Spectral sensing device and method for measuring optical radiation - Patents.com

Abstract

The present invention relates to a spectral sensing device (110) and method for measuring optical radiation (112), the optical radiation (112) provided by at least one measurement object (114) comprising unmodulated optical radiation (116). The spectral sensing device (110) comprises: - at least one radiation-emitting element (118), said at least one radiation-emitting element (118) being designed to emit modulated light radiation (120); and - at least one photosensitive detector (124), the at least one photosensitive detector (124) having at least one photosensitive area (126) designated to receive the light radiation (112), and at least one detector signal generated by the at least one photosensitive detector (124) depending on the illumination of the at least one photosensitive area (126); - at least one evaluation unit (128), which is configured to generate at least one measurement information regarding the irradiation of the at least one photosensitive area (126) by the optical radiation (112) provided by the at least one measurement object (114) by using at least one modulated detector signal generated by the irradiation of the at least one photosensitive area (126) by the superposition of the modulated optical radiation (120) and the optical radiation (112) provided by the at least one measurement object (114). The spectral sensing device (110) is positioned such that modulated optical radiation (120) is directed within the spectral sensing device (110) towards the at least one photosensitive detector (124). The spectral sensing device (110) and method for measuring optical radiation (112) is configured to perform self-calibration of the spectral sensing device, preferably in a fully automated manner, without the need for predefined reflective targets.

Description

[Technical field]

[0001] The present invention relates to a spectral sensing device and method for measuring optical radiation, which can be used for surveillance or monitoring purposes in general, particularly in the infrared (IR) spectral region, and in particular in the near infrared (NIR) spectral region, as well as for the detection of heat, flame, fire or smoke. However, further types of applications are possible. [Background technology]

[0002] In particular, known spectral sensing devices, such as spectrometer systems that can be used for diffuse reflectance spectroscopy, are typically calibrated for the wavelength-dependent sensitivity of at least one detection element included in the spectral sensing device. Exemplary spectrometer systems are disclosed in US 2014 / 131578 A1, WO 2019 / 115594 A1, WO 2019 / 115595 A1, or WO 2019 / 115596 A1, although further types of spectral sensing devices are also known.

[0003] In practice, the spectral sensing device may be subject to drift effects that may be primarily caused by changes that may be related to or affect the spectral sensing device itself. In particular, the changes may include at least one of the following: degradation of at least one of the radiation source or detector elements contained in the device; temperature drift of at least one of the radiation source or detector elements; variations in the ambient temperature that affect the device; variations in the device temperature, i.e. the temperature at which at least one detector and the corresponding electronics may operate; mechanical expansion and contraction of at least one component contained in the device, in particular at least one of the mechanical housings, holders, or optical elements, in particular at least one dispersive element such as a prism, beam splitter, or diffraction grating. Furthermore, electrochemical processes, or physical processes such as relaxation of long-lived traps, may lead to drift effects. However, further types of changes are also conceivable.

[0004] In particular, the measurement of the optical radiation by the spectral sensing device may include a resistance measurement to read out a photosensitive detector, which includes, as an example, a lead sulfide photoconductor. The resistance measurement may be carried out in comparison with a further resistance, in particular by using a strong bias voltage in a circuit with at least one voltage divider. In such a configuration, the resistance of the photosensitive detector may be subject to drift effects, which may distort the measurement data, especially if not periodically corrected. Furthermore, noise, especially 1 / f noise, also known as flicker noise, may distort the measurement data.

[0005] In practice, drift effects need to be corrected from time to time through a process usually denoted by the term "calibration", in particular to maintain the reliability of the measurement data by avoiding that drift effects distort the measurement data to such an extent that the results determined by the spectral sensing device become inconclusive. For this purpose, a light calibration and a dark calibration can preferably be performed from time to time. Here, different types of calibration measurements can be performed, which in particular require a predefined reflective target or an empty volume in front of at least one detector element to avoid reflected radiation reaching at least one detector element.

[0006] In particular, a calibration target is not required for recalibrating at least one of the dark current, dark noise or dark resistance in a "dark" measurement for a dark calibration. For a dark calibration, at least one radiation source is typically switched off. In contrast, for "light" measurements, in particular reflectance spectroscopy, a calibration target having a predefined reflectance spectrum to ensure a known and reproducible calibration signal is usually placed in the radiation path from at least one radiation source to at least one detector element in the same way as at least one measurement object used for a spectral measurement, whereby in particular the wavelength-dependent sensitivity of at least one photosensitive detector can be calibrated.

[0007] WO 2017 / 040431 A1 discloses a system and method for measuring the concentration and type of a substance in a sample at a sampling interface. The system includes a light source, one or more optics, one or more modulators, a reference, a detector, and a controller. The system and method can take into account drifts originating from the light source, the one or more optics, and the detector by sharing one or more components between different measurement paths. Furthermore, the system can distinguish between different types of drifts and eliminate erroneous measurements due to stray light by placing one or more modulators between the light source and the sample or reference. Furthermore, the system can detect substances along various positions and depths in the sample by mapping the detector pixels and micro-optics to positions and depths in the sample.

[0008] WO 2021 / 069544 A1: - an array of at least one photoconductor, each photoconductor being configured to exhibit an electrical resistance that depends on the illumination of its photosensitive area, and at least one photoconductor of the array being designated as a characteristic photoconductor; - at least one bias voltage source, the bias voltage source configured to apply at least one AC bias voltage to the characteristic photoconductor or at least one DC bias voltage to the characteristic photoconductor; - at least one photoconductor readout circuit, the photoconductor readout circuit configured to determine a characteristic photoconductor response voltage generated in response to a bias voltage, the response voltage being proportional to a variable characterizing the photoconductor array, the photoconductor readout circuit configured to determine the characteristic photoconductor response voltage during operation of the photoconductor array; The present invention discloses an apparatus comprising:

[0009] For calibration of a spectral sensing device, the user is typically responsible for positioning the calibration target and removing any objects that may be placed in the sensing range of the sensing device, which may require, among other things, that the user be familiar with such technical measures. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] US2014 / 131578A1 [Patent Document 2] WO2019 / 115594A1 [Patent Document 3] WO2019 / 115595A1 [Patent Document 4] WO2019 / 115596A1 [Patent Document 5] WO2017 / 040431A1 [Patent Document 6] WO2021 / 069544A1 Summary of the Invention [Problem to be solved by the invention]

[0011] The problem addressed by the present invention is therefore to provide a spectral sensing device and method for measuring optical radiation which at least substantially avoids the disadvantages of known devices and methods of this type.

[0012] In particular, it is desirable to have a spectral sensing device configured to improve the accuracy of generated measurement data by performing self-calibration of the spectral sensing device, preferably in a fully automated manner, without the need for pre-defined reflective targets or extensive user interaction. [Means for solving the problem]

[0013] This problem is solved by the invention with the features of the independent patent claims. Advantageous developments of the invention, which can be realized individually or in combination, are set out in the dependent claims and / or in the following description and detailed embodiments.

[0014] In a first aspect of the present invention, a spectral sensing device for measuring optical radiation is disclosed, the optical radiation being provided by at least one measurement object, the optical radiation being provided by the at least one measurement object comprising non-modulated optical radiation.

[0015] As used herein, the term "spectral" or "spectrum" refers to a section of the optical spectral range, where the spectrum is constituted by optical signals defined by signal wavelengths and corresponding signal intensities. In particular, the spectrum may include spectral information related to at least one measurement object, such as the type and composition of at least one material forming the at least one measurement object, and the spectral information may be determined by recording at least one spectrum related to the at least one measurement object. Thus, the term "spectral sensing device" generally relates to a device configured to determine spectral information by recording at least one measurement value of at least one signal intensity related to at least one corresponding signal wavelength of optical radiation and by evaluating at least one detector signal related to the signal intensity.

[0016] As further used herein, the term "optical radiation" generally refers to the section of electromagnetic radiation that is usually called the "optical spectrum range" and includes at least one of the visible spectrum range, the ultraviolet spectrum range, and the infrared spectrum range. The term "ultraviolet" generally refers to electromagnetic radiation having a wavelength between 1 nm and 380 nm, preferably between 100 nm and 380 nm. Furthermore, the term "visible" generally refers to a wavelength between 380 nm and 760 nm. Furthermore, the term "infrared" (abbreviated IR) generally refers to a wavelength between 760 nm and 1000 μm, the wavelength between 760 nm and 3 μm being usually called "near infrared" and also abbreviated as "NIR". Preferably, the optical radiation used for typical purposes of the present invention is IR radiation, more preferably NIR radiation, in particular having a wavelength between 760 nm and 5 μm, preferably between 1 μm and 3 μm.

[0017] As further used herein, the term "modulation" refers to a process of varying the total power of a signal, preferably periodically, in particular at least one modulation frequency. The signal may be an electrical signal. The signal may be an optical signal, in particular an illumination. In particular, the periodic modulation can be performed between a maximum and a minimum value of the total power of the illumination. The minimum value can be 0, but can also be >0, so that, for example, a complete modulation does not have to be performed. The modulation can be performed in a radiation source designated to generate a desired modulated illumination, in particular via a modulated intensity and / or total power, for example a periodically modulated total power. Furthermore, modulation devices based on electro-optical and / or acousto-optical effects can also be used. Furthermore, at least one of a periodic beam interruption device, in particular a beam chopper, an interruption blade or an interruption wheel, can also be used. The modulation of the signal can in particular facilitate the detection of the signal and its differentiation from further signals. Thus, through the modulation of the signal, noise, in particular 1 / f noise, can be significantly reduced.

[0018] As a result, the term "non-modulated" as used herein generally refers to an unmodulated entity, specifically to unmodulated illumination, more specifically to unmodulated optical radiation provided by at least one measurement object. The term "measurement object" as used herein generally refers to any object chosen from living and non-living objects, including the material under investigation by the spectral sensing device. In particular, the at least one measurement object may be or may comprise at least one thermal emitter, e.g. a metal plate on a heater, that emits unmodulated thermal radiation according to Planck's law. In such a case, the spectral sensing device for measuring optical radiation can be used in particular to determine the temperature of the at least one measurement object. As the skilled person knows, electrical modulation of a thermal emitter, such as an incandescent lamp, can significantly reduce its lifetime by repeated switching processes. Furthermore, mechanical modulation, e.g. via a beam chopper, can become unstable due to exposure to heat. Thus, modulating the at least one measurement object may not be appropriate in many cases. In further cases, modulation of the at least one measurement object may not even be possible by reasonable means. As an example going in this direction, the at least one measurement object may comprise at least one cookware, which may be placed on a countertop. In such a case, it is particularly desired to measure at least one temperature of the at least one measurement object, which may be derived from the emissivity of the at least one measurement object, as known to those skilled in the art.

[0019] As mentioned above, the optical radiation is provided by at least one measurement object. Thus, as indicated above, the optical radiation provided by the at least one measurement object may be specifically emitted by the at least one measurement object. The optical radiation emitted by the at least one measurement object may indicate at least one physical property of the at least one measurement object, specifically the temperature of the at least one measurement object. However, additionally and / or alternatively, the optical radiation provided by the at least one measurement object may also be reflected by and / or transmitted through the at least one measurement object. Specifically, the at least one measurement object may be illuminated by at least one external light source that emits optical radiation that may include non-modulated optical radiation. The optical radiation emitted by the at least one external light source may be scattered by the at least one measurement object. Specifically, the at least one measurement object may at least partially reflect the optical radiation toward the spectral sensing device. Furthermore, the at least one measurement object may at least partially transmit the optical radiation toward the spectral sensing device. Thus, in summary, the optical radiation provided by the at least one measurement object may be at least one of: emitted by the at least one measurement object, reflected by the at least one measurement object, and transmitted through the at least one measurement object. Furthermore, the at least one measurement may at least partially absorb the optical radiation emitted by the external light source, and the at least one measurement may in particular indicate a composition of at least one material forming the at least one measurement object.

