Stable modulated two-channel broadband light source

Abstract

A spectral light source (112) is proposed. The spectral light source (112) comprises: - at least one light emitting element (128); - at least one electronic circuit (136) configured to apply electrical power to said light emitting elements (128); - at least one housing (150), said housing (150) at least partially surrounding said light emitting element (128); - at least two output channels (156) extending through said housing (150), each of said output channels (156) configured to separate at least one light beam (116) from a spectral light source (112); Equipped with. The spectral light source (112) is configured to independently control each of the output channels (156).

Description

[Technical field]

[0001] The present invention generally relates to a spectroscopic light source, a spectroscopic measurement system, and a method of operating a spectroscopic measurement system. As an example, the device and method of the present invention can be employed in the field of spectroscopy. This may specifically include spectrometers operating in the visible light spectrum or the infrared spectrum, more specifically in the near infrared spectrum or the mid-infrared spectrum. It may further include Fourier transform infrared (FTIR) devices or gas spectroscopy. Furthermore, the device and method of the present invention can also be employed in interferometric applications, such as white light interferometers. Thus, the device and method of the present invention can be used in particular for laboratory measurements. Nevertheless, it can also be used in industrial environments, including at-line and in-line measurements. The device and method of the present invention can also be used in consumer environments, for example for measuring air quality. However, other applications are possible. [Background technology]

[0002] A large number of spectroscopic light sources for spectroscopic measurements are known from the prior art. Such spectroscopic measurements often require two or more separate light beams, for example one measurement light beam and one reference light beam. Therefore, additional optical elements, in particular beam splitters, are usually applied to generate these two or more light beams in the spectroscopic light source. A rather time-consuming method is to perform at least two successive measurements, one of which serves as the reference. Many spectroscopic measurements further require that the two or more light beams have different optical properties, for example different modulation depths. This can in particular be related to periodic modulations with different modulation frequencies, which can be realized for example by using chopper wheels or tuning forks. All this increases the complexity of the structure and makes the spectroscopic measurement system more susceptible to errors. In particular, defects, dust, scratches, etc. in the optical elements inevitably cause light scattering. Such stray light also affects the accuracy of the spectroscopic measurements. Another drawback of the successive measurements is caused by short-term fluctuations of the light path, the light source or the light bulb. These fluctuations can usually lead to systematic differences between the reference and the sample measurements. This leads to additive noise.

[0003] EP0729017A1 discloses a method for correcting the effects of stray light in measurements and spectrometers, and the use of the method for improving the linearity and accuracy of the spectrometer. Light from a broadband light source is blocked in a specific wavelength band by an optical filter, and light outside the specific wavelength band is transmitted by the filter. The spectroscopic measurement in the specific band measures an aggregate offset, including the effects of stray light, dark current, and electronic offset. In an absorption spectrometry method, a first spectroscopic measurement in the specific band is measured in the absence of a chemical sample, and a second measurement is performed in the presence of a chemical sample. The first spectroscopic measurement is used to correct a reference spectrum, and the second spectroscopic measurement is used to correct a sample spectrum, each in the specific band. In addition, corrections are made for the insertion loss of the filter and for stray light having wavelengths within the specific wavelength band. However, the method disclosed in EP0729017A1 requires additional process steps, which are performed consecutively. Therefore, the method disclosed in EP0729017A1 requires additional time before the actual spectroscopic measurement can begin.

[0004] In addition, typical spectroscopic light sources require a long heat-up time, which means that the spectroscopic light source emits light in an unstable state for a long time after it is switched on. However, this state is not suitable for reliable and precise spectroscopic measurements. Therefore, before performing spectroscopic measurements, you must wait for the heat-up time to elapse until the spectroscopic light source is stable. For this reason, spectroscopic light sources are often not switched off and are turned on for longer than actually required. This also results in a shortened spectroscopic light source's lifespan.

[0005] JP 05-144576 A discloses a device for gradually increasing the brightness of an incandescent lamp when a switch is turned on. A terminal is provided to which a series circuit of an AC power source AC and an incandescent lamp L is connected. A soft start circuit is provided inside the terminal. When the switch SW1 is turned on, the transistor Q4 is turned off, the charge of the capacitor C6 starts to discharge, and the potential at point (c) starts to drop. Therefore, the collector current of the transistor Q3 decreases and the impedance at point (d) increases. When Ve>Vf+VQ1BE, the transistor Q1 turns on, the triac Q5 turns on, and the incandescent lamp L lights up. The above operation is repeated every half cycle until the charge of the capacitor C6 is completely discharged. However, since the impedance at point (d) gradually increases, the phase at which the triac Q5 turns on becomes faster accordingly. When the charge of the capacitor C6 is completely discharged, the impedance at point (d) becomes constant, and the trigger phase of the triac Q5 becomes constant.

[0006] JP3300173B2 discloses an overload detector and an incandescent lamp controller capable of detecting an overcurrent by canceling the fluctuation of the input power supply voltage through the detection of the overcurrent via a DC circuit. The instantaneous value of the commercial power supply voltage is detected by an instantaneous value detection circuit, and the load current is converted to a voltage by a current transformer and then led to an overcurrent detector. When the instantaneous value reaches a predetermined voltage, the overcurrent detector detects an overcurrent based on whether the output voltage of the current transformer is equal to or higher than a threshold value, and outputs the result to a phase control circuit. When an overcurrent is detected, the phase control circuit outputs a gate control signal to a triac so that the incandescent lamp lights up at a half wavelength.

[0007] WO2005 / 050148A2 discloses a system and method for providing spectroscopic measurements. In one embodiment, a spectroscopic measurement device comprises at least one radiation source configured to provide N (N≧2) linearly independent illumination sources characterized by M (M≧N) wavelength channels in a predetermined wavelength range; a sensor unit including at least one sensor configured for optical communication with the radiation source and the object; a memory storing an illumination light characteristic matrix including the spectral characteristics of the N illumination sources in the M wavelength channels; and a processor configured to provide a spectral response of the object in the M wavelength channels based at least in part on the illumination light characteristic matrix. The embodiments of the described document can be used to build a new class of miniature spectroscopic measurement devices, such as portable color measurement devices.

[0008] US3277773A discloses a radiation measuring device, more specifically a device for measuring radiant energy reflected from a sample.

[0009] WO2017 / 040431A1 discloses a system and method for measuring the concentration and type of a substance in a sample at a sampling interface. The system includes a light source, one or more optics, one or more modulators, a reference, a detector, and a controller. The disclosed system and method can account for drifts originating from the light source, the one or more optics, and the detector by sharing one or more components between different measurement paths. Furthermore, the system can distinguish between different types of drifts and eliminate erroneous measurements due to stray light by placing one or more modulators between the light source and the sample or reference. Furthermore, the system can detect substances along various positions and depths in the sample by mapping the detector pixels and micro-optics to positions and depths in the sample.

[0010] WO2011 / 072870A1 discloses a ring light, in particular for optical spectrometers. With conventional ring lamps, it is possible to use the irradiated light as a reference for measurements, but this is at great expense and, moreover, has limited accuracy. The described application aims to make it possible to obtain reference radiation with less effort. For this purpose, in at least one inlet bundle of the ring lamp, the inlet ends of several reference light guides are additionally arranged, the outlet ends of which are combined away from the ring to form at least one reference bundle.

[0011] US2009 / 316149A1 discloses, in one embodiment, a spectrophotometer with a modular 45 / 0 head. One embodiment of an apparatus for measuring the reflectance of a sample includes a plurality of light emitting diodes for emitting light, a reflective housing (the reflective housing is a dome having a plurality of openings formed around its periphery) disposed above the plurality of light emitting diodes, a sample channel for capturing a first portion of the light (the first portion of the light interacts with the sample), and a reference channel for capturing a second portion of the light (the second portion of the light is independent of the sample).

[0012] Despite the advantages achieved by known spectroscopic light sources, various technical challenges remain. Thus, additional optical elements are generally required to provide two or more light beams. This makes the spectroscopic measurement system more complex and susceptible to errors. Alternatively, at least two successive measurements can be performed. However, this approach requires more time and may make the spectroscopic measurement system more susceptible to short-term fluctuations. Summary of the Invention [Problem to be solved by the invention]

[0013] It is therefore desirable to provide a spectroscopic light source, a spectroscopic measurement system and a method of operating a spectroscopic measurement system that are suitable for spectroscopic measurements and that at least partially address the above-mentioned problems of known devices and methods of a similar type. In particular, it is desirable to provide a device and a method that are suitable for generating two or more separate and potentially different light beams for spectroscopic measurements, while in particular avoiding the problem of a significant increase in either the measurement time or the complexity of the structure of the spectroscopic light source (which also relates to an increased susceptibility of the spectroscopic measurements to errors and added noise). It is particularly desirable that the light beam further exhibits high short-term and / or long-term stability, and that the spectroscopic light source is switchable without affecting the stability of the light beam. [Means for solving the problem]

[0014] This problem is solved by a spectroscopic light source, a spectroscopic measurement system and a method for operating a spectroscopic measurement system with the features of the independent patent claims. Advantageous embodiments, which can be realized individually or in any combination, are set out in the dependent claims as well as in the full specification.

[0015] As used herein, the terms "having", "comprises" or "including" as well as any grammatical variations thereof are used in a non-exclusive manner. Thus, these terms can refer both to the situation where, apart from the features introduced by these terms, no further features are present in the entity described in this context, and to the situation where one or more further features are present. As an example, the terms "A has B", "A comprises B" and "A includes B" can refer both to the situation where no other elements are present in A apart from B (i.e., A consists solely and exclusively of B), and to the situation where, apart from B, one or more further elements are present in the entity A, such as element C, elements C and D, or even another element.

[0016] Furthermore, it should be noted that the terms "at least one," "one or more," or similar language indicating that a feature or element may be present one or more times will typically be used only once when introducing each feature or element. In most cases, when referring to each feature or element, the language "at least one" or "one or more" will not be repeated regardless of the fact that each feature or element may be present one or more times.

[0017] Furthermore, as used below, the terms "preferably", "more preferably", "particularly", "more particularly", "particularly", "more particularly" or similar terms may be used with any feature without limiting alternative possibilities. Thus, features introduced by these terms are optional features and are not intended to limit the scope of the claims in any way. As a person skilled in the art will recognize, the invention may be implemented by using alternative features. Similarly, features introduced by "in an embodiment of the invention" or similar expressions do not impose any limitations with respect to alternative embodiments of the invention, do not impose any limitations with respect to the scope of the invention, and do not impose any limitations with respect to the possibility of combining the features so introduced with other optional or non-optional features of the invention.

