Optical camouflage filters
Assignee3M Innovative Properties Company
InventorsJohn A. Wheatley, Guanglei Du, David T. Yust, Neeraj Sharma, Gilles J. Benoit, Ellison G. Kawakami, Anthony M. Renstrom
Life of this patent
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Abstract
An article includes an optical filter that comprises a wavelength selective reflective layer and at least one wavelength selective absorbing layer. The optical filter has visible transmittance between 400 nm-700 nm of less than about 30% and near infrared transmittance at 830 nm-900 nm greater than about 30%.
Claims20
A printed article having an average transmittance of less than 0.1% for wavelengths between 400 nm and 700 nm and average transmittance of greater than 50% for wavelengths between 830 nm and 900 nm, the printed article comprising:
- a wavelength selective reflective layer comprising an interference filter having an average transmittance of greater than 50% for wavelengths between 830 nm and 900 nm and a transmittance of greater than 70% for wavelengths between 950 nm and 1250 nm, a transmission spectrum of the reflective layer comprising at least one peak between 400 nm and 700 nm;
- and
- at least one printed wavelength selective absorbing layer having an average visible transmittance for wavelengths between 400 nm and 700 nm of less than about 30%.
A printed article having an average transmittance of less than 0.1% for wavelengths between 400 nm and 700 nm and average transmittance of greater than 50% for wavelengths between 830 nm and 900 nm, the printed article comprising:
- a wavelength selective reflective layer comprising an interference filter having an average transmittance of greater than 50% for wavelengths between 830 nm and 900 nm, a transmission spectrum of the reflective layer comprising at least one peak between 400 nm and 700 nm;
- and
- at least one printed wavelength selective absorbing layer comprising a porous layer and one or more of a wavelength selective dye and a wavelength selective pigment disposed within pores of the porous layer, a ratio of a scattering by the porous layer in visible wavelengths between 400 nm and 700 nm to a scattering by the porous layer in near infrared wavelengths between 900 nm and 980 nm is less than 0.9.
Dependencies are inferred from the claim text.