Photopic detector system having a filter with an interference element, an absorptive element and an absorber or reflector
First Claim
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1. A detector system comprising:
- a detector having a detector response with a long wavelength end; and
a filter that includes;
an interference element that substantially reflects normally incident light over a band of near-infrared wavelengths and that substantially transmits normally incident light over visible wavelengths, wherein the band has a long wavelength band edge that moves to an oblique-angle shifted band edge for oblique angle incident light;
an absorptive element that absorbs light non-uniformly over visible wavelengths, the absorptive element comprising a colorant dispersed in a polymeric matrix; and
an absorber or reflector suitable to substantially block light for wavelengths between the long wavelength end of the detector response and the oblique-angle shifted band edge;
wherein a relative response of the detector system approximates a visual response of the human eye.
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Abstract
A detector system, filter therefor, and method of making same is disclosed. The filter includes an interference element having a reflection band disposed primarily in the near infrared, and having a high transmission over most of the visible region. The filter also includes an absorptive element that absorbs light non-uniformly over the visible region. The filter when combined with a semiconductor photodiode or other suitable detector yields a detector system whose spectral responsivity closely matches the visual response of the human eye.
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Citations
19 Claims
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1. A detector system comprising:
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a detector having a detector response with a long wavelength end; and a filter that includes; an interference element that substantially reflects normally incident light over a band of near-infrared wavelengths and that substantially transmits normally incident light over visible wavelengths, wherein the band has a long wavelength band edge that moves to an oblique-angle shifted band edge for oblique angle incident light; an absorptive element that absorbs light non-uniformly over visible wavelengths, the absorptive element comprising a colorant dispersed in a polymeric matrix; and an absorber or reflector suitable to substantially block light for wavelengths between the long wavelength end of the detector response and the oblique-angle shifted band edge; wherein a relative response of the detector system approximates a visual response of the human eye. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification