Plant or in-situ calibration of thermoelectric and thermo-optical properties

Abstract

The invention relates to a method of operating a spectrometer device (110) for obtaining spectroscopy information about at least one object (112), the method comprising in particular evaluating a detector (128) signal by using at least one evaluation unit (136) of the spectrometer device (110), thereby obtaining spectroscopy information about the object (112) therefrom, the evaluation unit (136) is configured for selecting at least one correction information item from a predetermined set of correction information items as a function of an actual value of at least one operating parameter, and for taking into account the selected correction information item to obtain spectroscopy information. The invention further relates to a calibration method for compiling a set of correction information items, a spectrometer device (110) for obtaining spectroscopy information about at least one object (112), a computer program, a computer readable storage medium and a non-transitory computer readable medium. The invention has the advantage that the operating parameters can provide reliable correction parameters, especially under the condition that the ambient temperature is considered. As a result, fluctuations in the spectral flux of the at least one light source (114) and / or fluctuations in the spectral characteristic of the at least one light source (114), in particular deviations, can be compensated.

Description

Technical Field

[0001] The present invention relates to a method of operating a spectrometer device for obtaining spectroscopic information about at least one object, a calibration method for compiling a set of correction information items, and a spectrometer device for obtaining spectroscopic information about at least one object. The present invention further relates to a computer program, a computer-readable storage medium, and a non-transitory computer-readable medium.

[0002] In general, such methods and devices can be used for research or monitoring purposes, in particular in the infrared (IR) spectral region, in particular in the near-infrared (NIR) spectral region, and in the visible (VIS) spectral region, for example in spectral regions that allow simulating human color vision capabilities. However, other applications are also possible. Background Art

[0003] Spectrometer devices are known to be efficient tools for obtaining information about the spectral properties of an object when emitting, irradiating, reflecting and / or absorbing light. Spectrometer devices can therefore assist in analyzing samples or other tasks where information about the spectral properties of an object is of interest.

[0004] Typically, in a spectrometer, spectral information is obtained via one or more detectors and one or more wavelength-selective optical elements (e.g., one or more dispersive optical elements, filters (e.g., bandpass filters), prisms, gratings, interferometers, etc.). The detectors can include any type of photosensitive element, such as one or more single-pixel or multi-pixel detectors, line detectors, or array detectors with a one-dimensional or two-dimensional array of pixels. Furthermore, the spectrometer can include one or more light sources. Therefore, in spectroscopy, tunable light sources (e.g., lasers) and / or broadband emission light sources (e.g., halogen gas-filled bulbs and / or hot filaments) are commonly used. However, other light sources, such as light-emitting diodes, have also been proposed, either additionally or alternatively, for the visible spectral region.

[0005] As an example, US 2010 / 208261 A1 describes an apparatus for determining at least one optical property of a sample. The apparatus includes a tunable excitation light source for applying excitation light to the sample. The apparatus also includes a detector for detecting detection light emitted from the sample. The excitation light source includes an array of light-emitting diodes, which is configured at least in part as a monolithic array of light-emitting diodes. The monolithic array of light-emitting diodes includes at least three light-emitting diodes, each light-emitting diode having a different emission spectrum.

[0006] US Pat. No. 8,164,050 B2 describes a multi-channel light source assembly for downhole spectroscopy. The assembly includes individual light sources that generate optical signals spanning a spectral range of wavelengths. A combining assembly optically combines the generated signals into a combined signal, while a routing assembly separates the combined signal into a reference channel and a measurement channel. Control circuitry electrically coupled to the light sources modulates each of the light sources at a unique or independent frequency during operation.

[0007] Furthermore, US 7,061,618 B2 describes integrated spectroscopy systems, in which, in some examples, an integrated tunable detector is provided using one or more Fabry-Perot tunable filters. Other examples use integrated tunable light sources that combine one or more diodes (such as superluminescent diodes (SLEDs)) with Fabry-Perot tunable filters or etalons.

[0008] Furthermore, US 5,475,221 A describes an optical device that uses an array of light emitting diodes controlled by a multiplexing scheme to replace conventional broadband light sources in devices such as spectrometers.

[0009] Spectrometers are often subject to various internal and external influences (such as environmental influences) that may affect the results of spectral measurements. To correct for and / or compensate for these influences, various calibration and / or correction methods are known. These calibration methods can be performed once or several times by the manufacturer, for example, under laboratory conditions. However, various online calibration techniques are also known, which can be performed by performing one or more calibration and / or correction steps between two spectral measurements or even during a measurement.

[0010] US 09360366 B1 discloses a self-referencing spectrometer that utilizes a shared aperture as an optical input to simultaneously automatically calibrate and measure the spectrum of a physical object. The simultaneous measurement and self-calibration capabilities enable it to be used as an accessory spectrometer on a mobile computing device, eliminating the need for offline calibration using an external reference light source. The acquired spectral information and captured images can be distributed via a wireless communication network via the mobile computing device.

[0011] DE 102014013848 B4 discloses a miniature spectrometer (specifically, an NIR miniature spectrometer for mobile applications in battery-powered terminals) to overcome the limitations of the aforementioned system configurations in terms of non-miniaturization and hand-holding. It also discloses a miniature spectrometer system and a calibration method. This miniaturized NIR spectrometer design does not require active temperature stabilization. Instead, according to the present invention, as part of a factory temperature calibration procedure, the spectral sensitivity function (QEλ = f(T); measured using an integrated temperature sensor) is recorded at several levels within the expected operating temperature range.

[0012] WO 2019 / 191698 A2 relates to a self-referencing spectrometer for simultaneously measuring a background or reference spectral density and a sample or other spectral density. The self-referencing spectrometer comprises an interferometer optically coupled to receive an input beam and guide the input beam along a first optical path to generate a first interference beam and guide the input beam along a second optical path to generate a second interference beam, wherein each interference beam is generated before an output end of the interferometer. The spectrometer further comprises: a detector optically coupled to simultaneously detect a first interference signal generated from the first interference beam and a second interference signal generated from the second interference beam; and a processor configured to process the first interference signal and the second interference signal and to use the second interference signal as a reference signal when processing the first interference signal.

[0013] US 20210293620 A1 discloses a spectrometer comprising: an illumination device for illuminating a spectral measurement region; a detection unit for detecting electromagnetic radiation from the spectral measurement region; and a spectral element disposed in a beam path between the illumination device and the detection unit. The illumination device comprises: a light-emitting diode having a first central wavelength, the light-emitting diode being designed to emit first electromagnetic radiation having a first spectrum; and a light-emitting element for converting a first component of the first electromagnetic radiation having the first spectrum into second electromagnetic radiation having a second spectrum. The first central wavelength is 550 nm or 3000 nm, or has a value between 550 nm and 3000 nm. The first spectrum and the second spectrum overlap.

[0014] US 06667802 B2 discloses a method for calibrating a spectral detection system. The method includes: providing a plurality of packages, each of the plurality of packages containing a group of articles, wherein each group of articles has a known composition; measuring reflectance values ​​of each group of articles to thereby obtain a reference reflectance value set; normalizing the reference reflectance value set to thereby generate a normalized reference reflectance value set; and storing the normalized reference reflectance value set.

[0015] US 06717669 B2 discloses an automatically calibrated spectrometer and method that measures the transmission or reflectance of a sample as a function of wavelength without requiring lengthy calibration. A reflectance spectrometer and a transmission spectrometer, as well as an automatically calibrated method for use therewith, are disclosed. Light is focused onto a sample using a lens or similar optical element that transmits the light to the sample, reflects the light impinging on it, and transmits the light reflected from the sample. If the light reflected from the first lens and the sample is monitored, very useful information about the response of the system over time can be obtained. The reflected light from the first lens and the sample is monitored, and the reflected light is used to correct for changes in the system over time.

[0016] US 09448114 B2 discloses a spectrometer comprising a plurality of isolated optical channels, each of which comprises a plurality of isolated optical paths. The isolated optical paths reduce crosstalk between the optical paths, reduce the length of the spectrometer, and improve resolution. In many embodiments, the isolated optical paths comprise isolated parallel optical paths, which significantly reduce the length of the device. In many embodiments, each isolated optical path extends from a filter in a filter array, through a lens in a lens array, through a channel in a support array, and to a region of a sensor array. Each region of the sensor array comprises a plurality of sensor elements, wherein the position of the sensor element corresponds to a wavelength of received light, the wavelength being based on the angle of the light received at that position, the focal length of the lens, and the center wavelength of the filter.

[0017] US 2013 / 0093936 A1 discloses an energy dispersive device, spectrometer, and method for evaluating the composition of a substance in situ without the need for specialized training or expensive equipment. The energy dispersive device or spectrometer can be used with a digital camera or mobile phone. The device comprises a stack of monodispersive or bidispersive diffraction gratings that are rotated about their normals to produce multiple diffraction orders, based on which qualitative or quantitative properties of the substance can be meaningfully measured and determined.

[0018] EP 2 818 837 A1 discloses a non-contact dental device for determining tooth color, comprising an illumination device for illuminating the tooth to be examined with ambient illumination light. The device inventively provides at least one color sensor for acquiring light reflected by the tooth and performing a spectral examination of the light. A filter device is associated with the color sensor for at least partially separating a signal component originating from the illumination light from a signal component originating from the ambient light. An evaluation device for determining tooth color based on the signal component originating from the illumination light is arranged downstream of the filter device.

[0019] US 2002 / 0109839 A1 discloses a method for calibrating a spectral detection system, the method comprising: providing a plurality of packages, each of the plurality of packages containing a group of items, wherein each group of items has a known composition; measuring the reflectance value of each group of items and thereby obtaining a reference reflectance value set; normalizing the reference reflectance value set and thereby generating a normalized reference reflectance value set; and storing the normalized reference reflectance value set.

[0020] DE 10 2014 013 848 B4 discloses a miniature spectrometer designed as a miniaturized near-infrared spectrophotometer, the miniature spectrometer having an InGaAs detector array and an integrated temperature sensor for measuring a temperature calibration step to store information about the detector temperature. The miniature spectrometer is designed to operate with mathematical temperature compensation based on converting the current QE(T) function into a function valid for a set temperature at the time of measurement, whereby the measured spectrum can be corrected with the obtained QE(T) function and corresponds to a virtual spectrum at the measured set temperature.

[0021] US 2011 / 0241549 A1 discloses a light generating system comprising a plurality of solid-state emitters (SSEs) and a stability control system for controlling the spectral stability of the SSEs. In certain cases, the stability control system may include a power regulator for regulating power supplied to a subset of the plurality of SSEs; a constant current circuit connected to the power regulator to provide a constant current to the subset of SSEs; a current regulation setpoint connected to the constant current circuit; and a controller configured to set the regulation setpoint based on metering data related to the status of the SSEs.

[0022] Thomas Tetzlaff et al., in their paper "Hardware implementation of LED forward voltage measurement for junction temperature estimation," presented at the 19th International Conference on Thermal, Mechanical, and Multiphysics Simulation and Experimentation in Microelectronics and Microsystems (EUROSIME) on April 15, 2018, and published by IEEE, describe how overheating of LED junctions can significantly reduce the lifetime of LEDs. Color and light intensity typically change with temperature, resulting in a decrease in light quality. Therefore, thermal management is essential to prevent overheating. Even brief temperature spikes can affect the lifetime and light quality of LEDs.

[0023] Despite the numerous advantages of known methods and devices, several technical challenges remain in the field of spectroscopy and spectroscopic devices, particularly in the near-infrared range. Consequently, there is a need for calibration techniques that correct for various influences, particularly those that can be performed online in the field (i.e., at the location where the spectral measurement is performed). Temperature is known to have a significant impact on the results and accuracy of spectral measurements. Temperature variations can occur due to external influences (such as changes in ambient temperature). Additionally or alternatively, temperature variations can result from internal influences (such as currents and resistances within the spectroscopic device, e.g., due to electrical power dissipation). These temperature variations can occur over short periods of time and / or manifest as long-term drift. Furthermore, it must be considered that temperature variations do not necessarily occur globally and / or when the entire spectrometer device is in thermal equilibrium. Consequently, localized temperature variations can occur, particularly at locations that are difficult to monitor, such as locations within the spectrometer device and / or at interfaces within its components (e.g., semiconductor interfaces). Furthermore, the temperature dependence of the system can change. For example, even if the temperature remains constant, a system may exhibit different performance over time (e.g. due to degradation, aging, or changes in optical or electrical interfaces from frequent use).

[0024] Problem to be solved

[0025] It is therefore desirable to provide a method and an apparatus that at least partially addresses the above technical challenges and at least substantially avoids the disadvantages of known methods and apparatuses. In particular, the present invention aims to provide a spectrometer apparatus and a method for obtaining spectroscopic information about at least one object, which spectrometer apparatus and method are capable of correcting for external and / or internal influences, such as temperature variations. Summary of the Invention

[0026] This problem is solved by a method of operating a spectrometer device for obtaining spectroscopic information about at least one object, a calibration method for compiling a set of correction information items, a spectrometer device for obtaining spectroscopic information about at least one object, a computer program, a computer-readable storage medium, and a non-transitory computer-readable medium. Advantageous embodiments are listed in the dependent claims and throughout the description, which can be implemented individually or in any arbitrary combination.

[0027] In a first aspect, a method for operating a spectrometer apparatus for obtaining spectroscopic information about at least one object is disclosed. The method comprises the following steps, which may be performed in a given order. However, different orders are also possible. In particular, one, more than one, or even all of the method steps may be performed once or repeatedly. Furthermore, the method steps may be performed sequentially, or alternatively, one or more method steps may be performed in a timely overlapping manner, or even in parallel, and / or in combination. The method may further comprise additional method steps not listed.

[0028] As used herein, the term "spectrographic device" is a broad term and is to be given its ordinary and customary meaning for those skilled in the art and is not limited to a special or customary meaning. The term may specifically, but is not limited to, refer to an optical device configured to obtain at least one item of spectral information about at least one object. Specifically, the at least one spectral information item may refer to at least one optical property or optically measurable property determined as a function of wavelength for one or more different wavelengths. More specifically, the optical property or optically measurable property and the at least one spectral information item may relate to at least one property that characterizes at least one of transmission, absorption, reflection, and emission of the at least one object, either intrinsically or after exposure to external light. The at least one optical property may be determined for one or more wavelengths. The spectroscopic device may specifically be a device capable of recording signal intensities for corresponding wavelengths or subregions (e.g., wavelength intervals) of a spectrum, wherein the signal intensities may be provided as electrical signals that can be used for further evaluation.

[0029] By way of example, a spectrometer device may be or may include a device that allows for measuring at least one spectrum (e.g., for measuring spectral flux, in particular as a function of wavelength or detection wavelength). By way of example, the spectrum may be acquired in absolute units or relative units (e.g., relative to at least one reference measurement). Thus, by way of example, the acquisition of at least one spectrum may specifically focus on measuring spectral flux (in W / nm) or a spectrum (in W) relative to at least one reference material, which may describe a material property (e.g., a change in reflectivity with wavelength). Additionally or alternatively, the reference measurement may be based on a reference light source, an optical reference path, a calculated reference signal (e.g., a calculated reference signal from literature), and / or a reference device.

[0030] Specifically, at least one spectrometer device may be a diffuse reflectance spectrometer device configured to obtain spectral information from light diffusely reflected by at least one object (e.g., at least one sample). Additionally or alternatively, at least one spectrometer device may be or may include an absorption spectrometer and / or a transmission spectrometer. In particular, measuring a spectrum with the spectrometer device may include measuring absorption in a transmission configuration. Specifically, the spectrometer device may be configured to measure absorption in a transmission configuration. However, as outlined above, other types of spectrometer devices are also possible.

[0031] Specifically, and as will be further detailed below, at least one spectrometer device can include at least one light source, which can be, for example, at least one of a tunable light source, a light source having at least one fixed emission wavelength, and a broadband light source. As will be further detailed below, the spectrometer device further includes at least one detector device configured to detect light, such as at least one of light transmitted, reflected, or emitted from at least one object. As will be further detailed below, the spectrometer device can further include at least one wavelength-selective element, such as at least one of a grating, a prism, and a filter (e.g., a variable-length filter having varying transmission characteristics across its lateral extension). The wavelength-selective element can be used to separate incident light into a spectrum of component wavelength signals, the respective intensities of which are determined using a detector (e.g., a detector array as described in more detail below).

[0032] The spectrometer device may specifically be a portable spectrometer device. As used herein, the term "portable" is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not limited to a special or customized meaning. The term may specifically refer to, but is not limited to, the property of at least one object being moved by human power (such as by a single user). In particular, the weight of the object characterized by the term "portable" may not exceed 10 kg, specifically not exceed 5 kg, more specifically not exceed 1 kg or even not exceed 500 g. Additionally or alternatively, the size of the object characterized by the term "portable" may be such that the object extends no more than 0.3 m in any dimension, specifically no more than 0.2 m in any dimension. In particular, the volume of the object may not exceed 0.03 m³, specifically not more than 0.01 m³, more specifically not more than 0.001 m³ or even not more than 500 mm 3. In particular, as an example, the portable spectrometer device may have dimensions of, for example, 10 mm × 10 mm × 5 mm. In particular, the portable spectrometer device may be part of a mobile device, such as a laptop computer, a tablet computer, a mobile phone (such as a smartphone), a smartwatch and / or a wearable computer (also referred to as a “wearable device”, such as a body-worn computer (such as a wristband or a watch)), or may be attachable to a mobile device. In particular, the weight of the spectrometer device, in particular the portable spectrometer device, may be in the range of 1 g to 100 g, more particularly in the range of 1 g to 10 g.

[0033] As used herein, the term "spectroscopy information" (also referred to as "spectral information" or "spectral information item") is a broad term and is to be given its ordinary and customary meaning for those skilled in the art and is not limited to a special or customary meaning. The term may specifically, but is not limited to, an item of information about at least one object and / or radiation emitted by at least one object, characterizing at least one optical property of the object, more specifically, characterizing, for example, at least one item of information that qualitatively and / or quantifies at least one of the transmission, absorption, reflection, and emission of the at least one object. By way of example, at least one item of spectral information may include at least one item of intensity information, such as information about the intensity of at least one of light transmitted, absorbed, reflected, or emitted by the object, for example, as a function of wavelength or wavelength sub-range within one or more wavelengths (e.g., within a wavelength range). Specifically, the intensity information may correspond to, or be derived from, a signal intensity (particularly an electrical signal) recorded by a spectrometer device that is associated with a wavelength or wavelength range of the spectrum.

[0034] The spectrometer device can be specifically configured to acquire at least one spectrum, or at least a portion of a spectrum, of detection light propagating from the object to the spectrometer. The spectrum can describe a radiometric unit of spectral flux, for example given in watts per nanometer (W / nm), or in other units, for example as a function of the wavelength of the detection light. Thus, the spectrum can describe the optical power of light within a specific wavelength band, for example in the NIR spectral range. The spectrum can include one or more optical variables that vary with wavelength, such as power spectral density, an electrical signal obtained by optical measurement, etc. As an example, the spectrum can indicate the power spectral density and / or spectral flux of the object (e.g., a sample), for example relative to a reference sample, such as the transmittance and / or reflectance of the object (particularly the sample).

