Abstract
A spectrometer includes an emitter that is configured to emit electromagnetic radiation, a sample area that is arranged at an outer face of the spectrometer, a modulation unit including an electrochromic material, an optical filter, an optical detector, an integrated circuit that has a main plane of extension, and an optical path for electromagnetic radiation emitted by the emitter towards the optical detector via the sample area, the modulation unit and the optical filter, wherein the electrochromic material is electrically connected with the integrated circuit, and the modulation unit is configured to modulate electromagnetic radiation temporally. Furthermore, a method for detecting electromagnetic radiation is provided.
Claims
1. A spectrometer comprising: an emitter that is configured to emit electromagnetic radiation, a sample area that is arranged at an outer face of the spectrometer, a modulation unit comprising an electrochromic material, an optical filter, an optical detector, an integrated circuit that has a main plane of extension, and an optical path for electromagnetic radiation emitted by the emitter towards the optical detector via the sample area, the modulation unit and the optical filter, wherein the electrochromic material is electrically connected with the integrated circuit, and the modulation unit is configured to modulate electromagnetic radiation temporally.
2. The spectrometer according to claim 1, wherein the optical filter is configured to transmit electromagnetic radiation modulated by the modulation unit.
3. The spectrometer according to claim 1, wherein the integrated circuit comprises a lock-in detection function.
4. The spectrometer according to claim 1, wherein the optical detector is configured to detect electromagnetic radiation in the visible and in the infrared range.
5. The spectrometer according to claim 1, wherein the optical detector is a photon detector or a thermal detector.
6. The spectrometer according to claim 1, wherein a further optical detector is arranged adjacent to the emitter.
7. The spectrometer according to claim 1, wherein the emitter, the modulation unit, the optical filter, the optical detector and the integrated circuit are arranged on the same side of the sample area.
8. The spectrometer according to claim 1, wherein the modulation unit is arranged between the emitter and the sample area in a vertical direction that is perpendicular to the main plane of extension of the integrated circuit.
9. The spectrometer according to claim 1, wherein a transmission region is arranged between the sample area and the emitter in a vertical direction that is perpendicular to the main plane of extension of the integrated circuit, wherein the transmission region has a transmissivity of at least 0.7 for electromagnetic radiation emitted by the emitter.
10. The spectrometer according to claim 1, wherein the sample area is arranged between the emitter (11) and the optical detector in a vertical direction, and the sample area is arranged adjacent to an opening within the spectrometer, wherein the vertical direction is perpendicular to the main plane of extension of the integrated circuit.
11. The spectrometer according to claim 1, wherein the optical filter is arranged between the modulation unit and the optical detector in a vertical direction that is perpendicular to the main plane of extension of the integrated circuit.
12. The spectrometer according to claim 1, wherein the modulation unit is arranged between the optical filter and the optical detector in a vertical direction that is perpendicular to the main plane of extension of the integrated circuit.
13. The spectrometer according to claim 1, wherein the integrated circuit is configured to control a frequency of a voltage that is applied to the electrochromic material.
14. The spectrometer according to claim 1, wherein an intensity of the electromagnetic radiation passing the modulation unit is modulated.
15. A portable device for use on the consumer electronics market, the portable device comprising the spectrometer according to claim 1, wherein the portable device is in particular a mobile phone, a wearable or a laptop computer.
16. A method for detecting electromagnetic radiation, the method comprising: emitting electromagnetic radiation by an emitter, directing the emitted electromagnetic radiation to a sample area, placing sample matter on or above the sample area, temporally modulating electromagnetic radiation emitted by the emitter in a modulation unit comprising an electrochromic material, transmitting electromagnetic radiation within a predefined wavelength range by an optical filter, and detecting electromagnetic radiation transmitted by the optical filter by an optical detector, wherein the modulation of the modulation unit is controlled by an integrated circuit.
17. The method according to claim 16, wherein electromagnetic radiation emitted by the emitter is modulated before passing the optical filter, and the optical filter is configured to transmit the modulated electromagnetic radiation.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0042] The following description of figures may further illustrate and explain exemplary embodiments. Components that are functionally identical or have an identical effect are denoted by identical references. Identical or effectively identical components might be described only with respect to the figures where they occur first. Their description is not necessarily repeated in successive figures.
