	US 12,134,725 B2
	Liquid crystal-based light valve
Christian Schoenefeld, Babenhausen (DE); Michael Junge, Pfungstadt (DE); Mark Goebel, Darmstadt (DE); Raphael Lisicki, Mainz (DE); and Kevin Kaiser, Gross-Gerau (DE)
Assigned to Merck Patent GmbH, (DE)
Appl. No. 17/619,971
Filed by Merck Patent GmbH, Darmstadt (DE)
PCT Filed Jun. 15, 2020, PCT No. PCT/EP2020/066420 § 371(c)(1), (2) Date Dec. 16, 2021, PCT Pub. No. WO2020/254219, PCT Pub. Date Dec. 24, 2020.
Claims priority of application No. 19180639 (EP), filed on Jun. 17, 2019.
Prior Publication US 2022/0306939 A1, Sep. 29, 2022
Int. Cl. C09K 19/58 (2006.01); C09K 19/04 (2006.01); C09K 19/12 (2006.01); C09K 19/30 (2006.01); C09K 19/60 (2006.01); G02F 1/137 (2006.01)

CPC C09K 19/586 (2013.01) [C09K 19/603 (2013.01); C09K 2019/0444 (2013.01); C09K 2019/0448 (2013.01); C09K 2019/122 (2013.01); C09K 2019/123 (2013.01); C09K 2019/3004 (2013.01); C09K 2019/3009 (2013.01); C09K 2019/3016 (2013.01); C09K 2019/3019 (2013.01); C09K 2019/3021 (2013.01); G02F 1/13718 (2013.01)]

14 Claims

1. A method for the preparation of a mobile or portable device having a light valve which is operable in and electrically switchable between an optically transparent state and an opaque state, comprising the steps of:

(i) providing a liquid-crystalline medium which comprises one or more mesogenic compounds, one or more chiral compounds, at least three different dichroic dyes, one or more di- or multireactive polymerisable mesogenic compounds, and no photoinitiators as a layer interposed between two opposing transparent substrates which are each provided with an electrode,

wherein the liquid-crystalline medium has a clearing point of 70° C. or more, and

wherein the one or more di- or multireactive polymerisable mesogenic compounds are contained in the medium in an amount, based on the overall contents of the medium, of 2% by weight or less; and

(ii) polymerising the one or more di- or multireactive polymerisable mesogenic compounds in the layer by photopolymerization with light in the spectral range from 340 nm to 420 nm.