TIR-free spectrometry with transmission gratings

Abstract

The present disclosure relates to a spectrometer device (110) for obtaining at least one item of spectral information on at least one object (112) by spectroscopic measurement, comprising - a detector (138) configured for detecting detection light (122) from the at least one object (112), the detector (138) comprising a plurality of photosensitive elements (140), - a transmission grating (120), wherein the transmission grating (120) comprises a grating structure (124) and a substrate body (126), wherein the grating structure (124) is configured such that the plurality of photosensitive elements (140) are exposed to a differing spectral range of the detection light (122), wherein the substrate body (126) comprises a first surface (128) and a second surface (130), wherein the first surface (128) is opposite of the second surface (130), wherein the first surface (128) is a straight line in a cross-sectional plane, wherein the second surface (130) is a straight line in the cross-sectional plane, wherein the grating structure (124) is arranged on the first surface (128), - at least one focusing optical element (136) configured to receive detection light (122) from the transmission grating (120), wherein a focus point of the focusing optical element (136) coincides with the detector (138), wherein the detection light (122) is propagating from the transmission grating (120) through the focusing optical element (136) onto the detector (138), wherein a normal of the first surface (132) and a normal of the second surface (134) that are tilted in respect to each other, wherein the normal of the first surface (132) and the normal of the second surface (134) lie in the cross-sectional plane.

Description

[0001] 240380W001

[0002] TIR-Free Spectrometry with Transmission Gratings

[0003] Technical Field

[0004] The invention relates to a spectrometer device, a mobile device and a method for obtaining spectroscopic information on at least one object by using a spectrometer device.

[0005] The methods and devices according to the present invention specifically may be employed for example in various areas of daily life, security technology, gaming, traffic technology, production technology, photography such as digital photography or video photography for arts, documentation or technical purposes, safety technology, information technology, agriculture, crop protection, maintenance, cosmetics, medical technology or in the sciences. However, other applications are also possible.

[0006] Background art

[0007] In a spectrometer device comprising a transmission grating, usually, the +1stor -1stdiffraction order of detection light is directed onto the detector. Further diffraction orders may be unwanted since they can cause stray light or imaging distortions in the spectrometer device.

[0008] However, reflective diffraction orders that are totally internally reflected in the transmission grating and are diffracted a second time on the grating surface, may show the identical angle distribution as nominal light. The spatial light distribution of the totally internally reflected light typically overlaps the nominal light path.

[0009] EP 0 602 992 B1 discloses a dispersive optical element having a predetermined dynamic range of resolving power comprising: a prism having first and second surfaces defining a prism angle and a base opposite the prism angle; and grating means adjacent to one surface of the prism, the grating means being adapted to disperse radiation having multiple spectral bands; characterized in that the resolving power of the dispersive optical element.

[0010] US 6 485 625 B1 discloses an integrated instrument for the high-capacity electrophoretic analysis of biopolymer samples. It comprises a specialized high-voltage, electrophoretic module in which the migration lanes are formed between a bottom plate and a plurality of etched grooves in a top plate, the module permitting concurrent separation of 80 or more separate samples. In 240380W001

[0011] - 2 - thermal contact with the bottom plate is a thermal control module incorporating a plurality of Pel- tier heat transfer devices for the control of temperature and gradients in the electrophoretic medium.

[0012] US 2018 / 080826 A1 discloses an imaging spectrometer and a method. In one example, the imaging spectrometer includes foreoptics positioned to receive electromagnetic radiation from a scene, a diffraction grating positioned to receive the electromagnetic radiation from the foreoptics and configured to disperse the electromagnetic radiation into a plurality of spectral bands, each spectral band corresponding to a diffraction grating order of the diffraction grating, and a single-band focal plane array configured to simultaneously receive from the diffraction grating overlapping spectra corresponding to at least two diffraction grating orders.

[0013] YANG CHUAN ET AL: "Demonstration of a PDMS based hybrid grating and Fresnel lens (G- Fresnel) device", OPTICS EXPRESS, vol. 18, no. 23, 26 October 2010 (2010-10-26), page 2352 describes a hybrid device termed G-Fresnel (i.e. , grating and Fresnel). It fuses the functions of a grating and a Fresnel lens into a single device. They have fabricated the G-Fresnel device by using polydimethylsiloxane (PDMS) based soft lithography. Three-dimensional surface profilometry has been performed to examine the device quality. They have also conducted optical characterizations to confirm its dual focusing and dispersing properties. The G-Fresnel can be useful for the development of miniature optical spectrometers as well as emerging optofluidic applications.

[0014] Problem to be solved

[0015] It is therefore desirable to provide a spectrometer device, a mobile device and a method for obtaining spectroscopic information on at least one object by using a spectrometer device, which at least partially address the above-mentioned technical challenges and at least substantially avoid the disadvantages of known methods and devices.

[0016] In particular, it is an object of the present invention to provide a spectrometer device, a mobile device and a method for obtaining spectroscopic information on at least one object by using a spectrometer device that enable an improved separation of non-totally reflected and totally reflected light traversing through a transmission grating in order to improve the spectroscopic quality.

[0017] Summary 240380W001

[0018] - 3 -

[0019] This problem is addressed by a spectrometer device, a mobile device and a method for obtaining spectroscopic information on at least one object by using a spectrometer device with the features of the independent claims. Advantageous embodiments which might be realized in an isolated fashion or in any arbitrary combinations are listed in the dependent claims as well as throughout the specification.

[0020] In a first aspect, a spectrometer device for obtaining at least one item of spectral information on at least one object by spectroscopic measurement is disclosed. For this aspect, reference may be made to any further aspect, particularly any definition, Embodiment or claim given in the context of any further aspect.

[0021] The term “spectrometer device” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an optical device configured for acquiring at least one item of spectral information on at least one object. Specifically, the at least one item of spectral information may refer to at least one optical property or optically measurable property which is determined as a function of a wavelength, for one or more different wavelengths. More specifically, the optical property or optically measurable property, as well as the at least one item of spectral information, may relate to at least one property characterizing at least one of a transmission, an absorption, a reflection and an emission of the at least one object, either by itself or after illumination with external light. The at least one optical property may be determined for one or more wavelengths. The spectrometer device specifically may form an apparatus which is capable of recording a signal intensity with respect to the corresponding wavelength of a spectrum or a partition thereof, such as a wavelength interval, wherein the signal intensity may, specifically, be provided as an electrical signal which may be used for further evaluation.

[0022] The term “spectral information”, also referred to as “spectroscopic information” or as “an item of spectral information”, as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an item of information, e.g. on at least one object and / or radiation emitted by at least one object, characterizing at least one optical property of the object, more specifically at least one item of information characterizing, e.g. qualifying and / or quantifying, at least one of a transmission, an absorption, a reflection and an emission of the at least one object. As an example, the at least one item of spectral information may comprise at least one intensity information, e.g. information on an intensity of light being at least one of transmitted, absorbed, reflected or emitted by the object, e.g. as a 240380W001

[0023] - 4 - function of a wavelength or wavelength sub-range over one or more wavelengths, e.g. over a range of wavelengths. Specifically, the intensity information may correspond to or be derived from the signal intensity, specifically the electrical signal, recorded by the spectrometer device with respect to a wavelength or a range of wavelengths of the spectrum.

[0024] The “object” may, generally, be an arbitrary body, chosen from a living object and a non-living object. Thus, as an example, the at least one object may comprise one or more articles and / or one or more parts of an article, wherein the at least one article or the at least one part thereof may comprise at least one component which may provide a spectrum suitable for investigations. Additionally or alternatively, the object may be or may comprise one or more living beings and / or one or more parts thereof, such as one or more body parts of a human being, e.g. a user, and / or an animal.

[0025] The spectrometer device comprises a detector configured for detecting detection light from the at least one object, the detector comprising a plurality of photosensitive elements, a transmission grating, wherein the transmission grating comprises a grating structure and a substrate body, wherein the grating structure is configured such that the plurality of photosensitive elements are exposed to a differing spectral range of the detection light, wherein the substrate body comprises a first surface and a second surface, wherein the first surface is opposite of the second surface, wherein the first surface is a straight line in a cross-sectional plane, wherein the second surface is a straight line in the cross-sectional plane, wherein the grating structure is arranged on the first surface,

[0026] - wherein the spectrometer device comprises at least one focusing optical element configured to receive detection light from the transmission grating, wherein a focus point of the focusing optical element coincides with the detector, wherein the detection light is propagating from the transmission grating through the focusing optical element onto the detector wherein a normal of the first surface and a normal of the second surface that are tilted in respect to each other, wherein the normal of the first surface and the normal of the second surface lie in the cross-sectional plane.