[0020] Thus, a spectral sensing device: - at least one radiation-emitting element, said at least one radiation-emitting element being designed to emit modulated light radiation; and - at least one photosensitive detector, the at least one photosensitive detector having at least one photosensitive area designated to receive light radiation, and at least one detector signal generated by the at least one photosensitive detector depending on illumination of the at least one photosensitive area; at least one evaluation unit, which is configured to generate at least one measurement information on the illumination of the at least one light-sensitive area by the optical radiation provided by the at least one measurement object by using at least one modulated detector signal generated by illumination of the at least one light-sensitive area by a superposition of the modulated optical radiation and the optical radiation provided by the at least one measurement object; Equipped with.

[0021] Here, the spectral sensing device is arranged such that the modulated light radiation is directed towards at least one photosensitive detector within the spectral sensing device.

[0022] As shown, the spectral sensing device comprises at least one radiation-emitting element. The at least one radiation-emitting element is designated to emit modulated light radiation. The at least one radiation-emitting element can be embodied in various ways. The at least one radiation-emitting element can be part of the spectral sensing device in the housing. Alternatively or additionally, the at least one radiation-emitting element can also be configured outside the housing, for example as a separate radiation-emitting element. The at least one radiation-emitting element can be configured to provide sufficient emission in a desired spectral range, preferably in the optical spectral range defined above or in at least one selected section thereof. The at least one radiation-emitting element may in particular be comprised by at least one of a thermal emitter 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 emitter may be selected from at least one of an incandescent lamp or a thermal infrared emitter, in particular: as further used herein, the term "thermal infrared emitter" refers to a micromachined thermal radiating device that includes a radiation emitting surface as a radiation emitting element that emits the optical radiation to be monitored. In particular, thermal infrared emitters can be obtained from Axetris AG, Schwarzen-bergstrasse 10, CH-6056 Kaegiswil, Switzerland under the name "emirs 50", or from LASER COMPONENTS GmbH, Werner-von-Siemens-Str.15 82140 Olching, Germany under the name "thermal infrared emitters", or from Hawkeye Technologies, 181 Research Drive #8, Milford CT 06460, USA under the name "infra-red emitters". However, further types of radiation emitting elements, such as structured light sources, may also be possible.

[0023] The at least one radiation-emitting element may be a continuous light source or alternatively a modulated 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 modulated light source, a modulation device may be used, which may be designated to modulate the illumination, preferably by generating a periodic modulation. As already indicated above, the modulation can be preferably performed within a light source designated to generate the desired modulated illumination, preferably by at least one radiation-emitting element having a modulated intensity and / or total power itself, for example a periodically modulated total power, and / or by at least one radiation-emitting element embodied as a modulated illumination source, for example a modulated laser. As a further example of irradiation, WO 2021 / 110721 A1 discloses at least one radiation-emitting element designed to generate light radiation when heated by an electric current; a 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 mount comes into contact. As mentioned above, 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, periodic beam interruption devices can also be used, in particular at least one of a beam chopper, a blocking blade or a blocking wheel.

[0024] Further according to the invention, the spectral sensing device comprises at least one photosensitive detector. The at least one photosensitive detector has at least one photosensitive area designated to receive optical radiation. The at least one detector signal generated by the at least one photosensitive detector depends on the illumination of the at least one photosensitive area. As generally used, the term "photosensitive detector" refers to a photodetector comprising at least one photosensitive area, which is designated to generate at least one detector signal in response to illumination of said at least one photosensitive area, which may in particular be provided to an evaluation unit for evaluation. The at least one photosensitive area included in the at least one photosensitive detector may preferably be a uniform photosensitive area, which is configured to receive the emitted optical radiation incident on the photosensitive area. However, multiple photosensitive areas are also possible, such as an area of ​​pixel-sized photosensitive areas. The at least one photosensitive detector is designated to generate a detector signal, preferably an optical signal or an electronic signal, which is related to the intensity of the emitted optical radiation impinging on the at least one photosensitive detector. The detector signal may be an analog signal and / or a digital signal. In certain embodiments, the at least one photosensitive detector may be or may include an active sensor, for example adapted to amplify the electronic signal before providing it to an external evaluation unit. For this purpose, the at least one photosensitive detector may be equipped with one or more signal processing devices, in particular one or more filters and / or analog-digital converters for processing and / or pre-processing the electronic signal.

[0025] The at least one photosensitive detector can be selected from any known light sensor, in particular from inorganic camera elements, preferably from inorganic camera chips, more preferably from CCD chips or CMOS chips, which are commonly used today in various cameras. Alternatively, the at least one photosensitive detector, in particular the at least one photosensitive region, can comprise a photoconductive material, in particular an inorganic photoconductive material selected from lead sulfide (PbS), lead selenide (PbSe), germanium (Ge), indium gallium arsenide (InGaAs, including but not limited to extended InGaAs), indium antimonide (InSb) or mercury cadmium telluride (HgCdTe or MCT). As commonly used, the term "extended InGaAs" refers to a specific type of InGaAs that exhibits a spectral response up to 2.6 μm. However, different kinds of materials or other types of photosensitive detectors are also possible.

[0026] Further according to the invention, the spectral sensing device comprises at least one evaluation unit. As generally used, the term "evaluation unit" refers to a device designated to determine at least one information, in particular spectral information, i.e. information related to the spectrum of a measurement object, the spectrum of which has been recorded in particular by using at least one photosensitive detector as described herein (the information being obtained by evaluating at least one detector signal or measurement information generated by at least one photosensitive detector), spectral information, or calibration information as defined elsewhere in this specification. The evaluation unit may be or comprise at least one integrated circuit, in particular an application specific integrated circuit (ASIc), or a data processing device, in particular at least one digital signal processor (DSP), field programmable gate array (FPGa), microcontroller, microcomputer, computer, or electronic communication unit, in particular at least one smartphone or tablet. Additional components, in particular at least one preprocessing device or data acquisition device, may be possible. Furthermore, the evaluation unit may comprise at least one interface, in particular at least one wireless interface or wired interface.

[0027] Furthermore, the evaluation unit can be designed to control or drive the spectral sensing device or parts thereof, completely or partially. The evaluation unit can be configured to control at least one radiation-emitting element and / or at least one photosensitive detector. The evaluation unit can in particular be designed to perform at least one measurement cycle in which a plurality of detector signals can be picked up. The information determined by the evaluation unit can in particular be provided to at least one further device or to a user, preferably in at least one of electronic, visual, acoustic or tactile manner. Furthermore, the information can be stored in at least one data storage unit, in particular an internal data storage unit included by the spectral sensing device, in particular by the at least one evaluation unit, or in a separate storage unit to which the information can be transmitted via at least one interface. The separate storage unit can be included by the at least one electronic communication unit. The storage unit can in particular be configured to store at least one electronic table, such as at least one look-up table.

[0028] The evaluation unit may preferably be configured to execute at least one computer program, in particular at least one computer program that executes or supports the step of generating information. By way of example, one or more algorithms may be implemented that can perform a conversion into information by using at least one detector signal as at least one input variable. For this purpose, the evaluation unit may comprise at least one data processing device, in particular at least one electronic or optical data processing device, that may be designed to generate information by evaluating at least one detector signal. The evaluation unit is thus designed to use at least one detector signal as at least one input variable and to generate information by processing the at least one input variable. The processing may be performed in succession, in parallel or in a combined manner. The evaluation unit may use any process for generating information, in particular by calculation and / or by using at least one stored and / or known relationship.

[0029] According to the invention, the at least one evaluation unit is configured to generate at least one measurement information regarding the illumination of the at least one photosensitive area by the optical radiation provided by the at least one measurement object by using at least one modulated detector signal generated by the illumination of the at least one photosensitive area by the superposition of the modulated optical radiation and the optical radiation provided by the at least one measurement object. The term "measurement information" as used herein generally refers to at least one of data, knowledge or evidence providing at least one qualitative and / or quantitative description of the at least one photosensitive detector, specifically the at least one photosensitive area, and the at least one measurement object. In particular, the at least one measurement information may relate to the responsivity of the at least one photosensitive detector. The term "responsivity" as used herein generally refers to the input / output gain of the detector, specifically the ratio of the power output of the at least one photosensitive detector per the optical power input. The responsivity may therefore indicate the response of the at least one photosensitive detector to the illumination of the at least one photosensitive area, specifically the illumination by the at least one measurement object. In particular, the responsivity of the at least one photosensitive detector may depend on the intensity of the optical radiation incident on the at least one photosensitive detector, in particular on the at least one photosensitive area. In general, therefore, the greater the intensity of the optical radiation incident on the at least one photosensitive detector, the greater the response of the at least one photosensitive detector may be. As already indicated, the optical radiation incident on the at least one photosensitive detector may in particular be a superposition of optical radiation from different sources, in particular a superposition of modulated optical radiation and of optical radiation provided by the at least one measurement object. In particular, the at least one measurement information may comprise at least one of the change in resistance ΔR of the at least one photosensitive detector and at least one responsivity-dependent quotient of the at least one photosensitive detector. The at least one responsivity-dependent quotient of the at least one photosensitive detector may in particular be a superposition of the change in resistance ΔR of the at least one photosensitive detector with respect to the DC resistance R of the at least one photosensitive detector. DCThe change in resistance ΔR of the at least one photosensitive detector may specifically be or may include the AC resistance of the at least one photosensitive detector. The total resistance of the at least one photosensitive detector may be the DC resistance R of the at least one photosensitive detector. DC and the change in resistance ΔR of the at least one photosensitive detector, specifically the AC resistance of the at least one photosensitive detector. Above and below, DC refers to direct current and AC refers to alternating current.

[0030] A change in resistance ΔR of the at least one photosensitive detector can be induced by superposition of the optical radiation provided by the at least one measurement object and the modulated optical radiation emitted by the at least one radiation-emitting element in the at least one photosensitive detector. As mentioned above, the optical radiation provided by the at least one measurement object includes non-modulated optical radiation. The non-modulated optical radiation is a change in the resistance ΔR of the at least one photosensitive detector. DC The modulated optical radiation emitted by the at least one radiation-emitting element may induce a change ΔR in the resistance of the at least one photosensitive detector. In particular, the at least one radiation-emitting element may be modulated periodically, more particularly at a specified modulation frequency. The modulated optical radiation emitted by the at least one radiation-emitting element may therefore induce in particular a periodic temporal change in the total resistance of the at least one photosensitive detector, in particular a change in the form of an AC resistance. Since the responsivity of the at least one photosensitive detector may decrease with increasing optical radiation from the measurement object, the change ΔR in the resistance of the at least one photosensitive detector may be proportional to the DC resistance R of the at least one photosensitive detector. DCAs an example, the optical radiation provided by the at least one measurement object may be strong enough to saturate the at least one photosensitive detector, so that the change in resistance ΔR of the at least one photosensitive detector is zero or at least very small. As a further example, the optical radiation provided by the at least one measurement object may be weak enough not to affect the at least one photosensitive detector, so that the change in resistance ΔR of the at least one photosensitive detector is very large.

