WO2018149607A1

WO2018149607A1 - Micro-spectrometer, method, and controller for operating a micro-spectrometer

Info

Publication number: WO2018149607A1
Application number: PCT/EP2018/051803
Authority: WO
Inventors: Ingo Herrmann; Andreas Merz; Martin HUSNIK; Benedikt Stein; Christoph Schelling
Original assignee: Robert Bosch Gmbh
Priority date: 2017-02-20
Filing date: 2018-01-25
Publication date: 2018-08-23
Also published as: DE102017202640A1

Abstract

The invention relates to a micro-spectrometer (100) comprising a lighting device (102) for providing light (110), said lighting device (102) being oriented towards a sample location (106) for a sample (114) of the micro-spectrometer (100); a first adjustable filter device (104) for the passage of a first selectable wavelength range (112) of the light (110) from the lighting device (102) to the sample location (106); a detector device (108) for detecting the intensity of the light (116), said detector device (108) being oriented towards the sample location (106); and a second adjustable filter device (200) for the passage of a second selectable wavelength range of the light (116) from the sample location (106) to the detector device (108).

Description

Description title

Microspectrometer, method and controller for operating a

micro spectrometer

State of the art

The invention is based on a device or a method according to the preamble of the independent claims. The subject of the present invention is also a computer program.

In a spectrometer, a spectrum of light can be imaged by a plurality of temporally staggered intensity values. The intensity values can each represent a radiation intensity of a wavelength range. The wavelength range can be adjusted by a tunable filter element.

Disclosure of the invention

Against this background, the approach presented here is used

Microspectrometer, a method for operating a microspectrometer, further a control unit, which uses this method, and finally presented a corresponding computer program according to the main claims. The measures listed in the dependent claims are advantageous developments and improvements in the independent

Claim specified device possible.

When irradiating certain materials or substances with light, the light emitted by the material may be wavelength-shifted with respect to the irradiating light. This allows a reflection spectrum of the Material difficult to interpret, since the shifted wavelengths are superimposed on similar unshifted wavelengths and falsified

Give intensity values.

In the approach presented here, a wavelength range of

be adjusted irradiating light. Likewise, a wavelength range of the light emanating from the material can be set. Thus, the intensities of the wavelength-shifted light can be detected independently and calculated out of the reflection spectrum. Alternatively or additionally, the detection of the shifted wavelengths can be prevented by adjusting the detected wavelength range outside the shifted wavelengths.

A microspectrometer is presented, comprising: a lighting device for providing light, wherein the

Lighting device on a sample site for a sample of

Microspectrometer is aligned; a first tunable filter device for passing a first selectable wavelength range of the light from the illumination device to the sample location; a detector means for detecting an intensity of the light, the detector means being aligned with the sample location; and second tunable filter means for passing a second selectable wavelength range of the light from the sample location to the first

Detector device.

A microspectrometer can be understood as a miniaturized, highly integrated component. An illumination device can have a light source for broadband light. For example, the light source may be an incandescent light source, LED and / or fluorescent light source. The sample location is to be understood as a location that may be one of several possible locations in the vicinity of or in the microspectrometer on which the sample is positioned. The term "sample location" therefore means the position at which the sample is actually arranged for the current measurement.

A filter device can be wavelength-selective and / or modulatable. The filter device may adjust the wavelength range in response to a

Set the wavelength signal. In particular, a wavelength range may be a range close to a set resonance wavelength or a set resonance frequency of the filter device. A

Detector device may comprise a photoelectric element, which is adapted to image the intensity of the light in an electrical value.

The illumination device and the detector device can be arranged in a transmission geometry on opposite sides of the sample location. The illumination device can be designed to illuminate the sample.

The illumination device and the detector device can be aligned in a reflection geometry at an angle to each other on the sample location. For example, the lighting device and the

Detector device may be arranged on the same side of the sample location. The microspectrometer can also have a further illumination device, which is likewise aligned with the sample location from another angle. The light from the illumination device can be (diffusely) reflected or scattered at the sample.

The first filter device and the illumination device can be combined to form a lighting unit. The second filter device and the detector device can be combined to form a detector unit. Both units can be integrated again. By combining compact dimensions of the microspectrometer can be achieved.

