Protective headgear comprising a curved switchable shutter and comprising multiple antireflective layers

Patent metadata

Field	Value
Publication number	US-2019091069-A1
Application number	US-201716096939-A
Country	US
Kind code	A1
Filing date	May 8, 2017
Priority date	May 12, 2016
Publication date	Mar 28, 2019
Grant date	—

Abstract

Protective headgear with a curved switchable shutter and curved front and rear cover plates and including at least two antireflective layers.

First claim

What is claimed is:

1 . A protective headgear comprising:
an automatic darkening filter that comprises a curved switchable shutter that exhibits a curvature; a front cover plate that exhibits a curvature and that is positioned in front of the shutter; and, a rear cover plate that exhibits a curvature and that is positioned in rear of the shutter,
wherein the front and rear cover plates and the shutter define an optical path that electromagnetic radiation can follow to reach the eyes of a wearer of the protective headgear;
and wherein the optical path comprises at least two antireflective layers, each antireflective layer being disposed on a major front surface or major rear surface of the rear cover plate, a major front surface or major rear surface of the front cover plate, or a major front surface or major rear surface of the curved switchable shutter.

2 . The protective headgear of claim 1 wherein the optical path comprises at least one antireflective layer that is on a major front surface or a major rear surface of the rear cover plate.

3 . The protective headgear of claim 2 wherein the optical path comprises at least one antireflective layer that is on a major front surface or a major rear surface of the curved switchable shutter.

4 . The protective headgear of claim 2 wherein the optical path comprises at least one antireflective layer that is on a major front surface or a major rear surface of the front cover plate.

5 . The protective headgear of claim 1 wherein the optical path comprises a first antireflective layer on the major rear surface of the rear cover plate and a second antireflective layer on the major front surface of the rear cover plate.

6 . The protective headgear of claim 1 wherein the optical path comprises a first antireflective layer on the major rear surface of the rear cover plate and a second antireflective layer on the major rear surface of the curved switchable shutter.

7 . The protective headgear of claim 1 wherein the optical path comprises a first antireflective layer on the major rear surface of the rear cover plate, a second antireflective layer on the major front surface of the rear cover plate, and a third antireflective layer on the major rear surface of the curved switchable shutter.

8 . The protective headgear of claim 1 wherein the optical path comprises a first antireflective layer on the major rear surface of the rear cover plate, a second antireflective layer on the major front surface of the rear cover plate, and a third antireflective layer on a major front surface or a major rear surface of the front cover plate.

9 . The protective headgear of claim 1 wherein the optical path comprises a first antireflective layer on the major rear surface of the rear cover plate, a second antireflective layer on the major front surface of the rear cover plate, a third antireflective layer on the major rear surface of the front cover plate, and a fourth antireflective layer on the major front surface of the front cover plate.

10 . The protective headgear of claim 1 wherein the optical path comprises a first antireflective layer on the major rear surface of the rear cover plate, a second antireflective layer on the major front surface of the rear cover plate, a third antireflective layer on the major rear surface of the curved switchable shutter, a fourth antireflective layer on the major rear surface of the front cover plate, and a fifth antireflective layer on the major front surface of the front cover plate.

11 . The protective headgear of claim 1 wherein at least one of the antireflective layers is a single layer of material that exhibits a refractive index less than about 1.50.

12 . The protective headgear of claim 1 wherein at least one of the antireflective layers is a multi-sublayer stack comprising two or three sublayers of materials that differ from each other in refractive index by at least about 0.3.

13 . The protective headgear of claim 1 wherein at least one of the antireflective layers is a multi-sublayer stack comprising four sublayers of materials that differ from each other in refractive index by at least about 0.3.

14 . The protective headgear of claim 13 wherein an outwardmost sublayer of the four sublayers exhibits a refractive index of at most about 1.5 and exhibits an optical thickness that is from about 80% to about 120% of the combined optical thickness of the other three sublayers.

15 . The protective headgear of claim 1 wherein at least one of the antireflective layers is disposed on a carrier layer that is adhered to a major surface of the front cover layer, the rear cover layer, or the curved, switchable shutter, by an optically clear adhesive.

16 . The protective headgear of claim 1 wherein at least one of the antireflective layers is disposed on a major front surface of a flexible front cover sheet that is a frontmost structural component of the curved, switchable shutter, or is disposed on a major rear surface of a flexible rear cover sheet that provides a rearmost structural component of the curved, switchable shutter.

17 . The protective headgear of claim 1 wherein the curvature of the front cover plate is at least generally congruent with the curvature of the curved switchable shutter, and wherein the curvature of the rear cover plate is at least generally congruent with the curvature of the curved switchable shutter.

18 . The protective headgear of claim 1 wherein the optical path includes a front air gap of from about 0.5 mm to about 4 mm between a major rear surface of the front cover plate and a major front surface of the curved, switchable shutter, and further includes a rear air gap of from about 0.5 mm to about 4 mm between a major rear surface of the curved, switchable shutter and a major front surface of the rear cover plate.

19 . The protective headgear of claim 18 wherein the rear air gap of the optical path is between about 0.5 mm and about 2 mm and is at least substantially constant over a lateral extent of the rear air gap of the optical path.

20 . The protective headgear of claim 1 wherein the curved, switchable shutter comprises:
a first polarizer having a first polarization direction;
a second polarizer having a second polarization direction, which may be the same or different from the first polarization direction; and
a first liquid-crystal cell disposed between the first and second polarizers, the liquid crystal cell containing first and second optically-transparent flexible layers that are curved and that have a first liquid crystal layer located between them.

21 . The protective headgear of claim 20 wherein the curved, switchable shutter comprises a flexible front cover sheet that is an organic polymeric material and a flexible rear cover sheet that is an organic polymeric material.

Assignees

• 3M Innovative Properties Co

Inventors

• Magnusson Kristina M
• Jarefors Kenneth
• Billingsley Britton G

Classifications

• G02B5/20

  Filters (polarising elements G02B5/30) · CPC title

• G02B1/11

  Anti-reflection coatings · CPC title

• A61F9/061

  with movable shutters, e.g. filter discs; Actuating means therefor · CPC title

• A42B3/042

  Optical devices (night vision goggles G02B23/12) · CPC title

• A61F9/04 Primary

  Eye-masks {; Devices to be worn on the face, not intended for looking through; Eye-pads for sunbathing} · CPC title