Optoelectronic device for detecting a gas

Abstract

An optoelectronic device for detecting a gas is specified. According to one embodiment, the optoelectronic device (1) for detecting a gas comprises a radiation-emitting element (4) configured for emitting an electromagnetic radiation, a measurement unit (5) comprising a measurement region (51) and a reference region (52), a detector unit (6) comprising at least a first photodetector region (61) and a second photodetector region (62), and a reflection prism (8), wherein the reflection prism (8) is arranged on the radiation-emitting element (4) and the detector unit (6), wherein the measurement region (51) is arranged in a first beam path of the electromagnetic radiation between the radiation-emitting element (4) and the first photodetector region (61), wherein the reference region (52) is arranged in a second beam path of the electromagnetic radiation between the radiation-emitting element (4) and the second photodetector region (62), and wherein the optoelectronic device (1) is surface mountable. In particular, the radiation-emitting element (4) comprises a micro-LED.

Description

[0001] Description

[0002] OPTOELECTRONIC DEVICE FOR DETECTING A GAS

[0003] An optoelectronic device for detecting a gas is speci fied .

[0004] It is an obj ect to provide a compact optoelectronic device for detecting a gas .

[0005] An optoelectronic device for detecting a gas is speci fied . In particular, the optoelectronic device is configured for detecting the presence of a gas by using electromagnetic radiation . For example , a change of an intensity, a wavelength, a frequency and / or a polari zation of the electromagnetic radiation is detectable in the presence of the gas . In particular, a level of the change depends on an amount of the gas present . For example , i f more gas is present , the change will be more pronounced . For instance , the optoelectronic device for detecting a gas is configured for detecting a gas in a concentration of between and including 0 . 01 % and 4 % . In particular, the optoelectronic device is a gas sensor . For example , the gas is hydrogen (H2) or ammonia (NH3) or a harmful gas such as SOXor NOX.

[0006] According to at least one embodiment , the optoelectronic device comprises a radiation-emitting element configured for emitting an electromagnetic radiation . In particular, the radiation-emitting element is a radiation-emitting diode such as a light-emitting diode ( LED) . Alternatively, the radiation-emitting element can be a surface emitting laser such as a vertical cavity surface emitting laser (VCSEL ) or an edge emitting laser . Here and in the following, the terms light and electromagnetic radiation are used interchangeable . In particular, the electromagnetic radiation comprises a wavelength or a wavelength range of the ultraviolet (UV) wavelength range , the visible (VIS ) wavelength range and / or the infrared ( IR) wavelength range . For example , the electromagnetic radiation is radiation in the infrared wavelength range . In particular, the electromagnetic radiation comprises a wavelength or a wavelength range between and including 1100 nm and 1500 nm, for example between and including 1200 nm and 1400 nm or between and including 1250 nm and 1350 nm, for instance between and including 1280 nm and 1300 nm . Alternatively, the electromagnetic radiation can comprise a wavelength or a wavelength range between and including 800 nm and 900 nm .

[0007] According to at least one embodiment , the optoelectronic device comprises a measurement unit comprising a measurement region and a reference region . In particular, the measurement unit is configured for detecting the gas . For example , the measurement region of the measurement unit is configured for interacting with the gas , for instance binding the gas to the measurement region . In particular, the reference region is configured for not interacting with the gas .

[0008] According to at least one embodiment , the optoelectronic device comprises a detector unit comprising at least a first photodetector region and a second photodetector region . In particular, each photodetector region is configured for detecting an electromagnetic radiation incident on the respective photodetector region . For example , each photodetector region is configured for detecting an intensity, a wavelength, a frequency, and / or a polari zation of the incident electromagnetic radiation . In particular, the first photodetector region and the second photodetector region are operable independently of one another . For example , the first photodetector region comprises or consists of a first photodiode and the second photodetector region comprises or consists of a second photodiode . Alternatively, the first photodetector region can be a first part of a two- part photodiode and the second photodetector region can be a second part of the two-part photodiode . The photodetector unit can comprise a plurality of photodetector regions . For example , the photodetector unit can comprise a plurality of first photodetector regions and a plurality of second photodetector regions .

[0009] According to at least one embodiment , the optoelectronic device comprises a reflection prism . In particular, a reflection prism comprises at least one , in particular two , side surfaces that are reflective for electromagnetic radiation and at least one side surface that is transmissive for electromagnetic radiation . It should be noted that the reflectivity of the side surface ( s ) of the reflection prism depends on the nature of the boundary surface of the reflection prism . A reflection prism surrounded by air comprises a total internal reflection at the reflective boundary surfaces . In the case that the boundary surface is formed with a material di f ferent than air, electromagnetic radiation can pass through the boundary surface and enter the material on the boundary surface .

[0010] For example , the reflection prism is a triangular reflection prism . A triangular reflection prism comprises two parallel triangular sides and three rectangular sides . For example , the triangular sides form a right-angled triangle , in particular an isosceles right-angled triangle . In other words , the reflection prism can be referred to as a right- angled reflection prism, in particular as an isosceles right- angled reflection prism . For example , the rectangular sides adj acent to the right angle are reflective for electromagnetic radiation . For instance , the rectangular side opposite the right angle is transmissive for electromagnetic radiation . In particular, the reflection prism is made of optical glass . For example , the reflection prism comprises a length of its largest side of between and including 1 mm and 5 mm, for instance 3 mm .

[0011] In particular, a base of the reflection prism is simply connected . Here , simply connected is meant in the mathematical sense . For example , the base of the reflection prism is a continuous surface without voids and / or cutouts . For instance , the reflection prism is free of cutouts , cavities and / or openings .

[0012] According to at least one embodiment , the reflection prism is arranged on the radiation-emitting element and the detector unit . In particular, the reflection prism is arranged on the radiation-emitting element and the first photodetector region and / or the second photodetector region . For example , the reflection prism is arranged in such a way that the rectangular side transmissive for electromagnetic radiation is facing the radiation-emitting element and the first photodetector region and / or the second photodetector region . The reflection prism can be mounted on supporting fixtures or on the radiation-emitting element and the detector unit .

[0013] According to at least one embodiment , the measurement region is arranged in a first beam path of the electromagnetic radiation between the radiation-emitting element and the first photodetector region . In particular, the first beam path is a path of at least a part of the electromagnetic radiation starting from the radiation-emitting element and ending at the first photodetector region . In other words , the first photodetector region is configured for detecting a measurement signal .

[0014] According to at least one embodiment , the reference region is arranged in a second beam path of the electromagnetic radiation between the radiation-emitting element and the second photodetector region . In particular, the second beam path is a path of at least a part of the electromagnetic radiation starting from the radiation-emitting element and ending at the second photodetector region . In other words , the second photodetector region is configured for detecting a reference signal . In particular, the first beam path and the second beam path are independent of one another . For example , the first beam path and the second beam path are separate beam paths . The first beam path and the second beam path can be parallel to one another . For instance , the first beam path and the second beam path do not overlap .

[0015] In particular, the first beam path and / or the second beam path essentially run exclusively within the reflection prism . In other words , an optical path between the radiationemitting element and the detector unit essentially runs exclusively within the reflection prism . Here and in the following essentially means in particular to an extent of at least 90% , for example at least 95% , for instance at least 98 % .

[0016] According to at least one embodiment , the optoelectronic device is surface mountable . A surface mountable optoelectronic device is , in particular, directly mountable onto the surface of a printed circuit board ( PCB ) . For example , the optoelectronic device is referred to as a surface-mount device ( SMD) . Here and in the following, mountable or mounted components or devices are attachable or attached to an underlying surface such as a substrate , a housing, or a printed circuit board . The components or devices can be attached by a connection mean such as a soldered contact or an adhesive layer . In particular, the optoelectronic device for detecting a gas is designed as a surface mountable package . For example , the optoelectronic device is a gas sensor designed as a surface mountable package .