[0018] In a first aspect of the present invention, a spectral light source is proposed. The term "spectroscopy" as used herein is a broad term and should be given its ordinary and customary meaning to those skilled in the art and should not be limited to a special or customized meaning. The term may specifically refer to, but is not limited to, the process of studying or analyzing the interaction of matter with electromagnetic radiation as a function of the wavelength or frequency of the radiation. The adjective "spectroscopic" may therefore refer to the purpose of being usable for spectroscopy. The term "spectroscopic" may therefore specifically be synonymous with the terms "for use in spectroscopic applications" and / or "usable for spectroscopic applications". Spectroscopy may specifically refer to the study of color generalized from visible light to all bands of the electromagnetic spectrum. Spectroscopy may specifically be a process that involves splitting light according to at least one optical property of light, such as wavelength, frequency, wave number, or energy. Thus, by way of example, spectrometry may refer to optical measurements, in which a measurement variable, such as the absorption of light by a measured object, is measured in dependence on the split optical property of light, such as the wavelength of light.

[0019] The term "light" as used herein is a broad term and should be given its ordinary and customary meaning to those skilled in the art and should not be limited to any special or customized meaning. The term may specifically refer to, but is not limited to, electromagnetic radiation in the wavelength range of 10 nm to 1 mm. Specifically, the spectral light source may be configured to emit light of at least one wavelength or at least one spectral range in the visible and / or infrared spectral range, specifically the near-infrared spectral range. Therein, the spectral range of 380 nm to 760 nm may be referred to as the visible spectral range, the wavelength range of light having a shorter wavelength than the visible spectral range may be referred to as the ultraviolet spectral range, and the wavelength range of light having a longer wavelength than the visible spectral range may be referred to as the infrared spectral range. Therein, the spectral range of 760 nm to 1.4 μm may be referred to as the near-infrared (NIR) spectral range. The spectral range of 1.4 μm to 3 μm may also be referred to as the long-wavelength near-infrared spectral range or the short-wavelength mid-infrared spectral range.

[0020] Thus, the term "spectral light source" as used herein is a broad term and should be given its ordinary and customary meaning to those skilled in the art and should not be limited to a special or customized meaning. The term may specifically refer to any device configured to emit light, such as light having predefined and / or controlled optical characteristics for spectroscopic measurements, without limitation. The spectral light source may specifically be configured to emit light having stable optical characteristics. As an example, the spectral light source may generate light over at least one wavelength range, and specifically, over a longer period of time, the light intensity is maintained at at least one predefined value for each wavelength in the wavelength range.

[0021] The spectral light source comprises at least one light-emitting element. The term "light-emitting element" as used herein is a broad term and should be given its ordinary and customary meaning to those skilled in the art and should not be limited to a special or customized meaning. The term may specifically refer to an element configured to emit light, without being limited thereto. In particular, the light-emitting element may be configured to emit light isotropically, i.e. uniformly in all spatial directions. As an example, the light-emitting element may be configured to emit light by thermal heating and / or may be or include at least one thermal emitter. Such thermal heating may specifically be induced by applying electrical power to the light-emitting element, for example to heat an electrical resistor. Thus, the light-emitting element may comprise at least one electrical connection and / or at least one filament. Additionally or alternatively, the light-emitting element may comprise at least one of a light-emitting diode and a laser diode. Further types of light-emitting elements are also possible.

[0022] The spectroscopic light source comprises at least one electronic circuit. The electronic circuit is configured to apply power, specifically a voltage, to the light-emitting element. The term "electronic circuit" as used herein is a broad term and should be given its ordinary and customary meaning to those skilled in the art and should not be limited to a special or customized meaning. The term may specifically refer to an assembly of at least two electronic components, such as, but not limited to, electronic components independently selected from the group consisting of a power source, a resistor, an inductor, a capacitor, a diode, an operational amplifier, or a transistor, which are at least partially interconnected via one or more conductive elements, such as wires and / or traces. The electronic circuit can be configured to generate at least one electrical output, e.g., a voltage, in a controlled manner. As an example, the electronic circuit may be configured to systematically vary the voltage applied to the light-emitting element over time. Thus, as an example, the electronic circuit can comprise at least one controllable power source, current source, or voltage source.

[0023] The spectroscopic light source comprises at least one housing. The housing at least partially surrounds the light-emitting element. The term "housing" as used herein is a broad term and should be given its ordinary and customary meaning to those skilled in the art and should not be limited to a special or customized meaning. The term may specifically refer to, but is not limited to, a mechanical cover configured to at least partially shield the elements inside. The housing may specifically be configured to at least partially shield the elements inside it from external influences of a mechanical nature, for example from collisions with further objects and / or from vibrations. The housing may comprise at least one wall, specifically at least one solid and non-deformable wall. The housing may comprise at least one vibration damping. The housing may further specifically be configured to at least partially shield electromagnetic radiation, specifically thermal radiation. The housing may at least partially shield the light emitted by the light-emitting element, and the light may be at least partially prevented by the housing from leaving the spectroscopic light source. As an example, the housing at least partially surrounding the light-emitting element may comprise at least one wall, which may be configured to prevent further objects from contacting and potentially damaging the light-emitting element, and which may further be configured to prevent light emitted by the light-emitting element from exiting the spectral light source in at least one spatial direction. The wall may comprise at least an opening through which light may pass.

[0024] The spectral light source comprises at least two output channels passing through the housing. Each one of the output channels is configured to separate at least one light beam from the spectral light source. The term "output channel" as used herein is a broad term and should be given its ordinary and customary meaning to those skilled in the art and should not be limited to a special or customized meaning. The term may specifically refer to, without limitation, any element or device configured to transmit light and optionally modifying the light during transmission. As an example, in the spectral light source, the light emitted by the light emitting element is blocked by the housing and thus can only exit the spectral light source through at least one of the output channels. The output channel may comprise at least one opening, specifically at least one opening provided in the housing of the spectral light source. The output channel may include at least one material that is at least partially transparent to the light emitted by the light emitting element of the spectral light source. The output channel may specifically comprise at least one element, more specifically at least one optical element, configured to modify the light emitted by the light emitting element of the spectral light source, which will be described in more detail below.

[0025] The term "decoupling" as used herein is a broad term and should be given its ordinary and customary meaning to those skilled in the art and should not be limited to any special or customized meaning. The term specifically refers to, without limitation, the act of releasing at least one first entity from at least one second entity, where the first entity and the second entity may be independent of each other after the release. As an example, at least one light beam may be emitted by the spectral light source through at least one of the output channels and thus exit the spectral light source through at least one of the output channels. The separated light beam and the spectral light source may then be independent of each other, meaning that the spectral light source is no longer able to manipulate the light beam. The term "light beam" as used herein is a broad term and should be given its ordinary and customary meaning to those skilled in the art and should not be limited to any special or customized meaning. The term specifically refers to, without limitation, an amount of light, specifically light that is emitted anisotropically in at least one direction, such as a directional projection of light. The light beam may in particular travel anisotropically in one particular direction over at least one spatial distance. The light beam may be scattered, in particular reflected, which changes at least a portion of the direction of the light beam or the light intensity of the light beam. The light beam may be split into two or more auxiliary light beams, each traveling in a different direction. The light beam may have a specified or determinable width, which may increase and / or decrease, for example, as a function of the longitudinal position along the optical axis of the light beam.

[0026] The spectral light source is configured to independently control each one of the output channels. The term "independently control" as used herein is a broad term and should be given its ordinary and customary meaning to those skilled in the art and should not be limited to a special or customized meaning. The term may specifically refer to, but is not limited to, the act of regulating a first entity while selectively regulating a second entity equally or differently in parallel or in a time-shifted manner. As an example, a first element may be brought into a first output channel of the spectral light source while no element and / or a second element may be brought into a second output channel, and the first and second elements may be different. The first and second elements may both be the same type of element but have different specific characteristics, for example lenses with different focal points or modulation elements with different modulation frequencies. The first and second elements may belong to different types of elements. For example, the first element may be an aperture and the second element may be an optical filter. Further examples are outlined below. Thus, a first light beam separated via a first output channel may be manipulated differently than a second light beam separated via a second output channel.

[0027] The light-emitting element may comprise at least one incandescent lamp, specifically at least one halogen-filled incandescent light bulb. The term "incandescent lamp" as used herein is a broad term and should be given its ordinary and customary meaning to those skilled in the art and should not be limited to a special or customized meaning. The term may specifically refer to a light-emitting element including at least one heated filament configured to emit light, without being limited thereto. The incandescent lamp may comprise at least one bulb having at least one filament disposed therein. The filament may comprise at least one wire, specifically at least one coiled wire. The filament may comprise tungsten. The bulb may be a glass bulb filled with an inert gas. The inert gas may specifically comprise argon and / or nitrogen. Furthermore, the glass bulb may be filled with a halogen. The halogen may specifically comprise iodine and / or bromine. When power is applied to the light-emitting element, a current flows through the filament, the temperature of the filament increases, and the filament emits thermal radiation. The incandescent lamp may in particular be configured to emit light in the infrared region of the spectrum.

[0028] The housing may at least partially surround the electronic circuit. The housing may therefore at least partially protect the electronic circuit from external influences, such as dust, dirt or water. In particular, sensitive components of the electronic circuit may be arranged inside the housing and robust components of the electronic circuit may be arranged outside the housing. The housing may further be configured to stabilize the temperature of the spectral light source, in particular the light-emitting element. The housing may therefore be configured to dissipate heat from the light-emitting element, which may in particular comprise a heat sink as indicated above.

[0029] The spectral light source can be configured to turn on and off at least one of the output channels. Thus, at least one of the output channels does not have a light beam separated from the spectral light source at least as long as the output channel is turned off. An example of a light blocking element can be, for example, a shutter placed on an output channel, for example, at the end of the output channel, to turn the output channel off. The light blocking element can be removed from the output channel to turn the output channel on again.

[0030] The spectral light source may be configured to modulate the light beam in at least one of the output channels. The spectral light source may be specifically configured to modulate at least one of the amplitude of the light beam, the frequency of the light beam, and the duty cycle of the light beam. The term "modulate" as used herein is a broad term and should be given its ordinary and customary meaning to those skilled in the art and should not be limited to a special or customized meaning. The term may specifically refer to, but is not limited to, the process of changing, specifically periodically changing, at least one characteristic of the light, specifically one or both of the intensity or phase of the light. As will be appreciated by those skilled in the art, intensity refers to the amplitude of the light. The modulation may be a full modulation from a maximum value to zero, or a partial modulation from a maximum value to an intermediate value greater than zero.

[0031] The spectral light source may in particular be configured to modulate the light beam of each one of the output channels independently. Thus, a first output channel may modulate a first light beam separated via the first output channel differently than a second output channel modulating a second light beam separated via the second output channel. As an example, the first light beam may be modulated at a different frequency than the second light beam. The fact that the light beams may be modulated differently may in particular allow for synchronous measurement of measurement objects on multiple optical paths. Due to the difference in modulation, it may be possible to distinguish the light beams even if they are detected by one and the same detector. The spectral light source may be configured to modulate the amplitude of at least one light beam of the output channels with a frequency of 0 Hz to 1000 Hz, preferably 0.5 Hz to 1000 Hz, more preferably 1 Hz to 500 Hz, even more preferably 8 Hz to 128 Hz.