[0043] FIGS. 1A, 1B, 1C, 1D and 1E show exemplary embodiments of the spectrometer.
[0044] FIGS. 2A, 2B, 2C, 2D and 2E show further exemplary embodiments of the spectrometer.
[0045] FIG. 3 shows a cross-section through an exemplary embodiment of the spectrometer.
[0046] FIG. 4 shows an exemplary embodiment of the modulation unit.
[0047] FIG. 5 shows a simulated transmission through the modulation unit.
[0048] FIG. 6 shows another exemplary embodiment of the modulation unit.
[0049] FIG. 7 shows an exemplary embodiment of a portable device.
DETAILED DESCRIPTION
[0050] In FIG. 1A an exemplary embodiment of a spectrometer 10 is shown. The spectrometer 10 comprises an emitter 11 that is configured to emit electromagnetic radiation. The emitter 11 is arranged adjacent to a sample area 12 that is arranged at an outer face 13 of the spectrometer 10. The sample area 12 is arranged adjacent to an opening 22 within the spectrometer 10. The opening 22 can extend completely through the spectrometer 10. The opening 22 is arranged between the emitter 11 and a modulation unit 14. This means, the opening 22 is a channel between the emitter 11 and the modulation unit 14. The sample area 12 is located at the outer surface of the spectrometer 10 within the opening 22. Within the opening 22 the outer surfaces of the spectrometer 10 are in direct contact with the environment of the spectrometer 10. The opening 22 can be configured in such a way that gases from the environment of the spectrometer 10 can penetrate the opening 22.
[0051] The modulation unit 14 comprises an electrochromic material. Furthermore, the modulation unit 14 is configured to modulate electromagnetic radiation temporally. The spectrometer 10 further comprises an optical filter 15 on which the modulation unit 14 is arranged. The optical filter 15 is arranged on an optical detector 16. The optical filter 15 is configured to transmit electromagnetic radiation modulated by the modulation unit 14. Moreover, the optical detector 16 is configured to detect electromagnetic radiation in the visible and in the infrared range. The optical detector 16 can be a photon detector or a thermal detector. The optical detector 16 is arranged on an integrated circuit 17 that has a main plane of extension and that comprises a lock-in detection function. The electrochromic material of the modulation unit 14 is electrically connected with the integrated circuit 17. In this way, the integrated circuit 17 can control the modulation frequency.
[0052] In this configuration there exists an optical path for electromagnetic radiation emitted by the emitter 11 towards the optical detector 16 via the sample area 12, the modulation unit 14 and the optical filter 15.
[0053] In a vertical direction z that is perpendicular to the main plane of extension of the integrated circuit 17 the sample area 12 is arranged between the emitter 11 and the optical detector 16. The optical filter 15 is arranged between the modulation unit 14 and the optical detector 16 in the vertical direction z. The opening 22 extends through the spectrometer 10 in a lateral direction x which is parallel to the main plane of extension of the integrated circuit 17.
[0054] Optionally, a further optical detector 18 is arranged adjacent to the emitter 11. Since the further optical detector 18 is optional, it is separated from the emitter 11 only by a dashed line. The further optical detector 18 is configured to detect electromagnetic radiation emitted by the emitter 11 and reflected at sample matter within the opening 22 or at the modulation unit 14. In this way, the temperature drift of the emitter 11 can be determined and calibrated which enables a more reproducible and more reliable measurement of the spectrometer 10. The embodiment shown in FIG. 1A is particularly suitable for monitoring the temperature drift of the emitter 11.
[0055] The spectrometer 10 described herein can be employed in a method for detecting electromagnetic radiation. The method comprises emitting electromagnetic radiation by the emitter 11. The emitted electromagnetic radiation is directed to the sample area 12. In FIG. 1A the emitter 11 mainly emits electromagnetic radiation in the direction of the sample area 12. On or above the sample area 12, sample matter is placed. The sample matter can be a solid, a liquid or a gas. The embodiment shown in FIG. 1A is most suitable for gases as they can easily reach the opening 22. Afterwards, the electromagnetic radiation emitted by the emitter 11 and transmitted by the sample matter is temporally modulated in the modulation unit 14. The optical filter 15 transmits electromagnetic radiation within a predefined wavelength range. Furthermore, the optical filter 15 is configured to transmit the modulated electromagnetic radiation. Subsequently, the electromagnetic radiation transmitted by the optical filter 15 is detected by the optical detector 16. The optical detector 16 converts the electromagnetic radiation reaching the optical detector 16 into a modulated voltage signal. This voltage signal is amplified by the integrated circuit 17. From the voltage signal it can be determined how the intensity of the electromagnetic radiation transmitted by the sample matter is changed by the sample matter. In this way, properties of the sample matter can be determined.