[0031] As shown above, the change in resistance ΔR of the at least one photosensitive detector is proportional to the DC resistance R of the at least one photosensitive detector. DC Furthermore, when the at least one measurement object includes at least one thermal radiator, the DC resistance R of the at least one photosensitive detector may be a function of DC may be at least one function of the temperature of the at least one measurement object and the emissivity of the at least one measurement object. As used herein, the term "emissivity" relates to the effectiveness of the at least one radiation-emitting element to emit thermal radiation. More specifically, emissivity refers to the material property of the at least one radiation-emitting element due to the intensity of the thermal radiation emitted by the at least one radiation-emitting element. Generally, emissivity is indicated by a value between 0 and 1, where a value of 1 corresponds 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, and preferably greater than 0.9.

[0032] The spectral sensing device may further comprise at least one readout circuit configured to read out the at least one photosensitive detector, in particular the at least one photosensitive detector in a resistance measurement. The term "readout circuit" as used herein generally refers to any device configured to quantify and process at least one physical property and / or a change in the at least one physical property detected by at least one measuring device, in particular the at least one photosensitive detector. As mentioned above, the at least one photosensitive detector may specifically comprise at least one lead sulfide photoconductor. Photoconductors generally change their conductivity when irradiated and may therefore potentially change their resistance, which is quantified in a resistance measurement. Thus, by the measured resistance value, conclusions can be drawn regarding the incident light radiation. The resistance measurement may be performed in comparison with a further resistor, in particular a further resistor with a known resistance value. The further resistor may in particular be arranged in a voltage divider in the readout circuit.

[0033] The readout circuit specifically detects the DC resistance R of at least one photosensitive detector. DC and / or may be configured to measure a change in resistance ΔR of the at least one photosensitive detector. The readout circuit may include at least one of a resistance meter, a voltage divider, and a pass filter, particularly a high pass filter. The change in resistance ΔR of the at least one photosensitive detector may be specifically determined by a DC resistance R of the at least one photosensitive detector. DC The high-pass filter may be small compared to the DC resistance R DC can be filtered to pass only the smaller change ΔR in resistance of the at least one photosensitive detector.

[0034] As outlined above, the spectral sensing device is arranged such that the modulated light radiation is directed within the spectral sensing device towards at least one photosensitive detector. As commonly used, the term "direct" or grammatical variations thereof refers to causing the propagation of the light radiation in a desired direction, in particular by reflecting or transmitting a portion of the light radiation. The spectral sensing device may include at least one optical element configured to direct the modulated light radiation towards at least one photosensitive detector. The term "optical element" as used herein generally refers to any element configured to change at least one optical property of the incident light radiation, such as the intensity of the light radiation or the direction of at least a portion of the light radiation. At least one light radiation may be scattered at the optical element. At least one light radiation may be at least partially reflected by the optical element and / or transmitted through the optical element and / or absorbed by the optical element.

[0035] The interaction between the optical radiation and the at least one optical element may depend on at least one physical property of the optical radiation, in particular at least one of the angle of incidence of the optical radiation and / or at least one wavelength of the optical radiation. As a person skilled in the art will appreciate, the wavelength of the optical radiation may also be expressed in terms of optical frequency, wave number, or energy. The interaction between the optical radiation and the at least one optical element may further depend on at least one physical property of the at least one optical element, in particular the refractive index of the at least one optical element, the optical density of the at least one optical element, the thickness of the at least one optical element, and at least one surface condition of the at least one surface of the at least one optical element. The at least one optical element may be or include at least one of a mirror, a window, a lens, an aperture, a diffraction grating, a prism, and an optical filter. The at least one optical element may comprise at least one partially reflective optical element. The at least one partially reflective optical element may be designated to reflect the modulated optical radiation emitted by the at least one radiation-emitting element towards the at least one photosensitive detector. The at least one partially reflective optical element may be transparent to the optical radiation provided by the at least one measurement object, such that the optical radiation provided by the at least one measurement object can be transmitted through the at least one partially reflective optical element, in particular towards the at least one photosensitive detector.

[0036] At least one radiation-emitting element may be designated to emit modulated light radiation, so that the modulated light radiation may have a constant irradiance output. Specifically, the average irradiance output of the modulated light radiation may be constant over a larger time interval. The amplitude of the modulated light radiation may be specifically periodically modulated with a constant modulation frequency. As will be appreciated by those skilled in the art, the amplitude of light radiation is related to the irradiance output. Thus, within one period, the irradiance output of the modulated light radiation may naturally alternate. However, over a time interval that includes multiple periods, the average irradiance output may be specifically constant. More specifically, the maximum amplitude of the modulated light radiation may be constant, and the modulated light radiation may be specifically periodically modulated with a constant modulation frequency. The constant irradiance output may facilitate the evaluation of the modulated light radiation, since it is not necessary to consider the time variation of the irradiance output.

[0037] The spectral sensing device may comprise at least two individual photosensitive detectors. At least one photosensitive area of ​​the at least one first photosensitive detector may be designated to receive modulated light radiation. At least one photosensitive area of ​​the at least one second photosensitive detector may be designated to receive light radiation provided by the at least one measurement object and modulated light radiation. Thus, in this arrangement, the at least one second photosensitive detector may be used to generate at least one measurement information, while the at least one first photosensitive detector may be used to correct drift effects in the at least one second photosensitive detector. The at least one first photosensitive detector and the at least one second photosensitive detector may in particular be structurally identical or may at least have similar properties, in particular similar responsivity. For this purpose, at least one of a detector array, a multi-pixel system and a detector matrix may be used. Thus, the at least one photosensitive detector may comprise at least one of a detector array, a multi-pixel system and a detector-matrix. As used herein, the terms "first" or "second" are to be regarded as descriptions of elements without specifying an order or chronology or excluding the possibility that other elements of the same type may be present.

[0038] The spectral sensing device may further comprise at least one radiation separation element. The at least one radiation separation element may be designed and arranged to separate the modulated light radiation from the light radiation provided by the at least one measurement object. The at least one radiation separation element may comprise at least one first optical filter element. The at least one first optical filter element may be designed and arranged such that at least one light-sensitive region of the at least one first photosensitive detector receives only the modulated light radiation. The term "optical filter element" as used herein generally refers to any device configured to selectively block optical radiation depending on at least one physical property of the optical radiation, such as the wavelength of the optical radiation and / or the polarization of the optical radiation. Thus, the at least one first optical filter element may be configured to block the optical radiation provided by the at least one measurement object, and the at least one second optical filter element may be configured to block the modulated light radiation emitted by the at least one radiation-emitting element.

[0039] The at least one radiation separation element may include at least one non-transmissive optical element. The at least one non-transmissive optical element may be designated and arranged such that at least one light-sensitive area of ​​the at least one first light-sensitive detector receives only the modulated light radiation. In particular, the at least one non-transmissive optical element may be or may include at least one opaque material. The at least one non-transmissive optical element may in particular be opaque over a wavelength range that includes the wavelength range of the modulated light radiation emitted by the at least one radiation-emitting element and the wavelength range of the light radiation emitted by the at least one measurement object.

[0040] The spectral sensing device may further include at least one further radiation-emitting element. The at least one further radiation-emitting element may be designated to emit a further modulated light radiation. The at least one evaluation unit may be at least one modulated detector signal generated by illumination of at least one light-sensitive area by superposition of the optical radiation provided by the at least one measurement object with a further modulated optical radiation; and At least one measurement; The method may be further configured to generate at least one spectral information regarding the at least one measurement object by using

[0041] The spectral sensing device may particularly preferably be arranged in such a way that the further modulated light radiation is directed towards the at least one measurement object.

[0042] In particular, the spectral sensing device may be arranged such that the further modulated light radiation is directed towards the at least one measurement object such that the further modulated light radiation is subsequently reflected by the at least one measurement object towards the at least one photosensitive detector, in particular towards the at least one photosensitive region. The further modulated light radiation may thus provide information about at least one optical property of the measurement object, in particular at least one of reflectance, emissivity and absorptivity. The transmission of the light radiation through the at least one measurement object may be negligible, particularly in the case of metal surfaces. The emissivity may therefore be calculated as 1 minus the reflectance. As will be further appreciated by those skilled in the art, at least one of the reflectance, emissivity and absorptivity may be wavelength dependent.

[0043] For the term "spectral information", please refer to the explanation above. Generating the at least one spectral information on the at least one measurement object may include measuring the optical radiation provided by the at least one measurement object. In particular, the optical radiation provided by the at least one measurement object may be measured by determining a change ΔR in the resistance of the at least one photosensitive detector and / or calculating at least one responsivity-dependent quotient of the at least one photosensitive detector. More particularly, if the at least one measurement object comprises at least one thermal emitter, the temperature of the at least one measurement object may be derived from measuring a change ΔR in the resistance of the at least one photosensitive detector and / or calculating at least one responsivity-dependent quotient of the at least one photosensitive detector. This in particular allows to eliminate long-term drifts of non-modulated measurement objects. In particular, the measurement of the DC resistance of the at least one measurement object may still be performed as the main measurement method for measuring the optical radiation provided by the at least one measurement object, and the measurement of the DC resistance of the at least one measurement object may be calibrated at regular or irregular time intervals by using the at least one measurement information.

[0044] At least one evaluation unit further comprises generating at least one calibration information by further comparing the at least one modulated detector signal generated by illumination of the at least one photosensitive area with the modulated light radiation and at least one further modulated detector signal generated by illumination of the at least one photosensitive area with the further modulated light radiation; It can be configured.

[0045] As commonly used, the term "calibration" refers to the process of correcting drift effects from time to time that may occur in a spectral sensing device, mainly due to changes related to or affecting the spectral sensing device itself. The changes may include, in particular, at least one of the following: degradation of at least one of the radiation-emitting element or the photosensitive detector; temperature drift of at least one of the radiation-emitting element or the photosensitive detector; variations in the ambient temperature that affect the spectral sensing device; changes in the temperature related to the spectral sensing device, i.e. the temperature at which the at least one photosensitive detector and the corresponding electronics may operate; mechanical expansion and contraction of at least one component contained by the spectral sensing device, in particular the mechanical housing, holder, or at least one of the optical elements, in particular the mechanical expansion and contraction of the at least one optical window. However, there may also be further changes. Furthermore, electrochemical processes, or physical processes such as relaxation of long-lived traps, may cause drift effects. Correcting drift effects may particularly facilitate maintaining the reliability of the measurement data, in particular by avoiding that drift effects distort the measurement data to such an extent that the results determined by the spectral sensing device become inconclusive.

[0046] As a result, the term "piece of calibration information" as used herein generally refers to at least one of data, knowledge or evidence providing a qualitative and / or quantitative description of at least one entity, such as relating to a physical property of an element or object, that can be used for calibration. The at least one calibration information may be or include at least one of calibration coefficients, calibration curves or calibration functions, which may be stored in the data storage device as a calibration file, preferably in the form of at least one of a table, a set of values ​​and associated functions in a parameterized form or as a functional equation. The at least one calibration information may be recorded in a look-up table. In particular, the at least one calibration information may relate to the responsivity of the at least one photosensitive detector. The at least one photosensitive detector may be continuously calibrated by using at least one of the at least one calibration information, in particular at the same time as measuring the optical radiation provided by the at least one measurement object. The further modulated optical radiation emitted by the at least one further radiation-emitting element may differ from the modulated optical radiation emitted by the at least one radiation-emitting element, in particular in terms of modulation frequency. Thus, the at least one photosensitive detector can simultaneously detect in parallel and distinguish between both the further modulated light radiation emitted by the at least one further radiation-emitting element and the modulated light radiation emitted by the at least one radiation-emitting element. Also, the at least one photosensitive detector may be calibrated at regular or irregular time intervals by using the at least one calibration information.

