Apparatus and method for monitoring the radiant temperature of a radiation-emitting device - Patents.com

Abstract

The present invention relates to an apparatus (112) for monitoring a radiation temperature of at least one radiation-emitting element (114), a heating system (110) for heating at least one radiation-emitting element (114) to emit thermal radiation at a radiation temperature, a method for monitoring the radiation temperature of at least one radiation-emitting element (114), and a method for heating at least one radiation-emitting element (114) to emit thermal radiation at a radiation temperature. The device (112) for monitoring the radiation temperature of at least one radiation-emitting element (114) comprises: - at least one light source (125), said light source being configured to emit optical radiation at least partially towards said at least one radiation emitting element (114); and at least one radiation sensitive element (126), said at least one radiation sensitive element (126) having at least one sensor area (128), said at least one sensor area (128) comprising at least one photosensitive material selected from at least one photoconductive material, said at least one sensor area (128) being designated to generate at least one sensor signal in response to an intensity of thermal radiation emitted by at least one radiation emitting element (114) and received by said sensor area (128) within at least one wavelength range, said sensor area (128) being adapted to receive at least one sensor signal in response to an intensity of thermal radiation emitted by said at least one light source (125) and received by said sensor area (128) within at least one further wavelength range; at least one radiation sensitive element (126) further configured to generate at least one further sensor signal in response to an intensity of the optical radiation received by the at least one radiation sensitive element (126), the at least one radiation sensitive element (126) being positioned such that the thermal radiation passes through the at least one transition material (116) before being received by the at least one radiation sensitive element (126), and at least one of the at least one light source (125) and the at least one radiation sensitive element (126) being positioned such that the optical radiation passes through the at least one transition material (116) and impinges on the at least one radiation emitting element (114) before being received by the at least one radiation sensitive element (126); at least one evaluation unit (138), which is configured to determine a radiation temperature of the at least one radiation-emitting element (114) by using the intensity values ​​of the thermal radiation and the light radiation; and Equipped with.

Description

[Technical field]

[0001] The present invention relates to an apparatus and method for monitoring the emission temperature of at least one radiation emitting element, as well as a heating system and method for heating at least one radiation emitting element to emit thermal radiation at an emission temperature. The method and apparatus can be used in particular to control the emission temperature of at least one cooking utensil heated on a ceramic glass countertop. However, further applications are also conceivable. [Background technology]

[0002] Monitoring the temperature of at least one object that emits thermal radiation, particularly in the infrared spectral range, through at least one transition material arranged such that the thermal radiation travels through the at least one transition material before being received by at least one radiation sensitive element generally requires knowledge of the emissivity of the at least one object. In particular, the temperature of at least one cookware measured through a ceramic glass countertop requires knowledge of the emissivity of the at least one particular cookware. As a result, the temperatures of different types of objects cannot be determined correctly in practice without repeated adjustments of the measurement settings.

[0003] US9,035,223B2 discloses an induction heating cooking device that completes preheating in a short time and maintains the temperature at the end of preheating. This induction heating cooking device includes a heating coil for induction heating a cooking container, an inverter circuit for supplying high-frequency current to the heating coil, an operation unit including an operation mode setting unit for setting the operation mode of the inverter circuit, an infrared sensor for detecting infrared rays emitted from the bottom surface of the cooking container, a control unit for controlling the output of the inverter circuit based on the output of the infrared sensor, a device including settings input to the operation unit, and a notification unit. However, only a single infrared sensor is disclosed here.

[0004] However, to determine the temperature of an object in an emissivity independent manner, multiple sensors can be used at different wavelengths and the sensor signals generated by each sensor can be combined. Contractor Report on Evaluation of Sensor and Control Technologies to Address Cooking Fires on Glass Ceramic Cooktops by Jacqueline Elder and Andrew M. Trotta, available at https: / / www.cpsc.gov / s3fs-public / pdfs / ceramic.PDF, describes a dual wavelength measurement system by CERAN®.

[0005] Sensing Systems for Glass Ceramic Cooktops, Internal MIT Media Lab Report, by J. Paradiso, L. Borque, P. Bramson, M. Laibowitz, H. Ma, M. Malinowski (July 18, 2003) describes temperature measurements on PbS-based CERAN® using two detectors, one active and one darkened to eliminate thermal effects. Thus, both documents describe dual wavelength measurements in the infrared spectral range that allow the temperature to be determined without knowing the emissivity of the cookware. US 6,169,486 B1 describes a sensor with a first wavelength range that is used to measure radiation from cookware, while a second detector with a second wavelength range is used to measure utensils.

[0006] In particular, ceramic glass cooktops are known to exhibit partial transparency to infrared radiation with wavelengths between 1 μm and 5 μm, where infrared radiation with wavelengths between 1 μm and 1.4 μm is particularly weak at temperatures near about 80° C. to 100° C., which are associated with the boiling process of aqueous liquids such as water, and infrared radiation with wavelengths between 3.4 μm and 4.2 μm, which are associated with the ignition process of oil.

[0007] Generally, temperature measurements involving ceramic glass countertops will be performed using at least one of the following approaches: - Measuring the temperature of the bottom of the ceramic glass cooktop and using this information to determine the condition of the cookware; - providing an opening in the ceramic glass countertop and installing a window having a high transmittance for infrared radiation, said window comprising sapphire or calcium fluoride, and inserting the window into the opening so that the infrared radiation emitted by the cooking appliance can be measured through the window, whereby the intensity of the infrared radiation at the position of the infrared sensor can be increased, but at the expense of a decrease in the mechanical strength of the ceramic glass countertop; - placing an infrared sensor above a ceramic glass countertop and measuring the temperature on the side of the cookware, which requires specially prepared cookware with emissivity strips on the side; It can be implemented using

[0008] WO2015 / 018891A1 discloses a method for operating a cooking device having a cooking stove and a heating device for heating a cooking area. Furthermore, a measurement system is provided which comprises a sensor device for detecting a first characteristic variable related to the temperature of the cooking area. According to the invention, a parameter is determined. The parameter describes a static characteristic of the measurement system and is taken into account for determining the temperature of the cooking area.

[0009] US10,356,853B2 discloses an induction cooking system including a base, one or more side walls, an induction coil, and an infrared temperature sensor. The base includes a base surface associated therewith, the base surface including a window disposed within the base surface. The one or more side walls define a well above the base surface, the well configured to receive a container disposed above the base surface. An induction coil is disposed within the base, the induction coil defining a first side disposed below the base surface, a second side disposed opposite the first side, and an opening disposed adjacent the window and extending from the first side toward the second side of the induction coil. An infrared temperature sensor is disposed adjacent the window and within the opening.

[0010] EP 3572730 A2 discloses remote temperature measurement of a cookware through a ceramic glass plate using an infrared sensor and taking into account the emissivity of the cookware which is continuously evaluated and taking into account the temperature of the ceramic glass plate.

[0011] The use of photovoltaic detectors other than InGaS-extended is fairly limited due to their low spectral sensitivity, but the high cost of InGaS-extended detectors means they are not commonly used in multiple sensor configurations.

[0012] Pyroelectric temperature sensors are not suitable for measuring unmodulated radiation, but the radiation emitted by cooking appliances is generally unmodulated, requiring mechanical or optical choppers, which increases the complexity and portability of the measurement setup and reduces its lifetime.

[0013] Thermopiles offer a cheaper alternative due to their broadband spectral sensitivity and ability to detect unmodulated radiation, but their detection capability is quite low compared to quantum detectors such as photovoltaic detectors, resulting in a much lower resolution.

[0014] Furthermore, at least one further object, different from the at least one cooking utensil, may be placed on the top surface of the ceramic glass countertop, especially in an accidental manner, where the at least one further object, such as a plastic container or burnt mark, placed on the ceramic glass countertop may create a fire hazard. It is therefore desirable to be able to detect such further object that may constitute a potential fire hazard and to prevent the operation of the ceramic glass countertop in such cases.

[0015] A further safety-related feature is the recognition of a boil-dry condition of an aqueous liquid, such as water. After the aqueous liquid in the at least one cookware has completely evaporated, the temperature of the at least one cookware may typically increase rapidly. Therefore, it is desirable to detect the rate at which the temperature of the at least one cookware increases in order to determine the presence of a boil-dry condition.

[0016] US6,300,606B1 discloses a method for detecting a boil-dry condition of a cooking utensil or container placed on a glass-ceramic cooking surface of a cooking unit having at least one cooking zone, comprising determining a clear criterion for the occurrence of a boil-dry condition based on a first and second derivative of the cooking zone temperature according to a three-step comparison of the cooking zone temperature and the cut-off temperature upon detection of the operation of a heating element power control device and the power input to the heating element. The occurrence of the positive first and second derivatives signals a boil-dry condition when the measured cooking zone temperature is sufficiently below the cut-off temperature and a predetermined time interval has elapsed since the last operation of the heating element control device by the operator. A device for detecting a boil-dry condition of a cooking utensil or container placed on a glass-ceramic cooking surface of a cooking unit having at least one cooking zone includes a cooking zone temperature sensor; a signal generating device for detecting the operation of the heating element power control device for the energy input to the heating element and the cut-off temperature; and a control and analysis device for receiving these input signals and using the input signals to generate a control signal indicative of a boil-dry condition according to the above-mentioned method. However, no specific sensor type is mentioned here.

[0017] JP 2011-138733A discloses an induction heating cooker including a top plate, a coil, an infrared sensor, a wavelength selection filter, a differential processing circuit, and a temperature calculation means. The top plate may include glass ceramic. The infrared sensor may include a photodiode. The wavelength selection filter may include a short-pass filter, a long-pass filter, or a band-pass filter. The first wavelength selection filter selectively transmits a first wavelength range, and the second wavelength selection filter selectively transmits a different second wavelength range. The differential processing circuit determines a difference between the outputs of the infrared sensor. The temperature calculation means refers to the output of the infrared sensor for calculating the temperature of the heated object and the output of the differential processing circuit.

[0018] JP 2003-109736A discloses a cooking heater device including an infrared intensity detection means, a coil, a power supply, and a control circuit. The control circuit includes a temperature detection means for detecting the temperature of an object to be heated, and an output control means. The detection means detects radiation received through a top plate and a window of a filter, respectively. Infrared intensity is detected in at least two different wavelength ranges, which are used for temperature detection.

[0019] JP 2006-292439A discloses a temperature detector including a substrate, a first optical system, a second optical system, a first Si photodiode, a second Si photodiode, a signal processing unit, and a temperature detection element. The optical system may be a convex lens. The Si photodiodes may have different sensitivity characteristics. A wavelength selection filter may be provided in front of the light receiving surface of each Si photodiode. The signal processing unit is connected to each Si photodiode and uses the respective photodiode outputs as inputs.

[0020] EP 2704521 A1 discloses a domestic appliance device and a method for operating the same. The device comprises a sensing unit with two light sensors and a beam splitter unit for splitting the outgoing radiation into two partial beams by a measuring point. The partial beams are additionally provided with a light sensor to be detected. The sensor unit comprises a light guide unit for guiding light from the measuring point to the beam splitter unit. The light guide unit is formed by an optical fiber. The sensing unit comprises a filter unit arranged between the beam splitter unit and the light sensors.

[0021] WO2019 / 124084A1 discloses an induction heating device including a top plate, a detection unit, an optical filter, a heating coil, a control unit, and a lens. The filter characteristic of the optical filter is switched by moving a movable structure of the optical filter formed by a MEMS device, and the spectral sensitivity characteristic of the detection unit is changed accordingly.

[0022] EP3572777A1 discloses a stove guard comprising a data processing unit and a temperature sensor arrangement for receiving thermal radiation. The temperature sensor arrangement comprises at least three detector elements. The data processing unit is configured to compare detection signals output by the different detector elements to determine the temperature of an object within the field of view. [Prior art documents] [Patent documents]

[0023] [Patent Document 1] US9,035,223B2 [Patent Document 2] US6,169,486B1 [Patent Document 3] WO2015 / 018891A1 [Patent Document 4] US10,356,853B2 [Patent Document 5] EP3572730A2 [Patent Document 6] US6,300,606B1 [Patent Document 7] JP 2011-138733A A [Patent Document 8] JP 2003-109736A [Patent Document 9] JP 2006-292439A [Patent Document 10] EP2704521A1 [Patent Document 11] WO2019 / 124084A1 [Patent Document 12] EP3572777A1 [Non-patent literature]

[0024] [Non-Patent Document 1] Contractor's Report on Evaluation of Sensor and Control Technologies for Combating Cooking Fires on Glass-Ceramic Countertops by Jacqueline Elder and Andrew M. Trotta [Non-Patent Document 2] J. Paradiso, L. Borque, P. Bramson, M. Laibowitz, H. Ma, M. Malinowski, Sensing Systems for Ceramic-Glass Countertops, MIT Media Lab Internal Report (July 18, 2003) Summary of the Invention [Problem to be solved by the invention]

[0025] Therefore, the object of the present invention is to provide an apparatus and method for monitoring the radiation temperature of at least one radiation-emitting element, as well as a heating system and method for heating at least one radiation-emitting element to emit thermal radiation at a radiation temperature, thereby at least partially overcoming the above-mentioned known technical drawbacks and shortcomings.

