Integrated filter and detector array for spectral imaging
First Claim
Patent Images
1. A spectral imaging system for detecting the optical spectrum of a target, the system comprising:
- means for receiving an optical signal from the target;
dispersion means for dispersing the optical signal into a spectral signal with component spectra of the optical signal provided along a spectral axis having a frequency range;
detector means aligned with the spectral axis of the spectral signal for receiving and detecting the spectral signal;
the detector means including an optical filter for substantially eliminating stray and background optical signals from detection by the detector means, the optical filter comprising a plurality of bands, the transmission frequency of the bands varying along the detector means, the optical filter being aligned with the spectral axis of the spectral signal, the transmission frequencies of the bands being matched to and aligned with component frequencies of the spectral image; and
the optical filter being directly deposited on the detector means such that the optical filter remains in alignment with the detector means despite temperature changes, shock or vibration.
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Abstract
A spectral imaging system having an integrated filter and photodetector array. The filter has narrow transmission bands which vary in frequency along the photodetector array. The frequency variation of the transmission bands is matched to, and aligned with, the frequency variation of a received spectral image. The filter is deposited directly on the photodetector array by a low temperature deposition process. By depositing the filter directly on the photodetector array, permanent alignment is achieved for all temperatures, spectral crosstalk is substantially eliminated, and a high signal-to-noise ratio is achieved.
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Citations
22 Claims
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1. A spectral imaging system for detecting the optical spectrum of a target, the system comprising:
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means for receiving an optical signal from the target; dispersion means for dispersing the optical signal into a spectral signal with component spectra of the optical signal provided along a spectral axis having a frequency range; detector means aligned with the spectral axis of the spectral signal for receiving and detecting the spectral signal; the detector means including an optical filter for substantially eliminating stray and background optical signals from detection by the detector means, the optical filter comprising a plurality of bands, the transmission frequency of the bands varying along the detector means, the optical filter being aligned with the spectral axis of the spectral signal, the transmission frequencies of the bands being matched to and aligned with component frequencies of the spectral image; and the optical filter being directly deposited on the detector means such that the optical filter remains in alignment with the detector means despite temperature changes, shock or vibration. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A spectral imaging system for detecting the optical spectrum of a target, the system comprising:
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means for receiving an optical signal from the target; dispersion means for dispersing the optical signal into a spectral signal with component spectra of the optical signal provided along a spectral axis having a frequency range; a photodetector array aligned with the spectral axis of the spectral signal for receiving and detecting the spectral signal, the photodetecter array including; a charge coupled device multiplexer formed on a semiconductor substrate; a plurality of closely spaced soft metal beads formed on a surface of the multiplexer; and a doped photosite array mounted onto the substrate and electrically connected to the charge coupled device multiplexer by the soft metal beads; an optical filter for substantially eliminating stray and background optical signals from detection by the photodetector array, the optical filter comprising a plurality of bands, the transmission frequency of the bands varying along the photodetector array, the optical filter being aligned with the spectral axis of the spectral signal, the transmission frequencies of the bands being matched to, and aligned with component frequencies of the spectral image; and the optical filter being directly deposited on the photosite array such that the optical filter remains in alignment with the photodetector array despite temperature changes, shock or vibration.
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22. A spectral imaging system for detecting the optical spectrum of a target, the system comprising:
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means for receiving an optical signal from the target; dispersion means for dispersing the optical signal into a spectral signal with component spectra of the optical signal provided along a spectral axis having a frequency range; a photodetector array aligned with the spectral axis of the spectral signal for receiving and detecting the spectral signal, the photodetector array including; a doped photosite array mounted onto a semiconductor substrate and comprising a 20×
64 array of photosite pixels, each photosite element comprising arsenic doped silicon;a PMOS charge coupled device multiplexer formed on the semiconductor substrate beneath said photosite array and having a plurality of charge collector sites arranged to correspond one for one with said photosite pixels; a plurality of closely spaced indium beads formed on a surface of the multiplexer, one bead electrically connecting each corresponding pixel and photosite; and an optical filter for substantially eliminating stray and background optical signals from detection by the photodetector array, the optical filter comprising a plurality of 100 micrometer (μ
m) wide bands, each transmitting a 250 nanometer wide spectral band, the transmission frequency of the bands varying along the photodetector array from 7.5 μ
m to 14 μ
m, the optical filter being aligned with the spectral axis of the spectral signal, the transmission frequencies of the bands being matched to, and aligned with component frequencies of the spectral image; andthe optical filter being directly deposited on the photosite array such that the optical filter remains in alignment with the photodetector array despite temperature changes, shock or vibration.
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Specification