Description

The invention relates to a sensor device for detecting a plurality of analytes, preferably in a mixture, comprising an array of sensor units that provides a specific output signal that consists of an entirety of individual optical signals of all sensor units and depends on an interaction with at least one analyte of the plurality of analytes and a sensor system to determine a presence and/or a concentration of a plurality of analytes comprising a sensor device.

Such a sensor device may be used to determine the molecular components in a gaseous or fluid mixture comprising one or more analytes of interest. Currently, this is commonly achieved with sensor devices that contain a sensing element that upon the interaction with one or several analytes changes its electronic properties e.g., its resistance. If the sensing element is connected to a suitable circuit, the interaction with the analyte leads to a change in the electronic properties which in turn leads to a change in an electrical signal and is thereby a measure of the presence and/or concentration of one or several analytes. In order to conduct measurements on mixtures composed of different, possibly unknown, components, a plurality of sensing elements is needed, each possessing different material properties, such that they show different responses to the different analytes in the mixture. An array of such sensing elements containing different materials can therefore provide the opportunity to distinguish mixtures comprising on or more analytes of interest and determine the concentration and composition of the individual analytes. This approach can be applied to examine gases and solutions containing different liquid components and solutes. However, technical difficulties arise in such sensor devices with an array of sensing elements as each sensing element requires a separate electrical connection to a readout circuit. The electrical wiring and connectivity of the plurality of sensing elements leads to a complexity that in practice restricts the number of sensing elements that can be used and that can be conveniently read out. As a consequence, this leads to a limited number of analytes that can be determined simultaneously and/or a reduction in the precision with which the components of the mixture can be identified.

As an alternative, arrays of sensing elements of different materials that directly change their optical properties e.g., their color, in conjunction with the exposure to an analyte has been suggested in the state of the art. However, the number of materials that show large and suitable differences in their optical response to different analytes is limited. In addition, the change in the optical properties is often not reversible i.e., it does not revert to the state prior to the interaction with the analyte. Therefore, such arrays are used as test strips, which are not amenable to continuous real-time measurements.

Object of the present invention is therefore to provide a sensor device that overcomes the above-mentioned disadvantages. In particular, the sensor device should allow a simultaneous detection of several analytes in a mixture of unknown components.

The problem is addressed by a sensor device for detecting a plurality of analytes, preferably in a mixture, comprising an array of sensor units that provides a specific output signal that consists of an entirety of individual optical signals of all sensor units and that depends on an interaction with at least one analyte of the plurality of analytes, wherein the interaction with the at least one analyte causes a reversible change in an electrical property of at least one sensor unit, wherein the change in the electrical property causes a reversible change in an optical property of the respective sensor unit and wherein the optical signal of the sensor unit depends on its optical property.

The advantage of the sensor device according to the present invention compared to the state of the art is that the reversible change in the electrical property of one of the sensor units leads to the corresponding reversible change in the respective sensor unit, wherein the optical signal of that respective sensor unit depends on the optical property and changes according to the change of the optical property. Consequently, the change in the electrical property of the sensor unit due to an analyte interaction causes a change in the optical signal of that sensor unit and thus changes the output signal of the array of sensor units. The output signal of the array of sensor units is thus specific to the analyte(s) interaction with the sensor units as each sensor unit has an individual optical signal depending on the analyte interaction. The conversion of the electrical change to the optical change in the sensor unit allows one to read out the optical signals of all the sensor units - that provide the specific output signal of the array of sensor units - in parallel.

Therefore, the sensor device can be conveniently read out without requiring separate electrical outputs. The present sensor device thereby does not need the electrical signal from each element to be fed a separate electrical output channel as the read-out of the interaction of the respective sensor unit with the analyte is optical. Advantageously, established devices that are based on sensing via electrical changes can be used, but without the need of a dedicated readout circuit that analyses all the electrical signals.