The first filter device may comprise at least a first Fabry-Perot filter. The second filter device may comprise at least one second Fabry Include perot filters. A Fabry-Perot filter or interferometer has a gap between two reflective surfaces. A gap width of the gap determines a resonant frequency for incident light in the gap. Light in a wavelength range near the resonance frequency is only slightly attenuated and can pass through the gap. Light outside the set wavelength range is attenuated and does not pass through the interferometer. Fabry-Perot filters are easy to pass through

Adjustable wavelength ranges.

The lighting device can be modulated. A modulable

Light source can provide different wavelength ranges and / or time-varying emit light of different wavelengths. It is also conceivable that the first tunable filter device and / or the second tunable filter device can also be modulated, in particular wherein the first tunable filter device (104) has a modulatable first Fabry-Perot filter and / or a second Fabry-Perot filter. By the

Combination of the modulatable light source and / or filter devices, a particularly narrow-band wavelength range and / or a time-controllable emission of light can be irradiated to the sample. By a clever

Interaction of the filter devices described in more detail below in the illumination and detection module can be provided a very quickly modulated light source and thus a spectrum can be recorded using the lock-in technique. For example, this will be the first

Filter device rapidly between two wavelengths (areas) continuously back and forth process and the second filter device on one of these

Fixed wavelength ranges. A reverse procedure is also conceivable. Thus, a particularly narrowband

Wavelength range and / or a time-controllable release of light can be achieved. For recording a spectrum then the

Wavelength ranges changed accordingly / driven through.

Furthermore, a method for operating a microspectrometer is presented, wherein the method comprises the following steps:

Providing light; Passing a first selectable wavelength range of the light to a sample;

Passing a second selectable wavelength range from the sample; and detecting an intensity of the light from the sample.

The first wavelength range and / or the second wavelength range can be changed over time. In the step of detecting, a temporal spectrum of the light from the sample can be recorded.

The second wavelength range can be varied while the first wavelength range is kept constant. Alternatively, the first

Wavelength range can be varied while the second wavelength range is kept constant. It is also conceivable methods in which both filters are simultaneously varied in different ways to each other (see here, for example, the following explanations). Also, multiple filters may be serially or in parallel before and after the sample instead of a filter. Furthermore, so different spectra can be recorded. Due to the different spectra, wavelength shifts can be easily detected and compensated and / or evaluated accordingly.

The first wavelength range and the second wavelength range can be tuned to different harmonics. Harmonics can be different multiples of a reference wavelength. Different harmonics allow higher order harmonics to be filtered out.

This method can be implemented, for example, in software or hardware or in a mixed form of software and hardware, for example in a control unit.

The approach presented here also provides a control unit which is designed to implement the steps of a variant of a method presented here

to implement, control or implement appropriate facilities. Also by this embodiment of the invention in the form of a control device, the object underlying the invention can be achieved quickly and efficiently.

For this purpose, the control unit may comprise at least one arithmetic unit for processing signals or data, at least one memory unit for storing signals or data, at least one interface to a sensor or an actuator for reading sensor signals from the sensor or for outputting control signals to the actuator and / or or at least one

Communication interface for reading or outputting data embedded in a communication protocol. The arithmetic unit may be, for example, a signal processor, a microcontroller or the like, wherein the memory unit may be a flash memory, an EEPROM or a magnetic memory unit. The communication interface can be designed to read or output data wirelessly and / or by line, wherein a communication interface that can read or output line-bound data, for example, electrically or optically read this data from a corresponding data transmission line or output in a corresponding data transmission line.

In the present case, a control device can be understood as meaning an electrical device which processes sensor signals and outputs control and / or data signals in dependence thereon. The control unit may have an interface, which may be formed in hardware and / or software. In a hardware training, the interfaces may for example be part of a so-called system ASICs, the various functions of the

Control unit includes. However, it is also possible that the interfaces are their own integrated circuits or at least partially consist of discrete components. In a software training, the interfaces may be software modules that are present, for example, on a microcontroller in addition to other software modules.