[0047] In particular, the at least one further radiation-emitting element may be structurally identical to the at least one radiation-emitting element or may have at least similar properties, in particular light-emitting properties such as irradiation power and / or wavelength range. However, the modulation of the modulated light radiation emitted by the at least one radiation-emitting element may be specifically different compared to the further modulation of the modulated light radiation emitted by the at least one further radiation-emitting element. Thus, the modulated light radiation may be distinguishable from the further modulated light radiation when detected by the at least one photosensitive detector. In particular, the at least one radiation-emitting element and the at least one further radiation-emitting element may be modulated sequentially. Furthermore, the at least one radiation-emitting element and the at least one further radiation-emitting element may be modulated simultaneously with different modulation frequencies. The modulated light radiation emitted by the at least one radiation-emitting element may induce a change in resistance ΔR1 in the at least one photosensitive detector. The further modulated light radiation emitted by the at least one radiation-emitting element may induce a change in resistance ΔR2 in the at least one photosensitive detector. Thus, the at least one calibration information can be derived from comparing the change in resistance ΔR1 in the at least one photosensitive detector with the change in resistance ΔR2 in the at least one photosensitive detector. For further details regarding the at least one further radiation-emitting element, reference can be made to the description of the at least one radiation-emitting element provided above.

[0048] The at least one further radiation-emitting element may be designated to emit the further modulated light radiation such that the further modulated light radiation has a constant illumination power. The spectral sensing device may be arranged such that the further modulated light radiation is reflected by the at least one measurement object, in particular towards the at least one photosensitive detector. In this way, the at least one further radiation-emitting element may illuminate the at least one measurement object with the further modulated light radiation. The further modulated light radiation may be scattered at the at least one measurement object. In particular, the further modulated light radiation may be at least partially absorbed in the at least one measurement object, and the absorption may be characteristic of at least one physical property of the at least one measurement object, such as the composition of the at least one material forming the at least one measurement object. Thus, the modulated light radiation reflected by the at least one measurement object may carry at least one information regarding at least one physical property of the at least one measurement object. The modulated light radiation reflected by the at least one measurement object may include diffusely reflected light radiation carrying spectral information regarding the at least one measurement object. The modulated optical radiation reflected by the at least one measurement object may include optical radiation that carries emissivity information about the at least one measurement object, in particular directly reflected optical radiation via Fresnel reflection.

[0049] Thus, by comparing the change in resistance ΔR1 in the at least one photosensitive detector with the change in resistance ΔR2 in the at least one photosensitive detector, the optical radiation provided by the at least one measurement object may be further measured, and in particular, at least one of the chemical composition, emissivity, and temperature of the at least one measurement object may be determined. In particular, in the first measurement, the change in resistance ΔR1 in the at least one photosensitive detector and the change in resistance ΔR2 in the at least one photosensitive detector may be compared to calculate at least one responsivity-dependent quotient. In the second measurement, the at least one responsivity-dependent quotient may be weighed to calculate at least one of the chemical composition, emissivity, and temperature of the at least one measurement object.

[0050] The spectral sensing device may comprise at least two individual photosensitive detectors. At least one photosensitive region of the at least one further first photosensitive detector may be designated to receive the modulated light radiation. At least one photosensitive region of the at least one further second photosensitive detector may be designated to receive the further modulated light radiation and the light radiation provided by the at least one measurement object. The spectral sensing device may comprise at least one further radiation separation element. The at least one further radiation separation element may be designated and arranged to separate the modulated light radiation from the further modulated light radiation. The at least one further radiation separation element may in particular be structurally identical to the radiation separation element described above or may have at least similar properties, in particular optical properties. For further details regarding the further radiation separation element and its embodiments, reference may therefore be made to the radiation separation element and its embodiments provided above.

[0051] The at least one further radiation separation element may comprise at least one of at least one further first optical filter element and at least one further second optical filter element. The at least one further first optical filter element may be designed and arranged such that at least one photosensitive area of ​​the at least one further first optical sensitive detector receives only the modulated optical radiation. The at least one further second optical filter element may be designed and arranged such that at least one photosensitive area of ​​the at least one further second optical sensitive detector receives only the further modulated optical radiation and the optical radiation provided by the at least one measurement object.

[0052] The at least one further radiation separation element may comprise at least one further non-transmissive optical element which may be designed and arranged such that at least one light-sensitive area of ​​the at least one further first light-sensitive detector receives only the modulated light radiation and at least one light-sensitive area of ​​the at least one further second light-sensitive detector receives only the further modulated light radiation and the light radiation provided by the at least one measurement object.

[0053] The at least two individual photosensitive detectors may be arranged such that at least one photosensitive region of the at least one further first photosensitive detector receives only modulated light radiation, and at least one photosensitive region of the at least one further second photosensitive detector receives modulated light radiation, further modulated light radiation, and light radiation provided by at least one measurement object. The spectral sensing device may comprise two additional first individual photosensitive detectors. At least one photosensitive region of one of the at least two additional first photosensitive detectors can receive only modulated light radiation. At least one photosensitive region of another one of the at least two additional first photosensitive detectors can receive modulated light radiation and light radiation provided by at least one measurement object.

[0054] The spectral sensing device may comprise at least one further partially reflective optical element. The at least one partially reflective optical element may be designed to reflect the modulated light radiation emitted by the at least one radiation emitting element towards the at least one photosensitive detector and to transmit the further light radiation emitted by the at least one further emitting element towards the at least one measurement object. In particular, the reflection at the at least one further partially reflective optical element may be or may include Fresnel reflection. The term "Fresnel reflection" as commonly used refers to a type of light reflection as a result of an interface between at least two media having different refractive indices. The at least one further partially reflective optical element is transparent to the light radiation provided by the measurement object.

[0055] The spectral sensing device may further comprise at least one temperature stabilizing element. The at least one temperature stabilizing element may be designated to maintain at least one temperature of the at least one photosensitive detector, the at least one radiation-emitting element and, if appropriate, the at least one further radiation-emitting element at a constant level. Maintaining the temperature at a constant level may facilitate avoiding drift effects during the measurement. The term "temperature stabilizing element" as used herein generally refers to at least one of a heat sink and a heat pump, the heat pump being designated to actively transfer heat between at least two spatial regions, thereby generating a heat flux between the at least two spatial regions. The temperature stabilizing element may in particular be based on the Peltier effect to generate the heat flux. For this purpose, the temperature stabilizing element may in particular comprise at least one thermoelectric cooler. The direction of the heat flux may depend on the direction of the current applied to the thermoelectric cooler. Depending on the direction of the heat flux, the temperature stabilization element can be used to cool at least one spatial region by transferring heat to the at least one further spatial region or to heat at least one spatial region by transferring heat from the at least one further spatial region. However, further types of temperature stabilization elements may also be possible.

[0056] In a further aspect of the invention, a method for measuring optical radiation emitted by at least one measurement object is disclosed. The optical radiation emitted by the at least one measurement object comprises non-modulated optical radiation. The method for measuring optical radiation according to the invention comprises the following steps: a) emitting modulated optical radiation by using at least one radiation emitting element, the modulated optical radiation being directed towards at least one photosensitive detector within a spectral sensing device, the at least one photosensitive detector having at least one photosensitive area designated to receive optical radiation, and at least one detector signal generated by the at least one photosensitive detector being dependent on illumination of the at least one photosensitive area; b) generating, by means of at least one evaluation unit, at least one measurement information regarding the illumination of the at least one light-sensitive area by the light radiation provided by the at least one measurement object, by means of the superposition of the modulated light radiation and the light radiation provided by the at least one measurement object, by means of at least one detector signal generated by the illumination of the at least one light-sensitive area; Includes.

[0057] The method further comprises the steps of: c) emitting further modulated light radiation by using at least one further radiation emitting element, said further modulated light radiation being directed towards at least one measurement object; d) generating at least one spectral information about at least one measurement object, the step comprising: · at least one modulated detector signal generated by illumination of at least one light-sensitive area by superposition of the optical radiation provided by the at least one measurement object with a further modulated optical radiation; At least one measurement; and generating at least one spectral information about at least one measurement object by using at least one evaluation unit by using the at least one spectral information; may include:

[0058] The method further comprises the steps of: e) generating at least one calibration information by using the at least one evaluation unit by further comparing the at least one detector signal generated by illumination of the at least one photosensitive area with the modulated light radiation with at least one further detector signal generated by illumination of the at least one photosensitive area with a further modulated light radiation. may include:

[0059] Steps a)-e) can be performed sequentially or non-sequentially, and steps a)-e) can be performed at least partially simultaneously. Specifically, when steps c)-e) are performed, steps a) and c) can be performed simultaneously, and steps b) and e) can be performed simultaneously before finally performing step d). Furthermore, additional steps can also be performed, whether or not described herein.

[0060] In step e), at least one calibration information is - a modulated light radiation and a further modulated light radiation differing by at least one modulation frequency; at least one first photosensitive region and at least one second photosensitive region differing by at least one spectral sensitivity; by distinguishing at least one detector signal from at least one further detector signal by using at least one of

[0061] In a further aspect, the present invention relates to a computer program comprising executable instructions that, when the program is executed by a computer, cause the computer to execute the steps of the method for measuring optical radiation described elsewhere herein. The computer program comprising the executable instructions may preferably be fully or partially integrated in an evaluation unit, in particular a data processing device, in particular a computer or an electronic communication unit, in particular a smartphone or a tablet. The computer program may be capable of executing the method by using at least one data processing device already included in the evaluation unit, in particular an electronic communication unit. By way of example, the method may be executed on the electronic communication unit as an application, also indicated by the term "app".

[0062] In a further aspect of the present invention, the use of the spectral sensing device according to the present invention is disclosed. It is proposed to use the spectral sensing device for determining information, in particular spectral information, about at least one measurement object. Here, the spectral sensing device is preferably used for a use selected from the group consisting of: infrared detection applications; spectroscopy applications; exhaust gas monitoring applications; combustion process monitoring applications; pollution monitoring applications; industrial process monitoring applications; mixing or blending process monitoring applications; chemical process monitoring applications; food treatment process monitoring applications; food preparation process monitoring applications; water quality monitoring applications; air quality monitoring applications; quality control applications; temperature control applications; motion control applications; exhaust control applications; gas detection applications; gas analysis applications; motion sensing applications; chemical sensing applications; mobile applications; medical applications; mobile spectroscopy applications; food analysis applications; agricultural applications, in particular soil, silage, feed, crop or agricultural product characterization, plant health monitoring; plastic identification and / or recycling applications. However, further applications are also possible.

[0063] For further details regarding the use of the method for measuring optical radiation, the corresponding computer program and the spectral sensing device according to the present invention, respectively, reference may be made to the description of the spectral sensing device for measuring optical radiation provided elsewhere in this specification.