Moreover, the property of a sensor unit to interact with an analyte by changing an electrical property does not need to result in a change of an optical property. Rather, the present invention teaches how a change in the optical property of a sensor unit is directly affected by the change in the electrical property of that sensor unit. For example, a resistance change being the change in the electrical property of the sensor unit upon exposure to the analyte or a mixture of analytes, can be conveniently detected by readout of the optical signal of the sensor unit or the output signal of the array of sensor units, respectively. This simplifies the electrical wiring and architecture of the sensor device and permits the realization of arrays with a large number of sensor units.

The sensor units of the current invention are able to interact with at least one analyte, preferably in a mixture of different components. The analyte or the analytes are the components of the mixture that are of interest and should be or can be detected, respectively, by the interaction with at least one sensor unit. That means that an analyte can be detected by the sensor device if there is an interaction with at least one sensor unit that changes an electrical property of said sensor unit. As mentioned, preferably more than one sensor unit is able to interact with the same analyte so that the same analyte interacts with different sensor units to cause a change in the optical signal of that sensor units.

It is important that the change in the electrical property as well as the change in the optical property of the sensor units are both reversible. That means that the electrical property that is changed by the interaction with the at least one analyte returns to the initial state if there is no more interaction or the electrical property changes again to another state or value, respectively, if an interaction with another analyte occurs. The same applies mutatis mutandis to the optical property. It is understood that the change in the optical property of the sensor unit corresponds or is equivalent to the change of the electrical property

The output signal of the array of sensor units is composed of the optical signals of the sensor units. Every sensor unit provides a separate and independent optical signal that depends on the analyte interaction, wherein the entirety of optical signals of all sensor units constitutes the specific output signal of the array of sensor units of the sensor device, respectively. Accordingly, the output signal of the array of sensor units and also the sensor device is optical. The advantage is that all the optical signals of the sensor units can be read out or detected e.g., by an imaging device, in parallel. The interaction with an analyte or a mixture of analytes, preferably in a composition with further components, leads to a specific pattern of the output signal.

Preferably, the array of sensor units comprises 50 sensor units, more preferably, 100 sensor units, particularly preferably 500 sensor units and most preferably 1000 sensor units. The number of sensor units that form the array is not limited to these values since the big advantage of the current invention is that due to the optical read out of the output signal of the array of sensor units no complicated wiring or architecture is needed that otherwise becomes more complex as the number of sensor units is increased.

According to a preferred embodiment, all the sensor units are electrically connected to a common electrical power source. Preferably, the sensor units are connected to the power source by a common electrical connection of the array of sensor units or the sensor device, respectively. More preferably, the electrical power source is a current or voltage source. As described above, the electrical signal of each sensor unit does not have to be read out via an electrical signal separately since the optical signal of the sensor units can be read out and therefore the electrical wiring and architecture can be constructed a lot simpler. More preferably, the voltage level of all sensor units can be kept the same thus ideally only one voltage source must be controlled.

According to a further preferred embodiment, the electrical property is resistance, conductivity, capacity, charge, and/or polarization. Preferably, the optical property is emission intensity, absorption, extinction, refractive index and/or reflectivity. Advantageously, many different electrical and optical properties can be utilized. Preferably, the electrical property has an influence on the optical property or can influence the optical property so that a change in the electrical property leads to a respective change in the optical property. More preferably, the optical change influences the optical signal of the sensor unit so that the change in the optical property can be recognized by a change in the optical signal of the sensor unit.

According to a further preferred embodiment, each sensor unit comprises an electrical sensing element and an optical adapting element coupled to each other. Advantageously, each electrical sensing element is coupled to exactly one optical adapting element so that the number of electrical sensing elements and optical adapting elements of the sensor unit and the array of sensor units is the same. Therefore, one sensor unit is formed by exactly one electrical sensing element coupled to exactly one optical adapting element. Preferably, the electrical property is provided by the electrical sensing element and the optical property is provided by the optical adapting element. Preferably, the electrical sensing elements is able to interact with at least one analyte by changing its electrical property. Preferably, the optical adapting elements is able to change or to adapt its optical property corresponding to the change of the electrical property of the electrical sensing element. More preferably, the electrical sensing element and the optical adapting element are coupled so that the change in the electrical property of the electrical sensing element can be recognized by the optical adapting element. It is advantageous, to split the electrical and optical property in two separate elements that are coupled to each other since there is no need for a material that provides an electrical property that changes by the interaction with the analyte as well as provides a change in an optical property in response the electrical property change. Such materials as already stated above are very rare.