[0035] As an example, the spectrum may include at least one measurable optical variable or property of the detection light and / or the object, the optical variable or property being in particular a function of the illumination light and / or the detection light. As an example, the at least one measurable optical variable or property may include at least one radiometric quantity, such as at least one of spectral density, power spectral density, spectral flux, radiant flux, radiant intensity, spectral radiant intensity, irradiance, and spectral irradiance. Specifically, as an example, the spectrometer device (in particular the detector) may measure power in Watts per square meter (W / m 2 ) or more specifically measured in watts per square meter per nanometer (W / m 2 Based on the measured quantities, the spectral flux in Watts per nanometer (W / nm) and / or the radiant flux in Watts (W) can be determined (e.g., calculated) by taking into account the area of ​​the detector.

[0036] As used herein, the term "object" is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not limited to a special or customized meaning. The term may specifically refer to, but is not limited to, any body selected from animate objects and inanimate objects. Thus, by way of example, at least one object may include one or more items and / or one or more parts of an item, wherein at least one item or at least one part thereof may include at least one component that can provide a spectrum suitable for investigation. Additionally or alternatively, an object may be or may include one or more organisms and / or one or more parts thereof, such as one or more body parts of a human (e.g., a user) and / or an animal. In particular, an object may include at least one sample that can be analyzed in whole or in part by spectroscopic methods. By way of example, an object may be or may include at least one of the following: human or animal skin; edibles, such as fruit; plastics; and textiles.

[0037] The method comprises the following steps:

[0038] i. illuminating the object with illumination light generated by at least one light source of the spectrometer device, the light source comprising at least one light-emitting diode and at least one luminescent material for photoconverting the primary light generated by the light-emitting diode;

[0039] ii. determining at least one actual value of at least one operating parameter of the spectrometer device by using at least one drive unit of the spectrometer device, the drive unit being configured to electrically drive the light source;

[0040] iii. detecting detection light from the object using at least one detector of the spectrometer device and generating at least one detector signal; and

[0041] iv. deriving spectroscopic information about the object by evaluating the detector signal using at least one evaluation unit of the spectrometer device, the evaluation unit being configured for selecting at least one correction information item from a predetermined set of correction information items depending on the actual value of the at least one operating parameter and for taking into account the selected correction information item to derive the spectroscopic information.

[0042] In step i., the object is illuminated with illumination light generated by at least one light source of the spectrometer device, the light source comprising at least one light-emitting diode and at least one luminescent material for photoconverting primary light generated by the light-emitting diode.

[0043] As further used herein, the term "light" is a broad term and is to be given its ordinary and customary meaning to those of ordinary skill in the art and is not limited to a special or customary meaning. The term may specifically refer to, but is not limited to, electromagnetic radiation in one or more of the infrared spectral range, the visible spectral range, and the ultraviolet spectral range. As used herein, the term "ultraviolet spectral range" generally refers to electromagnetic radiation having a wavelength of 1 nm to 380 nm, preferably 100 nm to 380 nm. Furthermore, in accordance in part with the version of standard ISO-21348 in effect as of the date of this document, the term "visible spectral range" generally refers to the spectral range of 380 nm to 760 nm. The term "infrared spectral range" (IR) generally refers to electromagnetic radiation in the range of 760 nm to 1000 µm, of which the range of 760 nm to 1.5 µm is generally referred to as the "near infrared spectral range" (NIR), the range of 1.5 µm to 15 µm is referred to as the "mid infrared spectral range" (MidIR), and the range of 15 µm to 1000 µm is referred to as the "far infrared spectral range" (FIR). Preferably, the light used for the typical purposes of the present invention is light in the infrared (IR) spectral range, more preferably light in the near-infrared (NIR) and / or mid-infrared (MidIR) spectral range, particularly light with a wavelength of 1 µm to 5 µm, preferably 1 µm to 3 µm. This is because many material properties or chemical composition characteristics of an object can be derived from the NIR spectral range. However, it should be noted that spectral analysis in other spectral ranges is also applicable and falls within the scope of the present invention.

[0044] Therefore, as used herein, the term "light source" (also referred to as "illumination source") is a broad term and is to be given its ordinary and customary meaning to those of ordinary skill in the art and is not limited to a special or customized meaning. The term may specifically refer to, but is not limited to, any device configured to generate or provide light in the sense defined above. The light source may specifically be or may include at least one electric light source, such as an electrically driven light source.

[0045] As will be further described below, the light source can generally be implemented in a variety of ways. Thus, for example, the light source can be part of the spectrometer device within the spectrometer device housing. Alternatively or additionally, however, the at least one light source can also be arranged external to the housing, for example as a separate light source. The light source can be arranged separately from the object and illuminate the object from a distance.

[0046] In spectroscopy, it is important to distinguish between various light sources and light paths. In the context of the present invention, the nomenclature used first refers to light propagating from a light source to an object as "illuminating light" (or "illumination light"). Secondly, light propagating from an object to a detector is referred to as "detection light." Detection light can include at least one of the following: illumination light reflected by an object, illumination light scattered by an object, illumination light transmitted by an object, or luminescence light generated by an object (e.g., phosphorescence or fluorescence generated by an object after optical, electrical, or acoustic excitation of the object by the illumination light). Therefore, detection light can be generated directly or indirectly by illumination of an object with illumination light.

[0047] Furthermore, as will be described in more detail below, within the light source itself, a distinction can be made between various light sources, such as primary and secondary light sources. Thus, "primary light" (also referred to as "pump light"), as will be described in more detail below, can be generated by a primary light source (such as at least one light-emitting diode) and can subsequently be transformed into "secondary light," such as by using light conversion (e.g., via one or more phosphor materials). The illumination light can be or include at least one of the primary light or a portion thereof, the secondary light or a portion thereof, or a mixture of the primary and secondary light.

[0048] Therefore, as used herein, the term "illumination" is a broad term and is to be given its ordinary and customary meaning to those of ordinary skill in the art and is not limited to a special or customized meaning. The term may specifically refer to, but is not limited to, the process of exposing at least one element to light.

[0049] As outlined above, the light source comprises at least one light-emitting diode and at least one luminescent material for photoconverting primary light generated by the light-emitting diode, wherein, in particular, the illumination light may be a combination of the primary light and the light generated by photoconversion of the luminescent material or light generated by photoconversion of the luminescent material (also referred to as secondary light).

[0050] As used herein, the term "light emitting diode," or simply "LED," is a broad term and is to be given its ordinary and customary meaning to those of ordinary skill in the art and is not to be limited to a special or customary meaning. The term may specifically refer to, but is not limited to, an optoelectronic semiconductor device capable of emitting light when an electric current flows through the device. Optoelectronic semiconductor devices can be configured to generate light due to one or more of a variety of physical processes, including spontaneous emission, induced emission, decay of metastable excited states, and the like. Thus, by way of example, a light emitting diode may include one or more of the following: a light emitting diode based on spontaneous emission of light (particularly an organic light emitting diode), a superluminescent light emitting diode (sLED), or a laser diode (LD). Hereinafter, without narrowing down the possible embodiments of a light emitting diode to any of the aforementioned physical principles or setups, the abbreviation "LED" will be used for any type of light emitting diode. Specifically, an LED may include at least two layers of semiconductor material, wherein light may be generated at at least one interface between the at least two semiconductor material layers, particularly due to the recombination of positive and negative charges (e.g., electron-hole recombination). The at least two semiconductor material layers may have different electrical properties, such as at least one of the layers being an n-doped semiconductor material and at least one of the layers being a p-doped semiconductor material. Thus, as an example, an LED may include at least one pn junction and / or at least one pin structure. However, it should be noted that other device structures are also possible. The at least one semiconductor material may specifically be or may include at least one inorganic semiconductor material. However, it should be noted that organic semiconductor materials may be used in addition or alternatively.

[0051] Typically, as will be further detailed below, an LED can convert electrical current into light, specifically into primary light, more specifically into blue primary light. Thus, the LED can specifically be a blue LED. The LED can be configured to generate primary light, also referred to as "pump light." Thus, the LED can also be referred to as a "pump LED." The LED can specifically include at least one LED chip and / or at least one LED die. Thus, the semiconductor element of the LED can include a bare LED chip.

[0052] Various types of LEDs suitable for generating primary light are known to those skilled in the art and can also be used in the present invention. In particular, pn junction diodes can be used. By way of example, one or more LEDs selected from the group consisting of indium gallium nitride (InGaN)-based LEDs, GaN-based LEDs, InGaN / GaN alloy-based LEDs, or combinations thereof, and / or other LEDs can be used. Additionally or alternatively, quantum well LEDs, such as one or more quantum well LEDs based on InGaN, can also be used. Additionally or alternatively, superluminescent LEDs (sLEDs) and / or quantum cascade lasers can be used.

[0053] As used herein, the term "luminescence" is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not limited to a special or customized meaning. The term may specifically refer to, but is not limited to, the process of spontaneous emission of light by a substance that is not caused by heat. In particular, luminescence may refer to radiation from a cold body. More specifically, luminescence may be initiated or stimulated by irradiation with light, in which case luminescence is also referred to as "photoluminescence". In the context of the present invention, the property of a material that is capable of luminescence is referred to by the adjective "luminescent". At least one luminescent material may specifically be a photoluminescent material, i.e. a material that is capable of emitting light after absorbing a photon or excitation light. In particular, the luminescent material may have a positive Stokes shift, which generally may refer to the fact that the secondary light is red-shifted relative to the primary light.

[0054] Thus, at least one luminescent material can form at least one converter (also called a light converter) that converts primary light into secondary light having different spectral characteristics than the primary light. Specifically, the spectral width of the secondary light can be greater than the spectral width of the primary light and / or the emission center of the secondary light can be shifted (specifically, red-shifted) compared to the primary light. Specifically, at least one luminescent material can have absorption in the ultraviolet and / or blue spectral ranges and emission in the near-infrared and / or infrared spectral ranges. Thus, typically, the luminescent material or converter can form at least one component of a phosphor LED, which concentrates primary light or pump light, particularly in the blue spectral range, into light having a longer wavelength, for example, in the near-infrared or infrared spectral range.

[0055] Various types of conversion and / or luminescence are known and can be used in the context of the present invention. Thus, in particular, the conversion can occur via a dipole-allowed transition in the luminescent material (also known as fluorescence) and / or via a dipole-forbidden, and therefore longer-lived, transition in the luminescent material (often also known as phosphorescence).

[0056] Thus, the luminescent material may specifically form at least one converter or light converter. The luminescent material may form at least one of a converter sheet, a luminescent coating (specifically a fluorescent coating) on ​​an LED, and a phosphor coating on an LED. As an example, the luminescent material may include one or more of the following materials: cerium-doped YAG (YAG:Ce 3+ or Y3Al5O 12 :Ce 3+ ); rare earth-doped Sialon; copper and aluminum co-doped zinc sulfide (ZnS:Cu,Al).

[0057] Together, an LED and a luminescent material can form a so-called "phosphor LED." Therefore, as used herein, the term "phosphor light-emitting diode," or simply "phosphor LED," is a broad term and is to be given its ordinary and customary meaning for those skilled in the art and is not limited to a special or customary meaning. The term may specifically, but is not limited to, the combination of at least one light-emitting diode configured to generate primary light, or pump light, and at least one luminescent material (also referred to as a "phosphor") configured to photoconvert the primary light generated by the light-emitting diode. A phosphor LED can form a packaged LED light source comprising an LED die (e.g., a blue LED emitting blue pump light) and a phosphor that, for example, fully or partially coats the LED and, for example, is configured to convert the primary light, or blue light, into light with different spectral characteristics (specifically, into near-infrared light). Typically, a phosphor LED can be packaged in a housing or unpackaged. Thus, the LED and the at least one luminescent material for photoconverting the primary light generated by the light-emitting diode can be housed in a common housing. Alternatively, however, the LED may also be an unpackaged or bare LED, which may be fully or partially covered with luminescent material, such as by providing one or more layers of luminescent material on the LED die.A phosphor LED may typically form the emitter or light source itself.

[0058] In a light source (particularly a phosphor LED), at least one luminescent material can be positioned relative to a light-emitting diode (LED) such that heat can be transferred from the diode to the luminescent material. More specifically, the luminescent material can be positioned such that heat can be transferred via one or both of thermal radiation and thermal conduction (more preferably thermal conduction). Thus, by way of example, the luminescent material can be in thermal and / or physical contact with the light-emitting diode. By way of example, the luminescent material can form one or more coatings or layers that are in contact with or in close proximity to the light-emitting diode, such as contact with one or more of the semiconductor materials of the light-emitting diode. Thus, the temperature of the luminescent material and the temperature of the light-emitting diode can generally be coupled.

[0059] The at least one luminescent material can specifically form at least one layer. In general, various alternative approaches to positioning the luminescent material relative to the LED are possible, which can be used individually or in combination. First, the luminescent material (e.g., at least one layer of luminescent material, such as a phosphor) can be positioned directly on the LED, also referred to as "direct attachment," e.g., with no material between the LED and the luminescent material, or with one or more transparent materials between them, such as one or more transparent materials (particularly transparent to the primary light) between the LED and the luminescent material. Thus, by way of example, a coating of luminescent material can be placed directly or indirectly on the LED. Additionally or alternatively, by way of example, the luminescent material can form at least one converter, such as at least one converter disk, which can be placed on top of the LED, for example, by attaching the converter to the LED with an adhesive. Additionally or alternatively, the luminescent material can also be positioned remotely, such that the primary light from the LED must traverse an intermediate light path before reaching the luminescent material. This placement can also be referred to as "remote placement" or "remote phosphor." Similarly, by way of example, a remotely positioned luminescent material can form a solid or converter, such as a disk or converter disk. Furthermore, in the case of remote placement, the luminescent material can also be a coating. In particular, a light-transmitting object (e.g., a thin glass substrate, a module window) comprising and / or made of glass or plastic can be coated with a phosphor. Alternatively, a reflective surface can be coated with a phosphor. This can be a flat or rough reflector, which can comprise and / or be made of a substrate of a highly reflective material (e.g., silicon), or a flat or rough surface (e.g., glass or plastic) coated with gold, silver, aluminum, or chromium. One or more optical elements, such as lenses, prisms, gratings, reflectors, apertures, or combinations thereof, can be placed in the intermediate light path. Specifically, an optical system with imaging properties can be placed in the intermediate light path, between the LED and the luminescent material. Thus, for example, the primary light can be focused or concentrated onto the converter.

[0060] In step ii., at least one actual value of at least one operating parameter of the spectrometer device is determined by using at least one drive unit of the spectrometer device, the drive unit being configured for electrically driving the light source.

[0061] As used herein, the term "drive" is a broad term and is to be given its ordinary and conventional meaning to one of ordinary skill in the art and is not limited to a special or customized meaning. The term may specifically refer to, but is not limited to, the process of providing one or both of at least one control parameter and / or electrical power to another device. Therefore, as used herein, the term "drive unit" is a broad term and is to be given its ordinary and conventional meaning to one of ordinary skill in the art and is not limited to a special or customized meaning. The term may specifically refer to, but is not limited to, any device or combination of devices configured to provide one or both of at least one control parameter and / or electrical power to another device (such as, in this example, at least one light source).

[0062] For example, the driver unit may be specifically configured to at least measure and control one or more electrical parameters of the electrical power supplied to the light source (specifically, to at least one light-emitting diode). As an example, the driver unit may be configured to supply current to an LED, specifically to control the current through the LED. For example, the driver unit may be configured to adapt and measure the voltage supplied to the LED required to achieve a specific current through the LED. The driver unit may include a measurement unit, which may specifically include one or more of the following: a current source, a voltage source, a current measuring device (such as an ammeter), a voltage measuring device (such as a voltmeter), a power measuring device, or a thermometer. Specifically, the driver unit may include at least one current source for supplying at least one predetermined current to the LED. The current source may specifically be configured to adjust or control the voltage applied to the LED to generate the predetermined current. As an example, the driver unit may include one or more electrical components (such as an integrated circuit) for driving the light source. The driver unit may be fully or partially integrated into the light source, or may be separate from the light source.

[0063] The drive unit may further determine at least one operating parameter of the spectrometer device, in particular by providing and / or measuring it. As used herein, the term "operating parameter" is a broad term and is to be given its ordinary and conventional meaning for a person skilled in the art and is not limited to a special or customized meaning. The term may specifically refer to, but is not limited to, factors and / or conditions that directly and / or indirectly influence the operating process and / or the function of the device (in particular the spectrometer device), in particular the function of the spectrometer device in determining at least one spectroscopic information about the object. At least one control parameter and / or the electric power provided by the drive unit may be an operating parameter. Alternatively or additionally, at least one external factor of the environment in which the spectrometer device operates (such as an environmental condition, in particular the ambient temperature) may be an operating parameter. Further operating parameters may exist, in particular as described elsewhere herein.

[0064] In step iii., detection light from the object is detected by using at least one detector of the spectrometer device, and at least one detector signal is generated.

[0065] As further outlined above, a spectrometer device includes at least one detector configured to detect detection light, such as diffusely reflected light, from an object. As used herein, the verb "detect" is a broad term and is to be given its ordinary and customary meaning for those skilled in the art and is not limited to a special or customary meaning. The term may specifically refer to, but is not limited to, the process of at least one of qualitatively and / or quantitatively determining, measuring, and monitoring at least one parameter (such as at least one of a physical parameter, a chemical parameter, and a biological parameter). Specifically, a physical parameter may be or may include an electrical parameter. Therefore, as used herein, the term "detector" is a broad term and is to be given its ordinary and customary meaning for those skilled in the art and is not limited to a special or customary meaning. The term may specifically refer to, but is not limited to, any device configured to detect, i.e., to at least one of qualitatively and / or quantitatively determine, measure, and monitor at least one parameter (such as at least one of a physical parameter, a chemical parameter, and a biological parameter). The detector may be configured to generate at least one detector signal, more specifically at least one electrical detector signal, such as an analog and / or digital detector signal, that provides information about the at least one parameter measured by the detector. The detector signal can be provided by the detector directly or indirectly to the evaluation unit, so that the detector and the evaluation unit can be directly or indirectly connected. The detector signal can be used as a "raw" detector signal and / or can be processed or preprocessed (e.g., by filtering, etc.) before further use. Thus, the detector can include at least one processing device and / or at least one preprocessing device, such as at least one of an amplifier, an analog / digital converter, an electrical filter, and a Fourier transform.

[0066] In this example, the detector is configured to detect light propagating from the object to the spectrometer device, or more specifically, to a detector of the spectrometer device. According to the aforementioned nomenclature, this light is referred to as "detection light." Specifically, the detector may be or may include at least one optical detector. The optical detector may be configured to determine at least one optical parameter, such as the intensity and / or power of light irradiating at least one sensitive region of the detector. More specifically, the optical detector may include at least one photosensor and / or at least one optical sensor, such as at least one of a photodiode, a photocell, a photoresistor, a phototransistor, a thermopile sensor, a photoacoustic sensor, a pyroelectric sensor, a photomultiplier, and a bolometer. The detector may be configured to generate at least one detector signal, more specifically at least one electrical detector signal in the aforementioned sense, that provides information about at least one optical parameter, such as the power and / or intensity of light irradiating the detector or a sensitive region of the detector.