[0064] The spectral sensing device and method for measuring optical radiation disclosed herein have considerable advantages over the prior art. The spectral sensing device and method according to the invention are configured to perform self-calibration, preferably in a fully automated manner, without the need for predefined reflective targets. Furthermore, modulation of the signal may lead to a reduction of noise, in particular 1 / f noise. In particular, the spectral sensing device and method may be used to increase the reliability of the measurement results of the spectral sensing device and multi-pixel sensing solution, in particular to enable self-calibration of IR sensing modules based on multi-pixel solutions. As a result, the spectral sensing device and method disclosed herein may facilitate the use and calibration of the device by the user. Thus, this kind of spectral sensing device may be routinely used in household appliances.

[0065] 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.

[0066] 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.

[0067] In summary, in the context of the present invention, the following embodiments are considered to be preferred:

[0068] Embodiment 1: A spectral sensing device for measuring optical radiation provided by at least one measurement object, the optical radiation provided by the at least one measurement object comprising non-modulated optical radiation, the spectral sensing device comprising: - at least one radiation-emitting element, said at least one radiation-emitting element being designed to emit modulated light radiation; and - at least one photosensitive detector, the at least one photosensitive detector having at least one photosensitive area designated to receive light radiation, and at least one detector signal generated by the at least one photosensitive detector depending on illumination of the at least one photosensitive area; at least one evaluation unit, which is configured to generate at least one measurement information on the illumination of the at least one photosensitive area by the optical radiation provided by the at least one measurement object by using at least one modulated detector signal generated by illumination of the at least one photosensitive area by superposition of the modulated optical radiation and the optical radiation provided by the at least one measurement object, The spectral sensing device is positioned such that modulated light radiation is directed within the spectral sensing device towards the at least one photosensitive detector.

[0069] Embodiment 2: The spectral sensing device of the preceding embodiment, wherein the at least one radiation emitting element is comprised by at least one of a thermal emitter or a semiconductor-based radiation source.

[0070] Embodiment 3: The spectral sensing device according to the preceding embodiment, wherein the at least one semiconductor-based radiation source is selected from at least one of a light emitting diode (LED) or a laser, in particular a laser diode.

[0071] Embodiment 4: A spectral sensing device according to any one of the preceding embodiments, wherein the at least one photosensitive detector is selected from known light sensors, in particular from inorganic camera elements, preferably from inorganic camera chips, more preferably from CCD chips or CMOS chips.

[0072] Embodiment 5: A spectral sensing device according to any one of the preceding embodiments, wherein the at least one photosensitive detector, in particular the at least one photosensitive region, comprises at least one photoconductive material.

[0073] Embodiment 6: The spectral sensing device of the preceding embodiment, wherein the at least one photoconductive material is selected from at least one of PbS, PbSe, Ge, InGaAs, InSb, or HgCdTe.

[0074] Embodiment 7: A spectral sensing device according to any one of the preceding embodiments, wherein the emitted optical radiation comprises wavelengths between 760 nm and 1000 μm (infrared spectral range).

[0075] Embodiment 8: The spectral sensing device of the preceding embodiment, wherein the emitted optical radiation comprises wavelengths between 760 nm and 3 μm (near infrared spectral range).

[0076] Embodiment 9: The spectral sensing device of the preceding embodiment, wherein the emitted optical radiation comprises wavelengths between 1 μm and 3 μm.

[0077] Embodiment 10: A spectral sensing device according to any one of the preceding embodiments, wherein the evaluation unit is further designed to fully or partially control or drive the spectral sensing device or part thereof.

[0078] Embodiment 11: A spectral sensing device described in any one of the preceding embodiments, wherein the evaluation unit is further configured to control at least one of the at least one radiation emitting element and the at least one photosensitive detector.

[0079] Embodiment 12: A spectral sensing device described in any one of the preceding embodiments, wherein the at least one measurement information determined by the evaluation unit is provided to at least one further device or to a user in at least one of electronic, visual, acoustic or tactile manners.

[0080] Embodiment 13: A spectral sensing device according to any one of the preceding embodiments, wherein the at least one measurement information determined by the evaluation unit is stored in at least one data storage unit.

[0081] Embodiment 14: A spectral sensing device according to any preceding embodiment, wherein the at least one data storage unit is included by the spectral sensing device, in particular by the at least one evaluation unit.

[0082] Embodiment 15: A spectral sensing device according to any one of the preceding two embodiments, wherein the at least one data storage unit is a separate storage unit.

[0083] Embodiment 16: The spectral sensing device of any preceding embodiment, wherein the separate storage unit is included by at least one electronic communication unit.

[0084] Embodiment 17: A spectrum sensing device according to any one of the previous two embodiments, wherein the at least one measurement information is transmitted to the separate storage unit via at least one interface, in particular a wireless interface and / or a wired interface.

[0085] Embodiment 18: A spectral sensing device according to any one of the preceding embodiments, wherein the at least one measurement information relates to a responsivity of the at least one photosensitive detector.

[0086] Embodiment 19: A spectral sensing device as described in any one of the preceding embodiments, wherein the at least one measurement information comprises at least one of a change in resistance ΔR of the at least one photosensitive detector and a responsivity dependent quotient of the at least one photosensitive detector.

[0087] Embodiment 20: The at least one responsivity-dependent quotient is a function of the change in resistance ΔR of the at least one photosensitive detector relative to the DC resistance R of the at least one photosensitive detector. DC 4. The spectral sensing device of claim 1, wherein the spectral sensing device is defined as a quotient divided by

[0088] Embodiment 21: A spectral sensing device described in any one of the previous two embodiments, wherein the change in resistance ΔR of the at least one photosensitive detector is induced by superposition of optical radiation provided by at least one measurement object and modulated optical radiation emitted by the at least one radiation emitting element in the at least one photosensitive detector.

[0089] Embodiment 22: A spectral sensing device according to any one of the preceding embodiments, further comprising at least one readout circuit configured to read out the at least one photosensitive detector, in particular in a resistance measurement.

[0090] Embodiment 23: The readout circuitry detects the DC resistance R of the at least one photosensitive detector. DC and / or configured to measure a change in resistance ΔR of the at least one photosensitive detector.

[0091] Embodiment 24: A spectral sensing device as described in any one of the previous two embodiments, wherein the readout circuitry includes at least one of a resistance meter, a voltage divider, and a pass filter, and in particular includes a high-pass filter.

[0092] Embodiment 25: A spectral sensing device as described in any one of the preceding embodiments, wherein the at least one radiation emitting element is designated to emit modulated optical radiation such that the modulated optical radiation has a constant irradiance output.

[0093] Embodiment 26: A method for detecting a temperature difference between a sensor and a sensor array, comprising: - at least one photosensitive area of ​​the at least one first photosensitive detector is designated to receive modulated light radiation; at least one photosensitive area of ​​the at least one second photosensitive detector is designated to receive the optical radiation provided by the at least one measurement object and the modulated optical radiation; 13. A spectral sensing device as in any one of the preceding embodiments.

[0094] Embodiment 27: A spectral sensing device described in any one of the preceding two embodiments, further comprising at least one radiation separation element, the at least one radiation separation element being designed and arranged to separate modulated light radiation from the light radiation provided by the at least one measurement object.

[0095] Embodiment 28: The at least one radiation isolation element comprises at least one a first optical filter element, the at least one first optical filter element being designated and positioned such that the at least one photosensitive area of ​​the at least one first photosensitive detector receives only modulated optical radiation; 4. The spectral sensing device of claim 1, further comprising:

[0096] Embodiment 29: The at least one radiation isolation element comprises: at least one non-transmissive optical element, said at least one non-transmissive optical element comprising: such that at least one photosensitive area of ​​said at least one first photosensitive detector receives only modulated optical radiation; at least one non-transmissive optical element, designated and positioned; 13. The spectral sensing device of any one of the preceding two embodiments, comprising:

[0097] Embodiment 30: The optical radiation provided by the at least one measurement object is - emitted by said at least one measurement object; - reflected by said at least one measurement object; - transmitted through said at least one measurement object; 13. The spectral sensing device of any one of the preceding embodiments, wherein the spectral sensing device comprises at least one of:

[0098] Embodiment 31: at least one optical element configured to direct modulated light radiation towards said at least one photosensitive detector; 13. The spectral sensing device of any one of the preceding embodiments, further comprising:

[0099] Embodiment 32: A spectral sensing device as described in the preceding embodiment, wherein the at least one optical element comprises at least one partially reflective optical element designed to reflect modulated light radiation emitted by the at least one radiation-emitting element towards the at least one photosensitive detector.

[0100] Embodiment 33: A spectral sensing device as described in the preceding embodiment, wherein the at least one partially reflective optical element is transparent to optical radiation provided by the at least one measurement object.

[0101] Embodiment 34: - at least one further radiation-emitting element, said at least one further radiation-emitting element being designed to emit a further modulated light radiation; The at least one evaluation unit at least one modulated detector signal generated by illumination of at least one light-sensitive area by superposition of the optical radiation provided by the at least one measurement object and the further modulated optical radiation; and At least one measurement; at least one further radiation-emitting element, further configured to generate at least one spectral information about the at least one measurement object by using Further equipped with 13. The spectral sensing device of any one of the preceding embodiments, wherein the spectral sensing device is positioned such that the further modulated light radiation is directed towards the at least one measurement object.

[0102]

[0036] Embodiment 35: The at least one evaluation unit further comprises: generating at least one calibration information by comparing at least one modulated detector signal generated by illumination of the at least one photosensitive area with modulated light radiation and at least one further modulated detector signal generated by illumination of the at least one photosensitive area with further modulated light radiation; 4. A spectral sensing device as in any preceding embodiment, configured

[0103] Embodiment 36: A spectral sensing device described in any one of the preceding two embodiments, wherein the at least one further radiation emitting element is designated to emit the further modulated optical radiation such that the further modulated optical radiation has a constant irradiance output.

[0104] Embodiment 37: A spectral sensing device described in any one of the preceding three embodiments, wherein the spectral sensing device is positioned such that the further modulated optical radiation is reflected by the at least one measurement object.

[0105] Embodiment 38: A method for detecting a temperature difference between a sensor and a detector, comprising: - at least one photosensitive area of ​​at least one further first photosensitive detector is designated to receive said modulated light radiation; and at least one light-sensitive area of ​​at least one further second light-sensitive detector is designated to receive said further modulated light radiation and said light radiation provided by said at least one measurement object; 13. A spectral sensing device as in any one of the preceding four embodiments.

[0106] Embodiment 39: A spectral sensing device as described in the preceding embodiment, further comprising at least one further radiation separation element, the at least one further radiation separation element designed and arranged to separate the modulated light radiation from the further modulated light radiation.