According to a further preferred embodiment, the electrical sensing element comprises a sensing material that is able to reversibly interact physically and/or chemically with at least one analyte of the plurality of analytes causing the change in the electrical property of the sensor unit. Preferably, the change in the electrical property depends on the composition and/or concentration of the interacting analyte. Also preferably, the material is selected from the group consisting of an inorganic material, an organic material, a polymer, a biomolecule, and any combinations thereof. Thereby, the change in the electrical property allows for the detection of the concentration and/or composition of the analyte as the change of the optical property corresponds to the electrical property change. Preferably, the physical and/or chemical interaction is adsorption, absorption, hydrogen bonding, dipole-dipole interaction, Van der Waals interaction, Lewis acid-Lewis base interaction, electrostatic interaction, coordination, complexation, covalent bonding, ionic bonding, metallic bonding, or any combinations thereof. It is understood that the types of interaction are not limited by the aforementioned examples. The interaction of the electrical sensing element or the sensing material, respectively, with the analyte has to induce a change in an electrical property of said electrical sensing element or sensing material, respectively.

Preferably, the electrical sensing element or the sensing material, respectively, is porous for analytes to diffuse in-and-out easily. More preferably, the electrical sensing element can be micro/nanoparticles, micro/nanowires or a porous thin film. These preferred embodiments are only examples for possible electrical sensing elements or the sensing materials, respectively. Particularly preferable, the electrical sensing element or the sensing material, respectively, comprises a surface that has nanostructuring, porosity, etc.

Preferably, the electrical sensing element or the sensing material, respectively, can be: a semiconducting metal oxide such as SnC>2, TiC>2, ZnO, CuO, CU2O, NiO, CoO, I^Ch, WO3, MoOs, CaO, La2Os, Nd20s, Y2O3, Ga2Os, Sb20s, Ce02, PbO, ZrO2, Fe2Os, Bi2Os, CeC>2, V2O5, VO2, Nb2C>5, CO3O4, RUC>2, or any combinations thereof; a perovskite-based oxide “ABO3” where A can be La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Ba or Y, and B can be Fe, Cr, Co, Ni or Ti; carbon nanotubes, graphene, reduced graphene oxides, or any combinations thereof; transition metal dichalcogenides such as M0S2, WS2, SnS2 and SnSe2, or any combinations thereof; transition metal carbides and nitrides “MAX”, where M can be Sc, Ti, Zr, Hf, V, Nb, Ta, Cr or Mo, A can be Al, Ga, In, TI, Si, Ge, Sn, Pb, P, As, Bi, S, or Te and X can be C or N; and/or polymers such as polypyrrole (PPy), polyaniline (PANI), polythiophene (PTh), poly(3,4- ethylendioxythiiophene) (PEDOT), polyphenylene, metal organic frameworks (MOFs).

More preferably, the electrical sensing elements or the sensing material, respectively, can be modified with metals such as Pt, Au, Ti, Pd, Ir, Ag, Ru, Ni, Fe, Al, Mo, Cr, Cu, W, Yb, Er, Gd, Sm, Pr, La, Tc, Sn, Ge, Si, Re, Cd, Nb, Y, Co, Mn, V, Sc, Sr, Mg, Tm, Dy, Eu, Nd, Ce, Bi, TI, Sb, In, Ga, Al, Ta, Zr, Zn, Ba, Ca, Cs, Li, or any combinations thereof, and/or with other oxides such as SnO2, TiO2, ZnO, CuO, CU2O, NiO, CoO, I n ₂ O3, WO3, MgO, CaO, La2Os, Nd20s, Y2O3, Ga2Os, Sb20s, AI2O3, SiO2, HfO2, CeO2, PbO, ZrO2, Fe2Os, Bi2Os, CeO2, V2O5, VO2, Nb20s, CO3O4, RUO2, or any combination thereof. Particularly preferable, the electrical sensing elements or the sensing material, respectively, can be functionalized by molecules such as metallophthalocyanine (MPc), metalloporphyrin (MP), polypyrrole (PPy), donor-TT-acceptor molecules (D-TT-A).

