Monolithically configured spectroscopic instrument

Patent metadata

Field	Value
Publication number	US-10732040-B2
Application number	US-201916425685-A
Country	US
Kind code	B2
Filing date	May 29, 2019
Priority date	Jun 1, 2018
Publication date	Aug 4, 2020
Grant date	Aug 4, 2020

Abstract

A spectroscopic instrument includes a first aperture limiting device, a second aperture limiting device, a first mirror, a movable MEMS mirror, and a dispersive element spatially separate from the MEMS mirror, the movable MEMS mirror being movable in relation to the dispersive element, the movable MEMS mirror being monolithically configured as a common component with at least one of the first aperture limiting device, the second aperture limiting device, and the dispersive element, and the first and second aperture limiting devices being arranged to be spatially separate from the movable MEMS mirror and having a lateral offset from a rotational axis of the movable MEMS mirror.

First claim

The invention claimed is:

1. Spectroscopic instrument comprising
a first aperture limiting device, a second aperture limiting device, a first mirror, a movable MEMS mirror, and a dispersive element spatially separate from the MEMS mirror, the movable MEMS mirror being movable in relation to the dispersive element,
the first mirror being configured to influence, in a beam-shaping manner, electromagnetic radiation which enters through the first aperture limiting device, and to direct the influenced radiation to the movable MEMS mirror,
the moveable MEMS mirror being configured to reflect the influenced radiation to the dispersive element,
the dispersive element being configured to spectrally split up the influenced radiation and to reflect it back, within a limited wavelength range, to the moveable MEMS mirror, and the movable MEMS mirror further being configured to reflect the spectrally split-up radiation comprising the limited wavelength range to the first mirror or to a second mirror and from there to the second aperture limiting device,
the movable MEMS mirror being monolithically configured as a common component with at least one of the first aperture limiting device, the second aperture limiting device, and the dispersive element, and the first and second aperture limiting devices being arranged to be spatially separate from the movable MEMS mirror and comprising a lateral offset from a rotational axis of the movable MEMS mirror.

2. Spectroscopic instrument as claimed in claim 1 , wherein the first and second aperture limiting devices each are offset along an offset axis extending orthogonally to the rotational axis of the movable MEMS mirror, the respective offset axis of the respective aperture limiting device extending through the MEMS mirror.

3. Spectroscopic instrument as claimed in claim 1 , wherein the first aperture limiting device and the second aperture limiting device are arranged on a common offset axis.

4. Spectroscopic instrument as claimed in claim 1 , wherein the movable MEMS mirror comprises a contiguous surface area that is free from any aperture limiting devices.

5. Spectroscopic instrument as claimed in claim 1 , wherein the movable MEMS mirror is configured as a plane mirror.

6. Spectroscopic instrument as claimed in claim 1 , wherein the movable MEMS mirror comprises a resonant or quasi-static drive.

7. Spectroscopic instrument as claimed in claim 1 , wherein the movable MEMS mirror is deflectable within a range between ±8° or between ±5° or between ±3°.

8. Spectroscopic instrument as claimed in claim 1 , the spectroscopic instrument further comprising a position sensor for sensing the deflection of the movable MEMS mirror.

9. Spectroscopic instrument as claimed in claim 8 , wherein the position sensor is configured as an optical position sensor comprising a radiation source for emitting electromagnetic radiation and at least one radiation detector for sensing the electromagnetic radiation emitted by the radiation source.

10. Spectroscopic instrument as claimed in claim 9 , wherein the radiation detector comprises at least two radiation-detecting elements.

11. Spectroscopic instrument as claimed in claim 9 , wherein the movable MEMS mirror is configured to at least partly reflect the electromagnetic radiation emitted by the radiation source associated with the position sensor.

12. Spectroscopic instrument as claimed in claim 8 , wherein the position sensor is configured to sense the deflection of the movable MEMS mirror in a time-continuous or time-discrete manner.

13. Spectroscopic instrument as claimed in claim 8 , wherein the position sensor is configured to differentially determine a position of the movable MEMS mirror by forming the difference between a first position sensor signal and a second position sensor signal.