[0017] According to at least one embodiment , the optoelectronic device comprises a radiation-emitting element configured for emitting an electromagnetic radiation, a measurement unit comprising a measurement region and a reference region, a detector unit comprising at least a first photodetector region and a second photodetector region, and a reflection prism, wherein the reflection prism is arranged on the radiation-emitting element and the detector unit , wherein the measurement region is arranged in a first beam path of the electromagnetic radiation between the radiation-emitting element and the first photodetector region, wherein the reference region is arranged in a second beam path of the electromagnetic radiation between the radiation-emitting element and the second photodetector region, and wherein the optoelectronic device is surface mountable .

[0018] It is an idea of the present application to provide a surface mountable optoelectronic device for detecting a gas comprising all components of a gas detecting system in a compact design . The optoelectronic device is simple and cost- ef ficient . The measurement unit having a measurement region and a reference region has an uncomplicated and thus insensitive design and, due to the reference region, allows a reference measurement . The reference measurement can be performed automatically without using valves or reference gases or reference chambers . This can advantageously increase the length of use and the li fetime of the optoelectronic device . Due to the reference measurement , the measurement for detecting the gas is independent of factors such as a color or a spectral composition of the radiation-emitting element which can change during the li fetime of the radiationemitting element , for example , due to deposition of dust on the radiation-emitting element . Thus , it is advantageous to base the measurement on a relative measurement result determined by comparing the measurement signal and the reference signal instead of only using the absolute value of the measurement signal . In other words , the optoelectronic device allows to detect a relative change in the measurement signal compared to the reference signal . The measurement result is thus independent of the absolute intensities detected by the photodetector regions . Further, the reference measurement suppresses disturbance variables and improves the signal-to-noise ratio . The signal-to-noise ratio is further improved by using a first photodetector region for providing the measurement signal and a second photodetector region for providing the reference signal . Furthermore , by using a simple optical prism arrangement , the first beam path and / or the second beam path can be directed simply and ef ficiently between the radiation-emitting element and the detector unit .

[0019] According to at least one embodiment , the optoelectronic device comprises a substrate . In particular, the substrate is configured for providing a support and / or mounting the components of the optoelectronic device such as the radiation-emitting element and the detector unit . For example , the substrate is a SMT-substrate . Here and in the following, SMT is the abbreviation for surface mount technology . In particular, a SMT-substrate only comprises solderable connection surfaces or solderable connection pins for connecting the SMT substrate to , for example , a printed circuit board . In other words , the SMT-substrate is free of wire bonds . A SMT-substrate can advantageously be provided cost-ef f iciently . An optoelectronic device comprising a SMT- substrate is advantageously easy to install , in particular easy to integrate into a control system such as a control system of a heating system .

[0020] According to at least one embodiment , electrical connection pads of the optoelectronic device are exclusively arranged on the side of the substrate facing away from the radiationemitting element , the measurement unit , the detector unit , and the reflection prism . In particular, all electrical connection pads of the optoelectronic device are arranged on one side of the substrate , wherein the components of the optoelectronic device such as the radiation-emitting element , the measurement unit , the detector unit , and the reflection prism are arranged on the opposite side of the substrate . A substrate having electrical connection pads exclusively facing away from the components of the optoelectronic device can advantageously be surface mounted simply and ef ficiently .

[0021] According to at least one embodiment , the gas is hydrogen . Hydrogen gas is used as a fossil- free energy carrier, for example as hydrogen fuel . Hydrogen gas is highly flammable and forms explosive mixtures with air . The explosive reactions may be triggered by spark, heat , or sunlight . Thus , for a safe introduction and distribution of hydrogen gas for private mobility and home technology such as heating or energy storage , cost-ef ficient hydrogen sensors are needed . A simple and cost-ef ficient optoelectronic device for detecting hydrogen in a compact design can advantageously be used for increasing the safety of such applications .

[0022] According to at least one embodiment , the optoelectronic device comprises a housing . The housing is configured for protecting the components of the optoelectronic device such as the radiation-emitting element , the measurement unit , the detector unit , and the reflection prism against damage , in particular, by providing a protective barrier against external influences such as a deposition of dust on sensitive surfaces of the components . In particular, the housing is impermeable to the electromagnetic radiation emitted by the radiation-emitting element . In this instance , the environment surrounding the optoelectronic device is protected against the electromagnetic radiation emitted by the radiationemitting element . Further, the optoelectronic device , in particular the detector unit , is protected against electromagnetic radiation from external radiation sources located outside the optoelectronic device . The housing can further be impermeable to electromagnetic radiation having a di f ferent wavelength or wavelength range than the electromagnetic radiation emitted by the radiation-emitting element . A housing, in particular a radiation-impermeable housing, can advantageously improve the signal-to-noise ratio and suppress disturbance variables .

[0023] According to at least one embodiment , the housing is formed by inj ection molding . An inj ection molded housing is stable and can advantageously be provided cost-ef f iciently . According to at least one embodiment , the substrate and the housing surround a volume , in particular completely . In particular, the volume is a three-dimensional space surrounded by side surfaces . The substrate can cover a side surface of the volume and the housing can cover the remaining side surfaces of the volume . For example , the volume is completely surrounded by the substrate and the housing in such a way that electromagnetic radiation, in particular at least electromagnetic radiation having the wavelength or the wavelength range emitted by the radiation-emitting element , from external light sources cannot enter the volume . Surfaces of the housing facing towards the volume can be referred to as inside surfaces of the housing .

[0024] According to at least one embodiment , the radiation-emitting element , the measurement unit , the detector unit , and the reflection prism are arranged in the volume . In particular, the radiation-emitting element , the measurement unit , and the detector unit are mounted on the substrate and / or on inside surfaces of the housing within the volume . Thus , a compact design of the optoelectronic device can advantageously be reali zed .

[0025] According to at least one embodiment , the housing comprises a gas inlet . In particular, the gas inlet is configured for providing the gas within the volume . For example , the gas inlet is an opening in the housing through which the gas can flow into the volume . For instance , the gas inlet can be arranged in or be a side of the housing . In this instance , a part of the side of the housing or the entire side of the housing can be free of a material of the housing . For example , gas inlet is arranged in a side of the housing opposite the substrate . Alternatively, the gas inlet can be arranged in a side of the housing di f ferent from the side opposite the substrate . A gas inlet is a simple way for providing the gas within the volume .

[0026] According to at least one embodiment , the gas inlet comprises at least one cavity in at least one side of the housing, wherein a layer of a material of the housing remains between the cavity and the measurement unit . In particular, the housing is formed as a conformal coating of the radiationemitting element , the measurement unit , the detector unit , and the reflection prism . In this instance , the material of the housing can be permeable for the gas , in particular for a thin layer of the material of the housing . The gas can enter the cavity from the outside and di f fuse through the layer of the material of the housing to the measurement unit . In particular, the at least one cavity is arranged in a side of the housing opposite the substrate . A gas inlet comprising a cavity and a layer of the material of the housing can advantageously be stable and provide a protection against an interfering influence of external electromagnetic radiation . Furthermore , the housing can advantageously be more robust .