[0027] The verb “to detect” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to the process of at least 240380W001

[0028] - 5 - one of determining, measuring and monitoring at least one parameter, qualitatively and / or quantitatively, such as at least one of a physical parameter, a chemical parameter and a biological parameter. Specifically, the physical parameter may be or may comprise an electrical parameter. Consequently, the term “photosensitive detector”, or “detector” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an arbitrary device configured for detecting, i.e. for at least one of determining, measuring and monitoring at least one parameter, qualitatively and / or quantitatively, such as at least one of a physical parameter, a chemical parameter and a biological parameter. The at least one detector may be configured for generating at least one detector signal, more specifically at least one electrical detector signal, such as an analogue and / or a digital detector signal, the detector signal providing information on the at least one parameter measured by the detector. The detector signal may directly or indirectly be provided by the at least one detector to the evaluation unit, such that the at least one detector and the evaluation unit may be directly or indirectly connected. The detector signals may be used as a “raw” detector signal and / or may be processed or preprocessed before further used, e.g. by filtering and the like. Thus, the at least one detector may comprise at least one processing device and / or at least one preprocessing device, such as at least one of an amplifier, an analogue / digital converter, an electrical filter and a Fourier transformation.

[0029] The at least one detector may be configured for detecting light, specifically detection light, propagating from the object to the spectrometer device or more specifically to the at least one detector of the spectrometer device. The at least one detector may be configured for determining at least one optical parameter, such as an intensity and / or a power of light by which at least one sensitive area of the detector is irradiated. More specifically, the at least one detector may comprise at least one photosensitive element and / or at least one optical sensor, such as at least one of a photodiode, a photocell, a photosensitive resistor, a phototransistor, a thermophile sensor, a photoacoustic sensor, a pyroelectric sensor, a photomultiplier and a bolometer. The at least one detector, thus, may be configured for generating at least one detector signal, more specifically at least one electrical detector signal, in the above-mentioned sense, providing information on at least one optical parameter, such as the power and / or intensity of light by which the detector or a sensitive area of the detector is illuminated. The at least one detector may be a Lead Sulfide (PbS) detector.

[0030] The detector may comprise a plurality of photosensitive elements, wherein each of the photosensitive elements may be configured for generating at least one detector signal for deriving the spectral information. The plurality of photosensitive elements may be arranged in an array. The 240380W001

[0031] - 6 - term “array” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a series of optical sensors which may, preferably, be arranged in a single line as a one-dimensional matrix along the length of the length variable filter or in more than one line, especially in two, three, or four parallel lines, in form of a two-dimensional matrix, in particular, in order to receive most of the intensity of the incident light as possible. Thus, a number N of photosensitive elements in one direction may be higher compared to a number M of photosensitive elements in a further direction such that the one-dimensional 1 x N matrix or a rectangular two-dimensional M x N matrix may be obtained, wherein M < 10 and N > 10, preferably N > 20, more preferred N > 50. In addition, the matrixes may also be placed in a staggered arrangement.

[0032] The plurality of photosensitive elements may be sensitive to differing, particularly not overlapping, wavelength intervals. Particularly consequently, a first photosensitive element may detect light within a first wavelength range and a second photosensitive element may detect light within a second wavelength range, wherein the first and the second wavelength range are different from each other, particularly in a manner that the wavelength ranges do not overlap. There may be a third photosensitive element having a further different, particularly not overlapping, wavelength range, and so on. The detector may comprise at least one of: at least one of photosensitive element; at least one readout circuitry; at least one bias voltage.

[0033] As further used herein, the term “light” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to electromagnetic radiation in one or more of the infrared, the visible and the ultraviolet spectral range. Herein, the term “ultraviolet spectral range”, generally, refers to electromagnetic radiation having a wavelength of 1 nm to 380 nm, preferably of 100 nm to 380 nm. Further, in partial accordance with standard ISO-21348 in a valid version at the date of this document, the term “visible spec-tral range”, generally, refers to a spectral range of 380 nm to 760 nm. The term “infrared spectral range” (IR) generally refers to electromagnetic radiation of 760 nm to 1000 pm, wherein the range of 760 nm to 1.5 pm is usually denominated as “near infrared spectral range” (NIR) while the range from 1.5 p to 15 pm is denoted as “mid infrared spectral range” (MidlR) and the range from 15 pm to 1000 pm as “far infrared spectral range” (FIR). Preferably, light used for the typical purposes of the present invention is light in the infrared (IR) spectral range, more preferred, in the near infrared (NIR) and / or the mid infrared spectral range (MidlR), especially the light having a wavelength of 1 pm to 5 pm, preferably of 1 pm to 3 pm. This is due to the fact that many material properties or properties on the chemical constitution of many objects may be 240380W001

[0034] - 7 - derived from the near infrared spectral range. It shall be noted, however, that spectroscopy in other spectral ranges is also feasible and within the scope of the present invention.

[0035] As further used herein, the term “detection light” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to light that is generated by the object, particularly generated in an interaction of illumination light generated by a light emitting element comprised by the spectrometer device with the object.

[0036] The illumination light may interact with the object by scattering, reflecting and / or transmitting. At least a portion of the illumination light may be transmitted and / or absorbed by the object in a manner that it is not detected by the at least one detector.

[0037] As further used herein, the term “transmission grating” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an optical device used to disperse light into its component wavelengths. The dispersion is based on the principles of diffraction. The transmission grating may be used to spatially separate incident light of differing wavelengths. The spatially separated light may be guided onto a detector in a manner that light of differing wavelengths impinges on differing photosensitive elements. The “first surface” and / or the “second surface” may be outer surfaces of the transmission grating. The first surface and the second surface each may be planar surfaces. At least one of: the first surface; the second surface may be configured for receiving detection light incident on the transmission grating.

[0038] The transmission grating may comprise a “substrate body”. The substrate body of a transmission grating may be the base material on which the grating structure is etched or deposited. Typically, a substrate may be made of at least one transparent material. A material of the substrate body may be or may comprise at least one of: silicon; fused silica; an optical glass; a synthetic material and / or plastic material; Calciumfluorid; Zinc selenide. The substrate may have mechanical stability and / or durability to maintain the integrity of the grating structure. The refractive index of the substrate body may be below 1.43, preferably below 1.35, more preferably 1.3; or above 1.45, preferably above 2.0, more preferably 3.4.

[0039] The transmission grating may comprise a “grating structure”. The grating structure of a transmission grating may consist of a series of finely spaced lines or grooves etched or deposited onto the substrate body. Said lines or grooves act as obstacles that cause incoming light to diffract and interfere and, thereby, to create a spectrum of separated wavelengths. The spacing 240380W001

[0040] - 8 - between the lines, known as the grating period, may determines the angles at which different wavelengths are diffracted. A material of the grating structure may be or may comprise at least one of: silicon; fused silica; an optical glass; a synthetic material and / or plastic material; Calci- umfluorid; Zinc selenide. The grooves formed by the grating structure may expand in a direction that is parallel to a vertex-base axis defined by the transmission grating, wherein the vertexbase axis runs from the narrow end to the wide end of the transmission grating.

[0041] As already indicated, a normal of the first surface and a normal of the second surface that are tilted in respect to each other, wherein the normal of the first surface and the normal of the second surface lie in the cross-sectional plane. The term “tilted” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to two objects not being aligned and / or being oriented in the same direction, such as by being parallel. Two vectors, specifically the normal of the first surface and the normal of the second surface, may be tilted, particularly relative to each other, when an angle is formed between the two vectors. For the normal of the first surface and the normal of the second surface being tilted in respect to each other, an angle between the normal of the first surface and the normal of the second surface may be between 0.5° and 10°, preferably 2° and 8°, more preferably 5° and 7°.

[0042] The substrate body may have a wedged shaped portion in the cross-sectional plane, wherein the first surface and the second surface are convergent surfaces of the wedged shaped portion. The term “wedge shaped” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a form of an element that is narrow at an end of the element and wider at a further end of the element. Typically, the element may become gradually narrower as is extends in a specific direction. A wedge shaped element may comprise two converging sides. The converging sides may meet at the narrow end of the element. Alternatively, the converging sides may remain distance from each other at the narrow end of the element.

[0043] The substrate body may have at least one further wedged shaped portion in the cross-sectional plane, wherein the further wedged shaped portion may be different from the wedged shaped portion. The substrate body may comprise at least one further first surface and at least one further second surface. The at least one further first surface may be opposite of the at least one further second surface, wherein the at least one further first surface may be a straight line in the cross-sectional plane, wherein the at least one further second surface is a straight line in the cross-sectional plane. The at least one further first surface and the at least one further second 240380W001

[0044] - 9 - surface are convergent surfaces of the at least one further wedged shaped portion. The wedged shaped portion and the at least one further wedged shaped portion may be concentrically arranged around a center axis, wherein the center axis lies in the cross-sectional plane. The wedged shape portion and the at least one further wedged shaped portion of the transmission grating may be part of a Fresnel lens.

