Optical filter

US11016229B2 · kind B2 · utility

Assignee

• 3M INNOVATIVE PROPERTIES COMPANY · US

Inventors

• John A. Wheatley · Stillwater, US
• Gilles J. Benoit · Minneapolis, US
• Todd A. Ballen · Saint Paul, US
• Kenneth L. Smith · White Bear Lake, US
• Guanglei Du · Riverside, US
• Edward J. Kivel · Stillwater, US
• Rolf W. Biernath · Wyoming, US
• Jordan D. Whitney · Oakdale, US
• Daniel J. Schmidt · Woodbury, US

Key dates

• Filing date: May 30, 2017
• Grant date: May 25, 2021
• Expiry date: Mar 30, 2038

Classification

• Technology area (CPC G): Physics
• CPC primary: G02B5/12
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

An optical filter including a polarizer and a visible light blocking filter is described. The polarizer is configured to transmit at least 60 percent of light in a first infrared wavelength range that is incident on the polarizer at normal incidence in a first polarization state, to transmit less than 30 percent of light in a second infrared wavelength that is incident on the polarizer at normal incidence in a second polarization state orthogonal to the first polarization state, and to transmit less than 30 percent of light in a third infrared wavelength range that is incident on the polarizer with a 50 degree angle of incidence in the second polarization state. The visible light blocking filter configured to transmit at least 60 percent of light in the first infrared wavelength range at normal incidence in the first polarization state.