Methods and systems for distinguishing multiple wavelengths of radiation in a detection system

• US 20040104346A1
• Filed: 11/06/2003
• Published: 06/03/2004
• Est. Priority Date: 11/08/2002
• Status: Active Grant

• Current Assignee: L3harris Cincinnati Electronics Corporation (L3Harris Technologies, Inc.)
• Original Assignee: L-3 Communications Cincinnati Electronics Corporation (L3Harris Technologies, Inc.)
• Inventors: Voelker, Jeffrey J., Greiner, Mark E., Garter, Michael J., Devitt, John W., Wade, David R.
• Granted Patent: US 7,351,977 B2
• Time in Patent Office: Days
• US Class Current: 250/339.14
• CPC Class Codes: G01J 3/0259 Monolithic
• CPC Class Codes: G01J 3/2803 using photoelectric array detector
• CPC Class Codes: G01J 3/2823 Imaging spectrometer
• CPC Class Codes: G01J 3/36 Investigating two or more bands of a spectrum by separate detectors
• CPC Class Codes: G01J 5/602 using selective, monochromatic or bandpass filtering
• CPC Class Codes: G02B 27/1013 for colour or multispectral image sensors, e.g. splitting an image into monochromatic image components on respective sensors spectral imaging systems G01J
• CPC Class Codes: G02B 27/1086 operating by diffraction only
• CPC Class Codes: G02B 27/126 The splitting element being a prism or prismatic array, including systems based on total internal reflection

Abstract

Methods and systems for detection of multiple wavelengths of radiation are provided. In accordance with one embodiment, a method is provided for detecting multiple wavelengths of light received within a predetermined wavelength range. The method comprises receiving light of a predetermined wavelength range from a source, and splitting the received light into multiple components having differing wavelengths. The method further comprises directing the components toward individual locations spaced from one another. In addition, this embodiment comprises detecting at least some of the components at the locations.

Claims

1. A infrared imaging system for providing images of a scene comprising:

a focal plane array having a detection surface comprising a plurality of pixels, each pixel having first and second detectors located adjacent to each other upon the detection surface, wherein the first and second detectors are configured to detect the presence of infrared light; and

a dispersive optic positioned along a center portion of each pixel and configured to receive infrared light from a scene, separate the light between a first wavelength range and a second wavelength range, and transmit substantially all of the light in the first wavelength range toward the first detector for the pixel and substantially all of the light in the second wavelength range toward the second detector for the pixel .

2. The system as recited in claim 1, wherein the dispersive optic comprises a prism.

3. The system as recited in claim 1, wherein the dispersive optic comprises a diffraction grating.

4. A focal plane array for providing real-time images of scenes, comprising:

a plurality of first detectors provided along a two-dimensional image facing plane of the array, wherein each first detector is provided at a pixel location and is configured and positioned to detect the presence of light within a first region of the infrared wavelength band; and

a plurality of second detectors provided along the image facing plane, wherein each second detector is provided at a pixel location and adjacent a corresponding first detector for that pixel location, and wherein each second detector is configured and positioned to detect the presence of light within a second region of the infrared wavelength band.

5. The array as recited in claim 4, wherein the detectors comprise spaced semiconductor diodes having an electrical property affected by optical energy incident thereon and including a junction separating first and second differently doped regions.

6. The array as recited in claim 4, wherein the first detector comprises a material sensitive to the presence of light within the first region of the infrared wavelength band and the second detector comprises a different material sensitive to the presence of light within the second region of the infrared wavelength band.

7. The array as recited in claim 4, wherein the first detector includes a filter that passes light within the first region of the infrared wavelength band and the second detector includes a filter that passes light within the second region of the infrared wavelength band.

8. An imaging system for providing an image representation of a scene, comprising:

a plurality of detection locations arranged into a two-dimensional array, wherein each detection location includes a first detector and a second detector positioned adjacent to each other; and

an optical element associated with each detection location and configured to receive light, separate the light into first and second wavelength ranges, and focus the light in the first range toward the first detector of the detection location and the light in the second range toward the second detector of the detection location, wherein the optical element does not comprise a lens.

9. The system as recited in claim 8, wherein the wavelength ranges comprise at least a portion of the infrared wavelength band.

10. The system as recited in claim 8, wherein the detectors are positioned along the two-dimensional array

11. The system as recited in claim 8, wherein the optical element comprises a prism.

12. The system as recited in claim 8, wherein the optical element comprises a grating.

13. The system as recited in claim 8, wherein the optical element comprises a piezoelectric material.

14. The system as recited in claim 8, wherein the optical element does not converge or diverge the light.

15. A method for providing multi-wavelength images from light from a, the method comprising:

receiving light of a predetermined wavelength range from a scene;

splitting the received light into a first component having a first wavelength range and a second component having a second wavelength range;

directing the first component in a first direction toward a first location and directing the second component in a second direction toward a second location, wherein the first and second locations are spaced from one another;

transmitting the first and second components through at least one light guide toward first and second locations;

detecting the first component at the first location; and

detecting the second component at the second location.

16. The method as recited in claim 15, wherein the predetermined wavelength range comprises at least a portion of the infrared range.

17. The method as recited in claim 15, further comprising:

indicating the detection of the first component on a display using a first color; and

indicating the detection of the second component on the display using a second color.

18. The method as recited in claim 15 wherein the splitting and directing operations are conducted simultaneously.

19. The method as recited in claim 18, wherein the splitting and direction operations are conducted by a prism.

20. The method as recited in claim 15, wherein the operations are conducted simultaneously and repetitively at the various pixels in an infrared imaging system.

21. The method as recited in claim 15, wherein the light guide comprises a silicon light pipe.

22. A system for constructing a real-time scene imaging system, the method comprising:

determining a pixel size for the system based upon components to be used in the system;

providing a pair of sensors within the pixel size, the sensors being spaced horizontally from one another within an image facing plane, the sensors being configured to detect radiation in different wavelength bands; and

providing an optic to receive radiation from a scene, wherein the optic is configured to receive radiation from the scene and transmit a first wavelength range of the radiation toward one of the sensors and a second wavelength range of the radiation toward the other sensor.

23. The method as recited in claim 22, wherein the sensors are configured to detect radiation in a different wavelength band by comprising materials of differing wavelength sensitivity.

24. The method as recited in claim 22, wherein the sensors are configured to detect radiation in a different wavelength band by including filters which pass radiation of different wavelength bands.

25. An imaging system for providing a real-time image representation of a scene, comprising:

a plurality of detection locations arranged into a two-dimensional array, wherein each detection location includes a first detector and a second detector positioned adjacent to each other;

an optical element associated with each detection location and configured to receive light, separate the light into first and second wavelength ranges, and focus the light in the first range toward the first detector of the detection location and the light in the second range toward the second detector of the detection location, so that the detectors at the detection locations provide a real-time multi-wavelength representation of at least a portion of a scene; and

at least one light directing element associated with each detection location and configured to direct the light toward the detectors.

26. The system as recited in claim 25, wherein the optical element comprises a prism.

27. The system as recited in claim 25, wherein the light directing element comprises at least one of a light pipe and reflective wall.

28. The system as recited in claim 25, wherein the at least one light directing element comprises a light pipe configured between the detectors and the optical element, and a sidewall positioned adjacent the light pipe.

29. The system as recited in claim 25, wherein the optical element is a non-lens component.