Radiation filter, spectrometer and imager using a micro-mirror array

• US 6,046,808 A
• Filed: 04/09/1999
• Issued: 04/04/2000
• Est. Priority Date: 04/09/1999
• Status: Expired due to Term

• Current Assignee: Plain Sight Systems Incorporated (Water Intelligence Plc)
• Original Assignee: Three LC Incorporated
• Inventors: Fateley, William G.
• Primary Examiner(s): Evans, F. L.
• Application Number:
  US09/289,482
• Time in Patent Office: 361 Days
• Field of Search: 356/310, 356/326, 356/328, 356/330
• US Class Current: 356/330
• CPC Class Codes: G01J 2003/2866 Markers; Calibrating of scan
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/0218 using optical fibers
• CPC Class Codes: G01J 3/0229 using masks, aperture plates, spatial light modulators or spatial filters, e.g. reflective filters
• CPC Class Codes: G01J 3/027 Control of working procedures of a spectrometer; Failure detection; Bandwidth calculation
• CPC Class Codes: G01J 3/06 Scanning arrangements arrangements for order-selection
• CPC Class Codes: G01J 3/18 using diffraction elements, e.g. grating gratings per se G02B
• CPC Class Codes: G01J 3/2823 Imaging spectrometer
• CPC Class Codes: G01J 3/2889 Rapid scan spectrometers; Time resolved spectrometry

Abstract

A spectrometer (10) includes a two-dimensional array of modulatable micro-mirrors (18), a detector (20), and an analyzer (22). The array of micro-mirrors is positioned for receiving individual radiation components forming a part of an input radiation source. The micro-mirrors are modulated at different modulation rates in order to reflect individual radiation components therefrom at known and different modulation rates. The micro-mirror array combines a number of the reflected individual radiation components and reflects the combined components to the detector. The detector is oriented to receive the combined radiation components reflected from the array and is operable to create an output signal representative thereof. The analyzer is operably coupled with the detector to receive the output signal and to analyze at least some of the individual radiation components making up the combined reflection. By using a micro-mirror that receives individual radiation components and then modulates the radiation components at different rates, all of the radiation components can be focused onto a single detector to maximize the signal-to-noise ratio of the detector. A variable band pass filter spectrometer, variable band reject filter spectrometer, variable multiple band pass filter spectrometer, and a variable multiple band reject filter spectrometer utilizing the same invention are also disclosed.

Claims

1. An analysis assembly for analyzing the absorption or attenuation by a sample of input radiation having a plurality of individual radiation components, said assembly comprising:

a two-dimensional array of modulatable micro-mirrors located for receiving individual radiation components forming a part of said input radiation, said micro-mirrors being modulatable at different modulation rates in order to reflect individual radiation components therefrom at known and different modulation rates and for combining a number of the reflected individual radiation components to generate a combined reflection;

a detector oriented to receive said combined reflection from said array, and operable to create an output signal representative of said combined number of individual radiation components; and

an analyzer operably coupled with said detector to receive said output signal, and providing an individual analyses of at least some of said individual radiation components making up said combined reflection.

2. The assembly of claim 1, said analyzer comprising a computer operably coupled with said detector and array for controlling the modulation of said micro-mirrors and for providing said individual analyses.

3. The assembly of claim 1, further including a reflector positioned between the detector and the array and operable to receive said combined reflection from said array and to focus the combined reflection on said detector.

4. The assembly of claim 1, said analyzer operable to perform a Fourier analysis upon said output.

5. The assembly of claim 1, said individual analyses comprising the energy magnitude of said individual radiation components.

6. The assembly of claim 1, said input radiation being electromagnetic radiation.

7. The assembly of claim 1, said individual radiation components comprising different, substantially constant wavelength radiation components.

8. The assembly of claim 1, said individual radiation components comprising spatial resolution components derived from an image.

9. Apparatus comprising:

an assembly operable to generate input radiation having a plurality of individual radiation components;

a two-dimensional array of modulatable micro-mirrors located for receiving individual radiation components forming a part of said input radiation, said micro-mirrors being modulatable at different modulation rates in order to reflect individual radiation components therefrom at known and different modulation rates and with micro-mirror orientations for combining a number of the reflected individual radiation components to generate a combined reflection;

a detector oriented to receive said combined reflection from said array, and operable to create an output signal representative of said combined number of individual radiation components; and

an analyzer operably coupled with said detector to receive said output signal, and providing an individual analyses of at least some of said individual radiation components making up said combined reflection.

10. The assembly of claim 9, said analyzer comprising a computer operably coupled with said detector and array for controlling the modulation of said micro-mirrors and for providing said individual analyses.

11. The assembly of claim 9, further including a reflector positioned between the detector and the array and operable to receive said combined reflection from said array and to focus the combined reflection on said detector.

12. The assembly of claim 9, said analyzer operable to perform a mathematical manipulation upon said output.

13. The assembly of claim 9, said individual analyses comprising the energy magnitude of said individual radiation components.

14. The assembly of claim 9, said input radiation being infrared radiation.

15. The assembly of claim 9, said individual radiation components comprising different, substantially constant wavelength radiation components.

16. The assembly of claim 9, said individual radiation components comprising spatial resolution components derived from an image.

17. An analysis assembly for analyzing the absorption or attenuation by a sample of input radiation having a plurality of individual radiation components, said assembly comprising:

a two-dimensional array of modulatable devices located for receiving individual radiation components forming a part of said input radiation, said devices being modulatable at different modulation rates in order to project individual radiation components therefrom at known and different modulation rates for combining a number of the projected individual radiation components to generate a combined projection;

a detector oriented to receive said combined projection from said array, and operable to create an output representative of said combined number of individual radiation components; and

an analyzer operably coupled with said detector to receive said output, and providing an individual analyses of at least some of said individual radiation components making up said combined projection.

18. The analysis assembly of claim 17, wherein said assembly is operable for use as a variable filter.