Also preferably, the electrical sensing elements or the sensing material, respectively, can compromise or be a biosensing material, such as a pore-protein, a G-protein-coupled receptor, an enzyme-linked receptor, an intracellular receptor, an antibody, a DNA nanostructure, an aptamer, a nerve cell or a cell.

According to a further preferred embodiment, each sensor unit comprises an electrical sensing element with a different sensing material. Advantageously, different sensing materials provide different interactions with different analytes causing different changes in one or more different electrical properties. Therefore, it is possible to detect a plurality of different analytes. Also, a more specific output signal can be provided if different interactions with different sensor units, electrical sensing elements or sensing materials, respectively, with the same analyte can occur since the output signal is composed of the entirety of individual optical signals of all sensor units so that a certain analyte causes a specific pattern in the output signal. Preferably, the sensing material is applied by physical vapor deposition, chemical vapor deposition, sintering, dip coating, spin coating, pyrolysis, spray application, dispensing, and/or chemical synthesis. The chemical synthesis could be for example hydrothermal synthesis, hydrolysis, sol-gel, co-precipitation. Preferably, the individual electrical sensing elements can be created by etching. Preferably, the sensing material is applied as a sensing layer. Preferably, a gradient of a sensing material with a varying composition can be applied i.e. , the sensing material composition or the sensing material itself changes gradually across the sensor units. More preferably, the sensing material or the sensing layer can have a catalyst applied onto the surface, e.g. by physical vapour deposition, chemical vapour deposition, dip coating, spin coating, spray application, and/or dispensing. Preferably, the sensing material or the sensing layer, respectively, can form a composite with a catalyst material. A ration of the sensing material or the sensing layer, respectively, and the catalyst material could be 0<x<50 (wt.%, at.%, or vol.%) where x is the catalyst material. Particularly preferable, the surface of sensing material or the sensing layer, respectively, can be engineered or functionalized with different specific molecules that exhibit different analyte interactions, e.g. by wet chemical treatment, covalent bonding, ion beam irradiation, polymer coating, physical vapor deposition, chemical vapor deposition, and/or vapor deposition polymerization. According to a further preferred embodiment, the optical adapting element is able to undergo an optical adaptation caused by the change in the electrical property due to the interaction with at least one analyte of the coupled electrical sensing element. Preferably, the optical adaptation of the optical adapting element causes the change in the optical property of the sensor unit. Advantageously, the optical adaptation of the optical adapting element is the change in the optical property of the sensor unit. More preferably, the optical adapting element is selected from the group consisting of a light emitting diode, an organic light emitting diode, a light emitting electrochemical cell, a laser, an electroluminescent device, a liquid crystal display, and an electrochromic material. Advantageously, the light emitting diode is 11 l-V semiconductor-based, ll-VI semiconductor-based, perovskite-based, and/or Quantum dot-based. The lll-V semiconductor-based or ll-VI semiconductor-based light emitting diode can be GaN-, GaAs-, or GaP- based and could preferably also include added Al. Preferably, the optical adaption of the optical adapting element directly or indirectly corresponds to the optical property or the change in the optical property of the sensor unit, respectively. Particularly preferable, the optical adaption of the optical adapting element can be an adaption or change of emission intensity, emission wavelength, luminescence, absorption, extinction, refractive index, reflectivity scattering, turbidity, transmittance and/or color. Advantageously, the optical adapting elements of all sensor units are similar e.g., all optical adapting elements are light emitting diodes, or all the optical adapting elements can change their reflectivity, as the read out is easier as the optical signal of the sensor units is then also similar.