The microspectrometer may comprise a controller according to the approach presented here. Also of advantage is a computer program product or computer program with program code which can be stored on a machine-readable carrier or storage medium such as a semiconductor memory, a hard disk memory or an optical memory and for carrying out, implementing and / or controlling the steps of the method according to one of the above

described embodiments, in particular when the program product or program is executed on a computer, a mobile device, a smartphone or a device. Embodiments of the approach presented here are shown in the drawings and explained in more detail in the following description. It shows:

Representations of microspectrometers; Fig. 2 is a block diagram of a microspectrometer according to a

Embodiment;

Fig. 3 is a representation of excitation states when excited by

Radiation;

Fig. 4 is an illustration of a Stokes shift;

Fig. 5 is an illustration of various harmonics; Fig. 6 is a representation of a change over time of a

Wavelength range according to an embodiment; and

7 is a flowchart of a method for operating a

Microspectrometer according to one embodiment.

In the following description of favorable embodiments of the present invention are for the in the various figures

represented and similar elements acting the same or similar

Reference numeral used, wherein a repeated description of these elements is omitted. FIG. 1 shows representations of two microspectrometers 100 in different embodiments. Both microspectrometers 100 each have one

Illumination device 102, a tunable filter device 104, a sample location 106 and a detector device 108. At the first

In the case of the microspectrometer 100 shown, the filter device 104 is arranged between the illumination device 102 and the sample location 106. In the second microspectrometer 100 shown, the filter device 104 is arranged between the sample location 106 and the detector device 108.

The illumination device 102 provides broadband light 110. In the first microspectrometer 100, the light 110 is emitted by the filter device 104 to the sample location 106. The filter device 104 passes only a selectable wavelength range 112 of the light 110. At the sample location 106, the light 110 or the wavelength range 112 strikes a sample 114 to be analyzed. The sample 114 interacts with the light 110 or the wavelength range 112. A portion of the light 110 or of the wavelength range 112 is applied to the sample 114 in the direction of the detector device 108 reflected and / or scattered. Alternatively or additionally, the light 110 or the wavelength range 112 excites the sample 114 for emitting light. In this case, the light 116 originating from the sample 114 has wavelengths dependent on a material of the sample 114. The emitted wavelengths can be outside the

Wavelength range 112 are.

In the second illustrated microspectrometer 100, the light 116 emanating from the sample 114 falls in front of the detector device 108

Filter means 104, so that only the wavelength range 112 of the light 116 reaches the detector device 108. In the detector device 108, an intensity of the incident light 116 is imaged in an intensity value. As the filter device 104 transmits different wavelength regions 112 over time, multiple intensity values for the various

Wavelength ranges 112 combined into a spectrum of outgoing from the sample 114 light 116. Spectroscopy systems 100 consist in the vast majority of cases of a light source 102, the sample 114, a filter element 104 and a detector 108. The spectral filter element 104 or a plurality of spectral filter elements 104, such as Fabry-Perot filter (FPI) are either before or after the Sample 114.

With such modern, compact spectroscopy systems 100, very accurate spectra can be recorded. Unlike big and expensive ones

Laboratory spectrometers (for example, by dichroic filter sets), these systems can use 100 wavelength-dependent intensity changes, which are caused by the

Interaction of light with special sample materials arise, do not dissolve.

FIG. 2 shows a block diagram of a microspectrometer 100 according to one exemplary embodiment. The microspectrometer 100 essentially corresponds to one of the microspectrometers shown in FIG. 1 and has a

Illumination device 102, a first tunable filter device 104, a sample location 106 and a detector device 108. In addition, the microspectrometer 100 has a second tunable filter device 200. The first filter device 104 is arranged between the illumination device 102 and the sample 114 or the sample location 106. The second filter device 200 is between the sample 114 and the

Sample location 106 and the detector device 108 arranged. The arrangement can also be reversed.

The first filter device 104 passes a first wavelength range 112 of the light of the illumination device 102 to the sample 114 or the sample location 106. The second filter device 200 passes through a second wavelength range of the light 116 emanating from the sample 114. The first wavelength range 112 and the second wavelength range may be substantially coincident. Likewise, the second wavelength range may deviate from the first wavelength range 112. If the first

Wavelength range 112 and the second wavelength range match, deviating wavelengths are not transmitted to the detector device 108. If the second wavelength range of the first Wavelength range 112 deviates and there is no overlap of

Wavelength ranges 112, then no light comes with the first

Only light in the second wavelength range reaches the detector device 108. For example, the light in the second wavelength range is formed by excitation of the sample 114 for luminescence, in particular, for example, for fluorescence or phosphorescence. In other words, light gets in the second

Wavelength range to the detector device 108 when the sample 114 shifts a spectrum of the first wavelength range 112 in the range of the second wavelength range.