[0107] Embodiment 40: The at least one further radiation isolation element comprises: - at least one further first optical filter element, said at least one further first optical filter element being designed and arranged such that at least one photosensitive area of ​​said at least one further first photosensitive detector receives only said modulated optical radiation; at least one further second optical filter element, which is designed and arranged such that at least one photosensitive area of ​​the at least one further second photosensitive detector receives only the further modulated optical radiation and the optical radiation provided by the at least one measurement object; 4. The spectral sensing device of claim 1, further comprising:

[0108] Embodiment 41: The at least one further radiation isolation element comprises: at least one further non-transmissive optical element, said at least one further non-transmissive optical element comprising the at least one photosensitive area of ​​the at least one further first photosensitive detector receives only modulated light radiation, and at least one photosensitive area of ​​the at least one further second photosensitive detector receives only the further modulated light radiation and the light radiation provided by the at least one measurement object, at least one further non-transmissive optical element, 13. The spectral sensing device of any one of the preceding two embodiments, further comprising:

[0109]

[0081] Embodiment 42: The at least two separate photosensitive detectors include: - at least one photosensitive area of ​​said at least one further first photosensitive detector receives only said modulated light radiation; and at least one light-sensitive area of ​​the at least one further second light-sensitive detector receives the modulated light radiation, the further modulated light radiation and light radiation provided by the at least one measurement object, 3. A spectral sensing device as in any one of the preceding three embodiments, arranged so that

[0110] Embodiment 43: A method for detecting a radiation image comprising the at least two additional first individual photosensitive detectors, - at least one photosensitive area of ​​one of the at least two further first photosensitive detectors receives only the modulated light radiation; and at least one photosensitive area of ​​another one of the at least two further first photosensitive detectors receives the modulated light radiation and the light radiation provided by the at least one measurement object, 13. The spectral sensing device of any preceding embodiment.

[0111] Embodiment 44: at least one further partially reflective optical element, which is designed to reflect modulated light radiation emitted by the at least one radiation emitting element towards the at least one photosensitive detector and to transmit further light radiation emitted by the at least one further emitting element towards the at least one measurement object, 10. The spectral sensing device of any one of the preceding embodiments, further comprising:

[0112] Embodiment 45: A spectral sensing device as described in the preceding embodiment, wherein the at least one further partially reflective optical element is transparent to optical radiation provided by the measurement object.

[0113] Embodiment 46: at least one temperature stabilizing element, said at least one temperature stabilizing element comprising: said at least one photosensitive detector; said at least one radiation-emitting element; at least one temperature stabilizing element designated to maintain the temperature of at least one of the 13. The spectral sensing device of any one of the preceding embodiments, further comprising:

[0114] Embodiment 47: A spectral sensing device as described in the preceding embodiment, wherein the at least one temperature stabilizing element is optionally designated to maintain the temperature of the at least one further radiation-emitting element at a constant level.

[0115] Embodiment 48: A method for measuring optical radiation provided by at least one measurement object, wherein the optical radiation provided by the at least one measurement object comprises non-modulated optical radiation, the method comprising the following steps: a) emitting modulated optical radiation by using at least one radiation emitting element, said modulated optical radiation being directed towards at least one photosensitive detector within a spectral sensing device, said at least one photosensitive detector having at least one photosensitive area designated to receive optical radiation, and at least one detector signal generated by said at least one photosensitive detector being dependent on illumination of said at least one photosensitive area; b) generating, by means of the at least one evaluation unit, at least one measurement information regarding the illumination of the at least one light-sensitive area by the light radiation provided by the at least one measurement object, by means of at least one detector signal generated by illumination of the at least one light-sensitive area by means of a superposition of the modulated light radiation and the light radiation provided by the at least one measurement object; A method comprising:

[0116] Embodiment 49: c) emitting a further modulated light radiation by using at least one further radiation emitting element, said further modulated light radiation being directed towards said at least one measurement object; d) generating at least one spectral information about the at least one measurement object, at least one modulated detector signal generated by illumination of the at least one light-sensitive area by superposition of the optical radiation provided by the at least one measurement object and the further modulated optical radiation; said at least one measurement information; generating at least one spectral information about the at least one measurement object by using the at least one evaluation unit; 4. The method of claim 1, further comprising:

[0117] Embodiment 50: e) generating at least one calibration information by using said at least one evaluation unit by further comparing at least one detector signal generated by illumination of said at least one photosensitive area with said modulated light radiation and at least one further detector signal generated by illumination of said at least one photosensitive area with said further modulated light radiation, 20. The method of any one of the preceding embodiments relating to a method, comprising:

[0118]

[0046] Embodiment 51: The at least one calibration information - a modulated light radiation and a further modulated light radiation differing by at least one modulation frequency; at least one first photosensitive region and at least one second photosensitive region differing by at least one spectral sensitivity; 4. The method of claim 1, wherein the at least one detector signal is generated by distinguishing the at least one detector signal from the at least one further detector signal by using at least one of:

[0119] Embodiment 52: A computer program comprising instructions which, when the program is executed by a computer, cause the computer to carry out steps of a method for measuring optical radiation.

[0120] Embodiment 53: Use of a spectral sensing device according to any one of the preceding embodiments, referring to the spectral sensing device or the method for measuring optical radiation, for a use selected from the group consisting of: infrared detection applications; spectroscopy applications; exhaust gas monitoring applications; combustion process monitoring applications; pollution monitoring applications; industrial process monitoring applications; mixing or blending process monitoring; chemical process monitoring applications; food treatment process monitoring applications; food preparation process monitoring; water quality monitoring applications; air quality monitoring applications; quality control applications; temperature control applications; motion control applications; exhaust control applications; gas detection applications; gas analysis applications; motion sensing applications; chemical sensing applications; mobile applications; medical applications; mobile spectroscopy applications; food analysis applications; in particular agricultural applications such as soil, silage, feed, crop or produce characterization, plant health monitoring; plastic identification and / or recycling applications. [Brief description of the drawings]

[0121] Further optional details and features of the invention are evident from the following description of preferred exemplary embodiments in conjunction with the dependent claims. In this context, certain features may be implemented alone or in combination with other features. The invention is not limited to the exemplary embodiments. The exemplary embodiments are illustrated diagrammatically in the figures. Identical references in the individual figures refer to identical elements or elements with identical functions or elements which correspond to each other in terms of their functions.

[0122] Specifically, in the following diagram: [Figure 1]1 shows a schematic diagram of an exemplary embodiment of a spectral sensing device; [Diagram 2] 1 shows a schematic diagram of an exemplary embodiment of a spectral sensing device; [Diagram 3] 1 shows a schematic diagram of an exemplary embodiment of a spectral sensing device; [Figure 4] 1 shows a schematic diagram of an exemplary embodiment of a spectral sensing device; [Diagram 5] 1 shows a schematic diagram of an exemplary embodiment of a spectral sensing device; [Figure 6] 1 shows a schematic diagram illustrating an exemplary embodiment of a method for measuring optical radiation according to the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0123] Exemplary embodiments 1 to 5C each show, in a highly schematic manner, an exemplary embodiment of a spectral sensing device 110 according to the invention. The spectral sensing device 110 is configured to measure optical radiation 112 provided by at least one measurement object 114. The optical radiation 112 provided by the at least one measurement object 114 comprises unmodulated optical radiation 116. The optical radiation 112 may comprise at least one of the visible, ultraviolet and infrared spectral ranges of electromagnetic radiation. According to the invention, the spectral sensing device 110 may be adapted in particular to record spectra for the infrared (IR) spectral region, preferably the near infrared (NIR), in particular for wavelengths between 760 nm and 3 μm, preferably between 1 μm and 3 μm. Thus, the spectral sensing device 110 can be used for heat, flame, fire or smoke detection, as well as for research or monitoring purposes.

[0124] In particular, the measurement object 114 may comprise at least one thermal radiator, e.g. a metal plate on a heater, that emits unmodulated optical radiation according to Planck's law. In such a case, the spectral sensing device 110 for measuring optical radiation may be used, in particular, to determine the temperature of the at least one measurement object 114. As an example going in this direction, the at least one measurement object 114 may include at least one cookware, and the at least one cookware may be placed on a countertop. In such a case, in particular, it may be desired to measure at least one temperature of the at least one measurement object 114, which may be derived from the emissivity of the at least one measurement object 114, as will be appreciated by those skilled in the art. However, further applications of the spectral sensing device 110 are also possible. Thus, the optical radiation 112 provided by the at least one measurement object 114 may in particular be emitted by the at least one measurement object 114. Additionally and / or alternatively, however, the optical radiation 112 provided by the at least one measurement object may also be reflected by and / or transmitted through the at least one measurement object 114. In particular, the at least one measurement object 114 may be illuminated by at least one external light source (not shown here).

[0125] The spectral sensing device 110 comprises at least one radiation-emitting element 118. The radiation-emitting element 118 is designed to emit modulated optical radiation 120. In particular, the radiation-emitting element 118 may be preferably comprised by a semiconductor-based radiation source 122, which may be selected from at least one of a light-emitting diode (LED) or a laser, in particular a laser diode. However, further types of radiation-emitting element 118 are also possible, such as a thermal emitter (not shown here). The radiation-emitting element 118 may emit continuously or generate modulated optical pulses, as described in more detail above. The radiation-emitting element 118 may be designed to emit the modulated optical radiation 120 such that the modulated optical radiation 120 has a constant irradiance power.

[0126] The spectral sensing device 110 comprises at least one photosensitive detector 124. The photosensitive detector 124 has at least one photosensitive area 126 designated to receive the optical radiation 112. At least one detector signal generated by the at least one photosensitive detector 124 depends on the illumination of the at least one photosensitive area 124. The at least one photosensitive detector 124 can be selected from any known light sensor, in particular from inorganic camera elements, preferably from inorganic camera chips, more preferably from CCD chips or CMOS chips. The alternative photosensitive area 126 preferably comprises at least one photoconductive material, in particular selected from lead sulfide (PbS), lead selenide (PbSe), germanium (Ge), indium gallium arsenide (InGaAs, including but not limited to extended InGaAs), indium antimonide (InSb) or mercury cadmium telluride (HgCdTe or MCT). However, further types of photoconductive materials or other types of photosensitive detectors are also possible.

[0127] The spectral sensing device 110 comprises at least one evaluation unit 128. The evaluation unit 128 is configured to generate at least one measurement information regarding the illumination of the at least one photosensitive region 126 by the optical radiation 112 provided by the at least one measurement object 114 by using at least one modulated detector signal generated by illumination of the at least one photosensitive region 126 by superposition of the modulated optical radiation 120 and the optical radiation 112 provided by the at least one measurement object 114.

[0128] Furthermore, the evaluation unit may comprise at least one interface, in particular at least one of a wireless interface or a wired interface to one or more elements of the sensing device 110. Furthermore, the evaluation unit 128 may be designed to fully or partially control or drive one or more of the other elements of the spectral sensing device 110. The evaluation unit 128 may be configured to control at least one of the radiation emitting elements 118 and the photosensitive detector 124. The evaluation unit 128 may be designed in particular to perform at least one measurement cycle in which a number of detector signals may be picked up. The information determined by the evaluation unit 128 may in particular be provided to at least one further device or to a user, preferably in at least one of electronic, visual, acoustic or tactile manner. Furthermore, the information may be stored in at least one data storage unit (not shown here), in particular an internal data storage unit included by the spectral sensing device 110, in particular an internal data storage unit included by the at least one evaluation unit 128, or in a separate storage unit that may be included by the communication unit (not shown here). At least one of the spectral information or the measurement information can be transmitted via at least one interface, in particular a wireless interface and / or a wired interface, to a separate storage unit, which may in particular be configured to store at least one electronic table, such as at least one look-up table.