[0045] The term "concentrically arranged around a center axis" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a structure comprising a plurality of elements, wherein the elements are arranged in rings that share the same center axis. Each element may be arranged around this central point, whereby each element may form a ring.

[0046] The transmission grating may comprise a plurality of rings. The wedged shape portion and the further wedged shaped portion may by assigned to differing rings. For the wedged shaped portion and the at least one further wedged shaped portion to be concentrically arranged around the center axis, the plurality of rings may be concentrically arranged around the center axis.

[0047] The term “Fresnel lens” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a specific optical lens developed by A. J. Fresnel. The refractive surface of a Fresnel lens may comprise steps, such as saw teeth, particularly in order to reduce the thickness of the Fresnel lens, particularly when compared to a thickness of an optical lens not being a Fresnel lens. The saw teeth may be formed by the wedged shaped portion and the at least one further wedged shaped portion of the transmission grating. A Fresnel lens may be composed of prismatic sections consisting of concentric circular rings. The concentric circular rings may be formed by the wedged shaped portion and the at least one further wedged shaped portion of the transmission grating.

[0048] A height between the first surface and the second surface may be below 1 mm, preferably o below 0.47 mm for a refractive index of the substrate body of 1.3; or o below 0.14 mm for a refractive index of the substrate body of 3.4.

[0049] The term “height” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a distance measurement along 240380W001

[0050] - 10 - an axis defined by an object, wherein said axis goes from the top to the bottom of the object. The height h may be calcutated by the following formula h = L * sin(0), wherein L is the length of the wedge's base, specifically the first surface or the second surface, and 0 is the angle of inclination of the wedge.

[0051] The spectrometer device is configured such that only a specific diffraction order, particularly the +1st diffraction order, of the light transmitted through the transmission grating is directed onto the detector. The specific diffraction order of the light transmitted through the transmission grating may be related to light that is totally reflected within the transmission grating. A direction of the light transmitted through the transmission grating having a specific diffraction order and being totally reflected within the transmission grating may differ from a direction of the light transmitted through the transmission grating having the same specific diffraction order and not being totally reflected within the transmission grating. Consequently, the direction of the light may dependent on the fact if the light is totally reflected within the transmission grating or if the light is not totally reflected within the transmission grating. The further diffraction orders of light transmitted through the transmission grating may not impinge the detector.

[0052] For the spectrometer device to be configured such that only the specific diffraction order of the light transmitted through the transmission grating is directed onto the detector, the spectrometer comprises at least one aperture configured for blocking at least one diffraction order of light transmitted through the transmission grating that differs from only the specific diffraction order. The blocked diffraction order of the light transmitted through the transmission grating may be related to light that is totally reflected within the transmission grating and to light that is not totally reflected within the transmission grating. The term “blocking” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to attenuating the intensity of light to a certain degree, such as attenuating the light to at least 80%, 90%, 95% or even 100 %.

[0053] The at least one aperture configured for blocking the at least one diffraction order may be arranged between the transmission grating and the at least one focusing optical element. The at least one aperture configured for blocking the at least one diffraction order may be arranged in the light path of the detection light. Consequently, detection light transmitted through the trans- 240380W001

[0054] - 11 - mission grating may impinge the at least one aperture configured for blocking at least one diffraction order and may then be transmitted through the aperture configured for blocking the at least one diffraction order and then further onto the at least one focusing optical element.

[0055] The grating structure may define a planar grating surface, wherein the detector may define a planar detector surface, wherein, for the spectrometer device being configured such that only the specific diffraction order of the light transmitted through the transmission grating is directed onto the detector, the normal of the surface of the transmission grating from which the detection light emerges and a normal of the planar detector surface may be tilted in respect to each other. The surface of the transmission grating from which the detection light emerges may be the surface that is facing the detector. The surface of the transmission grating from which the detection light emerges may be the surface from which the transmitted detection light leaves the transmission grating and propagates to the detector, particularly without propagating through the transmission grating. For the normal of the normal of the surface of the transmission grating from which the detection light emerges and the normal of the planar detector surface to be tilted in respect to each other, an angle between the normal of the surface of the transmission grating from which the detection light emerges and the normal of the planar detector surface may be between 1 ° and 45°, more preferably 5° and 30°.

[0056] The term “focusing optical element” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an optical element used to converge light rays to a specific point, preferably onto the detector. The focus point of the focusing optical element may be a principal focus point. The focusing optical element may be selected from at least one of: an optical lens; an optical mirror.

[0057] The spectrometer device may comprise at least one sample interface, wherein the sample interface may define a measurement surface, wherein the measurement surface may be configured for defining a measurement pose of the at least one object.

[0058] The term “sample interface” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an arbitrary surface, such as measurement surface, at which an object is intended to interact with an optical measurement system, such as the spectrometer device. The measurement surface may be a measurement plane. For interacting with the object, the spectrometer device may emit the illumination light, particularly in a manner that the object generates the detection light. In addition, the 240380W001

[0059] - 12 - spectrometer may receive the detection light. Particularly to allow the interaction with the object as intended, the sample interface may define a measurement pose of the object. When the object assumes the measurement pose, particularly as defined by the sample interface, at least one of: receiving the illumination light by the object and, thereby, generating the detection light is performed in a manner as intended, such as that when the object assumes the measurement pose, the signal-to-noise ratio of the spectrometer device is maximized.

[0060] The term “measurement pose” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a relative position and / or orientation of the object relative to the sample interface, which is intended to be assumed during the spectral measurement, particularly to allow an interaction between the spectrometer device and the object as intended, such as intended by the setup and / or arrangement of the components of the spectrometer device.

[0061] The spectrometer device may comprise at least one aperture configured to receive detection light from the at least one sample interface, wherein the detection light may be propagating through the aperture onto the transmission grating.

[0062] The term “aperture” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an opening used to control the amount of light entering the optical system. Thereby, the resolution and / or the sensitivity of the spectrometer device may be increased, particularly by reducing stray light, defining the divergence of the incident light and the focusing characteristics of the spectrometer device. The aperture may be a slit. The aperture may be the entrance slit of the spectrometer device.

[0063] The spectrometer device may comprise at least one collimating lens, wherein a focus point of the collimating lens coincides with the aperture, wherein the detection light is propagating from the aperture through the collimating lens onto the transmission grating.

[0064] The term “collimating lens” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an optical component used to transform divergent or convergent light beams into a parallel light beam. The “focus point”, also known as the focal point, may be the principal focus point. The principal focus point 240380W001

[0065] - 13 - may be the point on an axis of a lens to which parallel rays of light converge or from which they appear to diverge after refraction.

[0066] The light transmitted by the collimating lens may impinge the transmission grating parallel to the normal of the surface of the transmission grating on which the detection light impinges. The light transmitted by the collimating lens may impinge the transmission grating angled in respect to the normal of the surface of the transmission grating on which the detection light impinges. The surface of the transmission grating on which the detection light impinges may be the surface that is facing away from the detector. The surface of the transmission grating on which the detection light impinges may be the surface from which the transmitted detection light enters the transmission grating and propagates through the transmission grating.

[0067] The focusing optical element may be an integral part of the transmission grating. The term “integral” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a state wherein two or more components are arranged in a space-saving or compact manner. At least one of the two or more components may be permanently built into at least another one of the two or more components. The transmission grating and the focusing optical element may preferably form a single piece. The transmission grating and the focusing optical element may be permanently built into each other or may be manufactured in one single piece.

[0068] The spectrometer device may comprise at least one light emitting element. The light emitting element may be configured for emitting illumination light for illuminating the at least one object in order to generate detection light from the at least one object.

[0069] The term “light emitting element”, also referred to as an “illumination source”, as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an arbitrary device configured for generating or providing light, preferably “illumination light”. The light emitting element specifically may be or may comprise at least one electrical light source.

[0070] The light emitting element may be a thermal radiator. The thermal radiator may be selected from an incandescent lamp or a thermal infrared emitter. The term “incandescent lamp” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of or- 240380W001

[0071] - 14 - dinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an electric light having a heatable element, such as a wire filament, which is capable of being heated to a temperature at which it emits light, especially infrared light. Since the incandescent lamp can, therefore, be considered as a thermal emitter within the infrared spectral range, an emission power of the incandescent lamp decreases with increasing wavelength. The thermal radiator may be selected from an incandescent lamp or a thermal infrared emitter. The term “thermal infrared emitter” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a micro-machined thermally emitting device, which comprises a radiation emitting surface as the light emitting element that emits the optical radiation to be monitored.