For example, the first wavelength range 112 can be kept constant while the second wavelength range is changed. During the modification, a plurality of

Intensity values recorded. The intensity values represent a spectrum of the sample 114 when irradiated with the first wavelength range 112. Subsequently, the first wavelength range 112 can be changed and again a plurality of intensity values can be detected while the second wavelength range is changed.

Alternatively, the first wavelength range 112 may be changed while the second wavelength range is kept constant. During the

In the detection device 108, a plurality of

Intensity values recorded. The intensity values represent

Wavelength ranges in which the sample 114 reflects or emits when irradiated with a spectrum of light 116. Subsequently, the second wavelength range can be changed and again a plurality of intensity values can be detected while the first wavelength range 112 is changed.

The illumination device 102 and the detector device 108 are aligned with the sample location 106. Here, the illumination device 102 and the detector device 108 are arranged at an angle to each other, so that the light from the illumination device 102 is reflected at the sample 114 and thrown to the detector device 108. The illumination device 102 and the detector device 108 may also be aligned with each other while the sample site 106 is interposed therebetween. Then, the light from the illumination device 102 can penetrate the sample 114 to reach the detector device 108.

In one exemplary embodiment, the first filter device 104 and the illumination device 102 are integrated in a lighting unit 202. The second filter device 200 and the detector device 108 are integrated in a detector unit 204.

A controller 206 for operating the microspectrometer 100 is connected to the illumination unit 202 and the detector unit 204. The

Control unit 206 is configured to control the illumination device 102, the first filter device 104, the second filter device 200 and the detector device via control signals 208. The controller 206 is further configured to record and process the intensity values.

The filter devices 104, 200 can be designed as a Fabry-Perot filter. The transmitted wavelength range is dependent on one

Gap width between two reflective surfaces of the filter device 104, 200. The gap width determines a resonant wavelength, which is little attenuated and therefore is transmitted. The gap width is adjustable. The

Resonance wavelength and its harmonics can penetrate the filter device.

When the first filter means 104 is set to the resonant wavelength and the second filter means 200 is tuned to one of the harmonics, many higher order harmonics can be filtered out (as will be explained later with reference to FIG. 5) and on

low-interference spectrum are recorded and / or a wider range

Wavelength range to be measured trouble-free.

The spectroscopy system 100 presented here consists of two subsystems 202, 204. A first subsystem 202 with a broadband

Lighting system 102 for the illumination of the sample 114 and a first A tunable FPI filter system 104 for spectrally filtering the light in front of the sample 114, and a second subsystem 204 having a second tunable FPI filter system 200 for spectrally filtering the light 116 coming from the sample 114 and a detector system 108.

The subsystems 202, 204 can be positioned either in a transmission geometry, ie on a common optical axis or in reflection geometry relative to each other.

In each case, the illumination system 102 and the first FPI filter system 104 as well as the second FPI filter system 200 and the detector system 108 are compactly integrated together. The FPI filters 104, 200 may be MOEMS elements. Both units 202, 204 may in turn be integrated in a common housing.

In one embodiment, the resonator lengths of the two FPI filter elements 104, 200 are different from each other.

In other words, FIG. 2 shows a spectroscopy system 100 according to the approach presented here with a filter system 104 in front of and a filter system 200 after the sample 114.

By the possibility, as well as before and after the sample 114 the

To be able to set freely transmitted wavelengths with the tunable FPI filter systems 104, 200 and thus to be able to shift against each other, both the non-wavelength shifted scattered / transmitted light and the wavelength-shifted light can be detected and distinguished from each other. Unwanted fluorescent light from the sample 114 can be directly quantified and eliminated, or only the fluorescence light can be determined. As a result, the spectroscopy system 100 provides more accurate spectra. Thus, for example, an additional

Detection arm with dichroic beam splitter and detector, which is perpendicular to the other detection arm saved. This makes the spectroscopy system 100 more compact and cheaper. By different resonator lengths of the two FPIs 104, 200 can be targeted filter out disturbing, especially higher orders and perform dark current reference measurements and background light measurements.

