SPECTROMETER AND A METHOD FOR CONTROLLING THE SPECTROMETER

• US 20100097613A1
• Filed: 01/23/2008
• Published: 04/22/2010
• Est. Priority Date: 01/26/2007
• Status: Active Grant

• Current Assignee: Valtion Teknillinen Tutkimuskeskus
• Original Assignee: Valtion Teknillinen Tutkimuskeskus
• Inventors: Saari, Heikki
• Granted Patent: US 8,233,147 B2
• Time in Patent Office: Days
• US Class Current: 356/454
• CPC Class Codes: G01J 3/10 Arrangements of light sources specially adapted for spectrometry or colorimetry
• CPC Class Codes: G01J 3/26 using multiple reflection, e.g. Fabry-Perot interferometer, variable interference filters
• CPC Class Codes: G01J 3/433 Modulation spectrometry; Derivative spectrometry
• CPC Class Codes: G02B 26/001 based on interference in an adjustable optical cavity interference filters G02B5/28; devices or arrangements using multiple reflections in spectrometry or monochromators G01J3/26

Abstract

The invention relates to a spectrometer for material analysis and to a control method for a spectrometer. The spectrometer includes a radiant source (140) formed by multiple single radiation sources (141) having different central wavelengths, for generating a measuring signal, a measurement object (100) containing a material to be analyzed, at least one electrically tunable Fabry-Perot filter (120, 220) for the band pass filtering the measuring signal by at least two pass bands, and a detector (300, 400) for detecting said filtered measuring signals received from the measurement object (100). In accordance with the invention the spectrometer has means (312) for modulating each of the single radiation sources (141) and correspondingly means (307, 309) for demodulating the detected signals such that the signal from each single radiation source can be distinguished from each other in the detector (300, 400), and the spectrometer has means for detecting (300, 400) and demodulating (306, 307) multiple pass bands simultaneously.

Claims

1. A spectrometer for material analysis comprising:

a radiant source (140) formed by multiple single radiation sources (141) having different central wavelengths, for generating a measuring signal,

a measurement object (100) containing a material to be analyzed,

at least one electrically tunable Fabry-Perot filter (120, 220) for the band pass filtering the measuring signal by at least two pass bands for the used signal wavelength range, and

a detector (300, 400) for detecting said filtered measuring signals received from the measurement object (100),

wherein

the spectrometer has means (312) for modulating each of the single radiation sources (141) and correspondingly means (307, 309) for demodulating the detected signals such that the signal from each single radiation source can be distinguished from each other in the detector (300, 400), and

the spectrometer has means for detecting (300, 400) and demodulating (306, 307) multiple pass bands simultaneously.

2. The spectrometer in accordance with claim 1, wherein the means for modulating and demodulating are based on frequency modulation.

3. The spectrometer in accordance with claim 1, wherein the means for modulating and demodulating are based on time division modulation.

4. The spectrometer in accordance with claim 1, wherein the means for modulating and demodulating are based on phase modulation.

5. The spectrometer in accordance with claim 1, wherein the spectrometer includes a second Fabry-Perot interferometer (220) in vicinity of the detector (300, 400).

6. The spectrometer in accordance with claim 1, wherein the multiple single radiation sources (141) are LEDs.

13. The spectrometer in accordance with claim 1, wherein a second Fabry-Perot interferometer (220) is used in vicinity of the detector (300, 400).

14. The spectrometer in accordance with claim 1, wherein the signal is formed by the multiple single LED radiation sources (141).

7. A control method for a spectrometer for material analysis, which method comprises the following steps:

generating a measurement signal is by a radiant source (140) formed by multiple single radiation sources (141) having different central wavelengths, for generating a measuring signal,

directing the measurement signal to a measurement object (100) containing a material to be analyzed,

filtering the measurement signal by at least one electrically tunable Fabry-Perot filter (120, 220) by at least two pass bands for the used signal wavelength range, and

detecting (300, 400) said filtered measuring signals received from the measurement object (100),

wherein the method further comprises

modulating (312) each of the single radiation sources (141) and correspondingly

demodulating (307, 309) the detected signals such that the signal from each single radiation source can be distinguished from each other in the detector (300, 400) and

detecting (300, 400) and demodulating (306, 307) multiple pass bands simultaneously.

8. The method in accordance with claim 7, wherein the modulation and demodulation are performed by frequency modulation.

9. The method in accordance with claim 7, wherein the modulation and demodulation are performed by time division modulation.

10. The method in accordance with claim 7, wherein the modulation and demodulation are performed by phase modulation.

11. The method in accordance with claim 7, wherein a second Fabry-Perot interferometer (220) is used in vicinity of the detector (300, 400).

12. The method in accordance with claim 7, wherein the signal is formed by the multiple single LED radiation sources (141).