[0027] According to at least one embodiment , the gas inlet is covered with a covering impermeable to the electromagnetic radiation emitted by the radiation-emitting element . In particular, the covering is permeable for the gas . In other words , the gas can pass through the covering, whereas electromagnetic radiation having at least the wavelength or the wavelength range of the electromagnetic radiation emitted by the radiation-emitting element cannot pass through the covering . For example , the covering is impermeable for an external electromagnetic radiation from radiation sources outside the optoelectronic device , in particular external electromagnetic radiation having at least the wavelength or the wavelength range emitted by the radiation-emitting element . A covering on the gas inlet can advantageously be stable and provide a protection against an interfering influence of external electromagnetic radiation .

[0028] According to at least one embodiment , the covering comprises a meander perforated plate , an inverse opal layer, a foamed plastic layer, or at least three layers of a perforated metal sheet .

[0029] For example , a meander perforated plate comprises pores through the plate that are not straight , but bend . In this instance , gas can pass through the pores in the meander perforated plate , whereas the meander perforated plate is impermeable for electromagnetic radiation .

[0030] For example , an inverse opal layer comprises a regular arrangement of spherical void spaces surrounded by solid walls . The inverse opal layer is produced, for instance , by sel f-assembling a sacri ficial material such as polystyrene spheres , depositing a metal such as nickel or copper in the void spaces between the sacri ficial material , and removing the sacri ficial material to leave a three-dimensionally ordered porous solid .

[0031] For example , the foamed plastic layer comprises a plastic material having pores permeable for the gas . Th plastic material can be a thermoplastic resin such as polycyclohexylenedimethylene terephthalate ( PCT ) , polybutylene terephthalate ( PBT ) , or polyphthalamide ( PPA) or a thermosetting resin such as epoxy . Thermoplastic resins and thermosetting resins can advantageously be stable at temperatures required for SMT-mounting of the optoelectronic device , for example for SMT-mounting with SnAgCu at 260 ° C . The foamed plastic layer can be produced by foam inj ection molding thereby producing a foam structure comprising the pores . In particular, the foam structure is present on all sides and intrinsically . The pores can be incorporated in the plastic material by physical methods such as in introduction of gas cavities in liquid plastic or chemical methods such as a gas production at elevated temperatures by a chemical reaction . For example , sodium carbonate is used in the chemical methods .

[0032] For example , the at least three layers of a perforated metal sheet are arranged on top of one another in such a way that openings of a layer partially overlap with openings of directly adj acent layers in such a way that there is no overlap of openings of three directly adj acent layers . For instance , openings of a first layer overlap with openings of a second layer and openings of the second layer overlap with openings of a third layer, but openings of the second layer do not overlap with openings of the first layer and the third layer at the same time . As a result , gas can permeate the covering, whereas electromagnetic radiation cannot permeate the covering . For example , the covering can comprise more than three layers of a perforated metal sheet such as four layers or five layers . In particular, the at least three layers of the perforated metal sheet are bonded to one another by means of adhering, soldering, or sintering . In these instances , an adhesive , a solder material , or a sintering material , respectively, are applied on the perforated metal sheets that are subsequently used to bond the layers together, for example by means of an elevated temperature . Alternatively, tinned metal sheets can be used and a further adhesive , solder material or sintering material can be dispensed with . Alternatively, the perforated metal sheets can be bonded by means of welding, in particular spot welding, for example laser spot welding or electrode spot welding . In this instance , the layer can be spot welded at every tenth location at which all layers are present .

[0033] According to at least one embodiment , the detector unit comprises an integrated circuit . In particular, the integrated circuit is configured for controlling the optoelectronic device , in particular the radiation-emitting element , for signal processing of the measurement signal and the reference signal , and for outputting a measurement result . Signal processing can include an analysis of the measurement signal and the reference signal and a determination of the measurement result . In particular, the integrated circuit is a monolithic integrated circuit . For example , the integrated circuit is an application-speci fic integrated circuit (AS IC ) . For instance , the first photodetector region and the second photodetector region are both arranged on a surface of the integrated circuit . An integrated circuit can advantageously combine the optical measurement and the signal processing in one compact optoelectronic device . Using a cost-ef ficient and standardi zed integrated circuit advantageously facilitates the integration of the optoelectronic device in a control system of for example a heating system .

[0034] According to at least one embodiment , the measurement region and / or the reference region are arranged on at least one side of the reflection prism . In particular, the measurement region and / or the reference region are arranged in direct contact to the reflection prism . For example , the reflection prism is configured as a carrier for the measurement region and / or the reference region . For instance , the reflection prism is impermeable for the gas . By using a reflection prism as the carrier for the measurement region and the reference region, additional carriers such as plates can advantageously be dispensed with . Thus , the optoelectronic device can be provided cost-ef f iciently .

[0035] According to at least one embodiment , the measurement region and / or the reference region comprises a measurement stack, and a protective layer . The measurement stack is arranged between the reflection prism and the protective layer . In particular, the reflection prism, the measurement stack, and the protective layer are arranged in such a way that the reflection prism and the protective layer are in direct mechanical contact in a region laterally surrounding the measurement stack . Thus , the measurement stack is surrounded by the reflection prism and the protective layer from all sides .

[0036] In particular, the measurement stack is configured for interacting with the gas . For example , gas molecules bind to and / or chemically react with the material of the measurement stack . The binding and / or chemical reaction can cause a change of a transmission of the electromagnetic radiation through the measurement region of the measurement unit . In particular, the measurement stack comprises or consists of a metal or metal alloy . For example , the measurement stack comprises or consists of a magnesium alloy such as a Pd-capped Mg82Tii8alloy, a Mg82Zri8alloy, a Pd-capped YsoMgso alloy, a tantalum palladium alloy such as Tao. gPdo. i , or a palladium gold copper alloy such as Pdo.5Auo.35Cuo. o5 • In the case of the gas being hydrogen, hydrogen reacts with a metal that is present in the measurement stack thereby forming metal hydrides . The metal hydrides can absorb a part of the electromagnetic radiation of the first beam path thereby, for example , changing the intensity of the measurement signal . In particular, the formation of metal hydrides changes a transparency of the measurement region depending on the amount of hydrogen gas present in the optoelectronic device .

[0037] In particular, the measurement stack comprises at least one measurement layer . For example , the measurement stack comprises one measurement layer, two measurement layers or more than two measurement layers . Here and in the following, measurement layers are layers of the measurement stack, in particular metal layers or metal alloy layers , without protective layers . It is possible that not all materials suitable for the measurement stack adhere equally well to one another and / or to the reflection prism and / or the protective layer . By using at least one measurement layer in the measurement stack, an adhesion of the components and layers of the measurement unit can advantageously be enhanced and tailored to speci fic applications .

[0038] For example , the measurement stack comprises at least a first measurement layer and a second measurement layer arranged between the first measurement layer and the protective layer . For example , the first measurement layer and the second measurement layer comprise or consist of a metal or a metal alloy . For instance , the metal alloy is a tantalum palladium alloy such as Tao . gPdo . i or a palladium gold copper alloy such as Pdo. eAuo. ssCuo. os • A measurement stack comprising a first measurement layer of a tantalum palladium alloy such as Tao . gPdo . i and a second measurement layer of a palladium gold copper alloy such as Pdo. eAuo.35Cuo. o5 is advantageously suited for detecting hydrogen gas .

[0039] In particular, the protective layer is configured for protecting the measurement stack against damage . For example , the protective layer is permeable for the gas , in particular for hydrogen . Thus , during operation of the optoelectronic device , the measurement region comes into contact to the gas . The gas can pass through the protective layer to reach the measurement stack in the measurement region . The gas can interact with the measurement stack and create a measurement signal at the first photodetector region . For example , the protective layer comprises or consists of polytetrafluoroethylene ( PTFE ) . PTFE can advantageously provide an improved gas selectivity for hydrogen gas .