It may be a fast light modulation with a predetermined drive frequency by off-resonance modulation drive of the first FPI filter 104 to

Generation of a lock-in signal are performed (as will be explained in more detail below with reference to FIG. 6).

The illumination system 102 of the spectroscopic system 100 described herein includes a light source and, if necessary, collimating optics. The

Light source may, for example, an incandescent lamp, a thermal emitter, a laser, an LED, an LED with a phosphorus light source or a

Be plasma radiation source. Likewise, the light source can have a plurality of spectrally overlapping radiation sources. The radiation source can be mechanically, optically or electrically modulated to allow lock-in detection.

In the illumination system 202, the first FPI filter system 104 is integrated. This can for example be different from a Fabry-Perot interferometer FPI or several parallel Fabry-Perot interferometers FPI

Wavelength ranges can be set extremely precisely, or several serial FPI filters, for example, to filter out higher orders. The or the FPI elements can be constructed, for example, from a MOEMS element. Thereafter, the light beam 112 is directed to the sample 114.

Depending on the nature of the sample 114, the light 112 radiated thereon may be transmitted, reflected, diffused - scattered, as well as absorbed and remitted, for example, materials containing dye molecules or similar behaviors. In particular, in the last process, the wavelength of the remitted light 116 shifts significantly. In practice, a superposition of these processes usually occurs, which makes massively difficult the evaluation of the acquired spectra. That's why this one is here

approach, the proportion of light 116 emitted wavelength-shifted is quantified. The light 116 from the sample 114 is then directed into the second FPI filter system 200. Depending on the structure of the spectroscopy system 100, various optical components, such as a lens, a reflector, a diffuser directed in particular, and / or an element restricting the field of view can be used for this purpose. Alternatively, these can also be located between FPI and detector. Depending on the application, the FPI filter system 200 can be made of a Fabry-Perot interferometer FPI, several parallel Fabry-Perot interferometers, for example to be able to set extremely precisely in different wavelength ranges, or several serial Fabry-Perot interferometer filters, for example for filtering out higher orders exist. Finally, the light is detected with one or more detectors 108. Depending on the wavelength of the light 116 can also

different detectors 108 may be, for example, Si, Ge, InGaAs or PbSe. Again, the second FPI filter system 200 and the detection system 1108 are integrated together.

The spectroscopy system 100 is controlled by an electronics 206

or the measured data are evaluated via this. To detect very small or noisy signals, the lock-in technique can be used.

In an additional embodiment, the measurement of a portion of the light 112 after the first FPI filter system 104 by means of an additional detector for referencing the incident on the sample 114 light power. To limit the spectral range, further optical filters can be arranged at different points of the beam path. To calibrate the FPI elements 104, 200, fixed references may be included in the spectroscopy system 100. The Vernier effect can be used to create very narrow transmitted wavelength ranges.

Figures 3 and 4 show a representation of various luminescence / photoluminescent processes with excitation states 300, 306, 308 when excited by radiation and a representation of a Stokes shift 400 at a selected molecule. If a fluorescent material is irradiated with light, The fluorophore absorbs a photon and enters an excited state 300. Mostly, energy is then released to the environment through vibrational relaxation 302 before the fluorophore relaxes back to ground state 306 by emission 304 of a photon. Here, the transition 302 may form an "intersystem crossing." The left emission process 304 may be referred to as "intersystem crossing."

Fluorescence, the right transition or emission 304 may be considered as phosporescence. Also, upon emission 304 of a photon, the fluorophore may relax to a higher vibrational state 308 than the ground state 306. Thus, the emitted light 304 is long-wavelength or shifted to lower energies compared to the incident light 110. This effect is referred to as Stokes shift 400.

For certain forms of illumination of the sample and certain

In addition, sample materials can also exhibit an anti-Stokes shift, a phosphorescence or even an inelastic scattering.