[0056] FIG. 1B shows another exemplary embodiment of the spectrometer 10. The setup is different from the setup of FIG. 1A in that the modulation unit 14 and the optical filter 15 are arranged above the sample area 12. This means, the modulation unit 14 is arranged between the emitter 11 and the optical filter 15 in the vertical direction z. The optical filter 15 is arranged between the sample area 12 and the modulation unit 14 in the vertical direction z.
[0057] FIG. 1C shows another exemplary embodiment of the spectrometer 10. The setup is different from the setup of FIG. 1A in that the modulation unit 14 is arranged between the emitter 11 and the sample area 12 in the vertical direction z. The sample area 12 is arranged between the modulation unit 14 and the optical filter 15 in the vertical direction z.
[0058] FIG. 1D shows another exemplary embodiment of the spectrometer 10. The setup is different from the setup of FIG. 1B in that the positions of the modulation unit 14 and the optical filter 15 are exchanged. This means, the optical filter 15 is arranged between the emitter 11 and the modulation unit 14 in the vertical direction z. The modulation unit 14 is arranged between the optical filter 15 and the sample area 12 in the vertical direction z.
[0059] FIG. 1E shows another exemplary embodiment of the spectrometer 10. The setup is different from the setup of FIG. 1A in that the positions of the optical filter 15 and the modulation unit 14 are exchanged. This means, the optical filter 15 is arranged between the sample area 12 and the modulation unit 14 in the vertical direction z. The modulation unit 14 is arranged between the optical filter 15 and the optical detector 16 in the vertical direction z.
[0060] The embodiments shown in FIGS. 1A, 1B, 1C, 1D and 1E are different possibilities for arranging the parts of the spectrometer 10 on top of each other. Some or all parts of the spectrometer 10 can be monolithically integrated. This means, some or all parts of the spectrometer 10 can be grown directly on top of each other.
[0061] FIGS. 2A, 2B, 2C, 2D and 2E show another set of exemplary embodiments of the spectrometer 10. These arrangements differ from the embodiments shown in the previous figures in that the sample area 12 is arranged at a top side 19 of the spectrometer 10. This means, the emitter 11, the modulation unit 14, the optical filter 15, the optical detector 16 and the integrated circuit 17 are arranged on the same side of the sample area 12.
[0062] FIG. 2A shows another exemplary embodiment of the spectrometer 10. On the integrated circuit 17 the emitter 11 is arranged. Optionally, the further optical detector 18 is arranged adjacent to the emitter 11 on the integrated circuit 17. In a lateral direction x next to the emitter 11 the optical detector 16 is arranged on the integrated circuit 17, where the lateral direction x extends parallel to the main plane of extension of the integrated circuit 17. On the optical detector 16 the optical filter 15 is arranged. On the optical filter 15 the modulation unit 14 is arranged. On the emitter 11, the further optical detector 18 and the modulation unit 14 a transmission region 21 is arranged. The transmission region 21 has a transmissivity of at least 0.7 for electromagnetic radiation emitted by the emitter 11. On top of the transmission region 21 the sample area 12 is arranged. This means, the sample area 12 is arranged at a top side 19 of the spectrometer 10. The top side 19 of the spectrometer 10 forms an outer face 13. The sample matter can easily be placed on the sample area 12. The embodiments shown in FIGS. 2A to 2E are particularly suitable for all kinds of sample matter. Solids and liquids can be placed on the sample area 12 and gases can be provided in the environment of the spectrometer 10.
[0063] FIG. 2B shows another exemplary embodiment of the spectrometer 10. The setup is different from the setup shown in FIG. 2A in that the modulation unit 14 is arranged on top of the emitter 11. Furthermore, the optical filter 15 is arranged on top of the modulation unit 14. The optical detector 16 is arranged next to the emitter 11, the modulation unit 14 and the optical filter 15 in the lateral direction x.