According to a further preferred embodiment, the change in the electrical property is transmitted between the electrical sensing element and the coupled optical adapting element by means of an electric current, a field effect, a temperature effect, a tunneling, and/or a magnetic field effect. By this arrangement, the change in the electrical property can be communicated or transferred from the electrical sensing element to the optical adapting element so that an optical adaption of the optical adapting element can take place leading to the change in the optical property. Advantageously, the change in the electrical property is transmitted between the electrical sensing element and the coupled optical adapting element directly or indirectly. Preferably, a direct transmission is a transmission of electric current, wherein the change in the electrical property is a change in the current transmitted from the electrical sensing element to the optical adapting element. That means by a direct transmission the change in the electrical property is directly transmitted from the electrical sensing element to the optical adapting element. Advantageously, for a direct transmission of the change in the electrical property the electrical sensing element and the optical adapting element are conductively coupled so that e.g., electric current can be transmitted. More preferably, an indirect transmission takes place, when the change in the electrical property of the electrical sensing element is not directly transmitted to the optical adapting element. For example, by changing the electrical property a temperature of the electrical sensing element could be increased and that temperature increase could be transmitted to the optical adapting element which in turn undergoes an optical adaption changing the optical property. That would further mean that the electrical sensing element and the optical adapting element in that example are thermally coupled.

In the sense of the invention electrically coupled corresponds to conductively coupled. Moreover, an electrode corresponds to a conductor. However, in the sense of this invention any form of influence by the electrical sensing element that leads to a reversible change in the optical adapting element shall be considered, i.e. direct and indirect coupling. Someone skilled in the art may also combine a number of coupling mechanisms.

Preferably, the electrical sensing element and the optical adapting element are electrically connected by a conductor. The conductor can be made of Pt, Au, Ti, Pd, Ir, Ag, Ru, Ni, Fe, Co, STS, Al, Mo, Cr, Cu, W, ITO (Sn doped I^Os), FTO (F doped SnO2), graphene, carbon nanotube, a conducting polymer, or any combinations thereof.

According to a further preferred embodiment, the electrical sensing elements of all sensor units are arranged on a first electrically insulating substrate and the optical adapting elements of all sensor units are arranged on a second electrically insulating substrate. Preferably, each electrical sensing element is electrically connected to exactly one optical adapting element. Also preferably, electrical sensing elements and the optical adapting elements are electrically connected by conducting pins connecting respective pad electrodes of the electrical sensing elements and the optical adapting elements. More preferably, the first and the second electrically insulating substrate are spaced from each other and extend in parallel. This arrangement provides a simple wiring and device architecture. Preferably, the first and second substrate or the electrical sensing elements and the optical adapting elements, respectively, extend in the same plane, wherein the electrical sensing elements and the optical adapting elements are each arranged adjacently in that plane on the respective substrate. This arrangement leads to a large enough surface of the electrical sensing elements for interaction with analytes as well as a large enough surface of the optical adapting elements to be read out optically.

According to a further preferred embodiment, the electrical sensing element is arranged directly on the coupled optical adapting element. Preferably, the optical adapting elements of all sensor units are arranged on a common electrically insulating substrate. Advantageously, the optical adapting element is a patterned LED-structured wafer. This arrangement allows for a space saving sensor device. Moreover, the electrical sensing element or the sensing material, respectively, can be applied directly on the optical adapting element e.g., in form of a sensing layer, so that no complex wiring, or connection is necessary. More preferably, the electrical sensing element is electrically connected to the coupled optical adapting element, where the electrical sensing element is directly arranged on the electrode of the optical adapting element.

The object of the invention is also addressed by a sensor system to determine a presence and/or a concentration of a plurality of analytes comprising a sensor device according to one of the previous embodiments and an imaging device, wherein the imaging device detects the output signal of an array of sensor units of the sensor device.

Preferably, the imaging device is arranged in relation to the sensor device to be able to read out the output signal of the array of sensor units.

Advantageously, the imaging device is able to read out the output signal of the array of sensor devices, wherein the output signal is composed of the individual optical signals of all sensor units. As described above, every sensor unit can provide an individual optical signal that depends on its optical property or the optical adapting element’s optical adaption, respectively, influenced by the interaction of the analyte with the electrical sensing element and its corresponding electrical property change. Accordingly, the imaging device is able to read out all optical signals in parallel.