[0067] The detector may include a single optically sensitive element or region or a plurality of optically sensitive elements or regions. In particular, the detector may be or may include at least one detector array (more particularly an array of photosensitive elements), as will be described in further detail below. Each photosensitive element may include at least a photosensitive region, which may be adapted to generate an electrical signal depending on the intensity of incident light, wherein the electrical signal may in particular be provided to an evaluation unit, as will be described in further detail below.

[0068] The photosensitive area comprised by each optically sensitive element may in particular be a single, homogeneous photosensitive area configured to receive incident light impinging on the respective optically sensitive element. However, other arrangements of the optically sensitive elements are also conceivable.

[0069] The array of optically sensitive elements can be designed to generate a detector signal, preferably an electronic signal, which is associated with the intensity of the incident light impinging on the individual optically sensitive elements. The detector signal can be an analog signal and / or a digital signal. Accordingly, the electronic signals of adjacent pixelated sensors can be generated simultaneously or in a temporally consecutive manner. For example, during a row scan or line scan, a series of electronic signals can be generated corresponding to a series of individual optically sensitive elements arranged in a row. In addition, these individual optically sensitive elements can preferably be active pixel sensors, which can be suitable for amplifying the electronic signals before providing them to the evaluation unit. For this purpose, the detector can include one or more signal processing devices, such as one or more filters and / or analog-to-digital converters, for processing and / or preprocessing the electronic signals.

[0070] In the case where the detector comprises an array of optically sensitive elements, the detector can, by way of example, be selected from any known pixelated sensor, in particular, from pixelated organic camera elements, preferably pixelated organic camera chips, or from pixelated inorganic camera elements, preferably pixelated inorganic camera chips, more preferably from CCD chips or CMOS chips, which are the types commonly used in various cameras today. Alternatively, the detector can generally be or include a photoconductor, in particular an inorganic photoconductor, especially PbS, PbSe, Ge, InGaAs, extended InGaAs, InSb, or HgCdTe. As another alternative, the detector can include at least one of a pyroelectric element, a bolometer element, or a thermopile detector element. Thus, a camera chip having a matrix of 1 × N pixels or M × N pixels can be used, where, by way of example, M can be <10 and N can be in the range of 1 to 50, preferably 2 to 20, and more preferably 5 to 10. Furthermore, a monochrome camera element, preferably a monochrome camera chip, can be used, wherein the monochrome camera element can be selected differently for each optically sensitive element, in particular depending on the wavelength that varies across a range of optical sensors.

[0071] Hence, the array may be adapted to provide a plurality of electrical signals which may be generated by the photosensitive areas of the optically sensitive elements comprised by the array.The electrical signals provided by the array of the spectrometer device may be forwarded to an evaluation unit.

[0072] In step iv., spectroscopic information about the object is derived therefrom by evaluating the detector signal using at least one evaluation unit of the spectrometer device, the evaluation unit being configured for selecting at least one correction information item from a predetermined set of correction information items depending on the actual value of the at least one operating parameter and for taking into account the selected correction information item to derive the spectroscopic information.

[0073] As further described above, the spectrometer device includes at least one evaluation unit for evaluating at least one detector signal generated by a detector and for obtaining spectroscopic information about the object from the detector signal. As used herein, the term "evaluation" is a broad term and will be given its common and conventional meaning for those of ordinary skill in the art and is not limited to a special or customized meaning. The term can specifically refer to, but is not limited to, a process of processing at least one first information item so as to thereby generate at least one second information item. Therefore, as used herein, the term "evaluation unit" is a broad term and will be given its common and conventional meaning for those of ordinary skill in the art and is not limited to a special or customized meaning. The term can specifically refer to, but is not limited to, any device or combination of devices configured to evaluate or process at least one first information item so as to generate at least one second information item thereof. Therefore, specifically, the evaluation unit can be configured to process at least one input signal and generate at least one output signal thereof. As an example, the at least one input signal can include at least one detector signal provided directly or indirectly by at least one detector and at least one signal provided directly or indirectly by a drive unit.

[0074] By way of example, the evaluation unit may be or may include one or more integrated circuits (such as one or more application-specific integrated circuits (ASICs)) and / or one or more data processing devices (such as one or more computers, digital signal processors (DSPs), and field-programmable gate arrays (FPGAs)), preferably one or more microcomputers and / or microcontrollers. Additional components may be included, such as one or more preprocessing devices and / or data acquisition devices, such as one or more devices for receiving and / or preprocessing detector signals, such as one or more A / D converters and / or one or more filters. Furthermore, the evaluation unit may include one or more data storage devices. Furthermore, the evaluation unit may include one or more interfaces, such as one or more wireless interfaces and / or one or more wired interfaces.

[0075] At least one evaluation unit can be adapted to execute at least one computer program, such as at least one computer program that performs or supports the step of generating the information item. As an example, one or more algorithms can be implemented that, using at least one detector signal and at least one operating parameter as input variables, can perform a predetermined transformation for obtaining spectroscopic information about the object, such as for obtaining a corrected spectrum and / or for obtaining at least one item of spectroscopic information describing at least one characteristic of the object. At least one further parameter can be considered as an input variable and / or included in the input variable. The evaluation unit can be configured to take into account at least one further parameter and / or variable.

[0076] For this purpose, the evaluation unit can, in particular, include at least one data processing device (also referred to as a processor, in particular an electronic data processing device) that can be designed to generate the desired information by evaluating the detector signal and / or at least one operating parameter. The evaluation unit can be configured to take into account at least one additional parameter and / or variable. The evaluation unit can use any desired process to generate the desired information, such as by calculation and / or using at least one stored and / or known relationship.

[0077] The evaluation unit can specifically be configured to perform at least one digital signal processing (DSP) technique, in particular at least one Fourier transform, on the primary detector signal or any secondary detector signals derived therefrom. Additionally or alternatively, the evaluation unit can be configured to perform one or more further digital signal processing techniques, such as windowing, filtering, the Goertzel algorithm, cross-correlation, and autocorrelation, on the primary detector signal or any secondary detector signals derived therefrom. In addition to the detector signal and at least one operating parameter, the relationship can also be influenced. This relationship can be determined or determinable empirically, analytically, or semi-empirically. By way of example, the relationship can include at least one of a model or calibration curve, at least one set of calibration curves, at least one function, or a combination of the aforementioned possibilities. The one or more calibration curves can be stored, for example, in a data storage device and / or a table, for example, as a set of values ​​and their associated function values. Alternatively or additionally, however, at least one calibration curve can also be stored, for example, in parameterized form and / or as a functional equation. A single relationship can be used to process the detector signal into information items. Alternatively, at least one combined relationship is feasible for processing the detector signal. Various possibilities are contemplated, and these possibilities can also be combined.

[0078] As outlined above, the evaluation unit can be specifically configured, for example, via software programming, to select at least one correction information item from a predetermined set of correction information items. Thus, by way of example, the evaluation unit can be configured to determine a spectrum, such as a spectrum indicating a wavelength-dependent photometric or radiometric parameter, from at least one detector signal provided by a detector. Alternatively or additionally, the evaluation unit can be configured to select the at least one correction information item by taking into account at least one operating parameter. The selected at least one correction information item can depend on the at least one operating parameter, in particular, at least two different correction information items can be selected for at least two different operating parameters. The spectrum can be corrected by applying at least one correction function (e.g., a correction factor, such as a wavelength-dependent correction factor of the correction function) to the spectrum, thereby generating a corrected spectrum. The correction information item can be and / or can include and / or can refer to at least one correction function, such as a correction factor, such as a wavelength-dependent correction factor of the correction function. Thus, by way of example, the correction factor can specifically be or can include at least one correction factor that is a function of at least the wavelength of the detection light and at least one operating parameter. As an example, the detector signal may provide a signal as a function of the wavelength of the detected light, wherein by using the correction factor each function value of the detector signal may be multiplied by a corresponding correction factor determined by the at least one operating parameter.

[0079] By way of example, the detector signal may include multiple detector signals that are at least a function of the wavelength of the detection light and, optionally, also a function of time, particularly for time-dependent detector signals. The multiple detector signals may form a spectrum, including options for digital or analog spectra. Thus, by way of example, each detector signal may summarize information from a predetermined spectral range defined by the spectral resolution of the detector. As will be further detailed below, the detector may include multiple photosensors, each sensitive to and / or exposed to a different portion of the spectrum of the detection light within a different spectral range. The detector signals of all the photosensors may form the detector signal, or, by way of example, collectively define the spectral information, a portion thereof, or a precursor thereof. Since the spectral sensitivity range of each photosensor may be known, the intensity of the detection light as a function of the detection wavelength may be derived from this detector signal by combining data pairs for each photosensitive element, each data pair comprising a corresponding signal for the photosensitive element and the sensitivity wavelength. Each of the corresponding signals of the photosensitive element may be corrected using a corresponding correction factor for the corresponding wavelength, wherein the correction factor, as a function of at least one operating parameter, is provided by the evaluation unit. However, it should be noted that other ways of generating spectral information are also possible, such as by sequentially exposing the same detector to different spectral portions of the detection light, for example by using a scannable wavelength selective element. Correction of these sequentially determined spectra can be performed in a similar manner by using a correction factor as a function of wavelength and by correcting the spectra accordingly.

[0080] Therefore, as generally used herein, the term "calibration" is a broad term and is to be given its ordinary and customary meaning for those of ordinary skill in the art and is not limited to a special or customary meaning. The term may specifically, but not limited to, modify or modify at least one item of interest based on one or more information items indicative of parameters known to have an impact on the item of interest. Thus, a measured spectrum can be corrected such that the corrected spectrum corresponds to a spectrum under precisely known conditions or standardized conditions (e.g., at a specific temperature and / or under predetermined operating parameters). The corrected spectrum can then be compared to a reference spectrum determined under precisely known conditions or standardized conditions (e.g., at a specific temperature and / or under predetermined operating parameters). As an example, correction can include modifying the measured spectrum included in the detector signal to correspond to standardized conditions, such as under predetermined operating parameters required to drive a light-emitting diode, particularly under predetermined operating parameters. Thus, step iv. may include correction, in which the measured spectrum derived from the detector signal is modified to correspond to a corrected spectrum, particularly a spectrum that may have been obtained under predetermined standard conditions (e.g., under predetermined operating parameters). Standardized conditions can be defined by using appropriate conditions, for example by using room temperature as the predetermined temperature and / or using a specific measurable quantity required to drive the light emitting diode, in particular a specific forward voltage, measured at room temperature at a predetermined forward current. However, other standard conditions are also feasible.

[0081] To determine the correction factor, specifically the correction function, one or more calibration measurements can be performed, in particular by executing a calibration method that compiles a set of correction information items for use in the methods described elsewhere herein. Thus, the correction can be based on one or more calibration measurements. For example, these calibration measurements can determine at least one detector signal as a function of an operating parameter (and, further, optionally, also as a function of the detection wavelength). As outlined above, at least one condition can be determined as a standard condition, for example, at least one specific operating parameter required to drive the light-emitting diode. For example, the specific operating parameter can be predetermined to define the standard condition, for example, for each wavelength. The correction factor, exemplarily provided by the correction information item, can be determined for each wavelength by determining the ratio between the detector signal measured for any operating parameter and the detector signal measured for the specific operating parameter. Any operating parameter can be known, in particular from at least one measurement via at least one sensor. Thus, in particular, if any operating parameter provided by the drive unit indicates a deviation from a standard, the correction factor can be selected such that the corrected detector signal corresponds to the detector signal that would have been measured under conditions identical to the predetermined standard conditions (e.g., room temperature). Additionally or alternatively, the temperature can be varied in a targeted manner, such as to set or adjust the temperature to two or more target temperatures. Specifically, the standard conditions may include a set of two or more predefined target temperatures and / or a set of corresponding operating parameters. For each of these temperatures, the at least one operating parameter may be measured. The correction factor may then be determined as described above. As used herein, the term "predetermined set of correction information items" is a broad term and will be given its ordinary and conventional meaning to a person of ordinary skill in the art and is not limited to a special or customized meaning. The term may specifically refer to, but is not limited to, a set of multiple correction information items given for at least two different predetermined operating parameter values ​​for the same operating parameter.

[0082] In particular, the correction can be based on a model that describes the functional relationship between the spectral characteristics of the light source and at least one operating parameter, in particular the forward voltage and / or the temperature. The model can be an empirical model, a semi-empirical model or a theoretical model. Thus, as an example, and as will be described in further detail below, the effect of a change in an operating parameter on the measured spectrum (in particular compared to a reference spectrum) can be measured in one or more calibration measurements, for example by using a standardized object or a reference object and measuring the spectrum as a function of the operating parameter. The correction can then be determined, for example, by using a specific operating parameter as a standard and correcting the spectrum determined for other operating parameters to correspond to the standardized spectrum. At least one model that describes the functional relationship between the modification of the spectrum and / or spectroscopic information about the object and the operating parameter and / or describes the functional relationship between the correction required to correct the spectrum and / or spectroscopic information about the object and the operating parameter can be predetermined and, as an example, can be stored in at least one data storage device of the spectrometer device.

[0083] The detector may provide in step iii. at least one raw detector signal, wherein in step iv. the evaluation unit corrects the raw detector signal into at least one corrected detector signal by using the at least one selected correction information item.

[0084] As further outlined above, the evaluation unit can be configured to correct at least one detector signal by using a correction. Thus, as an example, the evaluation unit can be configured, for example by software programming, to convert the detector signal, in particular the raw detector signal (e.g., the spectrum derived therefrom), directly or indirectly, into a corrected detector signal, for example, into a corrected spectrum. As an example and as further outlined above, the correction can specifically include multiplying at least one detector signal (i.e., the "raw" detector signal or a secondary detector signal derived therefrom, for example, a spectrum generated by using the detector signal) by at least one correction factor. Thus, a correction of the spectrum can be performed that takes into account operating parameters as correction parameters. The evaluation unit can specifically be configured to use the corrected detector signal to obtain spectroscopic information.

[0085] As an example, the detector can be configured to generate detector signals for at least one spectral range of light from the object (specifically, for at least two different spectral ranges), specifically at least one of sequentially and simultaneously. For example, as outlined above, the detector can include an array of photosensitive elements, each of which can be sensitive to and / or exposed to light within a different spectral range. The evaluation unit can be configured to individually correct the detector signals for the different spectral ranges and to combine the individually corrected detector signals to obtain spectroscopic information. Thus, the individually corrected detector signals can be combined, for example, to generate a corrected spectrum.

[0086] Thus, in general, the detector may comprise an array of photosensitive elements, wherein each photosensitive element may be configured to generate at least one detector signal. The evaluation unit may generally be configured to individually correct each detector signal and to combine the detector signals to obtain the spectroscopic information. Thus, in particular, if each photosensitive element is sensitive to light in a different spectral range and / or is exposed to light in a different spectral range, for example via one or more suitable filters in the beam path of the detection light, the operating parameter may be individually corrected for each photosensitive element as an influence of the correction parameter.

[0087] As outlined above, the photosensitive elements can be sensitive to different spectral ranges of the light from the object. Different spectral sensitivities can be implemented by using photosensitive elements with inherently different spectral sensitivities, such as by using different integrated filters and / or different sensitive materials (e.g., semiconductor materials). Additionally or alternatively, different spectral sensitivities can be achieved by using one or more wavelength-selective elements (e.g., one or more filters, gratings, prisms, etc.) in one or more beam paths of the detection light, the one or more wavelength-selective elements being configured to allow different spectral portions of the detection light from the object to reach each photosensitive element sequentially or simultaneously.

[0088] The set of correction information items may be specific to at least one of:

[0089] A separate spectrometer device; or

[0090] Multiple spectrometer devices,

[0091] In particular, the set of correction information items is assigned to each spectrometer device according to its serial number. The set of correction information items can further be specific to individual detectors, in particular individual detectors in an individual detector array. Thus, an individual spectrometer device comprising an individual detector array having N detectors can include N separate sets of correction information items. Thus, spectrometer devices of the same type can use a separate set of correction information items. A first set of separate correction information items can be assigned to exactly one or more first spectrometer devices, and a second set of separate correction information items can be assigned to exactly one or more second spectrometer devices, wherein the first spectrometer device and the second spectrometer device can be of the same type and, in particular, can be identical in terms of their components, in particular in terms of the functionality and / or arrangement and / or type of the components. As used herein, the term "type" is a broad term and is to be given its ordinary and conventional meaning to a person of ordinary skill in the art and is not limited to a special or custom meaning. The term can specifically refer to, but is not limited to, components and / or spectrometers of the same series that deviate only in their functionality and / or structure due to inaccuracies in the manufacturing process. Thus, for a specific type of spectrometer device, multiple separate sets of correction information items may be used.

[0092] The evaluation unit may include a database having stored therein a plurality of correction information items (such as the set of correction information) as a function of the value of at least one different operating parameter. The database may include at least one lookup table specifically configured to provide the set of correction information items considered by the evaluation unit to obtain the spectroscopic information. As used herein, the term "database" is a broad term and is to be given its ordinary and conventional meaning for those skilled in the art and is not limited to a special or customized meaning. The term may specifically refer to, but is not limited to, an organized collection of data. The evaluation unit may include a data storage device on which the database may be stored. Alternatively or additionally, at least a portion of the database may be provided by a remote data storage device, such as a remote server, and / or an external data storage device. The database may be implemented as a lookup table and / or may include a lookup table. As used herein, the term "lookup table" is a broad term and is to be given its ordinary and conventional meaning for those skilled in the art and is not limited to a special or customized meaning. The term may specifically refer to, but is not limited to, replacing an array with simpler array indexing operations instead of runtime calculations. The lookup table may provide the required correction information items as correction information for the evaluation unit.

[0093] The at least one operating parameter comprises a set of at least two operating parameters.

[0094] The at least two operating parameters can be independently selected from the group consisting of: an input current applied to the light-emitting diode; a voltage applied to the light-emitting diode; an electrical power applied to the light-emitting diode; a forward voltage of the light-emitting diode; a forward current of the light-emitting diode; an ambient temperature; a temperature within the spectrometer device, in particular a temperature within at least one of the following: a light source, a drive unit, a detector or an evaluation unit; operating scheme parameters, in particular the number and / or sequence of measurements, a measurement duration, a duty cycle, parameters related to the operating scheme of the light source, parameters related to the operating parameters of the detector. The at least two operating parameters include at least one temperature (in particular at least one of the ambient temperature and a temperature within the spectrometer device), and at least one of an electrical operating parameter of the spectrometer device and an optical operating parameter of the spectrometer device. The at least two operating parameters can further include at least one operating scheme parameter. Additional and / or different operating scheme parameters as defined elsewhere herein can be considered.