[0129] The at least one measurement information generated by the evaluation unit 128 may relate to the responsivity of the photosensitive detector 124. In particular, the at least one measurement information may include at least one of a change in resistance ΔR of the photosensitive detector 124 and a responsivity-dependent quotient of the photosensitive detector 124. The at least one responsivity-dependent quotient may be calculated by dividing the change in resistance ΔR of the photosensitive detector 124 by the DC resistance R of the photosensitive detector 124. DCThe change in resistance ΔR of the photosensitive detector 124 can be defined as the quotient divided by the light radiation 112 provided by the measurement object 114. The change in resistance ΔR of the photosensitive detector 124 can be induced by the superposition of the light radiation 112 provided by the measurement object 114 and the modulated light radiation 120 emitted by the radiation-emitting element 118 at the photosensitive detector 124. As shown in FIG. 1, the optical path of the light radiation 112 provided by the measurement object 114 can cross the optical path of the modulated light radiation 120 emitted by the radiation-emitting element 118 at the photosensitive detector 124. Thus, the light radiation 112 provided by the measurement object 114 can interfere with the modulated light radiation 120 emitted by the radiation-emitting element 118 before being detected by the photosensitive detector 124.

[0130] The spectral sensing device 110 may further comprise at least one readout circuit. The readout circuit may be configured specifically for resistive measurement to read out the photosensitive detector 124. The readout circuit may be configured to read out the DC resistance R DC and / or may be configured to measure a change in resistance ΔR of the photosensitive detector 124. The readout circuit may comprise at least one of an ohmmeter, a voltage divider, and a pass filter, in particular a high-pass filter (not shown here).

[0131] The spectral sensing device 110 is arranged such that the modulated light radiation is guided within the spectral sensing device 110 towards at least one photosensitive detector 124. The spectral sensing device 110 may comprise at least one optical element 130 configured to guide the modulated light radiation 120 towards the at least one photosensitive detector 124. The optical element 130 may comprise at least one partially reflective optical element 132. The at least one partially reflective optical element 132 may be designed to reflect the modulated light radiation 120 emitted by the at least one radiation emitting element 118 towards the at least one photosensitive detector 124. The at least one partially reflective optical element 132 may be transparent to the light radiation 112 provided by the at least one measurement object 114. Thus, the light radiation 112 provided by the at least one measurement object 114 may be transmitted through the at least one partially reflective optical element 132, specifically towards the at least one photosensitive detector 124.

[0132] As shown in FIG. 1, the radiation-emitting element 118 may be arranged laterally offset with respect to the photosensitive detector 124. The measurement object 114 may be arranged in front of the spectral sensing device 110. The spectral sensing device 110 may comprise at least one housing 134. The housing 134 may at least partially enclose further components of the spectral sensing device 110. The housing 134 may thus particularly shield the highly sensitive components of the spectral sensing device 110 from environmental influences. The partially reflective optical element 132 may be enclosed in the housing 134 and may be arranged on a side of the housing 134 facing the measurement object 114. In this arrangement, the modulated optical radiation 120 emitted by the radiation-emitting element 118 may be directed to the partially reflective optical element 132. The partially reflective optical element 132 may then reflect the modulated optical radiation 120 emitted by the radiation-emitting element 118 towards the photosensitive detector 124. At the same time, the optical radiation 112 provided by the measurement object 114 may enter the spectral sensing device 110 through the partially reflective optical element 132 and interfere with the modulated optical radiation 120 emitted by the radiation emitting element 118 within the spectral sensing device 110 before being detected by the photosensitive detector 124.

[0133] In a preferred embodiment, as shown in Fig. 2, the spectral sensing device 110 may further comprise at least one further radiation-emitting element 136. The further radiation-emitting element 136 may be designed to emit a further modulated light radiation 138. The further radiation-emitting element 136 may also be arranged laterally offset with respect to the photosensitive detector 124, specifically on the opposite side to the radiation-emitting element 118. The further radiation-emitting element 136 may be designed to emit the further modulated light radiation 138, such that the further modulated light radiation 138 has a constant irradiance output. Specifically, the further radiation-emitting element 136 may be structurally identical to the at least one radiation-emitting element 118, or may have at least similar characteristics, specifically emission characteristics such as irradiance output and / or wavelength range. Therefore, for further details regarding the further radiation-emitting element 136, reference may be made to the description of the at least one radiation-emitting element 118 provided above.

[0134] The evaluation unit 128 may further be configured to generate at least one spectral information on the at least one measurement object 114 by using the at least one modulated detector signal generated by illumination of the at least one photosensitive region 126 by the optical radiation 112 provided by the at least one measurement object 114, further the modulated optical radiation 138 and the at least one measurement information. The evaluation unit 128 may further be configured to generate at least one calibration information by further comparing the at least one modulated detector signal generated by illumination of the at least one photosensitive region 126 by the modulated optical radiation 120 with at least one further modulated detector signal generated by illumination of the at least one photosensitive region 126 by the further modulated optical radiation 138.

[0135] The spectral sensing device 110 may be arranged such that the further modulated light radiation 138 can be directed towards the measurement object 114. Furthermore, the spectral sensing device 110 may be arranged such that the further modulated light radiation 138 can be reflected by the measurement object 114, in particular towards the photosensitive detector 124. As FIG. 2 shows, the further modulated light radiation 138 may be transmitted through the partially reflective optical element 132. Thus, the partially reflective optical element 132 may be designated to transmit the further light radiation 138 emitted by the at least one further emitting element 136 towards the at least one measurement object 114. The further light radiation 138 emitted by the at least one further emitting element 136 may then be scattered at the measurement object 114 and in particular at least partially reflected towards the photosensitive detector 124. Before impinging on the photosensitive detector 124, the further modulated optical radiation 138 passes through the partially reflective optical element 132 into the spectral sensing device 110 and may interfere with the modulated optical radiation 120 emitted by the radiation emitting element 118 and / or the optical radiation 112 provided by the measurement object 114.

[0136] The spectral sensing device 110 may further comprise at least one temperature stabilizing element 140. The temperature stabilizing element 140 may be designated to maintain the temperature of at least one of the photosensitive detector 124, the radiation-emitting element 118 and the further radiation-emitting element 136 at a constant level. This may in particular facilitate the avoidance of drift effects during the measurement. The temperature stabilizing element 140 may in particular comprise at least one thermoelectric cooler 142. As FIG. 2 shows, the radiation-emitting element 118, the photosensitive detector 124 and the further radiation-emitting element 136 may be arranged side by side on the temperature stabilizing element 140 and may therefore be stabilized simultaneously.

[0137] 3 shows, the temperature stabilizing element 140 can alternatively stabilize only the photosensitive detector 124. As a result, the radiation-emitting element 118 and / or the further radiation-emitting element 136 do not have to be disposed on the temperature stabilizing element 140. As a result, the arrangement of the radiation-emitting element 118 and / or the further radiation-emitting element 136 can be more flexible. In particular, the radiation-emitting element 118 may be disposed such that it can directly irradiate the photosensitive detector 124.

[0138] 4A and 4B show an exemplary embodiment of a spectral sensing device 110 including at least two individual photosensitive detectors 124. At least one of the individual photosensitive detectors 124 may be arranged on a temperature stabilization element 140 for temperature stabilization. The photosensitive area 126 of at least one first photosensitive detector 144 may be designated to receive the modulated light radiation 120. The photosensitive area 126 of at least one second photosensitive detector 146 may be designated to receive the light radiation 112 provided by at least one measurement object 114 and the modulated light radiation 120. The photosensitive area 126 of the second photosensitive detector 146 may further be designated to additionally receive the further modulated light radiation 138 emitted by the further radiation emitting element 136. The spectral sensing device 110 may further comprise at least one radiation separation element 148. The radiation separation element 148 may be specifically designed and arranged to separate the modulated optical radiation 120 emitted by the radiation-emitting element 118 from the further optical radiation 138 emitted by the further radiation-emitting element 136 .

[0139] 4A shows, the radiation separation element 148 may comprise at least one non-transmissive optical element 150. The non-transmissive optical element 150 may be designated and arranged such that the light-sensitive area 126 of the first light-sensitive detector 144 receives only the modulated optical radiation 120 emitted by the radiation-emitting element 118 and the light-sensitive area 126 of the second light-sensitive detector 146 receives only the further modulated optical radiation 138 emitted by the further radiation-emitting element 136. The non-transmissive optical element 150 may further be designated and arranged such that the light-sensitive area 126 of the first light-sensitive detector 144 and / or the light-sensitive area 126 of the second light-sensitive detector 146 additionally or alternatively receives the optical radiation 112 provided by the measurement object 114.

[0140] 4B shows, the radiation separation element 148 may comprise at least one of at least one first optical filter element 152 and at least one second optical filter element 154. The first optical filter element 152 may be designed and arranged such that the photosensitive area 126 of the first photosensitive detector 144 can only receive the modulated optical radiation 120 emitted by the radiation-emitting element 118. The first optical filter element 152 may further be designed and arranged such that the photosensitive area 126 of the first photosensitive detector 144 can additionally or alternatively receive the optical radiation 112 provided by the measurement object 114. The second optical filter element 154 may be designed and arranged such that the photosensitive area 126 of the second photosensitive detector 146 can receive the further modulated optical radiation 138 emitted by the further radiation-emitting element 136. The second optical filter element 154 may further be designed and positioned such that the photosensitive area 126 of the second photosensitive detector 146 additionally or alternatively receives the optical radiation 112 provided by the measurement object 114 .

[0141] 5A-5C show an exemplary embodiment of a spectral sensing device 110 comprising multiple photosensitive detectors 124 arranged such that at least one of the photosensitive detectors 124 is unable to receive optical radiation 112 provided by the measurement object 114.

[0142] As shown in Fig. 5A, the spectral sensing device 110 may comprise two separate photosensitive detectors 124 arranged such that the photosensitive area 126 of the first photosensitive detector 144 can only receive the modulated light radiation 120 and the photosensitive area 126 of the second photosensitive detector 146 can only receive the further modulated light radiation 138 and the light radiation 112 provided by the at least one measurement object 114. For this purpose, the partially reflective optical element 132 may extend only in front of the second photosensitive detector 146. Thus, the light radiation 112 provided by the at least one measurement object 114 passing through the partially reflective optical element 132 can only reach the second photosensitive detector 146. Furthermore, the first photosensitive detector 144 and the second photosensitive detector 146 may be separated by a radiation separation element 148, in particular by a non-transparent optical element 150. The non-transmissive optical element 150 may in particular ensure that the first photosensitive detector 144 cannot receive further modulated optical radiation 120 and / or optical radiation provided by the measurement object 114 .

[0143] Furthermore, the exemplary embodiment of the spectral sensing device 110 as shown in Fig. 5A may comprise a second radiation-emitting element 156, which may also emit the modulated optical radiation 120. The second radiation-emitting element 156 may specifically emit the modulated optical radiation 120 towards the second photosensitive detector 146. Thus, the second photosensitive detector 146 may additionally receive the modulated optical radiation 120. As shown in Fig. 5B, the photosensitive detector 124 may alternatively be positioned such that the second photosensitive detector 146 may also receive the modulated optical radiation 120 emitted by the radiation-emitting element 118.

[0144] As shown in Fig. 5C, the spectral sensing device 110 may comprise at least a third photosensitive detector 158. The photosensitive area 126 of the third photosensitive detector 158 may receive only the modulated light radiation 120 and the light radiation 114 provided by the measurement object 114. The modulated light radiation 120 may specifically only reach the first photosensitive detector 144 and the third photosensitive detector 156, but may no longer reach the second photosensitive detector 146. Thus, the second photosensitive detector 146 may only receive the further modulated light radiation 138 and the light radiation 112 provided by the measurement object 114. As Fig. 5C shows, a radiation separation element 148, specifically a non-transmitting optical element 150, may be arranged between the second photosensitive detector 146 and the third photosensitive detector 156 to prevent the modulated light radiation 120 from reaching the second photosensitive detector 146. The partially reflective optical element 132 can only extend in front of the second photosensitive detector 146 and the third photosensitive detector 156. Thus, the optical radiation 112 provided by the at least one measurement object 114 passing through the partially reflective optical element 132 can only reach the second photosensitive detector 146 and the third photosensitive detector 156.