According to a preferred embodiment, the imaging device is selected from the group consisting of a human eye, a camera with photographic film, a CCD camera, a CMOS camera, a multichannel plate, and a diode array. It is understood that the imaging device should not be limited to the preferred examples. Imaging devices of that kind are well-known in the art and easy to handle so that it is beneficial to read out the optical signal instead of an electrical signal.

According to a further preferred embodiment, the sensor system comprises an evaluation unit, which is able to process the output signal of the array of sensor units detected by the imaging device to determine the presence and/or the concentration of the plurality of analytes interacting with the array of sensor units. Preferably, the evaluation unit uses computational analysis to process the output signal of the array of sensor units detected by the imaging device. More preferably, the evaluation unit uses machine learning algorithms for pattern recognition. As mentioned above, the output signal of the array of sensor units is composed of the optical signals of all sensor units, wherein each sensor unit has an individual optical signal depending on its electrical sensing element or sensing material, respectively, so that the specific output signal has a specific pattern. Preferably, the evaluation unit is signalling connected with the imaging device so that the evaluation unit is able to receive the data of the imaging device.

Advantageously, the specific output signal of the sensor device or the array of sensor units, respectively, is detected with the imaging device during interaction with a known analyte or known mixture of analytes by means of composition and/or concentration. That detected output signal according to the known analyte or known mixture of analytes is saved, preferably for later comparison with an output signal of unknown composition. Preferably, these saved output signals can be used to train and enhance the determination of the computational analysis.

The object of the invention is also addressed by a use of a sensor system according to one of the previous embodiments to determine a presence and/or a concentration of a plurality of analytes.

The object of the invention is also addressed by a method for determining a presence and/or a concentration of a plurality of analytes, preferably in a mixture, using a sensor system according to one of the previous embodiments comprising the steps:

- interacting an array of sensor units with at least one analyte,

- detecting the output signal of the array of sensor units with an imaging device,

- processing the output signal of the array of sensor units detected by the imaging device to determine the presence and/or the concentration of the at least one analyte by an evaluation unit.

The method may comprise the same embodiments and advantages as described in conjunction with the above-described sensor device and/or sensor system.

Further advantages, aims and properties of the present invention will be described by way of the appended drawings and the following description.

In the drawings:

Fig. 1 shows the sensor device according to one embodiment; Fig. 2a shows the sensor device according to another embodiment;

Fig. 2b shows the sensor device according to Fig. 2a in detail;

Fig. 3 shows a cross-sectional view of the sensor device according to Fig. 2a;

Fig. 4 shows the sensor system according to one embodiment.

In figures 1 and 2a a sensor device (1) for detecting a plurality of analytes, preferably in a mixture, according to different embodiments is depicted. The sensor device (1) comprises an array (2) of sensor units (3) that provides a specific output signal that consists of an entirety of individual optical signals of all sensor units (3) and depends on an interaction with at least one analyte of the plurality of analytes, wherein the interaction with the at least one analyte causes a reversible change in an electrical property of at least one sensor unit (3), wherein the change in the electrical property causes a reversible change in an optical property of the respective sensor unit (3) and wherein the optical signal of the sensor (3) unit depends on its optical property.

The sensor device (1) or the array (2) or sensor units (3), respectively, according to the different embodiments shown in figures 1 and 2a has a common electrical connection (4a) that is connected to a common electrical power source (4b) (not shown). The common electrical connection of the sensor device (1) or the array (2) or sensor units (3), of the embodiment of figure 2a can be seen in figure 3 (more details below). The array (2) of sensor units (3) comprises a plurality of sensor units (3), wherein only one is marked with a reference sign.