[0095] As used herein, the term "forward voltage" is a broad term and is to be given its ordinary and customary meaning to those of ordinary skill in the art and is not limited to a special or customized meaning. The term may specifically, but is not limited to, refer to a voltage to be applied to an LED in the forward direction, i.e., by applying the positive contact of a voltage or current source to the p-layer of the LED and the negative contact to the n-layer of the LED, in order to generate a predetermined current through the LED. By way of example, the predetermined current defining the forward voltage may be a current known to generate a predetermined light output of the light source and / or light-emitting diode. The predetermined current may specifically be in the range of 10 mA to 500 mA, more specifically in the range of 50 mA to 300 mA. Additionally or alternatively, the term "forward voltage" may refer to the minimum voltage to be applied to an LED in the forward direction in order to generate a significant current through the LED, specifically a predetermined current defined as a minimum current, such as a current reaching and / or exceeding a minimum threshold. By way of example, the forward voltage may be a voltage that can be derived from the diode characteristics of an LED (i.e., from a graph indicating current as a function of voltage applied to the LED). As an example, the forward voltage can be obtained from a logarithmic plot of the diode characteristic of the LED, for example, by determining the inflection point in the forward branch of the characteristic, and / or by determining the voltage at the intersection of a straight line representing the steep portion of the forward branch with the horizontal or voltage axis. Thus, the forward voltage can generally represent the voltage that must be applied to the LED in the forward direction (p to n) in order to drive current (specifically forward current) through the diode. The forward voltage can depend on the band gap of the LED. Thus, in general, LEDs having a primary emission wavelength or range of primary emission wavelengths in the short wavelength range (such as in the blue spectrum) may typically require a higher forward voltage than LEDs emitting light in the longer wavelength range (such as red light). The forward voltage is sometimes also referred to as the "forward bias" or "junction voltage". For the forward voltage, the symbol or .

[0096] Thus, in general, the direction of current through an LED where the current flows from the p-doped layer to the n-doped layer of the LED, and / or the direction of current where the p-side or p-doped layer of the LED is connected to the positive connector of a power supply and where the n-side or n-doped layer of the LED is connected to the negative connector of the power supply can be identified as the "forward direction".

[0097] The measuring unit included in the drive unit can be configured to determine at least one actual value of at least one operating parameter. As used herein, the term "measuring unit" is a broad term and is to be given its ordinary and conventional meaning to those of ordinary skill in the art and is not limited to a special or customized meaning. The term can specifically refer to, but is not limited to, any device or combination of devices configured to measure one or more operating parameters. The measuring unit can include one or more measuring devices or measuring elements, such as one or more voltage measuring devices. As an example, the at least one actual value of the at least one operating parameter can be provided by the measuring unit in the form of at least one electrical signal and / or electrical information, which can include, for example, one or both of an analog signal and a digital signal. The electrical signal including the at least one actual value of the at least one operating parameter can be provided directly or indirectly to the evaluation unit. The electrical signal can be time-dependent or static. The measuring unit can be considered a functional part of the drive unit. However, the measuring unit can be included as a physical entity by the evaluation unit and / or the drive unit.

[0098] As used herein, term " operating scheme parameter " is a broad term, and will be given its common and conventional implication for those of ordinary skill in the art and is not limited to special or customized implication.This term specifically can refer to but is not limited to the parameter relevant to at least one step included in the step sequence of process.Can consider operating scheme parameter to come correction spectroscopy information when determining actual operating scheme parameter.Alternatively or additionally, can consider operating scheme parameter to come correction spectroscopy information at a later time than determining actual operating scheme parameter.Thus, can consider the operating scheme parameter that affects at least one subsequent measurement, particularly consider it as the correction information in at least one subsequent measurement.The operating scheme parameter of previous measurement can be considered to be the correction information in a back measurement.Thus, can consider the operating scheme parameter of previous measurement that has influence and / or may affect a back measurement, particularly consider it as the correction information in a back measurement.

[0099] The operating scheme parameters can be selected from at least one of the following: the number and / or sequence of measurements; the measurement duration; parameters related to the operating scheme of the light source, in particular parameters describing the mode of the light source, such as continuous wave mode, modulation mode and / or duty cycle mode; parameters related to the operating parameters of the detector, in particular parameters describing the mode of the detector, such as gain mode, dark current mode, and / or correction mode; voltage level of the internal power supply and / or external power supply of the spectrometer device; the operating load of the evaluation unit; power dissipation of the internal power supply and / or external power supply of the spectrometer device to the spectrometer device and at least one peripheral module (such as a camera), the at least one peripheral module being further connected to the internal power supply and / or external power supply of the spectrometer device; or wear and / or storage conditions of the spectrometer device.

[0100] The method can specifically be performed on-site, online. As used herein, the term "online" is a broad term and is to be given its ordinary and customary meaning for those skilled in the art and is not limited to a specific or customary meaning. The term can specifically refer to, but is not limited to, the following characteristics: a process is performed while another process is ongoing (e.g., during the other process), and preferably does not need to be separately started or initiated by a user. Thus, specifically, by taking into account at least one operating parameter, the correction of the detector signal can be performed as an online correction during the acquisition of spectroscopic information about at least one object.

[0101] The method can be at least partially computer-implemented. The method described above and / or according to any of the embodiments described in further detail below can be at least one of computer-controlled, computer-implemented, and computer-assisted, for example by using one or more computer programs running on at least one processor (e.g., at least one processor of a spectrometer device (e.g., at least one processor integrated in a detector and / or in an evaluation unit)). Specifically, as outlined above, at least step iv. of the method can be at least one of computer-controlled, computer-implemented, and computer-assisted. However, it should be noted that other steps of the method can also be at least one of computer-controlled, computer-implemented, and computer-assisted, for example, one or more of steps i., ii., and iii.

[0102] In another aspect, a calibration method for compiling a set of correction information items for use in a method for operating a spectrometer device for obtaining spectroscopic information about at least one object is disclosed. The calibration method comprises the following steps, which can be performed in a given order. However, a different order is also possible. In particular, one, more than one, or even all of the method steps can be performed once or repeatedly. Furthermore, the method steps can be performed sequentially, or alternatively, one or more method steps can be performed in a timely overlapping manner, or even in parallel, and / or in combination. The method may further include additional method steps not listed.

[0103] The calibration method includes the following steps:

[0104] I. performing a plurality of calibration measurements on the spectrometer device under different operating conditions, each calibration measurement comprising measuring a system response of the spectrometer device in a controlled environment, the system response comprising spectral information;

[0105] II. recording at least one value of the at least one operating parameter for each of the calibration measurements;

[0106] III. Compiling a set of correction information by comparing the spectral information with at least one recorded value of at least one operating parameter for each of these calibration measurements.

[0107] As used herein, the term "controlled environment" is a broad term and is to be given its ordinary and customary meaning to those skilled in the art and is not limited to a special or customized meaning. The term may specifically, but is not limited to, the surroundings and / or area of ​​a spectrometer device in which at least one parameter (such as at least one operating parameter) is at a known and / or predetermined (particularly standard) value, in particular by being controlled to assume a known and / or predetermined value. In a controlled environment, predetermined standard conditions, in particular standard conditions as defined elsewhere herein, may apply.

[0108] The calibration method may comprise performing calibration measurements under, in particular, these predetermined and controlled ambient conditions. Thus, in particular, the ambient temperature, i.e. the temperature within the spectrometer device, in particular the temperature within at least one of the lamp, the drive unit, the detector and / or the evaluation unit, may be controlled to assume predetermined values.

[0109] Step III. may include storing at least one of the emission spectrum, the correction function of the emission spectrum, or the correction factor of the emission spectrum in a lookup table. The calibration measurement may be performed at different ambient temperatures. Step I. may include using an external detector, specifically at least one of an external spectrometer and an external power meter. As used herein, the term "power meter" is a broad term and will be given its ordinary and conventional meaning to a person skilled in the art and will not be limited to a special or customized meaning. The term may specifically refer to, but is not limited to, a calibrated device capable of measuring spectral flux. In order to measure the spectral flux, the power meter may include at least one detector. The external power meter is a power meter that is not included in the spectrometer device. The calibration method may include using an external power meter having at least one wavelength selective element, specifically at least one of an optical filter, a dispersive element, and a diffraction element. As used herein, the term "wavelength selective element" is a broad term and will be given its ordinary and conventional meaning to a person skilled in the art and will not be limited to a special or customized meaning. The term may specifically refer to, but is not limited to, any optical element that interacts with different spectral portions of incident light in different ways, for example by having at least one wavelength-dependent optical property, such as at least one wavelength-dependent optical property selected from the list consisting of reflectivity, reflection direction, refraction, refraction direction, absorption, transmission, and refractive index.

[0110] Step I. may comprise using a light source of a spectrometer device and using at least one calibration target, in particular using at least one diffuse reflectance calibration target with known reflectance spectral characteristics, wherein step I. further comprises performing a plurality of spectral measurements using the light emitting diodes of the light source at a predetermined repetition rate, in particular at least 0.1 Hz, 0.5 Hz, 1 Hz, 2 Hz, 5 Hz or 10 Hz. As a result, the spectrometer device can be heated, in particular by heating the light source, more particularly by heating the light emitting diodes. The use of an external detector can ensure that the calibration can be independent of heating effects on the external detector, which is not heated by performing the above steps. In this way, it can be ensured that the external detector signal used for calibration is stable. Alternatively or additionally, the spectrometer device can be heated by performing continuous spectral measurements with a predetermined length. Typically, the continuous spectral measurements can have a predetermined length of at least 0.1 s, 0.5 s or 1 s.

[0111] Spectral measurements, in particular spectral measurements of at least one calibration target, can further be performed within a predetermined time span before the measurement for obtaining spectroscopic information about the object being analyzed. The predetermined time span can be at least 1 s, 5 s, or 10 s, 20 s, or 30 s long. Alternatively or additionally, the predetermined time span can be at least 5 min, or 10 min long. Alternatively or additionally, the spectrometer device can be heated when the spectrometer device and / or software related to the use of the spectrometer device can be started. At least one diffuse reflectance calibration target for determining at least one performance parameter related to the detector can be comprised by an integrating sphere, wherein the integrating sphere is configured for connecting the spectrometer device to an external detector and / or an external light source, for example by using at least one optical port.

[0112] Step II. may comprise recording at least two, in particular at least three, and more particularly all operating parameters of a list of operating parameters consisting of: an input current applied to the light emitting diode, a voltage applied to the light emitting diode, a forward voltage of the light emitting diode, and a forward current of the light emitting diode; operating scheme parameters, in particular as the number and / or sequence of measurements, the measurement duration, parameters related to the operating scheme of the light source, parameters related to the operating parameters of the detector; and wherein the calibration method further comprises recording at least one light signal, wherein the at least one light signal comprises at least one of a detector signal of a detector of the spectrometer device and a signal provided by an external detector, in particular an external power meter, and wherein step III. comprises deriving the correction information by taking into account the light signal. Additional and / or different operating scheme parameters as defined elsewhere herein may be taken into account.

[0113] Another correction information item for correcting at least one determined actual value of at least one operating parameter determined by the drive unit can be determined using an external measurement device, in particular, and step III. can include taking this other correction information item into account when compiling the set of correction information. In particular, the drive unit and / or the measuring unit can be calibrated thereby. The external measurement device can be at least one optical sensor configured to detect time-resolved spectral data. For example, an external optical sensor and / or a flux meter and / or an external spectrometer, in particular in combination with at least one static and / or at least one dynamic optical filter.

[0114] The light source may be driven in a predefined manner such that the temperature of the light source is set to a predefined value, in particular by taking into account the further correction information item and / or the thermal mass of the light source. As used herein, the term "driven in a predefined manner" is a broad term and is to be given its ordinary and conventional meaning to a person of ordinary skill in the art and is not limited to a special or customized meaning. The term may specifically refer to, but is not limited to, introducing a specific amount of energy into the light source to heat the light source.

[0115] Performing multiple calibration measurements at different operating conditions of the spectrometer apparatus in step I. can be performed by determining at least one performance parameter by at least one of the following: determining at least one performance parameter specifically related to the detector using an external light source, particularly one with a known emission spectrum; or determining at least one performance parameter specifically related to the detector using an external detector, particularly one with a known spectral efficiency; wherein the at least one performance parameter can be taken into account in compiling a set of calibration information in step III. As used herein, the term "performance parameter" is a broad term and is to be given its ordinary and customary meaning for those skilled in the art and is not limited to a specific or customary meaning. The term can specifically refer to, but is not limited to, a quantitative value representing a relationship, in particular, between an input and an output. The input can relate to at least one temperature, and the output can relate to at least one detector sensitivity, responsivity, and / or dark resistance. Alternatively or additionally, the input can relate to temperature, forward voltage, forward current, and / or electrical power, and the output can relate to spectral flux, a shift in at least one peak wavelength, a shift in at least one peak amplitude, or a shift in the total flux of the external light source. Thus, the performance parameter can specifically relate to an electrical value.

[0116] The calibration method can be repeated for another light source of the same type, wherein another set of correction information is compiled.Thus, spectrometer devices of the same type can use a separate set of correction information items.

[0117] In another aspect, a spectrometer apparatus for obtaining spectroscopic information about at least one object is disclosed. The spectrometer apparatus comprises:

[0118] A. at least one light source for generating illumination light for illuminating an object, the light source comprising at least one light-emitting diode and at least one luminescent material for light-converting primary light generated by the light-emitting diode;

[0119] B. at least one driving unit for driving the light source, the driving unit being configured to determine at least one actual value of at least one operating parameter of the spectrometer device;

[0120] C. at least one detector for detecting light from the object and for generating at least one detector signal; and

[0121] D. At least one evaluation unit for evaluating the detector signal and for deriving spectroscopic information about the object therefrom, the evaluation unit being configured for selecting at least one correction information item from a predetermined set of correction information items depending on the actual value of at least one operating parameter and for taking into account the selected correction information item to derive the spectroscopic information.

[0122] The light source may include a phosphor light emitting diode. The light emitting diode may specifically have a primary emission range that is at least partially within the spectral range of 250 nm to 940 nm. The light emitting diode may specifically have a primary emission range that is at least partially within the spectral range of 420 nm to 460 nm, more specifically within the range of 440 nm to 445 nm, more specifically at 440 nm.

[0123] The illumination light may have a spectral range which lies at least partially in the near infrared spectral range, in particular in the spectral range of 1 to 3 μm, preferably 1.3 to 2.5 μm, more preferably 1.5 to 2.2 μm.

[0124] In another aspect, a computer program is disclosed, comprising instructions that, when executed by the spectrometer device, cause the spectrometer device to perform a method for operating a spectrometer device. In another aspect, a computer-readable storage medium is disclosed, comprising instructions that, when executed by the spectrometer device, cause the spectrometer device to perform a method for operating a spectrometer device. In another aspect, a non-transitory computer-readable medium is disclosed, comprising instructions that, when executed by one or more processors of an evaluation unit of the spectrometer device, cause the one or more processors to perform the method for operating a spectrometer device.

[0125] As used herein, the terms "computer-readable data carrier," "computer-readable storage medium," and "non-transitory computer-readable medium" are broad terms and are to be given their ordinary and customary meanings to those skilled in the art and are not limited to special or customized meanings. These terms may specifically refer to, but are not limited to, data storage devices, particularly non-transitory data storage devices, such as hardware storage media having computer-executable instructions stored thereon. A computer-readable data carrier or storage medium or computer-readable medium may specifically be or include a storage medium such as a random access memory (RAM) and / or a read-only memory (ROM).

[0126] As used herein, the terms "having," "including," or "comprising," or any grammatical variations thereof, are used in a non-exclusive manner. Thus, these terms can refer to the absence of additional features in the entity described in that context, in addition to the features introduced by these terms, or the presence of one or more additional features. By way of example, the expressions "A has B," "A includes B," and "A contains B" can refer to the absence of any other elements in A besides B (i.e., A consists solely and solely of B), or the presence of one or more additional elements in entity A, such as element C, elements C and D, or even additional elements, in addition to B.

[0127] Furthermore, it should be noted that the terms "at least one", "one or more", or similar expressions indicating that a feature or element may occur once or more than once are typically used only once when introducing the corresponding feature or element. In most cases, when referring to the corresponding feature or element, the expression "at least one" or "one or more" is not repeated, although the corresponding feature or element may in fact occur once or more than once.

[0128] Further, as used herein, the terms "preferably", "more preferably", "particularly", "more particularly", "specifically", "more specifically" or similar terms are used in conjunction with optional features, without limiting the possibilities of alternatives. Therefore, the features introduced by these terms are optional features and are not intended to limit the scope of the claims in any way. As the skilled person will recognize, the present invention can be carried out through the use of alternative features. Similarly, features introduced by "in an 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 features introduced in this manner with other optional or non-optional features of the invention.

[0129] In one or more of the above-described embodiments and / or in one or more of the embodiments described in further detail below, the spectrometer device and method according to the present invention offer numerous advantages over known devices and methods of similar type. Specifically, online correction or calibration can be performed for temperature variations (even local temperature variations within the light source), which may affect the emission characteristics of the light source. More specifically, the operating parameters can provide reliable correction parameters, in particular when the ambient temperature is taken into account. Thus, fluctuations in the spectral flux of at least one light source and / or fluctuations (in particular, offsets) in the spectral characteristics of at least one light source can be compensated. By generating specific and / or individual, in particular serial number-specific, sets of correction information items, the accuracy and / or repeatability of the spectrometer measurements can be improved, in particular due to optimized corrections.

[0130] Furthermore, the use of phosphor LEDs instead of or in addition to conventional thermal emitters (such as incandescent lamps with a tungsten filament as light source) can provide several advantages. Thus, in general, even though thermal emitters can provide a flat spectrum, low temperature dependence and a high power spectral density even at long wavelengths (such as in the NIR range), thermal emitters are generally not well suited for high-volume spectrometer production. Thus, in general, disadvantages of thermal emitters include high complexity of the manufacturing process, low conversion efficiency of electrical power to optical power and physical limitations of miniaturization. These disadvantages can be overcome by using LEDs, in particular phosphor LEDs. LEDs have proven to be reliable light sources, such as standardized light sources in visible light schemes.

[0131] In the context of the present invention, a broadband light source can be provided by using one or more phosphor LEDs in a spectrometer device, the one or more phosphor LEDs comprising at least one light-emitting diode and at least one luminescent material or phosphor. Thus, as an example, a white light source and / or a broadband light source in the infrared range, in particular in the NIR range, can be generated. The phosphor can convert photons with a shorter wavelength and therefore higher energy into photons with a longer wavelength or lower energy, for example by transferring a portion of the primary photon energy to the phosphor material, such as to the phosphor lattice. The remaining lower energy can result in the emission of long-wavelength photons.

[0132] Thus, the luminescent material may be configured to absorb one or more primary photons generated by the light emitting diode and may emit one or more secondary photons in response to such absorption. The emission of the secondary photons may occur instantaneously or after a delay or decay time. Thus, as outlined above, the luminescent material may be or may include at least one of a phosphorescent material and a fluorescent material. The phosphorescence phenomenon may result in the following effect: after the primary light (such as a short wavelength or high energy pump light) is turned off, the luminescent material may emit a characteristic lifetime time. Secondary light (e.g., long-wavelength light) is emitted within the tau, for example, due to forbidden quantum optical transitions or forbidden dipole transitions. Thus, in particular, in luminescent materials, the emission of secondary light can occur via forbidden transitions (e.g., forbidden dipole transitions) that have a longer lifetime than, for example, spontaneous dipole-allowed transitions, as may be the case for many fluorescent materials.