[0026] In particular, it is desirable to be able to monitor in a simple and easy manner the temperature of at least one object that emits thermal radiation, in particular thermal radiation in the infrared spectral range, through at least one transition material, in particular at least one cookware, in particular a ceramic glass countertop, arranged such that the thermal radiation travels through the at least one transition material, without the need to know the emissivity of the at least one object before it is received by the at least one radiation sensitive element. [Means for solving the problem]

[0027] This problem is solved by an apparatus and a method for monitoring the radiation temperature of at least one radiation-emitting element, as well as a heating system and a method for heating at least one radiation-emitting element to emit thermal radiation at a radiation temperature, which have the features of the independent claims. Preferred embodiments, which can be implemented in independent aspects or in any combination, are set out in the dependent claims and in the description.

[0028] In a first aspect of the present invention, an apparatus for monitoring a radiation temperature of at least one radiation-emitting element is disclosed, the at least one radiation-emitting element emitting thermal radiation at a radiation temperature. Thus, the apparatus comprises: - at least one light source, said light source configured to emit optical radiation at least partially towards said at least one radiation-emitting element; at least one radiation sensitive element, said at least one radiation sensitive element having at least one sensor area, said at least one sensor area being made of at least one photosensitive material selected from at least one photoconductive material; at least one of the at least one light source and at least one radiation sensitive element, the at least one sensor area being configured to generate at least one sensor signal in response to an intensity of thermal radiation emitted by at least one radiation emitting element within at least one wavelength range and received by the sensor area, the sensor area being further configured to generate at least one further sensor signal in response to an intensity of optical radiation emitted by at least one light source within at least one further wavelength range and received by the sensor area, the at least one radiation sensitive element being positioned such that the thermal radiation passes through at least one transition material before being received by the at least one radiation sensitive element, and at least one of the at least one light source and at least one radiation sensitive element being positioned such that optical radiation passes through at least one transition material and impinges on at least one radiation emitting element before being received by the at least one radiation sensitive element; at least one evaluation unit, which is configured to determine a radiation temperature of the at least one radiation-emitting element by using the intensity values ​​of the thermal radiation and the light radiation; and Equipped with.

[0029] As commonly used, the term "apparatus" refers to a spatial entity that includes at least the components listed above, where the listed components may be separate components. Alternatively, two or more components may be integrated into a common component. Furthermore, the apparatus or at least one component thereof may be integrated as a part of a further apparatus, where the further apparatus may preferably be a heating system or part thereof as described in more detail below. However, at least partial integration of the apparatus or part thereof into another further apparatus may also be possible.

[0030] As used herein, the term "thermal radiation" refers to the emission of a plurality of photons generated by at least one radiation-emitting element and having wavelengths covering at least a portion of the infrared spectral range. In general, the term "infrared" refers to wavelengths between 780 nm and 1000 μm, with wavelengths between 780 nm and 3 μm designated as "near infrared", wavelengths between 3 μm and 8 μm as "mid infrared", and wavelengths between 8 μm and 15 μm as "far infrared". In particular, wavelength ranges of 0.8 μm, 1 μm, 1.3 μm, 1.5 μm, or 2 μm to 2.5 μm, 2.8 μm, 3 μm, or 5 μm may be particularly preferred for the purposes of the present invention. However, depending on the materials used in the device, it is possible to use at least one wavelength.

[0031] As further used herein, the term "emitting thermal radiation" refers to the procedure of generating and spatially distributing by at least one radiation-emitting element a radiation flux of photons having a particular wavelength. As further used herein, the term "radiation-emitting element" refers in particular to a thermal radiation source designed to generate thermal radiation covering at least a part of the infrared spectral range defined above. In the context of the present invention, the at least one radiation-emitting element may in particular be or include at least one cooking utensil. As generally used, the term "cooking utensil" refers to a receptacle designed to be heated in order to transfer the heat received to at least one substance present in an internal volume contained in the receptacle, and by this process, the receptacle necessarily generates a part of the thermal radiation and spatially distributes it to the external volume surrounding the receptacle. Generally, the at least one cooking utensil may be selected from a pot or a frying pan, although further cooking utensils are also possible. Generally, the at least one cooking utensil may be used in at least one of a domestic, a canteen kitchen, or an industrial kitchen, but it is also possible to use in further environments such as a laboratory. In particular, at least a partition of the radiation-emitting element may emit a major portion of the thermal radiation, and the partition may more particularly be selected from a bottom portion of the radiation-emitting element that is arranged adjacent to the at least one transition material.

[0032] In general, the thermal radiation of the at least one cooking utensil can be determined in an arrangement in which the at least one cooking utensil is located on a countertop, in particular a ceramic glass countertop. However, the at least one radiation-emitting element can be or include at least one further object that can assume the position of the at least one cooking utensil on the countertop, either accidentally or intentionally, in order to be able to detect the presence of at least one further object that may constitute a potential fire hazard on the countertop and to prevent the operation of the countertop in this case. As an example, the at least one further object can be or include a plastic container or a burnt mark located on the ceramic glass countertop. However, further objects can also be possible.

[0033] As further used herein, the term "intensity" in relation to thermal radiation refers to the power of the radiation flux emitted by a radiation-emitting element per unit area. Intensity can be expressed by a spectrum, particularly for black radiation-emitting elements, where the term "spectral radiance" refers to the radiation flux emitted by a radiation-emitting element per unit solid angle, per unit area and per wavelength. Here, the spectral radiance indicates how much power emitted by a black radiation-emitting element can actually be received at a particular wavelength by a radiation-sensitive element that views the radiation-emitting element from a particular angle of view. However, for further types of radiation-emitting elements, different measures for the intensity of thermal radiation may be appropriate. As further used herein, the term "value" refers to a numerical expression of the intensity of thermal radiation.

[0034] As already mentioned above, the device according to the invention is specified for monitoring the radiation temperature of at least one radiation-emitting element. As commonly used, the term "radiation temperature" refers to the temperature at which at least one radiation-emitting element is generating the corresponding thermal radiation. As is particularly known to those skilled in the art, the distribution of the intensity of the thermal radiation over wavelength depends on the radiation temperature. In the particular example of a black radiation-emitting element shown above, the spectral radiance of the radiation-emitting element versus wavelength at the radiation temperature follows Planck's law. However, for other types of radiation-emitting elements, in general, the distribution of the intensity of the thermal radiation over wavelength also depends on the corresponding radiation temperature.

[0035] Further, as generally used, the term "monitoring" or grammatical variations thereof refers to a process of determining at least one piece of information without user intervention from at least one piece of data, which may in particular be continuously acquired data, and the term "measuring" relates to a process of continuously acquiring data without user intervention. For this purpose, a plurality of sensor signals may be generated and evaluated, from which at least one piece of information may be determined. In particular, the plurality of sensor signals may be recorded and / or evaluated within at least one of a fixed or variable time interval or, alternatively or additionally, upon the occurrence of at least one pre-specified event, such as the presence of at least one further object, which may be detected accidentally or intentionally, as described in more detail below.

[0036] The device comprises at least one light source. As used herein, the term "light source" refers to a device or element configured to emit optical radiation, in particular optical radiation in at least one of the optical and infrared spectral ranges. Thus, the at least one light source may be configured to provide sufficient emission in a desired spectral range, preferably in the optical and / or infrared spectral ranges, or at least one selected partition thereof. The at least one light source may in particular be comprised in at least one of a thermal radiator or a semiconductor-based radiation source. Here, the semiconductor-based radiation source may in particular be selected from at least one of a light-emitting diode (LED) or a laser, in particular a laser diode. Furthermore, the thermal radiator may in particular be selected from at least one of an incandescent lamp or a thermal infrared emitter. Thus, the light source may be or may include an incandescent lamp or a thermal infrared emitter. As further used herein, the term "thermal infrared emitter" refers to a micromachined thermal radiating device comprising a radiation emitting surface as a radiation emitting element that emits the optical radiation to be monitored. In particular, thermal infrared emitters are available from Axetris AG, Schwarzenbergstrasse 10, CH-6056 Kaegiswil, Switzerland under the name "emirs50", from LASER COMPONENTS GmbH, Werner-von-Siemens-Str.15 82140 Olching, Germany under the name "Thermal Infrared Emitter", or from Hawkeye Technologies, 181 Research Drive #8, Milford CT 06460, USA under the name "Infrared Emitter". However, further types of light sources are possible.

[0037] The at least one light source may be a continuous light source or may be a pulsed light source, which may have a modulation frequency of at least 1 Hz, at least 5 Hz, at least 10 Hz, at least 50 Hz, at least 100 Hz, at least 500 Hz, at least 1 kHz, or more. To drive the pulsed light source, a modulation device may be used, which may be designated to modulate the illumination, preferably by generating a periodic modulation. As commonly used, the term "modulation" refers to a process in which the total power of the illumination is preferably varied periodically, in particular with at least one modulation frequency. In particular, the periodic modulation may be performed between a maximum and a minimum value of the total power of the illumination. The minimum value may be 0, but may also be >0, as an example, so that a complete modulation does not have to be performed. The modulation may be performed within the radiation source designated to generate the desired modulated illumination, preferably by at least one radiation-emitting element itself having a modulated intensity and / or total power, for example a periodically modulated total power, and / or by at least one radiation-emitting element being embodied as a pulsed radiation source, for example a pulsed laser. As a further example, WO2021 / 110721A1 discloses at least one light source or radiation-emitting element designed to generate optical radiation when heated by an electric current; a mount, the mount carrying at least one radiation-emitting element, the mount or a part of which is movable; and a heat sink designed to cool the mount and the at least one radiation-emitting element carried by the mount when the heat sink is contacted by the mount. Alternatively or additionally, different types of modulation devices can also be used, for example modulation devices based on the electro-optical effect and / or the acousto-optical effect. Furthermore, a periodic beam interruption device can also be used, in particular at least one of a beam chopper, an interruption blade or an interruption wheel.

[0038] For the purpose of monitoring the radiation temperature of the at least one radiation-emitting element, the device comprises at least one radiation-sensitive element. As used herein, the term "radiation-sensitive element" refers to an element of the device designated to generate at least one sensor signal in response to the reception of radiation by the radiation-sensitive element or a part thereof. As further used herein, the term "sensor signal" refers to an electrical signal generated by the at least one radiation-sensitive element upon irradiation by radiation. Here, the sensor signal may be or include a digital signal and / or an analog signal. In particular, the sensor signal may be or include a voltage signal and / or a current signal. Additionally or alternatively, the sensor signal may be or include digital data. The sensor signal may include a single signal value and / or a series of signal values. The sensor signal may further include any signal generated by combining at least two individual signals, such as in particular by averaging at least two signals and / or forming a ratio of at least two signals.

[0039] As already indicated above, the at least one radiation sensitive element is selected from a radiation sensor having at least one sensor area. As used herein, the term "sensor area" refers to a portion of the at least one radiation sensitive element designated to receive radiation so as to trigger the generation of at least one sensor signal, the generation of which may be governed by a defined relationship between the sensor signal and the manner of illumination of the sensor area. Here, the sensor area may be a uniform sensor area or may comprise a radiation sensitive array that may be divided into a number of radiation sensitive pixels. The at least one sensor signal may be generated depending on the intensity of the thermal radiation emitted by the at least one radiation emitting element and received by the sensor area, the sensor signal may be any signal indicative of the intensity of the incident thermal radiation illuminating the sensor area.

[0040] For the purpose of generating a sensor signal upon illumination, the sensor area comprises a photosensitive material, the photosensitive material being selected from photoconductive materials. As used herein, the term "photoconductive material" refers to a material capable of sustaining an electric current and thus exhibiting a certain electrical conductivity, in particular the electrical conductivity being dependent on the illumination of the material. In such a material, an electric current can be conducted through the material via at least one first electrical contact to at least one second electrical contact and vice versa. For this purpose, at least two separate electrical contacts can be applied to different positions of the sensor area, in particular such that the first electrical contact and the second electrical contact are electrically insulated from each other, while each of the first electrical contact and the second electrical contact is directly connected with the sensor layer. For this purpose, the electrical contacts can comprise a deposited metal layer, which is easily provided by using at least one known deposition technique. In particular, the deposited metal layer can comprise at least one of gold, silver, aluminum, platinum, magnesium, chromium, or titanium. Alternatively, the electrical contacts can comprise a layer of graphene.