The presented approach of a microspectrometer with a first

Filtering means before a second filter means after the sample makes it possible to visualize wavelength shifts 400 by various physical or chemical effects of the light 304 irradiated and emitted onto a sample.

If a sample which simultaneously fluoresces and scatters or diffusely reflects, irradiated with light can be easily distinguished with the system presented here between the wavelength-shifted and non-wavelength-shifted reflected / scattered / transmitted / reflected light. This substantially extends the application possibilities of the spectrometer. For this purpose, the spectrometer system has two filter elements in order to be able to distinguish between non-shifted and (anti) Stokes-shifted light.

Thus, with the system presented here, the proportion of the light scattered scattered at a wavelength other than the irradiated wavelength can be quantitatively discriminated from that reflected at the same wavelength. 5 shows a representation of different harmonics 500, 502, 504, 506. The harmonics are shown in a diagram which has plotted on its abscissa a decreasing wavelength or an increasing frequency. On the ordinate an intensity is offered. The

Harmonics 502, 504, 506 are the higher order harmonics of

Fundamental wavelength 500.

The filter devices shown in Fig. 2 can be designed as a Fabry-Perot interferometer. Then, a gap width between two reflective surfaces of the interferometer determines the fundamental wavelength 500. The fundamental wavelength 500 corresponds to the resonant frequency corresponding to the gap width. Light with the resonance frequency respectively

Fundamental wavelength 500, the interferometer may pass substantially unattenuated. Other frequencies are attenuated and out of the light

filtered out. The harmonics 502, 504, 506 each have an integer multiple frequency of the resonance frequency and can also the

Interferometer happen because they are also resonant at the gap width of the fundamental wavelength 500.

In the approach presented here, at both interferometers

different fundamental wavelengths are set. If the first

Filter set to the fundamental wavelength 500, the sample is also irradiated with the wavelengths of the harmonics 502, 504, 506. The second filter device can be set, for example, to the first harmonic 502 as the fundamental wavelength. Then be at the second

Filter device, the fundamental wavelength 500 and the second harmonic 504 filtered out. The third harmonic 506 may pass through the second filter device again because the third harmonic 506 is also the first harmonic of the gap width of the second filter device.

By using the FPI filter elements before and after the sample, specifically disturbing, in particular higher orders 504 can be filtered out. One FPI can do this with twice the slit width of the other FPI operate. So every second order can be filtered out and the usable wavelength range can be significantly extended.

Fig. 6 shows a representation of a temporal change of a first

Wavelength range 112 according to an embodiment. The change is plotted on a graph, on its abscissa the time and on its ordinate an ascending frequency or decreasing

Wavelength has applied. With an FPI will be the desired

Wavelength range set, which is shown in Fig. 6 by the curve with the plateaus 600, 602, 604 and 606. The other FPI is preferably resonant between the desired wavelength range and a

Wavelength range 608 next to it (small amplitude over the respective

Plateaus 600, 602, 604, 606) in which the first FPI no longer transmits, modulates back and forth. In this way, on / off modulation of the light source can be made e.g. be achieved for the lock-in detection. This is a different application than previously described, but this mode of operation does not work with fluorescent or phosphorescent samples.

The approach presented here can be used in lock-in detection. By a rapid modulation of the integrated with the light source first filter device with a small amplitude, the transmitted

Light signal 112 in the passage area 608 of the second filter device integrated with the detector in and out. This periodic signal change is then used for lock-in detection, which dramatically improves the signal-to-noise ratio of the measurement signal. Also, such a disturbing background signal can be eliminated. For this purpose, it may be favorable to design the fast-modulated filter device so that the fast portion of the modulation can be resonant.

In other words, FIG. 6 shows a sketch of how the resonator lengths of the two filter devices can be set for lock-in detection, wherein a y-scale of the two resonator lengths is not necessarily identical.

According to a further embodiment, the approach presented here for the fresh determination of pork can be used. If Pork with blue / UV light z. B., a wavelength of about 410 nm) is irradiated, depending on the freshness of a varying proportion

fluorescent light in a wavelength range of about 500 to 600 nm. With broadband lighting and detection can only with

Filter elements before and after the sample, the proportion of fluorescent light and thus the freshness of the pork meat can be accurately measured / detected.