[0032] The housing may comprise an inner housing at least partially surrounding the light emitting element. The housing may further comprise an outer housing at least partially surrounding the inner housing. The inner housing and the outer housing may each comprise at least two openings as part of the output channels. At least one of the output channels may comprise at least one modulation element for modulating the respective light beam. The modulation element may be arranged in an intermediate space between the inner housing and the outer housing, specifically between the respective openings of the inner housing and the outer housing. The modulation element may thus be shielded by the outer housing from external influences, for example dirt. At the same time, the modulation element may be shielded by the inner housing from heat that may be generated by the light emitting element. This contributes to a longer life of the modulation element as well as a reliable and safe operation.

[0033] The term "modulation element" as used herein is a broad term and should be given its ordinary and customary meaning to those skilled in the art and should not be limited to a special or customized meaning. The term may specifically refer to any element configured to modulate light, without being limited thereto. Specifically, the modulation element may be configured to modulate the amplitude of at least one light beam from a maximum value to a minimum value, specifically zero, by periodically blocking and / or attenuating at least a portion of the intensity of the light beam of one of the output channels. The modulation element may be configured to mechanically modulate the light, for example, by using a rotating chopper wheel, and / or to electronically modulate the light, for example, by using electro-optical and / or acousto-optical effects, for example, by using a Pockels cell and / or a Kerr cell. Further examples regarding the modulation element are described in more detail below. The modulation element may be attached to an inner housing. The electronic circuit may be at least partially enclosed in an outer housing. The housing may include at least one base element. The inner housing and the outer housing may be directly or indirectly mounted on the base element. The electronic circuitry may be housed in the outer housing behind the inner housing. The light emitting element may be attached to the electronic circuitry. The light emitting element may protrude from the electronic circuitry into the inner housing.

[0034] At least one optical element may be disposed inside the outer housing, specifically within at least one of the openings of the inner housing. The optical element may comprise a lens housed in each of the openings of the inner housing. The term "optical element" as used herein is a broad term and should be given its ordinary and customary meaning to those skilled in the art and should not be limited to a special or customized meaning. The term may specifically refer, without limitation, to any element configured to change at least one optical characteristic of incident light, such as the intensity of the light or the direction of at least a portion of the light. The light may be scattered by the optical element. The light may be at least partially reflected and / or absorbed by the optical element.

[0035] The spectroscopic light source may further comprise at least one actuator. The term "actuator" as used herein is a broad term and should be given its ordinary and customary meaning to those skilled in the art and should not be limited to a special or customized meaning. The term may specifically refer to, without limitation, any device configured to exert at least one force and / or at least one action on at least one element and / or to change at least one characteristic of the element. The actuator may specifically be or comprise at least one mechanical actuator configured to exert at least one mechanical action on the element. The at least one mechanical actuator may specifically comprise at least one motor, such as at least one electric motor. The at least one actuator may specifically be or comprise at least one rotary actuator, such as a rotor. In addition to mechanical actuators, other types of actuators are possible, such as one or more of electric actuators, electromechanical actuators, optical actuators, and opto-mechanical actuators. In particular, the actuator may be configured to move at least one element into and / or out of and / or into at least one of the optical channels of the spectral light source. As an example, the actuator may be configured to move at least one optical element, such as an optical filter, into at least one of the output channels. Furthermore, the actuator may be configured to modulate at least one optical beam in at least one of the output channels of the spectral light source.

[0036] The actuator may comprise at least one modulating element, specifically at least one of a shutter and a chopper wheel. The term "shutter" as used herein is a broad term and should be given its ordinary and customary meaning to those skilled in the art and should not be limited to any special or customized meaning. The term may specifically refer to, without limitation, any device configured to block light for a predetermined period of time. The shutter may comprise at least one opaque element movable between at least two different spatial positions, where a different amount of light may be blocked in each of the at least two spatial positions. Specifically, in a first position no light may be blocked and in a second position all light may be blocked. As an example, the opaque element may be a pivotable opaque element, where the opaque element may be configured to pivot between a first position and a second position. The shutter may further comprise at least one of a spring and a catch mechanism. As indicated above, the shutter may also be used to turn on and off at least one of the output channels by moving the shutter in and out of the output channel. Additionally, at least one of the light beams separated via the output channels can be modulated by moving the shutter in and out of the output channel in a predetermined manner, specifically cyclically.

[0037] The term "chopper wheel" as used herein is a broad term and should be given its ordinary and customary meaning to those skilled in the art and should not be limited to any special or customized meaning. The term may specifically refer to, but is not limited to, a rotatable sector aperture configured to modulate light. The chopper wheel may specifically be configured to periodically block light intensity from a maximum value to zero. The sector aperture may comprise at least one opaque sector that blocks all incident light intensity. Specifically, the chopper wheel may be arranged to periodically move at least one opaque sector to at least one of the output channels of the spectral light source during rotation of the chopper wheel. Thus, the amplitude of at least one light beam separated through the output channel may be modulated at a corresponding frequency.

[0038] The actuator may comprise at least one stepper motor. The term "stepper motor" as used herein is a broad term and should be given its ordinary and customary meaning to those skilled in the art and should not be limited to a special or customized meaning. The term may specifically refer to, but is not limited to, an electric motor configured to divide a full revolution of the rotor of the electric motor into a number of individually approachable steps having equal step sizes. In particular, the shutter and / or chopper wheel of the spectral light source may be driven by a stepper motor. Further elements, in particular optical elements, may be moved to at least one of the output channels by using a stepper motor. As indicated above, at least one of the output channels may further comprise at least one optical element, in particular a movable optical element. Thus, the optical element may be configured to be moved into and / or out of and / or into the output channel. The optical element may comprise at least one of a lens, in particular a focusing lens, an aperture, an optical filter, an active element such as a diffraction grating, a dispersive element, a diffraction element, a spatial light modulator, and a mirror.

[0039] At least one of the output channels may comprise a fiber optic connector. The term "optical fiber" as used herein is a broad term and should be given its ordinary and customary meaning to those skilled in the art and should not be limited to a special or customized meaning. The term may specifically refer, without limitation, to an optical waveguide configured to guide light by total internal reflection, specifically a flexible waveguide configured to transmit light between two spatial points, specifically over a longer distance. An optical fiber may optionally include a core material surrounded by at least one cladding material having, for example, a lower refractive index. Thus, light may be guided within the core material due to total internal reflection, for example at one or more boundaries between the core material and the cladding material, as long as, for example, the angle between the light and the boundary is greater than a critical angle. The term "fiber optic connector" as used herein is a broad term and should be given its ordinary and customary meaning to those skilled in the art and should not be limited to a special or customized meaning. The term may specifically refer, without being limited thereto, to any device configured to couple light to or separate light from an optical fiber, specifically to couple light to the core of the optical fiber so that the light is transmitted by the optical fiber. As an example, the optical fiber connector may comprise a holder for holding an end of the optical fiber. Furthermore, the optical fiber connector may comprise at least one optical element, such as at least one lens for focusing the light coupled to the optical fiber to the free end of the optical fiber. The optical fiber connector may specifically be a plug-in optical fiber connector. As an example, the optical fiber connector may be disposed at the end of the output channel of the spectral light source and may separate the light beam from the spectral light source to the optical fiber. The optical fiber connector may be attached to an outer surface of the housing, specifically to an outer surface of the outer housing, more specifically to an outer surface of the outer housing at the location of at least one opening of the outer housing. Specifically, the optical fiber connector may be plugged into the opening of the outer housing.Optionally, the adapter may first be installed in the opening in the outer housing and the fiber optic connector plugged into the adapter.

[0040] An electronic circuit may comprise at least one printed circuit board. The term "printed circuit board" as used herein, often abbreviated as "PCB", is a broad term and should be given its ordinary and customary meaning to those skilled in the art and should not be limited to any special or customized meaning. The term may specifically refer, without limitation, to an electrically non-conductive planar substrate, also called a "substrate", on which at least one sheet of conductive material, in particular a copper layer, is applied, in particular laminated, and further includes one or more electronic, electrical, and / or optical elements. Other terms referring to this type of circuit carrier are printed circuit assembly, abbreviated "PCA", printed circuit board assembly, abbreviated "PCB assembly" or "PCBA", circuit card assembly, abbreviated "CCA", or simply "card". In PCBs, the electrically insulating substrate may include glass epoxy, and cotton paper impregnated with phenolic resin, typically brown or brown, may also be used as the substrate material. Depending on the number of sheets, the printed circuit board can be a single-sided PCB, a two-layer or double-sided PCB, or a multi-layer PCB, the different sheets can be connected to each other by using so-called "vias". A double-sided PCB can have metal on both sides, and a multi-layer PCB can be designed by sandwiching an additional metal layer between further layers of electrically insulating material. Furthermore, by using two double-sided PCBs, a four-layer PCB can be produced. In a multi-layer PCB, the layers can be stacked together in an alternating order: metal, substrate, metal, substrate, metal, etc., each metal layer can be etched separately, and any internal vias can be plated through before the layers are stacked together. Furthermore, the vias can be or comprise copper-plated holes, which can be designed as electrical tunnels through the electrically insulating substrate. For this purpose, through-hole components can also be used, which are usually attached by wire leads that penetrate the substrate and are soldered to tracks or traces on the other side.

[0041] The printed circuit board may comprise at least one sensor configured to monitor in real time at least one of the following: voltage across the light-emitting element; current through the light-emitting element; power supplied to the light-emitting element; resistance of the light-emitting element; temperature of the light-emitting element, and the light-emitting element may be thermally coupled to the sensor. The term "sensor" as used herein is a broad term and should be given its ordinary and customary meaning to those skilled in the art and should not be limited to a special or customized meaning. The term may specifically refer to, but is not limited to, any device configured to detect at least one condition or measure at least one measurement variable. As an example, the sensor may be a thermistor, specifically a negative temperature coefficient (NTC) thermistor, and may be thermally coupled to the light-emitting element via at least one thermally conductive material, such as copper. Furthermore, the sensor may comprise, for example, at least one of a voltmeter, an ammeter, a wattmeter, and an ohmmeter. The sensor may specifically be configured to indirectly monitor the light-emitting element, for example, by measuring a voltage drop across a power supply voltage and a small predefined series resistance. Further physical quantities, such as power, current and / or resistance, may be derived from the measurements.