[0041] The at least one photoconductive material may preferably include at least one chalcogenide, which may preferably be selected from sulfide or selenide chalcogenides, solid solutions and / or doped variants thereof. As used herein, the term "solid solution" refers to a material in which at least one solute is contained in a solvent, thereby forming a homogeneous phase, where the crystal structure of the solvent is generally unchanged by the presence of the solute. As an example, the binary PbSe is dissolved in PbS, and the PbS 1-x Se xwhere the value of x can range from 0 to 1. As further used herein, the term "chalcogenide" refers to a compound that may contain at least one group 16 element of the periodic table other than oxides, i.e., sulfides, selenides, and tellurides. In a particularly preferred embodiment, the at least one layer of at least one photoconductive material may be lead sulfide (PbS) for wavelengths between 0.8 μm and 2.8 μm, or lead selenide (PbSe) for wavelengths between 0.8 μm and 5 μm. However, other inorganic photoconductive materials may also be possible.

[0042] According to the invention, at least one sensor area is designated to generate at least one sensor signal depending on the intensity of thermal radiation emitted by at least one radiation emitting element and received by said sensor area. Furthermore, at least one sensor area is designated to generate at least one further sensor signal depending on the intensity of thermal radiation emitted by at least one light source and received by said sensor area in at least one further wavelength range. The at least one wavelength range of thermal radiation may partially or completely include the at least one further wavelength range of optical radiation or vice versa. In a specific embodiment, the at least one wavelength range and the at least one further wavelength range may be identical. As used herein, the term "wavelength range" refers to a wavelength interval of radiation within which at least one sensor signal is generated.

[0043] As mentioned above, the at least one sensor signal may generally be generated separately for the at least one wavelength range. However, in an alternative embodiment, the at least one sensor signal may only be generated by using at least one known value for the intensity of the thermal radiation. In this way, the measurement time can be reduced. As a further alternative, the at least one known value may be used in case of currently invalid values ​​or values ​​that cannot be determined in the at least one wavelength range, in which case the at least one evaluation unit may use the at least one known value as a fallback opportunity and thus be able to generate at least one valid value for the radiation temperature at any time. Similarly, the at least one further sensor signal may generally be generated in an individual manner for the at least one further wavelength range. In another embodiment, however, the at least one further sensor signal may only be generated by using at least one known value for the intensity of the optical radiation. In this way, the measurement time can be reduced. As yet another alternative, the at least one known value can be used if there is currently an invalid value or a value cannot be determined in the at least one further wavelength range, in which case the at least one evaluation unit can use the at least one known value as a fallback opportunity and thus be able to generate at least one valid value for the radiation temperature at any time.

[0044] Further according to the invention, the at least one radiation sensitive element is arranged such that the thermal radiation passes through the at least one transition material before being received by the at least one radiation sensitive element. As used herein, the term "transition material" refers to a material located in the optical path of the thermal radiation traversed by the thermal radiation before it irradiates the at least one radiation sensitive element. In particular, the at least one transition material can be selected from at least one ceramic material, in particular at least one ceramic material as typically used in ceramic glass countertops. In particular, the at least one transition material can have mechanical strength so that it can carry at least one cooking utensil. Furthermore, the at least one transition material can be thermally insensitive so that it can withstand repeated and / or rapid temperature changes. Furthermore, the at least one transition material can have a fairly low thermal conductivity so that it can remain at ambient temperature outside the cooking zone designated to receive the at least one cooking utensil. Furthermore, the at least one transition material may be at least partially transparent to thermal and optical radiation, but not transparent or "only partially transparent" to thermal and / or optical radiation in at least one further wavelength range, in particular a wavelength range selected from above 2.8 μm to 3.2 μm. As used herein, the term "partially transparent" refers to a transparency of the at least one transition material to thermal radiation of preferably 10% or less, more preferably 2% or less, particularly preferably 1% or less.

[0045] Preferably, the at least one ceramic material used in the present invention can be selected from the LAS system, where the term "LAS system" denotes a mixture of lithium oxide, silicon oxide, aluminum oxide, and at least one additional component, in particular at least one glass phase former, such as sodium oxide, potassium oxide, calcium oxide, refining agent and / or nucleating agent, such as a mixture of zirconium(IV) oxide and titanium(IV) oxide. A particular type of such material is known as CERAN®. However, further types of ceramic materials may be possible.

[0046] Further according to the invention, at least one of the at least one light source and the at least one radiation sensitive element is arranged such that the optical radiation passes through the at least one transition material and impinges on the at least one radiation emitting element before being received by the at least one radiation sensitive element. By way of example, the light source may be arranged and / or aligned such that it at least partially emits optical radiation towards the radiation emitting element from which the optical radiation may be at least partially reflected towards the radiation sensitive element. The radiation sensitive element may thus be positioned and / or aligned such that the radiation sensitive element receives optical radiation at least partially reflected from the radiation emitting element. Further options may also be possible.

[0047] Furthermore, the device according to the invention comprises at least one evaluation unit. As used herein, the term "evaluation unit" generally refers to any device designed to generate at least one piece of information based on measured data. More specifically, the evaluation unit according to the invention is designated for determining that the at least one evaluation unit is configured to determine the radiation temperature of the at least one radiation-emitting element by using at least values ​​of the intensity of thermal and optical radiation, the values ​​relating to the intensity of thermal and optical radiation being acquired by the at least one radiation-sensitive element and transferred to the evaluation unit. For this purpose, the evaluation unit may be or comprise one or more integrated circuits, such as one or more application specific integrated circuits (ASICs), and / or one or more digital signal processors (DSPs), and / or one or more field programmable gate arrays (FPGAs), and / or one or more data processing devices, for example one or more computers, preferably one or more microcomputers and / or microcontrollers. Additional components may be included, such as one or more devices for receiving and / or pre-processing the sensor signals, one or more pre-processing devices and / or data acquisition devices, for example one or more AD converters and / or one or more filters. Furthermore, the evaluation device may include one or more data storage devices. Furthermore, the evaluation device may include one or more interfaces, for example one or more wireless interfaces and / or one or more wired interfaces.

[0048] In a preferred embodiment, the at least one evaluation unit is further configured to determine the emissivity of the at least one radiation-emitting element. As used herein, the term "emissivity" relates to the effectiveness of the at least one radiation-emitting element to emit thermal radiation. More specifically, the emissivity refers to a material property of the at least one radiation-emitting element, which is determined by the intensity of the thermal radiation emitted by the at least one radiation-emitting element. Generally, the emissivity is indicated by a value between 0 and 1, a value of 1 corresponding to the surface of a perfect black body that emits thermal radiation according to Planck's law, and the emissivity of the at least one radiation-emitting element usually assumes a value less than 1 but greater than 0, typically greater than 0.5, more typically greater than 0.8, preferably greater than 0.9. In particular, the at least one evaluation unit may be configured to determine the emissivity of the at least one radiation-emitting element as a function of the at least one further sensor signal depending on the intensity of the optical radiation emitted by the at least one light source, the at least one further sensor signal being generated by the at least one radiation sensitive element. The optical properties, in particular the spectral properties, of the optical radiation can be determined in advance by using a light source. In particular, the light source can emit a known spectrum at least partially towards the radiation-emitting element. Thus, a variation of the optical radiation caused by the interaction with the radiation-emitting element can be determined. Such a variation can in particular be related to the emissivity of the radiation-emitting element. In other words, the determined variation of the optical radiation can in particular be related to the emissivity of the radiation-emitting element. Thus, the emissivity of the radiation-emitting element can be represented by a function of the further sensor signal. This function can in particular take into account the initial optical properties of the optical radiation emitted by the light source before interacting with the radiation-emitting element.

[0049] In a further preferred embodiment, the device according to the invention may further comprise at least one further radiation sensitive element, which may be designed to generate at least one further sensor signal depending on the intensity of the further thermal radiation emitted by the at least one transition material in at least one further wavelength range. More specifically, for the terms "further radiation sensitive element", "further sensor signal" or "further wavelength range", the definitions of the terms "radiation sensitive element", "sensor signal" or "wavelength range", respectively, may apply mutatis mutandis. In this further preferred embodiment, the at least one transition material may not be transparent at all or may only be partially transparent to the thermal radiation emitted by the radiation emitting element in at least one further wavelength range. For the term "partially transparent", see the definition above.

[0050] In a particularly preferred embodiment, the at least one wavelength range and / or the at least one further wavelength range may be selected from at least one wavelength from above 2.8 μm to 3.2 μm, in particular when at least one layer of at least one photoconductive material as comprised in at least one sensor area of ​​the at least one radiation sensitive element comprises lead sulfide (PbS), which is particularly sensitive in the wavelength range from 0.8 μm to 2.8 μm. In this particularly preferred embodiment, the at least one PbS comprising radiation sensitive element may be used to determine the intensity of thermal and / or optical radiation in at least one wavelength range selected from 0.8 μm to 2.8 μm and / or at least one further radiation sensitive element may be selected to be sensitive in the further wavelength range selected from wavelengths from above 2.8 μm to 3.2 μm, while the at least one PbS comprising radiation sensitive element is insensitive to incident thermal radiation and / or incident optical radiation having a wavelength in the further wavelength range.

[0051] In this further preferred embodiment, the at least one evaluation unit may further be configured to take into account at least one further sensor signal measured by the at least one further radiation sensitive element when determining the radiation temperature of the at least one radiation emitting element. For this purpose, the at least one evaluation unit may further be configured to correct the intensity of the thermal radiation and / or the optical radiation by removing the contribution of the intensity of the further thermal radiation possibly emitted by the at least one transition material from the intensity of the thermal radiation emitted by the at least one radiation emitting element and / or the optical radiation emitted by the at least one light source, respectively. In this way, more suitable results for the proportion of the thermal radiation only emitted by the at least one radiation emitting element and / or the optical radiation only emitted by the at least one light source can be obtained in a reproducible manner that can take into account the change in the contribution of the further thermal radiation that may be emitted by the at least one transition material.

[0052] In a further preferred embodiment, the device according to the invention may further comprise at least one temperature sensor, which may be designated to monitor the temperature of the at least one radiation sensitive element and / or the at least one transition material. As generally used, the term "temperature sensor" refers to any type of sensor designated to generate at least one sensor signal from which a temperature can be derived. In particular, the at least one temperature sensor may be selected from at least one of a thermoelectric sensor, a thermistor, a thermocouple, a resistance temperature detector (RTD), a semiconductor-based integrated circuit configured to determine at least one temperature by using at least one physical property of at least one transistor. However, further types of temperature sensors are also possible. Preferably, the at least one temperature sensor designated to monitor the temperature of the at least one radiation sensitive element may be arranged in at least one vicinity of the at least one radiation sensitive element. Further preferably, the at least one temperature sensor designated to monitor the temperature of the at least one transition material may be designed to monitor the temperature of a portion of the at least one transition material passed by an optical path between the at least one radiation emitting element and the at least one radiation sensitive element. Furthermore, the at least one evaluation unit may additionally be configured to take into account the temperature measured by the at least one temperature sensor when determining the radiation temperature of the at least one radiation-emitting element, in this way a contribution of the at least one radiation sensitive element and / or of the at least one transition material to the at least one sensor signal generated by the at least one radiation sensitive element can be taken into account and preferably removed from the at least one sensor signal generated by the at least one radiation sensitive element.

[0053] In a further preferred embodiment, the device according to the invention may further comprise at least one reference radiation sensitive element, the at least one reference radiation sensitive element having at least one covered sensor area. Preferably, the at least one covered sensor area may comprise the same photosensitive material as the at least one radiation sensitive element in order to facilitate a comparison of a reference signal generated by the at least one covered sensor area of ​​the at least one reference radiation sensitive element with a sensor signal generated by the at least one sensor area of ​​the at least one radiation sensitive element. As used herein, the term "covered" refers to a specific arrangement of the at least one reference radiation sensitive element that prevents the at least one reference radiation sensitive element from receiving thermal radiation emitted by the at least one radiation emitting element. For this purpose, the at least one covered sensor area may be covered by using a radiation absorbing layer, which may be designed to absorb thermal and / or optical radiation, and / or a radiation reflecting layer, which may be designed to reflect thermal and / or optical radiation. Furthermore, the at least one evaluation unit may additionally be configured to take into account the at least one reference signal in determining the radiation temperature of the at least one radiation emitting element. In this way, changes in the at least one radiation sensitive element over a period of time can be taken into account and preferably removed from the at least one sensor signal generated by the at least one radiation sensitive element.