In the embodiments of the sensor device (1) shown in figures 1 and 2a each sensor unit (3) comprises an electrical sensing element (5) and an optical adapting element (7) coupled to each other, wherein the electrical property is provided by the electrical sensing element (5) and the optical property is provided by the optical adapting element (7). Each electrical sensing element (5) is coupled to exactly one optical adapting element (7). In the depicted embodiments the electrical sensing elements (5) and the optical adapting elements (7) are electrically coupled, wherein the electrical property or the change in the electrical property is directly transmitted between the electrical sensing elements (5) and the coupled optical adapting elements (7) by means of a transmission of electric current. Only one of the electrical sensing elements (5) and the optical adapting elements (7) is marked with a reference sign. The electrical sensing elements (5) and the optical adapting elements (7) are square-shaped. But it is understood that said elements (5, 7) could also have any other form, like disc-shape, triangular-shape etc.

The electrical sensing element (5) comprises a sensing material (6) that is able to reversibly interact physically and/or chemically with at least one analyte of the plurality of analytes causing the change in the electrical property of the sensor unit (3). The change in the electrical property depends on the composition and/or concentration of the interacting analyte.

The optical adapting element (7) is able to undergo an optical adaptation caused by the change in the electrical property due to the interaction with at least one analyte of the coupled electrical sensing element (5). The optical adaptation of the optical adapting element (7) causes the change in the optical property of the sensor unit (3), wherein the optical adapting element (7) is a light emitting diode.

The differences of the embodiments of the sensor devices (1) shown in figures 1 and 2a are described in the following.

According to the embodiment of the sensor device (1) of figure 1 , the electrical sensing elements (5) of all sensor units (3) are arranged on a first electrically insulating substrate (8a) and the optical adapting elements (7) of all sensor units (3) are arranged on a second electrically insulating substrate (8b). Each electrical sensing element (5) is electrically connected to exactly one optical adapting element (7) by conducting pins (9). The conducting pins (9) connect pad electrodes (10) of the electrical sensing elements (5) and the optical adapting element (7) with each other. The conducting pins (9) connect or couple the electrical sensing elements (5) and the respective optical adapting elements (7) electrically. The first (8a) and the second electrically insulating substrate (8b) are spaced from each other forming an open space in between and extend essentially in a plane perpendicular to one another. The conducting pins (9) extend through the space between the first (8a) and the second substrate (8b). The electrical sensing elements (5) and the optical adapting elements (7) do not face each other but the optical adapting elements (7) point away from the first substrate (8a), whereas the electrical sensing elements (5) are pointing into the space between the substrates (8a, 8b). A part of the second electrically insulating substrate (8b) and the optical adapting elements (7) is cut out so that the first electrically insulating substrate (8a) with the electrical sensing elements (5) can be seen more conveniently.

According to the embodiment of the sensor device (1) of figure 2a, the electrical sensing elements (5) are arranged directly on the coupled optical adapting elements (7). The optical adapting elements (7) of all sensor units (3) are arranged on a common electrically insulating substrate (11). The detailed arrangement can be seen in figure 3 depicting a cross-sectional view.

The common substrate (11) extends essentially in one plane, wherein the optical adapting elements (7) are arranged adjacent to each other on one face of the common substrate (11). The electrical sensing elements (5) are arranged directly on a face of the optical adapting elements (7) opposite to the common substrate (11). The common substrate (11) is optically transparent enabling the readout of changes in optical properties through the substrate on the opposite side of the electrical sensing elements.

In figure 2b a detailed view of the top surface of the sensor device (1) according to the embodiment of figure 2a is shown. Thereby, only the electrical sensing elements (5) can be seen, the optical adapting elements (7) are arranged beneath.

All the electrical sensing elements (5) are in contact to a common electrode (12), which is connected to the common electrical connection (4a) that in turn is connected to the common electrical power source (4b), both of which are not shown. By the common electrode (12) all the sensor units (3) are supplied by the same electrical power source (4b) with the same electric voltage. The common electrode (12) contacts the electrical sensing elements (5) on a face opposite to the face contacting the optical adapting elements (7).