[0145] FIG. 6 shows a schematic diagram of an exemplary embodiment of a method for measuring optical radiation 112 provided by a measurement object 114 according to the present invention.

[0146] In an emission step 160 according to step a), the modulated optical radiation 120 is emitted by using the emission element 118. The modulated optical radiation is directed towards the photosensitive detector 124 within the spectral sensing device 110. In particular, the modulated optical radiation 120 can be reflected towards the photosensitive detector 124 at the partially reflective optical element 132.

[0147] In the measurement information generation step 162 according to step b), at least one measurement information regarding the irradiation of at least one photosensitive area 126 by the optical radiation 112 provided by the at least one measurement object 114 is generated by using the evaluation unit 128 by using at least one modulated detector signal generated by the irradiation of the photosensitive area 126 by the superposition of the modulated optical radiation 120 and the optical radiation 112 provided by the at least one measurement object 114.

[0148] In an optional further emission step 164 according to step c), the further modulated light radiation 138 may be emitted by using the further radiation emitting element 136. The further modulated light radiation 138 may be directed towards the measurement object 114. In particular, the further modulated light radiation 138 may be transmitted through the optical element 130, more particularly through the partially reflective optical element 132, towards the measurement object 114. The further modulated light radiation 138 may then be at least partially reflected by the measurement object 114 towards the photosensitive detector 124.

[0149] In an optional spectral information generation step 166 according to step d), at least one spectral information regarding the at least one measurement object 114 may be generated by using at least one modulated detector signal generated by illumination of one photosensitive region 126 by the optical radiation 112 provided by the measurement object 114, further the modulated optical radiation 138, and the at least one measurement information. In particular, the optical radiation 112 provided by the measurement object 114 may be transmitted through the optical element 130, more particularly the partially reflective optical element 132, before reaching the photosensitive region 126.

[0150] In an optional calibration information generation step 168 according to step e), at least one calibration information can be generated using at least one evaluation unit 128 by further comparing at least one detector signal generated by irradiation of at least one photosensitive area 126 by modulated optical radiation 120 with at least one further detector signal generated by irradiation of at least one photosensitive area 126 by further modulated optical radiation 138.

[0151] As already indicated above, the emission step 160 and the further emission step 164 may in particular be performed simultaneously. Accordingly, the measurement information generation step 162 and the calibration information generation step 168 can also in particular be performed simultaneously. Thus, the results obtained in the measurement information generation step 162 and / or the calibration information generation step 168 can in particular be used in the final spectral information generation step 166 in the same time.

[0152] For further details regarding how to measure the optical radiation 112, please refer to the description of the spectral sensing device 110 provided above. [Explanation of symbols]

[0153] 110 Spectral Sensing Device 112 Photon Radiation 114 Measuring object 116 Non-modulated optical radiation 118 Radiation-emitting element 120 Modulated Light Radiation 122 Semiconductor-based radiation sources 124 Photosensitive element 126 Photosensitive area 128 evaluation units 130 Optical Elements 132 Partially Reflecting Optical Elements 134 Housing 136 Further radiation-emitting elements 138 Further Modulated Light Radiation 140 Temperature stabilization element 142 Thermoelectric cooler 144 Photosensitive Detector 146 Second Photosensitive Detector 148 Radiation Isolation Elements 150 Non-transparent optical elements 152 first optical filter element 154 Second Optical Filter Element 156 Second Radiation Emitting Element 158 Third Photosensitive Detector 160 Release Steps 162 Measurement information generation step 164 Further Release Steps 166 Spectral information generation step 168 Calibration information generation step

Claims

1. A spectral sensing device (110) for measuring optical radiation (112) provided by at least one measurement object (114), the optical radiation (112) provided by the at least one measurement object (114) including unmodulated optical radiation (116), the spectral sensing device (110) comprising: at least one radiation-emitting element (118), said at least one radiation-emitting element (118) being designed to emit modulated optical radiation (120); at least one photosensitive detector (124), said at least one photosensitive detector (124) having at least one photosensitive area (126) designated to receive the optical radiation (112), and at least one detector signal generated by said at least one photosensitive detector (124) depending on the illumination of said at least one photosensitive area (126); at least one evaluation unit (128) configured to generate at least one measurement information regarding the illumination of the at least one photosensitive area (126) by the optical radiation (112) provided by the at least one measurement object (114) by using at least one modulated detector signal generated by illumination of the at least one photosensitive area (126) by superposition of the modulated optical radiation (120) and the optical radiation (112) provided by the at least one measurement object (114), The spectral sensing device (110) is positioned such that modulated optical radiation (120) is directed within the spectral sensing device (110) toward the at least one photosensitive detector (124).

2. 2. The spectral sensing device (110) of claim 1, wherein the at least one measurement information relates to a responsivity of the at least one photosensitive detector (124).

3. 3. The spectral sensing device (110) of claim 1 or 2, wherein the at least one measurement information comprises at least one of a change in resistance ΔR of the at least one photosensitive detector (124) and a responsivity-dependent quotient of the at least one photosensitive detector (124).

4. The at least one responsivity-dependent quotient is a ratio of the change in resistance ΔR of the at least one photosensitive detector (124) to the DC resistance R of the at least one photosensitive detector (124). DC 4. The spectral sensing device (110) of claim 3, wherein the spectral sensing element (110) is defined as a quotient of .lamda. / .lamda.

5. 4. The spectral sensing device (110) of claim 3, wherein the change in resistance ΔR of the at least one photosensitive detector (124) is induced by the superposition of optical radiation (112) provided by the at least one measurement object (114) and modulated optical radiation (120) emitted by the at least one radiation-emitting element (118) in the at least one photosensitive detector (124).

6. 3. The spectral sensing device (110) of claim 1 or 2, wherein the at least one radiation emitting element (118) is designated to emit the modulated optical radiation (120) such that the modulated optical radiation (120) has a constant irradiance output.

7. at least two individual photosensitive detectors (124); at least one photosensitive area (126) of at least one first photosensitive detector (144) is designated to receive the modulated optical radiation (120); at least one photosensitive area (126) of at least one second photosensitive detector (146) is designated to receive the optical radiation (112) and the modulated optical radiation (120) provided by the at least one measurement object (114); A spectral sensing device (110) according to claim 1 or 2.

8. 8. The spectral sensing device (110) of claim 7, further comprising at least one radiation separation element (148), the at least one radiation separation element (148) being designed and positioned to separate the modulated optical radiation (120) from the optical radiation (112) provided by the at least one measurement object (114).

9. The at least one radiation isolation element (148) comprises at least one a first optical filter element (152), said at least one first optical filter element (152) being designated and arranged so that said at least one photosensitive area (126) of said at least one first photosensitive detector (144) receives only said modulated optical radiation (120); The spectral sensing device (110) of claim 8, comprising:

10. The at least one radiation isolation element (148) comprises: at least one non-transmissive optical element (150), said at least one non-transmissive optical element (150) being designated and arranged such that at least one photosensitive area (126) of said at least one first photosensitive detector (144) receives only said modulated optical radiation (120); The spectral sensing device (110) of claim 8, comprising:

11. The spectral sensing device (110) at least one further radiation-emitting element (136), said at least one further radiation-emitting element (136) being designed to emit a further modulated light radiation (138); The at least one evaluation unit (128) at least one modulated detector signal generated by illumination of the at least one photosensitive region (126) by superposition of the optical radiation (112) provided by the at least one measurement object (114) and the further modulated optical radiation (138); and at least one measurement; a radiation-emitting element (136) further configured to generate at least one spectral piece of information about the at least one measurement object (114) by using Further preparation, 3. The spectral sensing device (110) of claim 1 or 2, wherein the spectral sensing device (110) is positioned such that the further modulated optical radiation (138) is directed towards the at least one measurement object (114).

12. The at least one evaluation unit (128) further comprises:

12. The spectral sensing device (110) of claim 11, configured to generate at least one calibration information by comparing at least one modulated detector signal generated by irradiating the at least one photosensitive region (126) with the modulated optical radiation (120) with at least one further modulated detector signal generated by irradiating the at least one photosensitive region (126) with the further modulated optical radiation (138).

13. 12. The spectral sensing device (110) of claim 11, wherein the at least one further radiation emitting element (136) is designated to emit the further modulated optical radiation (138) such that the further modulated optical radiation (138) has a constant irradiance output.

14. The spectral sensing device (110) of claim 11, wherein the spectral sensing device (110) is positioned such that the further modulated optical radiation (138) is reflected by the at least one measurement object (114).

15. at least two individual photosensitive detectors (124); at least one photosensitive area (126) of at least one further first photosensitive detector (144) is designated to receive said modulated light radiation (120); and at least one photosensitive area of ​​at least one further second photosensitive detector (146) is designated to receive said further modulated light radiation (138) and said light radiation (112) provided by said at least one measurement object (114); The spectral sensing device (110) of claim 11.

16. at least one temperature stabilization element (140), said at least one temperature stabilization element (140) comprising: said at least one photosensitive detector (124); said at least one radiation-emitting element (118); at least one temperature stabilization element (140) designated to maintain at a constant level the temperature of at least one of The spectral sensing device (110) of claim 1 or 2 further comprising:

17. A method for measuring optical radiation (112) provided by at least one measurement object (114), wherein the optical radiation (112) provided by the at least one measurement object (114) comprises unmodulated optical radiation (116), the method comprising the steps of: a) emitting modulated optical radiation (120) by using at least one radiation-emitting element (118), the modulated optical radiation (120) being directed towards at least one photosensitive detector (124) within the spectral sensing device (110), the at least one photosensitive detector (124) having at least one photosensitive region (126) designated to receive the optical radiation (112), and at least one detector signal generated by the at least one photosensitive detector (124) depending on illumination of the at least one photosensitive region (126); b) generating, by means of at least one evaluation unit (128), at least one measurement information regarding the illumination of the at least one photosensitive area (126) by the optical radiation (112) provided by the at least one measurement object (114), by using at least one detector signal generated by the illumination of the at least one photosensitive area (126) by the superposition of the modulated optical radiation (120) and the optical radiation (112) provided by the at least one measurement object (114), Steps and A method comprising:

18. Further steps: c) emitting further modulated light radiation (138) by using at least one further radiation-emitting element (136), wherein said further modulated light radiation (138) is directed towards said at least one measurement object (114); d) generating at least one spectral information about the at least one measurement object (114), at least one modulated detector signal generated by illumination of the at least one photosensitive area (126) by superposition of the optical radiation (112) provided by the at least one measurement object (114) and the further modulated optical radiation (138); said at least one measurement; generating at least one spectral information about the at least one measurement object (114) by using the at least one evaluation unit (128); 18. The method of claim 17, comprising:

19. Further steps: e) generating at least one calibration information by using said at least one evaluation unit (128) by further comparing at least one detector signal generated by illumination of said at least one photosensitive area (126) by said modulated optical radiation (120) with at least one further detector signal generated by illumination of said at least one photosensitive area (126) by said further modulated optical radiation (138); 19. The method of claim 17 or 18, comprising:

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