[0072] Alternatively or in addition, the light emitting element may be a microelectromechanical system (MEMS)-based emitter. The term “microelectromechanical system (MEMS)-based emitter” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an arbitrary apparatus configured for generating and / or emitting light comprising at least one element, wherein the element is associated with MEMS technology. MEMS technology, typically, involves the manufacture of mechanical and / or electrical elements on a microscale, typically below 1 pm or 100 pm or 1 mm or 5 mm or 50 mm. Alternatively or in addition, the light emitting element may be a laser, specifically a vertical cavity surface emitting laser (VCSEL), particularly emitting at least one wavelength in the infrared region.

[0073] The term “vertical-cavity surface-emitting laser” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a semiconductor laser diode configured for laser beam emission perpendicular with respect to a top surface. VCSELs are generally known to the skilled person such as from WO 2017 / 222618 A.

[0074] Alternatively or in addition, the radiation emitting element may be a light-emitting diode (LED), specifically a LED emitting light that is at least partially located in the infrared spectral range. Alternatively or in addition, the radiation emitting element may be a LED emitting light that is illuminating a luminescent material, specifically a phosphor, for light-conversion of light generated 240380W001

[0075] - 15 - by the LED, wherein the luminescent material generates converted light that is at least partly located in the near-infrared spectral range.

[0076] The term “light-emitting diode” or briefly “LED”, as used herein, is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an optoelectronic semiconductor device capable of emitting light when an electrical current flows through the device. The optoelectronic semiconductor device may be configured for generating the light due to various physical processes, including one or more of spontaneous emission, induced emission, decay of metastable excited states and the like. Thus, as an example, the light-emitting diode, may comprise one or more of: a light-emitting diode based on spontaneous emission of light, in particular an organic light emitting diode, a light-emitting diode based on superluminescence (sLED), or a laser diode (LD). In the following, without narrowing the possible embodiments of the light-emitting diode to any of the before-mentioned physical principles or setups, the abbreviation “LED” will be used for any type of light-emitting diode.

[0077] Specifically, the LED may comprise at least two layers of semiconductor material, wherein light may be generated at at least one interface between the at least two layers of semiconductor material, specifically due to a recombination of positive and negative electrical charges, e.g. due to electron-hole recombination. The at least two layers of semiconductor material may have differing electrical properties, such as at least one of the layers being an n-doped semiconductor material and at least one of the layers being a p-doped semiconductor material. Thus, as an example, the LED may comprise at least one pn-junction and / or at least one pin-set up. It shall be noted, however, that other device structures are feasible, too. The at least one semiconductor material may specifically be or may comprise at least one inorganic semiconducting material. It shall be noted, however, that organic semiconducting materials may be used additionally or alternatively.

[0078] Generally, the LED may convert electrical current into light, specifically light that is at least partially located in the infrared spectral range. Alternatively or in addition, LED may convert electrical current into primary light, more specifically into blue primary light. The LED, thus, specifically may be a blue LED. The LED may be configured for generating the primary light, particularly for the light-conversion in the phosphor, also referred to as the “pump light”. Thus, the LED may also be referred to as the “pump LED”. The LED specifically may comprise at least one LED chip and / or at least one LED die. Thus, the semiconductor element of the LED may comprise an LED bare chip. 240380W001

[0079] - 16 -

[0080] The term “luminescence” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to the process of spontaneous emission of light by a substance not resulting from heat. Specifically, luminescence may refer to a cold-body radiation. More specifically, the luminescence may be initiated or excited by irradiation with light, in which case the luminescence is also referred to as “photoluminescence”. The property of a material being capable of performing luminescence, in the context of the present invention, is referred to by the adjective “luminescent”. The at least one luminescent material specifically may be a photoluminescent material, i.e. a material which is capable of emitting light after absorption of photons or excitation light. Specifically, the luminescent material may have a positive Stokes shift, which generally may refer to the fact that the secondary light is red-shifted with respect to the primary light.

[0081] The at least one luminescent material, thus, may form at least one converter, also referred to as a light converter, transforming primary light into secondary light having different spectral properties as compared to the primary light. Specifically, a spectral width of the secondary light may be larger than a spectral width of the primary light, and / or a center of emission of the secondary light may be shifted, specifically red-shifted, compared to the primary light. Specifically, the at least one luminescent material may have an absorption in the ultraviolet and / or blue spectral range and an emission in the near-infrared and / or infrared spectral range. Thus, generally, the luminescent material or converter may form at least one component of the phosphor LED converging primary light or pump light, specifically in the blue spectral range, into light having a longer wavelength, e.g. in the near-infrared or infrared spectral range.

[0082] The luminescent material, specifically, may, thus, form at least one converter or light converter. The luminescent material may form at least one of a converter platelet, a luminescent and specifically a fluorescent coating on the LED and phosphor coating on the LED. The luminescent material may, as an example, comprise one or more of the following materials: Cerium-doped YAG (YAG:Ce3+, or Y3AI5O12:Ce3+); rare-earth-doped Sialons; copper- and aluminum-doped zinc sulfide (ZnS:Cu,AI).

[0083] The LED and the luminescent material, together, may form a so-called “phosphor LED”. Consequently, the term “phosphor light-emitting diode” or briefly “phosphor LED”, as used herein, is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a combination of at least one light-emitting diode configured for generating primary light or pump light, and at least one luminescent material, also referred to as a 240380W001

[0084] - 17 -

[0085] “phosphor”, configured for light-conversion of the primary light generated by the light-emitting diode. The phosphor LED may form a packaged LED light source, including the LED die, e.g. a blue LED emitting blue pump light, as well as the phosphor, which, as an example, fully or partially coats the LED, which is, as an example, configured for converting the primary light or blue light into light having differing spectral properties, specifically into near-infrared light. Generally, the phosphor LED may be packaged in one housing or may be unpackaged. Thus, the LED and the at least one luminescent material for light-conversion of the primary light generated by the light-emitting diode may specifically be housed in a common housing. Alternatively, however, the LED may also be an unhoused or bare LED which may fully or partially be covered with the luminescent material, such as by disposing one or more layers of the luminescent material on the LED die. The phosphor LED, generally, may form an emitter or light source by itself.

[0086] The illumination light may have a spectral range at least partially located in the near-infrared spectral range, specifically in the spectral range from 1 to 3 pm, preferably from 1.3 to 2.5 pm, more preferably from 1 .5 to 2.2 pm.

[0087] The spectrometer device may comprise an evaluation unit configured to evaluate detector signal generated by the detector and, thereby, determine the item of spectral information on the object. The term “to evaluate”, as used herein, is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to the process of processing at least one first item of information in order to generate at least one second item of information thereby. Consequently, the term “evaluation unit”, as used herein, is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an arbitrary device or a combination of devices configured to evaluate or process at least one first item of information, in order to generate at least one second item of information thereof. Thus, specifically, the evaluation unit may be configured for processing at least one input signal and to generate at least one output signal thereof. The at least one input signal, as an example, may comprise at least one detector signal provided directly or indirectly by the at least one photosensitive detector.

[0088] As an example, the evaluation unit may be or may comprise one or more integrated circuits, such as one or more application-specific integrated circuits (ASICs), and / or one or more data processing devices, such as one or more of computers, digital signal processors (DSP), field programmable gate arrays (FPGA) preferably one or more microcomputers and / or microcontrollers. Additional components may be comprised, such as one or more preprocessing devices 240380W001

[0089] - 18 - and / or data acquisition devices, such as one or more devices for receiving and / or preprocessing of the detector signals, such as one or more AD-converters and / or one or more filters. Further, the evaluation unit may comprise one or more data storage devices. Further, the evaluation unit may comprise one or more interfaces, such as one or more wireless interfaces and / or one or more wire-bound interfaces.

[0090] In a further aspect, a mobile device is disclosed, wherein the mobile communication device comprises a spectrometer device. The term “mobile device” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a mobile electronics de-vice more specifically to a mobile communication device, configured for providing access to at least one telecommunication network, such as a cell phone, smart phone or a wearable. The mobile device may be a portable device. For this aspect, reference may be made to any further aspect, particularly any definition, Embodiment or claim given in the context of any further aspect.

