Optical camouflage filters

US11269121B2 · kind B2 · utility

Assignee

• 3M INNOVATIVE PROPERTIES COMPANY · US

Inventors

• Guanglei Du · Riverside, US
• John A. Wheatley · Stillwater, US
• Yi Hang LV · Shanghai, CN
• Anthony M. Renstrom · Maplewood, US
• Neeraj Sharma · Woodbury, US
• Fuguo Xu · Shanghai, CN

Key dates

• Filing date: May 6, 2016
• Grant date: Mar 8, 2022
• Expiry date: Aug 29, 2037

Classification

• Technology area (CPC G): Physics
• CPC primary: G02F1/21
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A system may include one or both of a light emitter (46) and a light receiver (40), and an optical filter (10). The optical filter (10) includes a wavelength selective scattering layer (14). The wavelength selective scattering layer (14) may have a near-infrared scattering ratio of less than about 0.9. The filter (10) may have a visible reflective haze ratio of greater than about 0.5. A method may include disposing the wavelength selective scattering layer (14) adjacent one or both of the light emitter (46) and the light receiver (40). The optical filter (10) may include a wavelength selective reflective layer (16). The optical filter (10) may include a wavelength selective absorbing layer (34). An article may include the optical filter (10). The wavelength selective scattering layer (14) may have an average near-infrared scattering of less than 60%, an average visible scattering of greater than 10%, and a difference between the % total visible reflectance and the % diffuse visible reflectance of less than 20.