[0040] According to at least one embodiment , the reference region further comprises a gas-impermeable layer . The gas- impermeable layer is arranged between the measurement stack and the protective layer . In other words , the reference region comprises the measurement stack, the gas-impermeable layer, and the protective layer in this order . For instance , the gas-impermeable layer comprises or consists of silicon dioxide ( SiO2) .

[0041] In particular, the gas-impermeable layer is configured in such a way that the gas passes through the gas-impermeable layer signi ficantly slower than through the protective layer . It should be noted that the gas-impermeable layer may not be completely impermeable for the gas . However, a gas transport through the gas-impermeable layer is very slow compared to any layers described herein as gas-permeable . For example , the reflection prism, the measurement stack, and the gas- impermeable layer are arranged in such a way that the reflection prism and the gas-impermeable layer are in direct mechanical contact in a region laterally surrounding the measurement stack . Thus , the measurement stack is surrounded by the reflection prism and the gas-impermeable layer from all sides . During operation of the optoelectronic device , the reference region comes into contact to the gas . However, due to the gas-impermeable layer, the gas cannot pass through the gas-impermeable layer and through the reflection prism at a first contact of the gas to the reference region . Thus , the gas cannot reach the measurement stack in the reference region at the same time that the gas reaches the measurement stack in the measurement region . Thus , i f a gas comes into contact with the measurement unit for the first time , the measurement signal is di f ferent from the reference signal and the optoelectronic device determines a measurement result that indicates the presence of the gas . A reference region with a gas impermeable layer advantageously allows to perform reference measurements and thus increase the signal-to-noise ratio .

[0042] In particular, the reference region only di f fers from the measurement region in the presence of the gas-impermeable layer . Thus , the electromagnetic radiation passes through a similar layer stack along the first beam path and along the second beam path . This advantageously ensures a more accurate measurement result .

[0043] According to at least one embodiment , the reflection prism comprises a transmissive side and a first reflective side and a second reflective side . In particular, electromagnetic radiation enters the reflection prism through the transmissive side , is at least partially reflected at the first reflective side , subsequently at least partially reflected at the second reflective side , and exits the reflection prism through the transmissive side .

[0044] According to at least one embodiment , the transmissive side is located on a side of the reflection prism facing the radiation-emitting element and the detector unit . Thus , the electromagnetic radiation emitted by the radiation-emitting element can advantageously enter the reflection prism simply and ef ficiently .

[0045] According to at least one embodiment , the first reflective side is located on a side of the reflection prism facing away from the radiation-emitting element and the detector unit and the first reflective side is arranged above the radiationemitting element .

[0046] According to at least one embodiment , the second reflective side is located on a side of the reflection prism facing away from the radiation-emitting element and the detector unit and the second reflective side is arranged above the detector unit .

[0047] According to at least one embodiment , the measurement region and / or the reference region is arranged on the transmissive side of the reflection prism . The measurement region and / or the reference region can advantageously be arranged on the transmissive side of the reflection prism in a simple manner .

[0048] In particular, the measurement region and / or the reference region covers only a part of the transmissive side in such a way that the electromagnetic radiation emitted by the radiation-emitting element is transmitted through the measurement region and / or the reference region only once . For example , the measurement region and / or the reference region is arranged on a part of the transmissive side facing the radiation-emitting element or on a part of the transmissive side facing the detector unit . As beam paths transmitted through the measurement region and / or the reference region can comprise an increased radiation loss , having beam paths with only one transmission can advantageously be reali zed without increasing the power of the radiation-emitting element .

[0049] Alternatively, the measurement region and / or the reference region can completely cover the transmissive side . In this instance , the electromagnetic radiation emitted by the radiation-emitting element is transmitted through the measurement region and / or the reference region twice . Beam path having two transmissions through the measurement region and / or the reference region can require an increased power of the radiation-emitting element . However, by completely covering the transmissive side , the sensitivity of the optoelectronic device can advantageously be increased .

[0050] According to at least one embodiment , the measurement region and / or the reference region is arranged at least on the first reflective side or the second reflective side . In particular, the measurement region and / or the reference region completely covers the first reflective side or the second reflective side . Arranging the measurement region and / or the reference region on a reflective side of the reflection prism can change the properties of the reflective side in such a way that a reflection of the electromagnetic radiation on the reflective side is not a total internal reflection . Instead, at least a part of the electromagnetic radiation can pass through the reflective side and enter the measurement region and / or the reference region on the reflective side . The electromagnetic radiation can then be reflected inside the measurement region and / or reference region at least partially . In particular, the reflective side not covered by the measurement region and / or the reference region is free of the measurement unit . In this instance , the electromagnetic radiation is reflected on this reflective side . As the measurement region and / or the reference region can reflect a large amount of the electromagnetic radiation that enters the measurement region and / or the reference region, the power consumption of the optoelectronic device can advantageously be decreased and a sensitivity of the optoelectronic device can be increased .

[0051] According to at least one embodiment , the measurement region and / or the reference region is arranged on the first reflective side and the second reflective side . In particular, the first reflective side and the second reflective side are completely covered by the measurement region and / or the reference region . Arranging the measurement region and / or the reference region on the first reflective side and the second reflective side can advantageously increase the sensitivity of the optoelectronic device .

[0052] According to at least one embodiment , the measurement region and / or the reference region is arranged on the transmissive side , the first reflective side , and the second reflective side . In particular, all rectangular sides of the reflection prism are covered, in particular completely, by the measurement region and / or the reference region . In this instance , the beam paths of the electromagnetic radiation are both transmissive and reflective . Having transmissive and reflective beam paths can increase the power consumption of the radiation-emitting element of the electronic device . However, arranging the measurement region and / or the reference region on the transmissive side , the first reflective side , and the second reflective side can advantageously provide a very sensitive optoelectronic device .

[0053] According to at least one embodiment , the first beam path and the second beam path are reflective . In particular, for measuring the measurement signal and the reference signal , electromagnetic radiation is used that is reflected as it passes along the first beam path or the second beam path, respectively . For example , the electromagnetic radiation is reflected in the measurement unit , in particular in the measurement region or the reference region, respectively . For instance , at least 80 % , in particular at least 90 % , of the electromagnetic radiation entering the measurement unit is reflected inside the measurement unit .

[0054] In particular, the first beam path is configured in such a way that the electromagnetic radiation enters the measurement region from a side facing the radiation-emitting element , is at least partially reflected inside the measurement region, and exits the measurement region on the side facing the radiation-emitting element . In other words , the measurement of the measurement signal is performed in reflection .

[0055] In particular, the second beam path is configured in such a way that the electromagnetic radiation enters the reference region from a side facing the radiation-emitting element , is at least partially reflected inside the reference region, and exits the reference region on the side facing the radiation- emitting element . In other words , the measurement of the reference signal is performed in reflection .

[0056] In particular, the reflection of the electromagnetic radiation is specular or di f fuse . A specular reflection can be achieved by a smooth or smoothed surface . A di f fuse reflection can be achieved by a rough or roughened surface . The smooth or smoothed surface or the rough or roughened surface can be a part of the measurement unit , in particular of the measurement region or the reference region, respectively .

[0057] As the measurement unit can reflect a large amount of the electromagnetic radiation that enters the measurement unit such as at least 80% , the power consumption of the optoelectronic device can advantageously be decreased and a sensitivity of the optoelectronic device can be increased by using reflective beam paths .