[0133] In particular, as outlined above, a luminescent material, in particular a phosphorescent material, can be used that has absorption in the blue spectral range and emission in the infrared spectral range. By way of example, a luminescent material can be used that is capable of converting blue primary light or pump light having a wavelength of, for example, 440 nm into near-infrared secondary light (e.g., secondary light having a wavelength in the range of 1 to 3 µm, preferably 1.3 to 2.5 µm, and more preferably 1.5 to 2.2 µm). Additionally or alternatively, the primary light or pump light can be generated by an infrared LED having a wavelength in the range of 850 nm to 940 nm, which can then be converted by the luminescent material into near-infrared secondary light having a wavelength in the range of 1 to 3 µm, preferably 1.3 to 2.5 µm, and more preferably 1.5 to 2.2 µm.

[0134] A phosphor LED comprising at least one light emitting diode and at least one luminescent material may be implemented as a single component. Thus, on a technical level, a phosphor LED may comprise a plurality of subcomponents.

[0135] First, a phosphor LED may include one or more functional components, such as an LED die, including at least one junction, such as at least one pn junction, between at least two semiconductor regions. In the LED die, primary light, such as short-wavelength pump light, may be generated, for example, in the blue spectral range.

[0136] Further, a phosphor LED may include at least one luminescent material, in particular at least one phosphor material, which may in particular be placed directly on top of the LED die and may convert primary light, in particular pump light, into secondary light, in particular into long wavelength near-infrared light.

[0137] Furthermore, the phosphor LED may comprise one or more substrates, in particular one or more electrically insulating substrates. Thus, as an example, the phosphor LED may comprise one or more ceramic substrates. The at least one substrate may be configured to hold at least one LED die and at least one luminescent material. Furthermore, the at least one substrate may hold or comprise one or more electrical connection components, such as one or more contact pads and / or one or more electrical leads, such as one or more metal contacts and / or one or more metal leads. In addition, the substrate (such as a ceramic substrate) may be configured to act as a heat sink. For example, during the conversion process, heat may be generated in both the LED die and the luminescent material (such as due to the limited conversion of electrical energy into photon energy), as well as in the luminescent material. The heat may be dissipated in the substrate, such as in the ceramic substrate.

[0138] Spectrometer devices using at least one LED can be configured to apply a continuous wave (CW) mode and / or preferably at least one modulated drive scheme to improve measurement accuracy and reliability. Thus, for example, at least one driver unit can be configured to apply a modulated drive scheme to the LED, and the evaluation device can be configured to utilize the modulated drive scheme to derive at least one item of spectroscopic information from at least one detector signal. For example, phase-locking techniques, filtering techniques, etc., as known to those skilled in the art, can be applied.

[0139] Thus, the spectrometer apparatus may be configured to apply a modulated drive scheme to the LEDs to compensate for the detector's DC background and / or reduce detector noise.Thus, as an example, a bandpass filter may be applied to the detector signal in order to remove the DC component.

[0140] Illumination light generated by a light source (specifically, a phosphor LED) can be directed to illuminate the sample. For example, one or more mirrors can be used to direct the illumination light. Detection light (e.g., reflected light) from the object can be directed to a detector, optionally using one or more optical components. For example, one or more wavelength-selective elements, such as one or more dispersive elements, can be used to separate the detection light into its spectral components.

[0141] One or more detector signals can be recorded by the detector, for example, using readout electronics included in the spectrometer device. Specifically, the readout electronics can be included in one or both of the detector and the evaluation device. For example, the readout electronics can include one or more signal processing devices. Thus, as outlined above, for evaluation by the evaluation device, a "raw" detector signal and / or one or more secondary detector signals derived therefrom (e.g., one or more filtered detector signals) can be used. Furthermore, at least one detector signal (primary or secondary) can be combined with additional information (e.g., information about the wavelength), such as the number of the photosensor element in the photosensor array from which the detector signal was derived, which is known to have been exposed to a specific wavelength within a certain wavelength range. In the context of the present invention, specifically in the context of evaluating detector signals by an evaluation unit, the option of evaluating the raw detector signal and / or the option of evaluating the secondary detector signal (e.g., a preprocessed detector signal, a processed detector signal, or a combined detector signal) is possible. However, the present invention remains relevant, in particular, for correcting the "raw" detector signal (specifically, a detector signal indicating a variation in signal intensity with the detection wavelength). However, other options are possible.

[0142] As an example, the detector signal (e.g., by the detector itself and / or by the evaluation unit) can be processed or preprocessed into a secondary detector signal by applying one or more Fourier transforms. For example, a fast Fourier transform can be applied. Based on the processed secondary detector signal, at least one item of spectroscopic information can be derived, for example, by software executed by the evaluation unit. Thus, as an example, the Fourier transform of the detector signal can be read out by software of the spectroscopic device (specifically, the evaluation device) and post-processed into spectroscopic information about the object.

[0143] As outlined above, LEDs and phosphor LEDs can thus provide highly efficient light sources that can be modulated to implement specific evaluation scenarios and to reduce noise and artifacts. By using at least one item of information about an operating parameter as a correction or calibration parameter, temperature variations within the light source (specifically, within the LED) can be fully or partially compensated. Thus, for a typical LED as used herein, when operated at the maximum voltage and current the LED can withstand, the temperature of various components of the light source (specifically, the temperature of the LED) can vary over a wide temperature range. As an example, the standard operating current can range from 2 mA to 1000 mA, typically from 10 mA to 300 mA. As an example, the forward voltage can range from 1.5 V to 3.5 V, typically from 2.25 V to 3 V. Thus, as an example, under maximum operating conditions, the emitter junction temperature can range from 135°C. The operating case temperature can range from -40°C to 135°C, and the emitter storage temperature can range from -40°C to 125°C. According to the ANSI / ESDA / JEDEC JS-001-2012 standard, the ESD sensitivity of an LED can be 250 V. These typical parameters show a large temperature variation range, which may have an impact on the spectroscopic information obtained about the object by the spectrometer device. It should be noted that other parameters and other parameter ranges are also possible.

[0144] It is generally known that phosphor LEDs generate different spectra depending on the composition of the luminescent material (such as the phosphor). Typically, each phosphor LED has multiple peaks in its spectrum, which is typically distributed over a wide wavelength range. However, even when the same current is supplied to the phosphor LED, its spectral characteristics or spectrum may vary with temperature. These variations can include shifts in emission peaks, broadening or narrowing of the spectrum, increases or decreases in emission, and so on. However, in many cases, emission at some wavelengths is more significantly affected than at others. Therefore, within the spectrum, there is typically a specific central wavelength where the power (specifically, the power spectral density) generally does not vary with temperature. Therefore, each wavelength typically has its own temperature coefficient with respect to power increase / decrement. Consequently, the shape of the spectrum varies with temperature. By using operating parameters as correction parameters, individual temperature corrections can be performed on spectra at different wavelengths. Therefore, as outlined above, the evaluation unit can be configured to individually correct the detector signals in different spectral ranges and to combine these individually corrected detector signals to obtain spectroscopic information. More specifically, as also outlined above, such individual corrections can be performed using an array of photosensors, wherein each photosensor can be configured to generate at least one detector signal, and wherein each detector signal can be individually corrected using operating parameters as correction parameters. Finally, the corrected detector signals can be combined to obtain spectroscopic information.

[0145] By using the operation as a correction parameter, the temperature variation and individual characteristics of the phosphor LED can be corrected. Thus, as an example, when the same current is applied to the LED, the forward voltage of the LED will generally decrease as the temperature increases. Each type of LED has its own forward voltage-temperature characteristic curve. Generally, the forward voltage of an LED decreases linearly with increasing temperature, such as with to Slope in the range of V / K.

[0146] Furthermore, the spectrometer apparatus and method may take into account the characteristics of the luminescent material used in the light source. Thus, as outlined above, typically there is a delay between the absorption of at least one primary photon by the luminescent material and the emission of at least one secondary photon by the luminescent material. This delay may be represented by a so-called "characteristic time constant" (also known as "time constant," "decay time," or "saturation time"). As is well known to those skilled in the art, the term "time constant" is a broad term and is to be given its ordinary and customary meaning to those of ordinary skill in the art and is not limited to a special or customized meaning. When used in the context of processes where the rate or probability of a process (such as photon emission) is proportional to the population of one or more states or process states, that population typically varies exponentially. In these processes, the time constant The 1 / e time of the process can be determined. For luminescent materials or converters, particularly phosphors, two different time constants can occur. First, the first time constant can describe the typical time required to reach saturation of the converted light emission. Secondly, the second time constant can describe the typical duration of the afterglow of the luminescent material or converter.

[0147] Typical time constants for phosphor converters are in the range of 0.1 ms to <10 ms. These time constants often vary between different phosphor LEDs and / or between different types of luminescent materials or phosphors. Typically, phosphors emitting at shorter wavelengths exhibit shorter time constants. Additionally, the decay constant and the growth constant Can depend on wavelength. The time constant is usually extracted from the step response of the optical signal by applying / cutting off the forward current.

[0148] After the forward current is turned off, the signal or emission typically decays according to equation (1):

[0149] (1)

[0150] After the forward current is turned on, the signal or emission generally increases according to equation (2):

[0151] (2)

[0152] For equations (1) and (2), When the forward current is applied / cut off, The optical signal level at . for The optical signal level reached when

[0153] Another characteristic of LEDs is that their light output power varies with forward current. Therefore, generally, increasing the input current increases the LED's permissible power. The shape (e.g., slope) of the light output vs. forward current curve is characteristic of each LED.

[0154] As outlined above, the use of operating parameters as control or correction parameters for spectroscopic analysis purposes allows for efficient and reliable online correction or online calibration. Thereby, various challenges of typical spectrometers and their corresponding calibrations can be overcome. In particular, in a typical spectroscopic analysis process, a reference measurement of the spectrometer allows for calibration of the instrument response, so that the measurement only provides information about the sample. However, if the optical components of the spectrometer apparatus change between the reference measurement and the sample measurement, the sample information will be affected by the systematic changes, so that the information about the sample may be distorted. In particular, when the spectrum of the light source is In a reference measurement (during which the light source has a spectrum ) and the actual sample measurement (during which the light source has a spectrum ) between the two spectra, the spectroscopic information about the image or sample will be distorted because the spectrum is usually based on two spectra. 、 The situation is often even more complex in phosphor LEDs, as the spectrum of a phosphor LED is a combination of the spectrum of the LED and the spectrum of the luminescent material. Both components of a phosphor LED can be affected by temperature changes in different ways. Therefore, for phosphor LEDs, the spectrum can usually be described by equation (3):

[0155] (3)

[0156] in, Express the spectrum of the light source LS as wavelength , LED pn junction temperature and the temperature of the phosphor function. represents the spectrum of an LED (e.g. a blue LED), and Represents the spectrum of a luminescent material, such as a phosphor.

[0157] Both subcomponents, the LED and the luminescent material, exhibit separate temperature responses. Therefore, system temperature variations or offsets, or ambient temperature variations or offsets (particularly between reference and sample measurements), typically affect the spectrum by affecting both the LED junction and the luminescent material.

[0158] In summary, and without excluding further possible embodiments, the following embodiments may be envisaged:

[0159] Embodiment 1: A method of operating a spectrometer device for obtaining spectroscopic information about at least one object, the method comprising:

[0160] i. illuminating the object with illumination light generated by at least one light source of the spectrometer device, the light source comprising at least one light-emitting diode and at least one luminescent material for photoconverting the primary light generated by the light-emitting diode;

[0161] ii. determining at least one actual value of at least one operating parameter of the spectrometer device by using at least one drive unit of the spectrometer device, the drive unit being configured to electrically drive the light source;

[0162] iii. detecting detection light from the object using at least one detector of the spectrometer device and generating at least one detector signal; and

[0163] iv. deriving spectroscopic information about the object by evaluating the detector signal using at least one evaluation unit of the spectrometer device, the evaluation unit being configured for selecting at least one correction information item from a predetermined set of correction information items depending on the actual value of the at least one operating parameter and for taking into account the selected correction information item to derive the spectroscopic information.

[0164] Embodiment 2: The method according to the preceding embodiment, wherein the set of correction information items is specific to at least one of the following:

[0165] A separate spectrometer device; or

[0166] Multiple spectrometer devices,

[0167] In particular, the set of correction information items is assigned to each spectrometer device according to its serial number.

[0168] Embodiment 3: A method according to any one of the preceding embodiments, wherein the detector provides at least one raw detector signal in step iii., wherein, in step iv., the evaluation unit corrects the raw detector signal into at least one corrected detector signal by using the at least one selected correction information item.

[0169] Embodiment 4: The method according to any one of the preceding embodiments, the evaluation unit comprising a database having stored therein a plurality of correction information items as a function of the value of the at least one different operating parameter.

[0170] Embodiment 5: The method according to the preceding embodiment, wherein the database comprises at least one lookup table, which is specifically configured to provide the plurality of correction information items taken into account by the evaluation unit for deriving the spectroscopic information.

[0171] Embodiment 6: The method according to any one of the preceding embodiments, wherein the at least one operating parameter comprises a set of at least two operating parameters.

[0172] Embodiment 7: A method according to the previous embodiment, wherein the at least two operating parameters are independently selected from the group consisting of: an input current applied to the light-emitting diode; a voltage applied to the light-emitting diode; an electrical power applied to the light-emitting diode; a forward voltage of the light-emitting diode; a forward current of the light-emitting diode; an ambient temperature; a temperature within the spectrometer device, specifically a temperature within at least one of the following: the light source, the drive unit, the detector or the evaluation unit; operating scheme parameters, specifically the number and / or sequence of measurements, measurement duration, duty cycle, parameters related to the operating scheme of the light source, parameters related to the operating parameters of the detector.

[0173] Embodiment 8: The method according to any one of the first two embodiments, wherein the at least two operating parameters include at least one temperature (specifically at least one of the ambient temperature and the temperature inside the spectrometer device), and at least one of the electrical operating parameters of the spectrometer device and the optical operating parameters of the spectrometer device.

[0174] Embodiment 9: The method according to the previous embodiment, wherein the at least two operating parameters further include at least one operating scheme parameter.

[0175] Embodiment 10: The method according to any one of the preceding method embodiments, wherein the method is at least partially implemented by a computer.

[0176] Embodiment 11: A calibration method for compiling a set of correction information items for use in a method according to any one of the preceding embodiments, the calibration method comprising:

[0177] I. performing a plurality of calibration measurements on the spectrometer device under different operating conditions, each calibration measurement comprising measuring a system response of the spectrometer device in a controlled environment, the system response comprising spectral information;

[0178] II. recording at least one value of the at least one operating parameter for each of the calibration measurements;

[0179] III. Compiling a set of correction information by comparing the spectral information with the at least one recorded value of the at least one operating parameter for each of the calibration measurements.

[0180] Embodiment 12: The calibration method according to the preceding embodiment, comprising performing the calibration measurements under predetermined and controlled environmental conditions.

[0181] Embodiment 13: The calibration method according to any one of the two preceding embodiments, wherein step III. comprises storing at least one of the emission spectrum, the correction function of the emission spectrum, or the correction factor of the emission spectrum in a lookup table.

[0182] Embodiment 14: The calibration method according to any one of the preceding three embodiments, wherein the calibration measurements are performed at different ambient temperatures.

[0183] Embodiment 15: The calibration method according to any one of the preceding embodiments relating to calibration methods, wherein step I. comprises using an external detector, specifically at least one of an external spectrometer and an external power meter.

[0184] Embodiment 16: The calibration method according to the preceding embodiment, wherein the calibration method comprises using an external power meter having at least one wavelength selective element, specifically at least one of an optical filter, a dispersive element and a diffractive element.

[0185] Embodiment 17: A calibration method according to any one of the aforementioned embodiments relating to calibration methods, wherein step I. includes using the light source of the spectrometer device and using at least one calibration target, specifically using at least one diffuse reflectance calibration target with known reflectance spectral characteristics, wherein step I. further includes using the light-emitting diode of the light source to perform multiple spectral measurements at a predetermined repetition rate, specifically a repetition rate of at least 0.1 Hz, 0.5 Hz, 1 Hz, 2 Hz, 5 Hz or 10 Hz.

[0186] Embodiment 18: A calibration method according to any one of the aforementioned embodiments relating to a calibration method, wherein step II. includes recording at least two, specifically at least three, and more specifically all operating parameters in a list of operating parameters consisting of the following items: an input current applied to the light-emitting diode, a voltage applied to the light-emitting diode, a forward voltage of the light-emitting diode and a forward current of the light-emitting diode, operating scheme parameters (specifically as the number and / or sequence of measurements), measurement duration, parameters related to the operating scheme of the light source, parameters related to the operating parameters of the detector; and wherein the calibration method further includes recording at least one optical signal, wherein the at least one optical signal includes a detector signal of the detector of the spectrometer device and at least one of a signal provided by an external detector, specifically an external power meter, and wherein step III. includes obtaining the correction information by taking into account the optical signal.

[0187] Embodiment 19: A calibration method according to any of the preceding embodiments relating to a calibration method, wherein another correction information item for correcting at least one determined actual value of at least one operating parameter determined by the drive unit is determined by using an external measurement setting, and wherein step III. includes taking the another correction information item into account when compiling the set of correction information.

[0188] Embodiment 20: A calibration method according to any of the preceding embodiments relating to calibration methods, wherein the light source is driven in a predefined scheme in such a way that the temperature of the light source is set to a predefined value, in particular by taking into account the other correction information item and / or the thermal mass of the light source.

[0189] Embodiment 21: The calibration method according to any one of the preceding embodiments relating to the calibration method, wherein in step I., performing a plurality of calibration measurements under different operating conditions of the spectrometer device is performed by determining at least one performance parameter by at least one of the following operations:

[0190] using an external light source, in particular an external light source having a known emission spectrum, to specifically determine the at least one performance parameter associated with the detector; or

[0191] using an external detector, in particular an external detector having a known spectral efficiency, to specifically determine the at least one performance parameter associated with the detector;

[0192] Therein, in step III. a set of correction information is compiled taking into account the at least one performance parameter.

[0193] Embodiment 22: The calibration method according to any of the preceding embodiments relating to calibration methods, wherein the calibration method is repeated for another light source of the same type, wherein another set of correction information specific to the other light source is compiled.

