is insensitive to oxygen, and is adapted to emit a first luminescent signal (L1) upon stimulation with the first stimulus signal (S1). The step of controlling the light source (4) by the control unit (7) is performed in such a manner that a first stimulation signal (S1) is emitted onto the photochemical sensor element (10) to stimulate the first reference dye (RF1). -The step of detecting the second emission signal (L2) and the third emission signal (L3) by the photodetector (6) includes detecting the first emission signal (L1) by the photodetector (6). The step of comparing the second luminescent signal (L2) emitted by the second reference dye (RF2) with the third luminescent signal (L3) emitted by the indicator dye (IF) via the control unit (7) further includes comparing the first luminescent signal (L1) with the second luminescent signal (L2) via the control unit (7). The step of determining the signal difference or signal ratio further includes determining a second signal difference or signal ratio between the first emitted signal (L1) and the second emitted signal (L2). -The step of determining the oxygen content of the measurement medium is further based on the first luminescent signal (L1) and the determined second signal difference.

16. The method according to claim 14 or 15, wherein if the signal difference or the signal ratio exceeds or falls below a predetermined limit value, the control unit (7) outputs a warning message.

17. The method according to claim 14 or 15, wherein the photochemical oxygen sensor (1) further comprises an optical waveguide (5) including at least two conductive fibers, and the light source (4) is adapted to generate at least two independent stimulation signals. The first conductor fiber (51) is arranged such that the first stimulation signal (S1) is directed to the first functional segment (31) of the functional layer (30). Furthermore, the second conductor fiber (52) is arranged such that the second stimulation signal (S2) is guided to the second functional segment (32) of the functional layer (30). The step of controlling the light source (4) by the control unit (7) is performed in such a manner that the first stimulation signal (S1) and the second stimulation signal (S2) are emitted in a time-shifted or simultaneous manner.

Images