[0054] In a further preferred embodiment, the device according to the invention may further comprise at least one presence sensor. As used herein, the term "presence sensor" refers to any type of sensor designated to generate at least one sensor signal from which information about the occupancy of the radiation path in front of at least one light-sensitive area in at least one predetermined range can be determined. The presence sensor may further be designated to generate at least one sensor signal from which a distance from the presence sensor can be derived. In particular, the at least one presence sensor may be selected from the group consisting of time-of-flight sensors, distance sensors, proximity sensors, ultrasonic sensors, optical sensors, inductive sensors, tactile sensors, radar sensors, triangulation sensors, stereo sensors, structured light sensors, capacitive sensors, FIP sensors, BPA sensors, as known to the skilled person. Here, the at least one presence sensor may be preferably configured to determine at least one further object that may be positioned such that the thermal radiation may pass through at least one further object before it can be received by the at least one radiation sensitive element, thus affecting the at least one sensor signal generated by the at least one radiation sensitive element. In particular, the at least one further object may not be transparent in at least one of the at least one wavelength range of the radiation-emitting element and the at least one further wavelength range of the optical radiation, thereby reducing the at least one sensor signal generated by the at least one radiation-sensitive element. More specifically, the at least one further object may be selected from a plastic container and / or a burn mark that may be placed on the ceramic glass countertop. The presence of the at least one further object can be taken into account by using at least one presence sensor and arranging the at least one presence sensor at a distance between the at least one presence sensor and a surface of the ceramic glass countertop that is easily accessible from outside the heating system. At least one notification, such as at least one warning, may be provided to a person using the heating system upon the occurrence of such an event, as will be described in more detail below.

[0055] In a further preferred embodiment, the device according to the invention may further comprise at least one thermoelectric cooler. The thermoelectric cooler may in particular be configured to cool at least one radiation sensitive element. As used herein, the term "thermoelectric cooler" refers to an electrically driven heat pump designated for transferring heat between at least two spatial regions, thereby generating a heat flux between the at least two spatial regions. The thermoelectric cooler may in particular be based on the Peltier effect for generating the heat flux. For this purpose, the thermoelectric cooler may in particular comprise at least one Peltier element. The direction of the heat flux may depend on the direction of the electric current applied to the thermoelectric cooler. Depending on the direction of the heat flux, the thermoelectric cooler may be used to cool at least one spatial region by transferring heat to at least one further spatial region or to heat at least one spatial region by transferring heat from at least one further spatial region. However, further types of thermoelectric coolers are also possible.

[0056] In a further preferred embodiment, the device according to the invention may further comprise at least one optical radiation shield. As used herein, the term "optical radiation shield" refers to an element configured to shield or cover an object from direct optical radiation. Thus, the optical radiation shield may at least partially cover an object such that the object cannot be directly irradiated. The optical radiation shield may in particular be configured to allow indirect optical radiation, such as reflected optical radiation, to impinge on the object. The optical radiation shield may comprise at least one solid material, such as a synthetic plastic material or a metal, that absorbs and / or reflects optical radiation. In particular, the optical radiation shield may be configured to prevent at least one radiation sensitive element from being directly irradiated by optical radiation emitted by the at least one light source. Additionally or alternatively, the optical radiation shield may be configured to prevent at least one further radiation sensitive element from being directly irradiated by optical radiation emitted by the at least one light source.

[0057] In a further aspect of the present invention, a heating system for heating at least one radiation-emitting element to emit thermal radiation at a radiation temperature is disclosed. According to the present invention, the heating system comprises: - at least one device for monitoring a radiation temperature of at least one radiation-emitting element, said at least one radiation-emitting element emitting thermal radiation at said radiation temperature; and - at least one transition material arranged such that thermal radiation and light radiation pass through the at least one transition material before being received by the at least one radiation sensitive element, the at least one transition material being at least partially transparent to the thermal radiation and light radiation; - at least one heating unit, said at least one heating unit being designated to heat said at least one radiation-emitting element via said at least one transition material; and at least one control unit, which is designed to control the power of the at least one heating unit on the basis of a radiation temperature of the at least one radiation-emitting element determined by a device for monitoring the radiation temperature of the at least one radiation-emitting element; and Equipped with.

[0058] As commonly used, the term "system" refers to a plurality of spatial entities including at least the components listed above, where each listed component may be a separate component, but where two or more, but not all, of the components may be integrated into a common component, where the heating system comprises a device for monitoring the radiation temperature of at least one radiation-emitting element, as described in more detail above and below. In particular, the heating system may be or include at least one electric cooktop or induction cooktop for use in a domestic, canteen kitchen, or industrial kitchen, where the at least one radiation-emitting element may be selected from at least one cooking appliance, and where the at least one transition material may be selected from at least one ceramic material used in ceramic glass cooktops. However, further types of heating systems are also possible, in particular laboratory heating systems or industrial heating machines for hardening, tempering, brazing, welding, annealing, preheating, postheating, shrink fitting, bolt heating, forging and / or melting. Additionally, another type of heating system may be used in semiconductor wafer manufacturing and similar applications where the radiation sensitive element needs to be separated from the heating unit by a transition material to protect the radiation sensitive element and its electronics from harsh environmental conditions such as high temperatures, vacuum, corrosive gases, etc.

[0059] As used herein, the term "heating" or grammatical variations thereof refers to a process of increasing the temperature of at least one object, in particular at least one radiation-emitting element, preferably at least one cooking utensil. As further used herein, the term "heating unit" refers to any entity designated for heating at least one radiation-emitting element, preferably at least one cooking utensil, through at least one transition material, preferably at least one ceramic material, such as those used in ceramic glass countertops. In a particularly preferred embodiment, the at least one heating unit may comprise at least one heating element having at least one opening, which is preferably designated such that the thermal radiation emitted by the at least one radiation-emitting element and the light radiation emitted by the at least one light source can pass through the at least one opening to impinge on at least one sensor area of ​​the at least one radiation-sensitive element. Preferably, the at least one heating element may be or include at least one induction coil and / or at least one infrared halogen lamp; however, further types of heating elements may also be possible. Here, the at least one induction coil may be designed to heat at least one radiation emitting element, preferably at least one cooking utensil, by using thermal and / or electromagnetic induction.

[0060] In a particularly preferred embodiment, the heating system may further comprise at least one thermal shield. As used herein, the term "thermal shield" refers to any entity designated to keep at least one heating unit, in particular the thermal radiation generated by at least one heating element, from impinging on at least one radiation-emitting element, in particular the device for monitoring the radiation temperature of the radiation-sensitive element. For this purpose, the thermal shield may preferably be designed to shield at least one radiation-emitting element, in particular the at least one device for monitoring the radiation temperature of the at least one radiation-sensitive element, from the at least one heating unit. Preferably, the at least one thermal shield may include at least one opening, which may be designated so that the thermal radiation emitted by the at least one radiation-emitting element and the light radiation emitted by the at least one light source pass through the at least one opening. In this way, the thermal radiation emitted by the at least one radiation-emitting element may travel along an optical path to the at least one radiation-sensitive element, thereby avoiding a part of the thermal radiation being absorbed by the thermal shield body.

[0061] As further used herein, the term "control unit" refers to any entity designated to control the output of at least one heating unit. According to the invention, the at least one control unit is configured to control the output of at least one heating unit based on the radiation temperature of at least one radiation-emitting element determined by using a device for monitoring the radiation temperature of at least one radiation-emitting element. In this way, the radiation temperature of at least one radiation-emitting element, in particular at least one cooking appliance, can be adjusted to a predefined value, preferably in an automatic manner.

[0062] In addition, the heating system may further comprise at least one setting element. As used herein, the term "setting element" refers to any entity configured to receive at least one information input by at least one user of the heating system. In this way, at least one user of the heating may set the radiation temperature of at least one radiation-emitting element, in particular at least one cooking utensil, to a desired value. In a preferred embodiment, the desired value may preferably overwrite a predefined value, or vice versa, to be adjusted in an automatic manner by using at least one control unit. However, further varieties of adjusting the radiation temperature of the at least one radiation-emitting element, in particular at least one cooking utensil, may also be possible, whereby one or both of the desired value and the predefined value may be taken into account, in particular depending on a preselected procedure.

[0063] Furthermore, the heating system may further comprise at least one notification unit. As generally used, the term "notification unit" refers to any entity configured to provide at least one further piece of information, preferably visually, acoustically or tactilely, to at least one user of the heating system. In particular, the at least one notification unit may provide at least one piece of information on at least one of the following: - the actual value of the radiation temperature of at least one radiation-emitting element, in particular at least one cooking utensil, determined by using the device described herein; - at least one desired value for the radiation temperature; - at least one predefined value for the radiation temperature; at least one notification, preferably upon the occurrence of at least one event, in particular o The presence of at least one further object, such as a plastic container or burn marks, which may assume, accidentally or intentionally, the position of at least one cooking utensil on the countertop and which may pose a potential fire hazard on the countertop; o An unexpected, rapid change in the radiation temperature, indicating complete evaporation of the contents of at least one radiation-emitting element, in particular at least one cooking utensil, which may lead to overheating; a sudden change in the emission value of at least one radiation-emitting element, in particular at least one cooking utensil, which may indicate an overflow; at least one notification, which is at least one warning selected from: and / or the occurrence of at least one event prevents operation of the countertop; to a user of the heating system.

[0064] Preferably, the at least one heating system may be arranged such that the at least one transition material can comprise at least one cooking zone, preferably two, three, four, five, six or more individual cooking zones, which can preferably be controlled independently with respect to each other. In a particularly preferred embodiment, a separate heating unit, a separate setting element and a separate device for monitoring the radiation temperature of at least one radiation-emitting element, which emits thermal radiation at a radiation temperature, may preferably be provided for each cooking zone, and at least one control unit and at least one notification unit, respectively, may be provided as a single unit for all cooking zones. Alternatively, in a preferred embodiment, at least one optical element may be used, which at least one optical element may be designated to direct the thermal radiation received from at least two individual cooking zones to a single device for monitoring the radiation temperature of at least one radiation-emitting element configured for such purpose, in particular by being configured to apply a multiplexing procedure for monitoring the radiation temperature of at least two radiation-emitting elements, which may be arranged in at least two individual cooking zones. However, further configurations are also possible.

[0065] For further details regarding the heating system, reference may be made to the device for monitoring the radiation temperature of at least one radiation-emitting element described above or in more detail below.

[0066] In a further aspect of the present invention, a method for monitoring a radiation temperature of at least one radiation-emitting element, the at least one radiation-emitting element emitting thermal radiation at a radiation temperature, is disclosed. The method comprises the following steps, which may preferably be performed in a predetermined order, where the steps may be performed overlapping in time. Furthermore, the method may comprise further steps, whether or not they may be described herein. Thus, the method comprises the following steps: - generating at least one sensor signal by using at least one radiation sensitive element, the at least one radiation sensitive element having at least one sensor area, the at least one sensor area comprising a photosensitive material selected from photoconductive materials, the at least one sensor area being designated to generate at least one sensor signal in response to an intensity of thermal radiation, within at least one wavelength range, emitted by at least one radiation emitting element and received by the sensor area, the at least one radiation sensitive element being arranged such that the thermal radiation passes through at least one transition material before being received by the at least one radiation sensitive element; - emitting optical radiation at least partially towards at least one radiation-emitting element by using at least one light source; - generating at least one further sensor signal by using at least one radiation sensitive element, the sensor area being configured to generate the at least one further sensor signal depending on the intensity of optical radiation emitted by at least one light source in at least one further wavelength range and received by the sensor area; - determining a radiation temperature of the at least one radiation-emitting element by evaluating the sensor signal of the at least one radiation sensitive element by using at least one evaluation unit, the at least one evaluation unit being configured to determine the radiation temperature of the at least one radiation-emitting element by using intensity values ​​of thermal radiation and of light radiation; Includes.

[0067] Preferably, the method further comprises the steps of: - generating at least one further sensor signal as a function of the intensity of further thermal radiation emitted by at least one transition material in at least one wavelength range, the at least one transition material being non-transparent or only partially transparent to the thermal radiation emitted by the radiation-emitting element in the at least one further wavelength range; - determining a radiation temperature of the at least one radiation-emitting element by taking into account the at least one further sensor signal when determining the radiation temperature of the at least one radiation-emitting element; - generating at least one reference signal by using at least one reference radiation sensitive element, the at least one reference radiation sensitive element having at least one covered sensor area, the at least one covered sensor area comprising the same light sensitive material as the at least one radiation sensitive element and being covered in a manner that prevents the reference radiation sensitive element from receiving the thermal radiation emitted by the at least one radiation emitting element; - determining the radiation temperature of the at least one radiation-emitting element taking into account the at least one reference signal when determining the radiation temperature of the at least one radiation-emitting element; - determining the emissivity of at least one material comprised in said at least one radiation-emitting element by using the radiation temperature of said at least one radiation-emitting element; It may include at least one of the following.

