US 12,001,111 B2
Electrically controllable device having variable diffusion by liquid crystals, and method for same
Frédéric Mondiot, Antony (FR)
Assigned to SAINT-GOBAIN GLASS FRANCE, Courbevoie (FR)
Appl. No. 17/916,449
Filed by SAINT-GOBAIN GLASS FRANCE, Courbevoie (FR)
PCT Filed Mar. 26, 2021, PCT No. PCT/FR2021/050530
§ 371(c)(1), (2) Date Sep. 30, 2022,
PCT Pub. No. WO2021/198596, PCT Pub. Date Oct. 7, 2021.
Claims priority of application No. 2003244 (FR), filed on Apr. 1, 2020.
Prior Publication US 2023/0152649 A1, May 18, 2023
Int. Cl. G02F 1/137 (2006.01); G02F 1/1334 (2006.01); G02F 1/1335 (2006.01); G02F 1/1343 (2006.01)
CPC G02F 1/13756 (2021.01) [G02F 1/13345 (2021.01); G02F 1/134309 (2013.01); G02F 1/13775 (2021.01); G02F 1/133531 (2021.01); G02F 2202/04 (2013.01)] 20 Claims
OG exemplary drawing
 
1. An electrically controllable device having variable scattering by liquid crystals, comprising a stack of layers in this order:
a first electrode with a first main surface forming a connecting surface and an opposite surface;
a dielectric electroactive layer with a first main face oriented toward the connecting surface and a second main face opposite the first main face, the dielectric electroactive layer made of a material comprising:
liquid crystals,
polymers forming a polymeric network, the liquid crystals being stabilized by the polymeric network,
a second electrode with a second connecting surface oriented toward the second main face and with an opposite surface;
the dielectric electroactive layer being visible by transparency on a side of the first electrode and/or a side of the second electrode,
wherein the material exhibits, from a temperature T1, a mesophase P, wherein the material comprises a set of domains which comprise two-dimensional topological defects,
wherein, at a temperature T′ greater than or equal to T1, the stack is capable of exhibiting at least first, second and third states in a working range which comprises all or part of the visible range,
the first state being a first scattering state and being the most scattering among the first, second and third states,
the second scattering state being a second scattering state and less scattering than the first scattering state,
and the third state being transparent or scattering and less scattering than the second scattering state,
the first, second and third states being switchable and reversible,
at least two of the first, second and third states being obtained by applying an electric field between the first and second electrodes,
and wherein the material comprises at least one dichroic dye having an absorption wavelength, or an absorption band, within the working range, and wherein the first scattering state is colored with a color C0 defined by a lightness L*0, the second less scattering state exhibits a color C1 separate from C0, defined by a lightness L*1 separate from L*0.