[0194] Embodiment 23: A spectrometer device for obtaining spectroscopic information about at least one object, the spectrometer device comprising:

[0195] A. at least one light source for generating illumination light for illuminating an object, the light source comprising at least one light-emitting diode and at least one luminescent material for light-converting primary light generated by the light-emitting diode;

[0196] B. at least one driving unit for driving the light source, the driving unit being configured to determine at least one actual value of at least one operating parameter of the spectrometer device;

[0197] C. at least one detector for detecting light from the object and for generating at least one detector signal; and

[0198] D. At least one evaluation unit for evaluating the detector signal and for deriving therefrom spectroscopic information about the object, the evaluation unit being configured for selecting at least one correction information item from a predetermined set of correction information items depending on the actual value of the at least one operating parameter and for taking into account the selected correction information item to derive the spectroscopic information.

[0199] Embodiment 24: The spectrometer device according to the preceding embodiment, wherein the light source comprises a phosphor light emitting diode.

[0200] Embodiment 25: The spectrometer device according to any of the preceding embodiments relating to spectrometer devices, wherein the light-emitting diode has a primary emission range that is at least partially located in the spectral range of 420 nm to 460 nm, more specifically in the range of 440 nm to 455 nm, more specifically at 440 nm.

[0201] Embodiment 26: According to any of the preceding embodiments relating to spectrometer devices, the illumination light has a spectral range that is at least partially located in the near-infrared spectral range, specifically in the spectral range of 1 to 3 µm, preferably 1.3 to 2.5 µm, more preferably 1.5 to 2.2 µm.

[0202] Embodiment 27: A computer program comprising instructions which, when executed by a spectrometer device according to any one of the preceding embodiments relating to a spectrometer device, cause the spectrometer device to perform a method for operating a spectrometer device according to any one of the preceding embodiments relating to a method for operating a spectrometer device.

[0203] Embodiment 28: A computer-readable storage medium comprising instructions which, when executed by a spectrometer device according to any one of the aforementioned embodiments relating to a spectrometer device, cause the spectrometer device to perform a method for operating a spectrometer device according to any one of the aforementioned embodiments relating to a method for operating a spectrometer device.

[0204] Embodiment 29: A non-transitory computer-readable medium comprising instructions that, when executed by one or more processors of an evaluation unit of a spectrometer device according to any one of the aforementioned embodiments relating to a spectrometer device, cause the one or more processors to perform a method for operating a spectrometer device according to any one of the aforementioned embodiments relating to a method for operating a spectrometer device. BRIEF DESCRIPTION OF THE DRAWINGS

[0205] Additional optional features and embodiments will be disclosed in more detail in the subsequent embodiments, preferably in conjunction with the dependent claims. As will be appreciated by those skilled in the art, the respective optional features can be implemented independently and in any feasible combination. The scope of the present invention is not limited by the preferred embodiments. The embodiments are schematically depicted in the accompanying drawings. Identical reference numerals in these drawings represent identical or functionally equivalent elements.

[0206] In the attached figure:

[0207] Figure 1 A schematic overview of a spectrometer apparatus is shown;

[0208] Figure 2 shows a schematic cross-sectional view of a light source;

[0209] Figure 3 shows a schematic flow chart illustrating the generation and processing of detector signals;

[0210] Figure 4 shows a graph representing an overlay of infrared radiation spectra of a phosphor LED at various temperatures;

[0211] Figure 5 shows a graph representing the variation of transmitted power as a function of temperature for a selected number of wavelengths;

[0212] Figure 6 shows a graph of the forward voltage versus temperature for a selected current;

[0213] Figure 7A and Figure 7B The spectra of two different types of phosphor LEDs are shown;

[0214] Figure 8A and Figure 8B The attenuation constant ( Figure 8A ) and the growth constant ( Figure 8B )

[0215] Figure 9A and Figure 9B The attenuation constant ( Figure 9A ) and the growth constant ( Figure 9B )

[0216] Figure 10 shows a graph representing normalized light output as a function of forward current;

[0217] Figure 11A method of operating a spectrometer device for obtaining spectroscopic information about at least one object is shown;

[0218] Figure 12 A calibration method is shown for compiling a set of correction information items; and

[0219] Figure 13 An exemplary calibration setup is shown. DETAILED DESCRIPTION

[0220] exist Figure 1 , a schematic overview of a spectrometer device 110 for obtaining spectroscopic information about at least one object 112 is shown. The spectrometer device 110 may comprise Figure 1 The following will refer to the multiple components shown. Figure 1 Possible components of a spectrometer device 110 and their interactions are described. Spectrometer device 110 includes at least one light source 114 for generating illumination light 116 for illuminating an object 112. Light source 114 can be at least one of a tunable light source, a light source having at least one fixed emission wavelength, and a broadband light source. Light source 114 can specifically be or include at least one electric light source. Light source 114 includes at least one light-emitting diode 118 and at least one luminescent material 120 for photoconverting primary light generated by light-emitting diode 118. By way of example, light-emitting diode 118 can include one or more of the following: a light-emitting diode (LED) based on spontaneous optical emission, a light-emitting diode (sLED) based on superluminescent emission, or a laser diode (LLED).

[0221] LED 118 may specifically include at least two semiconductor material layers 121, wherein light may be generated at at least one interface between the at least two semiconductor material layers 121, specifically due to the recombination of positive and negative charges. The at least two semiconductor material layers 121 may have different electrical properties, such as at least one of the layers being an n-doped semiconductor material 121 and at least one of the layers being a p-doped semiconductor material 121. Thus, as an example, LED 118 may include at least one pn junction and / or at least one pin structure. However, it should be noted that other device structures are also possible.

[0222] The light-emitting diodes 118 can generate primary light, which can also be referred to as "pump light." The primary light can then be converted into "secondary light," for example, using light conversion (e.g., by one or more luminescent materials 120, such as phosphor materials). Thus, at least one luminescent material 120 can form at least one converter (also referred to as a light converter) that converts the primary light into secondary light having different spectral characteristics than the primary light. Specifically, the spectral width of the secondary light can be greater than the spectral width of the primary light, and / or the emission center of the secondary light can be offset (specifically, red-shifted) compared to the primary light. Specifically, the at least one luminescent material 120 can have an absorptive property in the ultraviolet and / or blue spectral ranges, and an emissive property in the near-infrared and / or infrared spectral ranges. The illumination light 116 can be or include at least one of the primary light or a portion thereof, the secondary light or a portion thereof, or a mixture of the primary light and the secondary light.

[0223] like Figure 1 As indicated, the light source 114 may specifically include a phosphor light emitting diode 122, also referred to as a phosphor LED 122. The phosphor LED 122 may be a combination of at least one light emitting diode 118 configured to generate primary light or pump light and at least one luminescent material 120 (also referred to as a "phosphor") configured to photoconvert the primary light generated by the light emitting diode 118. The phosphor LED 122 may form a packaged LED light source including an LED die 124 (e.g., a blue LED emitting blue pump light) and a phosphor that, for example, fully or partially coats the LED 118 and, as an example, is configured to convert the primary light or blue light into light having different spectral characteristics (specifically, into near-infrared light). Figure 2 A more detailed view of the light source 114 implemented as a phosphor LED 122 is shown.

[0224] Generally, the light source 114 can be implemented in various ways. Thus, the light source 114 can be, for example, a part of the spectrometer device 110 in the housing 126 of the spectrometer device 110, such as Figure 1 However, alternatively or additionally, the at least one light source 114 can also be arranged outside the housing 126, for example as a separate light source 114 (not shown). The light source 114 can be arranged separately from the object 110 and illuminate the object 110 from a distance, such as Figure 1 As indicated.

[0225] Illumination light 116, as generated by light source 114, may propagate from light source 114 to object 112. Figure 1, illumination light 116 generated by a light source 114 and propagating to an object 112 is illustrated by an arrow. Specifically, the object 112 may include at least one sample that may be analyzed completely or partially by spectroscopic methods.

[0226] As from Figure 1 As apparent in FIG, the spectrometer device 110 further includes at least one detector 128 configured to detect detection light 130 from the object 112. The light propagating from the light source 114 to the object 112 may be referred to as illumination light 116, while the light propagating from the object 112 to the detector 128 may be referred to as “detection light” 130. Figure 1 , detection light 130 is indicated by an arrow. Detection light 130 may include at least one of the following: illumination light 116 reflected by object 112, illumination light 116 scattered by object 112, illumination light 116 transmitted by object 112, or luminescent light generated by object 112 (e.g., phosphorescence or fluorescence generated by object 112 after object 112 is optically, electrically, or acoustically excited by illumination light 116). Therefore, detection light 130 may be generated directly or indirectly by illumination light 116 irradiating object 112.

[0227] Detector 128 may be or include at least one optical detector 132. Optical detector 132 may be configured to determine at least one optical parameter, such as the intensity and / or power of light irradiating at least one sensitive area of ​​detector 132. More specifically, optical detector 132 may include at least one photosensor and / or at least one optical sensor, such as at least one of a photodiode, a photocell, a photoresistor, a phototransistor, a thermopile sensor, a photoacoustic sensor, a pyroelectric sensor, a photomultiplier, and a bolometer. Thus, detector 128 may be configured to generate at least one detector signal, more specifically at least one electrical detector signal in the aforementioned sense, that provides information about at least one optical parameter, such as the power and / or intensity of light irradiating detector 128 or a sensitive area of ​​detector 128.

[0228] Detector 128 may include a single optically sensitive element or region or a plurality of optically sensitive elements or regions. Figure 1 As indicated, detector 130 may include at least one detector array, more specifically an array of photosensitive elements 134. Each photosensitive element 134 may be configured to generate at least one detector signal. In particular, each photosensitive element 134 may include at least a photosensitive area that may be adapted to generate an electrical signal depending on the intensity of incident light, wherein the electrical signal may in particular be provided to an evaluation unit 136 of the spectrometer device, as will be further detailed below.

[0229] In the case where detector 128 comprises an array of optically sensitive elements 134, detector 128 can, for example, be selected from any known pixel sensor, in particular from a CCD chip or a CMOS chip. Alternatively, detector 128 can generally be or include a photoconductor, in particular an inorganic photoconductor, especially PbS, PbSe, Ge, InGaAs, extended InGaAs, InSb, or HgCdTe. As another alternative, the detector can include at least one of a pyroelectric element, a bolometer element, or a thermopile detector element.

[0230] The spectrometer device 110 comprises at least one evaluation unit 136 for evaluating at least one detector signal generated by the detector 128 and for deriving spectroscopic information about the object 112 from the detector signal. The detector 128 can directly or indirectly provide the detector signal to the evaluation unit 136. Thus, the detector 128 and the evaluation unit 136 can be directly or indirectly connected, e.g. Figure 1 The detector signal can be used as a "raw" detector signal and / or can be processed or pre-processed (e.g., by filtering, etc.) before further use. Thus, the detector 128 can include at least one processing device and / or at least one pre-processing device, such as at least one of an amplifier, an analog / digital converter, an electrical filter, and a Fourier transform.

[0231] At least one evaluation unit 136 is configured to evaluate the detector signal and to derive spectroscopic information about the object therefrom. The evaluation unit 136 is further configured to select at least one correction information item from a predetermined set of correction information items as a function of the actual value of at least one operating parameter, and to take into account the selected correction information item to derive the spectroscopic information.

[0232] like Figure 1 As shown, the spectrometer device 110 further comprises at least one driving unit 138 for electrically driving the light source 114. The spectrometer device 110 comprises at least one measuring unit 139. The measuring unit 139 is configured to generate at least one information item about at least one operating parameter (in particular the forward voltage) required to drive the light emitting diode 118. The measuring unit 139 may be a component of the driving unit 138, such as Figure 1as indicated. In particular, the driving unit 138 may be configured to provide a current to the LED 118, specifically to control the current through the LED 118. Therein, as an example, the driving unit 138 may be configured to adapt and measure a voltage provided to the LED 118, which voltage is required to achieve a specific current through the LED 118. The driving unit 138 may specifically include one or more of the following: a current source 140, a voltage source, a current measuring device (such as an ammeter), a voltage measuring device 142 (such as a voltmeter), a power measuring device. In particular, the driving unit 138 may include at least one current source 140 for providing at least one predetermined current to the LED 118, wherein the current source 140 may specifically be configured to adjust or control the voltage applied to the LED 118 so as to generate the predetermined current. As an example, the driving unit 138 may include one or more electrical components (such as integrated circuits) for driving the light source 114. The driving unit 138 may be fully or partially integrated into the light source 114, or may be separate from the light source 114, the latter configuration being preferred. Figure 1 In display.

[0233] As outlined above, the driving unit 138 is configured to generate at least one item of information about at least one operating parameter (in particular, a forward voltage) required to drive the light-emitting diode 118. The forward voltage can be applied to the LED in the forward direction, i.e., the positive contact of the voltage or current source 140 is applied to the p-layer of the LED 118 and the negative contact is applied to the n-layer of the LED 118, so as to generate a predetermined current through the LED 118. As an example, the predetermined current defining the forward voltage can be a current that is known to generate a predetermined light output of the light source 114 and / or the light-emitting diode 118.

[0234] To generate at least one item of information about at least one operating parameter (particularly a forward voltage) required for driving light-emitting diode 118 (e.g., driving LED 118 in the forward direction at a predetermined current), measurement unit 139 may include one or more measuring devices or measuring elements, such as one or more voltage measuring devices 142. By way of example, the at least one item of information about the at least one operating parameter may be provided by measurement unit 139 in the form of at least one electrical signal and / or electrical information, such as one or both of an analog signal and a digital signal. The electrical signal including the at least one item of information about the at least one operating parameter may be provided directly or indirectly to evaluation unit 136. The electrical signal may be time-dependent or static.

[0235] As outlined above, and as Figure 1As shown, the spectrometer device 110 includes at least one evaluation unit 136 for evaluating at least one detector signal generated by the detector 128 and for deriving spectroscopic information about the object 112 from the detector signal. The evaluation unit 136 is configured to take into account information items about at least one operating parameter when deriving the spectroscopic information from the detector signal. Specifically, the evaluation unit 136 can be configured to process at least one input signal and generate at least one output signal thereof. As an example, the at least one input signal can include at least one detector signal provided directly or indirectly by the at least one detector 128 and at least one signal provided directly or indirectly by the measuring unit 139, which signal includes at least one information item about the at least one operating parameter. Figure 1 The drive unit 138 (which includes Figure 1 The arrows between the measuring unit 139 and the evaluation unit 136 in the illustrated embodiment illustrate the provision of a signal to the evaluation unit 136 and / or the retrieval of a signal by the evaluation unit 136 , the signal comprising at least one item of information about at least one operating parameter.

[0236] The evaluation unit 136 may be or may include one or more integrated circuits (e.g., one or more application-specific integrated circuits (ASICs)) and / or one or more data processing devices 144 (e.g., one or more computers, digital signal processors (DSPs), field-programmable gate arrays (FPGAs)), preferably one or more microcomputers and / or microcontrollers. Additional components may be included, such as one or more pre-processing devices 146 and / or data acquisition devices, such as one or more devices for receiving and / or pre-processing detector signals, such as one or more A / D converters and / or one or more filters. Furthermore, the evaluation unit may include one or more data storage devices 148, such as Figure 1 Furthermore, the evaluation unit 136 may include one or more interfaces, such as one or more wireless interfaces and / or one or more wired interfaces.

[0237] Specifically, the evaluation unit 136 can be configured, for example, by software programming, to determine at least one correction based on information items about at least one operating parameter, specifically a correction based on a model describing a functional relationship between the spectral characteristics of the light source 114 and the at least one operating parameter. The evaluation unit 136 can further be configured to correct the at least one detector signal by using the correction. As described in detail above and as will be further described below in an exemplary manner, the correction can specifically include multiplying the at least one detector signal by at least one correction factor. The evaluation unit 136 can specifically be configured to use the corrected detector signal to obtain spectroscopic information.

[0238] As described in more detail above, the detector 128 can specifically include an array of photosensitive elements 134. Each photosensitive element can be configured to generate at least one detector signal. The evaluation unit 136 can be configured to individually correct each detector signal and to combine the detector signals to obtain spectroscopic information. The spectrometer device 110 can be configured such that the photosensitive elements of the detector 128 are sensitive to different spectral ranges of the light from the object 112. In particular, the detector 128 can be configured to generate detector signals for at least two different spectral ranges of the light from the object, specifically in a manner at least one of sequential and simultaneous. The spectrometer 110 can specifically include at least one filter element 150 arranged in the beam path of the light from the object. The filter element 150 can specifically be configured such that each photosensitive element is exposed to a separate spectral range of the light from the object 112.

[0239] The spectrometer device 110 may further include one or more optical components 151, such as one or more of at least one mirror, at least one lens, at least one aperture, and at least one wavelength selective element 152. Specifically, the one or more optical components 151 may be arranged in at least one of the beam path of the illumination light 116 and the beam path of the detection light 130. The spectrometer device 110 may particularly include at least one wavelength selective element 152. The wavelength selective element 152 may be selected from the group consisting of a tunable wavelength selective element 152 and a wavelength selective element 152 with a fixed transmission spectrum. By way of example, a tunable wavelength selective element 152 allows for sequential selection of different wavelength ranges, while a wavelength selective element 152 with a fixed transmission spectrum allows for a fixed wavelength range selection, or may also depend on, for example, the detector position. The wavelength selective element 152 may be used to separate incident light into a spectrum of component wavelength signals, the respective intensities of which are determined using a detector (such as the detector 128 of the spectrometer device 110, which may include an array of photosensors 134). The at least one wavelength selection element 152 may include, for example, at least one of a filter, a grating, and a prism. The wavelength selection element 152 may specifically include at least one of a wavelength selection element 152 disposed in the beam path of the illumination light 116 and a wavelength selection element 152 disposed in the beam path of the detection light 130. Figure 1 An embodiment of a spectrometer device 110 is shown having one wavelength selective element 152 arranged in the beam path of the illumination light 116 and one wavelength selective element 152 arranged in the beam path of the detection light 130 .

[0240] like Figure 1The spectrometer device 110, schematically shown in FIG. 1 , is configured to obtain spectroscopic information about at least one object 112. Specifically, the spectrometer device may be configured to obtain, for example, an item of information about the at least one object and / or radiation emitted by the at least one object, the information item characterizing at least one optical property of the object, more specifically, at least one item of information characterizing, for example, at least one of the transmission, absorption, reflection, and emission of the at least one object qualitatively and / or quantitatively. By way of example, the at least one spectral information item may include at least one item of intensity information, such as information about the intensity of at least one of light transmitted, absorbed, reflected, or emitted by the object, for example, as a function of wavelength or a wavelength subrange within one or more wavelengths (e.g., within a wavelength range). Thus, the spectrometer device 110 may be configured to acquire at least one spectrum, or at least a portion of a spectrum, of detection light 130 propagating from the object 112 to the detector 128. The spectrum may describe a radiometric measurement of the spectral flux, for example, given in watts per nanometer (W / nm), or other units, for example, as a function of the wavelength of the detection light. Thus, the spectrum may describe the optical power of light within a specific wavelength band, for example, within the NIR spectral range. A spectrum may include one or more optical variables that vary with wavelength, such as power spectral density, an electrical signal obtained by optical measurement, etc. Examples of spectra are Figure 4 、 Figure 7A and Figure 7B The spectrometer device 110 may specifically be a portable spectrometer device 110 , which may in particular be used on site.