FIG. 7 shows a flow chart of a method 700 for operating a microspectrometer according to one exemplary embodiment. The method 700 may be performed on a microspectrometer as in FIG. 2. The method 700 includes a step 702 of providing a step 704 of FIG

Passing and a step 706 of detecting. In step 702 of providing, light is provided using a lighting device. The light is broadband, so has a spectrum with a large frequency range. In step 704 of passing, a first one is selectable using a first filter means

Wavelength range of light transmitted to a sample. Further, in step 704 of passing using a second filter means, a second selectable wavelength range from the sample to a

Detector device passed. In step 706 of detecting, an intensity of the transmitted light from the sample is detected in an intensity value. In one embodiment, first, the wavelengths transmitted by the first and second FPI filter systems are set equal and a wavelength scan is performed. Then, for each wavelength set at the first filter system, the second filter system is scanned. Thus, the wavelength shifted components can be determined and subtracted from the first acquired measurement data. By using algorithms, such as Hadamard matrices, the measurement time can be reduced.

If an exemplary embodiment comprises a "and / or" link between a first feature and a second feature, then this is to be read so that the embodiment according to one embodiment is both the first feature as well as the second feature and according to another embodiment, either only the first feature or only the second feature.

Claims

claims

A microspectrometer (100) comprising: illumination means (102) for providing light (110), the illumination means (102) being aligned with a sample location (106) for a sample (114) of the microspectrometer (100); a first tunable filter device (104) for passing a first selectable wavelength range (112) of the light (110) from the illumination device (102) to the sample location (106); a detector means (108) for detecting an intensity of the light (116), the detector means (108) being aligned with the sample location (106); and second tunable filter means (200) for passing a second selectable wavelength range (608) of the light (116) from the sample location (106) to the detector means (108).

2. A microspectrometer (100) according to claim 1, wherein the

Lighting device (102) and the detector device (108) are arranged in a transmission geometry on opposite sides of the sample location (106).

3. Microspectrometer (100) according to one of the preceding

Claims in which the illumination device (102) and the

Detector device (108) are aligned in a reflection geometry at an angle to each other on the sample location (106).

4. Microspectrometer (100) according to one of the preceding

Claims in which the first filter device (104) and the Lighting device (102) are combined to form a lighting unit (202) and / or the second filter device (200) and the detector device (108) to a detector unit (204)

are summarized.

Microspectrometer (100) according to one of the preceding

Claims in which the first filter device (104) comprises at least one first Fabry-Perot filter and / or the second filter device (200) comprises at least one second Fabry-Perot filter, in particular wherein the first and / or second Fabry-Perot filter Filter tuned designed.

Microspectrometer (100) with a control device according to claim 12.

A method (700) of operating a microspectrometer (100) according to any one of the preceding claims, wherein the method (700) comprises the steps of:

Providing (702) light (110);

Passing (704) a first selectable wavelength range (112) of the light (110) to a sample (114);

Passing (704) a second selectable wavelength range (806) from the sample (114); and

Detecting (706) an intensity of the light (116) from the sample (114).

The method (700) of claim 7, wherein in step (704) of passing the first wavelength range (112) and / or the second wavelength range (806) is temporally varied, wherein in step (706) of detecting a temporal spectrum of the light ( 116) is recorded by the sample (114). A method (700) according to any one of the preceding claims, wherein in said step (704) of passing said second wavelength range (806) is varied while maintaining said first wavelength range (112) constant or at which said first wavelength range (112) is varied. while the second wavelength range (806) is held constant, or wherein in step (704) of transmitting, the first (112) and second (806) wavelength ranges are varied.

The method (700) of any one of the preceding claims, wherein in step (704) of passing, the first wavelength region (112) and the second wavelength region (806) are tuned to different harmonics (500, 502, 504, 506).

The method (700) of any of the preceding claims, wherein the first and second tunable filter means (104, 200) are set to pass the same wavelength range of light, wherein one of the tunable filter means (104, 200) is modulated.

A controller (206) arranged to execute steps of the method (700) according to any one of the preceding claims in respective units.

A computer program adapted to perform the method (700) of any one of the preceding claims.

A machine readable storage medium storing the computer program of claim 13.