[0058] According to at least one embodiment , the first beam path and the second beam path are transmissive . In this instance , the measurement region and / or the reference region is arranged on the transmissive side of the reflection prism . The first beam path and the second beam path can be configured in such a way that the electromagnetic radiation passes through the measurement region and / or the reference region, in particular through the measurement unit , only once or only twice . In other words , the measurement of the measurement signal and / or the measurement of the reference signal is performed in transmission . By arranging the measurement unit in the beam paths between radiation-emitting element and detector unit , the measurements of the measurement signal and the reference signal are performed in transmission thereby using an uncomplicated and thus reliable measurement method .

[0059] According to at least one embodiment , the first beam path and the second beam path are reflective and transmissive . In this instance , the measurement region and / or the reference region is arranged on the transmissive side and at least one of the first reflective side and the second reflective side . In particular, all rectangular side surfaces of the reflection prism are covered by the measurement region and / or the reference region . Having reflective and transmissive beam paths can advantageously provide a very sensitive optoelectronic device .

[0060] According to at least one embodiment , the measurement region and the reference region are arranged directly adj acent to one another . In particular, the measurement region and the reference region are arranged on the same reflection prism . The measurement stack can be formed as a two-part measurement stack with the two parts arranged directly adj acent to one another on the same reflection prism . One of the two parts can form the measurement region and the other part can form the reference region . The protective layer can also be formed as a two-part protective layer or as one protective layer covering both parts of the two-part measurement stack . The reference region further comprises the gas-impermeable layer . The first photodetector region and the second photodetector region can also be arranged adj acent to one another . In order to ensure an optical separation of the first beam path and the second beam path and to increase the sensitivity of the optoelectronic device , the first photodetector region and the second photodetector region can be spaced apart within the detector unit . For example , the first photodetector region and the second photodetector region can be arranged on the integrated circuit with a part of the integrated circuit between the first photodetector region and the second photodetector region being free of a photodetector region . For example , the first beam path and the second beam path are parallel to one another . A measurement unit having the measurement region and the reference region directly adj acent to one another can advantageously be produced and mounted easily and cost-ef f iciently .

[0061] According to at least one embodiment , the optoelectronic device comprises a further reflection prism . In particular, the further reflection prism comprises the same properties and configurations as the reflection prism . Features and embodiments described in conj unction with the reflection prism also apply to the further reflection prism and vice versa . For example , the further reflection prism can be arranged parallel to the reflection prism . For instance , the triangular side surfaces of the reflection prism and the further reflection prism are parallel to one another . The reflection prism and the further reflection prism can be arranged congruently . Thus , in plan view of the triangular side surfaces , the reflection prism and the further reflection prism overlap, in particular completely . Alternatively, the further reflection prism can be shi fted in relation to the reflection prism in a direction of the main extension direction of the substrate . In this instance , in plan view of the triangular side surfaces , the reflection prism and the further reflection prism at most partially overlap, for example in a location above the radiationemitting element . Here , the detector unit can be formed as a two-part detector unit and the radiation-emitting element can be arranged between the two parts of the detector unit . According to at least one embodiment , the measurement region is arranged on the reflection prism, and the reference region is arranged on the further reflection prism . In particular, the measurement region and the reference region are spatially separated . Arranging the measurement region and the reference region on di f ferent reflection prisms can advantageously ensure an optical separation of the first beam path and the second beam path and thus a precise and reliable measurement .

[0062] According to at least one embodiment , the reflection prism and the further reflection prism are optically separated . For example , the reflection prism and further reflection prism are arranged parallel and congruently to one another . To optically separate the reflection prism and the further reflection prism, the prisms can be spaced apart from one another . A space between the reflection prism and a further reflection prism can advantageously optically separate the first beam path and the second beam path . Alternatively, the reflection prism and a further reflection prism can optically be separated by means of an adhesive configured to absorb electromagnetic radiation emitted by the radiation-emitting element . In particular, the adhesive covers the triangular side surfaces of the reflection prism and the further reflection prism facing one another . For example , the adhesive is a black adhesive . By optically separating the reflection prisms , the beam paths for creating the measurement signal and for creating the reference signal can advantageously be separated simply and cost-ef f iciently . This can ensure a precise and reliable measurement . Further, crosstalk between the measurement signal and the reference signal can be reduced or prevented . According to at least one embodiment , at least one mirror layer is arranged on at least one triangular side of the reflection prism and / or the further reflection prism . In particular, the mirror layer is configured for reflecting the electromagnetic radiation emitted by the radiation-emitting element . For example , both triangular sides of the reflection prism and / or the further reflection prism are covered, in particular completely, by a mirror layer . For instance , the triangular sides of the reflection prism and the further reflection prism facing one another are covered with a mirror layer and bonded together by means of an adhesive . A mirror layer on a triangular side of the reflection prism and / or the further reflection prism can advantageously increase an optical separation of the first beam path and the second beam path, ensure a precise and reliable measurement , reduce radiation losses due to outcoupling via the triangular side and / or absorption, and increase the sensitivity and accuracy of the optoelectronic device .

[0063] According to at least one embodiment , the reflection prism is mounted on the radiation-emitting element and the detector unit . For example , the reflection prism is mounted on the radiation-emitting element and the detector unit by means of a transparent adhesive . By mounting the reflection prism on the radiation-emitting element and the detector unit , advantageously no separate supporting fixture for the reflection prism and thus the measurement unit is needed and the coupling of the electromagnetic radiation into the reflection prism is improved .

[0064] According to at least one embodiment , the radiation-emitting element and the detector unit are mounted on the substrate . In particular, the first photodetector region and / or the second photodetector region are arranged in the detector unit on a side of the detector unit facing away from the substrate . For example , the integrated circuit of the detector unit is mounted on the substrate and the first photodetector region and the second photodetector region are arranged on a side of the integrated circuit facing away from the substrate . By mounting the radiation-emitting element and the detector unit on the substrate , electrical contacts can advantageously easily be established through the substrate and the optoelectronic device can advantageously be provided simply and cost-ef f iciently .

[0065] According to at least one embodiment , the radiation-emitting element comprises or is a micro-LED . It is also possible that the radiation-emitting element comprises or is a mini-LED . As a broad definition, a micro-LED could be seen as any lightemitting diode ( LED) with a particularly small si ze . MicroLEDs may comprise a width, a length, a thickness and / or a diameter smaller than or equal to 100 micrometers , in particular, smaller than or equal to 70 micrometers , for example smaller than or equal to 50 micrometers . In particular, micro-LEDs , for example rectangular micro-LEDs , have an edge length, in particular in plan view of the layers of the semiconductor layer sequence , of a luminous surface smaller than or equal to 70 micrometers , for example smaller than or equal to 50 micrometers . For example , a micro-LED is a light-emitting diode with a growth substrate removed, such that a thickness of the micro-LED is in the range between and including, for example , 1 . 5 micrometers and 10 micrometers . For example , the micro-LED is provided on a wafer having releasable retaining structures . The micro-LED can be detached from the wafer in a non-destructive manner . In particular, micro-LEDs are used in optoelectronic devices to provide electromagnetic radiation depending on the speci fic application . The micro-LEDs can form pixels or subpixels and can emit electromagnetic radiation of a defined color or wavelength or wavelength range . Small pixel si ze and a high density with close distances make micro-LEDs suitable , among others , for optoelectronic devices such as gas sensors for consumer applications , industrial applications , and automotive applications , for instance in fuel cells .

[0066] Advantageous embodiments and developments of the optoelectronic device for detecting a gas will become apparent from the exemplary embodiments described below in conj unction with the figures .