14. Spectroscopic instrument as claimed in claim 1 , the spectroscopic instrument comprising at least one detector for electromagnetic radiation which is arranged behind the second aperture limiting device within the optical path.

15. Spectroscopic instrument as claimed in claim 14 , wherein the detector comprises silicon or a compound of materials from the chemical main groups III or V, or a compound of materials from the chemical main groups II and VI.

16. Spectroscopic instrument as claimed in claim 14 , the spectroscopic instrument comprising a third aperture limiting device and an additional sensor for electromagnetic radiation, the detector for electromagnetic radiation being arranged behind the second aperture limiting device within the optical path, and the additional sensor for electromagnetic radiation being arranged behind the third aperture limiting device within the optical path.

17. Spectroscopic instrument as claimed in claim 16 , wherein the MEMS mirror, the dispersive element, the first aperture limiting device, the second aperture limiting device, and the third aperture limiting device are monolithically configured as a common component.

18. Spectroscopic instrument as claimed in claim 16 , wherein the second aperture limiting device has a first spectral order filter arranged thereat, and wherein the third aperture limiting device has a second spectral order filter arranged thereat, the spectral filter ranges of the first order filter and of the second order filter differing from each other.

19. Spectroscopic instrument as claimed in claim 16 , wherein the detector for electromagnetic radiation comprises silicon, and wherein the additional detector for electromagnetic radiation comprises a compound of materials from the chemical main groups III or V, or a compound of materials from the chemical main groups II and VI, and wherein the additional detector for electromagnetic radiation is configured to detect a spectral range up to an upper cut-off wavelength higher than an upper cut-off wavelength of the detector for electromagnetic radiation.

20. Spectroscopic instrument as claimed in claim 14 , wherein the detector for electromagnetic radiation is configured to sense a spectral range up to an upper cut-off wavelength of 1100 nm, and wherein the additional detector for electromagnetic radiation is configured to detect a spectral range up to an upper cut-off wavelength of 1700 nm or 1900 nm or 2200 nm, or 2500 nm.

21. Spectroscopic instrument as claimed in claim 1 , the spectroscopic instrument being configured to perform a spectral analysis of light within a wavelength range from 780 nm to 2500 nm or from 900 nm to 2200 nm, or from 950 nm to 1900 nm.

22. Spectroscopic instrument as claimed in claim 1 , the spectroscopic instrument comprising a spectral resolution of 10 nm or less.

23. Spectroscopic instrument as claimed in claim 1 , wherein the dispersive element is an optical diffraction grating.

24. Spectroscopic instrument as claimed in claim 23 , wherein the diffraction grating comprises between 150 and 1200 lines per millimeter.

25. Spectroscopic instrument as claimed in claim 1 , wherein the dispersive element is a prism.

26. Spectroscopic instrument as claimed in claim 1 , the spectroscopic instrument comprising dimensions, with regard to a ratio of length×width×height, of 30×20×15 mm 3 or less, or 10×10×6 mm 3 or less, or 10×10×4.5 mm 3 or less.

27. Spectroscopic instrument as claimed in claim 1 , wherein the movable MEMS mirror, the dispersive element as well as the first aperture limiting device and/or the second a

Assignees

• Fraunhofer Ges Forschung

Inventors

• Grueger Heinrich
• Knobbe Jens
• Puegner Tino

Classifications

• G01J3/0291

  Housings; Spectrometer accessories; Spatial arrangement of elements, e.g. folded path arrangements · CPC title

• G01J3/06

  Scanning arrangements {arrangements for order-selection} · CPC title

• G01J3/0229

  using masks, aperture plates, spatial light modulators or spatial filters, e.g. reflective filters · CPC title

• G01J2003/064

  Use of other elements for scan, e.g. mirror, fixed grating · CPC title

• G01J3/14

  using refracting elements, e.g. prisms (G01J3/18, G01J3/26 take precedence {prisms per se G02B5/04}) · CPC title