[0091] The term “portable” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to the property of at least one object of being moved by human force, such as by a single user. Specifically, the object characterized by the term “portable” may have a weight not exceeding 10 kg, specifically not exceeding 5 kg, more specifically not exceeding 1 kg or even not exceeding 500 g. Additionally or alternatively, the dimensions of the object characterized by the term “portable” may be such that the object extends by no more than 0.3 m into any dimension, specifically by no more than 0.2 m into any dimension. The object, specifically, may have a volume of no more than 0.03 m3, specifically of no more than 0.01 m3, more specifically no more than 0.001 m3or even no more than 500 mm3. In particular, as an example, the portable spectrometer device may have dimensions of e.g. 10 mm by 10 mm by 5 mm. Specifically, the portable spectrometer device may be part of a mobile device or may be attachable to a mobile device, such as a notebook computer, a tablet, a cell phone, such as a smart phone, a smartwatch and / or a wearable computer, also referred to as “wearable”, e.g. a body borne computer such as a wrist band or a watch. In particular, the a weight of the spectrometer device, specifically the portable spectrometer device, may be in the range from 1 g to 100 g, more specifically in the range from 1 g to 10 g.

[0092] In a further aspect, a method for obtaining spectroscopic information on at least one object by using a spectrometer device is disclosed, wherein the method comprises using a spectrometer 240380W001

[0093] - 19 - device. For this aspect, reference may be made to any further aspect, particularly any definition, Embodiment or claim given in the context of any further aspect.

[0094] The spectrometer device, a mobile device and a method for obtaining spectroscopic information on at least one object by using a spectrometer device discussed elsewhere herein provide a large number of advantages over known devices and methods of similar kind.

[0095] Particularly, the present disclosure relates to a spectrometer device, a mobile device and a method for obtaining spectroscopic information on at least one object by using a spectrometer device that enable an improved separation of non-totally reflected and totally reflected light traversing through a transmission grating in order to improve the spectroscopic quality. The spectrometer device may be configured such that only the main peak illuminates the detector.

[0096] As used herein, the terms “have”, “comprise” or “include” or any arbitrary grammatical variations thereof are used in a non-exclusive way. Thus, these terms may both refer to a situation in which, besides the feature introduced by these terms, no further features are present in the entity described in this context and to a situation in which one or more further features are present. As an example, the expressions “A has B”, “A comprises B” and “A includes B” may both refer to a situation in which, besides B, no other element is present in A (i.e. a situation in which A solely and exclusively consists of B) and to a situation in which, besides B, one or more further elements are present in entity A, such as element C, elements C and D or even further elements.

[0097] Further, it shall be noted that the terms “at least one”, “one or more” or similar expressions indicating that a feature or element may be present once or more than once typically are used only once when introducing the respective feature or element. In most cases, when referring to the respective feature or element, the expressions “at least one” or “one or more” are not repeated, nonwithstanding the fact that the respective feature or element may be present once or more than once.

[0098] Further, as used herein, the terms "preferably", "more preferably", "particularly", "more particularly", "specifically", "more specifically" or similar terms are used in conjunction with optional features, without restricting alternative possibilities. Thus, features introduced by these terms are optional features and are not intended to restrict the scope of the claims in any way. The invention may, as the skilled person will recognize, be performed by using alternative features. Similarly, features introduced by "in an embodiment of the invention" or similar expressions are intended to be optional features, without any restriction regarding alternative embodiments of the 240380W001

[0099] - 20 - invention, without any restrictions regarding the scope of the invention and without any restriction regarding the possibility of combining the features introduced in such way with other optional or non-optional features of the invention.

[0100] Summarizing and without excluding further possible embodiments, the following embodiments may be envisaged:

[0101] Embodiment 1 : A spectrometer device for obtaining at least one item of spectral information on at least one object by spectroscopic measurement, comprising a detector configured for detecting detection light from the at least one object, the detector comprising a plurality of photosensitive elements, a transmission grating, wherein the transmission grating comprises a grating structure and a substrate body, wherein the grating structure is configured such that the plurality of photosensitive elements are exposed to a differing spectral range of the detection light, wherein the substrate body comprises a first surface and a second surface, wherein the first surface is opposite of the second surface, wherein the first surface is a straight line in a cross-sectional plane, wherein the second surface is a straight line in the cross-sectional plane, wherein the grating structure is arranged on the first surface, at least one focusing optical element configured to receive detection light from the transmission grating, wherein a focus point of the focusing optical element coincides with the detector, wherein the detection light is propagating from the transmission grating through the focusing optical element onto the detector, wherein a normal of the first surface and a normal of the second surface that are tilted in respect to each other, wherein the normal of the first surface and the normal of the second surface lie in the cross-sectional plane.

[0102] Embodiment 2: The spectrometer device according to the preceding Embodiment, wherein, for the normal of the first surface and the normal of the second surface being tilted in respect to each other, an angle between the normal of the first surface and the normal of the second surface is between 0.5° and 10°, preferably 2° and 8°, more preferably 5° and 7°.

[0103] Embodiment 3: The spectrometer device according to any one of the preceding Embodiments, wherein the first surface and the second surface each are planar surfaces. 240380W001

[0104] - 21 -

[0105] Embodiment 4: The spectrometer device according to any one of the preceding Embodiments, wherein the substrate body has a wedged shaped portion in the cross-sectional plane, wherein the first surface and the second surface are convergent surfaces of the wedged shaped portion.

[0106] Embodiment 5: The spectrometer device according to the preceding Embodiment, wherein the substrate body has at least one further wedged shaped portion in the cross-sectional plane, wherein the further wedged shaped portion is different from the wedged shaped portion; particularly wherein the substrate body comprises at least one further first surface and at least one further second surface, wherein the at least one further first surface is opposite of the at least one further second surface, wherein the at least one further first surface is a straight line in the cross-sectional plane, wherein the at least one further second surface is a straight line in the cross-sectional plane, wherein the at least one further first surface and the at least one further second surface are convergent surfaces of the at least one further wedged shaped portion.

[0107] Embodiment 6: The spectrometer device according to the preceding Embodiment, wherein the wedged shaped portion and the at least one further wedged shaped portion are concentrically arranged around a center axis, wherein the center axis lies on the cross-sectional plane.

[0108] Embodiment 7: The spectrometer device according to any one of the preceding Embodiments, wherein at least one of: the first surface; the second surface is configured for receiving detection light incident on the transmission grating.

[0109] Embodiment 8: The spectrometer device according to any one of the preceding Embodiments, wherein the refractive index of the substrate body is below 1.43, preferably below 1.35, more preferably 1.3; or above 1.45, preferably above 2.0, more preferably 3.4.

[0110] Embodiment 9: The spectrometer device according to any one of the preceding Embodiments, wherein a height between the first surface and the second surface is below 1 mm, preferably o below 0.47 mm for a refractive index of the substrate body of 1 .3; or o below 0.14 mm for a refractive index of the substrate body of 3.4. 240380W001

[0111] - 22 -

[0112] Embodiment 10: The spectrometer device according to any one of the preceding Embodiments, wherein a material of the substrate body is or comprises at least one of: silicon;

[0113] - fused silica; an optical glass; a synthetic material and / or plastic material

[0114] Calciumfluorid

[0115] - Zinc selenide.

[0116] Embodiment 11 : The spectrometer device according to any one of the preceding Embodiments, wherein a material of the grating structure is or comprises at least one of: silicon;

[0117] - fused silica; an optical glass; a synthetic material and / or plastic material;

[0118] Calciumfluorid;

[0119] - Zinc selenide.

[0120] Embodiment 12: The spectrometer device according to any one of the preceding Embodiments, wherein the spectrometer device is configured such that only a specific diffraction order, particularly the +1st diffraction order, of the light transmitted through the transmission grating is directed onto the detector.

[0121] Embodiment 13: The spectrometer device according to the preceding Embodiment, wherein, for the spectrometer device to be configured such that only the specific diffraction order of the light transmitted through the transmission grating is directed onto the detector, the spectrometer comprises at least one aperture configured for blocking at least one diffraction order of light transmitted through the transmission grating that differs from only the specific diffraction order.

[0122] Embodiment 14: The spectrometer device according to the preceding Embodiment, wherein the at least one aperture configured for blocking the at least one diffraction order is arranged between the transmission grating and the at least one focusing optical element. 240380W001

[0123] - 23 -

[0124] Embodiment 15: The spectrometer device according to any one of the three preceding Embodiments, wherein the grating structure defines a planar grating surface, wherein the detector defines a planar detector surface, wherein, for the spectrometer device being configured such that only the specific diffraction order of the light transmitted through the transmission grating is directed onto the detector, the normal of the surface of the transmission grating from which the detection light emerges and a normal of the planar detector surface are tilted in respect to each other.

[0125] Embodiment 16: The spectrometer device according to the preceding Embodiment, wherein, for the normal of the surface of the transmission grating from which the detection light emerges and the normal of the planar detector surface to be tilted in respect to each other, an angle between the normal of the surface of the transmission grating from which the detection light emerges and the normal of the planar detector surface is between 1° and 45°, more preferably 5° and 30°.