[0241] exist Figure 2 A schematic cross-sectional view of a light source 114 is shown in FIG. The at least one light source 114 of the spectrometer device 110 can be configured to generate or provide electromagnetic radiation in one or more of the infrared, visible, and ultraviolet spectral ranges. Because many material properties or chemical composition characteristics of many objects 112 can be derived from the near-infrared spectral range, light typically used for the purposes of the present invention is light in the infrared (IR) spectral range, more preferably in the near-infrared (NIR) and / or mid-infrared (MidIR) spectral ranges, particularly light with a wavelength of 1 to 5 µm, preferably 1 to 3 µm. The light source 114 includes at least one light-emitting diode 118 and at least one luminescent material 120 for photoconverting the primary light generated by the light-emitting diode 118. As described above, the LED 118 and the luminescent material 120 together can form a phosphor LED 122.

[0242] like Figure 2As shown, the phosphor LED 122 may include one or more functional components. Specifically, the phosphor LED 122 may include one or more substrates 154, specifically one or more electrically insulating substrates 154. In particular, the phosphor LED 122 may include one or more ceramic substrates 156, such as Figure 2 As shown. The substrate 154 can be configured to hold at least one LED die 124 and at least one luminescent material 120. Further, at least one substrate 154 can hold or include one or more electrical connection components, such as Figure 2 One or more contact pads 158 and / or one or more electrical leads, such as one or more metal contacts and / or one or more metal leads, are shown. The substrate 154 can be configured to act as a heat sink. For example, during the conversion process, heat can be generated in the LED die 124 (e.g., due to the finite conversion of electrical energy to photon energy) and in the luminescent material 120. The heat can be dissipated in the substrate 154, such as a ceramic substrate.

[0243] like Figure 2 As shown, the phosphor LED 122 may include a light emitting diode 118. The light emitting diode 118 may be configured to use Figure 2 The at least one LED chip and / or at least one LED die 124 shown converts electric current into primary light, such as blue primary light. In particular, a pn junction diode can be used. As an example, one or more LEDs 118 selected from the group consisting of an indium gallium nitride (InGaN)-based LED 118, a GaN-based LED 118, an InGaN / GaN alloy-based LED 118, or a combination thereof, and / or other LEDs 118 can be used. Additionally or alternatively, quantum well LEDs 118 can also be used, such as one or more quantum well LEDs 118 based on InGaN. Additionally or alternatively, superluminescent LEDs (sLEDs) and / or quantum cascade lasers can be used. As described in Figure 2 As will be further apparent from the above, the phosphor LED may include at least one luminescent material 120 configured to light-convert the primary light generated by the light-emitting diode 118. Various types of conversion and / or luminescence are known and may be used in the context of the present invention. Specifically, the luminescent material 120 may include at least one of the following: cerium-doped YAG (YAG:Ce 3+ or Y3Al5O 12 :Ce 3+ ); rare earth-doped Sialon; copper and aluminum co-doped zinc sulfide (ZnS:Cu,Al).

[0244] The luminescent material 120 may in particular form at least one layer. In general, various alternatives for positioning the luminescent material 120 relative to the light-emitting diode 118 are feasible, which may be used individually or in combination. Firstly, the luminescent material 120 (e.g. at least one layer of the luminescent material 120, such as a phosphor) may be positioned directly on the light-emitting diode 118, e.g. with no material between the LED 118 and the luminescent material 120, or with one or more transparent materials in between, such as one or more transparent materials (in particular transparent for the primary light) between the LED and the luminescent material 120. Thus, as an example, a coating of the luminescent material 120 may be placed directly or indirectly on the LED 118 (not shown). Additionally or alternatively, as an example, the luminescent material 120 may form at least one converter 160, such as at least one converter disc, which may also be referred to as a converter sheet. The converter 160 may be placed on top of the LED 118, e.g. as Figure 2 As shown, the converter 160 is attached to the LED 118 with an adhesive. Additionally or alternatively, the luminescent material 120 can be remotely positioned, such that the primary light from the LED 118 must traverse an intermediate light path before reaching the luminescent material 120 (not shown). Again, by way of example, the remotely positioned luminescent material can form a solid or converter 160, such as a disk or converter disk. One or more optical elements, such as one or more lenses, prisms, gratings, mirrors, apertures, or combinations thereof, can be positioned in the intermediate light path. Thus, in particular, an optical system with imaging properties can be positioned in the intermediate light path, between the LED 118 and the luminescent material 120. Thus, by way of example, the primary light can be focused or concentrated onto the converter 160.

[0245] In the light source 114 (specifically, the phosphor LED 122), at least one luminescent material 120 can be positioned relative to the light emitting diode 118 such that heat can be transferred from the light emitting diode 118 to the luminescent material 120. More specifically, the luminescent material 120 can be positioned such that heat can be transferred by one or both of thermal radiation and thermal conduction (more preferably by thermal conduction). Thus, as an example, the luminescent material 120 can be in thermal contact and / or physical contact with the light emitting diode 118, such as Figure 2 Thus, generally, the temperature of the light emitting material 120 and the temperature of the light emitting diode 118 can be coupled.

[0246] like Figure 2As shown, the light source 114 (specifically, the phosphor LED 122) can include additional components, such as at least one side coating 162 that covers at least one side (e.g., a top side, a bottom side, and / or one or more lateral sides) of at least one of the following: the substrate 154, the contact pads 158, the light emitting diode 118, and the luminescent material 120. In particular, the side coating 162 can cover voids and / or gaps that may be present in the layered arrangement of the light source 114, such as Figure 2 As shown. Other components of the light source 114 (specifically Figure 2 Typically, the light source 114 (particularly the phosphor LED 122) can be packaged in a housing ( Figure 2 Thus, the LED 118 and the at least one luminescent material 120 for light conversion of the primary light generated by the light emitting diode 118 can be accommodated in a common housing. Alternatively, however, the LED 118 can also be a housingless or bare LED 118, such as Figure 2 What is shown.

[0247] Figure 3 The schematic flow chart of FIG. 1 shows the process of generating a detector signal and processing the detector signal to generate a corrected signal, for example. Figure 3 , hardware components 164 that may participate in this process or in the generation and / or preprocessing of the detector signal, as well as software components 166 that may participate in the processing and / or correction of the detector signal, are shown. Hardware components 164 (also referred to simply as "hardware" 164) may specifically include at least one light-emitting diode 118 (particularly a blue LED 118) of the spectrometer device 110 configured to emit blue primary light. Hardware components 164 may further include a luminescent material 120 (also referred to as an LED phosphor), an object 112, and one or more optical components 151 (e.g., at least one wavelength-selective element 152), and a detector 128.

[0248] As part of the corrections that can be performed by the evaluation unit 136, corrections can be performed for temperature changes (even for local temperature changes within the light source 114), which may have an influence on the emission characteristics of the light source 114. Figure 3, the temperature of the selected hardware component 164 is indicated in FIG. For example, depending on the arrangement of the hardware component 164 (such as the relative position and distance of the hardware component in the spectrometer device 110), the hardware component 164 may have different or the same temperature. Specifically, as described above, the temperature of the luminescent material 120 and the temperature of the luminescent diode 118 may be coupled, for example, due to heat transfer caused by one or both of thermal radiation and thermal conduction between the LED 118 and the luminescent material 120. Therefore, in particular, the temperature of the LED 118 (also referred to as "T pn ”) and the temperature of the luminescent material 120 (also referred to as “T Ph ”) can be similar or even identical. Figure 3 In FIG. 1 , the temperature of the LED 118 is indicated by reference numeral 168, the temperature of the luminescent material 120 is indicated by reference numeral 170, and the temperature of the detector 128 (also referred to as “T D ”) is indicated by reference numeral 172.

[0249] When current flows through the LED 118 (eg, due to the driver unit 138 applying an appropriate voltage to the LED), the LED 118 may emit primary light so as to generate a specific current (eg, a predetermined current). Figure 3 The target signal S indicated by reference numeral 174 in FIG. t , to drive LED 118 to emit blue primary light. In particular, the target signal S t Reference numeral 174 may be a predetermined current value to be generated through the LED 118, for example, by applying an appropriate voltage. Specifically, the predetermined current value may be in the range of 10 mA to 500 mA, more specifically in the range of 100 mA to 300 mA, for example, a current value of 50 mA. Thus, it is known that the predetermined current may generate a predetermined light output of the LED 118, such as a blue primary light. The LED 118 may be at a temperature "T" indicated by reference numeral 168. pn The blue primary light may be converted by the luminescent material 120 into secondary light, for example into light in the infrared spectral range. The luminescent material 120 may be at a temperature “T” indicated by reference numeral 170. ph”. The object 112 may be illuminated by illumination light 116 generated by the light source 114, which illumination light may include at least one of primary light or a portion thereof, secondary light or a portion thereof, or a mixture of primary light and secondary light. In order to guide the illumination light 116, one or more optical components 151 (such as one or more mirrors, lenses, wavelength selection elements 152 or other optical components 151) may be used, for example by placing the optical component 151 in the beam path of the illumination light 116. Detection light from the object 112 (such as reflected light) may be guided to the detector 128. In the beam path of the detection light 130, one or more optical components 151 may also optionally be used. As an example, one or more wavelength selection elements 152, such as one or more dispersive elements, may be used, for example to separate the detection light 130 into its spectral components.

[0250] As described in more detail above, the detector 128 may, for example, include an array of photosensitive elements 134. Specifically, the detector 128 may be or may include a pixel sensor, such as a CCD chip or a CMOS chip, which includes a plurality of pixels arranged on the chip. As an example, each pixel may correspond to a predetermined spectral range, for example, by being sensitive to the predetermined spectral range. Thus, the detector 128 may generate a detector signal S px,i 176, such as Figure 3 As indicated by reference numeral 176 in the diagram, the detector signal comprises a plurality of detector signals. Thus, each of the plurality of detector signals may correspond to an electronic signal generated by one of the plurality of pixels of the detector 128. Each of the plurality of detector signals may be given, for example, as a numerical value corresponding to the number of counts of the corresponding pixel measured, for example, during a predetermined time span. Thus, the detector signal S px,i 176 may specifically be a function of the wavelength of the detection light 130, as indicated by the index "px". px,i 176 may further be a function of time (eg in the case of a time-dependent detector signal), as indicated by the index "i".

[0251] Detector signal S px,i The multiple signals included in 176 can be generated simultaneously or in a temporally continuous manner. px、i 176 can be used as Figure 3 The detector signal S is determined by the readout electronics 178 shown. px、i 176 can be processed, for example, as part of pre-processing and / or as part of a further processing step. As an example, the pixels comprised by the detector 128 can specifically be active pixel sensors that can be adapted to amplify the electronic detector signal S px,i176 , for example as part of a pre-processing process prior to further processing that may be performed, for example, by one or more of the software components 166 .

[0252] The signal S generated by the detector 128 px,i 176 may also be referred to as "frame signal S px,i 176". Figure 3 The provision of a signal S to one of the software components 166 is shown by an arrow. px,i 176 process. Specifically, it is configured to process and / or correct the detector signal S px,i The software component 166 of 176 may include at least one first software 180 (also referred to as “software 1”) and at least one second software 182 (also referred to as “software 2”). The first software 180 may be configured to detect the detector signal S px,i 176 performs at least one first processing step 184 (also referred to as “processing 1”), for example by applying at least one algorithm to the detector signal S px,i 176. In particular, the first processing step 184 may comprise at least one correction for transient effects or time-dependent effects. Thus, as an example, the first processing step 184 may comprise one or more of: a correction for a dark signal; a correction for a dark signal drift; a correction for fluctuation effects; a correction for the photodetector response of individual detector elements or individual time steps; a correction for environmentally induced (e.g. temperature induced) variations in the photodetector response; extracting information for subsequent processing; an addition or multiplication with a parameter, the addition or multiplication being generated based on information about at least one operating parameter or about the temperature of the device. The first software 180 may be configured to perform at least one further step comprising performing at least one fast Fourier transform 186 on the detector signal. Thus, as an example of applying the first processing step 184 and / or the fast Fourier transform 186 to the detector signal S px,i 176, a signal S can be generated px 188 (also called "pixel signal S px 188”), the signal may no longer be a function of time. Specifically, the frame signal S px,i The time dependency of 176 can be eliminated by one or more of the steps forming part of the first software component 1, whereas the wavelength dependency may still be present in the start signal S px 188, as indicated by the index "pn". Figure 3 The provision of the signal S to the second software 182 is further illustrated by an arrow. px 188 process. The second software 182 can be configured to px188 performs at least one second processing step 190 (also referred to as “processing 2”), for example by applying at least one algorithm to the signal S px 188, thereby generating at least one corrected signal S px,corr 191. In particular, the second processing step 190 may comprise one or more of the following: correction of the dark signal; correction of dark signal drift; correction of fluctuation effects; correction of the photodetector response of individual detector elements or individual time steps; correction of environmentally induced (e.g. temperature induced) photodetector response variations; extraction of information for subsequent processing; manipulation of at least one parameter, e.g. addition or multiplication with a parameter, the addition or multiplication being generated as a function of information about at least one electrically measurable quantity (e.g. forward voltage) or about the device temperature. In particular, the corrected signal S px,corr 191 may include a plurality of corrected signals, such as a plurality of corrected electronic signals. Each of the plurality of corrected signals may specifically correspond to a corrected count number of a corresponding pixel.

[0253] The spectrometer device 110 comprises at least one evaluation unit 136 for evaluating at least one detector signal generated by the detector 128 and for deriving spectroscopic information about the object 112 from the detector signal. The evaluation unit 136 is configured to take into account an item of information about at least one operating parameter when deriving the spectroscopic information from the detector signal. The evaluation unit 136 can be configured, in particular by software programming, for evaluating and / or processing the detector signal as part of a first processing step 184 of at least one first software 180. The evaluation unit 136 can in particular be configured for determining at least one correction based on the item of information about the at least one operating parameter and can further be configured for correcting the at least one detector signal by using the correction. Thus, the evaluation unit 136 can process and correct the signal S px 188 to generate a signal S px,i,corr , the signal may then be further processed, for example by applying a Fast Fourier Transform 186 .

[0254] For example, as described in more detail above, both the light emitting diode 118 and the luminescent material 120 can be based on different materials and / or different material compositions, which generally affects the spectrum 192 of the phosphor LED 122. However, even when operated at a specific predetermined current, the spectrum 192 or spectral characteristics of a particular phosphor LED 122 may change with temperature. These changes can include a shift in the emission peak 193, a broadening or narrowing of the spectrum 192, an increase or decrease in emission, etc. However, in many cases, the emission at some wavelengths is affected to a greater extent than the emission at other wavelengths. This effect is caused by Figure 4The graph shown shows a superposition of infrared radiation spectra 192 of phosphor LEDs 122 at various temperatures. Specifically, Figure 4 The graph in FIG shows the variation of power spectral density (PDS) 194 in microwatts per nanometer (µW / nm) on the y-axis 196 as a function of wavelength 198 given in nanometers on the x-axis 200. For the spectrum 192 shown, the temperature range at which the phosphor LED 122 generates the illumination light 116 is from 25°C to 50°C. Typically, there is a specific central wavelength within the spectrum 192 where the power spectral density generally does not vary with temperature. Therefore, each wavelength generally has its own temperature coefficient with respect to the increment / decrement of power. Thus, as shown from Figure 4 As is evident in Figure 19, the shape of the spectrum 192 changes with temperature. To visualize this effect more clearly, Figure 4 192. The wavelength intervals are delimited by dashed lines. Specifically, the following four wavelengths and their corresponding intervals are labeled with the following reference numerals: 1643 nm is indicated by reference numeral 202, 1750 nm is indicated by reference numeral 204, 1802 nm is indicated by reference numeral 206, and 1950 nm is indicated by reference numeral 208. For each of these wavelengths, Figure 5 The graph shows the variation of the transmit power normalized to the transmit power variation at 25°C over the temperature range from 25°C to 50°C. Figure 5 In the graph of , the transmit power variation (given in percentage) normalized to the transmit power variation at 25°C is shown on the y-axis 196 and denoted by reference numeral 219 , while the temperature in °C (denoted by reference numeral 220 ) is indicated on the x-axis 200 . Figure 5 The line in the graph in indicates the fitted curve 236. Figure 5 As is apparent from the graph, the emission power at the central wavelength of 1802 nm can have very little variation (i.e., the emission power variation is zero or close to zero) over the observed temperature range, whereas for other wavelengths (e.g., for 1643 nm or 1953 nm), the emission power variation can have significant variation.

[0255] When a specific current (e.g., a current of a specific predefined value) is generated through the light emitting diode 118 by applying a forward voltage to the light emitting diode 118, the appropriate forward voltage may be a function of the temperature of the light emitting diode 118. Therefore, when the same current is applied to the light emitting diode 118, the forward voltage of the LED 118 generally decreases as the temperature increases. Each type of LED 118 has its own forward voltage-temperature characteristic curve. Generally, the forward voltage of the LED 118 decreases linearly as the temperature increases, such as when the temperature of the LED 118 is higher. to Slope in the range of V / K. Figure 6 This relationship is demonstrated for a particular LED 118. In particular, Figure 6 The graph shows the forward voltage applied to the LED 118 for generating a DC current of 150 mA through the LED 118 as a function of the temperature of the LED 118. The forward voltage in volts is indicated by reference numeral 224 on the y-axis 196. The temperature in °C is indicated by reference numeral 220 on the x-axis 200. Figure 6 As is evident from the figure, in this case the forward voltage decreases linearly with increasing temperature. Figure 5 The curve in can be described by the following equation:

[0256]

[0257] in, represents the forward voltage and Indicates temperature. Figure 6 In the figure, a measurement point 221 represented by a gray solid circle and a dashed line corresponding to the above-given fitting curve 236 are shown. Instead of the relationship and / or curve between the forward voltage and the temperature as described above in an exemplary manner, a relationship between another electrically measurable quantity required to drive the light source and the temperature can be used, such as the fed electric power; current; resistance, inductance, capacitance, etc.

[0258] Thus, by using at least one operating parameter as correction parameter, individual temperature corrections can be performed for the spectra 192 at different wavelengths. In particular, the evaluation unit 136 can be configured to individually correct the detector signal S px,i The method of claim 130 is directed to a plurality of detector signals of the optical system 134, and is used to combine the individually corrected detector signals to obtain spectroscopic information. As outlined above, the individual corrections can be performed by using an array of photosensitive elements 134, wherein each photosensitive element can be configured to generate at least one detector signal, and wherein each detector signal can be individually corrected using at least one operating parameter as a correction parameter. Finally, the corrected detector signals can be combined to obtain spectroscopic information.

[0259] In order to obtain spectroscopic information (in particular, a spectrum) about the object 112, the spectrometer device 110 (in particular, the evaluation unit 136) can specifically take into account the properties of the luminescent material 120 used in the light source 114. As outlined in more detail above, the luminescent material 120 can be configured to absorb primary photons generated by the light-emitting diode 118 and, in response, can emit secondary photons either instantaneously or after a delay or decay time. The signal or emission of the phosphor LED 122 after the forward current is turned off can be described using equations (1) and (2) as described above.