[0067] In the figures :

[0068] Figures 1A, 3 , 5 , 8A, and 9C each show a schematic sectional side view of an optoelectronic device for detecting a gas according to di f ferent exemplary embodiments ,

[0069] Figures IB, 7A to 7D, 8B, 9A, and 9B each show a schematic top view of an optoelectronic device according to di f ferent exemplary embodiments ,

[0070] Figures 2A, 4A to 4C, and 6A to 6C each show a schematic illustration of a measurement unit according to an exemplary embodiment ,

[0071] Figures 2B to 2D each show a schematic sectional side view of a measurement unit according to di f ferent exemplary embodiments . In the exemplary embodiments and figures , similar or similarly acting constituent parts are provided with the same reference signs . The elements illustrated in the figures and their si ze relationships among one another should not be regarded as true to scale . Rather, individual elements may be represented with an exaggerated si ze for the sake of better representability and / or for the sake of better understanding .

[0072] The optoelectronic device 1 of the exemplary embodiment shown in figures 1A and IB is configured for detecting a gas , for example hydrogen (H2) or ammonia (NH3) or a harmful gas such as SOXor NOX.

[0073] The optoelectronic device 1 is surface mountable . The optoelectronic device 1 comprises a substrate 2 , in particular a SMT-substrate , and a housing 3 , in particular an inj ection molded housing . Electrical connection pads 21 of the optoelectronic device 1 are arranged exclusively on a side of the substrate 2 facing away from the housing 3 . The housing 3 comprises a gas inlet 31 covered with a covering 32 . The covering 32 can comprise a meander perforated plate , an inverse opal layer, a foamed plastic layer, or at least three layers of a perforated metal sheet . In the exemplary embodiment of figure 1 , the gas inlet 31 is arranged in a side of the housing 3 opposite the substrate 2 . Alternatively, the gas inlet 31 can be arranged in a side of the housing 3 di f ferent from the side opposite the substrate 2 . The housing 3 as well as the covering 32 can be impermeable for electromagnetic radiation, in particular at least for an electromagnetic radiation 10 emitted by a radiation-emitting element 4 of the optoelectronic device 1 . The substrate 2 and the housing 3 surround a volume 7 . Within the volume 7 , a radiation-emitting element 4 , a measurement unit 5 , a detector unit 6 , and a reflection prism 8 are arranged . The radiation-emitting element 4 and the detector unit 6 are mounted on and electrically contacted through the substrate 2 . The reflection prism 8 is mounted on the radiation-emitting element 4 and the detector unit 6 .

[0074] The radiation-emitting element 4 is configured for emitting an electromagnetic radiation, in particular, an electromagnetic radiation in the ultraviolet wavelength range , the visible wavelength range , and / or the infrared wavelength range , for example , in the infrared wavelength range . The electromagnetic radiation is emitted by the radiation exit surface 41 .

[0075] The detector unit 6 can comprise an integrated circuit 63 . On a side of the detector unit 6 , in particular of the integrated circuit 63 , facing away from the substrate 2 , a first photodetector region 61 and a second photodetector region 62 are arranged adj acent to one another . For example , the first photodetector region 61 comprises or consists of a first photodiode and the second photodetector region 62 comprises or consists of a second photodiode . Alternatively, the first photodetector region 61 can be a first part of a two-part photodiode and the second photodetector region 62 can be a second part of the two-part photodiode .

[0076] The reflection prism 8 is a triangular prism, in particular an isosceles right-angled triangular reflection prism 8 . The reflection prism 8 comprises a transmissive side 81 , a first reflective side 82 , and a second reflective side 83 . The transmissive side 81 is located on a side of the reflection prism 8 facing the radiation-emitting element 4 and the detector unit 6 . The first reflective side 82 is located on a side of the reflection prism 8 facing away from the radiation-emitting element 4 and the detector unit 6 and is arranged above the radiation-emitting element 4 . The second reflective side 83 is located on a side of the reflection prism 8 facing away from the radiation-emitting element 4 and the detector unit 6 and is arranged above the detector unit 6 .

[0077] The measurement unit 5 is mounted on the first reflective side 82 and the second reflective side 83 . The measurement unit 5 comprises a measurement stack 53 . The measurement unit 5 is divided into a measurement region 51 and a reference region 52 . The measurement region 51 is arranged in a first beam path of the electromagnetic radiation between the radiation-emitting element 4 and the first photodetector region 61 and the reference region 52 is arranged in a second beam path of the electromagnetic radiation between the radiation-emitting element 4 and the second photodetector region 62 . In other words , in the exemplary embodiment of figures 1A and IB, the measurement region 51 is arranged above the radiation-emitting element 4 and the first photodetector region 61 and the reference region 52 is arranged above the radiation-emitting element 4 and the second photodetector region 62 . Both the first beam path and the second beam path are reflective . Thus , the measurement of a measurement signal via the first beam path and the measurement of a reference signal via the second beam path is performed in reflection as the electromagnetic radiation of the radiation-emitting element 4 is at least partially reflected inside the measurement region 51 and the reference region 52 before it reaches the first photodetector region 61 or the second photodetector region 62 , respectively .

[0078] During operation of the optoelectronic device 1 , the gas enters the volume 7 through the gas inlet 31 and comes into contact with the measurement unit 5 . The gas interacts with the measurement stack 53 in the measurement region 51 of the measurement unit 5 . For example , the gas can bind to and / or chemically react with a material of the measurement stack 53 in the measurement region 51 . As a result , a property of the electromagnetic radiation of the first beam path that is reflected in the measurement region 51 is changed . Thus , a measurement signal detected at the first photodetector region 61 is changed by the presence of the gas in the volume 7 . In the reference region 52 , the gas does not interact with the measurement stack 53 . Thus , a reference signal detected at the second photodetector region 62 remains unchanged by the presence of the gas in the volume 7 . By comparing the measurement signal to the reference signal , a measurement result can be determined indicating the presence of the gas as well as a concentration of the gas due to the detected di f ference between the measurement signal and the reference signal .

[0079] The measurement unit 5 of the exemplary embodiment shown in figure 2A corresponds essentially to the measurement unit 5 shown in figures 1A and IB . The measurement unit 5 comprises a measurement region 51 and a reference region 52 . The measurement region 51 and the reference region 52 are arranged adj acent to one another on the first reflective side 82 and the second reflective side 83 of the reflection prism 8 . Figure 2B shows a schematic sectional side view of a measurement unit 5 of figure 2A. In the dashed circle denoted A ( in the following referred to as detail A) , figure 2B shows that a part of side of the reflection prism 8 laterally surrounding the measurement stack 53 is free of the measurement stack 53 .

[0080] Figures 2C and 2D each show a schematic sectional side view of detail A as illustrated in figure 2B . Figures 2C shows a measurement region 51 , whereas figures 2D shows a reference region 52 of the measurement unit 5 .

[0081] The measurement region 51 of the exemplary embodiment shown in figure 2C comprises a measurement stack 53 and a protective layer 54 . The measurement stack 53 is arranged between the reflection prism 8 and the protective layer 54 . In the exemplary embodiment of figure 2C, the measurement stack 53 comprises a first measurement layer 531 and a second measurement layer 532 arranged between the first measurement layer 531 and the protective layer 54 . The first measurement layer 531 and the second measurement layer 532 comprise or consist of a metal or metal alloy . For example , the first measurement layer 531 comprises or consists of a tantalum palladium alloy such as Tao. gPdo. i and the second measurement layer 532 comprises or consists of a palladium gold copper alloy such as Pdo. eAuo.35Cuo. o5 • For instance , such a measurement stack 53 is configured for detecting hydrogen gas . The protective layer 54 is arranged on the measurement stack 53 in such a way that it has a direct contact to the reflection prism 8 in a region of the reflection prism 8 that is free of the measurement stack 53 . Thus , the protective layer 54 and the reflection prism 8 surround the measurement stack 53 from all sides . The protective layer 54 is permeable for the gas such that the gas can penetrate the protective layer 54 and can come into contact with the measurement stack 53 in the measurement region 51 . For example , the protective layer 54 comprises or consists of polytetrafluoroethylene ( PTFE ) .