[0126] Embodiment 17: The spectrometer device according to any one of the preceding Embodiments, wherein the spectrometer device comprises at least one sample interface, wherein the sample interface defines a measurement surface, wherein the measurement surface is configured for defining a measurement pose of the at least one object.

[0127] Embodiment 18: The spectrometer device according to the preceding Embodiment, wherein the spectrometer device comprises at least one aperture configured to receive detection light from the at least one sample interface, wherein the detection light is propagating through the collimating lens onto the transmission grating.

[0128] Embodiment 19: The spectrometer device according to the preceding Embodiment, wherein the spectrometer device comprises at least one collimating lens, wherein a focus point of the collimating lens coincides with the aperture, wherein the detection light is propagating from the aperture through the collimating lens onto the transmission grating.

[0129] Embodiment 20: The spectrometer device according to the preceding Embodiment, wherein the light transmitted by the collimating lens impinges the transmission grating parallel to the normal of the surface of the transmission grating on which the detection light impinges.

[0130] Embodiment 21 : The spectrometer device according to Embodiment 18, wherein the light transmitted by the collimating lens impinges the transmission grating angled in respect to the normal of the surface of the transmission grating on which the detection light impinges. 240380W001

[0131] - 24 -

[0132] Embodiment 22: The spectrometer device according to any one of the preceding Embodiments, wherein the focusing optical element is selected from at least one of: an optical lens; an optical mirror.

[0133] Embodiment 23: The spectrometer device according to any one of the preceding Embodiments, wherein the focusing optical element is an integral part of the transmission grating.

[0134] Embodiment 24: The spectrometer device according to any one of the preceding Embodiments, wherein the grooves formed by the grating structure expand in a direction that is parallel to a vertex-base axis defined by the transmission grating, wherein the vertex-base axis runs from the narrow end of the transmission grating to the wide end of the transmission grating.

[0135] Embodiment 25: The spectrometer device according to any one of the preceding Embodiments, wherein the spectrometer device comprises at least one light emitting element, wherein the light emitting element is configured for emitting illumination light for illuminating the at least one object in order to generate detection light from the at least one object.

[0136] Embodiment 26: The spectrometer device according to the preceding Embodiment, wherein the light emitting element is at least one of:

[0137] - a thermal radiator;

[0138] - a microelectromechanical system (MEMS)-based emitter;

[0139] - a laser, specifically a vertical cavity surface emitting laser (VCSEL), particularly emitting at least one wavelength in the infrared region;

[0140] - a light-emitting diode (LED), particularly o a LED emitting light that is at least partially located in the infrared spectral range and / or o a LED illuminating a phosphor for light-conversion of light generated by the LED, wherein the luminescent material generates converted light that is at least partly located in the near-infrared spectral range.

[0141] Embodiment 27: A mobile device, wherein the mobile communication device comprises a spectrometer device according to any one of the preceding Embodiments. 240380W001

[0142] - 25 -

[0143] Embodiment 28: A method for obtaining spectroscopic information on at least one object by using a spectrometer device, wherein the method comprises using a spectrometer device according to any one the preceding Embodiments.

[0144] Short description of the Figures

[0145] Further optional features and embodiments will be disclosed in more detail in the subsequent description of embodiments, preferably in conjunction with the dependent claims. Therein, the respective optional features may be realized in an isolated fashion as well as in any arbitrary feasible combination, as the skilled person will realize. The scope of the invention is not restricted by the preferred embodiments. The embodiments are schematically depicted in the Figures. Therein, identical reference numbers in these Figures refer to identical or functionally comparable elements.

[0146] In the Figures:

[0147] Figure 1 shows images of the 0thdiffraction order and the 1stdiffraction order from a typical transmission grating; and

[0148] Figure 2 shows a typical transmission grating;

[0149] Figure 3 shows an exemplary spectrometer device comprising a transmission grating;

[0150] Figure 4 shows a further exemplary transmission grating;

[0151] Figure 5 shows a further exemplary transmission grating;

[0152] Figure 6 shows a further exemplary transmission grating;

[0153] Figure 7 shows a further exemplary spectrometer device; and

[0154] Figure 8 shows a further exemplary transmission grating.

[0155] Detailed description of the embodiments 240380W001

[0156] - 26 -

[0157] For spectrometer devices 110, transmission gratings 120 are typically used to distribute light according to its wavelength. Based on diffraction, transmission gratings 120 disperse the light into a spectrum, allowing a distinct investigation of the wavelength.

[0158] Transmission gratings 120 comprise grooves, which are closely and equally spaced and applied on a substrate of a height d. The grooves on the substrate may act as a series of parallel slits, resulting in diffraction and thus in an interference pattern. The diffraction orders of the interference pattern may be determined via the equation wherein a is the angle of the incident light with the wavelength A, g is the groove density, k is the order of diffraction and 6kis the angle of *hdiffraction order.

[0159] Figure 1 shows two images recorded by using a short wave infrared camera of the 0thdiffraction order and the 1stdiffraction order from a typical transmission grating. The transmission grating 120 was illuminated with a single laser spot, which has the wavelength of 1545 nm. In both images two spots appear. The left side spot is weaker in intensity and comes from total internal reflections of the laser light within the transmission grating. The brighter main spot in the right is caused by non-totally reflected light, which is typically taken for spectrometry. However, the side spot caused by the total internal reflection peak may have a large unwanted effect on the spectroscopic quality of the spectrometer device 110, particularly when the diffracted beams are focused via a lens on a detector. Due to lens aberrations, the resulting peak on the detector may even be broadened and / or get some artifacts such as shoulders on the peak backs.

[0160] In Figure 2, a typical transmission grating 120 is depicted. As may be derived from Figure 2, the transmission grating generates a plurality of differing refraction orders from the light 121 impinging on the transmission grating. In Figure 2, three diffraction orders of the transmitted light 121 are depicted, namely the 0thdiffraction order 150, 156, the +1stdiffraction order 152, 158 and the +2nddiffraction order 154, 160. Further, the total refraction of the light 121 within the transmission grating is indicated with the dotted lines. The diffraction orders 150, 152 and 154 are generated by the non-totally reflected light 121. The diffraction orders 156, 158 and 160 are generated by totally reflected light 121. The 0thdiffraction order 156 may not be transmitted as the angle is too large such that total reflection will appear. 240380W001

[0161] - 27 -

[0162] For determining the corresponding angles 0bs mfor a specific diffraction order m that is resulting k-A from a beam offset 2 ■ S-L = 2d ■ tan ?2. it is used that sin 0k= — - sina-t . By further using the

[0163] Snell’s law n sin(0k) = —n2sin(0'k), it follows that

[0164] In an example, it holds that

[0165] For the side peak and for the main peak it follows that

[0166] This can be substituted again with Snell’s law:

[0167] The final equation for k=-1 becomes:

[0168] If (m - 1) = k, internal reflection will lead to a second ray of mthorder with a lateral beam offset, which is parallel to the main ray with the k+1 diffraction order.

[0169] A more general version of this equation with the (m+ )thorder of any main peak and the mthorder of a resulting side peak can be determined in the same way and would have the following final from:

[0170] As already discussed, in a spectrometer device 110, a side spot due caused by internal reflection will lead to wrong information. In the following spectrometer devices 110, the side spot caused by internal reflections is suppressed.

[0171] The spectrometer device 110 is configured such that only a specific diffraction order, particularly the +1stdiffraction order, of the light transmitted through the transmission grating may be directed onto the detector.

[0172] In Figure 3, a spectrometer device 110 for obtaining at least one item of spectral information on at least one object 112 by spectroscopic measurement is disclosed. 240380W001

[0173] - 28 -

[0174] The spectrometer device 110 may comprise at least one sample interface 114, wherein the sample interface may define a measurement surface, wherein the measurement surface may be configured for defining a measurement pose of the at least one object 112. As exemplarily depicted, a mobile device148 may comprise the spectrometer device 110.

[0175] The spectrometer device 110 may comprise at least one aperture 116, specifically a slit, configured to receive detection light 122 from the at least one sample interface, wherein the detection light 122 may be propagating through the aperture 116 onto the transmission grating 120. The spectrometer device 110 may comprise at least one further focusing lens 190 configured to collect the detection light 122 from the at least one sample interface 114, wherein the detection light 122 is propagating through the further focusing lens 190 onto the aperture 116. The further focusing lens 190 may have a further focus point, wherein the further focus point coincides with the aperture 116.