[0260] Thus, the characteristic of the luminescent material 120 may in particular be the decay constant 228 and the growth constant , the decay constant can describe the typical time of afterglow of the luminescent material 120, and the growth constant can describe the typical time to reach saturation of emission of the converted light. and The decay constant is typically different between different phosphor LEDs 122 and / or between different types of luminescent materials 120. and the growth constant Can depend on wavelength. The time constant is usually extracted from the step response of the optical signal by applying / cutting off the forward current. Figure 7A and Figure 7B Spectra 192 of two different types of phosphor LEDs 122 that emit light in the near infrared range are shown. Specifically, the power spectral density is shown as a function of wavelength, which is given in nm. Figure 7A and Figure 7B As is apparent from FIG, the spectra 192 of the two different phosphor LEDs 122 are different. Thus, as an example, Figure 7A The spectrum 192 shown in FIG reflects high emission in the range from 1400 nm to 1600 nm, whereas emission in this region is negligible for the phosphor LED 122, which has a spectrum 192 in the range of 1400 nm to 1600 nm. Figure 7B The phosphor LED 122 (whose spectrum is Figure 7A The decay constant is shown in and the growth constant respectively Figure 8A and Figure 8B The phosphor LED 122 (whose spectrum is given in Figure 7B The decay constant is shown in and the growth constant respectively Figure 9A and Figure 9Bis given as a function of wavelength. Specifically, Figure 8A and Figure 9A The corresponding decay constant in ms is shown on the y-axis 196 (indicated by reference numeral 228 ) versus wavelength 198 in nm on the x-axis 200 ; and Figure 8B and Figure 9B The corresponding growth constant in ms is shown on the y-axis 196 (indicated by reference numeral 230) versus wavelength 198 in nm on the x-axis 200. Data points from different replicates are marked with different shades of grey.

[0261] Another characteristic of LEDs 118 is that their light output power varies with forward current. Thus, generally, by increasing the forward current (specifically, the input current), the power emitted by LED 118 increases. The shape (e.g., slope) of the light output versus forward current curve is characteristic of each LED 118. Figure 10 An example of such a curve is shown in FIG. Figure 10 In the graph of FIG. 2 , normalized light output 232 of a phosphor LED is shown as a function of forward current 234 , which is given in amperes.

[0262] exist Figure 11 In FIG. 2 , a method 236 of operating a spectrometer device 110 for obtaining spectroscopic information about at least one object 112 is presented. The method 236 comprises the following method steps:

[0263] i. Step 238 of illuminating the object with illumination light 116 generated by at least one light source 114 of the spectrometer device 110, the light source 114 comprising at least one light-emitting diode 118 and at least one luminescent material 120 for photoconverting the primary light generated by the light-emitting diode 118;

[0264] ii. a step 240 of determining at least one actual value of at least one operating parameter of the spectrometer device 110 by using at least one drive unit 138 of the spectrometer device 110 , the drive unit 138 being configured for electrically driving the light source 114 ;

[0265] iii. Step 242 of detecting the detection light from the object 112 by using the at least one detector 128 of the spectrometer device 110 and generating at least one detector 128 signal; and

[0266] iv. a step 244 of evaluating the detector signal by using at least one evaluation unit 136 of the spectrometer device 110 to derive spectroscopic information about the object 112 therefrom, the evaluation unit 136 being configured for selecting at least one correction information item from a predetermined set of correction information items depending on the actual value of at least one operating parameter and for taking into account the selected correction information item to derive the spectroscopic information.

[0267] The set of correction information items may be specific to an individual spectrometer device 110 and / or specific to a plurality of spectrometer devices 110 , in particular wherein the set of correction information items is assigned to each spectrometer device 110 according to its serial number.

[0268] The detector 128 may provide at least one raw detector 128 signal in step iii., wherein, in step iv., the evaluation unit 136 may correct the raw detector 128 signal into at least one corrected detector 128 signal by using at least one selected correction information item. The evaluation unit 136 may include a database having a plurality of correction information items stored therein as a function of the value of at least one different operating parameter. The database may include at least one lookup table, which is specifically configured to provide the plurality of correction information items that the evaluation unit 136 considers for deriving the spectroscopic information.

[0269] The at least one operating parameter comprises a set of at least two operating parameters. The at least two operating parameters can be independently selected from the group consisting of: an input current applied to the light-emitting diode 118; a voltage applied to the light-emitting diode 118; an electrical power applied to the light-emitting diode; a forward voltage of the light-emitting diode 118; a forward current of the light-emitting diode 118; an ambient temperature; a temperature within the spectrometer device 110, in particular a temperature within at least one of the following: the light source 114, the drive unit 138, the detector 128, or the evaluation unit 136; operating protocol parameters, in particular the number and / or sequence of measurements, the measurement duration, a duty cycle, parameters related to the operating protocol of the light source 114, and parameters related to the operating parameters of the detector 128.

[0270] The at least two operating parameters include at least one temperature (specifically, at least one of an ambient temperature and a temperature within spectrometer device 110), and at least one of an electrical operating parameter of spectrometer device 110 and an optical operating parameter of spectrometer device 110. The at least two operating parameters may further include at least one operating scenario parameter. The method may be at least partially computer-implemented, particularly step iv.

[0271] exist Figure 12In FIG. 2 , a calibration method 246 for compiling a set of correction information items for use in the method 236 for operating the spectrometer device 110 is presented. The calibration method 246 comprises the following method steps:

[0272] I. step 248 of performing a plurality of calibration measurements under different operating conditions of the spectrometer device 110 , each calibration measurement comprising measuring a system response of the spectrometer device 110 in a controlled environment, the system response comprising spectral information;

[0273] II. Step 250 of recording at least one value of at least one operating parameter for each of these calibration measurements;

[0274] III. Step 252 of compiling a set of correction information by comparing the spectral information with at least one recorded value of at least one operating parameter for each of these calibration measurements.

[0275] Method 246 may include performing calibration measurements under predetermined and controlled environmental conditions. Step III. may include storing at least one of the emission spectrum, a correction function for the emission spectrum, or a correction factor for the emission spectrum in a lookup table. The calibration measurements may be performed at different ambient temperatures.

[0276] As shown in the exemplary calibration setup 266 Figure 13 As further illustrated in FIG, step I. may include using an external detector 254, specifically at least one of an external spectrometer 268 and an external power meter 270. The calibration method may include using an external power meter 270 having at least one wavelength selective element, specifically at least one of an optical filter, a dispersive element, and a diffractive element.

[0277] Step I. can include using light source 114 of spectrometer device 110 and using at least one calibration target 260, specifically at least one diffuse reflectance calibration target 260 having known reflectance spectral characteristics, wherein step I. can further include performing a plurality of spectral measurements with a predetermined repetition rate, specifically at least 0.1 Hz, 0.5 Hz, 1 Hz, 2 Hz, 5 Hz, or 10 Hz, using light emitting diodes 118 of light source 114. The at least one diffuse reflectance calibration target 260 for determining at least one performance parameter associated with detector 128 can be comprised by an integrating sphere 272, wherein integrating sphere 272 is configured for connecting spectrometer device 110 to an external detector and / or an external light source, for example, by using at least one optical port.

[0278] Step II. may comprise recording at least two, in particular at least three, and more in particular all operating parameters from a list of operating parameters consisting of: an input current applied to the light-emitting diode 118, a voltage applied to the light-emitting diode 118, a forward voltage of the light-emitting diode 118 and a forward current of the light-emitting diode 118, operating scheme parameters (in particular as the number and / or sequence of measurements), a measurement duration, parameters related to the operating scheme of the light source 114, parameters related to the operating parameters of the detector 128; and wherein the calibration method may further comprise recording at least one optical signal, wherein the at least one optical signal comprises at least one of a detector 128 signal of the detector 128 of the spectrometer device 110 and a signal provided by an external detector 254, in particular an external power meter, and wherein step III. may comprise deriving correction information by taking into account the optical signal.

[0279] A further correction information item for correcting at least one determined actual value of at least one operating parameter determined by the drive unit 138 may be determined by using the external measurement arrangement 262, and wherein step III. may comprise taking the further correction information item into account when compiling the set of correction information. Figure 13 As further shown in FIG. 1 , the external measurement setup 262 can be electronically coupled to the spectrometer device 110 using an electronic coupling 264 .

[0280] The light source 114 may be driven in a predefined scheme in such a way that the temperature of the light source 114 may be set to a predefined value, in particular by taking into account the further item of correction information and / or the thermal mass of the light source 114 .

[0281] Performing multiple calibration measurements under different operating conditions of spectrometer device 110 in step I. can be performed by determining at least one performance parameter by at least one of the following: using an external light source 256, in particular an external light source with a known emission spectrum, to determine at least one performance parameter related to detector 128; or using an external detector 254, in particular an external detector with a known spectral efficiency, to determine at least one performance parameter related to detector 128; wherein the at least one performance parameter is taken into account in compiling a set of calibration information in step III. Thus, in particular, external light source 256 and / or external detector 254 can be optically connected to spectrometer device 110, for example, using at least one optical fiber and / or a plurality of optical fibers (e.g., comprised of a bundle of optical fibers). Optical coupling 258 can be provided via a diffusely reflective calibration target 260, in particular, comprised of an integrating sphere 272. The optical connection can be configured to propagate light in a first direction and / or a second direction opposite to the first direction. In particular, thereby, light generated by the spectrometer device 110 may propagate from the diffusely reflective target to at least one of: the spectrometer device 110 , the external light source 256 , or the external detector 254 .

[0282] Determination of the performance parameters of the light source 114 may be performed after determination of the performance parameters of the detector 128 , in particular to ensure that the detector 128 is not affected by heat generated by the light source 114 .

[0283] The calibration method may be repeated for another light source 114 of the same type, wherein another set of correction information specific to the other light source 114 may be compiled.

[0284] List of Reference Numerals

[0285] 110 spectrometer equipment

[0286] 112 objects

[0287] 114 light source

[0288] 116 illumination light

[0289] 118 LEDs

[0290] 120 luminous materials

[0291] 121 Semiconductor Materials

[0292] 122 phosphor light-emitting diodes

[0293] 124LED die

[0294] 126 shell

[0295] 128 detectors

[0296] 130 detection light

[0297] 132 optical detectors

[0298] 134 photosensitive element array

[0299] 136 evaluation units

[0300] 138 drive unit

[0301] 139 measurement units

[0302] 140 current source

[0303] 142 Voltage measuring equipment

[0304] 144 Data processing equipment

[0305] 146 Pretreatment Equipment

[0306] 148 data storage devices

[0307] 150 filter elements

[0308] 151 Optical components

[0309] 152 wavelength selection element

[0310] 154 substrate

[0311] 156 ceramic substrate

[0312] 158 contact pads

[0313] 160 Converter

[0314] 162 side coating

[0315] 164 hardware components

[0316] 166 software components

[0317] 168LED temperature

[0318] 170 Temperature of luminescent material

[0319] 172 Detector temperature

[0320] 174 target signal S t

[0321] 176 Electronic detector signal S px,i

[0322] 178 Readout Electronics

[0323] 180 Software 1

[0324] 182 Software 2

[0325] 184 First processing step

[0326] 186 Fast Fourier Transform

[0327] 188 pixel signal S px

[0328] 190 Second processing step

[0329] 191 Signal S px,corr

[0330] 192 Spectrum

[0331] 193 peak

[0332] 194 Power spectral density, unit: microwatt per nanometer

[0333] 196y-axis

[0334] 198 wavelength, unit: nm

[0335] 200x axis

[0336] 2021643 nm

[0337] 2041750 nm

[0338] 2061802 nm

[0339] 2081950 nm

[0340] 219 Transmitted power variation normalized to 25°C (given in percent)

[0341] 220 Temperature, unit: °C

[0342] 221 measuring points

[0343] 224 Forward voltage, unit: volt

[0344] 226 signals, expressed as counts

[0345] 228 decay constant , unit: ms

[0346] 230 Growth Constant , unit: ms

[0347] 232 Normalized Light Output

[0348] 234 Forward current, unit: ampere

[0349] 236 Method of operating a spectrometer device

[0350] 238 Method step i.: Irradiating the object

[0351] 240 Method step ii.: Determine the value of the operating parameter

[0352] 242 Method step iii.: Detecting detection light from the object

[0353] 244 Method step iv.: Evaluating the detector signal

[0354] 246 Calibration method for compiling a set of correction information items

[0355] 248 Method step I: Perform multiple calibration measurements

[0356] 250 Method step II.: Record the values ​​of operating parameters

[0357] 252 Method Step III: Compiling a Set of Calibration Information

[0358] 254 external detectors

[0359] 256 external light sources

[0360] 258 Optical coupling; optical fiber

[0361] 260 calibration targets

[0362] 262 External measurement setup

[0363] 264 electronic coupling

[0364] 266 calibration settings

[0365] 268 External Spectrometer

[0366] 270 external power meter

[0367] 272 scoring balls

Claims

1. A method (236) of operating a spectrometer device for obtaining spectroscopic information about at least one object (112), the method comprising: i. illuminating the object (238) with illumination light (116) generated by at least one light source (114) of the spectrometer device (110), the light source (114) comprising at least one light-emitting diode (118) and at least one luminescent material (120) for photoconverting primary light generated by the light-emitting diode (118); ii. determining at least one actual value (240) of at least one operating parameter of the spectrometer device (110) by using at least one drive unit of the spectrometer device (110), the drive unit being configured to electrically drive the light source (114); iii. detecting the detection light (242) from the object (112) by using at least one detector (128) of the spectrometer device (110) and generating at least one detector (128) signal; as well as iv. evaluating the detector signal (244) by using at least one evaluation unit (136) of the spectrometer device (110) to obtain the spectroscopic information about the object (112) therefrom, the evaluation unit (136) being configured for selecting at least one correction information item from a predetermined set of correction information items depending on the actual value of the at least one operating parameter, and for taking into account the selected correction information item to obtain the spectroscopic information, wherein the at least one operating parameter comprises a set of at least two operating parameters, wherein the at least two operating parameters comprise at least one temperature and at least one of an electrical operating parameter of the spectrometer device (110) and an optical operating parameter of the spectrometer device (110).

2. The method according to the preceding claim, the evaluation unit (136) comprising a database having stored therein a plurality of correction information items as a function of the value of the at least one different operating parameter.

3. The method according to the preceding claim, wherein The database includes at least one lookup table.

4. A method according to any one of the preceding claims, wherein The at least two operating parameters further include at least one operating protocol parameter.

5. A calibration method (246) for compiling a set of correction information items for use in a method according to any one of the preceding claims, the calibration method comprising: I. performing a plurality of calibration measurements (248) under different operating conditions of the spectrometer device (110), each calibration measurement comprising measuring a system response of the spectrometer device (110) in a controlled environment, the system response comprising spectral information; II. recording at least one value of the at least one operating parameter for each of the calibration measurements (250); III. Compiling a set of correction information (252) by comparing the spectral information with at least one recorded value of the at least one operating parameter for each of the calibration measurements, wherein the at least one operating parameter comprises a set of at least two operating parameters, wherein the at least two operating parameters comprise at least one temperature and at least one of an electrical operating parameter of the spectrometer device (110) and an optical operating parameter of the spectrometer device (110).

6. The calibration method (246) according to any of the preceding claims relating to calibration methods, wherein Step I. includes using a light source (114) of the spectrometer device (110) and using at least one calibration target, wherein step I. further includes performing a plurality of spectral measurements at a predetermined repetition rate using a light emitting diode (118) of the light source (114).

7. The calibration method (246) according to any of the preceding claims relating to calibration methods, wherein Step II. comprises recording at least two of the following: an input current applied to the light-emitting diode (118), a voltage applied to the light-emitting diode (118), a forward voltage of the light-emitting diode (118) and a forward current of the light-emitting diode (118), operating scheme parameters, measurement duration, parameters related to the operating scheme of the light source (114), parameters related to the operating parameters of the detector (128); and wherein the calibration method further comprises recording at least one light signal, wherein the at least one light signal comprises at least one of a detector (128) signal of the detector (128) of the spectrometer device (110) and a signal provided by an external detector (254), and wherein step III. comprises deriving the correction information by taking the light signal into account.

8. The calibration method (246) according to any of the preceding claims relating to calibration methods, wherein A further correction information item for correcting at least one determined actual value of at least one operating parameter determined by the drive unit is determined by using an external measurement arrangement (262), and wherein step III. comprises taking the further correction information item into account when compiling the set of correction information.

9. The calibration method (246) according to any of the preceding claims relating to calibration methods, wherein The light source (114) is driven in a predefined scheme in such a way that the temperature of the light source (114) is set to a predefined value.

10. The calibration method (246) according to any of the preceding claims relating to calibration methods, wherein Performing a plurality of calibration measurements at different operating conditions of the spectrometer device (110) in step I. is performed by determining at least one performance parameter by at least one of the following operations: using an external light source (256) to determine the at least one performance parameter associated with the detector (128); or determining the at least one performance parameter associated with the detector (128) using an external detector (254); Therein, in step III. a set of correction information is compiled taking into account the at least one performance parameter.

11. A spectrometer device (110) for obtaining spectroscopic information about at least one object (112), the spectrometer device (110) comprising: A. at least one light source (114) for generating illumination light (116) for illuminating the object (112), the light source (114) comprising at least one light-emitting diode (118) and at least one luminescent material (120) for light-converting primary light generated by the light-emitting diode (118); B. at least one driving unit for driving the light source (114), the driving unit being configured to determine at least one actual value of at least one operating parameter of the spectrometer device (110); C. at least one detector (128) for detecting light from the object (112) and for generating at least one detector (128) signal; as well as D. At least one evaluation unit (136) for evaluating the detector (128) signal and for deriving the spectroscopic information about the object (112) therefrom, the evaluation unit (136) being configured for selecting at least one correction information item from a predetermined set of correction information items based on the actual value of the at least one operating parameter, and for taking into account the selected correction information item to derive the spectroscopic information, wherein the at least one operating parameter comprises a set of at least two operating parameters, wherein the at least two operating parameters comprise at least one temperature and at least one of an electrical operating parameter of the spectrometer device (110) and an optical operating parameter of the spectrometer device (110).

12. A computer program comprising instructions which, when executed by a spectrometer device (110) according to any of the preceding claims relating to a spectrometer device (110), cause the spectrometer device (110) to perform a method of operating a spectrometer device (110) according to any of the preceding claims relating to a method of operating a spectrometer device (110).

13. A computer-readable storage medium comprising instructions which, when executed by a spectrometer device (110) according to any one of the preceding claims relating to a spectrometer device (110), cause the spectrometer device (110) to perform a method of operating a spectrometer device (110) according to any one of the preceding claims relating to a method of operating a spectrometer device (110).

14. A non-transitory computer-readable medium comprising instructions which, when executed by one or more processors of an evaluation unit (136) of a spectrometer device (110) according to any of the preceding claims relating to a spectrometer device (110), cause the one or more processors to perform a method of operating a spectrometer device (110) according to any of the preceding claims relating to a method of operating a spectrometer device (110).

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