[0068] In a further aspect of the present invention, a method for heating at least one radiation-emitting element to emit thermal radiation at a radiation temperature is disclosed. The method comprises the following steps, which may be preferably performed in a predetermined order, where the steps may be performed overlapping in time. Furthermore, the method may comprise further steps, whether or not they may be described herein. Thus, the method comprises the following steps: - monitoring a radiation temperature of at least one radiation-emitting element by a method for monitoring a radiation temperature of at least one radiation-emitting element as described elsewhere herein, said at least one radiation-emitting element emitting thermal radiation at said radiation temperature; - controlling the output of at least one heating unit based on the radiation temperature of at least one radiation-emitting element determined by the method of monitoring the radiation temperature of at least one radiation-emitting element according to any one of the embodiments of the method, the at least one heating unit being designated to heat the at least one radiation-emitting element via at least one transition material, the at least one transition material being arranged such that the thermal and optical radiation pass through the at least one transition material before being received by the at least one radiation sensitive element; Includes.

[0069] In a particularly preferred embodiment, controlling the output of the at least one heating unit may further comprise determining the presence of at least one further object apart from the at least one radiation-emitting element by using the emissivity of the at least one radiation-emitting element. As described in more detail above or below, the at least one radiation-emitting element may preferably be selected from at least one cookware, while the at least one further object may in particular be selected from at least one of a plastic container or a burn mark located on a ceramic glass countertop.

[0070] In a particularly preferred embodiment, the control of the output of the at least one heating unit may further comprise determining the presence of a boil-dry condition in the at least one radiation-emitting element after the aqueous liquid, such as water, has completely evaporated. For this purpose, the time course of the radiation temperature of the at least one radiation-emitting element, in particular the at least one cooking utensil, can be used. It is generally known that the radiation temperature of the at least one cooking utensil rises rapidly after the aqueous liquid has completely evaporated. Based on the detection of the rate at which the temperature of the at least one cooking utensil rises, it is possible to determine the presence of a boil-dry condition in the at least one cooking utensil. Furthermore, the operation of the at least one heating unit can be prevented after the presence of a boil-dry condition in the at least one radiation-emitting element, in particular the at least one cooking utensil, has been confirmed. Alternatively or additionally, at least one notification, such as at least one warning, can preferably be provided to at least one user of the heating device.

[0071] For further details regarding the methods used herein, please refer to the corresponding devices or systems described above or below.

[0072] The device and method according to the invention offer various advantages with respect to devices and methods known from the prior art: the device and method make it possible to simply and easily monitor the temperature of at least one object emitting thermal radiation, in particular the temperature of at least one cookware, in particular a ceramic glass countertop, through at least one transition material, in particular a ceramic glass countertop, preferably arranged such that the thermal radiation travels through the at least one transition material before being received by the at least one radiation sensitive element, without the need to know the emissivity of the at least one object.

[0073] The spectral sensitivity range and high detection rate of PbS-based radiation sensitive elements in the wavelength range of interest may allow the measurement of radiation temperature without the need for optical materials with high transmittance such as transparent quartz windows. Such windows would require drilling holes in the transition material, especially CERAN, which could reduce the mechanical integrity of the heating system. Other detector technologies such as pyroelectric detectors, thermopiles, and bolometers have very low sensitivity in the same wavelength range, so a transparent window is required. Highly sensitive detector technologies such as InGaAs cannot cover wavelength ranges beyond 2 μm.

[0074] The contribution of the transition material, in particular CERAN®, can be taken into account by measuring the radiation by using a further radiation sensitive element in a third wavelength range or by measuring the temperature of the transition material using a temperature sensor and calculating the contributions in the first and second wavelength ranges. In this way, temperature measurements through the transition material, in particular CERAN®, are possible. Long-term and temperature drifts of the detector and electronics can be taken into account using a reference radiation sensitive element.

[0075] By sampling the emission spectrum of the radiation-emitting element at at least two different wavelengths, the material dependence of the measurement due to different values ​​of emissivity can be eliminated. The emissivity or emissivity-dependent parameters of the radiation-emitting element, in particular of the cookware, can be determined, so that sudden changes in emissivity can be detected and fire hazards due to boiling of liquids, such as milk, can be prevented.

[0076] Compared to the above detector technologies, PbS detectors are much faster. Since the radiation temperature of the radiation-emitting element can be continuously monitored using the method of the present invention, a sudden change in the radiation temperature of the radiation-emitting element can be detected, which can indicate the complete evaporation of the contents in the radiation-emitting element, for example, during cooking and boiling. In particular, empty frying pans and pots can reach high temperatures very quickly, which can lead to overheating and cause scorching of the coating. High temperatures can further cause gas generation from the surface of the radiation-emitting element. Furthermore, it can cause warping and / or denting of the radiation-emitting element.

[0077] Further advantages are set forth throughout this specification.

[0078] As used herein, the terms "having", "comprises" or "including", or any grammatical variants thereof, are used in a non-exclusive manner. Thus, these terms may refer both to the situation where, apart from the features introduced by these terms, no further features are present in the entity described in this context, and to the situation where one or more further features are present. As an example, the expressions "A has B", "A comprises B" and "A includes B" may refer both to the situation where no other elements are present in A apart from B (i.e., A is solely and exclusively composed of B), and to the situation where, in addition to B, one or more further elements are present in the entity A, such as element C, elements C and D, or further elements.

[0079] Furthermore, as used herein, the terms "preferably", "more preferably", "particularly", "more particularly", "particularly", "more particularly" or similar terms are used in connection with any feature without limiting the possibility of substitution. Thus, features introduced by these terms are optional features and are not intended to limit the scope of the claims in any way. The invention can be implemented by using alternative features, as the skilled person will recognize. Similarly, features introduced by "in one embodiment of the invention" or similar expressions are intended to be optional features, without any limitation on alternative embodiments of the invention, without any limitation on the scope of the invention, and without any limitation on the possibility of combining the feature introduced in such a way with other optional or non-optional features of the invention.

[0080] In summary, the following embodiments are preferred in the present invention: Embodiment 1: An apparatus for monitoring a radiation temperature of at least one radiation-emitting element, the at least one radiation-emitting element emitting thermal radiation at a radiation temperature, the apparatus comprising: - at least one light source, said light source configured to emit optical radiation at least partially towards said at least one radiation-emitting element; at least one radiation sensitive element, said at least one radiation sensitive element having at least one sensor area, said at least one sensor area comprising at least one photosensitive material selected from at least one photoconductive material, said at least one sensor area being designated to generate at least one sensor signal in dependence on the intensity of thermal radiation emitted by at least one radiation emitting element and received by said sensor area within at least one wavelength range, said sensor area being adapted to generate at least one sensor signal in dependence on the intensity of thermal radiation emitted by at least one light source and received by said sensor area within at least one further wavelength range; at least one of the at least one light source and the at least one radiation sensitive element, further configured to generate at least one further sensor signal in response to an intensity of the optical radiation emitted by the at least one radiation sensitive element, the at least one radiation sensitive element being arranged such that the thermal radiation passes through at least one transition material before being received by the at least one radiation sensitive element, and the at least one of the at least one light source and the at least one radiation sensitive element being arranged such that the optical radiation passes through at least one transition material and impinges on at least one radiation emitting element before being received by the at least one radiation sensitive element; at least one evaluation unit, which is configured to determine a radiation temperature of the at least one radiation-emitting element by using the intensity values ​​of the thermal radiation and the light radiation; and An apparatus comprising:

[0081] Embodiment 2: The apparatus of the preceding embodiment, wherein the at least one light source is or includes an incandescent lamp or a thermal infrared emitter, and the thermal infrared emitter is a micromachined thermal radiation device having a radiation emitting surface as a radiation emitting element.

[0082] Embodiment 3: An apparatus according to any one of the preceding embodiments, wherein the at least one photoconductive material comprises lead sulfide and the at least one wavelength range and / or the at least one further wavelength range is selected from wavelengths between 0.8 μm and 2.8 μm.

[0083] Embodiment 4: A device according to any one of the preceding embodiments, wherein the at least one photoconductive material comprises lead selenide and the at least one wavelength range and / or the at least one further wavelength range is selected from wavelengths between 0.8 μm and 5 μm.

[0084] Embodiment 5: An apparatus according to any one of the preceding embodiments, wherein at least one wavelength range of the thermal radiation is at least partially, preferably completely, encompassed by at least one further wavelength range of the optical radiation, or at least one further wavelength range of the optical radiation is at least partially, preferably completely, encompassed by at least one wavelength range of the thermal radiation.

[0085] Embodiment 6: An apparatus according to any one of the preceding embodiments, wherein the at least one further wavelength range of the optical radiation is identical to the at least one wavelength range of the thermal radiation.

[0086] Embodiment 7: The apparatus of any one of the preceding embodiments, wherein the at least one transition material is selected from at least one ceramic material used in ceramic glass countertops.

[0087] Embodiment 8: An apparatus described in any one of the preceding embodiments, wherein the at least one evaluation unit is further configured to determine an emissivity of at least one radiation emitting element, the emissivity relating to the effectiveness of the at least one radiation emitting element to emit the thermal radiation.

[0088] Embodiment 9: An apparatus as described in the preceding embodiment, wherein the at least one evaluation unit is configured to determine the emissivity of the at least one radiation emitting element as a function of the at least one further sensor signal in response to the intensity of the optical radiation emitted by the at least one light source.

[0089] Embodiment 10: at least one further radiation sensitive element, which is designated for generating at least one further sensor signal dependent on an intensity of a further thermal radiation emitted by the at least one transition material in at least one further wavelength range, and which is not transparent or is only partially transparent to the thermal radiation emitted by the radiation emitting element in the at least one further wavelength range of the further thermal radiation, 13. The apparatus of any one of the preceding embodiments, further comprising:

[0090] Embodiment 11: The device described in the preceding embodiment, wherein the at least one evaluation unit is further configured to take into account the at least one further sensor signal measured by the at least one further radiation sensitive element when determining the radiation temperature of the at least one radiation emitting element.

[0091] Embodiment 12: The apparatus described in the preceding embodiment, wherein the at least one evaluation unit is further configured to correct the intensity of the thermal radiation by removing from the intensity of the thermal radiation emitted by the at least one radiation emitting element a contribution of the intensity of further thermal radiation that may be emitted by the at least one transition material.

[0092] Embodiment 13: A device described in any one of the preceding three embodiments, wherein the at least one further wavelength range is selected from at least one wavelength greater than 2.8 μm to 3.2 μm.

[0093] Embodiment 14: at least one temperature sensor, said at least one temperature sensor comprising: said at least one radiation sensitive element; or said at least one transition material, is specified to monitor the temperature of at least one of the at least one evaluation unit further comprises at least one temperature sensor, the evaluation unit being further configured to take into account a temperature measured by the at least one temperature sensor when determining a radiation temperature of the at least one radiation-emitting element. 13. The apparatus of any one of the preceding embodiments.

[0094] Embodiment 15: An apparatus as described in the preceding embodiment, wherein the at least one temperature sensor is designated to monitor the temperature of a portion of the at least one transition material passed by an optical path between the at least one radiation emitting element and the at least one radiation sensitive element.

[0095] Embodiment 16: at least one reference radiation sensitive element, the at least one reference radiation sensitive element having at least one covered sensor area, the at least one covered sensor area comprising the same light sensitive material as the at least one radiation sensitive element, the at least one covered sensor area being covered so as to prevent the reference radiation sensitive element from receiving thermal radiation emitted by the at least one radiation emitting element, the at least one covered sensor area being designated to generate at least one reference signal; 13. An apparatus according to any one of the preceding embodiments, wherein the at least one evaluation unit is further configured to take into account at least one reference signal when determining the radiation temperature of the at least one radiation-emitting element.

[0096] Embodiment 17: The at least one covered sensor area comprises: - a radiation absorbing layer designed to absorb said thermal and optical radiation; or a radiation reflective layer designed to reflect said thermal and optical radiation, The device according to any preceding embodiment, covered by at least one of the following:

[0097] Embodiment 18: at least one presence sensor configured to determine at least one further object arranged such that the thermal radiation passes through the at least one further object before it can be received by the at least one radiation sensitive element; 13. The apparatus of any one of the preceding embodiments, further comprising:

[0098] Embodiment 19: An apparatus as described in the preceding embodiment, wherein the at least one further object is not transparent or partially transparent in at least one of the at least one wavelength range of the thermal radiation emitted by the at least one radiation emitting element and the at least one further wavelength range of the optical radiation emitted by the at least one light source.

[0099] Embodiment 20: An apparatus according to any one of the preceding two embodiments, wherein the at least one further object is selected from at least one of a plastic container and / or a burn mark placed on a ceramic glass countertop.