[0176] The spectrometer device 110 may comprise at least one collimating lens 118, wherein a focus point of the collimating lens 118 coincides with the aperture 116, wherein the detection light 122 is propagating from the aperture through the collimating lens 118 onto the transmission grating 120. The detection light 122 received from the sample interface 114 may travers, at first, through the aperture 116 and then through the collimating lens 118 onto the transmission grating 120. As may be derived from Figure 3, the collimating lens 118 is configured to collect the detection light 122 from the aperture 116 and to align the incoming light rays of the detection light 122 into parallel light rays, wherein the parallel light rays impinge on the transmission grating 120.

[0177] The spectrometer comprises a detector 138 configured for detecting detection light 122 from the at least one object 112, the detector comprising a plurality of photosensitive elements 140.

[0178] As already indicated, the spectrometer device 110 comprises

[0179] - the transmission grating 120, wherein the transmission grating comprises a grating structure 124 and a substrate body 126, wherein the grating structure 124 is configured such that the plurality of photosensitive elements 140 are exposed to a differing spectral range of the detection light 122, wherein the substrate body 126 comprises a first surface 128 and a second surface 130, wherein the first surface 128 is opposite of the second surface 130, wherein the first surface is a straight line in a cross- sectional plane, wherein the second surface is a straight line in the cross-sectional plane, wherein the grating structure 124 is arranged on the first surface, 240380W001

[0180] - 29 - at least one focusing optical element 136 configured to receive detection light 122 from the transmission grating 120, wherein a focus point of the focusing optical element 136 coincides with the detector 138, wherein the detection light 122 is propagating from the transmission grating 120 through the focusing optical element 136 onto the detector 138, wherein a normal of the first surface 132 and a normal of the second surface 134 that are tilted in respect to each other, wherein the normal of the first surface 132 and the normal of the second surface 134 lie in the cross-sectional plane. The first surface 132 and the second surface 134 each may be planar surfaces. The substrate body 126 may have a wedged shaped portion 170 in the cross-sectional plane, wherein the first surface 132 and the second surface 134 are convergent surfaces of the wedged shaped portion 170. Figure 3 shows the spectrometer device 110 in said cross-sectional plane.

[0181] As shown in Figure 3, the second surface 134 is, exemplarily, configured for receiving the detection light 122 incident on the transmission grating 120. For the normal of the first surface 132 and the normal of the second surface 134 being tilted in respect to each other, an angle between the normal of the first surface and the normal of the second surface 142 may be between 0.5° and 10°, preferably 2° and 8°, more preferably 5° and 7°.

[0182] The refractive index of the substrate body 126 may be below 1.43, preferably below 1.35, more preferably 1.3; or above 1.45, preferably above 2.0, more preferably 3.4. A height 144 between the first surface and the second surface may be below 1 mm, preferably o below 0.47 mm for a refractive index of the substrate body 126 of 1 .3; or o below 0.14 mm for a refractive index of the substrate body 126 of 3.4.

[0183] A material of the substrate body 126 may be or may comprise at least one of: silicon; fused silica; an optical glass; a synthetic material and / or plastic material; Calciumfluorid; Zinc selenide.

[0184] A material of the grating structure 124 may be or may comprise at least one of: silicon; fused silica; an optical glass; a synthetic material and / or plastic material; Calciumfluorid; Zinc selenide. The grating structure may be an integral part of the substrate body.

[0185] As shown in Figure 3, the detection light 122 transmitted by the collimating lens 118 may impinge the transmission grating 120 angled in respect to the normal of the respective surface 132, 134 on which the detection light 122 impinges. Here, the detection light 122 transmitted by the collimating lens 118 impinges, exemplarily the transmission grating 120 angled in respect to 240380W001

[0186] - 30 - the normal of the second surface 134. As a result, the parallel light rays generated by the collimating lens 118 may be tilted in respect to the normal of the respective surface 132, 134 when said parallel light rays impinge the respective surface 132, 134 of the transmission grating 120.

[0187] The spectrometer device 110 comprises at least one focusing optical element 136 configured to receive detection light 122 from the transmission grating 120. The focusing optical element 136 may be selected from at least one of: an optical lens; an optical mirror.The light rays of the detection light 122 received by the focusing optical element136 from the transmission grating 120 may be parallel light rays. The focusing optical element 136 may be configured to focus the incoming parallel light rays on the detector 138, specifically the photosensitive elements 140 of the detector 138. A focus point of the focusing optical element 136 may coincide with the detector 136, wherein the detection light 122 may be propagating from the transmission grating 120 through the focusing optical element 136 onto the detector 138.

[0188] For the spectrometer device 110 to be configured such that only the specific diffraction order of the light transmitted through the transmission grating is directed onto the detector, the spectrometer comprise at least one aperture 162 configured for blocking at least one diffraction order of detection light 122 transmitted through the transmission grating 120 that differs from only the specific diffraction order. As exemplarily depicted in Figure 3, the at least one aperture 162 configured for blocking the at least one diffraction order is arranged between the transmission grating 120 and the at least one focusing optical element 136.

[0189] The grating structure 124 may define a planar grating surface, wherein the detector may define a planar detector surface, wherein, for the spectrometer device 110 being configured such that only the specific diffraction order of the detection light 122 transmitted through the transmission grating 120 is directed onto the detector 138, the normal of the respective surface 132, 134 of the transmission grating 120 from which the detection light 122 emerges and a normal of the planar detector surface 164 may be tilted in respect to each other. For the normal of the respective surface 132, 134 of the transmission grating 120 from which the detection light 122 emerges and the normal of the planar detector surface 164 to be tilted in respect to each other, an angle between the normal of the respective surface 132, 134 of the transmission grating 120 from which the detection light 122 emerges and the normal of the planar detector surface 166 may be between 1° and 45°, more preferably 5° and 30°. 240380W001

[0190] - 31 -

[0191] The spectrometer device 110 may comprise at least one light emitting element 146. The light emitting element 146 may be configured for emitting illumination light 148 for illuminating the at least one object 112 in order to generate detection light 122 from the at least one object 112.

[0192] The light emitting element 146 may be at least one of:

[0193] - a thermal radiator;

[0194] - a microelectromechanical system (MEMS)-based emitter;

[0195] - a laser, specifically a vertical cavity surface emitting laser (VCSEL), particularly emitting at least one wavelength in the infrared region;

[0196] - a light-emitting diode (LED), particularly o a LED emitting light that is at least partially located in the infrared spectral range and / or o a LED illuminating a phosphor for light-conversion of light generated by the LED, wherein the luminescent material generates converted light that is at least partly located in the near-infrared spectral range.

[0197] The spectrometer device 110 may comprise an evaluation unit 176 configured to evaluate detector signal generated by the detector 138 and, thereby, determine the item of spectral information on the object 112.

[0198] As may be derived from Figure 4, which shows a further exemplary transmission grating 124 arranged in a further exemplary spectrometer device 110, the detection light 122 transmitted by the collimating lens 118, specifically the parallel light rays of the detection light 122 generated by the collimating lens 118, may impinge the transmission grating 120 angled in respect to the normal of the respective surface 132, 134 on which the detection light 122 impinges.

[0199] In Figure 4, the 0thdiffraction order of the non-totally reflected light 150 and the 0thdiffraction order of the totally reflected detection light 158 are depicted. As may be derived from Figure 4, the 0thdiffraction order of the non-totally reflected light 150 and the 1stdiffraction order of the totally reflected detection light 158 are well separated. The grating structure 124 may be arranged on the first surface 128, as depicted. Alternatively, the grating structure 124 may be arranged on the second surface 130 (not depicted). 240380W001

[0200] - 32 -

[0201] To calculate a desired angle between the normal of the first surface and the normal of the second surface 142, the angle difference A8 between the 0thdiffraction order of the non-totally reflected light 150 and the 1thdiffraction order of the totally reflected detection light 158 must be given. If this is clear, the angles may have the following relations:

[0202] Yi = Pi + "

[0203] P2=Yi +M =Pi + 2 to

[0204] From the upper relations and Snell’s law sinai = n2sina2it follows that

[0205] As may be derived from Figure 5, which shows a further exemplary transmission grating 124 arranged in a further exemplary spectrometer device 110, the detection light 122 transmitted by the collimating lens, specifically the parallel light rays of the detection light 122 generated by the collimating lens, may impinge the transmission grating parallel to the normal of the respective surface 132, 134 on which the detection light 122 impinges.

[0206] In Figure 5, the 0thdiffraction order of the non-totally reflected light 150 and the 1thdiffraction order of the totally reflected detection light 158 are depicted. As may be derived from Figure 5, the 0thdiffraction order of the non-totally reflected light 150 and the 1thdiffraction order of the totally reflected detection light 158 are well separated. The grating structure 124 may be arranged on the first surface 128, as depicted. Alternatively, the grating structure 124 may be arranged on the second surface 130 (not depicted).