[0064] FIG. 2C shows another exemplary embodiment of the spectrometer 10. The setup is different from the setup shown in FIG. 2A in that the modulation unit 14 is arranged on top of the emitter 11. The optical filter 15 and the optical detector 16 are arranged next to the emitter 11 and the modulation unit 14 in the lateral direction x.
[0065] FIG. 2D shows another exemplary embodiment of the spectrometer 10. The setup is different from the setup shown in FIG. 2B in that the positions of the modulation unit 14 and the optical filter 15 are exchanged. This means, the emitter 11, the optical filter 15 and the modulation unit 14 are arranged next to the optical detector 16 in the lateral direction x.
[0066] FIG. 2E shows another exemplary embodiment of the spectrometer 10. The setup is different from the setup shown in FIG. 2A in that the positions of the optical filter 15 and the modulation unit 14 are exchanged. This means, the modulation unit 14 is arranged between the optical filter 15 and the optical detector 16 in the vertical direction z.
[0067] FIG. 3 shows a cross section through a further exemplary embodiment of the spectrometer 10. The emitter 11 and the further optical detector 18 are arranged on the integrated circuit 17 next to each other. The modulation unit 14 is arranged above the emitter 11 and the further optical detector 18. Furthermore, the optical detector 16 is arranged on the integrated circuit 17. The optical detector 16 is arranged spaced apart from the further optical detector 18 and the emitter 11. The optical filter 15 is arranged above the optical detector 16. The sample area 12 is arranged above the modulation unit 14 and the optical filter 15. The emitter 11 and the optical detector 16 are arranged in different cavities 20 of the spectrometer 10.
[0068] FIG. 4 shows an exemplary embodiment of the modulation unit 14. The modulation unit 14 comprises a first electrode 27 on which a charge storage layer 25 is arranged. On the charge storage layer 25 an ion conducting layer 24 is arranged. On the ion conducting layer 24 an active layer 26 comprising the electrochromic material is arranged. On the active layer 26 a second electrode 28 in the shape of a grid is arranged. The second electrode 28 can be thin enough so that it has a transmissivity of at least 0.9.
[0069] FIG. 5 shows a simulated transmission through the modulation unit 14. On the x-axis the wavelength is plotted in nanometers. On the y-axis the transmission is plotted in percent. The transmission was simulated for the modulation unit 14 arranged on a Fabry Perot interference filter as the optical filter 15. The optical filter 15 has a peak transmission of 1500 nm. The first and the second electrode 27, 28 are not included in the simulation.
[0070] The continuous line shows the transmission of the optical filter 15 without the modulation unit 14. The dotted line shows the transmission of the optical filter 15 with the modulation unit 14 for the state of maximum transmission of the electrochromic material. The dashed line shows the transmission of the optical filter 15 with the modulation unit 14 for the state of minimum transmission of the electrochromic material. The maximum transmission is slightly reduced by introducing the modulation unit 14. For the state of minimum transmission of the electrochromic material the overall transmission is reduced to below 5%. By switching between the state of maximum transmission and the state of minimum transmission electromagnetic radiation passing the modulation unit 14 is modulated.
[0071] FIG. 6 shows another exemplary embodiment of the modulation unit 14. The modulation unit 14 has the setup as shown in FIG. 4. FIG. 6 shows the arrangement of the modulation unit 14 on top of the integrated circuit 17. The modulation unit 14 is held above the surface of the integrated circuit 17 by a first metal bracket 29 and a second metal bracket 30. The modulation unit 14 is clamped between the metal brackets 29, 30. In this way, the position of the modulation unit 14 is fixed. Via the metal brackets 29, 30 the modulation unit 14 is electrically connected with the integrated circuit 17. The first metal bracket 29 is in electrical contact with the first electrode 27 of the modulation unit 14. An upper part of the first metal bracket 29 comprises an isolation 31 so that the first metal bracket 29 only electrically contacts the first electrode 27. The second metal bracket 30 is in electrical contact with the second electrode 28. A part of the second metal bracket 30 comprises an isolation 31 so that the second metal bracket 30 only electrically contacts the second electrode 28.
[0072] FIG. 7 shows an exemplary embodiment of a portable device 23 for use on the consumer electronics market. The portable device 23 comprises the spectrometer 10. The portable device 23 can be a mobile phone, a wearable or a laptop computer.