[0082] In contrast to the measurement region 51 shown in figure 2C, the reference region 52 of the exemplary embodiment shown in figure 2D further comprises a gas-impermeable layer 55 arranged between the measurement stack 53 and the protective layer 54 . The gas-impermeable layer 55 is arranged on the measurement stack 53 in such a way that it has a direct contact to the reflection prism 8 in the region of the reflection prism 8 that is free of the measurement stack 53 . Thus , the gas-impermeable layer 55 and the reflection prism 8 surround the measurement stack 53 from all sides and thus prevent that the gas can reach the measurement stack 53 in the reference region 52 . For example , the gas-impermeable layer 55 comprises or consists of silicon dioxide ( SiCy ) .

[0083] The optoelectronic device 1 of the exemplary embodiment shown in figure 3 corresponds essentially to the optoelectronic device 1 shown in figures 1A and IB . In contrast , in the optoelectronic device 1 of figure 3 , the measurement unit 5 is arranged on the transmissive side 81 of the reflection prism 8 . Both the first beam path and the second beam path are transmissive . Thus , the measurement of a measurement signal via the first beam path and the measurement of a reference signal via the second beam path is performed in transmission as the electromagnetic radiation of the radiation-emitting element 4 is at least partially transmitted through the measurement region 51 and the reference region 52 before it reaches the first photodetector region 61 or the second photodetector region 62 , respectively .

[0084] Figure 4A to 4C show di f ferent exemplary embodiments of the measurement unit 5 as shown in conj unction with figure 3 .

[0085] In the exemplary embodiment of figure 4A, the transmissive side 81 of the reflection prism 8 is completely covered by the measurement region 51 and the reference region 52 . The measurement region 51 and the reference region 52 are arranged adj acent to one another .

[0086] In the exemplary embodiment of figure 4B, only a part of the transmissive side 81 of the reflection prism 8 is covered by the measurement region 51 and the reference region 52 . The measurement region 51 and the reference region 52 are arranged adj acent to one another . In the exemplary embodiment of figure 3 , the part covered by the measurement region 51 and the reference region 52 is arranged above the radiationemitting element 4 and a part of the reflection prism that is free of the measurement region 51 and the reference region 52 is arranged above the detector unit 6 .

[0087] In the exemplary embodiment of figure 4C, only a part of the transmissive side 81 of the reflection prism 8 is covered by the measurement region 51 and the reference region 52 . The measurement region 51 and the reference region 52 are arranged adj acent to one another . In the exemplary embodiment of figure 3 , the part covered by the measurement region 51 and the reference region 52 is arranged above the detector unit 6 and a part of the reflection prism that is free of the measurement region 51 and the reference region 52 is arranged above the radiation-emitting element 4 . The optoelectronic device 1 of the exemplary embodiment shown in figure 5 corresponds essentially to the optoelectronic devices 1 shown in figures 1A and IB as well as in figure 3 . In contrast , in the optoelectronic device 1 of figure 5 , the measurement unit 5 is arranged on the transmissive side 81 , the first reflective side 82 , and the second reflective side 83 of the reflection prism 8 . In other words , all rectangular side surfaces of the reflection prism 8 are covered with the measurement unit 5 . Both the first beam path and the second beam path are transmissive and reflective .

[0088] Figure 6A to 6C show an exemplary embodiment of the measurement unit 5 as shown in conj unction with figure 5 . Figure 6A shows a view of the transmissive side 81 , figure 6B shows a view of the first reflective side 82 , and figures 6C shows a view of the second reflective side 83 . The sides 81 , 82 , 83 are completely covered with the measurement region 51 and the reference region 52 . The measurement region 51 and the reference region 52 are arranged adj acent to one another on all sides 81 , 82 , 83 .

[0089] The optoelectronic device 1 of the exemplary embodiment shown in figure 7A corresponds essentially to the optoelectronic device 1 shown in conj unction with figures 1A and IB . In contrast , the exemplary embodiment of figure 7A comprises a further reflection prism 9 . The measurement region 51 is arranged on the reflection prism 8 and the reference region 52 is arranged on the further reflection prism 9 . Therefore , the reflection prism 8 is arranged on the radiation-emitting element 4 and the first photodetector region 61 and the further reflection prism 9 is arranged on the radiationemitting element 4 and the second photodetector region 62 .

[0090] The reflection prism 8 and the further reflection prism 9 are arranged adj acent to one another in such a way that they are parallel and congruent . The reflection prism 8 and the further reflection prism 9 are spaced apart in order to optically separate the reflection prism 8 and the further reflection prism 9 .

[0091] The optoelectronic device 1 of the exemplary embodiment shown in figure 7B corresponds essentially to the optoelectronic device 1 shown in conj unction with figure 7A. In contrast , the reflection prism 8 and the further reflection prism 9 are optically separated by means of an adhesive 10 that is absorbing for electromagnetic radiation emitted by the radiation-emitting element 4 . The adhesive 10 is arranged and bonds together the triangular side surfaces of the reflection prism 8 and the further reflection prism 9 that are facing each other .

[0092] The optoelectronic device 1 of the exemplary embodiment shown in figure 7C corresponds essentially to the optoelectronic device 1 shown in conj unction with figure 7A. In addition, a mirror layer 11 is arranged on each triangular side surface of the reflection prism 8 and the further reflection prism 9 . The mirror layers 11 are configured to be reflective for electromagnetic radiation emitted by the radiation-emitting element 4 . Thus , the mirror layers optically separate the reflection prism 8 and the further reflection prism 9 and can prevent radiation losses .

[0093] The optoelectronic device 1 of the exemplary embodiment shown in figure 7D corresponds essentially to the optoelectronic device 1 shown in conj unction with figure 7B . In addition, a mirror layer 11 as described in conj unction with figures 7C is arranged on each triangular side surface of the reflection prism 8 and the further reflection prism 9 . In addition, the reflection prism 8 and the further reflection prism 9 are bonded together with the adhesive 10 .

[0094] The optoelectronic device 1 of the exemplary embodiment shown in figures 8A and 8B corresponds essentially to the optoelectronic device 1 shown in conj unction with figure 7A. In contrast , the reflection prism 8 and the further reflection prism 9 are parallel and shi fted with regard to one another . Further, the detector unit 6 is formed as a two- part detector unit . One part of the detector unit 6 comprising the first photodetector region 61 is arranged on one side of the radiation-emitting element 4 and the other part of the detector unit 6 comprising the second photodetector region 62 is arranged on the other side of the radiation-emitting element 4 . The reflection prism 8 on which the measurement region 51 is mounted is arranged on the radiation-emitting element 4 and the first photodetector region 61 and the further reflection prism 9 on which the reference region 52 is mounted is arranged on the radiationemitting element 4 and the second photodetector region 62 .

[0095] The optoelectronic device 1 of the exemplary embodiment shown in figures 9A to 9C corresponds essentially to the optoelectronic device 1 shown in conj unction with figures 1A and IB . Figure 9A shows a top view of the optoelectronic device 1 without the housing 3 , figure 9B shows a top view of the optoelectronic device 1 with the housing 3 , and figure 9C shows a sectional side view of figure 9B .