[0207] As may be derived from Figure 6, which shows a further exemplary transmission grating 124 arranged in a further exemplary spectrometer device 110, the substrate body 126 may have said wedged shaped portion 170 and at least one further wedged shaped portion 168 in the cross- sectional plane, wherein the further wedged shaped portion may be different from the wedged shaped portion. The substrate body 126 may comprise at least one further first surface 172 and at least one further second surface 174. The at least one further first surface 172 may be opposite of the at least one further second surface 174, wherein the at least one further first surface 172 may be a straight line in the cross-sectional plane, wherein the at least one further second surface 174 is a straight line in the cross-sectional plane. The at least one further first surface 172 and the at least one further second surface 174 may be convergent surfaces of the at least one further wedged shaped portion. 240380W001

[0208] - 33 -

[0209] The wedged shaped portion 170 and the at least one further wedged shaped portion 168 may be concentrically arranged around a center axis 178, wherein the center axis 178 lies on the cross-sectional plane. Thereby, the transmission grating 124 may be or may be comprised by a Fresnel lens.

[0210] As may be derived from Figure 7, which shows a further exemplary transmission grating 124 arranged in a further exemplary spectrometer device 110, the focusing optical element136 may be an integral part of the transmission grating 120.

[0211] As may be derived from Figure 8, which shows a further exemplary transmission grating 124 arranged in a further exemplary spectrometer device 110, the grooves 180 formed by the grating structure 124 may expand in a direction 182 that is parallel to a vertex-base axis 184 defined by the transmission grating 120, wherein the vertex-base axis 184 runs from a narrow end 186 of the transmission grating 120 to a wide end 188 of the transmission grating 120. As may be derived from the further Figures, the grooves 180 comprised by the transmission grating 120 may be expand in a direction that is orthogonal to the vertex-base axis 184 defined by the transmission grating 120.

[0212] List of reference numbers

[0213] 110 spectrometer device

[0214] 112 object

[0215] 114 sample interface

[0216] 116 aperture

[0217] 118 collimating lens

[0218] 120 transmission grating

[0219] 121 light

[0220] 122 detection light

[0221] 124 grating structure

[0222] 126 substrate body

[0223] 128 first surface

[0224] 130 second surface

[0225] 132 normal of the first surface

[0226] 134 normal of the second surface

[0227] 136 focusing optical element

[0228] 138 detector

[0229] 140 photosensitive element 240380W001

[0230] - 34 -

[0231] 142 angle between the normal of the first surface and the normal of the second surface

[0232] 144 height

[0233] 146 light emitting element

[0234] 148 illumination light

[0235] 150 0thdiffraction order of non-totally reflected light

[0236] 152 1stdiffraction order of non-totally reflected light

[0237] 154 2nddiffraction order of non-totally reflected light

[0238] 156 0thdiffraction order of totally reflected light

[0239] 158 1stdiffraction order of totally reflected light

[0240] 160 2nddiffraction order of totally reflected light

[0241] 162 aperture

[0242] 164 normal of the planar detector surface

[0243] 166 angle between the normal of the respective surface of the transmission grating from which the detection light emerges and the normal of the planar detector surface

[0244] 168 further wedged shaped portion

[0245] 170 wedged shaped portion

[0246] 172 further first surface

[0247] 174 further second surface

[0248] 176 evaluation unit

[0249] 178 center axis

[0250] 180 grooves

[0251] 182 direction

[0252] 184 vertex-base axis

[0253] 186 narrow end

[0254] 188 wide end

[0255] 190 further focusing lens

Claims

240380W001- 35 -Claims1. A spectrometer device (110) for obtaining at least one item of spectral information on at least one object (112) by spectroscopic measurement, comprising a detector (138) configured for detecting detection light (122) from the at least one object (112), the detector (138) comprising a plurality of photosensitive elements (140), a transmission grating (120), wherein the transmission grating (120) comprises a grating structure (124) and a substrate body (126), wherein the grating structure (124) is configured such that the plurality of photosensitive elements (140) are exposed to a differing spectral range of the detection light (122), wherein the substrate body (126) comprises a first surface (128) and a second surface (130), wherein the first surface (128) is opposite of the second surface (130), wherein the first surface (128) is a straight line in a cross-sectional plane, wherein the second surface (130) is a straight line in the cross-sectional plane, wherein the grating structure (124) is arranged on the first surface (128), at least one focusing optical element (136) configured to receive detection light (122) from the transmission grating (120), wherein a focus point of the focusing optical element (136) coincides with the detector (138), wherein the detection light (122) is propagating from the transmission grating (120) through the focusing optical element (136) onto the detector (138), wherein a normal of the first surface (132) and a normal of the second surface (134) that are tilted in respect to each other, wherein the normal of the first surface (132) and the normal of the second surface (134) lie in the cross-sectional plane, wherein the spectrometer device (110) is configured such that only a specific diffraction order of the light transmitted through the transmission grating (120) is directed onto the detector (138), wherein, for the spectrometer device (110) to be configured such that only the specific diffraction order of the light transmitted through the transmission grating (120) is directed onto the detector (138), the spectrometer comprises at least one aperture (162) configured for blocking at least one diffraction order of light transmitted through the transmission grating (120) that differs from the specific diffraction order.

2. The spectrometer device (110) according to the preceding claim, wherein the at least one aperture (162) configured for blocking the at least one diffraction order is arranged240380W001- 36 - between the transmission grating (120) and the at least one focusing optical element (136).

3. The spectrometer device (110) according to any one of the preceding claims, wherein the substrate body (126) has a wedged shaped portion (170) in the cross-sectional plane, wherein the first surface (128) and the second surface (130) are convergent surfaces of the wedged shaped portion (170).

4. The spectrometer device (110) according to the preceding claim, wherein the substrate body (126) has at least one further wedged shaped portion (168) in the cross- sectional plane, wherein the further wedged shaped portion (168) is different from the wedged shaped portion (170); wherein the wedged shaped portion (170) and the at least one further wedged shaped portion (168) are concentrically arranged around a center axis (178), wherein the center axis (178) lies in the cross-sectional plane.

5. The spectrometer device (110) according to the any one of the preceding claims, wherein the grating structure (124) defines a planar grating surface, wherein the detector (138) defines a planar detector (138) surface, wherein, for the spectrometer device (110) to be configured such that only the specific diffraction order of the light transmitted through the transmission grating (120) is directed onto the detector (138), a normal of the surface (132, 134) of the transmission grating (120) from which the detection light (122) emerges and a normal of the planar detector (138) surface are tilted in respect to each other.

6. The spectrometer device (110) according to the preceding claim, wherein, for the normal of the planar grating surface and the normal of the planar detector (138) surface to be tilted in respect to each other, an angle between the normal of the surface (132, 134) of the transmission grating (120) from which the detection light (122) emerges and the normal of the planar detector (138) surface is between 1° and 45°.

7. The spectrometer device (110) according to any one of the preceding claims, wherein the spectrometer device (110) comprises at least one sample interface (114), wherein the sample interface (114) defines a measurement surface, wherein the measurement surface is configured for defining a measurement pose of the at least one object (112).

8. The spectrometer device (110) according to the preceding claim, wherein the spectrometer device (110) comprises at least one aperture (116) configured to receive the240380W001- 37 - detection light (122) from the at least one sample interface (114), wherein the detection light (122) is propagating through the aperture onto the transmission grating (120).

9. The spectrometer device (110) according to the preceding claim, wherein the spectrometer device (110) comprises at least one collimating lens (118), wherein a focus point of the collimating lens (118) coincides with the aperture, wherein the detection light (122) is propagating from the aperture through the collimating lens (118) onto the transmission grating (120).

10. The spectrometer device (110) according to the preceding claim, wherein the light transmitted by the collimating lens (118) impinges the transmission grating (120) parallel to the normal of the surface (132, 134) of the transmission grating (120) on which the detection light (122) impinges.11 . The spectrometer device (110) according to any one of the claims 8 or 9, wherein the light transmitted by the collimating lens (118) impinges the transmission grating (120) angled in respect to the normal of the surface (132, 134) of the transmission grating (120) on which the detection light (122) impinges.

12. The spectrometer device (110) according to any one of the preceding claims, wherein grooves (180) formed by the grating structure (124) expand in a direction (182) that is parallel to a vertex-base axis (184) defined by the transmission grating (120), wherein the vertex-base axis (184) runs from a narrow end (186) of the transmission grating (120) to a wide end (188) of the transmission grating (120).

13. A mobile device, wherein the mobile communication device comprises a spectrometer device (110) according to any one of the preceding claims.

14. A method for obtaining spectroscopic information on at least one object (112) by using a spectrometer device (110), wherein the method comprises using a spectrometer device (110) according to any one the preceding claims.

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