[0042] The electronic circuitry may comprise at least one interface, such as a wireless and / or wired electronic or electrical interface, in particular a USB port accessible from the exterior of the housing. The term "interface" as used herein is a broad term and should be given its ordinary and customary meaning to those skilled in the art and should not be limited to a special or customized meaning. The term may refer in particular, without limitation, to any device forming a boundary configured to transfer information. In particular, the interface may be configured to transfer information from a computing device, e.g., a computer, e.g., to transmit or output information on another device. Additionally or alternatively, the interface may be configured to transfer information to a computing device, e.g., a computer, e.g., to receive information. The communication interface may in particular provide a means for transferring or exchanging information. In particular, the interface may provide a data transfer connection, e.g., Bluetooth, NFC, inductive coupling, etc. By way of example, the interface may be or comprise at least one port, including one or more of a network or Internet port, a USB port, and a disk drive. The interface may be at least one web interface. In particular, data transfer between the electronic circuit and at least one external device, such as a computer, tablet or smartphone, may be possible via the interface. As an example, sensor data may be transferred from the electronic circuit to the external device via the interface. As a further example, commands for controlling the electronic circuit, such as commands for generating at least one electrical output of the electronic circuit, such as power, especially voltage, may be transferred from the external device via the interface.

[0043] The electronic circuit may comprise at least one controller, specifically at least one microcontroller. The controller may be configured to control at least one of the powers applied to the light-emitting elements. The controller may be configured to control at least one of the output channels. The controller may be configured to control the sensor and / or the interface. The term "controller" as used herein is a broad term and should be given its ordinary and customary meaning to those skilled in the art and should not be limited to a special or customized meaning. The term may specifically refer to, but is not limited to, any electronic device configured to control one or more operations of a spectral light source or a part of a spectral light source. The controller may be programmable. Thus, the controller may specifically comprise at least one processor. The term "processor" as used herein is a broad term and should be given its ordinary and customary meaning to those skilled in the art and should not be limited to a special or customized meaning. The term may specifically refer to, but is not limited to, any logic circuit configured to perform the basic operations of a computer or system, and / or generally, a device configured to perform calculations or logical operations. In particular, the processor may be configured to process basic instructions that drive a computer or system. As an example, the processor may comprise at least one arithmetic logic unit (ALU), at least one floating point unit (FPU), such as a mathematical coprocessor or numeric coprocessor, a number of registers, in particular registers configured to provide operands to the ALU and store operation results, and memories, such as L1 and L2 cache memories. In particular, the processor may be a multi-core processor. In particular, the processor may be or comprise a central processing unit (CPU). Additionally or alternatively, the processor may be or comprise a microprocessor, and thus in particular the elements of the processor may be included in one single integrated circuit (IC) chip.Additionally or alternatively, the processor may be or may comprise one or more application specific integrated circuits (ASICs) and / or one or more field programmable gate arrays (FPGAs).

[0044] As indicated above, the controller may be configured to control at least one of the power applied to the light-emitting element, specifically the voltage applied to the light-emitting element. As a result, the controller may be configured to control the light emission of the light-emitting element, specifically according to the user's specifications of the spectral light source. The controller may be configured to use a look-up table for matching the power applied to the light-emitting element and the light emission of the light-emitting element. As an example, the light-emitting element may be an incandescent lamp. The controller may control the power applied to the incandescent lamp and thus the temperature of the incandescent lamp. As a result, the controller may control the intensity and the spectral distribution of the thermal radiation emitted by the incandescent lamp. The relationship between the power applied to the incandescent lamp and the temperature of the incandescent lamp may be known from a calibration measurement and may be recorded in a look-up table. Furthermore, the relationship between the temperature of the incandescent lamp and the intensity or the spectral distribution of the thermal radiation emitted by the incandescent lamp may be known from a calibration measurement and may be recorded in a look-up table.

[0045] The controller may be configured to perform a soft start and / or a soft stop of the light-emitting elements. The term "soft start" as used herein is a broad term and should be given its ordinary and customary meaning to those skilled in the art and should not be limited to a special or customized meaning. The term may specifically refer to, but is not limited to, a means for power control when the device is switched on. The means may be configured to prevent overloading of the device. The means may specifically limit a potentially large inrush current of the device. As an example, when switching on the light-emitting elements of a spectral light source, a voltage ramp may be applied to the light-emitting elements over a period of time from zero to a target voltage for operation. The voltage ramp may be applied over a period of time that varies from 1 second to 60 seconds, preferably from 2 seconds to 30 seconds, more preferably from 3 seconds to 10 seconds. Similarly, the term "soft stop" as used herein is a broad term and should be given its ordinary and customary meaning to those skilled in the art and should not be limited to a special or customized meaning. The term may specifically refer to, but is not limited to, a means for power control when the device is switched off. Specifically, a reverse voltage ramp may be applied compared to the voltage ramp of the soft start. The soft start and / or soft stop may specifically reduce the operating stress of the light-emitting element of the spectral light source. Thus, the soft start and / or soft stop may increase the life of the light-emitting element. Furthermore, when using the soft start and / or soft stop, the heat-up time of the light-emitting element, which must be waited until the light-emitting element is stable, may be avoided.

[0046] The controller may include at least one buck regulator. The buck regulator may include at least one feedback connection. The term "buck regulator" as used herein is a broad term and should be given its ordinary and customary meaning to those skilled in the art and should not be limited to any special or customized meaning. The term may specifically refer, without limitation, to a DC-DC converter configured to modify at least one input voltage to at least one output voltage less than or equal to the input voltage. Above and below, DC refers to direct current. The buck regulator may include at least one of a transistor, a diode, an inductor, and a capacitor. As an example, a buck regulator may receive an input voltage, step down the input voltage to a variable target voltage, and provide the target voltage as an output voltage.

[0047] The controller may include at least one resistor network. As used herein, the term "network" is a broad term and should be given its ordinary and customary meaning to one skilled in the art and should not be limited to any special or customized meaning. The term may specifically refer to, without limitation, a group of at least partially interconnected components. As used herein, the term "resistance network" is a broad term and should be given its ordinary and customary meaning to one skilled in the art and should not be limited to any special or customized meaning. The term may specifically refer to, without limitation, a network comprising at least one resistor. The resistor may be grounded. The resistive network may specifically comprise a plurality of resistors and wires and / or traces for at least partially interconnecting the resistors. The resistive network or at least a portion of the resistive network may form at least one voltage divider. The controller may include at least one digital-to-analog converter (DAC). The digital-to-analog converter may be grounded. The digital-to-analog converter may be configured to control the modification of the input voltage by the buck regulator. Specifically, the digital-to-analog converter may be connected to a resistor network, which may further be connected to at least a feedback connection of the buck regulator, such that the digitally controlled output voltage of the digital-to-analog converter may be summed to the feedback connection of the buck regulator.

[0048] The controller may include at least one shunt. The shunt may include at least one of a voltmeter and a current meter. The term "shunt" as used herein is a broad term and should be given its ordinary and customary meaning to those skilled in the art and should not be limited to a special or customized meaning. The term may specifically refer, without limitation, to any device configured to form a low resistance bypass for a current. In particular, the shunt may be configured for current sensing and / or voltage sensing. As an example, the shunt may include a shunt resistor in parallel with a shunt voltmeter.

[0049] The spectral light source may comprise at least one cooling device, specifically at least one of a fan and a heat sink. The term "cooling device" as used herein is a broad term and should be given its normal and customary meaning to those skilled in the art and should not be limited to a special or customized meaning. The term may specifically refer to any device configured to extract thermal energy from at least one object, without being limited thereto. The cooling device may be configured to dissipate heat from the object. The cooling device may thus be configured to keep the temperature of the object stable. The cooling device may be configured to actively reduce the temperature of the object. The light-emitting element, the electronic circuitry and the cooling device may be spatially separated. This may in particular facilitate shielding the light-emitting element and / or the electronic circuitry from environmental influences, e.g. dirt or dust, which may be particularly important for explosion protection. This may provide a high level of protection for the spectral light source, up to complete immersion in water.

[0050] In a further aspect of the present invention, a spectroscopic measurement system is proposed. The term "system" as used herein is a broad term and should be given its ordinary and customary meaning to those skilled in the art and should not be limited to a special or customized meaning. The term may specifically, without limitation, refer to any collection of interacting or interdependent components or parts that form a whole. In particular, the components may interact with each other to perform at least one common function. At least two components may be treated independently or may be combined or connectable. The term "spectroscopic measurement system" as used herein is a broad term and should be given its ordinary and customary meaning to those skilled in the art and should not be limited to a special or customized meaning. The term may specifically, without limitation, refer to a system configured for spectroscopic measurement.

[0051] The spectroscopic measurement system comprises at least one spectroscopic light source according to any one of the embodiments described above or in further detail below. The spectroscopic measurement system further comprises at least one detector. The detector is configured to detect at least one light beam separated from the spectroscopic light source. The detector is further configured to generate at least one corresponding detector signal. The term "detector" as used herein is a broad term and should be given its ordinary and customary meaning to those skilled in the art and should not be limited to a special or customized meaning. The term may specifically refer to any device capable of detecting light qualitatively and / or quantitatively, without being limited thereto. Thus, specifically, the detector may comprise at least one sensitive element capable of changing at least one measurable characteristic in response to irradiation with light. The detector may specifically comprise one or more of a photodiode, a phototransistor, a photoresistor, a semiconductor sensor, a photomultiplier tube, a phototube, a thermal detector, a pyroelectric detector, a thermopile, a bolometer, a Golay cell, and a photochemical sensor. The detector may be a single detector having a single uniform sensitive element or surface, or may be a detector having multiple sensitive elements, such as a pixelated sensor, e.g., a CCD or CMOS device. The detector may comprise at least one optical pass filter, in particular selected from at least one of an optical short pass filter, an optical long pass filter, or an optical band pass filter. The optical pass filter may be configured to transmit light having a wavelength within a limited wavelength range.

[0052] The spectroscopic measurement system comprises at least one readout electronics configured to read out the detector signal. The term "readout electronics" as used herein is a broad term and should be given its ordinary and customary meaning to those skilled in the art and should not be limited to a special or customized meaning. The term may specifically refer to, but is not limited to, any device configured for at least one of receiving, monitoring, interpreting, and pre-processing the detector signal generated by the detector. The readout electronics may specifically be configured to generate a digital signal corresponding to the detector signal, which may be suitable for further computational processing. The readout electronics may comprise at least one readout integrated circuit configured to accumulate the photocurrent. The readout electronics may specifically comprise at least one digital readout integrated circuit, more specifically at least one digital pixel readout integrated circuit.