[0100] Embodiment 21: An apparatus described in any one of the preceding three embodiments, wherein the at least one presence sensor is selected from at least one of a time-of-flight sensor, a distance sensor, a proximity sensor, an ultrasonic sensor, an optical sensor, an induction sensor, a tactile sensor, a radar sensor, a triangulation sensor, a stereo sensor, a structured light sensor, a capacitance sensor, a FIP sensor, and a BPA sensor.

[0101] Embodiment 22: - at least one thermoelectric cooler configured to cool said at least one radiation sensitive element; 13. The apparatus of any one of the preceding embodiments, further comprising:

[0102] Embodiment 23: at least one optical radiation shield, said optical radiation shield being configured to shield the at least one radiation sensitive element, and optionally the at least one further radiation sensitive element, from direct illumination by optical radiation emitted by the at least one light source; 13. The apparatus of any one of the preceding embodiments, further comprising:

[0103] Embodiment 24: A heating system for heating at least one radiation-emitting element to emit thermal radiation at a radiation temperature, the system comprising: - at least one device for monitoring a radiation temperature of at least one radiation-emitting element according to any one of the preceding embodiments, wherein the at least one radiation-emitting element emits thermal radiation at the radiation temperature; and - at least one transition material arranged such that thermal radiation and optical radiation pass through the at least one transition material before being received by the at least one radiation sensitive element, the at least one transition material being at least partially transparent to the thermal radiation and optical radiation; - at least one heating unit, said at least one heating unit being designated to heat said at least one radiation-emitting element via said at least one transition material; and at least one control unit, which is designed to control the power of the at least one heating unit on the basis of a radiation temperature of the at least one radiation-emitting element determined by a device for monitoring the radiation temperature of the at least one radiation-emitting element; and A system comprising:

[0104] Embodiment 25: A system described in the preceding embodiment, wherein the at least one heating unit comprises at least one heating element having at least one opening designated so that the thermal radiation emitted by the at least one radiation emitting element and the light radiation emitted by the at least one light source pass through the at least one opening.

[0105] Embodiment 26: The system described in the preceding embodiment, wherein the at least one heating element is selected from at least one of an induction coil or at least one infrared halogen lamp, and the at least one induction coil is designed to heat the at least one radiation-emitting element by using at least one of heat or electromagnetic induction.

[0106] Embodiment 27: at least one thermal shield, which is designated to shield at least one device for monitoring a radiant temperature of the at least one radiation-emitting element from the at least one heating unit, the at least one thermal shield comprising at least one opening designated to allow the thermal radiation emitted by the at least one radiation-emitting element and the optical radiation emitted by the at least one optical source to pass through the at least one opening; 13. The system of any one of the preceding embodiments, further comprising:

[0107] Embodiment 28: at least one setting element configured to receive at least one piece of information input by at least one user of the heating system; or - at least one notification unit configured to provide at least one further information to at least one user of said heating system; 13. The system of any one of the preceding embodiments, further comprising at least one of:

[0108] Embodiment 29: - said at least one radiation-emitting element is selected from at least one cooking utensil; - said at least one transition material is selected from at least one ceramic material used in ceramic glass countertops; 13. The system of any one of the preceding embodiments.

[0109] Embodiment 30: A method for monitoring a radiation temperature of at least one radiation-emitting element, the at least one radiation-emitting element emitting thermal radiation at a radiation temperature, the method comprising the steps of: - generating at least one sensor signal by using at least one radiation sensitive element, the at least one radiation sensitive element having at least one sensor area, the at least one sensor area comprising a photosensitive material selected from photoconductive materials, the at least one sensor area being designated to generate at least one sensor signal in response to an intensity of thermal radiation within at least one wavelength range, emitted by at least one radiation emitting element and received by the sensor area, the at least one radiation sensitive element being arranged such that the thermal radiation passes through at least one transition material before being received by the at least one radiation sensitive element, the at least one transition material being at least partially transparent to the thermal radiation within at least one wavelength range; - emitting optical radiation at least partially towards at least one radiation-emitting element by using at least one light source; - generating at least one further sensor signal by using at least one radiation sensitive element, the sensor area being configured to generate the at least one further sensor signal depending on the intensity of optical radiation emitted by at least one light source in at least one further wavelength range and received by the sensor area; - determining a radiation temperature of the at least one radiation-emitting element by evaluating the sensor signal of the at least one radiation sensitive element by using at least one evaluation unit, the at least one evaluation unit being configured to determine the radiation temperature of the at least one radiation-emitting element by using intensity values ​​of thermal radiation and of light radiation; A method comprising:

[0110] Embodiment 31: The method according to the preceding embodiment, wherein determining the radiation temperature of the at least one radiation-emitting element includes using a single radiation-sensitive element.

[0111] Embodiment 32: - generating at least one further sensor signal as a function of the intensity of further thermal radiation emitted by the at least one transition material in at least one wavelength range, the at least one transition material being non-transparent or only partially transparent to the thermal radiation emitted by the radiation-emitting element in the at least one further wavelength range of the further thermal radiation; - determining a radiation temperature of the at least one radiation-emitting element by taking into account the at least one further sensor signal when determining the radiation temperature of the at least one radiation-emitting element; 13. The method of any one of the preceding embodiments, further comprising:

[0112] Embodiment 33: The method of the preceding embodiment, wherein determining the radiation temperature of the at least one radiation-emitting element includes correcting the intensity of the thermal radiation by removing from the intensity of the thermal radiation emitted by the at least one radiation-emitting element a contribution of the intensity of further thermal radiation emitted by the at least one transition material.

[0113] Embodiment 34: - monitoring the temperature of at least one of the following: said at least one radiation sensitive element; or said at least one transition material, and - determining a radiation temperature of at least one radiation-emitting element by taking into account the monitored temperature when determining the radiation temperature of the at least one radiation-emitting element; The method of any one of the preceding method embodiments, further comprising:

[0114] Embodiment 35: - generating at least one reference signal by using at least one reference radiation sensitive element, the at least one reference radiation sensitive element having at least one covered sensor area, the at least one covered sensor area comprising the same light sensitive material as the at least one radiation sensitive element, and being covered so as to prevent the reference radiation sensitive element from receiving optical radiation emitted by the at least one radiation emitting element and by the at least one light source; - determining a radiation temperature of the at least one radiation-emitting element taking into account the at least one reference signal when determining the radiation temperature of the at least one radiation-emitting element; The method of any one of the preceding method embodiments, further comprising:

[0115] Embodiment 36: - determining the emissivity of at least one material comprised in said at least one radiation-emitting element by using the radiation temperature of said at least one radiation-emitting element; The method of any one of the preceding method embodiments, further comprising:

[0116] Embodiment 37: The method according to the present invention comprises the steps of: - measuring at least one sensor signal in response to thermal radiation emitted by the radiation-emitting element; - measuring a temperature drift and correcting said at least one sensor signal for said temperature drift; - further correcting at least one sensor signal for at least one transition material through which the thermal radiation passes before being received by the at least one radiation sensitive element; - measuring at least one further sensor signal for the optical radiation emitted by the at least one optical source; - measuring a temperature drift and correcting said at least one further sensor signal for said temperature drift; - further correcting at least one further sensor signal for at least one transition material through which the optical radiation passes before said optical radiation is received by the at least one radiation sensitive element; - determining the emissivity of at least one radiation emitting element as a function of said at least one further sensor signal as a function of the intensity of the optical radiation; - determining a radiation temperature of the at least one radiation-emitting element by using the emissivity of the at least one radiation-emitting element; The method according to any one of the preceding method embodiments, comprising:

[0117] Embodiment 38: A method of heating at least one radiation-emitting element to emit thermal radiation at a radiation temperature, the method comprising the steps of: - monitoring a radiation temperature of at least one radiation-emitting element according to any one of the embodiments of the preceding method, said at least one radiation-emitting element emitting thermal radiation at said radiation temperature; - controlling the output of at least one heating unit based on a radiation temperature of at least one radiation-emitting element determined by a method for monitoring the radiation temperature of at least one radiation-emitting element according to any one of the preceding method embodiments, the at least one heating unit being designated to heat the at least one radiation-emitting element via at least one transition material, the at least one transition material being arranged such that the thermal and optical radiation passes through the at least one transition material before being received by at least one radiation sensitive element; A method comprising:

[0118]

[0041] Embodiment 39: Controlling the output of the at least one heating unit comprises: - by using the emissivity of the at least one radiation-emitting element, at least one further object separate from the at least one radiation-emitting element; or - a boil-dry state of the at least one radiation-emitting element after the aqueous liquid has completely evaporated, by using the time course of the radiation temperature of the at least one radiation-emitting element; To determine the existence of; And, the method of the preceding embodiment, further comprising preventing operation of the at least one heating unit after presence is confirmed.

[0119] Embodiment 40: - said at least one radiation-emitting element is selected from at least one cooking utensil; - the at least one further object is selected from at least one of a plastic container or a burn mark located on a ceramic glass countertop, 13. The method according to any preceding embodiment. [Brief description of the drawings]

[0120] Further optional details and features of the invention are evident from the description of preferred exemplary embodiments, which are described in conjunction with the dependent embodiments. In this context, certain features may be implemented alone or in any reasonable combination. The invention is not limited to the exemplary embodiments. The exemplary embodiments are illustrated diagrammatically in the figures. Identical reference numbers in the individual figures refer to identical elements, elements with identical functions or elements which correspond to each other in terms of functionality. In the figures: [Figure 1] FIG. 1 shows a schematic representation of a preferred embodiment of a heating system comprising a device for monitoring the radiation temperature of at least one radiation-emitting element according to the invention. [Diagram 2] FIG. 2 shows a schematic diagram of a further preferred embodiment of a heating system comprising a device for monitoring the radiation temperature of at least one radiation-emitting element according to the invention. [Diagram 3] 1 shows experimental data obtained by measurements carried out on a preferred embodiment of a heating system according to the invention; [Figure 4] FIG. 2 shows a schematic representation of a preferred embodiment of a method for heating at least one radiation-emitting element to a radiation temperature including a method for monitoring the radiation temperature of at least one radiation-emitting element according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0121] Exemplary embodiments FIG. 1 very diagrammatically illustrates an exemplary embodiment of a heating system 110 comprising at least one device 112 for monitoring the radiation temperature of at least one radiation-emitting element 114 according to the present invention. The heating system 110 further comprises at least one transition material 116, at least one heating unit 118 for heating the radiation-emitting element 114 via the transition material 116, and at least one control unit 120. The heating system 110 is thus configured to heat the at least one radiation-emitting element 114 to emit thermal radiation at a radiation temperature. As shown in FIG. 1, the radiation-emitting element 114 may specifically be a part of a cooking utensil 122, such as a pot or frying pan, although further cooking utensils 122 are also possible. In particular, at least a partition of the radiation-emitting element 114 may emit a major portion of the thermal radiation, and the partition may be selected from the bottom 124 of the radiation-emitting element 114, more specifically, which is arranged adjacent to the at least one transition material 116.

[0122] The device 112 comprises at least one light source 125, which may in particular be selected from an incandescent lamp 127 or a thermal infrared emitter 129. The light source 125 is configured to emit optical radiation at least partially towards the at least one radiation-emitting element 114. The device 112 comprises at least one radiation-sensitive element 126. The radiation-sensitive element 126 has at least one sensor area 128. The sensor area 128 comprises at least one photosensitive material selected from at least one photoconductive material. The sensor area 128 is designed to generate at least one sensor signal in response to the intensity of the thermal radiation emitted by the at least one radiation-emitting element 114 and received by said sensor area 128 in at least two distinct wavelength ranges. The sensor area 128 is further designed to generate at least one further sensor signal in response to the intensity of the optical radiation emitted by the at least one light source 125 and received by the sensor area 128 in at least one further wavelength range. The radiation sensitive elements 126 are positioned such that the thermal radiation passes through the at least one transition material 116 before being received by the at least one radiation sensitive element 126. The at least one light source 125 and at least one of the at least one radiation sensitive element 126 are positioned such that the optical radiation passes through the at least one transition material 116 and impinges on the at least one radiation emitting element 114 before being received by the at least one radiation sensitive element 126. The transition material 116 is at least partially transparent to thermal radiation in two distinct wavelength ranges. The transition material 116 may be selected from at least one ceramic material 130 such as those typically used in ceramic glass countertops.