[0096] The housing is formed as a conformal coating of the radiation-emitting element 4 , the measurement unit 5 , the detector unit 6 , and the reflection prism 8 . The housing 3 comprises two cavities 33 in a side of the housing facing away from the substrate 2 . A layer 34 of material of the housing 3 remains between the cavities 33 and the measurement unit 5 of the optoelectronic device 1 . The material of the housing 3 , in particular in the form of the layer 34 between the cavities 33 in the measurement unit 5 is permeable for the gas . The cavities 33 and the layers 34 of material of the housing 3 form the gas inlet 31 of the housing 3 . The gas can enter the cavities 33 from the outside and di f fuse through the layer 34 of the material of the housing 3 to the measurement unit 5 .

[0097] The features and exemplary embodiments described in connection with the figures can be combined with each other according to further exemplary embodiments , even i f not all combinations are explicitly described . Furthermore , the exemplary embodiments described in connection with the figures may have alternative or additional features as described in the general part .

[0098] This patent application claims the priority of German patent application 10 2024 100 851 . 2 , the disclosure content of which is hereby incorporated by reference .

[0099] The invention is not restricted to the exemplary embodiments by the description on the basis of said exemplary embodiments . Rather, the invention encompasses any new feature and also any combination of features , which in particular comprises any combination of features in the patent claims and any combination of features in the exemplary embodiments , even i f this feature or this combination itsel f is not explicitly speci fied in the patent claims or exemplary embodiments . References

[0100] 1 optoelectronic device

[0101] 2 substrate

[0102] 21 electrical connection pad

[0103] 3 housing

[0104] 31 gas inlet

[0105] 32 covering

[0106] 33 cavity

[0107] 34 layer

[0108] 4 radiation-emitting element

[0109] 41 radiation exit surface

[0110] 5 measurement unit

[0111] 51 measurement region

[0112] 52 reference region

[0113] 53 measurement stack

[0114] 531 first measurement layer

[0115] 532 second measurement layer

[0116] 54 protective layer

[0117] 55 gas-impermeable layer

[0118] 6 detector unit

[0119] 61 first photodiode

[0120] 62 second photodiode

[0121] 63 integrated circuit

[0122] 7 volume

[0123] 8 reflection prism

[0124] 81 transmissive side

[0125] 82 first reflective side

[0126] 83 second reflective side

[0127] 9 further reflection prism

[0128] 91 transmissive side

[0129] 92 first reflective side

[0130] 93 second reflective side 10 adhesive

[0131] 11 mirror layer

Claims

Claims1. An optoelectronic device (1) for detecting a gas comprising- a radiation-emitting element (4) configured for emitting an electromagnetic radiation,- a measurement unit (5) comprising a measurement region (51) and a reference region (52) ,- a detector unit (6) comprising at least a first photodetector region (61) and a second photodetector region (62) , and- a reflection prism (8) , wherein the reflection prism (8) is arranged on the radiation-emitting element (4) and the detector unit (6) , wherein the measurement region (51) is arranged in a first beam path of the electromagnetic radiation between the radiation-emitting element (4) and the first photodetector region ( 61 ) , wherein the reference region (52) is arranged in a second beam path of the electromagnetic radiation between the radiation-emitting element (4) and the second photodetector region ( 62 ) , wherein the optoelectronic device (1) is surface mountable, and wherein the measurement region (51) is configured for interacting with the gas (9) .

2. The optoelectronic device (1) according to the preceding claim, further comprising a substrate (2) , wherein electrical connection pads (21) of the optoelectronic device (1) are exclusively arranged on a side of the substrate (2) facing away from the radiation-emitting element(4) , the measurement unit (5) , the detector unit (6) , and the reflection prism (8) .

3. The optoelectronic device (1) according to at least one of the preceding claims, wherein the gas is hydrogen.

4. The optoelectronic device (1) according to at least one of the preceding claims, further comprising a housing (3) , wherein the substrate (2) and the housing (3) surround a volume ( 7 ) , wherein the radiation-emitting element (4) , the measurement unit (5) , the detector unit (6) , and the reflection prism (8) are arranged in the volume (7) .

5. The optoelectronic device (1) according to at least one of the preceding claims, wherein the housing (3) comprises a gas inlet (31) , and wherein the gas inlet (31) comprises at least one cavity (33) in at least one side of the housing (3) , wherein a layer (34) of a material of the housing (3) remains between the cavity (33) and the measurement unit (5) .

6. The optoelectronic device (1) according to at least one of the claims 1 to 4, wherein the housing (3) comprises a gas inlet (31) , and wherein the gas inlet (31) is covered with a covering (32) impermeable to the electromagnetic radiation emitted by the radiation-emitting element (4) .

7. The optoelectronic device (1) according to at least one of the preceding claims,wherein the detector unit (6) further comprises an integrated circuit ( 63 ) .

8. The optoelectronic device (1) according to at least one of the preceding claims, wherein the measurement region (51) and / or the reference region (52) are arranged on at least one side of the reflection prism (8) , wherein the measurement region (51) and / or the reference region (52) comprises a measurement stack (53) , and a protective layer (54) , wherein the measurement stack (53) is arranged between the reflection prism (8) and the protective layer (54) .

9. The optoelectronic device (1) according to the preceding claim, wherein the reference region (52) further comprises a gas- impermeable layer (55) , wherein the gas-impermeable layer (55) is arranged between the measurement stack (53) and the protective layer (54) .

10. The optoelectronic device (1) according to at least one of the preceding claims, wherein the reflection prism (8) comprises a transmissive side (81) and a first reflective side (82) and a second reflective side (83) , wherein the transmissive side (81) is located on a side of the reflection prism (8) facing the radiation-emitting element (4) and the detector unit (6) , wherein the first reflective side (82) is located on a side of the reflection prism (8) facing away from the radiationemitting element (4) and the detector unit (6) ,wherein the first reflective side (82) is arranged above the radiation emitting-element (4) , wherein the second reflective side (83) is located on a side of the reflection prism (8) facing away from the radiationemitting element (4) and the detector unit (6) , and wherein the second reflective side (83) is arranged above the detector unit (6) .

11. The optoelectronic device (1) according to the preceding claim, wherein the measurement region (51) and / or the reference region (52) is arranged on the transmissive side (81) of the reflection prism (8) , and / or wherein the measurement region (51) and / or the reference region (52) is arranged at least on the first reflective side (82) or the second reflective side (83) .

12. The optoelectronic device (1) according to at least one of the preceding claims, wherein the first beam path and the second beam path are reflective and / or transmissive.

13. The optoelectronic device (1) according to at least one of the preceding claims, wherein the measurement region (51) and the reference region (52) are arranged directly adjacent to one another.

14. The optoelectronic device (1) according to at least one of the claims 1 to 12, further comprising a further reflection prism (9) , wherein the measurement region (51) is arranged on the reflection prism (8) , andwherein the reference region (52) is arranged on the further reflection prism (9) .

15. The optoelectronic device (1) according to the preceding claim, wherein the reflection prism (8) and the further reflection prism (9) are optically separated.

16. The optoelectronic device (1) according to at least one of the claims 14 or 15, wherein at least one mirror layer (11) is arranged on at least one triangular side of the reflection prism (8) and / or the further reflection prism (9) .

17. The optoelectronic device (1) according to at least one of the preceding claims, wherein the reflection prism (8) is mounted on the radiationemitting element (4) and the detector unit (6) .

18. The optoelectronic device (1) according to at least one of the preceding claims, wherein the radiation-emitting element (4) and the detector unit (6) are mounted on the substrate (2) .

Images