[0053] The readout electronics may comprise at least one lock-in amplifier configured to amplify the detector signal. The term "lock-in amplifier" as used herein is a broad term and should be given its usual and customary meaning to those skilled in the art and should not be limited to a special or customized meaning. The term may refer in particular, without limitation, to any device configured to extract and amplify a measurement signal having at least one known characteristic from a potentially very noisy environment. In particular, the lock-in amplifier may be configured to extract and amplify a modulated measurement signal, more particularly a measurement signal modulated with a known frequency. As an example, the measurement signal may be modulated with a periodic signal having a known frequency. In this case, the periodic signal may be mixed with the measurement signal in the lock-in amplifier and the mixed signal may be filtered by using at least one low-pass filter. Other lock-in amplifier techniques that take into account periodic modulation are generally known and can be used here. Such lock-in amplifier techniques make it possible to distinguish between different signals, in particular differently modulated signals, detected by one and the same detector. Furthermore, detector noise can be significantly reduced and signal to noise ratios improved, thus improving interferometric measurements such as, for example, FTIR or white light spectroscopy.

[0054] The spectroscopic measurement system comprises at least one evaluation device configured to determine at least one item of information based on the detector signal. The term "evaluation device" as used herein is a broad term and should be given its usual and customary meaning for a person skilled in the art and should not be limited to a special or customized meaning. The term may in particular refer to any device configured to analyze and / or interpret data, without being limited thereto. The evaluation device may be or comprise one or more integrated circuits, in particular at least one application specific integrated circuit (ASIC), and / or data processing device, in particular at least one digital signal processor (DSP), field programmable gate array (FPGA), microcontroller, microcomputer or computer. Alternatively or additionally, the evaluation device may in particular be included by at least one electronic communication unit, in particular a smartphone or tablet. Additional components are possible, in particular one or more pre-processing devices and / or data acquisition devices, in particular one or more devices for receiving and / or pre-processing the detector signal, in particular one or more AD converters and / or one or more filters. Furthermore, the evaluation device may comprise one or more data storage devices, in particular for storing at least one electronic table, in particular at least one look-up table. Furthermore, the evaluation device may be equipped with one or more interfaces, in particular one or more wireless interfaces and / or one or more wired interfaces.

[0055] The evaluation device may be configured to implement and / or execute at least one computer program, in particular at least one computer program that executes or supports a step of generating an information item. By way of example, one or more algorithms may be implemented that perform a transformation on the information item by using the spectrometer signal as at least one input variable. For this purpose, the evaluation device may comprise at least one data processing device, in particular an electronic data processing device, that may be configured to generate the information item by evaluating at least one detector signal. In this way, the evaluation device may be configured to use the detector signal as an input variable and to generate the information item by processing the input variables. This processing may be performed in parallel, in succession or in combination. The evaluation device may use any process, in particular by calculation and / or by using at least one stored and / or known relationship, to generate the item information.

[0056] The term "information item" as used herein is a broad term and should be given its ordinary and customary meaning to those skilled in the art and should not be limited to a special or customized meaning. The term may specifically refer to at least one of data, knowledge, or evidence providing a qualitative and / or quantitative description of at least one entity, such as, but not limited to, a physical property of an element or object. The information item may refer, for example, to the chemical composition of a substance. As an example, a spectroscopic measurement system may be used to analyze at least one substance. In such a case, at least one detector may, for example, detect the transmission of at least one light beam through the material at at least one wavelength. From at least one corresponding detector signal, an absorption spectrum of the material may be derived in the evaluation device, which may be characteristic of a particular chemical composition.

[0057] In a further aspect of the invention, a method for operating a spectroscopic measurement system according to any one of the embodiments described above or in further detail below is proposed, said method comprising the following method steps: a) applying power, in particular at least one voltage, to a light-emitting element of a spectroscopic light source by using an electronic circuit; b) illuminating by using a light emitting element; c) isolating at least one light beam from the spectral light source by using at least one output channel of the at least two output channels while independently controlling each of the output channels; d) illuminating at least one measurement object with the light beam; e) detecting the light beam by using a detector of the spectroscopic measurement system and generating at least one corresponding detector signal; f) reading out the detector signal by using the readout electronics of the spectroscopic measurement system; g) determining at least one item of information based on the detector signal by using an evaluation device of the spectroscopic measurement system; Includes.

[0058] The method steps a) to g) can be performed in a given order. However, it should be noted that different orders are also possible. Furthermore, one or more method steps may be performed once or repeatedly. Furthermore, two or more method steps may be performed simultaneously or with overlapping time. The method may also include further method steps not listed. In step f), the detector signal may be further amplified by using a lock-in amplifier.

[0059] In step c), the controlling may include turning on and off at least one of the output channels. The controlling may include modulating the light beam in at least one of the output channels, in particular modulating at least one of the amplitude of the light beam, the frequency of the light beam, and the duty cycle of the light beam. The controlling may include modulating the amplitude of the light beam in at least one of the output channels with a frequency between 0 Hz and 1000 Hz, preferably between 0.5 Hz and 1000 Hz, more preferably between 1 Hz and 500 Hz, more preferably between 8 Hz and 128 Hz.

[0060] In step c), at least two light beams can be separated from the spectral light source. Each light beam may be separated via a different output channel of the spectral light source. In step d), the measurement object can be illuminated by at least one of the at least two light beams. At least one light beam of the at least two light beams can be used as a reference in determining the information item in step g). The spectroscopic measurement system can comprise at least one element configured to combine the two light beams. The term "reference" as used herein is a broad term and should be given its ordinary and customary meaning to a person skilled in the art and should not be limited to a special or customized meaning. The term may refer to any entity suitable for comparison purposes, in particular, without limitation, in relation to the measured signal. The comparison of the measurement signal with the reference signal can in particular facilitate further processing and / or evaluation of the measurement signal. In particular, the difference between the measurement signal and the reference can be used for further processing and / or evaluation of the measurement signal. As an example, the measurement object can be illuminated by a first light beam and the second light beam can be sent directly to the detector. However, it is also possible to send at least two light beams to the measurement object, which allows for synchronous spectroscopic measurements of the measurement object.

[0061] In step c), independently controlling the output channels may comprise modulating at least one light beam in the respective output channel differently from at least one remaining light beam in at least one remaining output channel. In particular, the two differently modulated light beams may be distinguishable when detected by one and the same detector. As an example, the first light beam may be separated via the first output channel. In the first output channel, the amplitude of the first light beam may be modulated at a first frequency, for example by using a first chopper wheel. At the same time, the second light beam may be separated via the second output channel. In the second output channel, the amplitude of the second light beam may be modulated at a second frequency, for example by using a second chopper wheel. The first chopper wheel and the second chopper wheel may in particular be operated at different rotation frequencies, and the first chopper wheel and the second chopper wheel may be of the same design. It may therefore be possible to detect the first light beam and the second light beam with one and the same detector, distinguishing between them due to the difference in modulation depth.

[0062] The method may be computer-implemented. With reference to the computer-implemented aspects of the present invention, one or more of the method steps, or even all of the method steps, of the method according to one or more of the embodiments disclosed herein may be performed by using a computer or a computer network. Thus, in general, any of the method steps involving providing and / or manipulating data may be performed by using a computer or a computer network. In general, these method steps may include any method steps, except for those that typically require manual work.

[0063] The device and method according to the invention may offer a number of advantages over known devices and methods. In particular, the spectral light source can be configured to simultaneously provide several individually adapted high-power light beams for spectroscopic measurements. The light beams may be free beams or may be fiber-coupled. The light beams may each be of a single wavelength or may extend over a wider spectral range, in particular the infrared spectral range. Nevertheless, the spectral light source in principle requires only one light-emitting element, for example a ready-made incandescent light bulb, and does not require beam splitters or further optical elements. This keeps the constructional complexity of the spectral light source low and saves constructional space. With two or more output channels, the spectral light source can furthermore automatically be equipped with a built-in reference channel. Moreover, in order to save measurement time, several measurements can be performed simultaneously by using different output channels. Since the light beams can be individually adapted in the output channels of the spectral light source, they can also in particular be modulated individually. If the different light beams are modulated with different modulation frequencies, the light beams can be detected with one and the same detector of the spectroscopic measurement system while being differentiated from one another. For this, the common lock-in amplifier technique can be used. Modulation further helps by reducing detector noise, facilitating a good signal-to-noise ratio.

[0064] Furthermore, thanks to the option of active stabilization, the spectral light source can be configured to provide a very stable light beam both in the short and long term. Among them, switching the spectral light source on and off generally does not affect the stability. Stress on the light-emitting element can be significantly reduced by soft start and soft stop. Thanks to this solution, the spectral light source may generally not require a heat-up time for the light-emitting element to operate stably. Since the user no longer has to wait for the heat-up time to elapse before making a reliable measurement, he is more likely to switch off the spectral light source after each measurement if it is no longer needed, instead of leaving it on for a long time. At the same time, multiple sensors can monitor the light-emitting element live and directly trigger the correction of potential failures. All this can significantly extend the life of the light-emitting element.

[0065] Furthermore, the light emitting element, the electronic circuit and the cooling device may be spatially separated in the spectral light source. This allows, in particular, to keep the optics and electronics clean by preventing contact with the external environment. This may be important in dirty or dusty environments, in particular with regard to explosion protection. In this way, the spectral light source may be fully encapsulated and suitable for use in hazardous locations. Furthermore, the spectral light source may provide a high level of protection, for example up to full immersion in water. The housing, which may in particular comprise an inner housing and an outer housing, may facilitate this property. The sensitive element may be arranged in the housing for protection. For even better protection, it may be arranged between the inner and outer housings. Thus, through the inner housing, it may be protected from electromagnetic radiation, in particular from the heat emitted by the light emitting element, and at the same time through the outer housing, it may be protected from external influences.

[0066] A further advantage of the spectroscopic light source proposed here refers to the above-mentioned drawback of continuous measurements regarding short-term fluctuations that lead to noise addition. A two-channel or multi-output channel setup as currently proposed can preferably compensate for this effect by allowing parallel measurements of reference and sample. The noise is usually the same in both output channels and paths and therefore does not add up.

[0067] In summary, without excluding further possible embodiments, the following embodiments can be envisaged: Embodiment 1: - at least one luminous element; - at least one electronic circuit configured to apply power, in particular a voltage, to said light-emitting element; - at least one housing, said housing at least partially enclosing said light emitting element; - at least two output channels extending through the housing, each of the output channels configured to separate at least one light beam from a spectral light source; Equipped with The spectral light source is configured to independently control each of the output channels.

[0068] Embodiment 2: The spectral light source according to the preceding embodiment, wherein the light emitting element comprises at least one incandescent lamp, specifically at least one halogen filled incandescent lamp.

[0069] Embodiment 3: The spectroscopic light source of any one of the preceding embodiments, wherein the housing at least partially encloses electronic circuitry.

[0070] Embodiment 4: The spectral light source of any one of the preceding embodiments, wherein the spectral light source is configured to turn on and off at least one of the output channels.

[0071] Embodiment 5: A spectral light source as described in any one of the preceding embodiments, wherein the spectral light source is configured to modulate the light beam in at least one of the output channels, specifically to modulate at least one of the amplitude of the light beam, the frequency of the light beam, and the duty cycle of the light beam, specifically to independently modulate the light beam in each of the output channels.

