# US 12,216,298 B2 · Optical camouflage filters

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- Number: US 12,216,298 B2
- Document ID: US12216298B2
- Status: Granted
- Kind: B2
- Application number: 17/302,662
- Filed: 2021-05-10
- Published: 2021-08-26
- Granted: 2025-02-04
- Earliest claimed: 2016-01-21
- Assignees: 3M Innovative Properties Company
- Applicants: 3M Innovative Properties Company
- Inventors: John A. Wheatley; Guanglei Du; David T. Yust; Neeraj Sharma; Gilles J. Benoit; Ellison G. Kawakami; Anthony M. Renstrom
- Web page: https://patentgrep.com/patent/US12216298B2

## CPC

- G02B 5/208: {for use with infrared or ultraviolet radiation, e.g. for separating visible light from infrared and/or ultraviolet radiation}
- G02B 5/22: Absorbing filters {(G02B5/201 - G02B5/208 take precedence)}
- G02B 5/285: {comprising deposited thin solid films (G02B5/281 - G02B5/289 take precedence; multilayered film filters for fibre optic multiplexing G02B6/29361)}
- G02B 5/28: Interference filters
- G02B 5/3025: {Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state (G02B5/3008, G02B5/3016 take precedence)}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## 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%.

## Claims

### Claim 1

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%.

### Claim 2 (depends on 1)

The printed article of claim 1 having an average transmittance of less than 0.01% for the wavelengths between 400 nm and 700 nm.

### Claim 3 (depends on 1)

The printed article of claim 1 having an average transmittance of less than 0.1% for wavelengths between 380 nm and 800 nm.

### Claim 4 (depends on 1)

The printed article of claim 1 having an average transmittance of less than 0.01% for wavelengths between 380 nm and 800 nm.

### Claim 5 (depends on 1)

The printed article of claim 1 having an average transmittance of greater than 75% for the wavelengths between 830 nm and 900 nm.

### Claim 6 (depends on 1)

The printed article of claim 1, wherein the interference filter has an average transmittance of greater than 50% for wavelengths between 900 nm and 980 nm.

### Claim 7 (depends on 1)

The printed article of claim 1 having an average transmittance of greater than 70% for wavelengths between 900 nm and 980 nm.

### Claim 8 (depends on 1)

The printed article of claim 1 having an average transmittance of greater than 50% for wavelengths between 800 nm and 1200 nm.

### Claim 9 (depends on 1)

The printed article of claim 1, having an average transmittance of greater than 75% for wavelengths between 800 nm and 1200 nm.

### Claim 10 (depends on 1)

The printed article of claim 1, wherein the wavelength selective reflective layer comprises a reflective polarizer.

### Claim 11 (depends on 1)

The printed article of claim 1, wherein the interference filter comprises a multilayer optical film.

### Claim 12 (depends on 1)

The printed article of claim 1, wherein the at least one printed wavelength selective absorbing layer comprises a porous layer and one or more of a wavelength selective dye and a wavelength selective pigment disposed within pores of the porous layer.

### Claim 13 (depends on 12)

The printed article of claim 12, wherein the one or more of the wavelength selective dye and the wavelength selective pigment absorbs light in a first spectral range and re-emits light in a different second spectral range.

### Claim 14 (depends on 1)

The printed article of claim 1, wherein the at least one printed wavelength selective absorbing layer comprises first and second printed wavelength selective absorbing layers having different optical characteristics.

### Claim 15 (depends on 14)

The printed article of claim 14, wherein the first wavelength selective absorbing layer comprises one or more of a black dye and a black pigment, and the second wavelength selective absorbing layer comprises one or more of a color dye and a color pigment.

### Claim 16 (depends on 15)

The printed article of claim 15, wherein the color dye or the color pigment comprises one or more of a cyan, a magenta, and a yellow component.

### Claim 17

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.

### Claim 18 (depends on 17)

The printed article of claim 17, wherein the ratio is less than 0.8.

### Claim 19 (depends on 17)

The printed article of claim 17, wherein the ratio is less than 0.7.

### Claim 20 (depends on 17)

The printed article of claim 17, wherein the ratio is less than 0.6.