As shown in figure 2b, each sensor unit (3) comprises an electrical sensing element (5) with a different sensing material (6). The different sensing materials (6) are depicted exemplarily by different shapes (as can be seen from figure 2b: circles, squares, rectangles, stars, pentagons, ellipses and these shapes also in different sizes). The sensing material (6) can be applied by physical vapor deposition, chemical vapor deposition, sintering, dip coating, spin coating, pyrolysis, spray application, dispensing, and/or chemical synthesis. The individual electrical sensing elements (5) can be created by etching. Each sensing material (6) preferably shows a different interaction with the analyte(s) resulting in a different change in the electrical property and in turn of the optical property of the optical adapting element (7). Thereby, the sensitivity of the sensor device (1) is increased.

Figure 3 depicts a cross-sectional view of the embodiment of the sensor device (1) shown in figures 2a and 2b. The section is made perpendicular to the plane in which the sensor device

(I) extends.

In the cross-sectional view the arrangement of the different parts of the sensor device (1) can be seen. From the bottom up, on the common substrate (11) the optical adapting elements (7) are arranged forming a common ground electrode (13) in between. The common substrate

(I I) is transparent so that the change in the optical property or the optical adaptation, respectively, can be recognized from the bottom through the common substrate (11).

On top of the optical adapting elements (7) opposite to the common substrate (11) the electrical sensing elements (5) are arranged in direct contact. Again, on top of the electrical sensing elements (5) opposite to the optical adapting elements (7) the common electrode (12) extends supplying all the sensor units (3) with the same voltage.

In this specific embodiment of the sensor device (1) shown in figures 2a, 2b, and 3, the optical adapting elements (7) are light emitting diodes (LED), particularly a patterned LED-structured wafer with individual LED pixels, wherein one individual LED pixel corresponds to one optical adapting element (7). The n-doped layers of the individual LED pixels are connected with each other to form the common ground electrode (13). The electrical sensing elements (5) are directly applied on the p-doped layer of the LED pixels so that an electrical connection is formed. By this arrangement, a change in electrical current (electrical property) is directly transmitted from the electrical sensing element (5) to the optical adapting element (7) causing an optical adaption and in turn a change in the optical property of the respective sensor unit (3).

In figure 4 the sensor system (100) according to one embodiment of the present invention.

The sensor system (100) for determining a presence and/or a concentration of a plurality of analytes comprises the sensor device (1) according to one of the previous embodiments and an imaging device (14). The imaging device (14) is able to detect an output signal of the array (2) of sensor units (3) of the sensor device (1). The output signal of the array (2) of sensor units (3) is optical and consists of the individual optical signals of each of the sensor units (3). Furthermore, the imaging device (14) has a detection area (16), in which optical signals or optical output signals, respectively, can be recognized. The sensor device (1) or the array (2) of sensor units (3) is arranged so that the output signal can be detected completely i.e. , that all optical signals of all sensor units (3) can be detected or read out in parallel.

The sensor device (1) or the array (2) of sensor units (3), respectively, is electrically connected via the common electrical connection (4a) to the common electrical power source (4b) supplying the sensor device (1) and all sensor units (3) with a common voltage.

The imaging device (14) is selected from the group consisting of a human eye, a camera with photographic film, a CCD camera, a CMOS camera, a multichannel plate, and a diode array.

The imaging device (14) is signalling connected to an evaluation unit (15). The evaluation unit (15) is able to process the output signal of the array (2) of sensor (3) units detected by the imaging device (14) to determine the presence and/or the concentration of the plurality of analytes interacting with the array (2) of sensor units (3). The evaluation unit (15) preferably uses computational analysis to process the output signal of the array (2) of sensor units (3) detected by the imaging device ‘(14). This could be done with machine learning algorithms for pattern recognition.

All the features disclosed in the application documents are claimed as being essential to the invention if, individually or in combination, they are novel over the prior art.

List of reference numerals

1 sensor device

100 sensor system

2 array of sensor units

3 sensor unit

4a common electrical connection

4b common power source

5 electrical sensing element

6 sensing material

7 optical adapting element

8a first substrate

8b second substrate

9 conducting pin 10 pad electrode

11 common substrate

12 common electrode

13 common ground electrode 14 imaging device

15 evaluation unit

16 detection area