[0072] Embodiment 6: A spectral light source according to any one of the preceding embodiments, wherein the spectral light source is configured to modulate the amplitude of the light beam of at least one of the output channels at a frequency of 0 Hz to 1000 Hz, preferably 0.5 Hz to 1000 Hz, more preferably 1 Hz to 500 Hz, and even more preferably 8 Hz to 128 Hz.

[0073] Embodiment 7: A spectral light source as described in any one of the preceding embodiments, wherein the housing comprises an inner housing at least partially surrounding the light-emitting element, the housing further comprising an outer housing, the outer housing at least partially surrounding the inner housing, and the inner housing and the outer housing each comprising at least two openings as part of the output channel.

[0074] Embodiment 8: A spectroscopic light source as described in the preceding embodiment, wherein at least one of the output channels comprises at least one modulation element for modulating the respective light beam, the modulation element being disposed in an intermediate space between the inner housing and the outer housing, specifically between the respective openings of the inner housing and the outer housing.

[0075] Embodiment 9: A spectroscopic light source as described in the preceding embodiment, wherein the modulation element is attached to the inner housing.

[0076] Embodiment 10: The spectroscopic light source of any one of the preceding three embodiments, wherein the electronic circuitry is at least partially enclosed by the outer housing.

[0077] Embodiment 11: A spectroscopic light source described in any one of the preceding four embodiments, wherein the housing comprises at least one base element, and the inner housing and the outer housing are mounted directly or indirectly on the base element.

[0078] Embodiment 12: A spectroscopic light source as described in the preceding embodiment, wherein the electronic circuit is housed within the outer housing below the inner housing, and the light-emitting element is attached to the electronic circuit, and the light-emitting element protrudes from the electronic circuit into the inner housing.

[0079] Embodiment 13: A spectroscopic light source described in any one of the preceding six embodiments, wherein at least one optical element is disposed inside the outer housing, specifically within at least one of the openings of the inner housing.

[0080] Embodiment 14: A spectral light source as described in the preceding embodiment, wherein the optical element comprises a lens housed in each of the openings of the inner housing.

[0081] Embodiment 15: The spectral light source of any one of the preceding embodiments, wherein the spectral light source further comprises at least one actuator.

[0082] Embodiment 16: A spectral light source as described in the preceding embodiment, wherein the actuator comprises at least one modulation element, specifically at least one of a shutter and a chopper wheel.

[0083] Embodiment 17: A spectroscopic light source described in any one of the previous two embodiments, wherein the actuator comprises at least one stepping motor.

[0084] Embodiment 18: A spectral light source according to any one of the preceding embodiments, wherein at least one of the output channels further comprises at least one optical element, in particular a movable optical element.

[0085] Embodiment 19: A spectral light source as described in the preceding embodiment, wherein the optical element comprises at least one of a lens, in particular a focusing lens, an aperture, an optical filter, a diffraction grating, a dispersive element, a diffractive element, an active element such as a spatial light modulator, and a mirror.

[0086] Embodiment 20: A spectroscopic light source according to any one of the preceding embodiments, wherein at least one of the output channels comprises an optical fiber connector.

[0087] Embodiment 21: A spectroscopic light source as described in the preceding embodiment, wherein the optical fiber connector is attached to the outer surface of the housing, specifically the outer surface of the outer housing, more specifically the outer surface of the outer housing at the position of at least one opening of the outer housing.

[0088] Embodiment 22: A spectroscopic light source according to any one of the preceding embodiments, wherein the electronic circuit comprises at least one printed circuit board.

[0089] Embodiment 23: The spectroscopic light source described in the preceding embodiment, wherein the printed circuit board comprises at least one sensor configured to monitor in real time at least one of: the voltage across the light-emitting element; the current through the light-emitting element; the power supplied to the light-emitting element; the resistance of the light-emitting element; and the temperature of the light-emitting element, and the light-emitting element is thermally coupled to the sensor.

[0090] Embodiment 24: A spectroscopic light source described in any one of the preceding embodiments, wherein the electronic circuitry comprises at least one interface, in particular a USB port, accessible from outside the housing.

[0091] Embodiment 25: A spectroscopic light source described in any one of the preceding embodiments, wherein the electronic circuit comprises at least one controller, specifically at least one microcontroller, configured to control at least one of the powers applied to the light-emitting elements, at least one of the output channels, and optionally the sensor and the interface.

[0092] Embodiment 26: The spectral light source described in the preceding embodiment, wherein the controller is configured to perform soft starting and / or soft stopping of the light emitting element.

[0093] Embodiment 27: A spectroscopic light source described in any one of the preceding two embodiments, wherein the controller comprises at least one of a step-down regulator with a feedback connection, a resistor network, a digital-to-analog converter (DAC), and a shunt with at least one of a voltmeter and an ammeter.

[0094] Embodiment 28: A spectral light source described in any one of the preceding embodiments, wherein the spectral light source further comprises at least one cooling device, specifically at least one of a fan and a heat sink.

[0095] Embodiment 29: A spectroscopic light source according to any one of the preceding embodiments, wherein the light emitting element, the electronic circuit, and optionally the cooling device are spatially separated.

[0096] Embodiment 30: - at least one spectral light source according to any one of the preceding embodiments; - at least one detector configured to detect at least one separated light beam from the spectral light source and further configured to generate at least one corresponding detector signal; - at least one readout electronics configured to read out said detector signal; - at least one evaluation device configured to determine at least one item of information on the basis of said detector signal; A spectroscopic measurement system comprising:

[0097] Embodiment 31: A spectroscopic measurement system as described in the preceding embodiment, wherein the readout electronics comprises at least one lock-in amplifier configured to amplify the detector signal.

[0098] Embodiment 32: A method of operating a spectroscopic measurement system according to any one of the preceding embodiments referring to a spectroscopic measurement system, the method comprising: a) applying power, in particular at least one voltage, to a light-emitting element of a spectroscopic light source by using an electronic circuit; b) generating light by using said light emitting element; c) isolating at least one light beam from said spectral light source by using at least one output channel of the at least two output channels while independently controlling each one of the output channels; d) illuminating at least one measurement object with said light beam; e) detecting the light beam by using a detector of the spectroscopic measurement system and generating at least one corresponding detector signal; f) reading out the detector signal by using readout electronics of the spectroscopic measurement system; g) determining at least one item of information based on the detector signal by using an evaluation device of the spectroscopic measurement system; A method comprising:

[0099] Embodiment 33: The method of any preceding embodiment, wherein in step c), controlling includes turning on and off at least one of the output channels.

[0100] Embodiment 34: A method according to any one of the preceding embodiments referring to a method, wherein in step c), the controlling includes modulating the light beam in at least one of the output channels, specifically modulating at least one of the amplitude of the light beam, the frequency of the light beam, and the duty cycle of the light beam.

[0101] Embodiment 35: The method of any one of the preceding embodiments referring to the method, wherein in step c), the controlling comprises modulating the amplitude of the light beam in at least one of the output channels at a frequency between 0 Hz and 1000 Hz, preferably between 0.5 Hz and 1000 Hz, more preferably between 1 Hz and 500 Hz, more preferably between 8 Hz and 128 Hz.

[0102] Embodiment 36: A method according to any one of the preceding embodiments referring to a method, wherein in step c), at least two light beams are separated from the spectral light source, each light beam being separated via a different output channel of the spectral light source, and in step d), the measurement object is illuminated by at least one of the at least two light beams.

[0103] Embodiment 37: The method according to the preceding embodiment, wherein at least one light beam of the at least two light beams is used as a reference in determining the information item in step g).

[0104] Embodiment 38: A method according to any one of the preceding two embodiments, wherein in step c) independently controlling the output channels includes modulating at least one light beam in each of the output channels differently from at least one remaining light beam in at least one remaining output channel.

[0105] Embodiment 39: The method according to any one of the preceding embodiments referring to a method, wherein the method is computer-implemented. [Brief description of the drawings]

[0106] Further optional features and embodiments are disclosed in more detail in the description of the following embodiments, preferably in conjunction with the dependent claims, where each optional feature can be realized in any possible combination as well as in a separate manner, as understood by a person skilled in the art. The scope of the present invention is not limited by the preferred embodiments. The embodiments are illustrated diagrammatically in the figures, where identical reference numbers in these figures refer to identical or functionally equivalent elements. [Figure 1] FIG. 1 illustrates a schematic diagram of an exemplary embodiment of a spectroscopic measurement system. [Diagram 2] FIG. 2 illustrates an exemplary embodiment of a spectroscopic light source in an exploded view. [Diagram 3] FIG. 2 is a schematic circuit diagram illustrating one embodiment of a controller that controls the power applied to the light-emitting elements of the spectral light source. [Figure 4] 4A-4E show experimental results of stability measurements for one embodiment of a spectral light source. [Diagram 5] 1 shows a flow chart of one embodiment of a method of operating a spectroscopic measurement system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0107] Detailed Description of the Preferred Embodiments Fig. 1 shows a schematic representation of an embodiment of a spectroscopic measurement system 110. The spectroscopic measurement system 110 comprises at least one spectral light source 112, which will be described in more detail below with reference to Fig. 2. The spectroscopic measurement system 110 further comprises at least one detector 114. The detector 114 is configured to detect at least one light beam 116 separated from the spectral light source 112. The detector 114 is further configured to generate at least one corresponding detector signal. The spectroscopic measurement system 110 further comprises at least one readout electronics 118 configured to read out the detector signal. The spectroscopic measurement system 110 further comprises at least one evaluation device 120 configured to determine at least one item of information based on the detector signal.

[0108] As shown in FIG. 1, the spectroscopic light source 112 may be configured to generate two light beams 116, for example, a measurement light beam 122 and a reference light beam 124. The measurement light beam 122 may be used to illuminate a measurement object 126, such as a sample. The measurement light beam 122 may be scattered at the measurement object 126. In particular, at least a portion of the intensity of the measurement light beam 122 may be absorbed by the measurement object 126. This absorption may be characteristic of at least one physical property of the measurement object 126, for example, a chemical composition of the measurement object 126. At least a portion of the intensity of the measurement light beam 122 may be transmitted through the measurement object 126 to reach the detector 114. The reference light beam 124 may be illuminated toward the detector 114 without interacting with the measurement object 126. The spectroscopic measurement system 110 may be configured to distinguish between the measurement light beam 122 and the reference light beam 124. In particular, the measurement light beam 122 and the reference light beam 124 may be independently modulated by the spectral light source 112 to render them distinguishable. As an example, the measurement light beam 122 and the reference light beam 124 may be modulated by the spectral light source 112 at different frequencies.