[0123] The device 112 further comprises at least one evaluation unit 138. The evaluation unit 138 is configured to determine a radiation temperature of the at least one radiation emitting element 114 by using the values ​​of the intensities of the thermal radiation and the optical radiation. The evaluation unit 138 may further be configured to determine an emissivity of the at least one radiation emitting element 114. The emissivity may be related to the effectiveness of the at least one radiation emitting element 114 for emitting thermal radiation. In particular, the at least one evaluation unit 138 may be configured to determine the emissivity of the at least one radiation emitting element 114 as a function of the at least one further sensor signal, depending on the intensity of the optical radiation emitted by the at least one light source, generated by the at least one radiation sensitive element 126. The optical characteristics, in particular the spectral characteristics, of the optical radiation can be pre-determined by using the light source 125. In particular, the light source 125 can at least partially emit a known spectrum towards the radiation emitting element 114. Thus, a change in the optical radiation caused by the interaction with the radiation emitting element 114 can be determined. Such a variation may be specifically related to the emissivity of the radiation-emitting element 114. In other words, the determined variation of the optical radiation may be specifically related to the emissivity of the radiation-emitting element 114. The emissivity of the radiation-emitting element can therefore be represented by a function of the further sensor signal. This function may specifically take into account the initial optical properties of the optical radiation emitted by the light source 125 before interacting with the radiation-emitting element 114. The evaluation device 138 may be specifically connected to the radiation sensitive element 126 and / or the light source 125. The connection between the evaluation device 138 and the radiation sensitive element 126 and / or the light source 125 may be wired and / or wireless.

[0124] As already indicated above, the heating system 110 further comprises at least one control unit 120. The control unit 120 is designated to control the output of the at least one heating unit 118 based on the radiation temperature of the at least one radiation-emitting element 114 determined by the device 112 for monitoring the radiation temperature of the at least one radiation-emitting element 114. The heating unit 118 may comprise at least one heating element 140 having at least one opening 142 designated for the thermal radiation emitted by the at least one radiation-emitting element 114 to pass through the at least one opening 142. As shown diagrammatically in FIG. 1, the heating unit 118 may include an induction coil 144 having a hole in a central area of ​​the induction coil 144. The induction coil 144 may be designed to heat the at least one radiation-emitting element 114 by using at least one of heat or electromagnetic induction. Additionally or alternatively, the heating element 140 may comprise at least one infrared halogen lamp (not shown here).

[0125] The heating system 110 may further include at least one thermal shield 146. The thermal shield 146 may be designated to shield the at least one device 112 for monitoring the radiation temperature of the at least one radiation-emitting element 114 from the at least one heating unit 118. As shown in FIG. 1 , the thermal shield 146 may include at least one opening 148 designated to allow thermal radiation emitted by the at least one radiation-emitting element 114 to pass through the at least one opening 148.

[0126] The heating system 110 may further comprise at least one setting element 150. The setting element 150 may be configured to receive at least one information that may be input by at least one user of the heating system 110. As an example, a user may set the radiation temperature of the radiation-emitting element to a desired value by using the setting element 150. The setting element 150 may in particular be connected to the control unit 120 via a wired connection and / or a wireless connection.

[0127] The heating system 110 may further comprise at least one notification unit 152. The notification unit 152 may be configured to provide at least one further information to at least one user of the heating system 110. As an example, the notification unit 152 may be configured to display the actual value and / or the predefined value and / or the desired value of the radiation temperature of the radiation-emitting element 114. Alternatively or additionally, the notification unit 152 may be configured to display at least one warning that may assume, accidentally or intentionally, the position of at least one cooking utensil 122 on the transfer material 116 used as a cooking surface, and may result in a potential fire hazard; the presence of at least one further object, such as a plastic container or a burn mark; or the operation of the cooking surface is thereby hindered. The notification unit 152 may in particular be connected to the control unit 120 via a wired connection and / or a wireless connection.

[0128] Figure 2 shows, again very diagrammatically, a further exemplary embodiment of a heating system 110 comprising at least one device 112 for monitoring the radiant temperature of at least one radiation-emitting element 114 according to the invention. The embodiment shown in Figure 2 is similar to the embodiment shown in Figure 1, so that for a number of components reference can be made to the description of Figure 1 above.

[0129] The device 112 may in particular comprise one or more radiation sensitive elements 126. The one or more radiation sensitive elements 126 may be covered by one or more individual optical filters 154. Each individual optical filter 154 may, for example, comprise a different material, and therefore may filter a different wavelength range of the thermal radiation before the thermal radiation is received by the one or more radiation sensitive elements 126. However, the individual optical filters 154 may be identical. Additionally or alternatively, the radiation sensitive elements 126 may be at least partially different radiation sensitive elements 126, and may differ in terms of sensitivity to different wavelengths of thermal radiation, for example, the radiation sensitive elements 126 may comprise at least partially different photosensitive materials. At least one radiation sensitive element 126 may be configured to receive thermal radiation emitted by at least one radiation emitting element 114, and at least one further radiation sensitive element (not shown here) may be configured to receive optical radiation emitted by at least one light source 125. Specifically, one radiation sensitive element 126 may be configured to receive thermal radiation emitted by at least one radiation emitting element 114, and one further radiation sensitive element may be configured to receive optical radiation emitted by at least one light source 125.

[0130] As shown in Fig. 2, the device 112 may further comprise at least one further radiation sensitive element 160. The at least one further radiation sensitive element 160 may be designated to generate at least one further sensor signal depending on the intensity of the further thermal radiation emitted by the at least one transition material 116 in at least one further wavelength range. The at least one further radiation sensitive element 160 may be covered by at least one of the individual optical filters 154. The at least one transition material 116 may not be transparent or may only be partially transparent to the thermal radiation emitted by the radiation emitting element 114 in at least one further wavelength range. The at least one evaluation unit 138 may further be configured to take into account the at least one further sensor signal measured by the at least one further radiation sensitive element 160 when determining the radiation temperature of the at least one radiation emitting element 114. The at least one evaluation unit 138 may further be configured to correct the intensity of the thermal radiation and / or the optical radiation by removing the contribution of the intensity of further thermal radiation emitted by the at least one transition material 116 from the intensity of the thermal radiation emitted by the at least one radiation emitting element 114 and the optical radiation emitted by the at least one light source 125.

[0131] The device 112 may further comprise at least one temperature sensor 162. The at least one temperature sensor 162 may be designated to monitor the temperature of the transition material 116. Thus, the temperature sensor 162 may be thermally coupled to the transition material 116. In particular, the temperature sensor 162 may be attached to the transition material 116. Additionally or alternatively, the temperature sensor 162 may be designated to monitor the temperature of the radiation sensitive element 114 or further components of the heating system 110. The at least one evaluation unit 138 may further be configured to take into account the temperature measured by the at least one temperature sensor 162 when determining the radiation temperature of the at least one radiation-emitting element 114. The at least one temperature sensor 162 may in particular be designated to monitor the temperature of a portion of the at least one transition material 116 that is passed by an optical path between the at least one radiation-emitting element 114 and the at least one radiation sensitive element 126.

[0132] The device 112 may further comprise at least one reference radiation sensitive element 164. The at least one reference radiation sensitive element 164 may have at least one covered sensor area 166. The at least one covered sensor area 166 may comprise the same photosensitive material as the at least one radiation sensitive element 126, but may be covered to prevent the reference radiation sensitive element 164 from receiving thermal radiation emitted by the at least one radiation emitting element 114 and the optical radiation emitted by the at least one light source 125. The at least one covered sensor area 166 may be designated to generate at least one reference signal. The at least one evaluation unit 138 may further be configured to take into account the at least one reference signal when determining the radiation temperature of the at least one radiation emitting element 114. The at least one covered sensor area 166 may be covered by a radiation absorbing layer 168 and / or a radiation reflecting layer 170. The radiation absorbing layer 168 may be designed to absorb thermal radiation and / or optical radiation. Radiation reflective layer 170 may be designed to reflect thermal and / or optical radiation.

[0133] The device 112 may further comprise at least one presence sensor 172. The at least one presence sensor 172 may be configured to determine at least one further object arranged such that the thermal radiation passes through the at least one further object before it can be received by the at least one radiation sensitive element 126. The at least one further object may be non-transparent or partially transparent in the thermal radiation emitted by the at least one radiation emitting element 114 and / or the optical radiation emitted by the at least one light source 125. The at least one further object may be selected from at least one of a plastic container or a burn mark located on the ceramic material 130. The at least one presence sensor 172 may be selected from at least one of a time-of-flight detector, a presence detector, or a proximity detector.

[0134] The device 112 may further comprise at least one thermoelectric cooler 174. The thermoelectric cooler 174 may be configured to cool the at least one radiation sensitive element 126 and / or the at least one light source 125. The at least one radiation sensitive element 126 and / or the at least one light source 125 may be thermally coupled to the thermoelectric cooler 174. In particular, the at least one radiation sensitive element 126 and / or the at least one light source 125 may be attached to the thermoelectric cooler 174. Furthermore, the thermoelectric cooler 174 may be configured to cool the at least one further radiation sensitive element 160. The at least one further radiation sensitive element 160 may be thermally coupled to the thermoelectric cooler 174. In particular, the at least one further radiation sensitive element 160 may be attached to the thermoelectric cooler 174.

[0135] The device 112 may further comprise at least one optical radiation shield 175. The optical radiation shield 175 may be configured to prevent at least one of the at least one radiation sensitive element 126 and the at least one further radiation sensitive element 160 from being directly irradiated by optical radiation emitted by the at least one light source 125. The optical radiation shield 175 may comprise at least one solid material that absorbs and / or reflects optical radiation, for example a synthetic plastic material or a metal. The optical radiation shield 175 may be arranged between the light source 125 and the at least one radiation sensitive element 126 and / or the at least one further radiation sensitive element 160.

[0136] Fig. 3 shows experimental data obtained by measuring a preferred embodiment of a preferred embodiment of a heating system 110 comprising a device 112 for monitoring the radiant temperature of at least one radiation-emitting element 114 according to the invention. In particular, Fig. 3 shows the wavelength dependence of some optical variables. Firstly, the theoretical spectral irradiance SI of a black body at 80°C is shown with reference 176. A black body may be any idealized physical body that absorbs all incident radiation. As will be appreciated by those skilled in the art, such a black body emits radiation according to Planck's law, meaning that it has a spectrum that is determined only by the temperature and not by the shape or composition of the black body. As Fig. 3 shows, the spectral irradiance SI increases strongly when the wavelength λ exceeds about 2000 nm.

[0137] Furthermore, FIG. 3 shows the measured external quantum efficiency (EQE) of the PbS detector, indicated by reference number 178. As the skilled person will appreciate, EQE refers to the ratio of the number of charge carriers generated by the detector to the number of incident photons at a particular wavelength λ. As FIG. 3 shows, the EQE of the PbS detector is maximum near 2600 nm and then rapidly decreases again at higher wavelengths λ. This behavior matches well with the transmission spectrum of the particular ceramic material used in the present invention, selected from the LAS system known as CERAN®, indicated by reference number 180. As FIG. 3 shows, the transmission of this particular ceramic material also drops sharply past near 2600 nm. Above 2800 nm, this particular ceramic material blocks almost all radiation. As a result, the at least one further wavelength range in which the at least one further radiation sensitive element 160 as described above may operate may be selected from at least one wavelength beyond 2.8 μm to 3.2 μm.

[0138] 3 further illustrates exemplary transmission spectra of two individual optical filters 154, here denoted by reference numerals 182 and 184, respectively. Here, the transmission spectra 182, 184 correspond to at least two individual wavelength ranges, which may preferably include a first individual wavelength range and a second individual wavelength range. As an example, the at least one photoconductive material may include lead sulfide (PbS), and the transmission spectra 182, 184 may be selected from wavelengths of 0.8 μm to 2.8 μm. As a further example, the at least one photoconductive material may include lead selenide (PbSe), and the transmission spectra 182, 184 may be selected from wavelengths of 0.8 μm to 5 μm.

[0139] As further shown in Fig. 3, each individual optical filter 154 may have a narrow transmission window. Wavelengths λ within the transmission window may pass through the individual optical filter 154 so as to be received by the radiation sensitive element 126. There may be no or only a small overlap between the transmission windows of the different individual optical filters 154. Thus, the individual wavelength ranges received by the radiation sensitive element 126 behind the individual optical filters 154 may be clearly defined with respect to each other. Alternatively, one of the transmission spectra may be completely included by the transmission spectrum of the other (not shown here).

[0140] FIG. 4 shows a schematic representation of a preferred embodiment of a method for heating at least one radiation-emitting element 114 to a radiation temperature including a method for monitoring the radiation temperature of at least one radiation-emitting element 114 according to the present invention.

[0141] The method for heating at least one radiation-emitting element 114 to a radiation temperature comprises the following steps: - a monitoring step 186 of monitoring the radiation temperature of at least one radiation emitting element 114, which emits thermal radiation at a radiation temperature; - a control step 188, comprising controlling the output of the at least one heating unit 110 based on the radiation temperature of the at least one radiation-emitting element 114 determined by the method of monitoring the radiation temperature of the at least one radiation-emitting element 114; Includes.