[0109] The detector 114 may be connected to at least the readout electronics 118, for example by wireless and / or wired connection. The readout electronics 118 may be configured to generate a digital signal corresponding to the detector signal, which may be suitable for further computational processing. The readout electronics 118 may comprise at least one lock-in amplifier 127. The lock-in amplifier 127 may extract and amplify the at least one detector signal according to a predefined modulation. The lock-in amplifier 127 may further be connected to at least the spectroscopic light source 112, for example by wireless and / or wired connection. The spectroscopic light source 112 may be configured to transfer information about the modulation of the light beam 116 to the lock-in amplifier 127. In particular, the spectroscopic light source 112 may be configured to transfer the modulation frequency of the light beam 116 to the lock-in amplifier 127, for example by using at least one reference signal. The phase of the reference signal may be synchronized to the phase of the measured detector signal, for example by using a phase shift. The lock-in amplifier 127 may be connected to the evaluation device 120, for example via a wireless connection and / or a wired connection. The lock-in amplifier 127 may be configured to transfer at least one amplified detector signal, for example an amplified detector signal corresponding to the measurement light beam 122 and / or an amplified detector signal corresponding to the reference light beam 124, to the evaluation device 120. The evaluation device 120 may be configured to process and / or compare the amplified detector signals, for example to calculate their difference and / or quotient. From this, the evaluation device 120 can determine at least one item of information, for example regarding the chemical composition of the measurement object 126.

[0110] 2 shows an embodiment of the spectral light source 112 in an exploded view. The spectral light source 112 comprises at least one light-emitting element 128. The light-emitting element 128 may be configured to emit light isotropically in all spatial directions, in particular by thermal heating. The light-emitting element 128 may comprise at least one incandescent lamp 130, in particular at least one halogen-filled incandescent light bulb 132. The thermal heating may in particular be induced by applying electrical power to at least one filament of the halogen-filled incandescent light bulb 132. The light-emitting element 128 may therefore comprise at least one electrical connection, in particular at least one socket 134. The socket 134 may further at least partially mechanically hold the light-emitting element 128.

[0111] The spectroscopic light source 112 includes at least one electronic circuit 136. The electronic circuit 136 is configured to apply power, specifically a voltage, to the light-emitting element 128. The electronic circuit 136 may include at least one printed circuit board 138. The printed circuit board 138 may include at least one sensor 140. The sensor 140 may be configured to monitor at least one of the following in real time: a voltage across the light-emitting element 128, a current through the light-emitting element 128, a power supplied to the light-emitting element 128, a resistance of the light-emitting element 128, and a temperature of the light-emitting element 128, and the light-emitting element 128 may be thermally coupled to the sensor. As an example, the sensor 140 may be a thermistor, specifically a negative temperature coefficient (NTC) thermistor, and may be thermally coupled to the light-emitting element 128 via at least one thermally conductive material, for example, copper. Furthermore, the sensor 140 may include at least one of, for example, a voltmeter, an ammeter, a wattmeter, and an ohmmeter. The electronic circuitry 136 may further comprise at least one interface 142, specifically a USB port 144. The electronic circuitry 136 may further comprise at least one controller 146, specifically at least one microcontroller 148. Specifically, the printed circuit board 138 may at least partially comprise the controller 146. The controller 146 may be configured to control the interface 142. The controller 146 may be configured to control the power applied to the light emitting elements 128, as will be described in more detail below with reference to FIG. 3.

[0112] The spectroscopic light source 112 comprises at least one housing 150. The housing 150 at least partially surrounds the light emitting element 128. The housing 150 can at least partially surround the entire electronic circuit 136 or at least a portion thereof. The sensitive components of the electronic circuit 136 can be disposed inside the housing 150, for example on a printed circuit board 138. One or more components can optionally be disposed outside the housing, for example on at least one power source 152. The housing 150 can comprise at least one cable feedthrough 154 for connecting components of the electronic circuit 136 inside the housing 150 to components of the electronic circuit 136 outside the housing 150. The USB port 144 of the electronic circuit 136 can be accessible from outside the housing 150, for example through the cable feedthrough 154.

[0113] The spectral light source 112 comprises at least two output channels 156 through a housing 150. Each of the output channels 156 is configured to separate at least one light beam 116 from the spectral light source 112. Each of the output channels 156 may comprise at least one opening 158 in the housing 150 of the spectral light source 112. The housing 150 may be configured to block light emitted by the light-emitting element 128 such that light can exit the spectral light source 112 only through the openings 158 of the output channels 156.

[0114] The spectral light source 112 is configured to independently control each of the output channels 156. The controller 146 may be configured to control at least one of the output channels 156. The spectral light source 112 may be configured to turn on and off at least one of the output channels 156. The spectral light source 112 may be configured to modulate the light beam 116 in at least one of the output channels 156, specifically, to modulate at least one of the amplitude of the light beam 116, the frequency of the light beam 116, and the duty cycle of the light beam 116, specifically, to independently modulate the light beam 116 in each of the output channels 156. The spectral light source 112 may be configured to modulate the amplitude of the light beam 116 in at least one of the output channels 156, specifically, at a frequency between 0 Hz and 1000 Hz, preferably between 0.5 Hz and 1000 Hz, more preferably between 1 Hz and 500 Hz, and even more preferably between 8 Hz and 128 Hz.

[0115] The housing 150 may comprise an inner housing 160 at least partially surrounding the light emitting element 128. The housing 150 may further comprise an outer housing 162 at least partially surrounding the inner housing 160. The inner housing 158 and the outer housing 162 may each comprise at least two openings 158 as part of the output channels 156. At least one of the output channels 156 may comprise at least one modulation element 164 for modulating the respective light beam 116. The modulation element 164 may be disposed in an intermediate space between the inner housing 160 and the outer housing 162, specifically between the respective openings 158 of the inner housing 160 and the outer housing 162. The modulation element 164 may be attached to the inner housing 160.

[0116] The electronic circuit 136 may be at least partially surrounded by the outer housing 162. Specifically, at least the printed circuit board 138 may be surrounded by the outer housing 162. The housing 150 may include at least one base element 166. The inner housing 160 and the outer housing 162 may be mounted directly or indirectly on the base element 166. Specifically, the outer housing 162 may be mounted directly on the base element 166. The electronic circuit 136 may be housed in the outer housing 162 behind the inner housing 160. The light emitting element 128 may be attached to the electronic circuit 136. The light emitting element 128 may protrude from the electronic circuit 136 into the inner housing 160. The inner housing 160 may be mounted on the electronic circuit 136, specifically on the printed circuit board 138. The printed circuit board 138 may be mounted on the base element 166. The base element 166 may include a number of legs 168 that specifically reduce vibration.

[0117] At least one optical element 170 may be disposed inside the outer housing 162, specifically in at least one of the openings 158 of the inner housing 160. Specifically, the optical element 170 may comprise a lens 172 housed in each of the openings 158 of the inner housing 160. The lens 172 may specifically be a focusing lens 174. The optical element 170 may further comprise at least one of an aperture, an optical filter, a dispersive element, a diffractive element, an active element such as a spatial light modulator, and a mirror (not shown). The optical element 170 may be comprised by at least one of the output channels 156. The optical element 170 may in particular be movable. More specifically, the optical element 170 may be movable into at least one of the output channels 156 and out of at least one of the output channels 156, respectively. Thus, the optical element 170 may be used to independently control each of the output channels 156.

[0118] The spectral light source 112 may comprise at least one actuator 176. The actuator 176 may comprise a modulation element 164. The modulation element 164 may specifically be or may comprise at least one chopper wheel 178. The actuator 176 may comprise at least one stepper motor 180. The stepper motor 180 may be configured to rotate the chopper wheel 178 at a predetermined frequency. This may be used to modulate the light beam 116 separated from the spectral light source 112 via the output channel 156. The chopper wheel 178 may comprise at least one opaque sector 182 configured to block all incident light intensity. The chopper wheel 178 may be arranged to periodically move the at least one opaque sector 182 into at least one of the output channels 156 of the spectral light source 112 during the rotation of the chopper wheel 178. Thus, the amplitude of the at least one light beam 116 separated via the respective output channel 156 may be modulated at a corresponding frequency. The actuator 176 may further be or include at least one shutter, not shown.

[0119] At least one of the output channels 156 may include a fiber optic connector 184. The fiber optic connector 184 may be attached to an exterior surface of the housing 150, specifically, to an exterior surface of the outer housing 162, more specifically, to the exterior surface of the outer housing 162 at at least one of the openings 158 in the outer housing 162. Specifically, an adapter 186 may be attached to the opening 158 in the outer housing 162. The adapter 186 may include threads. The fiber optic connector 184 may be configured to be screwed into the threads of the adapter 186.

[0120] The spectral light source 112 may comprise at least one cooling device 188. The cooling device 188 may be or may comprise at least one fan 190. The housing 150 may comprise at least one top cover 192. The fan 190 may be attached to the top cover 192. The cooling device may further be or may comprise at least one heat sink, not shown. The light-emitting elements 128, the electronic circuitry 136 and the cooling device 188 may be spatially separated. This facilitates in particular shielding the light-emitting elements 128 and / or the electronic circuitry 136 from environmental influences, for example dirt or dust, which may be particularly important for explosion protection.

[0121] 3 shows an embodiment of a schematic circuit diagram of a controller 146 for controlling the power applied to the light-emitting element 128 of the spectral light source 112. The controller 146 can be configured to perform a soft start and / or a soft stop of the light-emitting element 128. Specifically, a voltage ramp can be applied to the light-emitting element 128 over time when switching the light-emitting element 128 on and off, respectively. The voltage ramp can be applied for a time interval that varies from 1 second to 60 seconds, preferably from 2 seconds to 30 seconds, and more preferably from 3 seconds to 10 seconds. The controller 146 can include at least one step-down regulator 194. The step-down regulator can include at least one input connection 196 for receiving power, specifically an input voltage, from the power source 152. The step-down regulator 194 can include at least one output connection 198 for outputting an output voltage. The step-down regulator 194 can include at least one feedback connection 200. The controller 146 can include at least one resistor network 202. The resistive network 202 may include at least one resistor 204. In particular, the resistive network 202 may include three resistors 204 and wires 206 and / or traces 208 for at least partially interconnecting the three resistors 204. At least one of the resistors 200 may be grounded. The ground potential, or simply ground, is indicated in FIG. 3 by reference numeral 210. The resistive network 202 may form a voltage divider. The controller may include at least one digital-to-analog converter 212. The digital-to-analog converter 212 may be grounded. The digital-to-analog converter 212 may be configured to control the modification of the input voltage by the buck regulator 194 by using the feedback connection 200. The controller 146 may include at least one shunt 214. The shunt 214 may be configured for current sensing and / or voltage sensing. Specifically, the shunt 214 may include a shunt resistor 216 disposed in parallel with a shunt voltmeter 218 .

[0122] The power source 152 can provide an input voltage, specifically a DC input voltage, to the step-down regulator 194 via an input connection 196. The step-down regulator 194 can step down the input voltage to an output voltage that is provided to a shunt 214 and a resistive network 202 via an output connection 198. The output voltage can be digitally controlled by using a digital-to-analog converter 212. The digital-to-analog converter 212 can convert a predetermined digital signal, for example from a measurement computer, to an analog voltage. The digital-to-analog converter 212 can be connected to the resistive network 202, which can further be connected to a feedback connection 200 of the step-down regulator 194. Thus, the digitally controlled analog voltage of the digital-to-analog converter 212 can be added to the feedback connection 200 of the step-down regulator 194. An output current corresponding to the output voltage can be further measured by measuring the voltage drop across the shunt resistor 216 and using Ohm's law before the output voltage and output current can be applied to the light emitting element 128. In particular, the current loss on the shunt voltmeter 218 may be negligible, for example, due to the use of a low resistance shunt resistor 216. The output voltage and the output current can finally be multiplied to calculate the power applied to the light emitting element 126.

[0123] 4A-4E show experimental results of stability measurements for one embodiment of the spectral light source 112. FIG. 4A shows a short-term stability measurement of the spectral light source 112 over a time t of about 100 seconds. The optical power output P optcan be measured by using a Thorlabs PM400 power meter equipped with an S122C germanium power meter head. The measurements yielded an average optical power output of 4.573 mW with a standard deviation of 2.3 μW. Therefore, the optical power output can be considered very stable in the short term. Figures 4B-4E all show long-term stability measurements over 8000 seconds. As Figure 4B shows, for the first approximately 4000 seconds, the optical power output actually increases slightly. After the initial increase, the optical power output remains very stable at approximately 4.580 mW. At the same time, as Figure 4C shows, the power P applied to the light-emitting element 128 by the electronic circuit 136 el remains constant at about 12 W. As indicated above, the power can be derived from the sensor measurements. In particular, the voltage applied to the light-emitting element 128 can be controlled by using the controller 146, more particularly by using the digital-to-analog converter 212. In this regard, reference can be made to the schematic circuit diagram shown in FIG. 3 and the corresponding parts of the description. As further indicated in this context, the current applied to the light-emitting element 128 can be measured by using the shunt 214. FIGS. 4D and 4E show further sensor data. FIG. 4D shows that the resistance R of the light-emitting element 128 always remains about 14.46 Ω in a long-term measurement of more than 8000 seconds. FIG. 4E shows that the temperature T rises up to about 37° C. during the first about 6000 seconds and then remains at this temperature in a very stable manner. Such measurements can form the basis for generating a temperature calibration table for the spectral light source 112.

[0124] 5 shows a flow chart of one embodiment of a method of operation of the spectroscopic measurement system 110. The method of operation of the spectroscopic measurement system 110 includes the following measurement steps: a) applying power, in particular at least one voltage, to the light-emitting elements 128 of the spectral light source 112 by using an electronic circuit 136 (denoted by reference numeral 220); b) illuminating by using light emitting element 128 (denoted by reference numeral 222); c) isolating at least one light beam 116 from the spectral light source 112 by using at least one output channel of the at least two output channels 156 while independently controlling each one of the output channels 156 (denoted by reference numeral 224); d) illuminating at least one measurement object 126 with the light beam 116 (denoted by reference numeral 226); e) detecting the light beam 116 by using the detector 114 of the spectroscopic measurement system 110 (denoted by reference numeral 228) and generating at least one corresponding detector signal; f) reading out the detector signal by using the readout electronics 118 of the spectroscopic measurement system 110 (denoted by reference numeral 230); g) determining at least one item of information based on the detector signal by using the evaluation device 120 of the spectroscopic measurement system 110 (reference numeral 232); Includes.

[0125] The method steps a) to g) can be performed in a given order. However, it should be noted that a different order is also possible. Furthermore, one or more method steps may be performed once or repeatedly. Furthermore, two or more method steps may be performed simultaneously or with overlapping time. The method may also include further method steps not listed. In step f), the detector signal may be further amplified by using a lock-in amplifier 127.

[0126] In step c), the controlling may include turning on and off at least one of the output channels 156. The controlling may include modulating the light beam 116 in at least one of the output channels 156, in particular modulating at least one of the amplitude of the light beam 116, the frequency of the light beam 116, and the duty cycle of the light beam 116. The controlling may include modulating the amplitude of the light beam 116 in at least one of the output channels 156 with a frequency between 0 Hz and 1000 Hz, preferably between 0.5 Hz and 1000 Hz, more preferably between 1 Hz and 500 Hz, and even more preferably between 8 Hz and 128 Hz.

[0127] In step c), at least two light beams 116 can be separated from the spectral light source 112. Each light beam 116 may be separated via a different output channel 156 of the spectral light source 112. In step d), the measurement object 126 can be illuminated by at least one of the at least two light beams 116. At least one light beam 116 of the at least two light beams 116 can be used as a reference in determining the information item in step g). Independently controlling the output channels 156 in step c) can include modulating at least one light beam 116 in the respective output channel 156 differently from at least one remaining light beam 116 in the at least one remaining output channel 156.

[0128] The method may be computer-implemented. With reference to the computer-implemented aspects of the present invention, one or more of the method steps, or even all of the method steps, of the method according to one or more of the embodiments disclosed herein may be performed by using a computer or a computer network. Thus, in general, any of the method steps involving providing and / or manipulating data may be performed by using a computer or a computer network. In general, these method steps may include any method steps, except for those that typically require manual work. [Explanation of symbols]

[0129] 110 Spectroscopic Measurement System 112 Spectral light source 114 Detector 116 Light Beam 118 Readout electronic devices 120 Evaluation device 122 Measurement light beam 124 Reference Light Beam 126 Measurement Object 127 Lock-in Amplifier 128 Light Emitting Elements 130 Incandescent lamp 132 Halogen incandescent bulb 134 Sockets 136 Electronic circuits 138 Printed Circuit Board 140 Sensors 142 Interface 144 USB ports 146 Controller 148 Microcontrollers 150 Housing 152 Power supply 154 Cable Feedthrough 156 output channels 158 Opening 160 Inner housing 162 Outer housing 164 Modulation Elements 166 Base Elements 168 legs 170 Optical elements 172 Lens 174 Condenser Lens 176 Actuator 178 Chopper Wheel 180 Stepping motor 182 Opaque Sector 184 Optical Connector 186 Adapter 188 Cooling device 190 Fans 192 Top cover 194 Buck Regulator 196 Input Connection 198 Output Connection 200 Feedback Connection 202 Resistor Network 204 Resistor 206 Wire 208 Trace 210 Grounding 212 Digital-to-Analog Converter (DAC) 214 Shunt 216 Shunt Resistor 218 Shunt voltmeter 220 Method step a) 222 Method step b) 224 Method step c) 226 Method step d) 228 Method step e) 230 Method step f) 232 Method step g)

Claims

1. - at least one light-emitting element (128); - at least one electronic circuit (136) configured to apply power to the light-emitting element (128); - at least one housing (150), the housing (150) surrounding the light-emitting element (128) at least partially; - at least two output channels (156) passing through the housing (150), each of the output channels (156) being configured to separate at least one light beam (116) from a spectral light source (112); comprising The spectral light source (112) is configured to independently control each of the output channels (156), the housing (150) comprises an inner housing (160) surrounding the light-emitting element (128) at least partially, the housing (150) further comprises an outer housing (162), the outer housing (162) surrounding the inner housing (160) at least partially, the inner housing (160) and the outer housing (162) each comprise at least two openings (158) as part of the output channels (156), the housing (150) comprises at least one base element (166), the inner housing (160) and the outer housing (162) are placed directly or indirectly on the base element (166), the electronic circuit (136) is housed under the inner housing (160) within the outer housing (162), the light-emitting element (128) is attached to the electronic circuit (136), and the light-emitting element (128) protrudes from the electronic circuit (136) into the inner housing (160). Spectral light source (112).

2. The spectral light source (112) according to claim 1, wherein the light-emitting element (128) comprises at least one incandescent lamp (130).

3. The spectroscopic light source (112) according to claim 1, wherein the spectroscopic light source (112) is configured to turn on and off at least one of the output channels (156).

4. The spectroscopic light source (112) according to claim 1, wherein the spectroscopic light source (112) is configured to modulate the light beam (116) in at least one of the output channels (156).

5. The spectroscopic light source (112) according to claim 1, wherein the spectroscopic light source (112) is configured to independently modulate each of the light beams of the output channels (156).

6. The spectroscopic light source (112) according to claim 4, wherein at least one optical element (170) is disposed inside the outer housing (162), and the optical element (170) includes lenses (172) respectively received in the openings (158) of the inner housing (160).

7. The spectroscopic light source (112) according to claim 1, further comprising at least one actuator (176), the actuator (176) including at least one modulation element (164), and the modulation element (164) including at least one of a shutter and a chopper wheel (178).

8. The spectroscopic light source (112) according to claim 1, wherein at least one of the output channels (156) includes an optical fiber connector (184).

9. The spectroscopic light source (112) according to claim 1, wherein the electronic circuit (136) includes at least one interface (142).

10. The spectroscopic light source (112) according to claim 1, wherein the electronic circuit (136) includes at least one controller (146) configured to control at least one of the power applied to the light emitting element (128) or at least one of the output channels (156).

11. The spectral light source (112) according to claim 10, wherein the controller (146) is configured to perform soft start and / or soft stop of the light emitting element (128).

12. - at least one spectral light source (112) according to any one of claims 1 to 11; - at least one detector (114) configured to detect at least one light beam (116) separated from the spectral light source (112) and further configured to generate at least one corresponding detector signal; - at least one readout electronics (118) configured to read out the detector signal; - at least one evaluation device (120) configured to determine at least one information item based on the detector signal, A spectral measurement system (110) comprising.

13. A method of operating a spectral measurement system (110) according to claim 12, the method comprising a) applying power to a light emitting element (128) of a spectral light source (112) by using an electronic circuit (136); b) emitting light by using the light emitting element (128); c) separating at least one light beam (116) from the spectral light source (112) by using at least one of at least two output channels (156) while independently controlling each of the output channels (156); d) irradiating at least one measurement object (126) with the light beam (116); e) detecting the light beam (116) by using a detector (114) of the spectral measurement system (110) and generating at least one corresponding detector signal; f) reading out the detector signal by using readout electronics (118) of the spectral measurement system (110); g) determining at least one information item based on the detector signal by using an evaluation device (120) of the spectroscopic measurement system (110); A method comprising:

14. In step c), at least two light beams (116) are separated from the spectroscopic light source (112), each light beam (116) being separated via a different output channel (156) of the spectroscopic light source (112), and in step d), the object under measurement (126) is irradiated by at least one of the at least two light beams (116), and in step c), independently controlling the output channels (156) comprises modulating at least one light beam (116) in each of the respective output channels (156) to be different from at least one remaining light beam (116) in at least one remaining output channel (156). The method according to claim 13.

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