[0142] The control of the output of the at least one heating unit 110 may further comprise determining the presence of at least one further object, in particular a plastic container or a burn mark, apart from the at least one radiation-emitting element 114, by using the emissivity of the at least one radiation-emitting element 114. The control of the output of the at least one heating unit 110 may further comprise determining the presence of a boil-dry condition in the at least one radiation-emitting element 114 after the aqueous liquid has completely evaporated, by using the time course of the radiation temperature of the at least one radiation-emitting element 114, thereby opening the opportunity to prevent operation of the heating unit 110 after the presence has been confirmed.

[0143] The method for monitoring the radiant temperature of at least one radiation-emitting element 114 comprises the following steps: - generating 190 at least one sensor signal by using at least one radiation sensitive element 126 having at least one sensor area 128 comprising a photosensitive material selected from photoconductive materials, said at least one sensor area 128 being designated to generate at least one sensor signal in response to the intensity of thermal radiation, within at least one wavelength range, emitted by at least one radiation emitting element 114 and received by said sensor area 128; - an emitting step 191 comprising at least partially emitting optical radiation towards at least one radiation emitting element 114 by using at least one light source 125; - a further generating step 193 comprising generating at least one further sensor signal by using at least one radiation sensitive element 126, said sensor area 128 being further designated to generate at least one further sensor signal depending on the intensity of optical radiation emitted by at least one light source in at least one further wavelength range and received by the sensor area 128; - determining 192 a radiation temperature of the at least one radiation-emitting element 114 by evaluating the sensor signal of the at least one radiation sensitive element 126 by means of at least one evaluation unit 138, the at least one evaluation unit 138 being configured to determine the radiation temperature of the at least one radiation-emitting element 114 by using the intensity values ​​of the thermal and optical radiation; Includes. [Explanation of symbols]

[0144] 110 Heating System 112 Equipment 114 Radiation-emitting element 116 Transference Materials 118 Heating Unit 120 Control Unit 122 Cooking Utensils 124 Bottom 125 Light source 126 Radiation-sensitive element 127 Incandescent Lamp 128 Sensor Area 129 Thermal Infrared Emitter 130 Ceramic Materials 138 evaluation units 140 Heating Element 142 Opening 144 Induction Coil 146 Heat Shield 148 Aperture 150 Configuration Elements 152 Notification Unit 154 Individual Optical Filters 160 Further Radiation Sensitive Elements 162 Temperature Sensor 164 Reference Radiation Sensitive Element 166 covered sensor area 168 Radiation Absorbing Layer 170 Radiation reflective layer 172 Presence Sensor 174 Thermoelectric cooler 175 Optical Radiation Shield 176 Spectral irradiance of a black body at 80°C 178 External quantum efficiency (EQE) of PbS detector 180 Transmission spectrum of the ceramic material known as CERAN® 182 Exemplary Transmission Spectrum of a First Discrete Optical Filter 184 Exemplary transmission spectrum of a second discrete optical filter 186 Monitoring Steps 188 Control Steps 190 Generation Steps 191 Release Step 192 Decision Step 193 Further Generation Steps

Claims

1. An apparatus (112) for monitoring a radiation temperature of at least one radiation-emitting element (114), said at least one radiation-emitting element (114) emitting thermal radiation at a radiation temperature, said apparatus (112) comprising: at least one light source (125), said light source being configured to emit optical radiation at least partially towards said at least one radiation emitting element (114); at least one radiation sensitive element (126), said at least one radiation sensitive element (126) having at least one sensor area (128), said at least one sensor area (128) comprising at least one photosensitive material selected from at least one photoconductive material, said at least one sensor area (128) being designated to generate at least one sensor signal in response to an intensity of thermal radiation emitted by at least one radiation emitting element (114) and received by said sensor area (128) within at least one wavelength range, said sensor area (128) being adapted to receive at least one sensor signal in response to an intensity of thermal radiation emitted by said at least one light source (125) and received by said sensor area (128) within at least one further wavelength range; at least one radiation sensitive element (126) further configured to generate at least one further sensor signal in response to an intensity of optical radiation received by the at least one radiation sensitive element (126), the at least one radiation sensitive element (126) being positioned such that thermal radiation passes through the at least one transition material (116) before being received by the at least one radiation sensitive element (126), and at least one of the at least one light source (125) and the at least one radiation sensitive element (126) being positioned such that optical radiation passes through the at least one transition material (116) and impinges on the at least one radiation emitting element (114) before being received by the at least one radiation sensitive element (126); at least one evaluation unit (138), which is configured to determine a radiation temperature of said at least one radiation-emitting element (114) by using the values ​​of the intensities of said thermal radiation and of said optical radiation; and An apparatus (112).

2. The apparatus (112) of claim 1, wherein the at least one light source (125) is or includes an incandescent lamp (127) or a thermal infrared emitter (129), the thermal infrared emitter (129) being a micromachined thermal radiating device having a radiation emitting surface.

3. at least one further radiation sensitive element (126), which is designed to generate at least one further sensor signal dependent on the intensity of a further thermal radiation emitted by the at least one transition material (116) in at least one further wavelength range, and which is not transparent or is only partially transparent to the thermal radiation emitted by the radiation emitting element (114) in at least one further wavelength range of the further thermal radiation, Further equipped with The apparatus (112) of claim 1, wherein the at least one evaluation unit (138) is further configured to take into account the at least one further sensor signal measured by the at least one further radiation sensitive element (126) when determining the radiation temperature of the at least one radiation emitting element (114).

4. 2. The apparatus (112) of claim 1, wherein the at least one photoconductive material comprises lead sulfide, the at least one wavelength range and the at least one further wavelength range are selected from at least one wavelength from 0.8 μm to 2.8 μm, the at least one transition material (116) is selected from at least one ceramic material (130) used in ceramic glass countertops, and the at least one further wavelength range is selected from at least one wavelength from greater than 2.8 μm to 3.2 μm where the at least one ceramic material (130) is not transparent or only partially transparent to thermal radiation.

5. 2. The apparatus (112) of claim 1, wherein the at least one wavelength range of thermal radiation is completely encompassed by at least one further wavelength range of optical radiation, or vice versa.

6. The apparatus (112) of claim 1, wherein the at least one evaluation unit (138) is further configured to determine an emissivity of the at least one radiation emitting element (114), the emissivity being related to the effectiveness of the at least one radiation emitting element (114) for emitting thermal radiation.

7. The apparatus (112) according to claim 6, wherein the at least one evaluation unit (138) is configured to determine the emissivity of the at least one radiation emitting element (114) as a function of at least one further sensor signal in response to the intensity of the light radiation emitted by the at least one light source (125).

8. at least one temperature sensor (162), said at least one temperature sensor (162) comprising: said at least one radiation sensitive element (126); or said at least one transition material (116), at least one temperature sensor (162) designated to monitor the temperature of at least one of The apparatus (112) of claim 1, wherein the at least one evaluation unit (138) is further configured to take into account the temperature measured by the at least one temperature sensor (162) when determining the radiation temperature of the at least one radiation emitting element (114).

9. at least one reference radiation sensitive element (164), said at least one reference radiation sensitive element (164) having at least one covered sensor area (166), said at least one covered sensor area (166) comprising the same light sensitive material as said at least one radiation sensitive element (126) and being covered so as to prevent said reference radiation sensitive element (164) from receiving thermal radiation emitted by said at least one radiation emitting element (114), said at least one covered sensor area (166) being designated to generate at least one reference signal; Further equipped with The apparatus (112) of claim 1, wherein the at least one evaluation unit (138) is further configured to take the at least one reference signal into account when determining a radiation temperature of the at least one radiation-emitting element (114).

10. at least one presence sensor (172), configured to determine at least one further object arranged such that thermal radiation passes through the at least one further object before being received by the at least one radiation sensitive element (126), the at least one further object being non-transparent or partially transparent in at least one of the at least one wavelength range of the thermal radiation emitted by the at least one radiation emitting element (114) and the at least one further wavelength range of the optical radiation emitted by the at least one light source (125); The apparatus (112) of claim 1, further comprising:

11. at least one optical radiation shield (175), which is configured to shield the at least one radiation-emitting element (126) and the at least one further radiation-sensitive element (160) from direct illumination by optical radiation emitted by the at least one light source (125); The apparatus (112) of claim 1, further comprising:

12. A heating system (110) for heating at least one radiation-emitting element (114) to emit thermal radiation at a radiation temperature, the system comprising: at least one device (112) for monitoring a radiation temperature of at least one radiation-emitting element (114) according to any one of claims 1 to 11, said at least one radiation-emitting element (114) emitting thermal radiation at said radiation temperature; and at least one transition material (116), arranged such that thermal and optical radiation pass through the at least one transition material (116) before being received by the at least one radiation sensitive element (126), the at least one transition material (116) being at least partially transparent to thermal and optical radiation; at least one heating unit (118), said at least one heating unit (118) being designated to heat said at least one radiation-emitting element (114) via said at least one transition material (116); and at least one control unit (120), which is designed to control the power of the at least one heating unit (118) on the basis of a radiation temperature of the at least one radiation-emitting element (114) determined by the device (112) for monitoring the radiation temperature of the at least one radiation-emitting element (114); A system (110).

13. 13. The system (110) of claim 12, wherein the at least one heating unit (118) comprises at least one heating element (140) having at least one opening (142) designated to allow thermal radiation emitted by the at least one radiation emitting element (114) and light radiation emitted by the at least one light source (125) to pass through the at least one opening (142).

14. at least one thermal shield (146), which is designated to shield said at least one device (112) for monitoring the radiant temperature of said at least one radiation-emitting element (114) from said at least one heating unit, said at least one thermal shield (146) comprising at least one opening (148) designated to allow the thermal radiation emitted by said at least one radiation-emitting element (114) and the optical radiation emitted by at least one light source (125) to pass through said at least one opening (148); The system of claim 12 further comprising:

15. A method for monitoring a radiation temperature of at least one radiation-emitting element (114), the at least one radiation-emitting element (114) emitting thermal radiation at a radiation temperature, the method comprising the steps of: - generating at least one sensor signal by using at least one radiation sensitive element (126), said at least one radiation sensitive element (126) having at least one sensor area (128), said at least one sensor area (128) comprising a photosensitive material selected from photoconductive materials, said at least one sensor area (128) being designated to generate at least one sensor signal depending on the intensity of thermal radiation emitted by at least one radiation emitting element (114) and received by said sensor area (128) within at least one wavelength range; - emitting optical radiation, by using at least one light source (125), directed at least in part towards said at least one radiation emitting element (114); - generating at least one further sensor signal by using said at least one radiation sensitive element (126), said sensor area (128) being configured to generate at least one further sensor signal depending on the intensity of optical radiation emitted by at least one light source (125) and received by said sensor area (128) within at least one further wavelength range; determining a radiation temperature of the at least one radiation-emitting element (114) by evaluating the sensor signal of the at least one radiation sensitive element (126) by using at least one evaluation unit (138), the at least one evaluation unit (138) being configured to determine the radiation temperature of the at least one radiation-emitting element (114) by using intensity values ​​of thermal radiation and of light radiation; A method comprising:

16. generating at least one further sensor signal as a function of the intensity of further thermal radiation emitted by at least one transition material (116) in at least one further wavelength range, said at least one transition material (116) being non-transparent or only partially transparent to the thermal radiation emitted by said radiation-emitting element (114) in at least one further wavelength range of said further thermal radiation; determining the radiation temperature of said at least one radiation-emitting element (114) by taking said at least one further sensor signal into account when determining the radiation temperature of said at least one radiation-emitting element (114); The method of claim 15 further comprising:

17. A method for heating at least one radiation-emitting element (114) to emit thermal radiation at a radiation temperature, the method comprising the steps of: - monitoring a radiation temperature of at least one radiation-emitting element (114) according to claim 16, said at least one radiation-emitting element (114) emitting thermal radiation at said radiation temperature; - controlling the output of at least one heating unit (118) based on the radiation temperature of at least one radiation-emitting element (114) determined by the method for monitoring the radiation temperature of at least one radiation-emitting element (114) according to claim 15 or 16, said at least one heating unit (118) being designated to heat said at least one radiation-emitting element (114) via at least one transition material (116), said at least one transition material (116) being arranged such that thermal radiation and optical radiation pass through said at least one transition material (116) before being received by at least one radiation sensitive element (126); A method comprising:

18. controlling the output of the at least one heating unit (118); at least one further object separate from said at least one radiation-emitting element by using the emissivity of said at least one radiation-emitting element (114); or the boil-dry state of said at least one radiation-emitting element (114) after the aqueous liquid has completely evaporated, by using the time course of the radiation temperature of said at least one radiation-emitting element (114); determining the existence of; preventing operation of the at least one heating unit (118) after the presence is confirmed; and 20. The method of claim 17, further comprising:

Images